GRB 241113A
GCN Circular 38194
Subject
GRB 241113A: Swift detection of a burst with an optical counterpart
Date
2024-11-13T08:28:43Z (7 months ago)
From
K.L. Page at U Leicester <klp5@leicester.ac.uk>
Via
email
M. H. Siegel (PSU), J. J. DeLaunay (PSU), P. A. Evans (U Leicester),
R. Gupta (NASA GSFC), K. L. Page (U Leicester) and T. Sakamoto (AGU)
report on behalf of the Neil Gehrels Swift Observatory Team:
At 07:48:13 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 241113A (trigger=1267501). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 16.576, -22.667 which is
RA(J2000) = 01h 06m 18s
Dec(J2000) = -22d 40' 00"
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 4 sec. The peak count rate
was ~2000 counts/sec (15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 07:49:31.0 UT, 77.2 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 16.56509, -22.67118 which is equivalent
to:
RA(J2000) = 01h 06m 15.62s
Dec(J2000) = -22d 40' 16.2"
with an uncertainty of 4.6 arcseconds (radius, 90% containment). This
location is 39 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. We
cannot determine whether the source is fading at the present time. No
spectrum from the promptly downlinked event data is yet available to
determine the column density.
UVOT took a finding chart exposure of 101 seconds with the White
filter starting 81 seconds after the BAT trigger. An uncatalogued
source is found inside the XRT error circle at
RA, Dec = 16.56518, -22.67177 which is equivalent to:
RA(J2000) = 01h 06m 15.64s
Dec(J2000) = -22d 40' 18.4"
with an estimated uncertainty of 0.7 arcseconds (radius, 90% containment).
This source is 2.1" from the centre of the XRT error circle. The estimated
magnitude of the source is 15.8.
Burst Advocate for this burst is M. H. Siegel (siegel AT swift.psu.edu).
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 38195
Subject
GRB 241113A: MASTER010615.66-224018.2 optical counterpart detection
Date
2024-11-13T08:39:27Z (7 months ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
legacy email
C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA),
V.Lipunov, I.Panchenko, A.Kuznetsov, K.Zhirkov, E.Gorbovskoy, N.Tiurina, D.Vlasenko, A.Chasovnikov, V.Topolev,
P.Balanutsa, G.Antipov, A.Sankovich,M.Gulyaev, Ya.Kechin, V.Senik (Lomonosov MSU),
A.Sosnovskij (CrAO RAS),
O.Gress, N.Budnev(ISU),
D.Buckley (SAAO),
R.Rebolo (The Instituto de Astrofisica de Canarias),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity)
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory),
MASTER Global robotic net (http://observ.pereplet.ru Lipunov et al.,2010,Advances in Astronomy,2010,30L)
started observation of Swift GRB 241113A (GCN 28194)
at MASTER-OAFA (Lipunov et al. GCN 38193, cover map https://master.sai.msu.ru/site/master2/observ.php?id=2668531 )
There is MASTER010615.66-224018.2 inside Swift error-box (GCN 38194)
with mOT~18.2 at 2024-11-13 08:02:50
observation and reduction will be continued
GCN Circular 38197
Subject
GRB241113A: LCOGT (40-cm) optical counterpart detection
Date
2024-11-13T12:46:49Z (7 months ago)
From
Ismael Perez-Fournon at Instituto de Astrofisica de Canarias <ipf@iac.es>
Via
Web form
A. Huertas Ferrer, B. Armas-Chinea, F. Dobrindt, P. Escudero-Coca, G. Fernández-Rodríguez, Á. García Lozano, C. Méndez-Lapido, I. Ortega-Casas, M. Torreiro Martínez, G. Villa (all ULL), S.R. Berlanas (IAC and ULL), and I. Pérez-Fournon (IAC and ULL)
We report on optical follow-up observations of GRB 241113A detected by Swift BAT, XRT, and UVOT (Siegel et al.; GCN circular 38194).
We observed the field of GRB 2411113A with one of the two Las Cumbres Observatory Global telescope network (LCOGT) Planewave Delta Rho 350 telescopes and QHY600 CMOS cameras located at the LCOGT node at Haleakala Observatory (Maui, Hawaii, USA) in the SDSS i' filter, in a single exposure of 600 sec. We detect a faint optical counterpart at a position consistent with the Swift UVOT detection (Siegel et al.; GCN circular 38194) with magnitude of i' = 19.48 +/- 0.35 starting at 2024-11-13 09:02:49 UT (about 1.24 hours after the Swift trigger) calibrated against the PanSTARRS DR2 catalog and without corrections for Galactic extinction.
This optical counterpart has also been detected by MASTER (Francile et al.; GCN 38195).
These results are based on observations made with the Las Cumbres Observatory’s education network
telescopes that were upgraded through generous support from the Gordon and Betty Moore Foundation,
as part of a course on Astrophysical Techniques of the Master in Astrophysics of the Universidad
de La Laguna, Tenerife, Spain (LCOGT observing programme IAC2024B-010, ULL-ASTRO-MASTER).
GCN Circular 38198
Subject
GRB 241113A: Enhanced Swift-XRT position
Date
2024-11-13T13:40:01Z (7 months ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1534 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 241113A, 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 = 16.56522, -22.67165 which is equivalent
to:
RA (J2000): 01h 06m 15.65s
Dec (J2000): -22d 40' 17.9"
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 38201
Subject
GRB 241113A: LCO optical observations
Date
2024-11-13T14:49:32Z (7 months ago)
From
luca.izzo@inaf.it
Via
Web form
L. Izzo (INAF-OACn and DARK/NBI), A. Martin-Carrillo (UCD), and D. B. Malesani (DAWN/NBI and Radboud Univ.) report:
We observed the field of GRB 241113A (Siegel et al., GCN #38194) with the Sinistro instrument mounted on the 1-m telescope of the LCO network, located at Siding Spring, Australia. Observations started on 2024 November 13 at 09:55 UT (2.17 hr after the GRB trigger). We obtained a series of 3x180 s images in the SDSS-r filter, and of 5x120 s in the PS1-z filter.
Poor telescope tracking affects individual frames, significantly disrupting the point spread function (PSF) in the stacked images. Nevertheless, in the stacked z-band image, we detect a faint source consistent with the position of the optical source reported by Swift-UVOT (Siegel et al., GCN #38194) and by other optical facilities (Francile et al., GCN #38195, Huertas Ferrer et al., GCN #38197). We measure a preliminary magnitude of z = 19.9 +/- 0.3 mag (AB), calibrated against nearby stars from the Pan-STARRS catalog. We did not detect any source at the same position in the r-band stacked image, up to a limit of ~ 20.1 mag.
This project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 101004719.
GCN Circular 38206
Subject
GRB 241113A: REM detection of the optical/NIR afterglow
Date
2024-11-13T19:34:00Z (7 months ago)
From
Matteo Ferro at INAF-OAB <matteo.ferro@inaf.it>
Via
Web form
M. Ferro, Y.-D. Hu, S. Covino, R. Brivio, P. D’Avanzo, D. Fugazza (INAF-OAB), L. Izzo (INAF-OACn and DARK/NBI), and A. Melandri (INAF-OAR) report on behalf of the REM team:
We observed the field of GRB 241113A (Siegel et al., GCN #38194; Goad et al., GCN #38198) with the REM 60cm robotic telescope located at the ESO observatory of La Silla (Chile). The observations were carried in the g, r, i, z, J, H and K bands, starting on 2024 Nov 13 at 08:03:10 UT (i.e. about 15 minutes after the Swift trigger) and lasted for about 1.75 hours.
The optical afterglow is detected in the r band at a position coincident with that reported by Swift-UVOT (Siegel et al., GCN #38194) and other optical observations (Francile et al., GCN #38195, Huertas Ferrer et al., GCN #38197; Izzo et al., GCN #38201). The NIR afterglow is detected in the H band at a position consistent with the optical counterpart.
From preliminary photometry, we derive the following magnitudes:
r = 18.7 +/- 0.3 (AB; calibrated against the Pan-STARRS catalogue)
at a mid-time of ~ 37 minutes after the trigger,
H = 15.5 +/- 0.2 (Vega; calibrated against the 2MASS catalogue)
at a mid-time of ~ 26 minutes after the trigger.
GCN Circular 38207
Subject
GRB 241113A: Swift/UVOT Detection
Date
2024-11-13T22:12:55Z (7 months ago)
From
Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk>
Via
email
A. A. Breeveld (UCL-MSSL) and M. H. Siegel (PSU) report on behalf of the Swift/UVOT team:
The Swift/UVOT began observations of the field of GRB 241113A 61 s after the BAT trigger (Siegel et al., GCN Circ. 38194) with a short settling exposure in v, and a longer finding chart exposure in the white filter.
A fading source consistent with the XRT position (Goad et al., GCN Circ. 38198) and also detected by Francile et al. (GCN Circ. 38195), Huertas Ferrer et al. (GCN Circ. 38197), Izzo et al. (GCN Circ. 38201) and Ferro et al. (GCN Circ. 38206) 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
v 61 72 11 14.87 ± 0.07
white 82 183 100 15.90 ± 0.03
b 5359 5559 197 20.18 ± 0.36
u 5154 5354 197 19.80 ± 0.33
uvw1 4949 5149 197 >19.61
uvw2 4335 5970 393 >20.12
uvm2 4744 4944 197 >19.46
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.030 in the direction of the burst (Schlegel et al. 1998).
GCN Circular 38209
Subject
GRB 241113A: Swift-XRT refined Analysis
Date
2024-11-14T00:29:13Z (7 months ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
A.P. Beardmore (U. Leicester), M. Ferro (INAF-OAB), R. Brivio
(INAF-OAB), A. D'Ai (INAF-IASFPA), J.A. Kennea (PSU), D.N. Burrows
(PSU), M. A. Williams (PSU), J.P. Osborne (U. Leicester) and P.A. Evans
report on behalf of the Swift-XRT team:
We have analysed 7.7 ks of XRT data for GRB 241113A, from 60 s to 34.4
ks after the BAT trigger. The data comprise 75 s in Windowed Timing
(WT) mode (the first 10 s were taken while Swift was slewing) with the
remainder in Photon Counting (PC) mode.
The light curve can be modelled with an initial power-law decay with an
index of alpha=1.90 (+/-0.24), followed by a break at T+165 s to an
alpha of 0.92 (+0.04, -0.05).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.32 (+0.33, -0.30). The
best-fitting absorption column is 2.2 (+1.1, -0.9) x 10^21 cm^-2, in
excess of the Galactic value of 2.0 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 3.2 x 10^-11 (5.1 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 2.2 (+1.1, -0.9) x 10^21 cm^-2
Galactic foreground: 2.0 x 10^20 cm^-2
Excess significance: 3.7 sigma
Photon index: 2.32 (+0.33, -0.30)
If the light curve continues to decay with a power-law decay index of
0.92, the count rate at T+24 hours will be 8.0 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.5 x
10^-13 (4.1 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/01267501.
This circular is an official product of the Swift-XRT team.
GCN Circular 38216
Subject
GRB 241113A: KAIT optical observations
Date
2024-11-14T09:14:38Z (7 months ago)
From
Weikang Zheng at UC Berkeley <weikang@berkeley.edu>
Via
email
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 GRB 241113A detected by Swift
(Siegel et al., GCN 38194) starting at 08:03:11 UT, 898s after
the bust under cloudy conditions. Observations were performed
in the clear (roughly R) filter, and a set of 20s, 40s and 60s
exposure images were obtained. The optical afterglow (Siegel
et al., GCN 38194; Francile et al., GCN 38195; Ferrer et al.,
GCN 38197; Izzo et al., GCN 38201; Ferro et al., GCN 38206;
Breeveld et al., GCN 38207) was barely detected in individual
image due to cloudy weather. However, the optical afterglow
was detected in the coadd images. We measure the following
magnitude calibrated to PS1 catalog:
tmid-t0(s) exp mag err
961 5x20s 17.9 +/- 0.2
1119 5x20s 18.1 +/- 0.2
1419 9x40s 18.5 +/- 0.3
2293 16x60s 19.0 +/- 0.3
GCN Circular 38217
Subject
GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
Date
2024-11-14T15:11:38Z (7 months ago)
From
Brajesh Kumar at SWIFAR, YNU <brajesh@ynu.edu.cn>
Via
Web form
Guowang Du, Brajesh Kumar, Weikang Lin, Yaosong Yu, Yehao Cheng, Yu Pan, Xinlei Chen, Xingzhu Zou, Jinghua Zhang, Yuanpei Yang, Yuan Fang, Xiangkun Liu, Xiaowei Liu (SWIFAR, YNU) report on behalf of the Mephisto Team:
The field of GRB 241113A detected by Swift (Siegel et al., GCN 38194) was observed with the 1.6m Multi-channel Photometric Survey Telescope (Mephisto) and 50cm array facilities of Yunnan University located at Lijiang Observatory. The observations were initiated after ~4.3 hr with 50cm array and Mephisto telescopes starting from 12:03:04 and 12:08:46 UT on 2024-11-13. Multiple frames (uvgriz and gr bands with Mephisto and 50 cm array) with different exposure time were obtained. The images were suffered with high background due to proximity of the moon. The optical afterglow (Siegel et al., GCN 38194; Francile et al., GCN 38195; Ferrer et al., GCN 38197; Izzo et al., GCN 38201; Ferro et al., GCN 38206; Breeveld et al., GCN 38207; Zheng et al., GCN 38216) was not detected in the stacked images and the 3-sigma upper limits are below.
50CM array
Start_Time(UT) Band Exp(s) Lim-mag(AB)
2024-11-13T12:03:05 g 120*2 >19.39
2024-11-13T12:03:04 r 120*2 >19.40
Mephisto
Start_Time(UT) Band Exp(s) Lim-mag(AB)
2024-11-13T12:08:46 u 180*4 >20.97
2024-11-13T12:26:51 v 180*2|300*2 >21.34
2024-11-13T12:08:46 g 50*12 >21.41
2024-11-13T12:26:51 r 50*6|300*2 >21.82
2024-11-13T12:08:46 i 79*8 >20.79
2024-11-13T12:26:51 z 79*4|294*2 >20.22
--------------------------------------------------------------------------
Mephisto (Multi-channel Photometric Survey Telescope) is a 1.6m wide-field multi-channel telescope, the first of its type in the world, capable of imaging the same field of view in three optical bands simultaneously. It provides real-time, high-quality colors of stellar objects. The on-site telescope assemblage and commissioning were carried out in September 2022. The first light in all three channels was achieved on 2023 December 21.
The 50cm array consists of two 50cm telescopes for wide-field surveys and also serves as the supporting facility for monitoring the Mephisto detected targets.
--------------------------------------------------------------------------
GCN Circular 38222
Subject
GRB 241113A: J-band observations with WINTER
Date
2024-11-14T19:18:17Z (7 months ago)
From
Geoffrey Mo at MIT <gmo@mit.edu>
Via
Web form
Geoffrey Mo (MIT), Tomas Ahumada (Caltech), Benjamin Schneider (MIT), Viraj Karambelkar (Caltech), Danielle Frostig (CfA), Robert Stein (UMD), Nathan Lourie (MIT), Robert Simcoe (MIT), and Mansi Kasliwal (Caltech) report:
We observed the field of GRB 241113A (Siegel et al., GCN 38194; Beardmore et al., GCN 38209) in the near-infrared J-band with the Palomar 1-m telescope, equipped with the 1-square degree WINTER camera (Lourie et al. 2020, Frostig et al. 2024).
Observations were triggered automatically and began at 2024-11-14T02:40:03 UTC (~18.9 hours after the GRB), consisting of 15 x 120 s exposures. The images were processed using the WINTER data reduction pipeline (https://github.com/winter-telescope/mirar, https://doi.org/10.5281/zenodo.13352565).
We do not detect a source at the optical and enhanced Swift/XRT counterpart location (Siegel et al., GCN 38194; Francile et al., GCN 38195; Huertas Ferrer et al., GCN 38197; Goad et al., GCN 38198; Izzo et al., GCN 38201; Ferro et al., GCN 38206; Breeveld et al., GCN 38207; Zheng et al., GCN 38216; Du et al., GCN 38217). We obtain the following 5-sigma upper limit: J ~ 18.3 mag (AB).
WINTER (Wide-field INfrared Transient ExploreR) is a partnership between MIT and Caltech, housed at Palomar Observatory, and funded by NSF MRI, NSF AAG, the David and Lucile Packard Foundation, and the MIT Kavli Institute for Astrophysics and Space Research.
GCN Circular 38227
Subject
GRB 241113A: PRIME near-infrared upper limits
Date
2024-11-15T00:00:26Z (6 months ago)
From
Joe Durbak at UMD <gcn.joedurbak@gmail.com>
Via
Web form
J. Durbak (UMD), O. Guiffreda (UMD), A. S. Kutyrev (NASA/GSFC), E. Troja (U Rome), S. B. Cenko (NASA/GSFC)
Following the Swift BAT detection (GCN 38194), we observed the transient field in J and H filters with PRIME ~13 hours after Swift BAT detection.
At the counterpart positions reported by Swift XRT and UVOT and (GCN 38194, GCN 38198), LCOGT (GCN 38197), LCO (GCN 38201) and KAIT (GCN 38216), we detect no uncatalogued sources in J-band. Using nearby VISTA Hemispherical Survey (VHS) stars for preliminary calibration we derive a limiting magnitude of <20.4 AB. We also detect no uncatalogued sources in H-band. Using nearby 2MASS stars for preliminary calibration we derive a limiting magnitude of <20.6 AB. Neither of these results are corrected for Galactic extinction.
PRIME is a 1.8m telescope with 1.56 square degree FOV (0.5 arcsec/pixel) located in Sutherland, South Africa at the South African Astronomical Observatory (SAAO) (Kutyrev et al. 2023, Yama et al. 2023, Durbak et al. 2024).
We thank the Osaka University observers at PRIME and the staff at SAAO for their support with these observations.
GCN Circular 38229
Subject
GRB 241113A: Swift-BAT refined analysis
Date
2024-11-15T03:13:37Z (6 months ago)
From
Takanori Sakamoto at AGU <tsakamoto@phys.aoyama.ac.jp>
Via
Web form
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), R. Gupta (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa),
C. B. Markwardt (GSFC), M. J. Moss (GSFC), D. M. Palmer (LANL),
T. Parsotan (GSFC), D. Sadaula (GSFC/UMBC), T. Sakamoto (AGU), M. H. Siegel (PSU)
(i.e. the Swift-BAT team):
Using the data set from T-239 to T+329 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 241113A (trigger #1267501)
(Siegel, et al., GCN Circ. 38194). The BAT ground-calculated position is
RA, Dec = 16.578, -22.658 deg which is
RA(J2000) = 01h 06m 18.7s
Dec(J2000) = -22d 39' 27.8"
with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 93%.
The mask-weighted light curve shows a single-pulse structure that starts at
T0, peaks at T+0.5 sec, and ends at T+2 sec. There is a hint of the emission
between T+35 sec and T+80 sec. T90 (15-350 keV) is 1.7 +- 0.4 sec
(estimated error including systematics).
The time-averaged spectrum from T+0.01 to T+2.06 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.76 +- 0.23. The fluence in the 15-150 keV band is 1.3 +- 0.2 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.00 sec in the 15-150 keV band
is 1.4 +- 0.2 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/1267501
GCN Circular 38287
Subject
GRB 241113A: Possible ATCA Radio detection
Date
2024-11-21T02:50:29Z (6 months ago)
From
Gemma Anderson at Curtin U <gemma.anderson@curtin.edu.au>
Via
Web form
G. E. Anderson (Curtin), S. Chastain (UNM), J. K. Leung (UofT/HUJI), A. J. van der Horst (GWU), L. Rhodes (TSI/McGill), A. Gulati (USyd), B. Gompertz (Birmingham) on behalf of the ATCA PanRadio GRB collaboration
The Australia Telescope Compact Array (ATCA) rapid-response mode triggered on GRB 241113A (Siegel et al. GCN 38194) 2024-11-13. The observation start time was delayed due to poor weather conditions so began 2.6 hours post-burst (10:25-17:30 UT). We tentatively detect the radio afterglow coincident with the X-ray (Siegel et al. GCN 38194, Goad et al. GCN 38198) and optical position (Siegel et al. GCN 38194, Francile et al. GCN 38195, Huertas Ferrer et al. GCN 38197, Izzo et al. GCN 38201, Ferro et al. GCN 38206, Zheng et al. GCN 38216) at 9 GHz with a flux density of 42+/-16 microJy/beam (RMS of 10 microJy/beam).
We thank the CSIRO Space and Astronomy staff for supporting these observations.
We acknowledge the Gomeroi people as the traditional owners of the Observatory site. The Australia Telescope Compact Array is part of the Australia Telescope National Facility (https://ror.org/05qajvd42) which is funded by the Australian Government for operation as a National Facility managed by CSIRO.
GCN Circular 38658
Subject
GRB241113A: 7DT Optical upper limits
Date
2024-12-24T02:03:11Z (5 months ago)
From
Gregory Paek at Seoul National University <gregorypaek94@gmail.com>
Via
Web form
Gregory S.H. Paek (SNU ARC/SNU), Myungshin Im (SNU ARC/SNU), Hyeonho Choi (SNU ARC/SNU), Seo-Won Chang (SNU ARC/SNU), and Ji Hoon Kim (SNU ARC/SNU) report on behalf of the 7-Dimensional Telescope collaboration
We searched for the optical counterpart of the GRB, GRB241113A (Siegel et al., GCN #38194) using the 7-Dimensional Telescopes (7DT). Approximately 18.8 hours following the initial detection (2024-11-13T07:48:13 UTC), we targeted the localization center provided by the Swift UVOT at RA, Dec = 16.56518 deg, -22.67177 deg with an uncertainty of 0.7 arcsecs. Observations were made with eleven 7DT units in twenty medium-band filters, denoted as m400, m425, then through m875, in which the numeric values indicate their central wavelengths in nanometers. Each medium-band filter has a bandwidth of 25nm.
No significant transient event was identified in the preliminary result. Photometric flux calibration was performed using synthetic photometries derived from the Gaia DR3 XP catalog (Gaia Collaboration et al. 2022) within the AB magnitude system. The 5-sigma upper limits (AB) range from 16.8 to 19.0 mag in the medium-band filters. To improve the depth for detection, we combined all images taken with the medium-band filters from m400 to m875. The combined image was treated as an r-band equivalent, and photometric measurements were performed. This approach yielded a 5-sigma upper limit of 19.7 AB magnitudes. Despite the increased depth, no significant transient detection was identified. Observations were conducted under suboptimal conditions, potentially limiting our search sensitivity.
------
Filter Date-obs[UT] Exp.time[s] Depth(5sigma)
m400 2024-11-14T02:42:18 300 18.526
m425 2024-11-14T02:42:16 300 18.738
m450 2024-11-14T02:36:44 300 18.467
m475 2024-11-14T02:42:15 300 18.638
m500 2024-11-14T02:36:43 300 18.849
m525 2024-11-14T02:42:11 300 18.995
m550 2024-11-14T02:36:47 300 18.534
m575 2024-11-14T02:42:16 300 18.614
m600 2024-11-14T02:36:50 300 18.560
m625 2024-11-14T02:42:26 300 18.515
m650 2024-11-14T02:36:47 300 18.248
m675 2024-11-14T02:42:15 300 18.171
m700 2024-11-14T02:36:46 300 18.075
m725 2024-11-14T02:42:15 300 17.918
m750 2024-11-14T02:36:45 300 17.930
m775 2024-11-14T02:42:16 300 17.723
m800 2024-11-14T02:35:00 600 17.669
m825 2024-11-14T02:40:32 600 17.552
m850 2024-11-14T02:36:47 300 16.957
m875 2024-11-14T02:36:47 300 16.841
The 7-Dimensional Telescope (7DT), located in Chile and comprising 20 wide-field telescopes equipped with 40 medium-bandwidth (~25nm) filters, aims to detect optical counterparts of GW sources and conduct the 7-Dimensional Sky Survey (7DS) of the Southern Hemisphere. Further information about the 7DT is available at http://gwuniverse.snu.ac.kr/.