GRB 250702F
GCN Circular 41082
Subject
GRB 250702F: Swift-BAT refined analysis
Date
2025-07-13T21:00:20Z (a month ago)
From
Takanori Sakamoto at AGU <tsakamoto@phys.aoyama.ac.jp>
Via
Web form
M. J. Moss (GSFC), S. D. Barthelmy (GSFC), R. Gupta (GSFC),
N. J. Klingler (GSFC/UMBC/CRESSTII) H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Parsotan (GSFC), D. Sadaula (GSFC/UMBC), T. Sakamoto (AGU)
(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 250702F (trigger #1329888)
(Klingler, et al., GCN Circ. 40894). The BAT ground-calculated position is
RA, Dec = 212.942, 16.739 deg which is
RA(J2000) = 14h 11m 46.1s
Dec(J2000) = +16d 44' 20.6"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 81%.
The mask-weighted light curve shows a complex structure that starts at
~T-3 s, peaks at ~T+38 s, and ends at ~T+80 s.
T90 (15-350 keV) is 63.7 +- 12.5 sec (estimated error including systematics).
The time-averaged spectrum from T-29.13 to T+76.44 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.49 +- 0.06. The fluence in the 15-150 keV band is 4.8 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+37.35 sec in the 15-150 keV band
is 5.1 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
The results of the batgrbproduct analysis are available at
https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1329888
GCN Circular 41023
Subject
GRB 250702F: radio detection with the VLA
Date
2025-07-08T12:10:37Z (2 months ago)
From
Stefano Giarratana at INAF-OAB <s.giarratana@ira.inaf.it>
Via
email
S. Giarratana (INAF-OAB), M. Giroletti (INAF-IRA),
G. Ghirlanda (INAF-OAB), N. Di Lalla (Stanford Univ.),
N. Omodei (Stanford Univ.), O. S. Salafia (INAF-OAB),
L. Nava (INAF-OAB)
At 02:54:00 UT on 2025 July 6 (T_mid = 3.27 days post-burst)
the Karl G. Jansky VLA observed the field of GRB 250702F
(Fermi GBM team, GCN 40892; Klingler et al., GCN 40894;
Frederiks et al., GCN 40948) in three bands, with central
frequencies of 6, 10 and 15 GHz.
The standard 3C286 was used as bandpass and flux density
calibrator, while J1415+1320 was used as phase calibrator.
From a preliminary analysis, an unresolved radio source
is detected at a position (J2000):
RA: 14:11:44.641 +- 0.004
Dec: +16:44:54.68 +- 0.06
consistent with the X-ray (Goad et al., GCN 40902;
Liang et al., GCN 40967) and optical (Klingler et al.,
GCN 40894; Jelinek et al., GCN 40895; Kumar et al., GCN 40896;
Lipunov et al., GCN 40899; Martin-Carrillo et al., GCN 40900;
de Ugarte Postigo et al., GCN 40901; Angulo et al., GCN 40907;
Becerra et al., GCN 40911; Brivio et al., GCN 40913; An et al.,
GCN 40916; Dutton et al., GCN 40921; Odeh et al., GCN 40925;
Moretti et al., GCN 40926; Siegel et al., GCN 40933; Ma et al.,
GCN 40936; Vinko et al., GCN 40939; Mohan et al., GCN 40946;
Ciabattari et al., GCN 40968; Broens et al., GCN 40969;
Calapai et al., GCN 40973; Antier et al., GCN 41011) position
of the transient.
The preliminary analysis yields the following results:
================================================================
T_mid Freq Peak r.m.s. Beam PA
[days] [GHz] [uJy/b] [uJy/b] [arcsec^2] [deg]
================================================================
3.27 6 158 7 3.31x3.03 22
3.27 10 127 6 2.09x1.95 31
3.27 15 141 7 1.39x1.26 1
================================================================
We would like to thank the staff of the VLA for approving, executing,
and processing the observations.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc.
These observations were carried out as part of project SF171028,
approved in the framework of the Fermi - NRAO joint program agreement.
GCN Circular 41011
Subject
GRB 250702F: GRANDMA observations
Date
2025-07-07T16:38:26Z (2 months ago)
From
Sarah Antier at OCA <sarah.antier@oca.eu>
Via
Web form
S. Antier (OCA/IJCLAB), S. Karpov (FZU), E. de Bruin (UMN), N. Kochiashivili (AbAO), M. Lamoureux (Uliege), T. Du Laz (Caltech), A. Klotz (IRAP), C. Limonta (OCA) on behalf of GRANDMA:
We observed the field of GRB 250702F (Fermi GBM team, GCN 40892; Klingler et al., GCN 40894) with TAROT and Kilonova catcher (GCN 40969), 1.72 min post T0 and obtained optical counterpart detection.
All our measurements are made public and can be downloaded in order to support the Swift and Fermi/GBM GRB science: https://skyportal-icare.ijclab.in2p3.fr/public/sources/GRB-250702_210643/version/9d4e549b1a3ed2535aae7b1392c94c2c
All the data have been reduced by a single data processing pipeline, STDPipe (Karpov et al., 2025). Images obtained with the sloan filters were calibrated using the PanSTARRS DR1 catalog. Images obtained with the Johnson-cousins filters were calibrated using the GAIA DR3 synphot catalog.
We use the SkyPortal application (skyportal.io) to monitor our observational campaign (Coughlin et al. 2023).
Our observations are consistent with other already reported (see the Skyportal page) Jelinek et al. (GCN 40895); Kumar et al. (GCN 40896); Lipunov et al. (GCN 40898); Martin-Carrillo et al. (GCN 40900); Angulo et al. (GCN 40907); Becerra et al. (GCN 40911); Brivio et al. (GCN 40913); An et al. (GCN 40916); Dutton et al. (GCN 40921); Odeh et al. (GCN 40925); Moretti et al. (GCN 40926); Siegel et al. (GCN 40933); Ma et al. (GCN 40936); Vinko et al. (GCN 40939); Mohan et al. (GCN 40946); Ciabattari et al. (GCN 40968).
GRANDMA is a worldwide 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/).
Skyportal/ICARE is supported by ACME.
GCN Circular 40973
Subject
GRB 250702F: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
Date
2025-07-05T11:42:59Z (2 months ago)
From
Giovanni Calapai at Calapai Astronomical Observatory, Massa S. Giorgio, Messina, Italy <giovannicalapai@tiscali.it>
Via
Web form
Giovanni Calapai at Calapai Astronomical Observatory, Massa S. Giorgio, (Messina) Italy
Member of: GRB/UAI Gamma Ray Burst Section of Unione Astrofili Italiani.
Report:
We observed the field of GRB 250702F detected by Swift/BAT (Klingler et al., GCN 40894) and Fermi/GBM (Fermi GBM Team, GCN 40892) with the 11 inches Schmidt-Cassegrain (Celestron 11) telescope F/D=6,3.
The observations were started at 2025-07-02 21:32:30 UT (approximately 0.43 hours after burst) stacking two consecutive sets of unfiltered CCD image. The observations were carried out with clear skies and good visibility conditions.
The OT was detected at the following position:
RA (J2000.0) 14h 11m 44.68s
Decl. (J2000.0) +16° 44' 55.0"
Photometry was obtained using nearby PanSTARRS stars as follows:
Observation Mid-Time T-T0 (hr) Exposure Filter Mag. Mag. err.
2025-07-02 22:03:02 UT 0.94 60x60s CR 17.13 +/-0.02
2025-07-02 23:05:09 UT 1.97 60x60s CR 18.07 +/-0.05
Magnitude was calibrated with the nearby PanSTARRS stars converted using Lupton (2005) equations.
No correction for galactic dust extinction was applied.
Our observations are consistent with other already reported Jelinek et al. (GCN 40895); Kumar et al. (GCN 40896); Lipunov et al. (GCN 40898); Martin-Carrillo et al. (GCN 40900); Angulo et al. (GCN 40907); Becerra et al. (GCN 40911); Brivio et al. (GCN 40913); An et al. (GCN 40916); Dutton et al. (GCN 40921); Odeh et al. (GCN 40925); Moretti et al. (GCN 40926); Siegel et al. (GCN 40933); Ma et al. (GCN 40936); Vinko et al. (GCN 40939); Mohan et al. (GCN 40946); Ciabattari et al. (GCN 40968); Broens et al. (GCN 40969).
The message may be cited.
GCN Circular 40969
Subject
GRB 250702F: Kilonova-Catcher optical afterglow detection
Date
2025-07-05T07:49:37Z (2 months ago)
From
Damien Turpin at CEA-Saclay <dturpin-astro@hotmail.com>
Via
Web form
E. Broens, M. Freeberg, R. Hellot (KNC), D. Turpin (CEA-Saclay/Irfu), C. Andrade(UMN), M. Pillas (ULiege), M. Tanasan (NARIT), S. Antier (OCA/IJCLAB) on behalf of the GRANDMA/Kilonova-Catcher collaboration:
We observed the field of GRB 250702F (Fermi GBM team, GCN 40892; Klingler et al., GCN 40894) with the GRANDMA citizen science project Kilonova-catcher (KNC). Our observations were performed with the T-BRO telescope operated by E. Broens and the CDK17 telescope located at AITP San Pedro Chile Observatory operated by R. Hellot, the iTelescope T72 and TEC180FL telescope operated by M. Freeberg and the 14SC telescope operated by M Odeh. Our observations started at TGRB+1.8hr.
In our stacked frames, subtracted from the PanSTARRS DR2 template image, we detect the optical counterpart reported by Swift/UVOT (Klingler et al., GCN 40894, Siegel et al., GCN 40933) and further confirmed by many other teams (Jelinek et al.,GCN 40895; Kumar et al., GCN 40896; Lipunov et al., GCN 40899; Martin-Carrillo et al., GCN 40900; de Ugarte Postigo et al., GCN 40901; Angulo et al., GCN 40907; Becerra et al., GCN 40911; Brivio et al., GCN 40913; An et al., GCN 40916; Dutton et al., GCN 40921; Odeh et al., GCN 40925; Moretti et al., GCN 40926; Ma et al., GCN 40936; Vinko et al., GCN 40939; Mohan et al., GCN 40946)
We report some of our first image follow-up results in the table below:
+---------------+-----------+------------+---------------+------------|
| Tmid-TGRB (hr)| Exp (s) | Filter | Magnitude | Instrument |
+===============+===========+============+===============+============+
| 1.9 | 5 x 180s | R (Vega) | 18.11 +/- 0.08 | T-BRO |
| 2.8 | 300s | sdssr (AB) | 18.45 +/- 0.07 | CDK17-AITP|
| 3.8 | 300s | sdssg (AB) | 19.01 +/- 0.08 | CDK17-AITP|
| 3.2 | 10 x 180s | R (Vega) | 18.56 +/- 0.06 | iT72 |
| 7.1 | 16 x 180s | sdssr (AB) | 19.54 +/- 0.15 | TEC180FL |
+---------------+-----------+------------+----------------+-----------+
All the data have been reduced by a single data processing pipeline, STDPipe (Karpov et al., 2022). Images obtained with the sloan filters were calibrated using the PanSTARRS DR1 catalog. Images obtained with the Johnson-cousins filters were calibrated using the GAIA DR3 synphot catalog.
We use the SkyPortal application (skyportal.io) to monitor our observational campaign (Coughlin et al. 2023).
GRANDMA is a worldwide 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 40968
Subject
GRB 250702F: Monte Agliale Observatory optical observations
Date
2025-07-05T06:56:14Z (2 months ago)
From
Fabrizio Ciabattari at Monte Agliale Observatory <fabciaba@alice.it>
Via
Web form
F. Ciabattari, S. Donati, G. Fornaciari, S. Guidotti, E. Mazzoni, M. Rossi, R. Simonetti, R. Bernacchi, F. Biagini, R. Gemignani, M. Giovannini and G. Petroni (Monte Agliale Observatory, Borgo a Mozzano, Italy) report:
We observed the field of GRB 250702F (Klingler et al. GCN 40894