GRB 210610B
GCN Circular 30170
Subject
GRB 210610B: Swift detection of a burst with bright optical afterglow
Date
2021-06-10T20:06:36Z (4 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
K. L. Page (U Leicester), J.D. Gropp (PSU), J. A. Kennea (PSU),
F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and M. H. Siegel (PSU)
report on behalf of the Neil Gehrels Swift Observatory Team:
At 19:51:27 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 210610B (trigger=1054681). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 243.939, +14.391 which is
RA(J2000) = 16h 15m 45s
Dec(J2000) = +14d 23' 29"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a comlex
structure with a duration of about 100 sec. The peak count rate
was ~11000 counts/sec (15-350 keV), at ~8 sec after the trigger.
The XRT began observing the field at 19:52:51.4 UT, 83.9 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 243.9180, 14.3977 which is equivalent to:
RA(J2000) = 16h 15m 40.32s
Dec(J2000) = +14d 23' 51.7"
with an uncertainty of 6.7 arcseconds (radius, 90% containment). This
location is 77 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy.
The initial flux in the 0.1 s image was 1.07e-08 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 91 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 16:15:40.41 = 243.91836
DEC(J2000) = +14:23:56.7 = 14.39909
with a 90%-confidence error radius of about 0.61 arc sec. This position is 5.2
arc sec. from the center of the XRT error circle. The estimated magnitude is
13.70 with a 1-sigma error of about 0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.044.
Burst Advocate for this burst is K. L. Page (klp5 AT leicester.ac.uk).
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)
GCN Circular 30171
Subject
GRB 210610B: BALROG localization (Fermi Trigger 645047470 / GRB 210610827)
Date
2021-06-10T20:12:28Z (4 years ago)
From
Jochen Greiner at MPE,Garching <jcg@mpe.mpg.de>
B. Biltzinger, F. Kunzweiler, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:
The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
645047470 at 19:51:05 on 10 June 2021 were automatically fitted for spectrum
and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427;
Berlato et al. 2019, ApJ 873, 60).
The best-fit position (1 sigma statistical errors) is:
RA(2000.0) = 244.2+/-0.6 deg
Decl.(2000.0) = 16.5+/-1.2 deg
We estimate an additional systematic error of 1 deg.
Further details are available at:
https://grb.mpe.mpg.de/grb/GRB210610827/
The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB210610827/healpix
The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB210610827/json
GCN Circular 30174
Subject
GRB 210610B: GIT optical detection
Date
2021-06-10T20:45:52Z (4 years ago)
From
Harsh Kumar at Indian Inst of Tech,Bombay <harshkosli13@gmail.com>
H. Kumar(IITB), J. Stanzin (IAO), V. Bhalerao(IITB), G. C. Anupama(IIA), S.
Barway(IIA) report on behalf of the GIT team:
We observed GRB 210610B detected by Swift-BAT (K. L. Page et al., GCN
#30170), with the 0.7m GROWTH-India Telescope (GIT). We obtained a
60-sec exposure
in the r' filter. We clearly detected the afterglow in our image at
R.A.= 16:15:40.44
and DEC.= +14:23:56.65 with an uncertainty of ~0.67 arcsec. The photometric
results follow as:
-------------------------------------------------------------------
JD (start) | T_mid-T0(hrs) | Filter | Magnitude (AB) |
-------------------------------------------------------------------
2459376.3429 | 0.37 | r' | 15.98 +/- 0.1 |
-------------------------------------------------------------------
The magnitudes are calibrated against PanSTARRS (Flewelling et al., 2018)
and not corrected for Galactic extinction.
The GROWTH India Telescope (GIT) is a 70-cm telescope with a 0.7-degree
field of view, set up by the Indian Institute of Astrophysics and the
Indian Institute of Technology Bombay with support from the Indo-US Science
and Technology Forum (IUSSTF) and the Science and Engineering Research
Board (SERB) of the Department of Science and Technology (DST), Government
of India (https://sites.google.com/view/growthindia/). It is located at the
Indian Astronomical Observatory (Hanle), operated by the Indian Institute
of Astrophysics (IIA).
GCN Circular 30175
Subject
GRB 210610B: CrAO/ZTSh optical observations
Date
2021-06-10T20:50:39Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
V. Rumyantsev (CrAO), A. Pozanenko (IKI), S. Belkin (IKI), N. Pankov
(HSE) report on behalf of GRB IKI FuN:
We observed the GRB 210610B (Page et al., GCN 30170) with ZTSh 2.6m
telescope of CrAO observatory starting on June., 10 (UT) 20:19:24. We
detect the bright optical afterglow (Page et al., GCN 30170). We
continue observations and will report photometry after data receiving.
GCN Circular 30176
Subject
Swift GRB 210610B: Global MASTER-Net observations report
Date
2021-06-10T21:15:40Z (4 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin,
V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva,
D.Kuvshinov, D. Cheryasov
(Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),
D. Buckley
(South African Astronomical Observatory),
O.A. Gres, N.M. Budnev, O.Ershova
(Irkutsk State University, API),
A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),
V. Yurkov, A. Gabovich, Yu. Sergienko
(Blagoveschensk Educational State University)
MASTER-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB 210610B ( K. L. Page et al., GCN 30170) errorbox 145 sec after trigger time at 2021-06-10 19:53:52 UT, with upper limit up to 18.9 mag. The observations began at zenith distance = 30 deg. The sun altitude is -21.6 deg.
MASTER-SAAO robotic telescope located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB 210610B errorbox 0 sec after notice time and 582 sec after trigger time at 2021-06-10 20:01:10 UT, with upper limit up to 19.2 mag. The observations began at zenith distance = 52 deg. The sun altitude is -54.2 deg.
MASTER-Tavrida robotic telescope located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the Swift GRB 210610B errorbox 15 sec after notice time and 598 sec after trigger time at 2021-06-10 20:01:25 UT, with upper limit up to 20.3 mag. The observations began at zenith distance = 31 deg. The sun altitude is -19.1 deg.
MASTER-IAC robotic telescope located in Spain (IAC Teide Observatory) was pointed to the Swift GRB 210610B errorbox 3486 sec after notice time and 4069 sec after trigger time at 2021-06-10 20:59:16 UT, with upper limit up to 17.6 mag. Observations started at twilight. The observations began at zenith distance = 44 deg. The sun altitude is -12.3 deg.
The galactic latitude b = 40 deg., longitude l = 29 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=1633397
We obtain a following upper limits.
Tmid-T0 | Site |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________
160 | MASTER-Kislovodsk | C | 30 | 17.5 |
215 | MASTER-Kislovodsk | C | 40 | 17.7 |
643 | MASTER-SAAO | P\ | 120 | 18.3 |
798 | MASTER-SAAO | P\ | 430 | 19.0 | Coadd
658 | MASTER-Tavrida | C | 120 | 19.1 |
838 | MASTER-Tavrida | C | 480 | 20.0 | Coadd
658 | MASTER-Tavrida | C | 120 | 19.1 |
722 | MASTER-Kislovodsk | C | 130 | 18.2 |
722 | MASTER-Kislovodsk | P| | 130 | 18.3 |
792 | MASTER-SAAO | P\ | 140 | 18.4 |
813 | MASTER-Tavrida | C | 150 | 19.2 |
813 | MASTER-Tavrida | C | 150 | 19.1 |
967 | MASTER-SAAO | P\ | 170 | 18.5 |
997 | MASTER-Tavrida | C | 180 | 19.2 |
997 | MASTER-Tavrida | C | 180 | 19.1 |
1161 | MASTER-SAAO | P\ | 180 | 18.5 |
1341 | MASTER-SAAO | P\ | 540 | 19.1 | Coadd
1197 | MASTER-Tavrida | C | 180 | 19.4 |
1359 | MASTER-Kislovodsk | C | 180 | 13.7 |
1359 | MASTER-Kislovodsk | P| | 180 | 18.5 |
1361 | MASTER-SAAO | P\ | 180 | 18.6 |
1403 | MASTER-Tavrida | C | 180 | 19.5 |
1403 | MASTER-Tavrida | C | 180 | 19.1 |
1560 | MASTER-SAAO | P\ | 180 | 18.5 |
1603 | MASTER-Tavrida | C | 180 | 19.5 |
1603 | MASTER-Tavrida | C | 180 | 19.3 |
1760 | MASTER-SAAO | P\ | 180 | 18.6 |
1940 | MASTER-SAAO | P\ | 540 | 19.2 | Coadd
1802 | MASTER-Tavrida | C | 180 | 19.4 |
1802 | MASTER-Tavrida | C | 180 | 19.1 |
1959 | MASTER-SAAO | P\ | 180 | 18.7 |
2001 | MASTER-Tavrida | C | 180 | 19.5 |
2181 | MASTER-Tavrida | C | 540 | 20.2 | Coadd
2001 | MASTER-Tavrida | C | 180 | 19.1 |
2019 | MASTER-Kislovodsk | C | 180 | 18.2 |
2019 | MASTER-Kislovodsk | P| | 180 | 18.9 |
2159 | MASTER-SAAO | P\ | 180 | 18.5 |
2201 | MASTER-Tavrida | C | 180 | 19.5 |
2201 | MASTER-Tavrida | C | 180 | 19.3 |
2358 | MASTER-SAAO | P\ | 180 | 18.6 |
2401 | MASTER-Tavrida | C | 180 | 19.6 |
2401 | MASTER-Tavrida | C | 180 | 19.4 |
2558 | MASTER-SAAO | P\ | 180 | 16.5 |
2600 | MASTER-Tavrida | C | 180 | 19.6 |
2780 | MASTER-Tavrida | C | 540 | 20.3 | Coadd
2600 | MASTER-Tavrida | C | 180 | 19.3 |
2743 | MASTER-Kislovodsk | C | 180 | 13.8 |
2743 | MASTER-Kislovodsk | P| | 180 | 18.9 |
2757 | MASTER-SAAO | P\ | 180 | 15.7 |
2800 | MASTER-Tavrida | C | 180 | 19.6 |
2800 | MASTER-Tavrida | C | 180 | 19.4 |
2957 | MASTER-SAAO | P\ | 180 | 17.3 |
2999 | MASTER-Tavrida | C | 180 | 19.7 |
2999 | MASTER-Tavrida | C | 180 | 19.4 |
3156 | MASTER-SAAO | P\ | 180 | 16.6 |
3199 | MASTER-Tavrida | C | 180 | 18.8 |
3379 | MASTER-Tavrida | C | 540 | 19.9 | Coadd
3199 | MASTER-Tavrida | C | 180 | 18.3 |
3356 | MASTER-SAAO | P\ | 180 | 17.2 |
3398 | MASTER-Tavrida | C | 180 | 19.6 |
3398 | MASTER-Tavrida | C | 180 | 18.9 |
3418 | MASTER-Kislovodsk | C | 180 | 18.3 |
3418 | MASTER-Kislovodsk | P| | 180 | 18.8 |
3555 | MASTER-SAAO | P\ | 180 | 17.0 |
3598 | MASTER-Tavrida | C | 180 | 19.6 |
3598 | MASTER-Tavrida | C | 180 | 19.2 |
3755 | MASTER-SAAO | P\ | 180 | 17.3 |
3797 | MASTER-Tavrida | C | 180 | 19.5 |
3797 | MASTER-Tavrida | C | 180 | 19.2 |
3954 | MASTER-SAAO | P\ | 180 | 15.7 |
3997 | MASTER-Tavrida | C | 180 | 19.8 |
3997 | MASTER-Tavrida | C | 180 | 19.4 |
4154 | MASTER-SAAO | P\ | 180 | 16.4 |
4099 | MASTER-IAC | C | 60 | 17.6 |
4099 | MASTER-IAC | C | 60 | 17.3 |
4239 | MASTER-IAC | I | 180 | 16.9 |
4239 | MASTER-IAC | R | 180 | 17.1 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 30177
Subject
GRB 210610B: BOOTES-2/TELMA optical observation
Date
2021-06-10T21:25:06Z (4 years ago)
From
Youdong HU at IAA-CSIC <huyoudong072@hotmail.com>
Y.-D. Hu, T.-R. Sun, E. Fernandez-Garcia, A. J. Castro-Tirado, M.D. Caballero-Garcia, M. A. Castro Tirado (IAA-CSIC), C. Perez del Pulgar, A. Castellon, I. Carrasco (Univ. de Malaga), R. Fernandez-Munoz (IHSM/UMA-CSIC) and M. Jelinek (ASU-CAS), on behalf of a larger collaboration, report:
The 60cm BOOTES-2/TELMA robotic telescope at IHSM La Mayora (UMA-CSIC) in Algarrobo Costa (Malaga, Spain) automatically responded to the Swift trigger of GRB 210610B (Page et al. GCNC 30170). Images were taken starting after the twilight as soon as it was possible. In the first co-added 7 x 10 s exposure image, we detect the reported optical afterglow with r = 17.5+-0.2 at 20:27 UT (~0.6 hr after trigger), also pinpointed by UVOT/Swift (Page et al. GCNC 30170), MASTER (Lipunov et al. GCNC 30173) and GIT (Kumar et al. GCNC 30174). Further observations are ongoing.
We thank the staff at La Mayora for its excellent support.
GCN Circular 30178
Subject
GRB 210610B: CrAO/ZTSh optical afterglow photometry
Date
2021-06-10T22:44:37Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
V. Rumyantsev (CrAO), A. Pozanenko (IKI), S. Belkin (IKI), N. Pankov
(HSE) report on behalf of GRB IKI FuN:
We report photometry of GRB 210610B afterglow (Page et al., GCN
30170; Lipunov et al. GCNs 30173, 30176; Kumar et al. GCN 30174;
Rumyantsev et al., GCN 30175; Hu et al., GCN 30177) obtained with ZTSh
2.6m telescope of CrAO observatory.
Preliminary photometry of the optical afterglow in R- filter is following
Date UT start Filter Exp. OT Err. UL(3sigma)
(s)
2021-06-10 20:19:24 R 1*10 16.11 0.02 21.5
2021-06-10 20:59:50 R 1*10 16.99 0.02 21.2
The photometry is based on the nearby USNO-A2.0 star
USNO-A2.0_id
1043-0282589 16:15:36.30 +14:23:18.2 R=16.88
We continue observations in BVRI filters and will report photometry
after data receiving.
GCN Circular 30180
Subject
GRB210610B: MeerLICHT multi-colour photometry
Date
2021-06-10T22:52:22Z (4 years ago)
From
Paul Vreeswijk at Radboud U/Nijmegen <p.vreeswijk@astro.ru.nl>
S. de Wet (UCT), P.J. Groot (Radboud/UCT/SAAO), A.J. Levan and
P.M. Vreeswijk (Radboud) report on behalf of the MeerLICHT consortium:
"Following the detection of GRB210610B by Swift and its optical
counterpart (Page et al., GCN 30170), the 0.6m MeerLICHT telescope,
located at Sutherland, South Africa began observations of the field at
2021-06-10, 21:00:54 UT (1h9m after burst) with a repeating
sequence of optical filters: q,u,q,g,q,r,q,i,q,z, at 60s integration
time each. The q-band wavelength limits are 440-720nm.
First detections are:
q_AB = 17.25 +/- 0.01 +/- 0.02 at 21:00:54 UT
u_AB = 17.48 +/- 0.05 +/- 0.05 at 21:02:18 UT
g_AB = 17.39 +/- 0.02 +/- 0.03 at 21:05:27 UT
i_AB = 17.12 +/- 0.03 +/- 0.01 at 21:11:25 UT
z_AB = 17.10 +/- 0.07 +/- 0.02 at 21:14:26 UT
r_AB = 17.37 +/- 0.02 +/- 0.02 at 21:23:29 UT
where the first uncertainty on the magnitude is the statistical
uncertainty and the second is the uncertainty on the photometric
calibration. No correction for Galactic extinction has been made.
Inspection of DECaLS/DR3 data (Dey et al., 2019, AJ 157, 168) shows an
underlying blue galaxy, centered on RA,Dec (J2000) = 243.91823,
+14.39901, with magnitude g=22.97, r=22.87 and z=22.57.
Further monitoring is continuing.
MeerLICHT is built and run by a consortium consisting of Radboud
University, University of Cape Town, the South African Astronomical
Observatory, the University of Oxford, the University of Manchester
and the University of Amsterdam."
GCN Circular 30181
Subject
GRB 210610B: iTelescope optical afterglow observations
Date
2021-06-10T23:16:52Z (4 years ago)
From
Filipp Dmitrievich Romanov at Amateur astronomer <filipp.romanov.27.04.1997@gmail.com>
I observed the field of GRB 201223A (Page et al., GCN Circ. 30170)
with remote telescope T18 (0.32-m f/8.0 reflector + CCD) of
iTelescope.Net in observatory AstroCamp at Nerpio (Spain). Two images
(with exposures 300 seconds, BINx1) were obtained with Astrodon
luminance filter on 2021-06-10 since 21:40:19 UTC (1 hour 48 minutes
52 seconds after the trigger) and since 21:47:05 UTC (1 hour 55
minutes 38 seconds after the trigger).
I clearly detected the optical afterglow with position: RA 16:15:40.38
Dec +14:23:56.5 (+/- 0.15"). The following magnitudes were measured
from comparison to r magnitudes of nearby stars from Pan-STARRS DR1
catalogue (Chambers et al., 2016): 17.33 (+/- 0.033) and 17.281 (+/-
0.029).
Magnitudes were not corrected for Galactic extinction.
Stacked image available here:
https://www.flickr.com/photos/filipp-romanov/51238249632
GCN Circular 30182
Subject
GRB 210610B: NOT optical observations and tentative redshift
Date
2021-06-10T23:35:42Z (4 years ago)
From
Daniele B Malesani at DTU Space <malesani@space.dtu.dk>
J. P. U. Fynbo (DAWN/NBI), L. Izzo (DARK/NBI), A. de Ugarte Postigo
(HETH/IAA-CSIC), D. B. Malesani (DTU Space), T. Pursimo (NOT), report on
behalf of a larger collaboration:
We observed the optical afterglow of GRB 210610B (Page et al., GCN
30170; Kumar et al., GCN 30174; Rumyantsev et al., GCN 30175; Hu et al.,
GCN 30177; de Wet et al., GCN 30180; Romanov et al., GCN 30181) with the
Nordic Optical Telescope (NOT) equipped with the ALFOSC imager.
The optical afterglow is well detected, and we measure for it the
following coordinates (J2000, against the Gaia reference system):
RA = 16:15:40.38
Dec = +14:23:56.6
Our observation was carried out with a clear filter. Calibrating the
photometry against the r-band magnitudes of nearby Pan-STARRS point
sources, we get an AB magnitude r = 17.3 +- 0.1, at a mean epoch of 1.69
hr after the GRB.
Two spectra by 600 s each were obtained using grism #4, covering the
wavelength range 3600-9400 AA. The continuum is detected at high S/N.
While there are no strong features, we can identify the Mg II doublet
and Mg I at a redshift of z = 1.13. We propose this value as the
tentative redshift of GRB 210610B.
GCN Circular 30184
Subject
GRB 210610B: correction to GCN 30181
Date
2021-06-10T23:44:58Z (4 years ago)
From
Filipp Dmitrievich Romanov at Amateur astronomer <filipp.romanov.27.04.1997@gmail.com>
Instead "the field of GRB 201223A" meant "the field of GRB 210610B":
this line was copied from my observation of the optical afterglow of
GRB 201223A (GCN Circular #29165) with the same telescope.
GCN Circular 30187
Subject
GRB 210610B: SAO RAS optical observations
Date
2021-06-11T03:16:36Z (4 years ago)
From
Moskvitin Alexander at SAO RAS <mosk@sao.ru>
A. S. Moskvitin (SAO RAS) on behalf of the GRB follow-up team report.
We observed the field of the GRB 210610B with the SAO RAS 1-m
telescope Zeiss-1000 + CCD-photometer in BVRc Johnson-Cousins filters.
The observations started on June 10, 20:21:53 UT, since half an hour
after the burst detection by the Swift/BAT (Page et al., GCN #30170).
We clearly detected the OT (Page et al., GCN #30170; Kumar et al.,
GCN #30174; Rumyantsev et al., GCNs #30175, #30178; Hu et al.,
GCN #30177; de Wet et al., GCN #30180; Romanov, GCN #30181;
Fynbo et al., GCN #30182) with the following brightness:
UT_mid T_mid-T0, h Exp., s Rc mag (+/- 0.01 mag)
20:22:03 0.510 20 16.15
20:32:40 0.687 60 16.43
20:48:12 0.946 60 16.75
21:19:20 1.448 60 17.13
21:28:10 1.612 60 17.22
21:53:21 2.032 60 17.26
22:13:03 2.360 60 17.19
22:36:03 2.743 180 17.17
23:04:20 3.215 120 17.20
23:52:38 4.020 120 17.19
The preliminary photometry is based on the USNO-A2.0 star
from GCN #30178 (Rumyantsev et al.).
Magnitudes were not corrected for MW extinction.
GCN Circular 30188
Subject
GRB 210610B: Photometry and phot-redshift from Legacy Survey, PanSTAR, and SDSS
Date
2021-06-11T03:47:08Z (4 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
S.Y. Fu, Z.P. Zhu, D. Xu, X. Liu (NAOC) report on behalf of a larger
collaboration:
We checked the archives of Legacy Survey (LS), PanSTAR, and SDSS for GRB
210610B (Page et al., GCN 30170). From the LS, the GRB optical afterglow
(e.g., Page et al., GCN 30170) is positionally located in a bright
nucleus, which lies in the south-eastern part of an extended source in
the direction of NorthWest-SouthEast.
The source has the multi-band photometric magnitudes g = 22.97, r =
22.87, z = 22.57, and a redshift z_ph = 0.96 +/- 0.44 from LS, and also
PSF magnitudes g = 24.32 +/- 0.5 , r = 23.09 +/- 0.12, i = 24.33 +/-
0.47, z = 23.61 +/- 0.69 from PanSTAR. The source is marginally detected
by SDSS, and we measure its magnitude r ~22.8. The r-band magnitudes
from three surveys are basically consistent with each other, considering
difference of photometric methods. The LS's z_ph = 0.96 +/- 0.44 is also
consistent with the spectroscopic tentative redshift z=1.13 of the GRB
optical afterglow from the NOT (Fynbo et al., GCN 30182).
We thus think the source is likely the host galaxy of the GRB.
GCN Circular 30189
Subject
GRB 210610B: Enhanced Swift-XRT position
Date
2021-06-11T04:07:34Z (4 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester)
report on behalf of the Swift-XRT team.
Using 516 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 210610B, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 243.91883, +14.39881 which is equivalent
to:
RA (J2000): 16h 15m 40.52s
Dec (J2000): +14d 23' 55.7"
with an uncertainty of 2.2 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
GCN Circular 30190
Subject
GRB 210610B: RATIR Optical and NIR Observations
Date
2021-06-11T05:42:17Z (4 years ago)
From
Rosa Leticia Becerra Godinez at Inst. de Astronoma,UNAM <rbecerra@astro.unam.mx>
Rosa L. Becerra (UNAM), Alan M. Watson (UNAM), Nat Butler (ASU), Alexander
Kutyrev (GSFC),
William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI),
J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara
(UVI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico
Ramirez-Ruiz (UCSC), Jes��s Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM),
Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and
Vicki Toy (UMD) report:
We observed the field of GRB 210610B (K.L. Page, et al., GCN 30170 and J.P.
Osborne, et al., GCN 30189)
with the
Reionization and Transients Infrared Camera (RATIR) on the 1.5m Harold
Johnson Telescope at the Observatorio Astron��mico Nacional on Sierra San
Pedro M��rtir from 2021/06 11.16 to 2021/06 11.18 UTC (7.91 to 8.38
hours after the BAT trigger), obtaining a total of 0.33 hours exposure
in the r and i bands and 0.15 hours exposure in the Z, Y, J, and H bands.
For a source within the Swift-XRT error circle, in comparison with the
SDSS DR9 and 2MASS catalogs, we obtain the following detections and upper
limits (3-sigma):
r = 18.03 +/- 0.01
i = 17.86 +/- 0.01
Z = 17.65 +/- 0.01
Y = 17.47 +/- 0.02
J = 17.55 +/- 0.03
H = 17.43 +/- 0.03
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.
Further observations are planned.
We thank the staff of the Observatorio Astron��mico Nacional in San Pedro
M��rtir.
GCN Circular 30193
Subject
GRB 210610B: GOTO confirmation of afterglow detection
Date
2021-06-11T08:16:32Z (4 years ago)
From
Travis Mong at Monash University <yik.mong@monash.edu>
Y-L Mong (1); K. Wiersema (2); R. Starling (3); K. Ackley (1);
M. Dyer (4); D. K. Galloway (1); J. Lyman (2); K. Ulaczyk (2);
D. Steeghs (2); V. Dhillon (4); P. O'Brien (3); G. Ramsay (5);
S. Poshyachinda (6); R. Kotak (7); L. Nuttall (8); D. Pollacco (2);
R. Breton (9)
((1) Monash University, (2) Warwick University, (3) University of
Leicester, (4) University of Sheffield, (5) Armagh Observatory &
Planetarium, (6) National Astronomical Research Institute of Thailand, (7)
University of Turku, (8) University of Portsmouth, (9) University of
Manchester) report on behalf of the GOTO collaboration:
We carried out observations with the Gravitational-wave Optical
Transient Observer (GOTO) on La Palma in response to GRB 210610B (Page
et al; GCN 30170). We detect an uncatalogued source consistent with
the OT reported by Swift UVOT (Page et al.; GCN 30170) and other
facilities.
We made a series of 4x90 s exposures using our wide L-band
filter(400-700 nm) beginning around ~4hrs after the trigger, with
midtime of the first observation 23:50:18.136 UT on 10 June 2021.
We detect an uncatalogued source located at (J2000):
RA 16:15:40.369Dec +14:23:57.19
confirming the OT (Page et al.; GCN 30170, Kumar et al.;
GCN 30174, Rumyantsev et al.; GCN 30175, 30178, Hu et al.;
GCN 30177, de Wet et al.; GCN 30180, Romanov; GCN 30181,
Fynbo et al.; GCN 30182, Moskvitin et al.; GCN 30187, Osborne
Et al.; GCN 30189, Becerra et al.; GCN 30190).
We find an equivalent magnitude of g = (17.86 +/- 0.05) mag based
on calibration against PanSTARRS DR1 photometry in ATLAS_REFCAT2
(Tonry et al. 2018).
Observations are continuing.
GOTO is operated at the La Palma observing facilities of the
Universityof Warwick on behalf of a consortium including the
University ofWarwick, Monash University, Armagh Observatory, the
University ofLeicester, the University of Sheffield, the National
AstronomicalResearch Institute of Thailand (NARIT), Turku University,
Portsmouth
University, Manchester University and the Instituto de Astrofisicade
Canarias (IAC) (https://goto-observatory.org)
GCN Circular 30194
Subject
GRB 210610B: Redshift confirmation from GTC
Date
2021-06-11T08:38:27Z (4 years ago)
From
Antonio de Ugarte Postigo at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), C. Thoene, J.F. Agui Fernandez, M. Blazek, D. A. Kann (all HETH/IAA-CSIC), J. P. U. Fynbo (DAWN/NBI), L. Izzo (DARK/NBI), and D. Garcia Alvarez (GTC) report:
We observed the afterglow of GRB 210610B (Page et al., GCN 30170; Kumar et al., GCN 30174; Rumyantsev et al., GCN 30175; Hu et al., GCN 30177; de Wet et al., GCN 30180; Romanov, GCN 30181; Fynbo et al GCN 30182; Moskvitin et al. GCN 30187; Becerra et al. GCN 30190; Mong et al. GCN 30193) with OSIRIS at the 10.4m GTC telescope, located at Roque de los Muchachos Observatory, in La Palma (Spain). Observation consisted of 3 x 900 s exposures with grism R1000B, covering the range between 3700 and 7800 AA. The first spectrum started at 01:36:20 UT (5.75 hr after the burst).
The spectrum shows a very strong continuum with very weak superposed lines. We detect lines corresponding to FeII, MgII and MgI at a common redshift of z = 1.1345, in agreement with the measurement from the NOT (Fynbo et al. GCN 30182). Additionally, the high SNR allows us to detect a weak intervening system through the identification of MgII at a redshift of z = 0.557. Although the redshift 1.1345 is, strictly speaking, a lower limit, the lack of any further features at higher redshift, especially considering the high SNR of the spectrum, allows us to consider this as the redshift of the GRB.
We note that the features detected at the redshift of the GRB are very weak. We can compare their strength to a sample of long GRB afterglow features using the line strength parameter, following the method of de Ugarte Postigo et al. (2012, A&A 548, A11). For this spectrum we measure LSP = -2.1 +/- 0.8, which implies that the lines are weaker than 99.8% of the sample.
GCN Circular 30195
Subject
GRB 210610B: AGILE detection
Date
2021-06-11T09:09:32Z (4 years ago)
From
Alessandro Ursi at INAF/IAPS <alessandro.ursi@gmail.com>
A. Ursi (INAF/IAPS), F. Verrecchia (SSDC, and INAF/OAR), F. Longo (Univ.
Trieste and INFN Trieste), M. Tavani (INAF/IAPS, and Univ. Roma Tor
Vergata), A. Argan, M. Cardillo, C. Casentini, Y. Evangelista, G. Piano
(INAF/IAPS), F. Lucarelli, C. Pittori, (SSDC, and INAF/OAR), A.
Bulgarelli, V. Fioretti, F. Fuschino, N. Parmiggiani (INAF/OAS-Bologna), M.
Marisaldi (INAF/OAS-Bologna, and Bergen University), M. Pilia, A. Trois
(INAF/OA-Cagliari), I. Donnarumma (ASI), A. Giuliani (INAF/IASF-Mi), report
on behalf of the AGILE Team:
The AGILE satellite detected the long GRB 210610B at T0 = 2021-06-10
19:51:32 s (UTC), reported by Swift (GCNs #30170, #30189).
The burst is clearly visible in the AGILE scientific ratemeters of the
SuperAGILE (SA; 20-60 keV), MiniCALorimeter (MCAL; 0.4-100 MeV), and
AntiCoincidence (AC; 50-200 keV) detectors. The event lasted about 30 s and
it released a total number of 2340 counts in the SA detector (above a
background rate of 65 Hz), 37190 counts in the MCAL detector (above a
background rate of 1280 Hz), and 110300 counts in the AC detector (above a
background rate of 3800 Hz). The AGILE ratemeter light curves can be found
at http://www.agilescienceapp.it/notices/GRB210610B_AGILE_RM.png .
The event also triggered a partial high time resolution MCAL data
acquisition, from T1 = 2021-06-10 19:51:22.88 s +/- 0.01 (UTC) to T2 =
2021-06-10 19:51:40.27 +/- 0.01 s (UTC), and released 11740 counts in the
detector, above a background rate of 525 Hz. The MCAL light curve can be
found at:
http://www.agilescienceapp.it/notices/073428_GRB_MCAL_550439491.834857.png
. The time-integrated spectrum between T1 and T2 can be fitted in the
energy range 0.4-5 MeV with a power law model with ph.ind. -2.9
-0.33/+0.40. The fit results in a reduced chi-squared of 0.95 (36 d.o.f.)
and a fluence of 8.06e-06 ergs/cm^2 (90% confidence level), in the same
energy range.
Additional analysis of AGILE data is in progress. Automatic MCAL GRB alert
Notices can be found at: https://gcn.gsfc.nasa.gov/agile_mcal.html.
GCN Circular 30196
Subject
Konus-Wind detection of GRB 210610B
Date
2021-06-11T10:33:02Z (4 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
D. Frederiks, S. Golenetskii, A.Lysenko, A. Ridnaia,
D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:
The long GRB 210610B (Swift detection: Page et al., GCN 30170;
AGILE detection: Ursi et al., GCN 30195)
triggered Konus-Wind (KW) at T0=71488.184 s UT (19:51:28.184).
The burst light curve shows a bright, multi-peaked emission pulse
which starts at ~T0-27 s, and has a total duration of ~100 s.
The emission is seen up to ~10 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB210610_T71488/
As observed by Konus-Wind, the burst had
a fluence of (1.3 �� 0.1)x10^-4 erg/cm^2 and
a 64-ms peak energy flux, measured from T0 + 10.175 s,
of (1.0 �� 0.1)x10^-5 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum (measured from T0 to T0+80.384 s)
is best fit in the 20 keV - 20 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.61 (-0.04,+0.04),
the high energy photon index beta = -2.77 (-0.37,+0.21),
the peak energy Ep = 257 (-14,+15) keV,
chi2 = 97/97 dof.
The spectrum near the peak count rate (measured from T0+8.192
to T0+11.775 s) is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.20 (-0.10,+0.12),
the high energy photon index beta = -3.04 (-0.64,+0.34),
the peak energy Ep = 333 (-24,+23) keV,
chi2 = 60/76 dof.
Assuming the redshift z=1.1345 (de Ugarte Postigo et al., GCN 30194)
and a standard cosmology with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315,
and Omega_Lambda = 0.685 (Planck Collaboration, 2014),
we estimate the isotropic energy release E_iso to ~4.6x10^53 erg,
the isotropic luminosity L_iso to ~7.6x10^52 erg/s,
and the rest-frame peak energy of the time-integrated spectrum Ep,z to ~550 keV.
With these values, GRB 210204A is within 68% prediction bands
for both 'Amati' and 'Yonetoku' relations for the sample of >300 long KW GRBs
with known redshifts (Tsvetkova et al., 2021, ApJ, 908, 83),
see http://www.ioffe.ru/LEA/GRBs/GRB210610_T71488/GRB210610B_rest_frame.pdf
All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.
GCN Circular 30198
Subject
GRB 210610B: University of Siena Observatory optical photometry of the afterglow
Date
2021-06-11T14:25:00Z (4 years ago)
From
Simone Leonini at Monarrenti Obs <s.leonini@iol.it>
Alessandro Marchini, Andrea Lorini (University of Siena Observatory, Siena,
Italy), Simone Leonini (Montarrenti Observatory, Sovicille (SI), Italy),
Giacomo Bonnoli (IAA-CSIC, Granada, Spain) report:
We observed the field of GRB 210610B (Swift trigger 1054681, K.L. Page et al., GCN Circ. 30170) with the 0.3 m telescope at University of Siena Observatory (Siena, Italy, K54). The GRB was extensively observed at all wavelengths, including optical photometry from many observatories (see e.g GCN Circulars 30173, 30174, 30175, 30176, 30177, 30178, 30180, 30181, 30185, 30187, 30188, 30190, 30191, 30193).
Our observations began under good weather conditions at 2021-06-10 20:37:53 UT (~0.75 h after GRB onset) with a series of 300s CCD exposures in the Rc filter, that were later added in groups of four for the photometry and further analysis.
The optical afterglow was clearly detected at a sky position in agreement with the UVOT astrometry reported in GCN Circ. 30170.
Our data cover continuously almost 6 hours of observations until the field set below the dome horizon.
The preliminary Rc-band photometry was calibrated with stars from the APASS10 catalog (Henden et al., 2019) after conversion between the two photometric systems with the simple formula from Dymock & Miles (2009) for the CMC15 catalog: Rc=r���-0.22. Measurements are not corrected for galactic extinction. Reported uncertainties are statistical only.
The first and last measurements of our series are reported hereafter:
2021-06-10 h. 20:50 UT JD 2459376.368287, R = 16.83 �� 0.04
2021-06-11 h. 02:26 UT JD 2459376.601458, R = 17.52 �� 0.16
The evolution of the brightness is, within the limits of our precision, compatible with a single decay rate with index alpha=0.25 �� 0.04
Any enquiry on these observations can be addressed either to Alessandro Marchini (marchini@unisi.it) or to Giacomo Bonnoli (bonnoli@iaa.es).
A brief description of our instrumental setup is available at the official webpage of the Astronomical Observatory of the University of Siena:
https://www.dsfta.unisi.it/en/research/labs/astronomical-observatory
GCN Circular 30199
Subject
GRB 210610B: Fermi GBM detection
Date
2021-06-11T14:50:39Z (4 years ago)
From
Christian Malacaria at NASA-MSFC/USRA <cmalacaria@usra.edu>
C. Malacaria (USRA) and B. Hristov (UAH)
report on behalf of the Fermi GBM Team:
At 19:51:05.05 UT on the 10th of June 2021, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 210610B (trigger 645047470 / 210610827),
which was also detected by Swift (Page et al. 2021, GCN 30170).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 63 degrees.
The GBM light curve shows of 3 major peaks
with a duration (T90) of about 55 s (50-300 keV).
Spectral evolution is clear throughout the burst,
therefore we report the spectrum of the brightest peak.
The time-averaged spectrum of the first peak from T0+25.6s to T0+28.7 s is
best fit by a power law function with an exponential
high-energy cutoff. The power law index is -0.28 +/- 0.03 and
the cutoff energy, parameterized as Epeak, is 414.3 +/- 11.7 keV.
The event fluence (10-1000 keV) in this time interval is
(1.73 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+30.1 s in the 10-1000 keV band
is 27.4 +/- 0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html
For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/
GCN Circular 30201
Subject
GRB 210610B: Spectroscopy and redshift confirmation with the Himalayan Chandra Telescope
Date
2021-06-11T15:33:19Z (4 years ago)
From
Harsh Kumar at Indian Inst of Tech,Bombay <harshkosli13@gmail.com>
A. Dutta (IIA), H. Kumar (IITB), D. K. Sahu (IIA), B. Kumar (ARIES), G. C.
Anupama (IIA), V. Bhalerao (IITB), S. Barway (IIA) report on behalf of a
larger Indian collaboration:
We obtained a spectrum of the GRB 210210B detected by Swift-BAT ( K. L.
Page et al., GCN #30170 ), with the HFOSC instrument mounted on the 2-m
Himalayan Chandra Telescope (HCT) at the Indian Astronomical Observatory
(IAO). We obtained a wavelength coverage of 3800 - 8000 angstrom. We took
an 1800 second exposure on 2021 June 10 22:02 (UTC).
The spectrum has a relatively featureless blue continuum with weak
absorption features due to Fe II (rest-frame wavelength 2587, 2600 A), Mg
II (2799 A), Mg I (2853 A) at a redshift of z=1.13. The redshift is
consistent with that reported by Fynbo et al. GCN #30182, Fu et al. GCN
#30188 and A. de Ugarte Postigo et al. GCN #30194. The spectrum has not
been corrected for reddening.
We thank the staff at IAO and CREST, Hosakote, for helping with the
observations. The Indian Astronomical Observatory and CREST are operated by
the Indian Institute of Astrophysics, Bengaluru, India.
GCN Circular 30204
Subject
GRB 210610B: KAIT Optical Detection
Date
2021-06-11T17:06:02Z (4 years ago)
From
Weikang Zheng at UC Berkeley <weikang@berkeley.edu>
WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on
behalf of the KAIT GRB team:
The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory, responded to the Swift GRB 210610B (Page et al.,
GCN 30170) starting at ~10.46 hours after the Swift trigger (Page et al.
GCN 30170). A total of 60x60s images were obtained in the clear (roughly R)
filter. The optical afterglow (e.g. Page et al., GCN 30170) was clearly
detected in each single image. We measured its brightness of 18.07 +/- 0.05
mag at 10.46 hours after burst, and decayed to be 18.27 +/- 0.06 mag at
12.20 hours after burst, calibrated to the Pan-STARRS1 catalog.
GCN Circular 30205
Subject
GRB 210610B: optical afterglow observations
Date
2021-06-11T17:14:07Z (4 years ago)
From
Paul Vreeswijk at Radboud U/Nijmegen <p.vreeswijk@astro.ru.nl>
P.M. Vreeswijk (Radboud) reports on behalf of E. Broens (Mol, Belgium):
���I observed the field of GRB 210610B (Page et al., GCN 30170; Kumar et
al., GCN 30174; Rumyantsev et al., GCN 30175; Hu et al., GCN 30177; de
Wet et al., GCN 30180; Romanov et al., GCN 30181, GCN 30182; Fynbo et
al, GCN 30182; Moskvitin, GCN 30187) using a 0.28-meter f7 SCT
telescope with a Moravian G2-1600 CCD camera and Astrodon
Johnson-Cousins BVRcIc filters.
Five 180 s exposures were average combined for each filter. In the B
filter the OT was only marginally detected with a SNR ~3. The
following magnitudes were measured using eight APASS DR9 stars in the
field. The APASS DR9 r��� and i��� magnitudes were transformed to Rc and
Ic using the Jester et al. (2009, AJ 130, 873) relations.
2021-06-10 23:50:30 UT Rc 17.20 +/- 0.07
2021-06-11 00:05:37 UT V 17.74 +/- 0.09
2021-06-11 00:20:20 UT Ic 16.8 +/- 0.2
2021-06-11 00:36:00 UT B 18.4 +/- 0.2
2021-06-11 00:51:50 UT Rc 17.25 +/- 0.08
2021-06-11 01:06:23 UT V 17.71 +/- 0.09"
GCN Circular 30206
Subject
GRB 210610B: Zwicky Transient Facility afterglow detection
Date
2021-06-11T18:11:12Z (4 years ago)
From
Daniel Perley at Liverpool JMU <d.a.perley@ljmu.ac.uk>
D. A. Perley (LJMU), Y. Yao (Caltech), A. Y. Q. Ho (UC Berkeley), M.
Bulla (Stockholm/OKC), I. Andreoni (Caltech), M. Coughlin (U.
Minnesota), and E. Kool (Stockholm/OKC) report:
The Zwicky Transient Facility (ZTF; ATel #11266) observed the location
of GRB 210610B (Page et al., GCN 30170) during the night of 2021-06-11
UT as part of the regular operations of the ZTF high-cadence partnership
survey. Four separate observations of the field (ZTF field ID 533) were
obtained between 2021-06-11 05:34:44 and 2021-06-11 08:38:29, two each
in g-band and r-band.
The associated optical transient (e.g., Page et al., GCN 30170; Kumar et
al., GCN 30174) was automatically identified by the ZTF image
subtraction pipeline and assigned the identifier ZTF21abfmpwn. The
source was independently flagged as a fast transient candidate by both
the ZTF fast-transient filter pipeline developed by A. Ho and Y. Yao
(Perley et al. 2021, arXiv:2103.01968) and by the ZTFReST pipeline
(Andreoni et al. 2021, arXiv:2104.06352), on the basis of its rapid
evolution over the course of the night and coincidence with a galaxy in
Pan-STARRS and Legacy Survey reference imaging.
We provide the following photometry:
MJD t_GRB(d) filter magnitude
59376.2324 0.4050 g 18.49 +/- 0.10
59376.2751 0.4477 r 18.29 +/- 0.07
59376.3206 0.4932 r 18.44 +/- 0.07
59376.3600 0.5326 g 18.81 +/- 0.07
Photometry is as provided by the ZTF alert packets and is
reference-subtracted. Magnitudes are AB and are not corrected for
Galactic extinction.
ZTF is supported by the National Science Foundation under Grant No.
AST-2034437 and a collaboration including Caltech, IPAC, the Weizmann
Institute for Science, the Oskar Klein Center at Stockholm University,
the University of Maryland, Deutsches Elektronen-Synchrotron and
Humboldt University, the TANGO Consortium of Taiwan, the University of
Wisconsin at Milwaukee, Trinity College Dublin, Lawrence Livermore
National Laboratories, and IN2P3, France. Operations are conducted by
COO, IPAC, and UW.
DisclaimerNone
GCN Circular 30207
Subject
GRB 210610B: Swift-BAT refined analysis
Date
2021-06-11T19:08:46Z (4 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
H. A. Krimm (NSF), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), S. Laha (GSFC/UMBC),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
K. L. Page (U Leicester), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 210610B (trigger #1054681)
(Page et al., GCN Circ. 30170). The BAT ground-calculated position is
RA, Dec = 243.929, 14.398 deg which is
RA(J2000) = 16h 15m 42.8s
Dec(J2000) = +14d 23' 54.5"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 24%.
The mask-weighted light curve shows several overlapping pulses that
start at ~T-12 and end at ~T+140 s. The main peak occurs at ~T+8 s.
T90 (15-350 keV) is 69.38 +- 2.53 sec (estimated error including
systematics).
The time-averaged spectrum from T-12.04 to T+142.47 sec is best fit by
a power law with an exponential cutoff. This fit gives a photon
index 0.98 +- 0.11, and Epeak of 339.3 +- 218.6 keV (chi squared 27.43
for 56 d.o.f.). For this model the total fluence in the 15-150 keV band
is 3.6 +- 0.1 x 10^-5 erg/cm2 and the 1-sec peak flux measured from
T+7.95 sec in the 15-150 keV band is 13.5 +- 0.7 ph/cm2/sec. A fit to
a simple power law gives a photon index of 1.17 +- 0.03 (chi squared 36.54
for 57 d.o.f.). All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/1054681/BA/
GCN Circular 30208
Subject
GRB 210610B: Swift-XRT refined Analysis
Date
2021-06-11T20:48:28Z (4 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
J. D. Gropp (PSU), P.A. Evans (U. Leicester), J.P. Osborne (U.
Leicester), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), E.
Ambrosi (INAF-IASFPA) , J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto)
and K.L. Page report on behalf of the Swift-XRT team:
We have analysed 5.8 ks of XRT data for GRB 210610B (Page et al. GCN
Circ. 30170), from 87 s to 81.7 ks after the BAT trigger. The data
comprise 1.3 ks in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Osborne et al. (GCN Circ. 30189).
The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=1.13 (+0.23, -0.34). At T+133 s the decay
steepens to an alpha of 1.86 (+0.06, -0.05). The light curve breaks
again at T+397 s to a decay with alpha=0.77 (+0.06, -0.05), before a
final break at T+1153 s s after which the decay index is 1.105 (+0.023,
-0.022).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.847 (+/-0.022). The
best-fitting absorption column is 4.4 (+/-2.5) x 10^20 cm^-2, at a
redshift of 1.13, in addition to the Galactic value of 3.9 x 10^20
cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index
of 1.92 (+/-0.12) and a best-fitting absorption column of 1.1 (+1.4,
-1.1) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV
flux conversion factor deduced from this spectrum is 3.4 x 10^-11 (3.9
x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Galactic foreground: 3.9 x 10^20 cm^-2
Intrinsic column: 1.1 (+1.4, -1.1) x 10^21 cm^-2 at z=1.13
Photon index: 1.92 (+/-0.12)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01054681.
This circular is an official product of the Swift-XRT team.
GCN Circular 30213
Subject
GRB 210610B: CrAO/ZTSH optical observations (correction to the GCN circ. 30212)
Date
2021-06-11T21:35:58Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
N. Pankov (IKI, HSE), A. Pozanenko (IKI), V. Rumyantsev (CrAO), S.
Belkin (IKI, HSE) report on behalf of IKI GRB FuN:
In the GCN circ. 30212 we we incorrectly reported GRB 210610A instead of
GRB 210610B. The circular should be read as follows.
We observed the GRB 210610B (Page et al., GCN 30170) with ZTSH 2.6m
telescope of CrAO observatory starting on June 11 (UT) 19:46:53. The
optical afterglow first reported by UVOT (Page et al., GCN 30170) is
clearly detected in each of a single image of 120 exposure in R filter.
Preliminary photometry of the afterglow in the first image is following
Date UT start t-T0 Filter Exp. OT err
(mid, days) (s)
2021-06-11 19:46:53 0.99683 R 1*120 19.50 0.12
The photometry is based on nearby USNO-B1.0 (R2) stars
USNO-B1.0 id
USNO_B10-1043-00282648
USNO_B10-1043-00282621
GCN Circular 30215
Subject
GRB 210610B: CrAO/ZTSH optical observations and light curve
Date
2021-06-11T23:23:01Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
N. Pankov (IKI, HSE), A. Pozanenko (IKI), V. Rumyantsev (CrAO), S.
Belkin (IKI, HSE) report on behalf of IKI GRB FuN:
We observed the GRB 210610B (Page et al., GCN 30170) with ZTSH 2.6m
telescope of CrAO observatory starting on June 10 (UT) 20:19:24
(Rumyantsev et al., GCNs 30175, 30178). The optical afterglow first
reported by UVOT (Page et al., GCN 30170) is clearly detected in each
of a single image of 10 exposure in each of BVRI filters on June 10.
Based on our observations on June 10 (B, R - filters) and June 11
(Pankov et al., GCN 30213) we report the light curve (LC) of the
afterglow which can be found in
http://grb.rssi.ru/GRB210610B/GRB210610B_LC.png
Initial phase of the LC from 0.02 days and up to 0.07 days can be
approximated by a single power law with index of -0.9, and after that we
observe plateau phase at least up to 0.18 days after trigger (see figure
above).
GCN Circular 30216
Subject
GRB 210610B: Liverpool Telescope optical photometry
Date
2021-06-11T23:27:49Z (4 years ago)
From
Daniel Perley at Liverpool JMU <d.a.perley@ljmu.ac.uk>
D. A. Perley (LJMU) reports:
The 2m robotic Liverpool Telescope observed the location of the optical
afterglow of GRB 210610B (Page et al., GCN 30170) using the IO:O camera
on 2021-06-11 UT between 22:45:44 and 22:55:45. Photometry with
reference to SDSS secondary standard stars in the field gives the
following magnitudes:
dt_GRB(d) magnitude
1.12521 u = 20.43 +/- 0.11
1.12103 g = 20.04 +/- 0.05
1.12244 r = 19.81 +/- 0.02
1.12383 i = 19.61 +/- 0.03
1.12694 z = 19.49 +/- 0.06
DisclaimerNone
GCN Circular 30217
Subject
GRB 210610B: ALMA detection
Date
2021-06-12T00:00:13Z (4 years ago)
From
Tanmoy Laskar at U of Bath <tanmoylaskar@gmail.com>
T. Laskar (University of Bath), K. D. Alexander (Northwestern), C.
Kilpatrick (Northwestern), G. Schroeder (Northwestern), W. Fong
(Northwestern), E. Berger (Harvard), R. Margutti (Northwestern), C. G.
Mundell (University of Bath), and P. Schady (University of Bath) report on
behalf of a larger collaboration:
"We observed GRB 210610B (Page et al. GCN 30170) with the Atacama Large
Millimeter/Submillimeter Array (ALMA) beginning on 2021 June 11 at 06:21:02
UT (10.5 hr after the burst) at 90.5 GHz. Preliminary analysis reveals a mm
source with flux density of ~ 0.9 mJy at position:
RA (J2000) = 16:15:40.410 (+/- 0.005)
Dec (J2000) = +014:23:56.70 (+/- 0.01)
consistent with the X-ray position (Osborne et al. GCN 30189) and optical
position (Page et al., GCN 30170; Kumar et al. GCN 30174). Follow-up
observations are planned.
We thank the JAO staff, AoD, P2G, and the entire ALMA team for their help
with these observations."
GCN Circular 30218
Subject
GRB 210610B: VLA detection
Date
2021-06-12T00:02:52Z (4 years ago)
From
Kate Alexander at Northwestern U <kate.alexander@northwestern.edu>
K. D. Alexander (Northwestern), T. Laskar (University of Bath), C.
Kilpatrick (Northwestern), G. Schroeder (Northwestern), W. Fong
(Northwestern), E. Berger (Harvard), R. Margutti (Northwestern), C. G.
Mundell (University of Bath), and P. Schady (University of Bath) report on
behalf of a larger collaboration:
We observed GRB 210610B (Page et al. GCN 30170) at a mean frequency of 14.7
GHz with the Karl G. Jansky Very Large Array (VLA; Program 21A-241)
beginning 2021 June 11.22 UT (9.4 hours after the burst). We detect a radio
source with a preliminary flux density of ~0.25 mJy at:
RA (J2000) = 16:15:40.381
Dec (J2000) = +14:23:56.59
with an uncertainty of 0.07 arcsec in each coordinate. This position is
fully consistent with the optical afterglow (Page et al. GCN 30170; Kumar
et al. GCN 30174) and the refined Swift/XRT afterglow position (Osborne et
al. GCN 30189). Additional follow-up observations are planned.
We thank the VLA staff for rapidly approving and executing these
observations.
GCN Circular 30220
Subject
GRB 210610B: MITSuME Akeno optical observation
Date
2021-06-12T06:19:18Z (4 years ago)
From
Ryohei Hosokawa at Tokyo Institute of Technology <hosokawa@hp.phys.titech.ac.jp>
R. Noto, R. Hosokawa, K. L. Murata, M. Niwano, N. Ito, H. Takamatsu,
Y. Imai, S. Sato, M. Takaku, R. Yamaguchi, Y. Yatsu, and N. Kawai
(TokyoTech) report on behalf of the MITSuME collaboration:
We observed the field of GRB 210610B (Page et al. GCN #30170, Ursi et
al. GCN #30195, Frederiks et al. GCN #30196, Malacaria et al. GCN
#30199) with the optical three color (g', Rc, and Ic) CCD cameras
attached to the MITSuME 50 cm telescope Akeno. The observation with a
series of 60 sec exposures started at 2021-06-11 10:33:20 UT (14.7
hours after Swift BAT trigger). We stacked the images with good
conditions. We detected the afterglow reported previously (Page et al.
GCN #30170, Kumar et al. GCN #30174, Rumyantsev et al. GCN #30175,
Lipunov et al. GCN #30176, Hu et al. GCN #30177, Rumyantsev et al. GCN
#30178, Wet et al. GCN #30180, Romanov et al. GCN #30181, Fynbo et al.
GCN #30182, Moskvitin et al. GCN #30187, Becerra et al. GCN #30190,
Mong et al. GCN #30193, Postigo et al. GCN #30194, Marchini et al. GCN
#30198, Dutta et al. GCN #30201, Zheng et al. GCN #30204, Vreeswijk et
al. GCN #30205, Perley et al. GCN #30206, Pankov et al. GCN #30212,
Pankov et al. GCN #30215, Perley et al. GCN #30216, Laskar et al. GCN
#30217, Alexander et al. GCN #30218)
We measured the magnitudes as follows.
MID-UT T-EXP[sec] measured magnitudes
------------------------------------------------------------------------------------------------
2021-06-11 12:51:05 9780 g'=19.3+/-0.2, Rc=18.9+/-0.1, Ic=18.8+/-0.1
------------------------------------------------------------------------------------------------
T-EXP: Total Exposure time
We used PS1 catalog for flux calibration.
The magnitudes are expressed in the AB system.
The images were processed in real-time through the MITSuME GPU
reduction pipeline (Niwano et al. 2021, PASJ, Vol.73, Issue 1, Pages
4-24; https://github.com/MNiwano/Eclaire).
GCN Circular 30221
Subject
GRB210610B: SARA-KP 0.9m Optical Afterglow Detection
Date
2021-06-12T06:40:48Z (4 years ago)
From
Samalka Anandagoda at Clemson University <iananda@g.clemson.edu>
S. Anandagoda, K. Pellegrin, and D. Hartmann report:
We observed the field of GRB 210610B detected by Swift BAT (K. L. Page et al., GCN #30170), BALROG (B. Biltzinger et al., GCN #30171), GIT (H. Kumar et al., GCN #30174), V. Rumyantsev et al., V. Lipunov et al., Hu et al., Romanov, Fynbo et al.,Moskvitin et al. and Becerra et al. using the SARA 0.9m optical telescope located at Kitt Peak, AZ, USA, equipped with the Alta-E6-1105 camera.
Observation started at 04:40:42 UTC on 2021-06-12 and ended at 05:43:44 UTC on 2021-06-12. We obtained a series of 150s exposure frames in the Bessell R filter. We detect the optical afterglow of GRB 210610B at the enhanced Swift-XRT position (Osborne et al. GCN 30189).
The estimated magnitude of the GRB afterglow was 20.35 found by stacking 20 images of 150s each in the Bessell R band filter.
T_start-T0 (hrs) T_end-T0 (hrs) Start Date (UTC) Filter Magnitude (mag)
----------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------------
32:34 33:37 2021-06-12T04:40:42 R 20.35
Photometry is done based on the PanSTARRS catalog.
The Southeastern Association for Research in Astronomy (SARA) consortium operates three telescopes: the 0.9-m SARA-KP at Kitt Peak in Arizona, and the 0.6-m SARA-CT at Cerro Tololo in Chile, and the 1.0-m SARA-RM (formerly the JKT) telescope at Roque de los Muchachos Observatory in the Canary Islands. For more information see: Keel et al. (2016): https://iopscience.iop.org/article/10.1088/1538-3873/129/971/015002 <https://iopscience.iop.org/article/10.1088/1538-3873/129/971/015002>
---------------------------------------------------------------------------------------
GCN Circular 30226
Subject
GRB 210610B: optical photometry of afterglow at INASAN/Simeiz
Date
2021-06-12T19:16:14Z (4 years ago)
From
Mansur Ibrahimov at INASAN <mansur@inasan.ru>
M. Ibrahimov, M. Nalivkin, I. Nikolenko (all from INASAN,
Moscow, Russia) and O. Pons (IGA, Havana, Cuba) report on
behalf of a larger team:
Using Zeiss 1m telescope and 4K FLI PL16803 CCD of Simeiz
Obserbatory (Collective Using Center of INASAN), we
observed the field of GRB 210610B (Page et al., GCN
30170). 15x120sec images were acquired through Bessel R
filter on 2021-06-11/00:03:07 UT (midpoint time, 4.18
hours after the trigger) with a total exposure time of
1800 sec.
Optical afterglow (for a list of the most full references
see e.g. Hosokawa et al., GCN 30220 and Anandagoda et al.,
GCN 30221) was clearly seen in all 15 individual R images.
Photometry of the optical afterglow using stacked R-image
calibrated against USNO-B1 R1-mag of 2 nearby stars,
resulted in: R = 17.61 +/- 0.02 mag.
Research was supported by Project No. RFMEFI61319X0093
(Russian Ministry of Science and High Education, Agreement
No. 075-15-2019-1716 by 2019 Nov 20) and Project No.
19-29-11013 (Russian Foundation of Fundamental
Investigation, Agreement No. 19-29-11013\20 by 2021 Jan
21).
GCN Circular 30227
Subject
GRB 210610B: Continued KAIT Optical Detection
Date
2021-06-12T20:26:48Z (4 years ago)
From
Weikang Zheng at UC Berkeley <weikang@berkeley.edu>
WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on
behalf of the KAIT GRB team:
We continued observing the optical afterglow of GRB 210610B
(e.g. Page et al., GCN 30170; Zheng & Filippenko, GCN 30204) with
the 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory. A total of 30x60s images were obtained in the
clear (roughly R) filter. The optical afterglow was detected in the
coadd image with a mag of 20.0 +/- 0.2 at ~1.44 days after burst,
calibrated to the Pan-STARRS1 catalog.
GCN Circular 30228
Subject
GRB 210610B: optical observations from Burke-Gaffney Observatory and Abbey Ridge Observatory
Date
2021-06-13T00:40:00Z (4 years ago)
From
Filipp Dmitrievich Romanov at Amateur astronomer <filipp.romanov.27.04.1997@gmail.com>
Filipp D. Romanov (Russia) and David J. Lane (Saint Mary's University,
Canada) report:
Filipp Romanov observed optical afterglow of GRB 210610B (Page et al.,
GCN Circ. 30170) remotely using telescopes: 0.61-m f/6.5 Corrected
Dall-Kirkham of Burke-Gaffney Observatory (BGO, Dave Lane is
Observatory Director) and 0.355-m f/6.2 Schmidt-Cassegrain of Abbey
Ridge Observatory (ARO, it is owned by D. Lane) on 2021-06-11.
Two images (with exposures 240 and 300 seconds) were obtained on BGO
with Sloan i' filter; on ARO were obtained two clear (unfiltered)
images (with exposures 840 and 900 seconds) and two images (with
exposures 900 and 840 seconds) with Cousins R filter.
F. Romanov measured following magnitudes of afterglow from comparison
to i' magnitudes of nearby stars from the SDSS Photometric Catalogue
DR12 (Alam et al., 2015) for BGO images and from r' magnitudes for ARO
unfiltered images; from comparison to R magnitudes of nearby stars
from USNO-A2.0 catalogue (Monet et al., 1998) for ARO Rc images:
UTC midtime
of exposure T_mid-T0, h Magnitude Mag. error
-------------------------------------------------------
02:07:55 6.27 17.45 i' 0.12
02:09:15 6.30 17.64 r' 0.03
02:14:20 6.38 17.61 i' 0.08
02:27:12 6.60 17.36 Rc 0.05
02:44:54 6.89 17.78 r' 0.08
03:03:24 7.20 17.50 Rc 0.08
-------------------------------------------------------
Magnitudes were not corrected for Galactic extinction.
Images available here:
http://www.ap.smu.ca/~bgo/sm/id.php?app=0&id=15162
http://aro.abbeyridgeobservatory.ca/sm/id.php?app=0&id=3325
http://www.ap.smu.ca/~bgo/sm/id.php?app=0&id=15163
http://aro.abbeyridgeobservatory.ca/sm/id.php?app=0&id=3326
http://aro.abbeyridgeobservatory.ca/sm/id.php?app=0&id=3327
http://aro.abbeyridgeobservatory.ca/sm/id.php?app=0&id=3328
GCN Circular 30230
Subject
GRB 210610B: Further SAO RAS optical observations
Date
2021-06-13T14:58:18Z (4 years ago)
From
Moskvitin Alexander at SAO RAS <mosk@sao.ru>
A. S. Moskvitin and O. A. Maslennikova (SAO RAS),
report on behalf of the GRB follow-up team.
We observed the field of the GRB 210610B (Page et al., GCN #30170)
with the SAO RAS 1-m telescope Zeiss-1000 + CCD-photometer in BVRc
Johnson-Cousins filters on June 11 and 12.
The GRB OT is clearly detected in the stacked frames
with the following brightness.
Date UT_start UT_end Exp., s T_mid-T0, d R mag
June 11 18:54:36--20:03:45 4 x 300 0.98453 19.33 +/- 0.01
June 11 23:14:36--23:49:13 5 x 300 1.15309 19.62 +/- 0.02
June 12 21:28:37--22:47:50 6 x 300 2.09498 20.67 +/- 0.06
The preliminary photometry is based on the USNO-A2.0 star
from GCN #30178 (Rumyantsev et al.) and previous GCN #30187.
Magnitudes were not corrected for MW extinction.
GCN Circular 30231
Subject
GRB 210610B: iTelescope optical afterglow observations
Date
2021-06-13T18:36:43Z (4 years ago)
From
Arto Oksanen at Nyrola Obs., Finland <oksanen@nyrola.jklsirius.fi>
Markku Nissinen (Taurus Hill Observatory, Varkaus, Finland) and Arto Oksanen
(Hankasalmi Observatory, Hankasalmi, Finland) report:
We have detected GRB 210610B optical afterglow (Page et al., GCN30170) using
iTelescope T18 (0.32-m f/8.0 + CCD in AstroCamp at Nerpio, Spain), iTelescope T21
(0.43-m f/6.8 + f/4.5 focal reducer + CCD in New Mexico Skies at Mayhill,
New Mexico, USA) and iTelescope T11 (0.50-m f/6.8 + f/4.5 focal reducer + CCD
in New Mexico Skies at Mayhill, New Mexico, USA).
We took total of 24 exposures with clear (CR), V and R filters.
The afterglow was clearly detected with each filter at the position
RA 16:15:40.43 DEC +14:23:57.4.
The following magnitudes were measured from comparison of a nearby star
(V = 13.97, r'=13.70) from the APASS DR9 catalogue (Henden+, 2016):
------------------------------------------------------------------------------
JD UTC Mag Err Filter AirMass Telescope Exposure(s)
------------------------------------------------------------------------------
2459376.36806 June 10 20:50 16.79 0.05 CR 1.28 T18 7x60
2459376.37868 June 10 21:05 17.15 0.10 V 1.24 T18 10x60
2459376.64285 June 11 03:25 17.76 0.02 CR 1.29 T21 2x300
2459376.65108 June 11 03:37 17.95 0.12 R 1.26 T11 5x300
------------------------------------------------------------------------------
We used r' reference magnitude for the clear filter and the R filter measurements.
GCN Circular 30238
Subject
GRB 210610B: REM optical/NIR observations of the afterglow
Date
2021-06-15T18:34:17Z (4 years ago)
From
Paolo D'Avanzo at INAF-OAB <pda.davanzo@gmail.com>
P. D'Avanzo, A. Melandri, S. Covino, D. Fugazza, (INAF-OAB) on behalf of the REM team, report:
We observed the field of GRB 210610B (Page et al., GCN Circ. 30170) with the REM 60cm robotic telescope located at the ESO premise of La Silla (Chile).
The observations were performed starting on 2021 June 10 at 23:14:12 UT (i.e. 3.38 hours after the burst) and were carried in the g, r, i, z, J, H and K bands.
The optical/NIR afterglow (Page et al., GCN Circ. 30170) is detected with the following magnitudes:
g = 17.48 +/- 0.10
r = 17.02 +/- 0.06
i = 17.30 +/- 0.10
z = 16.13 +/- 0.15 (*)
(AB; calibrated against the Pan-STARRS catalogue)
(*): image affected by fringes
J = 15.94 +/- 0.23
(Vega; calibrated against the 2MASS catalogue)
at a mid time of t-t0 = 4.01 hours.
GCN Circular 30243
Subject
GRB 210610B: AbAO optical observations
Date
2021-06-16T21:40:26Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
N. Pankov (HSE, IKI), A. Pozanenko (IKI), R. Ya. Inasaridze (AbAO), S.
Belkin (IKI), V. R. Ayvazian (AbAO), G. V. Kapanadze (AbAO) report on
behalf of IKI GRB FuN:
We observed the GRB 210610B (Page et al., GCN 30170) with AS-32
telescope of Abastumani observatory (AbAO) in R-filter on June, 13. The
optical afterglow first reported by UVOT (Page et al., GCN 30170) is
clearly detected is detected in stacked image. Preliminary photometry of
the afterglow is following
Date UT start t-T0 Filter Exp. OT Err. UL(3sigma)
(mid, days) (s)
2021-06-13 17:06:46 2.88564 R 72*60 21.25 0.14 22.6
The photometry is based on calibrations stars reported in (Pankov et
al., GCN 30213).
GCN Circular 30245
Subject
GRB 210610B: CrAO/ZTSH continued optical observations and light curve
Date
2021-06-16T22:55:29Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
N. Pankov (IKI, HSE), A. Pozanenko (IKI), V. Rumyantsev (CrAO), S.
Belkin (IKI, HSE) report on behalf of IKI GRB FuN:
We observed the GRB 210610B (Page et al., GCN 30170) with ZTSH 2.6m
telescope of CrAO observatory on June 10,11 (Rumyantsev et al., GCNs
30175, 30178; Pankov et al., GCN 30213) and June 12 - 14. The optical
afterglow first reported by UVOT (Page et al., GCN 30170) is clearly
detected in each epochs. Some preliminary photometry is following.
Date UT start t-T0 Filter Exp. OT err UL(3 sigma)
(mid, days) (s)
2021-06-12 20:54:55 2.0545 R 2*120 20.80 0.10 22.2
2021-06-12 22:41:00 2.1282 R 2*120 20.89 0.10 22.8
2021-06-14 20:40:19 4.0649 R 25*120 21.90 0.11 23.3
The photometry is based on calibrations stars reported in (Pankov et
al., GCN 30213).
Based on our observations in ZTSh on June 10-14, AbAO (Pankov et al.,
GCN 30243) and photometry reported in GCNs we report the light curve of
the afterglow which can be found in
http://grb.rssi.ru/GRB210610B/GRB210610B_LC.png
After plateau phase lasting up to ~ 0.3 days in R-filter, the LC can be
approximated by a single power law with index of -1.6.
GCN Circular 30247
Subject
GRB 210610B: Swift/UVOT Detection
Date
2021-06-17T13:37:18Z (4 years ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
M. H. Siegel (PSU), M. Baer (PSU) and K. L. Page (U. Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 210610B
92 s after the BAT trigger (Page et al., GCN Circ. 30170). A fading source consistent
with the XRT position (Osborne et al. GCN Circ. 30189) and the previously reported
optical counterpart (Kumar et al., GCN Circ. 30174; Rumyantsev et al. GCN Circ.
30175; Hu et al., GCN Circ. 30177; de Wet et al., GCN Circ. 30180; Romanov, GCN Circ.
30181; Fynbo et al., GCN Circ. 30182; Moskvitin, GCN Circ. 30187; Fu et al., GCN Circ.
30188) is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 16:15:40.40 = 243.91833 (deg.)
Dec (J2000) = +14:23:56.9 = 14.39915 (deg.)
with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence).
Preliminary detections using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white (fc) 92 242 147 13.63+/-1.10
white 584 1355 225 15.24+/-0.02
white 172034 172423 377 20.22+/-0.14
white 286441 292869 328 20.71+/-0.23
white 452008 515231 4066 21.69+/-0.16
v 634 1405 97 15.63+/-0.05
v 6631 51903 659 18.26+/-0.09
b 560 1331 77 15.78+/-0.04
b 81150 133027 865 20.08+/-0.14
u (fc) 304 554 245 13.86+/-0.03
u 707 1306 58 14.93+/-0.04
u 4850 5040 186 16.68+/-0.05
u 45786 46567 761 18.06+/-0.05
u 131743 132650 885 20.00+/-0.18
u 365977 418267 3970 21.42+/-0.29
uvw1 683 1282 58 14.51+/-0.06
uvw1 4645 4845 196 16.26+/-0.07
uvw1 7041 45779 989 17.54+/-0.06
uvw1 125974 137480 881 19.53+/-0.20
uvw1 200561 247267 1111 19.95+/-0.24
uvm2 6836 7036 196 16.61+/-0.10
uvw2 783 1034 38 15.05+/-0.09
uvw2 50521 51421 885 18.44+/-0.10
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.044 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 30316
Subject
GRB 210610B: T-CAT optical observations
Date
2021-06-25T14:40:15Z (4 years ago)
From
Denis Marchais at Amateur astronomer <denis.marchais@free.fr>
I observed the field of GRB 210610B (Page et al., GCN #30170) with the
T-CAT telescope 0.4-meter f/4 Newton with a f/3 reducer, IR-cut filter
at 630nm and ZWO ASI533MC camera, located in Cintegabelle, France, on
June 11, 12 and 13.
The camera has a Sony sensor with Bayer filters R,G,B, that fairly
match the standard Bc, Vc, and r' filters considering the additional
IR-cut filter. Each observation results from stacking 120x 32s exposures.
The GRB OT is clearly detected in the stacked frames at the following
location, matching other observations (e.g. , Fynho et al. GCN #30182,
Osborne et al. GCN #30186) though approaching the detection limit on
third observation, June 13th.
RA(J2000) = 16h 15m 40.39s
Dec(J2000) = +14d 23' 56.3"
The following magnitudes were obtained thanks to PixInsight photometric
calibration using nearby APASS DR10 stars.
Date UT start Filter Exp. (s) OT err
2021-06-11 23:52:21 Bc 120x 32 20.53 +/- 0.05
2021-06-11 23:52:21 Vc 120x 32 20.00 +/- 0.04
2021-06-11 23:52:21 r' 120x 32 19.64 +/- 0.04
2021-06-12 22:48:22 Bc 120x 32 21.79 +/- 0.11
2021-06-12 22:48:22 Vc 120x 32 20.91 +/- 0.07
2021-06-12 22:48:22 r' 120x 32 20.90 +/- 0.10
2021-06-13 22:45:36 Bc 120x 32 21.77 +/- 0.1
2021-06-13 22:45:36 Vc 120x 32 21.42 +/- 0.09
2021-06-13 22:45:36 r' 120x 32 21.76 +/- 0.2
I thank A. Taylor, H.-B. Eggenstein and E. Broens (GCN#30205) for sharing
information through the KNCatcher citizen-science programme initiated by
S. Antier and A. Klotz as part of GRANDMA initiative (GRANDMA Observations
of Advanced LIGO's and Advanced Virgo's Third Observational Campaign,
Antier et al. https://arxiv.org/abs/2004.04277v2).
GCN Circular 30360
Subject
GRB 210610B: JCMT SCUBA-2 sub-mm observations
Date
2021-07-03T08:56:12Z (4 years ago)
From
Ian Smith at Rice U <ian.smith.astronomy@gmail.com>
I.A. Smith (Rice U.), D.A. Perley (LJMU), and N.R. Tanvir
(U. of Leicester) report:
We observed the Swift UVOT location of GRB 210610B (Page
et al., GCN Circ. 30170) using the SCUBA-2 sub-millimeter
continuum camera on the James Clerk Maxwell Telescope.
Observations totaling 3.1 hours were obtained on UT 2021-06-11,
2021-06-12, and 2021-06-13 in good weather conditions each day.
No counterpart was detected in the individual or combined maps.
Combining all the data, the RMS background noise was 0.94 mJy/beam
at 850 microns and 5.7 mJy/beam at 450 microns; the mid-point of
the run was 1.61 days after the burst trigger.
We thank Patrice Smith, Alexis-Ann Acohido, Harriet Parsons,
Mark Rawlings, and the JCMT staff for the prompt support of these
observations that were taken under project M21AP020.
GCN Circular 30614
Subject
GRB 210610B: Assy optical observations
Date
2021-08-08T05:33:17Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
V. Kim (FAI, Pulkovo Observatory), A. Pozanenko (IKI), M. Krugov (FAI),
N. Pankov (HSE, IKI), S. Belkin (IKI) report on behalf of GRB IKI FuN:
We observed the field of GRB 210610B (Lien et al., GCN 30600) with
AZT-20 telescope of Assy-Turgen observatory starting on 2021-08-07 (UT)
20:45:22.
We clearly detect the optical afterglow (Lien et al., GCN 30600; Hu et
al., GCN 30602; Lipunov et al., GCN 30607).
Preliminary photometry of the optical afterglow in a stacked image is
following
Date UT start t-T0 Exp. Filter OT Err. UL(3sigma)
(mid, days) (s)
2021-08-07 20:45:22 0.47601 75*60 r' 21.28 0.05 23.6
The photometry is based on nearby PS1 stars.
GCN Circular 30988
Subject
GRB 210610B: Sintesz-Newton/CrAO optical observations
Date
2021-10-25T12:07:05Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
N. Pankov (HSE), S. Nazarov (CrAO), A. Pozanenko (IKI), S. Belkin (IKI,
HSE) report on behalf of IKI GRB FuN:
We observed the GRB 210610B (Page et al., GCN 30170) with
Sintesz-Newton 350mm f/5 telescope of CrAO observatory. Observation
started on 2021-06-10 (UT) 22:07:10, and continued on 2021-06-11 (UT)
20:22:38, 2021-06-12 (UT) 20:39:03, and 2021-06-13 (UT) 19:38:28. The
series consists of images with an exposure of 300 s in a Clear filter.
The optical afterglow first reported by UVOT team (Page et al., GCN
30170) is clearly detected in each epoch.
Preliminary photometry of the stacked images is following
Date UT start t-T0 Filter Exp. OT err UL(3)
(mid, days) (s)
2021-06-10 22:07:10 0.10293 Clear 5*300 17.20 0.03 20.5
2021-06-10 n/d 0.12658 Clear 5*300 17.28 0.08 21.1
2021-06-10 n/d 0.14409 Clear 5*300 17.28 0.06 21.1
2021-06-10 n/d 0.16159 Clear 5*300 17.29 0.06 21.1
2021-06-11 20:22:38 1.02165 Clear 8*300 19.58 0.10 21.2
2021-06-11 20:50:32 1.04103 Clear 6*300 19.50 0.09 21.2
2021-06-11 21:33:21 1.07077 Clear 17*300 19.69 0.09 21.5
2021-06-12 20:39:03 2.03479 Clear 14*300 20.57 0.19 21.5
2021-06-13 19:38:28 3.02571 Clear 20*300 21.26 0.17 21.8
The photometry is based on nearby USNO-B1.0 (R2) stars
USNO_B10-1043-00282648
USNO_B10-1043-00282621