GRB 221024A
GCN Circular 32827
Subject
GRB 221024A: Swift detection of a burst
Date
2022-10-24T13:23:22Z (3 years ago)
From
Jamie Kennea at Penn State U <jak51@psu.edu>
R. Brivio (INAF-OAB), P. D'Avanzo (INAF-OAB), M. Ferro (INAF-OAB),
J.D. Gropp (PSU), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL),
S. Laha (GSFC/UMBC), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester), D. M. Palmer (LANL),
T. M. Parsotan (GSFC/UMBC/CRESSTII), T. Sbarrato (INAF-OAB),
B. Sbarufatti (INAF-OAB), M. H. Siegel (PSU) and M. A. Williams (PSU)
report on behalf of the Neil Gehrels Swift Observatory Team:
At 13:00:27 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 221024A (trigger=1131029). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 169.718, +33.041 which is
RA(J2000) = 11h 18m 52s
Dec(J2000) = +33d 02' 28"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a single-peaked
structure with a duration of about 30 sec. The peak count rate
was ~1000 counts/sec (15-350 keV), at ~3 sec after the trigger.
The XRT began observing the field at 13:02:36.5 UT, 129.5 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 169.74060, 33.04207 which is equivalent
to:
RA(J2000) = 11h 18m 57.74s
Dec(J2000) = +33d 02' 31.5"
with an uncertainty of 3.5 arcseconds (radius, 90% containment). This
location is 68 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 in excess of the Galactic value (2.86 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 4
(+2.22/-1.98) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 250 seconds with the UVW2 filter
starting 127 seconds after the BAT trigger. No credible afterglow
candidate has been found in the initial data products. The 2.7'x2.7'
sub-image processing failed because there is no aspect solution due
to a nearby very bright star. Results from the list of sources
generated on-board are not available at this time.
Burst Advocate for this burst is R. Brivio (riccardo.brivio AT inaf.it).
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 32838
Subject
GRB 221024A: D50 candidate afterglow
Date
2022-10-25T04:28:46Z (3 years ago)
From
Martin Jelinek at Astro.Inst-AVCR,Ondrejov <martin.jelinek@asu.cas.cz>
Jan Strobl, Martin Jelinek, Rene Hudec, Cyril Polasek
Astronomical Institute of the Academy of Sciences (ASU CAS), Ondrejov
report
With the 0.5m robotic telescope located in Ondrejov, we observed the
position of the Swift rigger 1131029 or GRB 221024A (Brivio et al, 32827),
starting at October 25, 3:18UT, i.e. 14.25h post GRB. In the series of
unfiltered 60s exposures, we detect an uncatalogued source inside the XRT
error box. The preliminary magnitude of this source is ~19.1+-0.1, the
photometry is complicated by the presence of the star nu UMa in the
proximity of the field.
GCN Circular 32839
Subject
GRB 221024A: Enhanced Swift-XRT position
Date
2022-10-25T06:08:21Z (3 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 3710 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 221024A, 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 = 169.74062, +33.04199 which is equivalent
to:
RA (J2000): 11h 18m 57.75s
Dec (J2000): +33d 02' 31.2"
with an uncertainty of 2.6 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 32841
Subject
GRB 221024A: GIT confirmation of the optical afterglow
Date
2022-10-25T09:04:49Z (3 years ago)
From
Harsh Kumar at Indian Inst of Tech,Bombay <harshkosli13@gmail.com>
V. Swain (IITB), H. Kumar (IITB), A. Kaysang (IAO), V. Bhalerao (IITB), G.
C. Anupama(IIA) and S. Barway (IIA) report on behalf of the GIT team:
We observed GRB 221024A detected by Swift-BAT (R. Brivio et al., GCN
#32827) with 0.7m GROWTH-India Telescope (GIT). We obtained multiple 300s
exposures in the r' filter and clearly detected the afterglow in our image
at R.A.= 11:18:57.78 DEC = +33:02:30.64. The photometric results follow as:
--------------------------------------------------------------------
JD (Start) | T_Start-T0(hrs) | Filter | Magnitude (AB) |
--------------------------------------------------------------------
2459877.42179 | 9.12 | r' | 18.36 +/- 0.05 |
2459877.45883 | 10.00 | r' | 18.50 +/- 0.1 |
--------------------------------------------------------------------
GIT photometry and results from Jan Strobl et al. (GCN #32838) conclude
that the source is fading and is an afterglow of GRB 221024A. The
magnitudes are calibrated against PanSTARRS DR1 (Chambers et al., 2016) and
not corrected for Galactic extinction.
The GROWTH India Telescope (GIT; Kumar et al. 2022
<https://iopscience.iop.org/article/10.3847/1538-3881/ac7bea>) is a 70-cm
telescope with a 0.7-degree field of view, set up by the Indian Institute
of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB)
with funding from DST-SERB and IUSSTF. It is located at the Indian
Astronomical Observatory (Hanle), operated by IIA. We acknowledge funding
by the IITB alumni batch of 1994, which partially supports the operations
of the telescope. Telescope technical details are available at
https://sites.google.com/view/growthindia/.
GCN Circular 32846
Subject
GRB 221024A: Swift-XRT refined Analysis
Date
2022-10-25T14:30:17Z (3 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC &
INAF-OAR), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), D.N. Burrows
(PSU), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P.A.
Evans (U. Leicester) and R. Brivio report on behalf of the Swift-XRT
team:
We have analysed 6.0 ks of XRT data for GRB 221024A (Brivio et al. GCN
Circ. 32827), from 114 s to 52.5 ks after the BAT trigger. The data
comprise 248 s in Windowed Timing (WT) mode (the first 8 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Osborne et
al. (GCN Circ. 32839).
The late-time light curve (from T0+11.3 ks) can be modelled with a
power-law decay with a decay index of alpha=1.61 (+0.20, -0.21).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.53 (+/-0.04). The
best-fitting absorption column is 5.4 (+/-1.1) x 10^20 cm^-2, in
excess of the Galactic value of 2.9 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.96 (+0.14, -0.13)
and a best-fitting absorption column of 6.0 (+3.2, -2.9) x 10^20 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 3.3 x 10^-11 (3.7 x 10^-11) erg cm^-2
count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 6.0 (+3.2, -2.9) x 10^20 cm^-2
Galactic foreground: 2.9 x 10^20 cm^-2
Excess significance: 1.7 sigma
Photon index: 1.96 (+0.14, -0.13)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01131029.
This circular is an official product of the Swift-XRT team.
GCN Circular 32848
Subject
GRB 221024A: Swift/UVOT UV upper limits
Date
2022-10-25T14:54:44Z (3 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin and R. Brivio report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB221024A
127 seconds after the BAT trigger (Brivio et al., GCN Circ. 32827).
The UVOT could not observe in the u,b,v or white filters due to the
nearby bright star nu uMa (V=3.49, U=6.44). A source detection has
been reported by Strobl et al. (GCN Circ. 32838) and by Swain et al.
(GCN Circ. 32841) with r' = 18.36 at 9.12 hours after the Trigger.
UVOT obtained images in uvw1, uvm2 and uvw2. Visual inspection shows
no credible source in the initial images with upper limits of 19.7 mag.
In the uvm2 filter which has no red leak we obtained deeper limits:
filter tstart(s) tstop(s) exposure 3-sigma UL
uvm2 23992 36065 609 >21.3
uvm2 51885 52503 3306 >20.3
The limits in the UV are about 3 mag. below the reported detections
in r', which may suggest a redshift larger than 1.5.
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.05 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 32854
Subject
GRB 221024A: Swift-BAT refined analysis
Date
2022-10-26T14:47:54Z (3 years ago)
From
Hans Krimm at NSF/NASA-GSFC <hkrimm@nsf.gov>
A. Y. Lien (U Tampa), S. D. Barthelmy (GSFC), R. Brivio (INAF-OAB),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU),
M. Stamatikos (OSU) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 221024A (trigger #1131029)
(Brivio, et al., GCN Circ. 32827). The BAT ground-calculated position is
RA, Dec = 169.702, 33.068 deg which is
RA(J2000) = 11h 18m 48.6s
Dec(J2000) = +33d 04' 04.9"
with an uncertainty of 2.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 35%.
The mask-weighted light curve shows a rather weak pulse starting at the trigger
time, peaking around T+5 seconds and decaying to baseline by about T+40 seconds.
There is some low-level emission following this peak, including a possible peak
In the low-energy bands at approximately T+200 seconds. The pipeline-calculated
T90 (15-350 keV) is 120+-111 sec (estimated error including systematics), with the
large stated error due to uncertainty in whether the possible T+200 peak contains
at least 5% of the burst fluence.
The time-averaged spectrum from T+0.00 to T+221.28 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.39 +- 0.25. The fluence in the 15-150 keV band is 1.5 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+2.93 sec in the 15-150 keV band
is 1.5 +- 0.3 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/1131029/BA/
GCN Circular 32859
Subject
GRB 221024A: GRANDMA observations
Date
2022-10-26T21:06:19Z (3 years ago)
From
Cristina Andrade at UMN <andra104@umn.edu>
C. Andrade (UMN), A. Iskandar (XAO), A. Klotz (IRAP-OMP), H. Peng (THU),
T. Sadibekova (AIM-CEA), M.Trevor (UMD), M. Freeberg (KNC),
D. Turpin (CEA), S. Antier (OCA/Artemis), A. Benkhaldoun (HAO),
S. Alishov(ShAO), E. Gurbanov(ShAO), E. Hesenov (ShAO), A. Kaeouach (HAO),
N. Kochiashvili (ShAO) K. Noysena (TRT), F.Guo(THU), Y.Rajabov (UBAI),
N. Sasaki (OPD), Z. Vidadi (ShAO),
report on behalf of the GRANDMA collaboration:
The GRANDMA telescope network responded to the Swift-BAT alert of
GRB 221024A (R. Brivio et al., GCN 32827, J.P. Osborne et al. GCN 32839,
M. Capalbi et al. GCN 32846, A. Y. Lien et al. GCN 32854),
which is also detected by Fermi (J. Wood et al. GCN 32835).
The first observations started 22 hours after the BAT trigger time.
The afterglow was reported detected within
the XRT enhanced error region by different teams: J. Strobl et al.
(GCN 32838) D50-telescope from ASU CAS; V. Swain et al. (GCN 32841)
0.7m GROWTH India Telescope; including UVOT observations and
N. P. M. Kuin et al. (GCN 32848).
In the following table we report the preliminary photometry of our
observations. Upper limits are reported at the 5-sigma limit,
in the AB system.
T-T0 (hr)| MJD | Observatory| Filter | Upp.Mag.
____________________________________________________
22.11 |59877.463197| KNC-NMSkies | ps1/r | 19.7
Most of the sites were limited by the sky visibility and the weather
conditions. There is also light pollution from the nearby bright star
(Nu UMa, apparent mag (V) +3.490) located at ~6' from the XRT position.
Only one observation was successfully performed in the context of the
Kilonova-Catcher programme (KNC), a professional-amateur collaboration
within the GRANDMA project, by the T21 New Mexico skies iTelescope using
filter ps1/r. The KNC image have been processed using the STDpipe and
photometry was performed using field stars from the PanSTARRS1-r catalogue
as reference.
GRANDMA is a worldwide coordinated telescope network
(grandma.ijclab.in2p3.fr) devoted to the observation of transients
in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS
497, 5518). Kilonova-Catcher (KNC) is the citizen science program of
GRANDMA (http://kilonovacatcher.in2p3.fr/).
GCN Circular 32863
Subject
GRB 221024A: Mondy optical observations
Date
2022-10-27T12:17:13Z (3 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), A. Pozanenko (IKI), E. Klunko (ISTP), N. Pankov (HSE) report on behalf of IKI-GRB-FuN:
We observed the field of GRB 221024A (Swift: Brivio et al., GCN 32827; Fermi: J. Wood et al. GCN 32835 ) with AZT-33IK telescope of Mondy observatory starting on Oct. 26 (UT) 21:03:08. In the stacked image we detected the optical counterpart (Strobl et al., GCN 32838, Swain et al., GCN 32841, Andrade et al., GCN 32859) in coordinates (J2000) 11:18:57.58, +33:02:32.1 with uncertainities of 0.14 arcsec in both coordinates. The position of the optical counterpart is 2.3" apart from the center and within of the enhanced XRT position (Osborne et al., GCN 32839). Preliminary photometry of the field is following.
Date UT start t-T0 Filter Exp. OT Err. UL(3sigma)
(mid, days) (s)
2022-10-26 21:03:08 2.35534 R 29*120 21.0 0.1 22.5
Photometry is based on the USNO-B2.0 nearby stars.
USNO-B1.0
RA DEC R2
11:18:51.3907200 +32:59:13.401600 16.52
11:19:04.3800000 +32:58:07.082400 17.00