GRB 210610A
GCN Circular 30160
Subject
GRB 210610A: Swift detection of a burst with an optical counterpart
Date
2021-06-10T15:26:44Z (4 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
K. L. Page (U Leicester), M. A. Baer (PSU), J.D. Gropp (PSU),
N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC),
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 15:03:43 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 210610A (trigger=1054627). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 204.285, +14.480 which is
RA(J2000) = 13h 37m 08s
Dec(J2000) = +14d 28' 49"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a complex
structure with a duration of about 15 sec. The peak count rate
was ~2000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 15:05:13.3 UT, 90.0 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 204.2823, 14.4652 which
is equivalent to:
RA(J2000) = 13h 37m 07.76s
Dec(J2000) = +14d 27' 54.7"
with an uncertainty of 2.2 arcseconds (radius, 90% containment). This
location is 54 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at https://www.swift.ac.uk/sper. No
spectrum from the promptly downlinked event data is yet available to
determine the column density.
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 93 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 13:37:07.62 = 204.28174
DEC(J2000) = +14:27:55.0 = 14.46528
with a 90%-confidence error radius of about 0.61 arc sec. This position is 2.2
arc sec. from the center of the XRT error circle. The estimated magnitude is
17.12 with a 1-sigma error of about 0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.032.
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 30161
Subject
GRB 210610A: MITSuME Akeno optical observation
Date
2021-06-10T16:13:57Z (4 years ago)
From
Ryohei Hosokawa at Tokyo Institute of Technology <hosokawa@hp.phys.titech.ac.jp>
R. Hosokawa, K. L. Murata, M. Niwano, N. Ito, H. Takamatsu, Y. Imai,
S. Sato, M. Takaku, R. Noto, R. Yamaguchi, Y. Yatsu, and N. Kawai
(TokyoTech) report on behalf of the MITSuME collaboration:
We observed the field of GRB 210610A (K. L. Page et al. GCN
Circular #30160) with the optical three color (g', Rc, and Ic) CCD
cameras attached to the
MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan. The
observation with a series of 10 sec exposures started at 2021-06-10
15:04:41 UT (58 seconds after Swift BAT trigger). We stacked the
images with good conditions. We detected the point source at the
position consistent with the afterglow detected previously (K. L. Page
et al. GCN Circular #30160)
We measured the magnitudes as follows.
filter MID-UT T-EXP[sec] measured magnitudes
------------------------------------------------------------------------------------------------
g' 15:08:47 10 16.4+/-0.4
Rc 15:08:29 50 15.3+/-0.1
Ic 15:08:29 50 15.0+/-0.2
------------------------------------------------------------------------------------------------
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 30162
Subject
GRB 210610A: Xinglong-2.16m optical afterglow observations
Date
2021-06-10T16:20:29Z (4 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
D. Xu, Z.P. Zhu, S.Y. Fu, X. Liu (NAOC) report on behalf of a larger
collaboration:
We observed the field of GRB 210610A (Page et al., GCN 30160) using the
2.16-m optical telescope located at Xinglong, Hebei, China, equipped
with the BFOSC camera. Observations started at 15:28:02 UT on
2021-06-10, i.e., 24.25 min after the burst.
An uncatalogued and varying optical transient is detected at coordinates:
R.A. (J2000) = 13:37:07.60
Dec. (J2000) = +14:27:55.0
with an error radius of ~ 0.3 arsec, positionally being well consistent
with the Swift/UVOT detection (Page et al., GCN 30160). The OT is thus
the optical afterglow of the GRB, and it has r = 16.97 +/- 0.01 mag at
26.25 min post-burst, calibrated with the nearby PanSTAR field.
Spectroscopy of the afterglow is underway.
GCN Circular 30163
Subject
GRB 210610A: GIT optical detection
Date
2021-06-10T16:57:26Z (4 years ago)
From
Harsh Kumar at Indian Inst of Tech,Bombay <harshkosli13@gmail.com>
H. Kumar(IITB), V. Bhalerao(IITB), U. Stanzin (IAO), G. C. Anupama(IIA), S.
Barway(IIA) report on behalf of the GIT team:
We observed GRB 210610A detected by Swift-BAT ( K. L. Page et al., GCN
#30160, optical counterpart reported by R. Hosokawa et al., GCN #30161 and
D. Xu et al., GCN #30162), with the 0.7m GROWTH-India Telescope (GIT). We
obtained a 300-sec exposure in the r' filter. We clearly detected the
afterglow in our image at R.A.= 13:37:07.64 and DEC.= 14:27:55.10. The
photometric results follow as:
-------------------------------------------------------------------
JD (start) | T_mid-T0(hrs) | Filter | Magnitude (AB) |
-------------------------------------------------------------------
2459376.178 | 1.22 | r' | 18.79+/- 0.05 |
-------------------------------------------------------------------
The magnitudes are calibrated against PanSTARRS DR1 (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 30164
Subject
GRB 210610A: Xinglong-2.16m redshift
Date
2021-06-10T17:26:59Z (4 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
Z.P. Zhu, D. Xu, S.Y. Fu, X. Liu (NAOC) report on behalf of a larger
collaboration:
Following the photometry of the optical afterglow (Xu et al., GCN 30162)
of GRB 210610A (Page et al., GCN 30160), we carried out 2x1800 s
spectroscopy of the afterglow using the BFOSC camera. The spectrum
covers the wavelength range 4000-9000 AA. The observation mid time is
2021 June 10.667 UT, i.e., 0.955 hr after the burst.
In our spectra, continuum is detected over the whole observed range. A
prominent absorption feature is detected around 5519 AA, which we
identify as Ly alpha in absorption, and blueward of which is Ly alpha
forest. The interpretation is confirmed by the detection of metal
absorption lines such as Si II, Si IV, C IV, all at a common redshift z
= 3.54, using old calibrations. The redshift measurement may be improved
a bit when new calibrations are available.
We thank the excellent support of the Xinglong-2.16m staff, especially
Junjun Jia and Jie Zheng.
GCN Circular 30165
Subject
GRB 210610A: Enhanced Swift-XRT position
Date
2021-06-10T18:08:33Z (4 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester)
report on behalf of the Swift-XRT team.
Using 792 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 210610A, 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 = 204.28211, +14.46540 which is equivalent
to:
RA (J2000): 13h 37m 7.71s
Dec (J2000): +14d 27' 55.4"
with an uncertainty of 2.3 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 30166
Subject
Swift GRB 210610A: MASTER optical counterpart observation
Date
2021-06-10T18:47:50Z (4 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, K.Zhirkov, V.Kornilov, E.Gorbovskoy, I.Gorbunov,P.Balanutsa,V.Vladimirov,A.Kuznetsov,
D. Vlasenko, N.Tiurina, D.Zimnukhov, V.Senik, V.Topolev, A.Chasovnikov, D.Cheryasov (Lomonosov MSU,SAI,PhysicsDepartment),
D. Buckley (South African Astronomical Observatory),
O.A. Gres, N.M. Budnev (Irkutsk State University, API),
R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico FelixAguilar OAFA),
R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity)
MASTER Global robotic net (MASTER-Net:http://observ.pereplet.ru Lipunov et al.,2010,Advances in Astronomy,2010,30L)
started Swift GRB 210610A (Page et al. GCN 30160) error box observation
at 2021-06-10 16:23:35UT at MASTER-SAAO.
There is MASTER OT J133707.60+142755.0 with m_OT~20.1m (unfiltered), that was
discovered by Swift-UVOT (Page et al. 30160) and confirmed by
Hosokawa et al. GCN 30161, Xu et al. GCN 30162, Kumar et al. GCN 30163,
and with redshift z=3.54 detected by Zhu et al. GCN 30164.
Observation and reduction will be continued.
GCN Circular 30167
Subject
Swift GRB 210610A: Global MASTER-Net observations report
Date
2021-06-10T18:47:58Z (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-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB 210610A ( K. L. Page et al., GCN 30160) errorbox 4610 sec after notice time and 4632 sec after trigger time at 2021-06-10 16:20:55 UT, with upper limit up to 17.1 mag. Observations started at twilight. The observations began at zenith distance = 58 deg. The sun altitude is -8.5 deg.
The galactic latitude b = 73 deg., longitude l = 346 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=1633161
We obtain a following upper limits.
Tmid-T0 | Site |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________
4662 | MASTER-SAAO | C | 60 | 16.8 |
4742 | MASTER-SAAO | C | 60 | 16.9 |
4822 | MASTER-SAAO | C | 60 | 17.1 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 30168
Subject
GRB210610A: MeerLICHT multi-colour photometry
Date
2021-06-10T18:56:04Z (4 years ago)
From
Paul Vreeswijk at Radboud U/Nijmegen <p.vreeswijk@astro.ru.nl>
S. de Wet (UCT), P.M. Vreeswijk (Radboud), P.J. Groot
(Radboud/UCT/SAAO), A. Levan (Radboud) report on behalf of the
MeerLICHT consortium:
Following the detection of GRB210610A by Swift and its optical
counterpart (Page et al., GCN 30160), reported at a redshift of z=3.54
by Zhu et al. (GCN 30163), the 0.6m MeerLICHT telescope, located at
Sutherland, South Africa began observations of the field at
2021-06-10, 16:48:47 UT 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 = 19.60 +/- 0.08 +/- 0.02 at 16:48:47 UT
r_AB = 19.09 +/- 0.10 +/- 0.01 at 16:56:12 UT
i_AB = 18.74 +/- 0.12 +/- 0.02 at 16:59:10 UT
z_AB = 18.37 +/- 0.19 +/- 0.02 at 17:02:09 UT,
where the first uncertainty on the magnitude is the statistical
uncertainty and the second is the uncertainty on the photometric
calibration.
In g-band the afterglow is detected only once, at 17:08:11 UT, at
g_AB = 20.18 +/- 0.18 +/- 0.03, close to the limiting magnitude of the
frame.
The source is not detected in the u-band, starting at 16:50:11 UT, at
a 5-sigma limiting magnitude of u_AB > 18.76.
Further fading of the source is observed during the ongoing sequence.
MeerLICHT is built and run by a consortium consisting of Radboud
University, the University of Cape Town, the South African Astronomical
Observatory, the University of Oxford, the University of Manchester
and the University of Amsterdam.
GCN Circular 30169
Subject
GRB 210610A: MITSuME Ishigaki optical observation
Date
2021-06-10T19:54:13Z (4 years ago)
From
Takashi Horiuchi at Ishigakijima Astronomical Obs <takashi.horiuchi@nao.ac.jp>
Takashi Horiuchi, Hidekazu Hanayama (NAOJ), Katsuhiro L. Murata,
Yoichi Yatsu, Nobuyuki Kawai (Tokyo Tech) report on behalf of the
MITSuME collaboration:
We observed the field of GRB 210610A (K. L. Page et al. GCN
Circular #30160) with the optical three
color (g', Rc, and Ic) CCD cameras attached to the 105 cm
Murikabushi telescope of Ishigakijima Astronomical Observatory,
Okinawa, Japan.
The observation with a series of 60 sec exposures started on
2021-06-10 15:40:04 UT (37 min after Swift BAT trigger).
We detected the point source at the position consistent with
the afterglow reported by K. L. Page et al. GCN Circular #30160.
Here, we removed bad data (images) with wrong sky conditions
and obtained the magnitudes as follows:
T0+[min] MID-UT T-EXP[sec] measured magnitudes
------------------------------------------------------------------------------------------------
37 2021-06-10T15:57:45 900 (60s �� 15) g'=19.41+/-0.14, Rc=18.19+/-0.04, Ic=17.73+/-0.10
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
The SDSS catalog (DR16) is used for flux calibration.
GCN Circular 30185
Subject
GRB 210610A: 1.5m OSN optical observation
Date
2021-06-10T23:49:51Z (4 years ago)
From
Youdong HU at IAA-CSIC <huyoudong072@hotmail.com>
T.-R. Sun, Y.-D. Hu, A. Sota, A. J. Castro-Tirado, M. D. Caballero-Garcia, M. A. Castro Tirado and E. Fernandez-Garcia (IAA-CSIC), on behalf of a larger collaboration, report:
Following the detection of GRB 210610A by Swift (Page et al. GCNC 30160), images in BVRI bands were obtained at the 1.5m OSN telescope in Granada (Spain) starting after the twilight as soon as it was possible. In the first I-band 90 s exposure image, the optical afterglow with I = 19.85+-0.18 at 21:12 UT (~6.1 hr after trigger) is clearly seen within the enhanced XRT position (Goad et al. GCNC 30165), which also detected by UVOT/Swift (Page et al. GCNC 30160), MITSuME (Hosokawa et al. GCNC 30161 and Horiuchi et al. GCNC 30169), Xinglong (Xu et al. GCNC 30162), MASTER (Lipunov et al. GCNC 30166) and MeerLICHT (de Wet et al. GCNC 30168). Further observations are ongoing.
We thank the staff at OSN for their excellent support.
GCN Circular 30186
Subject
GRB 210610A: Swift-BAT refined analysis
Date
2021-06-11T01:02:19Z (4 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
S. D. Barthelmy (GSFC), J. R. Cummings (CPI),
H. A. Krimm (NSF), 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+963 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 210610A (trigger #1054627)
(Page et al., GCN Circ. 30160). The BAT ground-calculated position is
RA, Dec = 204.284, 14.476 deg which is
RA(J2000) = 13h 37m 08.2s
Dec(J2000) = +14d 28' 32.5"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 26%.
The mask-weighted light curve shows a structure with two overlapping pulses
that starts at ~T-6 s and ends at ~T+11 s. The two peaks occur at
~T-2 s and ~T0, respectively. T90 (15-350 keV) is 13.62 +- 3.15 sec
(estimated error including systematics).
The time-averaged spectrum from T-5.98 to T+11.35 sec is best fit by
a simple power-law model. The power law index of the time-averaged
spectrum is 1.41 +- 0.19. The fluence in the 15-150 keV band is
1.0 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from
T-0.29 sec in the 15-150 keV band is 2.5 +- 0.4 ph/cm2/sec.
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/1054627/BA/
GCN Circular 30191
Subject
GRB 210610A: RATIR Optical and NIR Detection
Date
2021-06-11T05:59:57Z (4 years ago)
From
Alan M Watson at UNAM <alan@astro.unam.mx>
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 210610A (Page et al., GCN Circ. 30160) 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 11.18 to 2021/06 11.23 UTC (13.00 to 14.06
hours after the BAT trigger), obtaining a total of 0.61 hours exposure
in the r and i bands and 0.25 hours exposure in the Z, Y, J, and H bands.
We detect the afterglow with the following magnitudes and 3-sigma upper limit:
r = 21.39 +/- 0.06
i = 21.35 +/- 0.07
Z = 20.74 +/- 0.10
Y = 21.05 +/- 0.22
J = 20.70 +/- 0.25
H > 20.12
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.
We thank the staff of the Observatorio Astron��mico Nacional in San Pedro
M��rtir.
GCN Circular 30192
Subject
GRB 210610A: Swift-XRT refined Analysis
Date
2021-06-11T06:21:16Z (4 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
D.N. Burrows (PSU), J. D. Gropp (PSU), A.P. Beardmore (U. Leicester),
P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), T. Sbarrato
(INAF-OAB), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), J.A.
Kennea (PSU) and K.L. Page report on behalf of the Swift-XRT team:
We have analysed 7.1 ks of XRT data for GRB 210610A (Page et al. GCN
Circ. 30160), from 97 s to 45.9 ks after the BAT trigger. The data are
entirely in Photon Counting (PC) mode. The enhanced XRT position for
this burst was given by Goad et al. (GCN Circ. 30165).
The late-time light curve (from T0+4.1 ks) can be modelled with a
power-law decay with a decay index of alpha=1.05 (+/-0.10).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.84 (+0.12, -0.10). The
best-fitting absorption column is 2.6 (+9.0, -2.6) x 10^21 cm^-2, at a
redshift of 3.54, in addition to the Galactic value of 2.2 x 10^20
cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed)
0.3-10 keV flux conversion factor deduced from this spectrum is 3.5 x
10^-11 (3.7 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Galactic foreground: 2.2 x 10^20 cm^-2
Intrinsic column: 2.6 (+9.0, -2.6) x 10^21 cm^-2 at z=3.54
Photon index: 1.84 (+0.12, -0.10)
If the light curve continues to decay with a power-law decay index of
1.05, the count rate at T+24 hours will be 9.7 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.4 x
10^-13 (3.6 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01054627.
This circular is an official product of the Swift-XRT team.
GCN Circular 30197
Subject
Konus-Wind detection of GRB 210610A
Date
2021-06-11T11:56:36Z (4 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
D. Frederiks, S. Golenetskii, A.Lysenko, D. Svinkin,
A. Ridnaya, A. Tsvetkova, M. Ulanov, and T. Cline, report:
The long GRB 210610A (Swift-BAT detection: Page et al., GCN 30160; Barthelmy et al., GCN 30186),
T0 (BAT) = 15:03:43/387, was detected by Konus-Wind (KW) in the waiting mode.
A Bayesian block analysis of the KW waiting mode data in the 20-400 keV band
reveals a ~8 sigma count rate increase over background in the interval
from ~T0(BAT)-2 s to ~T0(BAT)+4 s.
The KW light curve of this burst is available
at http://www.ioffe.ru/LEA/GRBs/GRB210610A/
Modeling the KW 3-channel spectrum
by a power law with exponential cutoff (CPL) model
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha = -0.17(-0.83,+1.15) and Ep = 148(-63,+87) keV.
In the 10 keV -10 MeV band, the total burst fluence is (1.3 �� 0.5)x10^-6 erg/cm^2,
and the 2.944 s peak energy flux is (2.7 �� 0.8)x10^-7 erg/cm^2.
Assuming the redshift z=3.54 (Zhu et al., GCN 30164)
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 ~3.5x10^52 erg,
the isotropic luminosity L_iso to ~3.3x10^52 erg/s,
and the rest-frame peak energy of the time-integrated spectrum Ep,z to ~670 keV.
With these values, GRB 210610A is within 90% prediction bands for
for the 'Amati' relation 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/GRB210610A/GRB210610A_rest_frame.pdf
All the quoted errors are estimated at the 68% confidence level.
All the presented results are preliminary.
GCN Circular 30200
Subject
GRB 210610A: Spectroscopy and redshift confirmation with the Himalayan Chandra Telescope
Date
2021-06-11T15:28:13Z (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 210210A detected by Swift-BAT ( K. L.
Page et al., GCN #30160), with the HFOSC instrument mounted on the 2-m
Himalayan Chandra Telescope at the Indian Astronomical Observatory. We
obtained a wavelength coverage of 3800 - 8000 angstrom. We took a 2700
second exposure on 2021 June 10 16:48 (UTC).
The spectrum is continuum-dominated with a broad absorption feature at
~5509 A which we interpret as Lyman alpha (rest-frame wavelength 1216 A) at
a redshift of z=3.5, consistent with the redshift reported by Zhu et al.
(GCN #30164. Other absorption features due to Si II (1307 A), Si IV (1397
A), CIV (1549 A) at the same redshift are also observed. 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 30203
Subject
GRB 210610A: KAIT Optical Detection
Date
2021-06-11T16:47:54Z (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 210610A (Page et al.,
GCN 30160) starting at ~14.22 hours after the Swift trigger (Page et al.
GCN 30160). A total of 30x60s images were obtained in the clear (roughly R)
filters. We detect the optical afterglow (e.g. Page et al., GCN 30160)
in the coadd image with a mag of 21.2 +/- 0.2, calibrated to the
Pan-STARRS1 catalog.
GCN Circular 30211
Subject
GRB 210610A: CAHA 2.2m observations and light-curve behavior
Date
2021-06-11T20:58:31Z (4 years ago)
From
Alexander Kann at IAA-CSIC <kann@iaa.es>
D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC,
DARK/NBI), J. F. Agui Fernandez, C. C. Thoene, M. Blazek (all
HETH/IAA-CSIC), A. Fernandez, I. Hermelo, and S. Pedraz (all CAHA)
report:
We observed the afterglow (Page et al., GCN #30160; Hosokawa et al.,
GCNs #30161, #30169; Xu et a., GCN #30162; Kumar et al., GCN #30163;
Lipunov et al., GCN #30166; de Wet et al., GCN #30168; Sun et al., GCN
#30185; Watson et al., GCN #30191; Zheng et al., GCN #30203) of GRB
210610A, discovered by Swift (Page et al., GCN #30160) and also detected
by Konus-Wind (Frederiks et al., GCN #30197) at redshift z=3.54 (Zhu et
al., GCN #30164; Dutta et al., GCN #30200). with CAFOS mounted on the
2.2m telescope at Calar Alto, Almeria, Spain. We obtained 5 x 180 s in
Sloan i' before switching to observations of GRB 210610B. After these,
we obtained 3 x 300 s each in Sloan r' and g'.
The afterglow is detected in individual frames. Stacking the images, we
measure, against nearby comparison stars from the SDSS catalog (AB mags,
not corrected for Galactic extinction):
i' = 20.18 +/- 0.04 mag at 0.23677 d;
r' = 20.87 +/- 0.05 mag at 0.36333 d;
g' = 21.92 +/- 0.08 mag at 0.37687 d.
Using our data as well as data given in the GCN Circulars cited above,
we find that after 0.03 d, the light curve can be described with a
broken power-law fit, with alpha_1 = 0.84, alpha_2 = 1.24, and t_break =
0.16 d. Earlier data is brighter than the back-extrapolation of the fit,
indicating a steeper decay must have taken place.
GCN Circular 30212
Subject
GRB 210610A: CrAO/ZTSH optical observations
Date
2021-06-11T21:17:06Z (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 210610A (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 several nearby USNO-B1.0 (R2) stars
USNO-B1.0 id
USNO_B10-1043-00282648
USNO_B10-1043-00282621
GCN Circular 30214
Subject
GRB 210610A: CrAO/ZTSH optical observations
Date
2021-06-11T22:36:11Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI, HSE), A. Pozanenko (IKI), V. Rumyantsev (CrAO), N.
Pankov (IKI, HSE) report on behalf of IKI GRB FuN:
We observed the GRB 210610A (Page et al., GCN 30160) with ZTSH 2.6m
telescope of CrAO observatory on June 10 starting on (UT) 18:29:17, and
June 11 starting on (UT) 18:53:09. The optical afterglow first
reported by UVOT (Page et al., GCN 30160) is clearly detected in each
of a single images in R filter in both epochs.
Preliminary photometry of the afterglow in the first image on June 10,
and combined image on the June 11 is following
Date UT start t-T0 Filter Exp. OT err UL(3 sigma)
(mid, days) (s)
2021-06-10 18:29:17 0.14310 R 1*60 19.47 0.12 20.7
2021-06-11 18:53:09 1.16766 R 12*120 22.19 0.17 23.0
The photometry is based on nearby SDSS DR12 stars
SDSS-DR12_id RA DEC B(Lupton transformation) R(Lupton transformation)
J133717.13+142854.9 204.32139900 +14.48192200 17.8777 17.0295
J133703.62+142832.7 204.26512000 +14.47576300 19.2842 17.7239
J133658.05+142404.4 204.24188500 +14.40123200 20.3290 18.3616
The light curve of can be found in
http://grb.rssi.ru/GRB210610A/GRB210610A_LC.png
Initial power law index of the light curve in the first epoch is about
-0.82, and it is steepening between the two epochs down to -1.03 which
is compatible with broken power-law fit reported by D.A. Kann et al.
(GCN 30211).
GCN Circular 30229
Subject
GRB 210610A: SAO RAS optical observations
Date
2021-06-13T13:22:59Z (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 210610A (Page et al., GCN #30160)
with the SAO RAS 1-m telescope Zeiss-1000 + CCD-photometer in Rc band
on June 11 and 12.
We clearly detected the GRB OT (Page et al., GCN #30160;
Hosokawa et al., GCNs #30161, #30169; Xu et al., GCN #30162;
Kumar et al., GCN #30163; Zhu et al., GCN # 30164; Lipunov et al.,
GCN #30166; de Wet et al., GCN #30168; Horiuchi et al., GCN #30169;
Sun et al., GCN #30185; Watson et al., GCN #30191; Dutta et al.,
GCN #30200; Zheng et al., GCN #30203, Kann et al., GCN #30211;
Belkin et al., GCN #30214) in the stacked frame obtained
on June 11 and marginally detected the object in the stacked frame
obtained on June 12.
Date UT_start UT_end Exp., s T_mid-T0, d R mag
June, 11 20:12:02--21:08:03 8 x 300 1.23356 22.43 +/- 0.14
June, 12 19:46:09--21:08:36 12 x 300 2.22477 23.3 +/- 0.3
The preliminary photometry is based on magnitudes of the nearby
SDSS stars (transformed with the Lupton 2005 equations).
The OT magnitudes were not corrected for MW extinction.
GCN Circular 30232
Subject
GRB 210610A: CAHA 2.2m Second Epoch
Date
2021-06-13T21:56:50Z (4 years ago)
From
Alexander Kann at IAA-CSIC <kann@iaa.es>
D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC,
DARK/NBI), J. F. Agui Fernandez, C. C. Thoene, M. Blazek (all
HETH/IAA-CSIC), A. Fernandez-Martin (CAHA), and M. Azzaro (IAA-CSIC)
report:
We re-observed the afterglow (Page et al., GCN #30160; Hosokawa et al.,
GCNs #30161, #30169; Xu et a., GCN #30162; Kumar et al., GCN #30163;
Lipunov et al., GCN #30166; de Wet et al., GCN #30168; Sun et al., GCN
#30185; Watson et al., GCN #30191; Zheng et al., GCN #30203; Kann et
al., GCN #30211; Belkin et al., GCN #30214; Moskvitin et al., GCN
#30229) of GRB 210610A, discovered by Swift (Page et al., GCN #30160)
and also detected by Konus-Wind (Frederiks et al., GCN #30197) at
redshift z = 3.54 (Zhu et al., GCN #30164; Dutta et al., GCN #30200).
with CAFOS mounted on the 2.2m telescope at Calar Alto, Almeria, Spain.
We obtained 6 x 600 s exposure in Sloan r'.
Stacking the images, the afterglow is well-detected, and we measure,
against nearby comparison stars from the SDSS catalog (AB mags, not
corrected for Galactic extinction):
r' = 22.57 +/- 0.04 mag at 1.27366 d.
This value is in good agreement with the observations of Belkin et al.,
GCN #30214; Moskvitin et al., GCN #30229, as well as the extrapolation
of the decay found by Kann et al., GCN #30211.
GCN Circular 30233
Subject
GRB 210610A: Fermi GBM observations
Date
2021-06-14T13:35:12Z (4 years ago)
From
Peter Veres at UAH <veresp@gmail.com>
P. Veres (UAH), B. Hristov (UAH) and C. Fletcher (USRA) and C. Meegan
(UAH) report on behalf of the Fermi GBM Team:
"At 15:03:42.75 UT on 10th of June 2021, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 210610A (trigger 645030227 / 210610628).
The burst was also detected by the Swift/BAT (Page et al., GCN 30160).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 67 degrees.
The GBM light curve consists of two pulses with a duration (T90) of
about 8 s (50-300 keV). The time-averaged spectrum from T0-3.1 s to
T0+4.6 s is adequately fit by a power law function with an exponential
high-energy cutoff. The power law index is -1.11 +/- 0.15 and the
cutoff energy, parameterized as Epeak, is 247 +/- 74 keV.
The event fluence (10-1000 keV) in this time interval is (1.78 +/-
0.23)E-6 erg/cm^2. The 1-sec peak photon flux measured starting from
T0+0.7 s in the 10-1000 keV band is 3.6 +/- 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 30246
Subject
GRB 210610A: Swift/UVOT Detection
Date
2021-06-17T13:36:23Z (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 210610A
94 s after the BAT trigger (Page et al., GCN Circ. 30160). A fading source consistent
with the XRT position (Goad et al. GCN Circ. 30165) and the previously reported
optical counterpart (Hosokawa et al., GCN. Circ. 30161; Xu et al., GCN. Circ. 30162;
Kumar et al., GCN Circ. 30163; Lipunov et al., GCN. 30166; de Wet et al. GCN Circ.
30168; Horiuchi et al., GCN Circ. 30169; Youdong et al., GCN Circ. 30185; Watson et
al. GCN Circ. 30191) is detected in the initial UVOT exposures. The lack of detection
in the NUV filters for this bright counterpart is consistent with the redshift of 3.5
reported by Zhu et al. (GCN Circ. 30164) and Dutta et al. (GCN Circ. 30200).
The preliminary UVOT position is:
RA (J2000) = 13:37:07.59 = 204.28161 (deg.)
Dec (J2000) = +14:27:55.0 = 14.46527 (deg.)
with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence).
Preliminary detections and 3-sigma upper limits 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) 94 244 147 17.09+/-0.03
white 587 892 68 17.92+/-0.07
v 636 829 38 16.74+/-0.14
v 4299 4498 196 >18.92
b 562 754 38 17.69+/-0.12
b 16163 17070 885 20.57+/-0.23
b 23125 45112 1552 >21.16
u 307 557 245 >20.02
uvw1 685 4908 216 >19.37
uvm2 4503 4703 196 >19.16
uvw2 4094 4294 196 >19.10
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.032 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 30359
Subject
GRB 210610A: JCMT SCUBA-2 sub-mm observations
Date
2021-07-03T08:53:23Z (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 210610A (Page
et al., GCN Circ. 30160) 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 0.91 mJy/beam
at 850 microns and 6.2 mJy/beam at 450 microns; the mid-point of
the run was 1.73 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 30775
Subject
GRB 210610A: Maidanak and AbAO optical observations
Date
2021-09-05T23:23:17Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), A. Pozanenko (IKI), O. Burhonov (UBAI), R. Ya.
Inasaridze (AbAO), N. Pankov (IKI), V. R. Ayvazian (AbAO), D.
Datashvili (AbAO), G. V. Kapanadze (AbAO), Sh. Ehgamberdiev (UBAI)
report on behalf of IKI-GRB-FuN:
We observed the field of GRB 210610A (Page et al., GCN 30160) with
AZT-22 telescope of Maidanak Observatory and AS-32 telescope of
Abastumani observatory (AbAO). The optical afterglow (Page et al., GCN
30160; Hosokawa et al., GCN 30161; Xu et a., GCN 30162; Kumar et al.,
GCN 30163; Lipunov et al., GCN 30166; de Wet et al., GCN 30168; Hosokawa
et al., GCN 30169; Sun et al., GCN 30185; Watson et al., GCN 30191;
Zheng et al., GCN 30203; Kann et al., GCN 30211; Belkin et al., GCN
30214; Moskvitin et al., GCN 30229; Kann et al., GCN 30232; Siegel et
al., GCN 30246) is clearly detected in the stacked images. Preliminary
photometry of the afterglow is following.
Date UT start t-T0 Filter Exp. OT UL(3sigma) Telescope
(mid, days) (s)
2021-06-10 17:57:56 0.14529 R 14*300 19.62 0.03 24.0 AZT-22
2021-06-10 20:24:59 0.23769 R 42*60 20.46 0.25 20.6 AS-32
2021-06-12 16:34:08 2.07494 R 7*300 23.09 0.20 23.5 AZT-22
2021-06-13 16:44:01 3.09049 R 12*300 23.77 0.21 24.4 AZT-22
2021-06-14 17:25:22 4.11920 R 12*300 24.08 0.28 24.4 AZT-22
Photometry is based on the SDSS-DR12 nearby stars (Lupton transformations).
SDSS-DR12_id RA DEC R(Lupton)
J133717.13+142854.9 204.32139900 +14.48192200 17.0295
J133703.62+142832.7 204.26512000 +14.47576300 17.7239
Using our data in the R filter, it was found that the light curve can be
described by a broken power-law with power law indices of -0.82 and
-1.39. The break time is 0.23+/-0.17 days. These values are consistent
with the result reported by Kann et al. (GCN 30211).
The light curve can be found at
http://grb.rssi.ru/GRB210610A/GRB210610A_LC.png