GRB 231111A
GCN Circular 35189
Subject
GRB 231111A: Optical follow-up observations at Terskol, AbAO, Maidanak, Mondy, Assy
Date
2023-11-26T08:22:44Z (2 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
Via
legacy email
N. Pankov (HSE, IKI), A. Pozanenko (IKI), I. Sokolov (INASAN), R. Inasaridze (AbAO), O. Burhonov (UBAI), E. Klunko (ISTP), V. Kim (FAI), Sh. Ehgamberdiev (UBAI), S. Belkin (IKI) report on behalf of GRB-IKI-FuN collaboration:
We observed the field of GRB 231111A (Melandri et al., GCN 34981; Zhang et al, GCN 34990) at with several telescopes, Zeiss-2000 telesope (Terskol), AS-32 (Abastumani), AZT-22 (Maidanak), AZT-33IK (Mondy) and AZT-20 (Assy).The observations started at Terskol on 2023-11-11 17:37:54, i.e. 3.359712 hr since Swift trigger. The optical source is detected only in the stacked image of 12*300 sec from Maidanak Observatory in the R-filter, while in other cases we obtained the upper limits. The results are in consistent with observations previously reported by other teams and us (Melandri et al., GCN 34981; Jiang et al, GCN 34982; Lipunov et al, GCN 34983; Kumar et al, GCN 34984; Sun et al, GCN 34985; Pankov et al, GCN 34994; Ruocco et al, GCN 34997; Wang et al, GCN 35000; Li et al, GCN 35001; Sun et al, GCN 35002; Moretti et al, GCN 35003; Komesh et al, GCN 35004; D'Avanzo et al, GCN 35007; Thoene et al, GCN 35009; Jiang et al, GCN 35012; Sun et al, GCN 35014). Preliminary photome!
try is following:
Date UT start t-T0 Exp. Filter OT Err. UL(3sigma) Telescope
2023-11-11 17:37:54 0.13998 2*120 R n/d n/d 19.5 Zeiss-2000
2023-11-12 14:47:53 1.02157 86*60 R n/d n/d 20.5 AS-32
2023-11-12 19:25:37 1.21583 12*300 R 21.06 0.08 22.7 AZT-22
2023-11-13 11:14:51 1.87399 50*120 R n/d n/d 20.7 AZT-33IK
2023-11-13 15:09:27 2.07092 200*30 r n/d n/d 23.0 AZT-20
The photometry is based on nearby stars from USNO-B1.0 and PS1 catalogs.
GCN Circular 35069
Subject
GRB 231111A: Swift/UVOT Detection
Date
2023-11-17T00:10:52Z (2 years ago)
From
Sam LaPorte at PSU <sjl5346@psu.edu>
Via
email
GRB 231111A: Swift/UVOT Detection
S. J. LaPorte (PSU) and A. Melandri (INAF-OAR)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 231111A
165 s after the BAT trigger (Melandri et al., GCN Circ. 34981).
A source consistent with the XRT position
(Evans et al., GCN Circ. 34991)
is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 19:20:45.25 = 290.18856 (deg.)
Dec (J2000) = +52:26:10.5 = 52.43624 (deg.)
with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence).
Preliminary detections 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
b 26598 27505 885 >20.41
uvm2 34150 34575 418 >20.05
u 180 418 234 16.52
v 33541 34144 590 >19.85
uvw1 38947 39736 776 >20.24
uvw2 27512 85141 1176 >20.65
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.117 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 35033
Subject
GRB 231111A: Swift-BAT refined analysis
Date
2023-11-15T00:21:53Z (2 years ago)
From
Mike Moss at NASA GSFC <mikejmoss3@gmail.com>
Via
Web form
A. Y. Lien (U Tampa), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
C. B. Markwardt (GSFC), A. Melandri (INAF-OAR),
M. J. Moss (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+200 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 231111A (trigger #1195887)
(Melandri, et al., GCN Circ. 34981). The BAT ground-calculated position is
RA, Dec = 290.197, 52.440 deg which is
RA(J2000) = 19h 20m 47.3s
Dec(J2000) = +52d 26' 22.9"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 61%.
The BAT light curve shows a FRED-pulse structure peaking ~0 seconds after the trigger time.
T90 (15-350 keV) is 34.08 +- 4.88 sec (estimated error including systematics).
The time-averaged spectrum from T-5.32 to T+40.06 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.58 +- 0.07. The fluence in the 15-150 keV band is 3.4 +- 0.1 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T+0.07 sec in the 15-150 keV band
is 2.7 +- 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/1195887/BA/
GCN Circular 35014
Subject
GRB231111A: MDM 2.4m Hiltner Telescope Observation
Date
2023-11-13T16:57:13Z (2 years ago)
From
Tianrui Sun at Purple Mountain Obs,CAS <trsun@pmo.ac.cn>
Via
legacy email
Tian-Rui Sun, Tian-Ci Zheng, Hui-Yang Mao, Jiang-Tao Li report:
Following the detection of GRB 231111A by SWIFT (Melandri et al., GCN 34981; Osborne et al., GCN 34991;GCN 34995), MASTER (Lipunov et al., GCN 34980; GCN 34983), Nanshan/HMT (Jiang et al., GCN 34982), GIT (Kumar et al., GCN 34984), YAHPT (Sun et al., GCN 34985), GECAM (Zhang et al., GCN 34990; GCN 34993), Mondy (Pankov et al., GCN 34994), Terskol Zeiss-2000 (Pankov et al., GCN 34996), Nastro Verde (Dainotti et al., GCN 34997), GMG (Mao et al., GCN 34999; GCN 35001), Mephisto (Sun et al., GCN 35002), Leavitt (Moretti et al., GCN 35003), NUTTelA-TAO (Komesh et al., GCN 35004) and Xinglong-2.16m (Jiang et al., GCN 35012), we conducted observations using the MDM 2.4m Hiltner telescope with the clear filter.
This observation began from 2023-11-12T01:44:16.415, about 11.4 hours after the burst.
The PSF photometry results are shown as :
----------------------------------------------------
UT exposure filter mag magerr
------------------------------------------------------
2023-11-12T01:44:16.415 600 Clear 20.7669 +/- 0.0622
2023-11-13T01:35:18.404 600 Clear 22.1815 +/- 0.0697
------------------------------------------------------
We used the GAIA-DR3 catalogue (G mag) as the magnitude reference for calibration.
GCN Circular 35012
Subject
GRB 231111A: Xinglong-2.16m optical observations
Date
2023-11-13T15:33:47Z (2 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
Via
email
S.Q. Jiang, Z.P. Zhu, S.Y. Fu, J. An, X. Liu, T.H. Lu, D. Xu (NAOC) report:
We observed the optical afterglow of GRB 231111A detected by Swift (Melandri et al., GCN 34981) using the 2.16m telescope
located at Xinglong, Hebei, China, equipped with the BFOSC camera. Observations started at 14:34:11 UT on 2023-11-11 (i.e., 16.87 min after the Swift/BAT trigger), and 3x200, 9x300 s frames were obtained in the R-band.
Preliminary photometric results of the optical afterglow (e.g., Melandri et al. GCN 34981; Jiang et al. GCN 34982; Lipunov et al. GCN 34983; Kumar et al. GCN 34984; Sun et al. GCN 34985; Pankov et al. GCN 34994; Ruocco et al. GCN 34997; Li et al. GCN 35001; Sun et al. GCN 35002; Moretti et al. GCN 35003; Komesh et al. GCN 35004) are as follows:
Tmid-T0 (day) Filter Magnitude (5-sigma)
0.0153 R 17.89 +/- 0.01
0.8523 R >21.6
calibrated with the nearby Pan-STARRS field.
We thank the great support of the Xinglong-2.16m staff.
GCN Circular 35009
Subject
GRB 231111A: Afterglow redshift from OSIRIS+/GTC
Date
2023-11-13T11:53:53Z (2 years ago)
From
C. C. Thoene at ASU-CAS <christina.thoene@gmail.com>
Via
Web form
C. C. Thoene (ASU-CAS), A. de Ugarte Postigo (CNRS/OCA), L. Izzo (INAF/Capodimonte), F. Agui Fernandez (CAHA), F. Perez Toledo (GTC), M. Blazek (CAHA), J. Fynbo (DAWN/NBI), S. Geier (GTC) and N.R. Tanvir (Univ. Leicester) report:
We observed the afterglow of GRB 231111A (Melandri et al. GCN 34981, Jiang et al. GCN 34982) with OSIRIS+ at the 10.4m GTC on Nov. 11, 2023, starting at 20:19:13 UT, 6h after the GRB. We obtained 3x900s exposures under bad seeing conditions (1.9 arcsec) using the R1000B grism, which gives a wavelength coverage between 3700 and 7800 A. At the time of observations, the afterglow had a magnitude of r~20.2 as determined from the acquisition image.
In the combined spectrum we detect the MgII 2796,2803 Å doublet and faint lines of FeII 2585 and 2600 Å, which results in a redshift of z=1.179. TNG (D’Avanzo et al. GCN 35007) also claims the detection of a MgII doublet, however, at their reported redshift of z=1.39, no lines are present in our spectrum. No fine-structure lines are detected, making the redshift of 1.179 strictly seen as a lower limit. However, given the lack of further emission or absorption features in the spectral range and the upper limit of z~2 due to the detection of continuum down to 3650 Å (similar to the claim of D'Avanzo et al. GCN 35007) we expect this to be the actual redshift of the GRB.
We acknowledge the excellent support by the GTC staff.
GCN Circular 35007
Subject
GRB 231111A: TNG tentative redshift
Date
2023-11-13T10:40:29Z (2 years ago)
From
Paolo D'Avanzo at INAF-OAB <pda.davanzo@gmail.com>
Via
legacy email
P. D'Avanzo (INAF-OAB), V. D'Elia (ASI/SSDC & INAF/OAR), D. B. Malesani (DAWN/NBI & Radboud Univ.), A. Melandri (INAF/OAR) , M. Cecconi, C. P. Padilla-Torres (INAF/TNG) report on behalf of the CIBO collaboration:
We report observations of GRB 231111A (Melandri et al. GCN Circ. 34981) with the 3.6m Telescopio Nazionale Galileo (TNG) equipped with DOLORES.
We acquired a spectrum of the optical source reported by Melandri et al. (GCN Circ. 34981). We obtained 2x1200 s with the LR-B grism, for a total exposure of 2400 s, covering the wavelength range 3500 - 8000 AA. The observations started on 2023-11-11 at 19:31:33 UT (i.e. about 5.2 hours after the GRB detection).
The reduced spectrum is rather noisy and extends down to at least 3600 AA, indicating that the redshift is likely lower than z ~ 2. From preliminary reduction and calibration we tentatively infer a redshift of z ~ 1.39 from the possible detection of MgII 2796,2803.
Further analysis is ongoing.
GCN Circular 35004
Subject
GRB 231111A NUTTelA-TAO / BSTI Early Measurements
Date
2023-11-12T18:00:28Z (2 years ago)
From
Toktarkhan Komesh at Nazarbayev University <toktarkhan.komesh@nu.edu.kz>
Via
Web form
T. Komesh (NU), B. Grossan (UCB, NU), Zh. Maksut (NU), Zh. Abdullayev (NU), M. Krugov (FAI), and E. Abdikamalov (NU) report on behalf of the Energetic Cosmos Laboratory:
The Nazarbayev University Transient Telescope at Assy-Turgen Astrophysical Observatory (NUTTelA-TAO) pointed at GRB231111A on receipt of an automated GCN / BAT position alert, observing in Sloan g', r' and i' bands, with the Burst Simultaneous Three-Channel Imager (BSTI; Grossan, Kumar & Smoot 2019, JHEA, 32, 14).
We started observations at UT 2023-11-11 14:18:02, 43 s after the BAT trigger. Observations were made under partially cloudy conditions. A new and changing source consistent with the XRT position (Osborne 2023, GCN 34991) was detected. Note that these observations provide essentially full-time coverage, simultaneous in all three bands. We report the following photometric values for the OT:
tc-t0(s) g'(mag) r'(mag) i'(mag) exposure_time (s)
---- ----- ----- ----- -----
69 16.6 16.3 16.0 52.5
133 16.8 16.3 16.4 75
208 17.1 16.7 16.7 75
283 17.2 16.8 16.8 75
358 17.3 16.9 16.8 75
433 17.5 17.2 17.0 75
508 17.6 17.3 17.2 75
583 17.6 17.4 17.3 75
658 17.7 17.5 17.3 75
733 18.0 17.7 17.3 75
808 17.9 17.7 17.6 75
883 18.1 17.9 17.6 75
958 18.0 17.8 17.7 75
1033 18.0 17.9 17.6 75
1108 18.2 18.0 17.6 75
1183 18.0 18.2 17.9 75
1296 18.4 18.3 18.0 150
1446 18.4 18.2 17.9 150
Uncertainties are estimated at ~ 0.1 mag for all three filters. tc-t0 = trigger time minus image center time. Calibration was done with 5 bright Pan-STARRS catalog stars on our images, and no other analysis or corrections.
We caution the reader that these are preliminary results, without color or other corrections, and will likely change in small measure. Please also note that times are approximate.
----------------------------------
NU = Nazarbayev University, Nur-Sultan, Kazakhstan
UCB = University of California, Berkeley, USA
FAI = Fesenkov Astrophysical Institute, Kazakhstan
This research has been funded by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan (Grant No. AP14870504). The NUTTelA-TAO Team acknowledges the support of the staff of the Assy-Turgen Astrophysical Observatory, Almaty, Kazakhstan, and the Fesenkov Astrophysical Institute, Almaty, Kazkhstan.
GCN Circular 35003
Subject
GRB 231111A: Leavitt Observatory optical observations
Date
2023-11-12T17:16:00Z (2 years ago)
From
leavittob@gmail.com
Via
Web form
L. Moretti and E. Pavoni (Leavitt Observatory), in a large collaboration with:
M.G. Dainotti (National Astronomical Observatory of Japan),
Y. Niino (Tokyo University, Institute of Astronomy),
K. Kalinowski (Aarhus University, Department of Physics and Astronomy),
B. De Simone (Universita' degli Studi Di Salerno)
report:
We imaged the field of GRB 231111A (Lipunov et al., GCN 34980; Melandri et al., GCN 34981; Jiang et al., GCN 34982; Lipunov et al., GCN 34983; Kumar et al., GCN 34984; Osborne et al., GCN 34991; Wen-Long Zhang et al., GCN 34993; Pankov et al., GCN 34994; Osborne et al., GCN 34995; Ruocco, GCN 34997; Li et al., GCN 35001) with the telescope of Leavitt Observatory, Italy. Member of:
UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili, GRB section.
ATA - Associazione Tuscolana di Astronomia.
The observations started 189 minutes after the BAT trigger, at 17:26:49 UT on 2023/11/11, with our RC telescope D=250 mm F/D=8.
Weather conditions were medium, with light and variable cloud cover.
We co-added 15 images of 120 sec each, acquired from 17:26:49 to 18:20:58 UT. All images are R (Cousins) filtered, calibrated with master dark and master flat.
We confirm a fading afterglow in the error box of the astrometrically corrected position measured by Swift-XRT (GCN 34991), at the following coordinates +/- 2 arcsec:
RA(J2000.0) = 19h 20m 45.25s
DEC(J2000.0) = +52d 26' 09.9''
The result of our photometry is:
-------------------------------------------------------------------------
JD_UTC at mid-exposure mag Err Flt
-------------------------------------------------------------------------
2460260.2464583 20.1 +/- 0.2 R
Magnitudes were estimated with the Gaia DR3 catalogue (*) and are not corrected for galactic dust extinction.
The message may be cited.
(*) https://gea.esac.esa.int/archive/documentation/GEDR3/Data_processing/chap_cu5pho/cu5pho_sec_photSystem/cu5pho_ssec_photRelations.html
GCN Circular 35002
Subject
GRB231111A: Optical follow-up observations with Mephisto
Date
2023-11-12T15:11:08Z (2 years ago)
From
Tianrui Sun at Purple Mountain Obs,CAS <trsun@pmo.ac.cn>
Via
legacy email
Tian-Rui Sun, Xin-Lei Chen, Xiangkun Liu, Yuan-Pei Yang, Tianyu Zhang, Helong Guo, Guowang Du, Haipeng Lei, Brajesh Kumar, Xiaowei Liu report on behalf of the Mephisto Collaboration:
Following the detection of GRB 231111A by SWIFT (Melandri et al., GCN 34981, Osborne et al., GCN 34991 and GCN 34995), MASTER (Lipunov et al., GCN 34980, GCN 34983) , Nanshan/HMT (Jiang et al., GCN 34982), Git (Kumar et al., GCN 34984), YAHPT (Sun et al., GCN 34985), Gecam (Zhang et al, GCN 34990 and 34993), Mondy (Pankov et al., GCN 34994), Terskol Zeiss-2000 (Pankov et al., GCN 34996), Nastro Verde (Dainotti et al., GCN 34997), GMG (Mao et al., GCN 34999, GCN 35001), we conducted observations using the Multi-channel Photometric Survey Telescope (Mephisto) of Yunnan University at Lijiang Observatory (IAU code: 044) of Yunnan Astronomical Observatories, Chinese Academy of Sciences (CAS) to search and follow up its afterglow near SWIFT/UVOT position.
We simultaneously observed the target position with 60s exposure in u/g bands and v/r bands starting from 11 Nov 2023, UTC 14:49:05, about 1905 seconds after the burst.
At the beginning of our observation:
Filter |Mag |Magerr | Time |reference
Mu |19.48| 0.12 | 2023-11-11T14:56:35 |Mephisto u
Mv |19.13| 0.07 | 2023-11-11T14:49:05 |Mephisto v
Mg |18.65| 0.04 | 2023-11-11T14:56:35 |Mephisto g
Mr |18.15| 0.04 | 2023-11-11T14:49:05 |Mephisto r
To do the flux calibration, we chose the exposure with the best image quality as the reference image, and used stars of signal-to-noise ratio (SNR) >30 after removing variables by cross-matching with variable catalogs in each band to scale the flux level to that of the reference image. Atmospheric extinction corrections and instrumental magnitude zero points are applied to the reference image.
Mephisto is a 1.6-m 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 will yield real-time, high-quality colors of unprecedented accuracy of billions of objects, enable fast and robust classification of variables and transients, and for the first time, deliver a panoramic and panchromatic documentary of our dynamic universe. The on-site telescope assemblage and commissioning were carried out in September 2022, and the first light with the small system of 4 filters (uviz) in dual channels was achieved on October 23, 2022. Mephisto is currently equipped with two commercial Andor iKon-XXL single-chip CCD cameras for the blue and yellow channels. Each camera covers an area about a quarter of the full field-of-view (2°in diameter).
[Editor's Note: The subject was modified at the user's request to list the correct GRB name.]
GCN Circular 35001
Subject
GRB 231111A: GMG observation (correction)
Date
2023-11-12T14:40:17Z (2 years ago)
From
Rui-Zhi Li at Yunnan Astronomical Observatory, CAS <liruizhi@ynao.ac.cn>
Via
Web form
R.-Z. Li, B.-T. Wang, J. Mao, X. Ding, J.-M. Bai (YNAO) report:
We observed the field of GRB 231111A (Melandri et al. GCN 34981) by the GMG telescope in Yunnan observatories. The observation began from UT 11:29:03 Nov 12, 2023, about 21.2 hours from the trigger. The preliminary results are shown as
----------------------------------------------------
UT filter mag
----------------------------------------------------
2023-11-12T11:29:03.291 R 22.2 ± 0.4
----------------------------------------------------
We apologize for any inconvenience this may have caused.
GCN Circular 34999
Subject
GRB 231111A: GMG observation upper limit
Date
2023-11-12T12:30:52Z (2 years ago)
From
Jirong Mao at Yunnan Obs <jirongmao@mail.ynao.ac.cn>
Via
Web form
B.-T. Wang, R.-Z. Li, J. Mao, X. Ding, J.-M. Bai report:
We observed the field of GRB 231111A ( Melandri et al. GCN 34981) by the GMG telescope in Yunnan observatories. The observation began from UT 11:29:03 Nov 12, 2023, about 21.2 hours from the trigger. We could not observe the optical afterglow down to a magnitude limit of R~20.7.
GCN Circular 34997
Subject
GRB 231111A: Osservatorio Astronomico "Nastro Verde" optical observations with detection of an optical counterpart
Date
2023-11-12T11:03:17Z (2 years ago)
From
Nello Ruocco at Osservatorio Nastro Verde - Sorrento (Naples) - Italy - MPC Code C82 <osservatorionastroverde@gmail.com>
Via
Web form
Nello Ruocco at Osservatorio Nastro Verde - Sorrento (Naples) - Italy
in a large collaboration with:
M.G. Dainotti (National Astronomical Observatory of Japan),
Y. Niino (Tokyo University, Institute of Astronomy),
K. Kalinowski (Aarhus University, Department of Physics and Astronomy),
B. De Simone (Universita' degli Studi Di Salerno)
report:
Following the Swift trigger no. 1195887 (GCN 34981 A. Melandri et al) from the Swift Burst Alert Telescope (BAT), we pointed at the coordinates RA(J2000)=19h 20m 45.96s: Dec(J2000)=52d 26' 17.9" and started our observations with telescope of Nastro Verde Observatory - Sorrento (Naples), Italy.
Member of:
AAVSO - American Association of Variable Star Observers.
UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili.
AstroCampania Associazione.
The observations started at 18:00 UT of 2023/11/11, after about 4 hours after the GRB trigger, with light cloud veils that left large spaces of clear sky, with principal telescope SC 0.35 f/10 with focal reduced + CCD Sbig ST10 XME
I took 13 unfiltered images of 120 sec and 26 unfiltered images of 60 sec . All images, calibrated with masterdark and masterflat have been measured with Thycho Tracker and Astrometrica software
We have detected a faint source at the enhanced position reported by Swift-XRT team (J.P. Osborne et al., GCN 34991 )
at following position
RA (J2000.0) 19 20 45.12
Dec (J2000.0) +52 26 10.2
with the following photometry and astrometry:
GRB 23111 KC2023 11 11.82061 19 20 45.12 +52 26 10.2 20.4 C82
Magnitudes were estimated with the GAIA DR2 cat. and are not corrected for galactic dust extinction.
Further observations are encouraged.
The message may be cited.
GCN Circular 34995
Subject
GRB 231111A: Swift-XRT refined Analysis
Date
2023-11-12T04:47:24Z (2 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
J.P. Osborne (U. Leicester), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti
(INAF-OAB), A. D'Ai (INAF-IASFPA), D.N. Burrows (PSU), J. D. Gropp
(PSU), S. Dichiara (PSU), K.L. Page (U. Leicester) and P.A. Evans
report on behalf of the Swift-XRT team:
We have analysed 7.3 ks of XRT data for GRB 231111A, from 93 s to 39.7
ks after the BAT trigger. The data comprise 296 s in Windowed Timing
(WT) mode (the first 5 s were taken while Swift was slewing) with the
remainder in Photon Counting (PC) mode.
The late-time light curve (from T0+16.2 ks) can be modelled with a
power-law decay with a decay index of alpha=1.03 (+/-0.23).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.47 (+0.10, -0.06). The
best-fitting absorption column is 1.297 (+0.206, -0.027) x 10^21
cm^-2, consistent with the Galactic value of 1.3 x 10^21 cm^-2
(Willingale et al. 2013). The PC mode spectrum has a photon index of
1.98 (+0.19, -0.18) and a best-fitting absorption column of 1.6 (+0.6,
-0.3) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV
flux conversion factor deduced from this spectrum is 3.5 x 10^-11 (4.6
x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.6 (+0.6, -0.3) x 10^21 cm^-2
Galactic foreground: 1.3 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.98 (+0.19, -0.18)
If the light curve continues to decay with a power-law decay index of
1.03, the count rate at T+24 hours will be 0.029 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 10.0 x
10^-13 (1.3 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01195887.
This circular is an official product of the Swift-XRT team.
GCN Circular 34994
Subject
GRB 231111A: Mondy optical observations
Date
2023-11-12T03:05:47Z (2 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
Via
legacy email
N. Pankov (HSE, IKI), E. Klunko (ISTP), A. Pozanenko (IKI), S. Belkin (IKI,HSE) report on behalf of GRB IKI FuN:
We observed the field of Swift GRB 231111A (Melandri et al. GCN 34981) with AZT-33IK telescope of Mondy observatory in R-filter on
2023-11-11 starting (UT) 14:36:53. We detect afterglow (Melandri et al. GCN 34981; Jiang et al. GCN 34982; Lipunov et al. GCN 34983) within Enhanced Swift-XRT error circle.
Preliminary photometry of first images is following
Date UT start t-T0 Exp. Filter OT Err. UL(3sigma)
(mid, days) (s)
2023-11-11 14:36:53 0.014284 1x120 R 18.24 0.08 20.3
The photometry is based on nearby USNO-B1.0 R2 stars.
GCN Circular 34993
Subject
GRB 231111A: GECAM-C detection of a long burst (correction)
Date
2023-11-12T02:28:22Z (2 years ago)
From
wenlongzhang2018@163.com
Via
Web form
Wen-Long Zhang, Shao-Lin Xiong, Yue Huang report on behalf of the GECAM team:
GECAM-C was triggered by a long burst, GRB 231111A, at 2023-11-11T14:17:19.850 UTC (T0), which was also observed by Swift/BAT (GCN #34981) .
According to the realtime alert data, the GECAM-C light curve shows roughly two peaks with a total duration of ~30 sec (20-1000 keV).
The time-averaged spectrum of GECAM-C realtime data from about T0 to T0+20 s could be adequately fit by a cut-off power-law with a flux about 3.3E-7 erg/cm^2/s in 20-1000 keV.
We note that these results are based on realtime alert data and thus very preliminary. Refined analysis will be reported later.
Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM) mission originally consists of two microsatellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS).
GCN Circular 34991
Subject
GRB 231111A: Enhanced Swift-XRT position
Date
2023-11-12T01:50:29Z (2 years 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 2772 s of XRT Photon Counting mode data and 5 UVOT
images for GRB 231111A, 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 = 290.18884, +52.43571 which is equivalent
to:
RA (J2000): 19h 20m 45.32s
Dec (J2000): +52d 26' 08.6"
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 34990
Subject
GRB 231111A: GECAM-C detection of a long burst
Date
2023-11-12T01:02:21Z (2 years ago)
From
wenlongzhang2018@163.com
Via
Web form
Wen-long Zhang, Shaoli Xiong, Yue Huang report on behalf of the GECAM team:
GECAM-C was triggered by a long burst, GRB 231111A, at 2023-11-11T14:17:19.850 UTC (T0), which was also observed by Swift/BAT ( GCN 34981) .
According to the realtime alert data, the GECAM-C light curve shows roughly two peaks with a total duration of ~30 sec (20-1000 keV).
The time-averaged spectrum could be adequately fit by a Band function with a flux about 3.36E-7 erg/cm2 in 20-1000 keV.
We note that these results are based on realtime alert data and thus very preliminary. Refined analysis will be reported later.
Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM) mission originally consists of two microsatellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS).
GCN Circular 34985
Subject
GRB231111A: YAHPT Observations
Date
2023-11-11T18:04:47Z (2 years ago)
From
Tianrui Sun at Purple Mountain Obs,CAS <trsun@pmo.ac.cn>
Via
legacy email
Tian-Rui Sun, Jin-Jun Geng, Jian Chen and Lei Hu report on behalf of the YAHPT team:
Following the detection of GRB 231111A by SWIFT (Melandri et al., GCN 34981), MASTER (Lipunov et al., GCN 34980, GCN 34983) and Nanshan/HMT (Jiang et al. GCN 34982), we conducted observations using the Yaoan High Precision Telescope at Yaoan Astronomy Observation Station (YAHPT; Yunnan province, China) to search and follow up its afterglow around the SWIFT/UVOT detection.
Our follow-up imaging obervations adopted 180s exposure in Rc-band starting from 11 Nov 2023, UTC 14:47:12.70, about 1792.99 seconds after the burst.
The YAHPT observations detected a declining optical afterglow from 18.34 +/- 0.07 mag to 18.98 +/- 0.12 mag in Rc band throughout our observations.
We monitored this object until it is technically unobservable for our telescope, at about 4755 second after the burst.
We used the USNO B1.0 catalog (R1mag) as the magnitude reference for calibration.
[Editor's Note: The subject was modified at the user's request to list the correct GRB name.]
GCN Circular 34984
Subject
GRB231111A: GIT confirmation of the optical afterglow
Date
2023-11-11T17:31:04Z (2 years ago)
From
Anirudh Salgundi <salgundi.anirudh@gmail.com>
Via
Web form
R. Kumar, A. Salgundi, V. Swain, V. Bhalerao (IIT Bombay), S. Barway, G. C. Anupama (IIA), K. Angail (IAO)
We observed the field of GRB 231111A detected by Swift (Melandri et al., GCN 34981) with 0.7m GROWTH-India Telescope (GIT). We started the observation at 14:30:41 UT on 2023-11-11, i.e., 14.46 minutes after the Swift trigger. We obtained multiple frames in the g' and r' bands, and have a clear detection at the position reported by Swift/XRT (Melandri et al., GCN 34981). The details of the photometry are given in the below table:
----------------------------------------------------------------------
JD (mid) | t-t0 (minutes) | Filter | Exposure (s) | Magnitude (AB) |
----------------------------------------------------------------------
2460260.105395619 | 14.46 | r' | 200 | 17.88 +/- 0.05 |
2460260.108019142 | 18.23 | g' | 200 | 18.35 +/- 0.04 |
2460260.110584214 | 21.92 | r' | 200 | 18.24 +/- 0.04 |
2460260.113222184 | 25.72 | g' | 200 | 18.64 +/- 0.04 |
2460260.204636255 | 157.36 | r' | 300 | 19.52 +/- 0.07 |
2460260.208421405 | 162.81 | g' | 300 | 19.99 +/- 0.07 |
----------------------------------------------------------------------
Based on our photometry, we find that the source is consistently fading with power-law decay rate of 0.69 +/- 0.04 in both g' and r' band. Our results are consistent with magnitudes and decay rate obtained by Nanshan/HMT (Jiang et al. GCN 34982). 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) 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 34983
Subject
GRB 231111A: MASTER OT earlier detection
Date
2023-11-11T16:40:06Z (2 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
legacy email
V. Lipunov, P.Balanutsa (Lomonosov MSU), N.Budnev, O.Gress (ISU, API),A.Sankovich,
D.Vlasenko, Yu.Tselik, Ya.Kechin, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, N.Tiurina,
A.Chasovnikov, I.Gorbunov, D.Zimnukhov, V.Senik, V.Topolev, D.Cheryasov, A.Sosnovskij, V.Senik (Lomonosov Moscow State University, SAI, Physics Department),
R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias),
D. Buckley (South African Astronomical Observatory),
R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico FelixAguilar OAFA),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov (Blagoveschensk Educational State University)
MASTER Global robotic net (http://observ.pereplet.ru Lipunov et al.,2010,Advances in Astronomy,2010,30L)
started (Lipunov et al. GCN 34980)
Swift GRB 231111A (Ttrigger=14:17:19UT, Melandri al. GCN 34981, XRTstart=99s after trigger time)
17s after notice time at 14:17:57UT.
We detected optical counterpart (Melandri et al. GCN 34981) of GRB 231111A
MASTER OT J192045.23+522610.1 from first image at rise stage.
We see Smooth Optical Self-similar Emission of this Gamma-Ray Bursts
(SOSS-emission, Lipunov et al. 2017, ApJ, 845, id9 https://ui.adsabs.harvard.edu/abs/2017ApJ...845...52L/abstract )
Observations and reduction will be continued.
GCN Circular 34982
Subject
GRB 231111A: Nanshan/HMT optical observations
Date
2023-11-11T16:34:46Z (2 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
Via
email
S.Q. Jiang, Z.P. Zhu, S.Y. Fu, J. An, X. Liu, T.H. Lu, D. Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report:
We observed the optical afterglow of GRB 231111A detected by Swift (Melandri et al., GCN 34981) using the HMT-0.5m telescope located at Nanshan, Xinjiang, China. Observations started at 14:18:35 UT on 2023-11-11, i.e., 75 s after the Swift/BAT trigger, and we obtained a serise of 3x20, 3x40, 4x60, 4x90, 4x120, 4x200 s frames without any filter.
The optical afterglow has been decaying during our observations from m(r)~16.04 mag @85 s post-burst to m(r)~18.77 mag @2734 s post-burst, roughly in a powerlaw with a decay index of ~ -0.7, calibrated with the nearby PanSTAR field in the Sloan r-filter and the magnitude is not corrected for Galactic extinction.
GCN Circular 34981
Subject
GRB 231111A: Swift detection of a burst with an optical counterpart
Date
2023-11-11T14:33:33Z (2 years ago)
From
Jamie Kennea at Penn State <jak51@psu.edu>
Via
email
A. Melandri (INAF-OAR), E. Ambrosi (INAF-IASFPA),
A. D'Ai (INAF-IASFPA), S. Dichiara (PSU), J.D. Gropp (PSU),
J. A. Kennea (PSU) and D. M. Palmer (LANL) report on behalf of the
Neil Gehrels Swift Observatory Team:
At 14:17:19 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 231111A (trigger=1195887). Swift slewed immediately to
the event. The BAT on-board calculated location is
RA, Dec 290.234, +52.447 which is
RA(J2000) = 19h 20m 56s
Dec(J2000) = +52d 26' 49"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). Due to a telemetry outage, there is no
immediately available BAT lightcurve information. However the
trigger information indicates an initial count rate of
3100 counts/s (25-100 keV) on a 1 second timescale.
The XRT began observing the field at 14:18:59.3 UT, 99.6 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 290.1915, 52.4383 which is equivalent to:
RA(J2000) = 19h 20m 45.96s
Dec(J2000) = +52d 26' 17.9"
with an uncertainty of 5.5 arcseconds (radius, 90% containment). This
location is 98 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy.
UVOT took a finding chart exposure of 238 seconds with the U filter starting
164 seconds after the BAT trigger. There is a candidate afterglow in the
rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 19:20:45.24 = 290.18848
DEC(J2000) = +52:26:10.5 = 52.43626
with a 90%-confidence error radius of about 0.62 arc sec. This position is 9.9
arc sec. from the center of the XRT error circle. The estimated magnitude is
16.51 with a 1-sigma error of about 0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.117.
Burst Advocate for this burst is A. Melandri (andrea.melandri 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/)