GRB 201024A
GCN Circular 28760
Subject
Swift GRB201024A: Global MASTER-Net OT detection
Date
2020-10-24T03:09:25Z (5 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, N.Tyurina, E. Gorbovskoy, V.Kornilov, 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. 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),
R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),
A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),
V. Yurkov, A. Gabovich, Yu. Sergienko
(Blagoveschensk Educational State University)
MASTER-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)
located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the Swift GRB201024A (trigger 1001514) 36 sec after notice
time and 66 sec after trigger time at 2020-10-24 02:51:20 UT.
On our first (10s exposure) set we found 1 optical transient within Swift error-box (ra=125.95 dec=3.35444 r=0.05) brighter than 16.5.
T-Tmid Date Time Expt. Ra Dec Mag
---------|---------------------|-------|-----------------|-----------------|-----
229 2020-09-25 21:54:16 40 (08h 23m 48.58s, +03d 21m 13.8s) 14.9
The 5-sigma upper limit has been about 17mag
The message may be cited.
GCN Circular 28761
Subject
GRB 201024A: Swift detection of a burst with an optical afterglow
Date
2020-10-24T03:10:12Z (5 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
F. E. Marshall (NASA/GSFC), M. G. Bernardini (INAF-OAB),
P. D'Avanzo (INAF-OAB), J.D. Gropp (PSU), N. J. Klingler (PSU),
N. P. M. Kuin (UCL-MSSL), S. Laha (GSFC/UMBC/CRESST),
A. Melandri (INAF-OAB), D. M. Palmer (LANL), T. Sbarrato (INAF-OAB)
and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels
Swift Observatory Team:
At 02:48:59 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 201024A (trigger=1001514). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 125.948, +3.377 which is
RA(J2000) = 08h 23m 47s
Dec(J2000) = +03d 22' 38"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a single peak
structure with a duration of about 5 sec. The peak count rate
was ~1200 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 02:50:14.0 UT, 74.9 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source with an enhanced position: RA, Dec 125.9521,
3.3537 which is equivalent to:
RA(J2000) = 08h 23m 48.50s
Dec(J2000) = +03d 21' 13.4"
with an uncertainty of 2.1 arcseconds (radius, 90% containment). This
location is 85 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.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 3.64
x 10^20 cm^-2 (Willingale et al. 2013).
The initial flux in the 2.5 s image was 6.41e-10 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 495 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 08:23:48.55 = 125.95229
DEC(J2000) = +03:21:14.5 = 3.35403
with a 90%-confidence error radius of about 0.62 arc sec. This position is 0.7
arc sec. from the center of the XRT error circle. The estimated magnitude is
17.85 with a 1-sigma error of about 0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.03.
Burst Advocate for this burst is F. E. Marshall (marshall AT milkyway.gsfc.nasa.gov).
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 28762
Subject
GRB 201024A: MASTER correction to GCN 28760
Date
2020-10-24T03:18:40Z (5 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Due to a typo, the OT datetime data in the table(GCN 28760) was wrong
Here are the correct values
T-Tmid Date Time Expt. Ra Dec Mag
---------|---------------------|-------|-----------------|-----------------|-----
66 2020-10-24 02:51:20 10 (08h 23m 48.58s, +03d 21m 13.8s) 14.9
The OT position is coincident with UVOT and XRT position. The afterglow appears to be fading rapidly.
GCN Circular 28763
Subject
GRB 201024A: BOOTES-2/TELMA early optical observation and 1.5m OSN follow-up
Date
2020-10-24T04:10:24Z (5 years ago)
From
Youdong HU at IAA-CSIC <huyoudong072@hotmail.com>
E. Fernandez-Garcia, Y.-D. Hu, A. J. Castro-Tirado, A. Sota (IAA-CSIC), C. Perez del Pulgar, A. Castellon, I. Carrasco (Univ. de Malaga), R. Fernandez-Munoz (IHSM/UMA-CSIC), M.D. Caballero-Garcia and M. Jelinek (ASU-CAS), on behalf of a larger collaboration, report:
The 0.6m BOOTES-2/TELMA robotic telescope at IHSM La Mayora (UMA-CSIC) in Algarrobo Costa (Malaga, Spain) automatically responded to the Swift trigger of GRB 201024A (Marshall et al. GCNC 28761). A series of images were taken starting on Oct 24 at Oct 02:50:07 UT (~68 s after trigger). A bright optical source is detected on the first image (10s, clear filter) with r= 14.1 mag, at a position consistent with the optical afterglow reported by UVOT/Swift (Marshall et al. GCNC 28761) and MASTER (Lipunov et al. GCNC 28760).
Furthermore, from a deeper image gathered at the 1.5m OSN telescope in Observatorio de Sierra Nevada at 03:16 UT we measure R = 18.9, thus confirming the rapid fading of the optical afterglow brightness as pointed out on GCNC 28762.
Additional observations are ongoing. We thank the staff at La Mayora and OSN for their excellent support.
GCN Circular 28764
Subject
GRB 201024A: Redshift from GTC/OSIRIS
Date
2020-10-24T04:28:55Z (5 years ago)
From
Alexander Kann at IAA-CSIC <kann@iaa.es>
A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), D. A. Kann, M. Blazek,
J. F. Agui Fernandez, C. C. Thoene (all HETH/IAA-CSIC), S. Geier, and M.
Rivero (both GRANTECAN) report:
We observed the afterglow (Lipunov et al., GCN#28760, Marshall et al.,
GCN#28761, Fernandez-Garcia et al., GCN#28763) of GRB 201024A (Marshall
et al., GCN#28761) with the 10.4m GTC telescope, at Roque de los
Muchachos Observatory (La Palma, Spain) equipped with OSIRIS. The
observation started on 24 October 2020 at 03:28:47 UT (0.663 hrs after
the GRB onset) and consisted of 3 x 900 s with the R1000B grism,
covering the wavelength range between 3700 and 7800 AA. Observations
were taken under good conditions but high airmass.
At the afterglow position, a clear source is detected. We measure r' ~
19.3 mag (AB) vs. nearby PanSTARRS field stars. This indicates the
source has faded rapidly vs. the early MASTER/BOOTES detection, as
Lipunov et al., GCN#28760 and Fernandez-Garcia et al., GCN#28763 stated.
A preliminary reduction of the spectrum shows a clear continuum, with
MnII, FeII, FeII*, MgII, and MgI absorption lines, as well as the [OII]
doublet in emission, all at a common redshift of z = 0.999, which we
identify as the redshift of the GRB.
We furthermore note that there is an underlying galaxy at the OT
position visible in SDSS and PanSTARRS, at r ~ 21.15 mag. We also see a
second galaxy offset by a few arcsec in our finding chart.
We thank P. D'Avanzo and L. Izzo for pointing out the galaxy.
GCN Circular 28766
Subject
GRB 201024A: FRAM-ORM afterglow detection
Date
2020-10-24T08:56:09Z (5 years ago)
From
Martin Jelinek at Astro.Inst-AVCR,Ondrejov <martin.jelinek@asu.cas.cz>
Martin Jelinek and Jan Strobl (ASU CAS Ondrejov, CZ),
Sergey Karpov, Martin Masek, Petr Janecek, Jakub Jurysek,
Jan Ebr, Ronan Cunniffe, Petr Travnicek and Michael Prouza
(Institute of Physics, Prague, CZ)
report:
The 25cm robotic telescope FRAM-ORM at La Palma (Spain)
reacted robotically to the alert of GRB201024A (Marshall
et al GCNC 28761), obtaining a series of 20 s unfiltered
images starting at 02:49:34.4 UT, i.e. 35.3s post trigger.
We clearly detect the source reported by other telescopes
(Lipunov et al. GCN 28760, Fernandez-Garcia et al. GCN 28763,
de Ugarte Postigo et al GCN 28764 and others). As reported
before, the brightness of the object reaches a maximum of
about R(Vega) = 14.0 and then decays relatively steeply with a
power law index alpha = ~1.5.
GCN Circular 28770
Subject
GRB 201024A: Enhanced Swift-XRT position
Date
2020-10-24T11:13:17Z (5 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester)
report on behalf of the Swift-XRT team.
Using 890 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 201024A, 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 = 125.95224, +3.35444 which is equivalent
to:
RA (J2000): 08h 23m 48.54s
Dec (J2000): +03d 21' 16.0"
with an uncertainty of 2.7 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 28771
Subject
GRB 201024A: VIRT optical observations
Date
2020-10-24T15:49:18Z (5 years ago)
From
Priyadarshini Gokuldass at U. of the Virgin Islands <priyadass.94@gmail.com>
P. Gokuldass (UVI), R. Strausbaugh (UVI), N. Orange (OrangeWave Innovative
Science, LLC), D. Morris (UVI), A. Cucchiara (UVI/College of Marin) report:
We observed the field of GRB201024A (F. E. Marchall et al., GCN 28761) with
the
0.5m Virgin Island Robotic Telescope (VIRT) at the University of the Virgin
Islands' Etelman Observatory on 10-24-2020 starting at 06:39:34.2 UT (T+3.3
hrs). We performed a series of exposures in R filter with a total exposure
of 1430 s. The weather conditions were partly cloudy during the hours of
observation with an average arimass of 1.5.
We find no new source within the enhanced XRT position error circle
(P. A. Evans et al., 28770) and report the following 3-sigma upper limit:
T_mid ||Exposure ||Filter ||Limit
T+ 5 hrs ||1430s ||R ||>18.9
The limit is estimated from comparison to nearby USNO B1 stars and is not
corrected for Galactic extinction. The VIRT is still in the commissioning
phase.
This work is supported by NASA-MUREP-MIRO grant NNX15AP95A, NSF EiR AST
Award 1901296, and NSF HBCU-UP AST Award 1831682. This message can be cited.
GCN Circular 28774
Subject
GRB 201024A: Swift/UVOT Detection
Date
2020-10-25T00:02:46Z (5 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL) and F. E. Marshall (NASA/GSFC) report on
behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 201024A
495 s after the BAT trigger (Marshall et al., GCN Circ. 28761). A source
consistent with the XRT position (Evans et al. GCN Circ. 28770) is
detected in the initial UVOT exposures.
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 495 645 148 17.94 +/- 0.05
v 653 845 39 17.39 +/- 0.30
b 750 1348 58 18.65 +/- 0.32
u 726 1151 39 17.86 +/- 0.29
w1 702 1471 78 17.46 +/- 0.30
m2 677 2140 117 >18.4
w2 801 2091 117 >17.7
The observations show a rapid decay as reported by MASTER (Lipunov et al,
GCN Circ. No. 28762).
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 28775
Subject
GRB 201024A: Swift-XRT refined Analysis
Date
2020-10-25T01:18:16Z (5 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), J.P. Osborne
(U. Leicester), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) ,
M. Capalbi (INAF-IASFPA), J. D. Gropp (PSU), J.A. Kennea (PSU), A.
Tohuvavohu (U. Toronto) and F.E. Marshall report on behalf of the
Swift-XRT team:
We have analysed 6.0 ks of XRT data for GRB 201024A (Marshall et al.
GCN Circ. 28761), from 450 s to 48.0 ks after the BAT trigger. The
data are entirely in Photon Counting (PC) mode. The enhanced XRT
position for this burst was given by Evans et al. (GCN Circ. 28770).
The light curve can be modelled with a power-law decay with a decay
index of alpha=0.98 (+0.07, -0.06).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.08 (+0.19, -0.18). The
best-fitting absorption column is 1.7 (+0.6, -0.5) x 10^21 cm^-2, in
excess of the Galactic value of 3.6 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 3.3 x 10^-11 (4.6 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.7 (+0.6, -0.5) x 10^21 cm^-2
Galactic foreground: 3.6 x 10^20 cm^-2
Excess significance: 4.1 sigma
Photon index: 2.08 (+0.19, -0.18)
If the light curve continues to decay with a power-law decay index of
0.98, the count rate at T+24 hours will be 5.7 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.9 x
10^-13 (2.6 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/01001514.
This circular is an official product of the Swift-XRT team.
GCN Circular 28777
Subject
GRB201024A: rebrightening after initial steep decline
Date
2020-10-25T15:33:11Z (5 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
Paul Kuin (UCL/MSSL) reports on behalf of the Swift UVOT Team:
We now have the light curve of GRB 201024A in the seven UVOT filters
from the start of our observations T0+495s until T0+100ks. After
a steep decline a rebrightening is seen starting around T0+1400s
which then peaks between 20 and 70 ks.
GCN Circular 28778
Subject
GRB 201024A: Swift-BAT refined analysis
Date
2020-10-25T23:46:04Z (5 years ago)
From
Sibasish Laha at GSFC <sibasish.laha@nasa.gov>
T. N. Ukwatta (LANL), 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), F. E. Marshall (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), (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 201024A (trigger #1001514)
(F. E. Marshall et al., GCN Circ. 28761). The BAT ground-calculated position is
RA, Dec = 125.959, 3.357 deg which is
RA(J2000) = 08h 23m 50.3s
Dec(J2000) = +03d 21' 24.6"
with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 22%.
The BAT light curve showed a single peak structure with a duration of about 6 sec.
T90 (15-350 keV) is 5.00 +- 2.24 sec (estimated error including systematics).
The time-averaged spectrum from T+0.01 to T+6.01 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
2.10 +- 0.18. The fluence in the 15-150 keV band is 8.1 +- 0.9 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T+1.01 sec in the 15-150 keV band
is 3.7 +- 0.6 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/1001514/BA/
GCN Circular 28779
Subject
GRB 201024A: MITSuME Akeno optical upper limits
Date
2020-10-26T09:38:09Z (5 years ago)
From
Katsuhiro L. Murata at Nagoya U <murata@u.phys.nagoya-u.ac.jp>
M. Niwano, K. L. Murata, R. Hosokawa, R. Adachi, F. Ogawa, N. Nakamura, N.
Ito, S. Ogata, H. Takamatsu, H. Hara, Y. Yatsu, and N. Kawai (TokyoTech)
report on behalf of the MITSuME collaboration:
We observed the field of GRB 201024A (F. E. Marshall et al.,GCN Circular
#28761) with the optical three color (g', Rc, and Ic) CCD cameras attached
to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan.
We observed for two nights. The observation with a series of 60 sec
exposures started at 2020-10-24 16:04:04UT for the first night and
2020-10-25 15:56:17UT for the second night. We stacked the images with good
conditions each night. We did not detect the point source reported by other
telescopes (Lipunov et al. GCN Circular #28760, Fernandez-Garcia et al.
#28763, de Ugarte Postigo et al. #28764, Martin Jelinek et al. #28766). We
obtained the 5-sigma limits of the stacked images as follows.
T0+[hour] MID-UT T-EXP[sec] 5-sigma limits
------------------------------------------------------------------------------------------------
13.78 2020-10-24T18:27:11 11520 g'>20.2, Rc>20.4, Ic>19.7
38.48 2020-10-25T17:17:59 1980 g'>19.4, Rc>19.6, Ic>18.8
------------------------------------------------------------------------------------------------
T0+: Elapsed time after the burst
T-EXP: Total Exposure time
We used the 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., accepted for publication in
PASJ, https://arxiv.org/abs/2008.11486; https://github.com/MNiwano/Eclaire).
GCN Circular 28780
Subject
GRB201024A: correction to GCN28777 - there was no rebrightening
Date
2020-10-26T11:23:46Z (5 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
Paul Kuin (UCL/MSSLL) reports:
Due to an incorrect background subtraction in the later exposures of
GRB201024A, an incorrect 'rebrightening' was found in the Swift-UVOT
photometry. In actuality the source had faded away.
My sincere apologies if this has caused any problems.
GCN Circular 28782
Subject
GRB 201024A: 1.3m DFOT optical observations
Date
2020-10-26T20:10:16Z (5 years ago)
From
Rahul Gupta at ARIES, India <rahul@aries.res.in>
Rahul Gupta (ARIES), Amit Kumar (ARIES), Dimple (ARIES), Ankur Ghosh (ARIES), Amar Aryan (ARIES), Shashi B. Pandey (ARIES), and Kuntal Misra (ARIES) report:
We observed the optical afterglow ( Lipunov et al., GCN 28760; Marshall et al., GCN 28761; Fernandez-Garcia et al., GCN 28763; de Ugarte Postigo et al., GCN 28764; Jelinek et al., GCN 28766; and Kuin et al., GCN 28774 ) of Swift triggered GRB 201024A (Marshall et al., GCN 28761) using the 1.3m Devasthal Fast Optical Telescope (DFOT) at Devasthal observatory of Aryabhatta Research Institute of Observational Sciences (ARIES), India. The observations were started on 2020-10-24 at 21:03:09 UT . Multiple frames having an exposure time of 120 s were taken in R and I filters. We clearly detected the optical counterpart in the stacked images.
The preliminary photometric estimate of the afterglow in the stacked images is the following :
Date Start_UT T_start-T0 (hrs) Filter Exp time (s) Magnitude Mag_err
------------------------------ ------------------------------ ------------------------------ ------------------------------ ------------------------------------------------
2020-10-24 21:03:09 18.24 I 30*120 20.12 0.07
------------------------------ ------------------------------ ------------------------------ ------------------------------ ------------------------------------------------
The magnitude is not corrected for the Galactic and Host extinction in the direction of the burst. Photometric calibration is performed using the standard stars from the USNO-B1.0 catalog.
This circular may be cited.