GRB 230622A
GCN Circular 34058
Subject
GRB 230622A: Swift detection of a burst
Date
2023-06-22T10:25:32Z (2 years ago)
From
K.L. Page at U Leicester <klp5@leicester.ac.uk>
A. Melandri (INAF-OAR), A. D'Ai (INAF-IASFPA), J. A. Kennea (PSU),
K. L. Page (U Leicester) and M. H. Siegel (PSU) report on behalf of
the Neil Gehrels Swift Observatory Team:
At 10:04:21 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 230622A (trigger=1176135). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 292.532, -32.922 which is
RA(J2000) = 19h 30m 08s
Dec(J2000) = -32d 55' 16"
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 5 sec. The peak count rate
was ~2020 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 10:10:36.3 UT, 375.1 seconds after
the BAT trigger. No source was detected in the 2.5-s promptly available
image. We are waiting for the full dataset to detect and localise the
XRT counterpart.
UVOT took a finding chart exposure of 114 seconds with the White filter
starting 378 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of
the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag.
The 8'x8' region for the list of sources generated on-board covers 100% of the
BAT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.101.
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/)
GCN Circular 34067
Subject
Swift GRB 230622A: Global MASTER-Net observations report
Date
2023-06-22T19:12:52Z (2 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko,
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),
D. Buckley
(South African Astronomical Observatory),
O.A. Gres, N.M. Budnev
(Irkutsk State University, API),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),
A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov
(Blagoveschensk Educational State University)
MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB 230622A ( A. Melandri et al., GCN 34058) errorbox 24809 sec after notice time and 25243 sec after trigger time at 2023-06-22 17:05:04 UT, with upper limit up to 17.1 mag. The observations began at zenith distance = 84 deg. The sun altitude is -17.1 deg.
The galactic latitude b = -23 deg., longitude l = 6 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2226200
We obtain a following upper limits.
Tmid-T0 | Site |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________
497 | MASTER- | C | 90 | 16.9 |
617 | MASTER- | C | 110 | 17.2 |
762 | MASTER- | C | 140 | 17.3 |
937 | MASTER- | C | 170 | 17.2 |
1132 | MASTER- | C | 180 | 17.3 |
1332 | MASTER- | C | 180 | 17.2 |
1532 | MASTER- | C | 180 | 16.6 |
1732 | MASTER- | C | 180 | 17.3 |
1931 | MASTER- | C | 180 | 17.3 |
2132 | MASTER- | C | 180 | 17.3 |
2356 | MASTER- | C | 180 | 17.3 |
2556 | MASTER- | C | 180 | 17.3 |
2757 | MASTER- | C | 180 | 17.3 |
2957 | MASTER- | C | 180 | 17.2 |
3296 | MASTER- | C | 180 | 17.3 |
25333 | MASTER-SAAO | C | 180 | 16.9 |
25533 | MASTER-SAAO | C | 180 | 17.1 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 34069
Subject
GRB 230622A: Swift-XRT refined Analysis
Date
2023-06-23T13:16:44Z (2 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
A. Melandri (INAF-OAR), A. D'Ai (INAF-IASFPA), J.A. Kennea (PSU), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), E. Ambrosi (INAF-IASFPA), V. D'Elia (SSDC & INAF-OAR) reports on behalf of the Swift-XRT team:
We have analysed 3.9 ks of XRT data for GRB 230622A, from 383 s to 27.0
ks after the BAT trigger. The data are entirely in Photon Counting
(PC) mode. Using 105 s of PC mode data and 1 UVOT image, we find an
enhanced XRT position (using the XRT-UVOT alignment and matching UVOT
field sources to the USNO-B1 catalogue): RA, Dec = 292.51735, -32.97036
which is equivalent to:
RA (J2000): 19h 30m 04.16s
Dec(J2000): -32d 58' 13.3"
with an uncertainty of 5.4 arcsec (radius, 90% confidence).
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01176135.
This circular is an official product of the Swift-XRT team.
GCN Circular 34070
Subject
GRB 230622A: ATCA rapid radio follow-up
Date
2023-06-23T13:30:09Z (2 years ago)
From
Gemma Anderson at Curtin U <gemma.anderson@curtin.edu.au>
G. E. Anderson (Curtin), J. K. Leung (USyd), A. J. van der Horst (GWU), L. Rhodes (Oxford), A. Gulati (USyd), S. Chastain (UNM) on behalf of the PanRadio GRB collaboration
The Australia Telescope Compact Array (ATCA) rapidly performed radio observations of the long GRB 230622A (Melandri et al. GCN 34058) at 5.5 and 9 GHz as part of the Large ATCA “PanRadio GRB” follow-up programme C3542 (PI. Anderson). ATCA was on target observing at 11:30 UT, just 1.5 hrs post-burst and observed for 10 hrs. Only 4 of the usual 6 antennas were available. Due to poor observing conditions, only ~6 hrs of data at each frequency were imaged. There is no radio source coincident with the enhanced XRT position (Evans et al. GCN 34069) with a 3 sigma upper limit of 54 and 48 microJy/beam at 5.5 and 9.0 GHz, respectively. Further observations are planned.
We thank the CSIRO Space and Astronomy staff for supporting these observations and maintaining the ATCA rapid-response observing mode.
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 34082
Subject
GRB 230622A: Swift-BAT refined analysis
Date
2023-06-26T16:15:20Z (2 years ago)
From
Sibasish Laha at GSFC <sibasish.laha@nasa.gov>
D. M. Palmer (LANL), C. B. Markwardt (GSFC),
S. D. Barthelmy (GSFC), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa),,
T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU),
M. Stamatikos (OSU) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 230622A (trigger #1176135)
(Melandri, et al., GCN Circ. 34058). The BAT ground-calculated position is
RA, Dec = 292.516, -32.972 deg which is
RA(J2000) = 19h 30m 03.8s
Dec(J2000) = -32d 58' 20.6"
with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 30%.
The BAT light curve shows a complex structure with a duration of ~ 20 sec.
The second soft peak at T~24 sec is probably due to calibration and/or instrument effects, and possibly not related to the GRB.
T90 (15-350 keV) is 18.37 +- 13.63 sec (estimated error including systematics).
The time-averaged spectrum from T-0.06 to T+23.88 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
2.52 +- 0.43. The fluence in the 15-150 keV band is 4.1 +- 1.0 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T+0.05 sec in the 15-150 keV band
is 2.8 +- 0.4 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/1176135/BA/