GRB 240529A
GCN Circular 36556
Subject
GRB 240529A: Swift detection of a burst with an optical counterpart
Date
2024-05-29T03:38:03Z (a year ago)
From
David Palmer at LANL <palmer@lanl.gov>
Via
email
R. A. J. Eyles-Ferris (U Leicester), R. Gupta (NASA/GSFC),
A. Y. Lien (U Tampa), K. L. Page (U Leicester), D. M. Palmer (LANL)
and T. M. Parsotan (GSFC) report on behalf of the Neil Gehrels Swift
Observatory Team:
At 02:58:31 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 240529A (trigger=1231488). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 335.322, +51.555 which is
RA(J2000) = 22h 21m 17s
Dec(J2000) = +51d 33' 19"
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 at least 20 sec since we are missing data
after ~8 sec. The peak count rate was ~4000 counts/sec (15-350 keV),
at ~0 sec after the trigger.
The XRT began observing the field at 03:06:22.0 UT, 471.2 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source located at RA, Dec 335.35696, 51.56207 which
is equivalent to:
RA(J2000) = 22h 21m 25.67s
Dec(J2000) = +51d 33' 43.5"
with an uncertainty of 3.5 arcseconds (radius, 90% containment). This
location is 82 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 4.06
x 10^21 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 128 seconds after the BAT trigger. There is a candidate afterglow in
the list of sources generated on-board at
RA(J2000) = 22:21:26.04 = 335.35851
DEC(J2000) = +51:33:43.4 = 51.56205
with a 90%-confidence error radius of about 1.10 arc sec. This position is 2.7
arc sec. from the center of the XRT error circle. The estimated magnitude is
17.84. No correction has been made for the large, but uncertain, extinction
expected.
Burst Advocate for this burst is R. A. J. Eyles-Ferris (raje1 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 36557
Subject
GRB 240529A: Enhanced Swift-XRT position
Date
2024-05-29T05:48:24Z (a year ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1384 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 240529A, 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 = 335.35741, +51.56166 which is equivalent
to:
RA (J2000): 22h 21m 25.78s
Dec (J2000): +51d 33' 42.0"
with an uncertainty of 2.2 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 36559
Subject
GRB 240529A: GOTO optical afterglow detection
Date
2024-05-29T07:47:25Z (a year ago)
From
Amit Kundu at University of Warwick, UK <amitkundu515@gmail.com>
Via
Web form
A. Kumar, B. P. Gompertz, S. Belkin, G. Ramsay, Y. Julakanti, R. Starling, K. Ackley, M. J. Dyer, J. Lyman, K. Ulaczyk, F. Jimenez-Ibarra, D. O'Neill, D. Steeghs, D. K. Galloway, V. Dhillon, P. O'Brien, K. Noysena, R. Kotak, R. P. Breton, L. K. Nuttall, E. Palle and D. Pollacco report on behalf of the GOTO collaboration:
The Gravitational-wave Optical Transient Observer (GOTO, Steeghs et al., 2022) performed targeted observations in response to Swift-detected GRB 240529A (Eyles-Ferris et al., GCN 36556). Three epochs of targeted observations were performed by GOTO-North starting at 2024-05-29UT03:02:10.4 (3.67 minutes after the trigger). The first two targeted observations consisted of 4x90s exposures in the GOTO L-band (400-700 nm), whereas the third pointing was covered during the serendipitous survey pointing and had exposure times of 4x45 sec.
We detect the optical afterglow in all three epochs, with L-band magnitudes of 16.06 +/- 0.01, 17.55 +/- 0.03 and 17.30 +/- 0.04 at 4.5 minutes, 1.22 hours and 1.72 hours (mid-points) after trigger, respectively.
Magnitudes were calibrated using ATLAS-REFCAT2 (Tonry et al. 2018) and are not corrected for Galactic extinction.
GOTO (https://goto-observatory.org) is a network of telescopes that is principally funded by the STFC and operated at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia, on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), the University of Turku, the University of Portsmouth, the University of Manchester and the Instituto de Astrofisica de Canarias (IAC).
GCN Circular 36560
Subject
GRB 240529A: AstroSat CZTI detection
Date
2024-05-29T09:32:31Z (a year ago)
From
Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>
Via
Web form
J. Joshi (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:
Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long-duration GRB 240529A which was also detected by Swift-BAT (Eyles-Ferris et al., GCN Circ. 36556).
The source was clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2024-05-29 02:58:30.46 UTC. The measured peak count rate associated with the burst is 372 (+67, -60) counts/s above the background in the combined data of all quadrants, with a total of 6548 (+660, -731) counts. The local mean background count rate was 1334 (+5, -6) counts/s. We measure a T90 of 40 (+-2) s from the cumulative Veto light curve.
The source was also faintly detected in the CZT detectors in the 20-200 keV energy range.
CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.
CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb
GCN Circular 36561
Subject
GRB 240529A: NOT optical observations
Date
2024-05-29T10:55:16Z (a year ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
Via
Web form
S.Y. Fu, J. An, Z.P. Zhu, X. Liu, S.Q. Jiang, D. Xu (NAOC), D. B. Malesani (DAWN/NBI and Radboud), J. Terwel (NOT) report on behalf of a large collaboration:
We observed the field of GRB 240529A detected by Swift (Eyles-Ferris et al., GCN 36556) using the 2.56-m Nordic Optical Telescope (NOT) equipped with the ALFOSC camera, and obtained 3 x 100 s frames in the Sloan r-band and 3 x 100 s frames in z-band, starting at 04:51:50.7 UT on 2024-05-29, i.e., 1.89 hr after the BAT trigger.
The optical afterglow (Eyles-Ferris et al., GCN 36556; Kumar et al. GCN 36559) of the burst is clearly detected in our stacked images. Preliminary photometry results are as follows:
Tmid (UT) Tmid-T0(hr) Mag MagErr Filter
2024-05-29T04:54:47 1.94 16.48 0.05 r
2024-05-29T05:01:30 2.05 15.40 0.05 z
calibrated with nearby PanSTARRS stars.
GCN Circular 36562
Subject
GRB 240529A: Swift/UVOT Detection
Date
2024-05-29T13:07:35Z (a year ago)
From
Sam Shilling at Lancaster University <shilling.sam@gmail.com>
Via
Web form
S.P.R. Shilling (Lancaster U.) and Eyles-Ferris (U. Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 240529A
128 s after the BAT trigger (Eyles-Ferris et al., GCN Circ. 36556).
A source consistent with the enhanced XRT position
(Osborne et al., GCN Circ. 36557) is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 22:21:25.97 = 335.35822 (deg.)
Dec (J2000) = +51:33:43.0 = 51.56194 (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 128 278 147 17.07 +/- 0.04
v 671 691 19 16.16 +/- 0.14
b 598 617 19 17.44 +/- 0.16
u 341 591 246 18.27 +/- 0.10
w1 720 1642 97 >18.8
m2 695 1617 97 >18.7
w2 647 1568 117 >19.1
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.332 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 36563
Subject
GRB240529A: BOOTES-6/DPRT optical detection
Date
2024-05-29T13:24:36Z (a year ago)
From
Youdong HU at INAF-OAB <huyoudong072@hotmail.com>
Via
Web form
I. Perez-Garcia, E. Fernandez-Garcia, M.D. Caballero-Garcia, R. Sanchez-Ramirez, S. Guziy, S.-Y. Wu and A. J. Castro-Tirado (IAA-CSIC, Granada), Y.-D. Hu (INAF-OAB), P. J. Meintjes and H. J. van Heerden (UFS, South Africa), A. Martin-Carrillo and L. Hanlon (UCD, Ireland), C. J. Perez del Pulgar (UMA, Malaga) and D.-R. Xiong (YNAO) on behalf of a larger collaboration, report:
Following the detection of GRB 240529A by Swift (Eyles-Ferris et al. GCNC 36556), the BOOTES-6/DPRT 0.6m robotic telescope at Boyden Observatory in Maselspoort (South Africa) observed the GRB location starting on May. 29, 03:05 UT (~ 7 min after trigger). A series of images in clear filter were gathered and the optical afterglow was detected within the enhanced Swift/XRT position (Osborne et al. GCNC 36557) for which we measure a preliminary magnitude of 15.2 +- 0.1 on the first co-added 10 s x 4 image, which is consistent with the detections of GOTO (Kumar et al. GCNC 36559), NOT (Fu et al. GCNC 36561) and UVOT (Shilling et al. GCNC 36562). Further imaging is ongoing.
We thank the staff at Boyden Observatory for their excellent support.
GCN Circular 36564
Subject
GRB 240529A: Swift-XRT refined Analysis
Date
2024-05-29T14:50:35Z (a year ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
S. Dichiara (PSU), J.A. Kennea (PSU), K.L. Page (U. Leicester), A.P.
Beardmore (U. Leicester), A. Melandri (INAF-OAR), T. Sbarrato
(INAF-OAB), P. D'Avanzo (INAF-OAB), A. Tohuvavohu (U. Toronto) and P.A.
Evans report on behalf of the Swift-XRT team:
We have analysed 5.8 ks of XRT data for GRB 240529A, from 107 s to 19.1
ks after the BAT trigger. The data comprise 344 s in Windowed Timing
(WT) mode (the first 10 s were taken while Swift was slewing) with the
remainder in Photon Counting (PC) mode. A spectrum formed from the WT
mode data can be fitted with an absorbed power-law with a photon
spectral index of 1.945 (+0.015, -0.025). The best-fitting absorption
column is consistent with the Galactic value of 4.1 x 10^21 cm^-2
(Willingale et al. 2013). The PC mode spectrum has a photon index of
2.07 (+0.05, -0.04) and a best-fitting absorption column consistent
with the Galactic value. The counts to observed (unabsorbed) 0.3-10 keV
flux conversion factor deduced from this spectrum is 3.8 x 10^-11 (6.0
x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 4.06 (+0.15, -0.00) x 10^21 cm^-2
Galactic foreground: 4.1 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index: 2.07 (+0.05, -0.04)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01231488.
This circular is an official product of the Swift-XRT team.
GCN Circular 36566
Subject
GRB 240529A: Swift-BAT refined analysis
Date
2024-05-29T17:19:11Z (a year ago)
From
Tyler Parsotan at NASA GSFC <tyler.parsotan@nasa.gov>
Via
email
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),
R. Gupta (GSFC), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa),
M. J. Moss (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 240529A (trigger #1231488)
(Eyles-Ferris et al., GCN 36556). The BAT ground-calculated position is
RA, Dec = 335.341, 51.557 deg which is
RA(J2000) = 22h 21m 22.0s
Dec(J2000) = +51d 33' 25.2"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 26%.
The mask weighted lightcurve shows a complex lightcurve structure with a relatively
gradual rise to the peak at trigger time and multiple pulses present at late times,
at t ~30 and ~50 sec after the trigger time.
T90 (15-350 keV) is 160.67 +- 14.52 sec (estimated error including systematics).
The time-averaged spectrum from -74.8 to 226.4 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.68 +- 0.04. The fluence in the 15-150 keV band is 2.1 +- 0.0 x 10^-05 erg/cm2.
The 1-sec peak photon flux measured from T+0.17 sec in the 15-150 keV band
is 7.7 +- 0.6 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
The results of the batgrbproduct analysis are available at
https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1231488
GCN Circular 36568
Subject
GRB 240529A: Skynet Optical Observations
Date
2024-05-29T18:07:59Z (a year ago)
From
Dylan Dutton at UNC Chapel Hill <ddutton59@gmail.com>
Via
Web form
Dylan Dutton, Daniel Reichart, Joshua Haislip, Vladimir Kouprianov, Megan Dubay, Ruide Fu, Donovan Schlekat, Logan Selph, James Davidson, Edward Murphy, and Carlos Salgado report on behalf of the Skynet Robotic Telescope Network at the University of North Carolina at Chapel Hill.
We observed the field of GRB 240529A with Skynet's 0.6m RRRT telecope located in Virginia. The observation began at 05:19:30 UTC on May, 29 2024 approximately 2.3 hours after the trigger reported by Swift (Eyeles-Ferris et al., GCN 36556) and lasted until 08:33:52 UTC.
We obtained multiple expsoures in the B, V, and R filters. Exposure lengths were calculated using our automated exposure length scaling model.
We clearly detected a bright object within the uncertainty radius of the Swift localization that is consistent with detections from GOTO (Kumar et al. GCN 36559), NOT (Fu et al. GCN 36561), UVOT (Shilling et al. GCN 36562), and BOOTES-6 (Perez-Garcia et al. GCN 36563) at:
R.A. (J2000): 22:21:25.904
Dec. (J2000): 51:33:42.512
We report the photometry below.
ExpLen | Filter | Mag | MagErr | Date | UTC
---------------------------------------------------------
100s | V | 16.557 | 0.116 | May 29, 2023 | 05:19:30
111s | R | 15.838 | 0.032 | May 29, 2023 | 05:21:40
297s | B | 17.587 | 0.032 | May 29, 2024 | 06:11:34
222s | V | 16.537 | 0.015 | May 29, 2024 | 06:16:41
155s | R | 15.669 | 0.011 | May 29, 2024 | 06:20:32
419s | B | 17.635 | 0.029 | May 29, 2024 | 06:23:25
313s | V | 16.618 | 0.014 | May 29, 2024 | 06:30:33
166s | R | 15.839 | 0.012 | May 29, 2024 | 06:35:55
451s | B | 17.883 | 0.034 | May 29, 2024 | 06:38:59
337s | V | 16.764 | 0.015 | May 29, 2024 | 06:46:39
179s | R | 15.916 | 0.012 | May 29, 2024 | 06:52:25
485s | B | 17.833 | 0.031 | May 29, 2024 | 06:55:41
362s | V | 16.960 | 0.017 | May 29, 2024 | 07:03:55
192s | R | 16.212 | 0.015 | May 29, 2024 | 07:10:06
522s | B | 18.377 | 0.048 | May 29, 2024 | 07:13:35
389s | V | 17.119 | 0.018 | May 29, 2024 | 07:22:26
207s | R | 16.297 | 0.015 | May 29, 2024 | 07:29:04
561s | B | 18.320 | 0.043 | May 29, 2024 | 07:32:48
419s | V | 17.090 | 0.017 | May 29, 2024 | 07:42:18
222s | R | 16.315 | 0.014 | May 29, 2024 | 07:49:27
600s | B | 18.366 | 0.042 | May 29, 2024 | 07:53:25
450s | V | 17.192 | 0.017 | May 29, 2024 | 08:03:34
239s | R | 16.372 | 0.014 | May 29, 2024 | 08:11:14
600s | B | 18.440 | 0.046 | May 29, 2024 | 08:15:30
484s | V | 17.417 | 0.021 | May 29, 2024 | 08:25:39
256s | R | 16.624 | 0.018 | May 29, 2024 | 08:33:52
Our images have been calibrated using stars from the APASS catalog.
GCN Circular 36569
Subject
GRB 240529A: J-band detections with WINTER
Date
2024-05-29T19:37:47Z (a year ago)
From
Geoffrey Mo at MIT <gmo@mit.edu>
Via
Web form
Geoffrey Mo (MIT), Viraj Karambelkar (Caltech), Robert Stein (Caltech), Danielle Frostig (MIT), Nathan Lourie (MIT), Tomas Ahumada (Caltech), Benjamin Schneider (MIT), Robert Simcoe (MIT), and Mansi Kasliwal (Caltech) report:
We observed the field of GRB 240529A (Eyles-Ferris et al., GCN 36556; Osborne et al., GCN 36557; Gropp et al., GCN 36558; Joshi et al., GCN 36560; Dichiara et al., GCN 36564; Markwardt et al., GCN 36566) in the near-infrared J-band with the Palomar 1-m telescope, equipped with the 1-square degree WINTER camera (Lourie et al. 2020).
Two epochs of observations were performed. The first epoch began at 2024-05-29T10:18:49 UTC (~7.3 hours after the GRB) and consisted of 29 x 120 s exposures. The second epoch began at 2024-05-29T11:47:42 UTC (~8.8 hours after the GRB) and consisted of 10 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.10888436), with image subtraction performed relative to J-band images from the UKIRT Hemisphere survey (Dye et al., 2017).
We detect the counterpart (Eyles-Ferris et al., GCN 36556; Kumar et al., GCN 36559; Fu et al., GCN 36561; Shilling et al., GCN 36562; Perez-Garcia et al., GCN 36563; Dutton et al., GCN 36568) in both epochs. The (AB) magnitude is J ~ 16.1 mag in the first epoch, and J ~ 16.5 mag in the second epoch.
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 36573
Subject
GRB 240529A: AKO Optical Afterglow Detection
Date
2024-05-30T07:19:31Z (a year ago)
From
Mohammad Odeh at Al Khatim Observatory M44 <mshodeh@gmail.com>
Via
legacy email
Mohammad Odeh (Al-Khatim Observatory, AKO, operated by the International
Astronomical Center in Abu Dhabi, UAE), Nidhal Guessoum, Dalya Akl, Ilmah
Aabdi, and Shaikha AlShamsi (American University of Sharjah, UAE), report:
We observed the field of GRB 240529A (Eyles-Ferris et al., GCN 36556), with
our 0.36m f/7.7 robotic telescope. The observation started on 29 May 2024 at
21:57 (UT) to 30 May 2024 at 00:23 (UT), about 20.2 hours from the trigger.
We obtained multiple 180-sec exposures in Ic and Clear filters. We clearly
detected the optical afterglow at:
R.A. (J2000): 22:21:25.97
Dec. (J2000): +51:33:42.6
Our detection is consistent with the results of (Kumar et al., GCN 36559; Fu
et al., GCN 36561; Shilling et al., GCN 36562; Perez-Garcia et al., GCN
36563; Dutton et al., GCN 36568; Mo et al., GCN 36569).
The following observations were calculated using Atlas catalogue as a
reference:
----------------------------------------------------------------------------
-
ObsTime (mid), Exposure (sec), Filter, Mag
----------------------------------------------------------------------------
-
2024-05-29T23:08:00Z, 24 x 180s (stacked), Ic, 17.9 +/- 0.10
2024-05-29T23:11:00Z, 24 x 180s (stacked), C, Sr = 18.9 +/- 0.07
----------------------------------------------------------------------------
-
The magnitudes are not corrected for galactic extinction.
GCN Circular 36574
Subject
GRB 240529A: Redshift from GTC/OSIRIS+
Date
2024-05-30T11:30:32Z (a year ago)
Edited On
2024-05-30T16:51:04Z (a year ago)
From
Antonio de Ugarte Postigo at OCA <deugarte@oca.eu>
Edited By
Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov> on behalf of Antonio de Ugarte Postigo at OCA <deugarte@oca.eu>
Via
email
A. de Ugarte Postigo (CNRS, OCA/LAM), C. C. Thoene (ASU-CAS), J. F. Agui Fernandez (CAHA), D. B. Malesani (DAWN/NBI and Radboud U.), Rakotondrainibe (LAM), N. R. Tanvir (U. Leicester), J. P. U. Fynbo (DAWN/NBI), L. Izzo (INAF-OACn & DARK/NBI), G. Lombardi (GTC), S. Geier (GTC), A. Cabrera Lavers (GTC), F. Perez-Toledo (GTC), A. Tejero (GTC) report:
We obtained spectroscopy of the afterglow of GRB 240529A (Eyles-Ferris et al. GCN 36556; Kumar et al. GCN 36559; Joshi et al. GCN 36560; Fu et al. GCN 36561; Shilling et al. GCN 36562; Perez-Garcia et al. GCN 36563; Dutton et al. GCN 36568; Mo et al. GCN 36569; Odeh et al. GCN 36573) using OSIRIS+ at the 10.4 m GTC telescope in the Roque de los Muchachos Observatory (La Palma, Spain). The observation consisted of 3x900s exposures using grism R1000B, covering the range between 3600 and 7800 AA at a resolving power of around 600. The observation had a mean epoch 2024-05-30T04:05:55 UT (1.0468 days after the burst onset). At the time of the afterglow acquisition we measure a magnitude of r(AB) = 19.59 +/- 0.05 mag, as compared to PanSTARRS field stars.
In spite of the late observation, the spectrum still shows a bright continuum with many strong spectral features, which we identify as due to at least three absorption systems. The highest redshift one, which we identify as the one corresponding to the redshift of the GRB is at z=2.695. For this system we identify features of HI, SII, SiII SiII*,SiIV, OI, CI, CII, CIV, FeII, AlII and AlIII.
Additionally we detect two strong intervening systems. The highest redshift one has the most prominent features, corresponding to CIV, AlII, AlIII, and FeII at a redshift of z=2.035. The second system, at z=1.695 has features of CIV, AlIII, FeII, MgI, MgII.
GCN Circular 36575
Subject
GRB 240529A: T193/MISTRAL observations
Date
2024-05-30T13:23:17Z (a year ago)
From
Antonio de Ugarte Postigo at OCA <deugarte@oca.eu>
Via
email
C. Adami, S. Basa (LAM/Pytheas/AMU), A. de Ugarte Postigo (CNRS, OCA/LAM), E. Le Floc'h (CEA Paris-Saclay), J. Palmerio (GEPI, Obs. de Paris), F. Schussler (CEA Paris-Saclay) report:
We performed imaging of the field of GRB 240529A (Eyles-Ferris et al. GCN 36556; Kumar et al. GCN 36559; Joshi et al. GCN 36560; Fu et al. GCN 36561; Shilling et al. GCN 36562; Perez-Garcia et al. GCN 36563; Dutton et al. GCN 36568; Mo et al. GCN 36569; Odeh et al. GCN 36573; de Ugarte Postigo et al. GCN 36574) with MISTRAL mounted on the 1.93 m telescope at Observatoire du Haut Provence (OHP, France). The observations consisted of 2 sets of 10x60s exposures in r-band under poor weather conditions, through passing clouds. Using a stack of the 6 only useable frames, we detect the afterglow close to the detection limit. Using as reference field stars from the Pan-STARRS catalogue, we determine a brightness of r(AB) = 19.8 +/- 0.3 mag at a mean date of 2024-05-30T01:52:00 UT, 0.9542 days after the burst. We note that this is slightly fainter but consistent with the value measured by GTC 1.75 hrs later (de Ugarte Postigo et al. GCN 36574).
We acknowledge the excellent support from Observatoire de Haute-Provence and in particular S. Favard for the MISTRAL observations and A. Radcliffe.
GCN Circular 36576
Subject
GRB 240529A: GROWTH-India optical follow-up
Date
2024-05-30T17:30:52Z (a year ago)
From
vishwajeet.s@iitb.ac.in
Via
Web form
T. Mohan, V. Swain, A. Salgundi, R. Kumar, V. Bhalerao (IITB), G.C. Anupama, S. Barway (IIA) and K. Angail (IAO) report on behalf of the GIT team:
We observed the field of GRB 240529A detected by Swift (Eyles-Ferris et al., GCN 36556) with 0.7m GROWTH-India Telescope (GIT). We started the observation at 2024-05-29 19:54:44 UT, i.e., 16.93 hours after the Swift trigger. We obtained multiple exposures of 400 seconds in the r', g' and i' filters. In our stacked images, we clearly detected the afterglow at the coordinates reported by Swift/UVOT Detection (Shilling et al., GCN 36562). The photometry results follow as:
---------------------------------------------------------------------------------
| JD (mid) | t-t0 (days) | Filter | Total Exposure (s) | Magnitude (AB) |
| ----------------- | ----------- |------- | ------------------ | -------------- |
| 2460460.425332341 | 0.801 | g' | 7x400 | 20.43 +/- 0.09 |
| 2460460.349607928 | 0.725 | r' | 8x400 | 19.14 +/- 0.05 |
| 2460460.386415344 | 0.762 | i' | 7x400 | 18.46 +/- 0.08 |
---------------------------------------------------------------------------------
The measurement is calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction.
Based on the publicly avialable photometry (Fu et al., GCN Circ. 36561; Postigo et al., GCN Circ. 36574; Adami et al., GCN Circ. 36575) and our measurements, we find that the source in r'-filter is fading as a power-law with flux proportional to (t−t0)^−alpha where t0 is Swift/BAT triggered time and calculated alpha = 1.12 +/- 0.01.
The GROWTH India Telescope (GIT; Kumar et al. 2022) 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 36577
Subject
GRB 240529A: optical photometry from Konkoly
Date
2024-05-30T20:41:31Z (a year ago)
From
Jozsef Vinko at Konkoly Observator <vinko@konkoly.hu>
Via
legacy email
GRB 240529A: optical photometry from Konkoly
J. Vinko, A. Sodor, R. Konyves-Toth, L. Kriskovics, A. Pal, R. Szakats
(Konkoly Observatory, Hungary)
We report detection and photometry of the optical afterglow of GRB 240529A
(Eyles-Ferris et al. GCN 36556; Osborne et al. GCN 36557; Dichiara et al.
GCN 36564; Markwardt et al. GCN 36566) taken with the RC80 robotic telescope
at Piszkesteto Station of Konkoly Observatory, Hungary. The observations
started on 2024-05-29 22:40:46.49 UT. 5 sets of 300 sec frames were collected
through Sloan g', r'- and i' bands.
The optical afterglow (Kumar et al. GCN 36559; Joshi et al. GCN 36560; Fu et al.
GCN 36561; Shilling et al. GCN 36562; Perez-Garcia et al. GCN 36563;
Dutton et al. GCN 36568; Mo et al. GCN 36569; Odeh et al. GCN 36573;
de Ugarte Postigo et al. GCN 36574; Adami et al. GCN 36575; Mohan et al. GCN 36576)
was detected on the stacked frames with the following magnitudes, calibrated
via nearby PS1 stars:
Date UT-middle t-T0(days) Exp(s) g'(AB) r'(AB) i'(AB)
2024-05-29 23:11:35.78 0.842 5x300 20.28 (0.21) 19.08 (0.09) 18.62 (0.09)
The magnitudes above are not corrected for galactic extinction.
GCN Circular 36578
Subject
GRB 240529A: Insight-HXMT/HE detection
Date
2024-05-31T02:38:28Z (a year ago)
From
tanwj@ihep.ac.cn
Via
Web form
Wenjun Tan, Shaolin Xiong , Xiaobo Li and Chengkui Li
report on behalf of the Insight-HXMT team:
At 2024-05-29T02:58:31.000 (T0), Insight-HXMT/HE detected
GRB 240529A(trigger ID: HEB240529123) in a routine search of the data,
which was also observed by Swift (Eyles-Ferris et al. GCN 36556; C. B. Markwardt et al. GCN 36566).
The Insight-HXMT/HE light curve consists of multiple
pulses with a duration (T90) of 66.23s measured from T0-37.26 s.
The 1s peak rate, measured from T0-0.159 s, is 3138 cnts/sec.
The total counts from this burst is 53027 counts.
URL_LC: https://twikinew.ihep.ac.cn/pubhxmt/HXMT/GRBList/HEB240529123_lc.jpg
All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (deposited energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
the telescope.
Insight-HXMT is the first Chinese space X-ray telescope, which was
funded jointly by the China National Space Administration (CNSA) and
the Chinese Academy of Sciences (CAS).
More information about it could be found at:
http://hxmtweb.ihep.ac.cn/
GCN Circular 36579
Subject
GRB 240529A: MAAO 0.7m telescope optical afterglow detection
Date
2024-05-31T06:20:31Z (a year ago)
From
Gu Lim at Pusan National University <lim9gu@gmail.com>
Via
Web form
Lim, Gu (PNU), Kim, Dohyeong (PNU), Im, Myungshin (SNU), Park, Keun-Hong (MAAO), and Choi, Changmin (MAAO) report on behalf of the GECKO team
We searched for the optical afterglow of GRB 240529A (Eyles-Ferris et al., GCN 36556) with a 0.7m telescope at Miryang Arirang Astronomical Observatory (MAAO; Lim et al. 2024), one of the facilities of the GW EM-Counterpart Korean Observatory (GECKO). We started the observation at 2024-05-29T17:18:13 UT and obtained 10 images of each 120s with I-band 14.3 hours after the Swift detection (GCN 36556). The photometry is performed using 2xFWHM diameter aperture. The flux is calibrated using the APASS DR9 catalog (Henden et al. 2016) by converting the Vega system to the AB system using the Lupton (2005) transformation equation. After the image subtraction using HOTPANTS (Becker et al. 2015), we detected the optical afterglow at:
R.A (J2000): 22:21:25.92
Dec. (J2000): +51:33:43.46
This coordinate is within the uncertainty radius of the enhanced Swift-XRT report (Evans et al., GCN 36557). We determine a magnitude of I=17.46+/-0.19 AB mag without galactic extinction correction. Our detection is agreed with the results of (Odeh et al., GCN 36573).
T0 = 2024-05-29T02:58:31 UT (Eyles-Ferris et al., GCN 36556)
Tmid(UT) Exptime(s) Tmid-T0(hr) FWHM(") Mag+/-Magerr Depth_3sigma Filter
---------------------------------------------------------------------------------------
2024-05-29T17:32:38 180sx10 +14.3 5.6 17.46+/-0.19 18.40 I
Gravitational-wave EM Counterpart Korean Observatory (GECKO; Im et al. 2023, Proceedings of IAU Symp. Vol. 363, pp. 207.; Paek et al. 2024, The Astrophysical Journal, Vol. 960, Number 2, 113.) is a network of 0.5m to 1m class telescopes worldwide.
GCN Circular 36582
Subject
GRB 240529A: SAO RAS optical observations
Date
2024-05-31T19:24:45Z (a year ago)
From
Moskvitin Alexander at SAO RAS <mosk@sao.ru>
Via
legacy email
A. S. Moskvitin, O. I. Spiridonova and V. V. Vlasyuk (SAO RAS),
report on behalf of the GRB follow-up team.
We observed the field of the GRB 240529A (Eyles-Ferris et al.
GCN 36556; Osborne et al. GCN 36557; Joshi et al. GCN 36560;
Dichiara et al. GCN 36564; Markwardt et al. GCN 36566; Tan et al.
GCN 36578