- GCN Notice
TITLE: GCN/MAXI NOTICE
NOTICE_DATE: Sat 04 Feb 23 22:04:39 UT
NOTICE_TYPE: MAXI Unknown Source Position
EVENT_ID_NUM: 9979708795
EVENT_RA: 197.56d {+13h 10m 15s} (J2000),
197.87d {+13h 11m 30s} (current),
196.89d {+13h 07m 33s} (1950)
EVENT_DEC: -22.04d {-22d 02' 12"} (J2000),
-22.16d {-22d 09' 33"} (current),
-21.77d {-21d 46' 15"} (1950)
EVENT_ERROR: 1.0 [deg radius, stat+sys, 90% containment]
EVENT_FLUX: 1289.0 +- 0.0 [mCrab]
EVENT_DATE: 19979 TJD; 35 DOY; 23/02/04
EVENT_TIME: 78491.00 SOD {21:48:11.00} UT
EVENT_TSCALE: 1s
EVENT_EBAND: Low, 2-4 keV
SUN_POSTN: 318.29d {+21h 13m 09s} -16.09d {-16d 05' 21"}
SUN_DIST: 110.24 [deg]
MOON_POSTN: 130.27d {+08h 41m 04s} +23.44d {+23d 26' 31"}
MOON_DIST: 80.00 [deg]
MOON_ILLUM: 99 [%]
GAL_COORDS: 308.68, 40.62 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 204.67,-13.47 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: MAXI Unknown Source Position. GRB or unknown X-ray Transient.
- GCN Notice
TITLE: GCN/MAXI NOTICE
NOTICE_DATE: Sat 04 Feb 23 22:18:20 UT
NOTICE_TYPE: MAXI Unknown Source Position
EVENT_ID_NUM: 9979708795
EVENT_RA: 197.58d {+13h 10m 19s} (J2000),
197.89d {+13h 11m 34s} (current),
196.91d {+13h 07m 38s} (1950)
EVENT_DEC: -21.75d {-21d 45' 06"} (J2000),
-21.87d {-21d 52' 27"} (current),
-21.49d {-21d 29' 09"} (1950)
EVENT_ERROR: 1.0 [deg radius, stat+sys, 90% containment]
EVENT_FLUX: 628.0 +- 0.0 [mCrab]
EVENT_DATE: 19979 TJD; 35 DOY; 23/02/04
EVENT_TIME: 78491.00 SOD {21:48:11.00} UT
EVENT_TSCALE: 1s
EVENT_EBAND: Low, 2-4 keV
SUN_POSTN: 318.30d {+21h 13m 12s} -16.09d {-16d 05' 11"}
SUN_DIST: 110.37 [deg]
MOON_POSTN: 130.39d {+08h 41m 32s} +23.41d {+23d 24' 47"}
MOON_DIST: 79.76 [deg]
MOON_ILLUM: 99 [%]
GAL_COORDS: 308.74, 40.91 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 204.57,-13.20 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: MAXI Unknown Source Position. GRB or unknown X-ray Transient.
- GCN Circular #33265
M. Serino (AGU), W. Iwakiri (Chiba U.),
H. Negoro, M. Nakajima, K. Kobayashi, M. Tanaka, Y. Soejima (Nihon U.),
T. Mihara, T. Kawamuro, S. Yamada, T. Tamagawa, M. Matsuoka (RIKEN),
T. Sakamoto, S. Sugita, H. Hiramatsu, H. Nishikawa, A. Yoshida (AGU),
Y. Tsuboi, J. Kohara, S. Urabe, S. Nawa, N. Nemoto (Chuo U.),
M. Shidatsu, M. Iwasaki (Ehime U.),
N. Kawai, M. Niwano, R. Hosokawa, Y. Imai, N. Ito, Y. Takamatsu (Tokyo Tech),
S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, T. Kurihara (JAXA),
Y. Ueda, S. Ogawa, K. Setoguchi, T. Yoshitake, K. Inaba, Y. Nakatani (Kyoto U.),
M. Yamauchi, T. Sato, R. Hatsuda, R. Fukuoka, Y. Hagiwara, Y. Umeki (Miyazaki U.),
K. Yamaoka (Nagoya U.),
Y. Kawakubo (LSU),
M. Sugizaki (NAOC)
report on behalf of the MAXI team:
The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source
at 21:47:51 UT on 4 Feb 2023.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (197.581 deg, -21.752 deg) = (13 10 19, -21 45 07) (J2000)
with a statistical 90% C.L. elliptical error region
with long and short radii of 0.12 deg and 0.1 deg, respectively.
The roll angle of long axis from the north direction is 156.0 deg counterclockwise.
Without assumptions on the source constancy, we obtain a rectangular error box
for the transient source with the following corners.
(196.900, -21.911) deg = (13 07 36, -21 54 39) (J2000)
(196.998, -22.143) deg = (13 07 59, -22 08 34) (J2000)
(198.373, -21.637) deg = (13 13 29, -21 38 13) (J2000)
(198.273, -21.406) deg = (13 13 05, -21 24 21) (J2000)
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
The X-ray flux averaged over the scan was 628 +- 49 mCrab
(4.0-10.0keV, 1 sigma error).
There was no significant excess flux in the previous transit at 20:15 UT
with an upper limit of 20 mCrab.
- GCN Circular #33267
Jamie A. Kennea (PSU), Gayathri Raman (PSU), James DeLaunay
(UAlabama), Aaron Tohuvavohu (U Toronto) report:
Swift/BAT did not localize GRB 230204B onboard (T0:
2023-02-04T21:44:25.2 UTC, CALET trig CALET 1359582171, Fermi/GBM trig
697239872, INTEGRAL trig 10188, MAXI GCN 33265).
The CALET, INTEGRAL, and Fermi notices, distributed in near real-time,
triggered the Swift Mission Operations Center operated Gamma-ray
Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al.
2020, ApJ, 900, 1).
Upon trigger by this notice, GUANO sent a command to the Swift Burst
Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from
[-50,+150] seconds around the time of the burst. All the requested
event mode data was delivered to the ground.
The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ,
941, 169), detects the burst with a sqrt(TS) of 21.5 in a 4.096 s
analysis time bin.
The burst duration as seen by BAT is ~65 s.
NITRATES results indicate a burst coming from outside the FOV, with
DeltaLLHOut of -4.
The OFOV localization is consistent with the MAXI position for this burst.
See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief
descriptions and interpretation of sqrt(TS), DeltaLLHPeak, and
DeltaLLHOut.
GUANO is a fully autonomous, extremely low latency, spacecraft
commanding pipeline designed for targeted recovery of BAT event mode
data around the times of compelling astrophysical events to enable
more sensitive GRB searches.
A live reporting of Swift/BAT event data recovered by GUANO can be
found at: https://www.swift.psu.edu/guano/
- GCN Circular #33268
G. Waratkar (IITB), P K. Navaneeth (IUCAA), P. Shetty (IITB), A. Ahmad
(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 the bright long GRB 230204B
which was also detected by MAXI-GSC (GCN Circ. 33265), SWIFT/BAT-GUANO
(GCN Circ. 33267), along with CALET, INTEGRAL and FERMI notices.
The source was clearly detected in the 20-200 keV energy range. The
light curve showed multiple peaks of emission with the strongest peak at
2023-02-04 21:45:19.5 UTC. The measured peak count rate associated with
the burst is 175.4 (+27.7 -26.6) counts/s above the background in the
combined data of all four quadrants, with a total of 7611 (+557 -740)
counts. The local mean background count rate was 131.2 (+0.7 -0.9)
counts/s. Using cumulative rates, we measure a T90 of 216.64 (+5.13
-22.56) s. In the preliminary analysis, we find 3240 Compton events
associated with this event.
It was also 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 2023-02-04 21:45:18.7 UTC. The
measured peak count rate is 1315.9 (+79.7 -88.8) counts/s above the
background in the combined Veto data of all four quadrants, with a total
of 48625 (+1487 -1923) counts. The local mean background count rate was
1273.2 (+2.4 -1.8) counts/s. We measure a T90 of 212.32 (+2.94 -7.75) s
from the cumulative Veto light curve.
CZTI GRB detections are reported regularly on the payload site at
http://astrosat.iucaa.in/czti/?q=grb. 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.
- GCN Circular #33269
V. Swain (IITB), H. Kumar (IITB), G. Waratkar(IITB), V. Bhalerao (IITB), G.
C. Anupama(IIA), S. Barway (IIA) and K. Angail (IAO) report on behalf of
the GIT team:
We observed the field of GRB 230204B detected by MAXI (Serino et al., GCN
33265) with 0.7m GROWTH-India Telescope (GIT). We started observations at
23:22:37.597 UT, i.e., 1.57 hrs after the Swift/BAT trigger. We obtained 10
frames in the r' band of 300 sec each. We detected an uncatalogued source
at RA 13:10:34.96, Dec: -21:43:05.31 with an uncertainty of 0.67 arcsec.
There is no minor planet present at this position. The photometric results
follow as:
----------------------------------------------------------------------
JD (mid) | T_mid-T0 (hrs) | Filter | Magnitude (AB) |
----------------------------------------------------------------------
2459980.47404 | 1.57 | r' | 15.50 +/- 0.04 |
2459980.50774 | 2.38 | r' | 16.45 +/- 0.05 |
----------------------------------------------------------------------
The candidate decayed by 0.95 magnitude during our observations, separated
by a time span of 48 mins. The fast decay suggests that the candidate is
likely an afterglow of GRB 230204B. We encourage photometric for further
confirmation and spectroscopic follow-up for redshift measurement. 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 #33272
C. Casentini (INAF/IAPS), C. Pittori (SSDC, and INAF/OAR),
M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), F. Verrecchia,
F.Lucarelli
(SSDC, and INAF/OAR), A. Argan, M. Cardillo, Y. Evangelista, L. Foffano,
E. Menegoni, G. Piano (INAF/IAPS), A. Addis, L. Baroncelli, A. Bulgarelli,
A. Di Piano, V. Fioretti, G. Panebianco, N. Parmiggiani (INAF/OAS-Bologna),
M. Romani (INAF/OA-Brera), M. Marisaldi (INAF/OAS-Bologna, Bergen
University),
M. Pilia, A. Trois (INAF/OA Cagliari), F. Longo (Uni. Trieste, INFN
Trieste),
I. Donnarumma, A.Ursi (ASI), A. Giuliani (INAF/IASF-Mi) and P. Tempesta
(TeleSpazio),
report on behalf of the AGILE Team:
The AGILE satellite detected the bright and long GRB 230204B at
T0 = 2023-02-04 21:44:25.2 s (UTC), reported by MAXI/GSC, Swift/BAT-GUANO,
AstroSAT CZTI, GIT (GCNs #33265, #33267, #33268 and #33269), CALET trig
1359582171, Fermi/GBM trig 697239872 and INTEGRAL trig 10188.
The burst is clearly visible in the AGILE scientific ratemeters of the
MiniCALorimeter (MCAL; 0.4-100 MeV) and AntiCoincidence (AC; 50-200 keV)
detectors.
The event lasted about 145 s and it released a total number of 170125
counts
in the MCAL detector (above a background rate of 1418 Hz), and 468843
counts in the AC
detector (above a background rate of 3197 Hz). The AGILE ratemeters light
curves
can be found at
http://www.agilescienceapp.it/notices/GRB230204B_AGILE_RM_A.png .
The event also triggered a partial high-time resolution MCAL data
acquisition,
from T0-20 s to T0+25 s (UTC). The multi-peaked MCAL light curve can be
found
at
http://www.agilescienceapp.it/notices/GRB230204B_082123_602631919.000000.png
.
At the T0, the event was 72 deg off-axis.
Additional analysis of AGILE data is in progress. Automatic MCAL GRB alert
Notices
can be found at: https://gcn.gsfc.nasa.gov/agile_mcal.html
- GCN Circular #33273
M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner
(Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak
(Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Kolar, J.-P.
Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U.
of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo,
M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U.
of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H.
Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos
U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G.
Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi
(Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss
(Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.),
H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima
U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U.
Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.
The long-duration GRB 230204B (MAXI/GSC detection: GCN Circ. 33265;
Swift/BAT-GUANO detection: GCN Circ. 33267; AstroSat detection: GCN Circ.
33268; AGILE/MCAL detection: GCN Circ. 33272; Fermi/GBM detection: trigger
no. 697239872; CALET/GCBM detection: trigger no. 1359582171; INTEGRAL/SPI-ACS
detection: trigger no. 10188) was observed by the GRBAlpha 1U CubeSat (Pal
et al. Proc. SPIE 2020).
The detection was confirmed at the peak time 2023-02-04 21:47:03 UTC. The
T90 duration measured by GRBAlpha is 207 s and the maximum significance
during T90 reaches 25 sigma in the 110-370 keV band.
The light curve obtained by GRBAlpha is available here:
https://grbalpha.konkoly.hu/static/share/GRB230204B_GCN.pdf
All GRBAlpha detections are listed at:
https://monoceros.physics.muni.cz/hea/GRBAlpha/
GRBAlpha is a demonstration mission for a future CubeSats constellation
(Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75
x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy
range from ~50 keV to ~1000 keV. GRBAlpha was launched on 2021 March 22
from Baikonur. After its commissioning phase, the scientific observations
are now under way. To increase the duty cycle and the downlink rate, the
upgrade of the on-board data acquisition software stack is in progress. The
ground segment is also supported by the radio amateur community and it
takes advantage of the SatNOGS network for increased data downlink volume.
- GCN Circular #33276
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the MAXI GRB 230204B.
Automated analysis of the XRT data will be presented online at
https://www.swift.ac.uk/ToO_GRBs/00021535
Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the MAXI event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a
GCN Circular after manual consideration.
Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).
This circular is an official product of the Swift-XRT team.
- GCN Circular #33278
S. J. Smartt (Oxford), K. W. Smith, S. Srivastav, D. R. Young,,
M. Fulton, M. McCollum, T. Moore, J. Weston (Queen's University
Belfast), L. Shingles (GSI/QUB), L. Rhodes (Oxford), L. Denneau, J.
Tonry, H. Weiland, A. Lawrence, R. Siverd (IfA, University of Hawaii),
N. Erasmus, W. Koorts (South African Astronomical Observatory), A.
Jordan, V. Suc (UAI, Obstech), A. Rest (STScI), T.-W. Chen (TUM/MPA),
M. Nicholl (Birmingham), C. Stubbs (Harvard), J. Sommer (LMU/QUB)
We report early optical observations of the afterglow of the Maxi/GSC
discovered GRB 230204B (Serino et al. GCN 33265). The optical
afterglow was discovered by Kumar et al. (GCN 29233) at r=15.50 +/-
0.04 with a decline rate of 1.2 mag per hr. Kumar et al. reported this
optical transient discovery as AT2023bic to the Transient Name Server.
We observed the field with the ATLAS system in normal survey mode.
ATLAS is a quadruple 0.5m telescope system with two units in Hawaii,
and one each in Chile and South Africa (see Tonry et al. 2018,
PASP,130:064505). Our transient science server (Smith et al. 2020,
PASP, 132:085002) independently detected AT2023bic on the ATLAS
(Sutherland) images at coordinates RA = 13:10:34.93, Declination =
-21:43:05.1 (J2000).
Forced photometry at those coordinates results in the following AB
magnitudes in the o-band filter (a broad r+i composite filter) :
MJD Date mag dmag
59980.05525005 2023-02-05 01:19:33 17.05 0.04
59980.05708335 2023-02-05 01:22:12 17.18 0.05
59980.07028305 2023-02-05 01:41:12 17.33 0.05
59980.07343935 2023-02-05 01:45:45 17.32 0.05
We measure a decline rate of 0.6 mag per hr, approximately 2hrs after
the Kumar et al. measurement. The decline may be slowing.
We note that AT2023bic is located 108.60" N, 10.90" W from the nearby
galaxy ESO 576- G 003, at z = 0.009873 (approximately 40Mpc). This
galaxy sits within the PGC1 0045721 galaxy group (NED and Kourkchi &
Tully 2017, ApJ 843, 16). While this is likely a line of sight
coincidence, a spectroscopic redshift of AT2023bic is needed. If it
were at a distance of 40Mpc, it would be 22kpc projected offset from
ESO 576- G 003. There is no source in the Pan-STARRS 3Pi images at
this positon (Chambers et al. arXiv:1612.05560).
- GCN Circular #33281
A. Saccardi (GEPI, Paris obs.), D. A. Kann (Goethe Univ.), J. Palmerio
(GEPI, Paris obs. and IAP), V. D’Elia (SSDC and INAF-OAR), B. Schneider
(MIT), L. Izzo (DARK/NBI), A. de Ugarte Postigo (OCA), D. B. Malesani
(Radboud Univ. and DAWN/NBI) report on behalf of the Stargate collaboration:
We observed the optical afterglow of GRB 230204B (Serino et al., GCN
33265; Swain et al., GCN 33269), also known as AT 2023bic (Smartt et
al., GCN 33278), using the ESO VLT UT3 (Melipal) equipped with the
X-shooter spectrograph. Our spectra cover the wavelength range
3000-25000 AA, and consist of 4 exposures by 600 s each. The observation
mid time was 2023 Feb 6.22 UT (31.4 hr after the GRB).
In a 30 s image taken with the acquisition camera on Feb 6.19 UT, we
detect the optical afterglow, for which we measure a magnitude r = 21.55
+- 0.18 AB (calibrated against a single nearby star from the Pan-STARRS
catalog).
A faint continuum is the detected in the visible and near-infrared arms.
Several, weak absorption features can be identified, which we interpret
as due to Mg II, Mg I and Fe II at a common redshift of z = 2.142. While
individual lines have low S/N, the combined detection of multiple
features provides a convincing measurement of the redshift of this
absorption system.
The association with the PGC1 0045721 galaxy group is thus a chance
superposition, as already suggested by Smartt et al. (GCN 33278).
We acknowledge excellent support from the ESO observing staff in
Paranal, in particular Claudia Paladini and Heidi Korhonen.
- GCN Circular #33284
Amit K. Ror, Ankur Ghosh, Brajesh Kumar, Rahul Gupta, A. Aryan, Dimple, S.
B. Pandey, and K. Misra (ARIES) report:
We observed the field of GRB 230204B detected by MAXI/GSC (Serino et al.
2023, GCN 33265) using the 3.6m Devasthal Optical Telescope located at the
Devasthal observatory of the Aryabhatta Research Institute of Observational
Sciences (ARIES), Nainital, India.
We have taken multiple frames having an exposure time of 180 sec each in
the r filter. We stacked the images after the alignment. We clearly detect
the optical transient discovered by Swain and Kumar et al. 2023 (GCN 33269)
in the stacked images. The estimated preliminary magnitude is the following:
Date Start_UT T_start-T0 (days) Filter Exp time (sec) magnitude
==============================================================
2023-02-06 01:49:47.93 ~1.168 r 180 sec*10
21.04 +/- 0.04
The detection of the optical transient is consistent with the observation
of Swain and Kumar et al. 2023 (GCN 33269), Smartt et al. 2023 (GCN 33278),
and Saccardi et al. 2023 (GCN 33281)
The limiting magnitude quoted is not corrected for the galactic and host
extinctions in the direction of the transient. Photometric calibration is
performed using the standard stars from the Pan-STARRS catalog.
This circular may be cited. The 3.6m Devasthal Optical Telescope (DOT) is a
recently commissioned facility in the Northern Himalayan region of India
(long: 79 41 04E, lat: 29 21 40N, alt: 2540m) owned and operated by the
Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital (
https://www.aries.res.in). The authors of this GCN circular thankfully
acknowledge the consistent support from the staff members to run and
maintain the 3.6m DOT.
- GCN Circular #33285
V. D'Elia (SSDC & INAF-OAR), A.P. Beardmore (U. Leicester), P. D'Avanzo
(INAF-OAB), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) ,
D.N. Burrows (PSU), J. D. Gropp (PSU), S. Dichiara (PSU), J.P. Osborne
(U. Leicester) and P.A. Evans (U. Leicester) report on behalf of the
Swift-XRT team:
Swift-XRT has performed follow-up observations of the MAXI-detected
burst GRB 230204B (Serino et al. GCN Circ. 33265). A possible optical
counterpart was reported by GIT (Swain et al. GCN Circ. 33269).
Swift-XRT observations consist of 4.2 ks of Photon Counting (PC) mode
data between T0+80.5 ks and T0+97.9 ks.
One uncatalogued X-ray source has been detected consistent with the GIT
position. The source is below the RASS limit but does not show
definitive signs of fading. This is most likely the afterglow, given
also the reported redshift of z=2.14 (Saccardi et al. GCN Circ. 33281)
but further observations are required to assess for fading. Details of
this source are given below:
Source 3:
RA (J2000.0): 197.6441 = 13:10:34.58
Dec (J2000.0): -21.7164 = -21:42:58.9
Error: 7.4 arcsec (radius, 90% conf.)
Count-rate: (5.6 +/- 1.5)e-3 ct s^-1
Distance: 8 arcsec from MAXI position.
Flux: (3.8 +/- 1.0)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)
The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
https://www.swift.ac.uk/ToO_GRBs/00021535.
This circular is an official product of the Swift-XRT team.
- GCN Circular #33288
S. Poolakkil (UAH) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:
"At 21:44:27.20 UT on 4 February 2023, the Fermi Gamma-Ray Burst Monitor
(GBM)
triggered and located GRB 230204B (trigger 697239872 / 230204906)
which was also detected by the Swift/BAT-GUANO (Kennea et al. 2023, GCN
33267),
Swift-XRT (D'Elia et al. 2023, GCN 33285), MAXI/GS (Serino et al. 2023, GCN
33265),
AGILE (Casentini et al. 2023, GCN 33272), ATLAS (Smartt et al. 2023, GCN
33278),
and VLT/X-shooter (Saccardi et al. 2023, GCN 33281).
The angle from the Fermi LAT boresight at the GBM trigger time is 106
degrees.
The GBM light curve consists of multiple peaks followed
by some extended emission with a duration (T90) of about 216 s (50-300 keV).
The time-averaged spectrum from T0-1.024 s to T0+228.4 s
is best fit by a power law function with an exponential
high-energy cutoff. The power law index is -0.97 +/- 0.02 and
the cutoff energy, parameterized as Epeak, is 783 +/- 40 keV.
A Band function fits equally well, with Epeak = 763 +/- 45 keV,
alpha = -0.97 +/- 0.02 and beta = -2.73 +/- 0.29.
The event fluence (10-1000 keV) in this time interval is
(138.9 +/- 1.5)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+156 s in the 10-1000 keV band
is 7.3 +/- 0.4 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html
For Fermi GBM data and info, please visit the official Fermi GBM Support
Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"
- GCN Circular #33292
M. H. Siegel (PSU) and V. D’Elia (SSDC & INAF-OAR)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 230204B
80 ks after the MAXI trigger (Serino et al., GCN Circ. 33265).
No optical afterglow consistent with the optical or XRT positions
(Swain et al., GCN Circ. 33269, Smartt et al., GCN Circ. 33278, D’Elia et al.,
GCN Circ. 33285) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
v 81062 109630 314 >19.1
b 80652 109220 314 >20.1
u 80567 109136 314 >19.8
w1 80403 109052 629 >20.1
m2 81146 109877 2154 >20.9
w2 80737 109546 1259 >20.7
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.109 in the direction of the burst
(Schlegel et al. 1998).
- GCN Circular #33293
R. Strausbaugh (University of Minnesota), A. Cucchiara (NASA) report on
behalf of a larger collaboration:
We observed the GRB 230204B (Serino et al., GCN 33265) field with the LCOGT
1-meter Sinistro instrument at the Siding Spring Observatory, Australia
site, on February 6, from 15:27 to 16:24 UT (corresponding to 38.33 to 39.3
hours from the GRB trigger time) with the SDSS g, r, and i filters.
We performed a series of 3x300s exposures in each band. We do not detect a
source in any band at the GIT optical counterpart location (Swain et al.,
GCN 33269), evidence for additional fading compared to early optical
detections (Swain et al., GCN 33269; Smartt et al., GCN 33278; Saccardi et
al., GCN 33281; Ror et al., GCN 33284).
The following upper limits are calculated using the PanSTARRS catalog as
reference:
g > 22.0
r > 21.9
i > 21.1
These magnitudes are not corrected for galactic extinction.
- GCN Circular #33301
V.Lipunov (Lomonosov MSU), D.A.H.Buckley (SAAO), A.Chasovnikov, Ya.Kechin, A.Kuznetsov,
N.Tiurina, O.Gress, E.Gorbovskoy, G.Antipov, P.Balanutsa, K.Zhirkov, D.Vlasenko, V.Senik, D.Kuvshinov,
V.Topolev, Yu.Tselik, D.Cheryasov, I.Gorbunov (Lomonosov Moscow State University, SAI, Physics Department),
C.Francile, R. Podesta, F. Podesta (Observatorio Astronomico Felix Aguilar of San Juan National University of Argentina),
R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.Corella,L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory),
N.M.Budnev (ISU,API),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov (Blagoveschensk Educational State University)
MASTER OT J131034.94-214304.8 early detection of MAXI GRB 230204B optical
counterpart (Swain et al. GCN 33269, Smartt et al. GCN 33278, Saccardi et al. GCN 33281, Ror et al. GCN 33284, Siegel et al. GCN 33292, Strausbaugh et al. GCN 33293)
MASTER-SAAO robotic telescope (Global MASTER-Net http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, v.2010, 30L)
located in South African Astronomical Observatory,
started inspect of the MAXI GRB230204.91 (trigger 979708795, 13h10m14.88s, -22d02m13.2s, R=1deg, Serino et al. GCN 33265;
Kennea et al. GCN 33267, Waratkar et al. GCN 33268, Casentini et al. GCN 33272, Dafcikova et al. GCN 33273, D'Elia et al. GCN 33285, Poolakkil et al. GCN 33288)
errorbox 85 sec after notice time (1075 sec after trigger time) at 2023-02-04 22:06:06 UT
with upper limit to 19.4m ( unfiltered ) .
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2196693
The observations began at zenith distance = 63 deg. The sun altitude: -40.5 deg., the distance to Moon (alt=12 deg.) was 89 deg., the Moon phase 0.99). The galactic latitude b = 40 deg., longitude l = 309 deg.
MASTER-SAAO auto-detection system ( Lipunov et al., 2010 )
detected OT source at (RA, Dec) = 13h 10m 34.94s -21d 43m 04.8s at 2023-02-04.92090 UT.
The OT unfiltered magnitude at first image is 12.9m (mlim=17.6). Automatic light curve decay has pecularity.
We have reference image on 2020-04-24.82001 UT with unfiltered mlim=20.6m.
We observed this field also in very wide field cameras (MASTER-VWFC).
The reduction will be continued.
- GCN Circular #33321
Ashna Gulati (U. Sydney, CSIRO), James Leung (U. Sydney, CSIRO), David Kaplan (UWM), Tara Murphy (U. Sydney)
We observed GRB 230204B (Serino et al., GCN 33265) with the Australia Telescope Compact Array (ATCA), on 2023 February 8 from 13:00 to 23:00 UT (3.6 days after the MAXI/GSC trigger) at 5.5, 9.0, 16.7, 21.2, 33.0 and 35.0 GHz. In our preliminary analysis, we detect the radio counterpart at 16.7 GHz at a position consistent with the GIT optical counterpart position (Swain et al., GCN 33269).
Radio emission has not been detected within 1’ of the GRB position in previous radio surveys: National Radio Astronomy Observatory VLA Sky Survey (NVSS; Condon et al., 1998), Sydney University Molonglo Sky Survey (SUMSS; Mauch et al., 2003), the Rapid ASKAP Continuum Survey (RACS; McConnell et al., 2020) or the Very Large Array Sky Survey (VLASS; Lacy et al., 2019). We measured a VLASS 5-sigma upper limit of 0.69 mJy at 3GHz.
We report the ATCA detection and 5-sigma upper limits below:
Freq (GHz) | Flux Density (mJy)
—----------------------------------------
5.5 | <0.56
9.0 | <0.25
16.7 | 0.19 +/- 0.03
21.2 | <0.14
33.0 | <0.12
35.0 | <0.13
Further analysis of this data is ongoing.
We thank CSIRO staff for supporting these observations.
The Australia Telescope Compact Array is part of the Australia Telescope National Facility which is funded by the Australian Government for operation as a National Facility managed by CSIRO. We acknowledge the Gomeroi people as the traditional owners of the Observatory site.
- GCN Circular #33322
Y. Asaoka (ICRR), A. Yoshida, T. Sakamoto, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
S. Torii, Y. Akaike, K. Kobayashi (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC),
M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:
The long GRB 230204B (MAXI/GSC Detection: Serino et al., GCN Circ. 33265;
Swift/BAT-GUANO detection: Kennea et al., GCN Circ. 33267; AstroSat CZTI
detection: Waratkar et al., GCN Circ. 33268; AGILE detection: Casentini et al.,
GCN Circ. 33272; Detection by GRBAlpha: Dafcikova et al., GCN Circ. 33273;
Fermi-GBM Detection: Poolakkil et al., GCN Circ. 33288) triggered
the CALET Gamma-ray Burst Monitor (CGBM) at 21:44:25.20 UTC
on February 4, 2023
(http://cgbm.calet.jp/cgbm_trigger/flight/1359582171/index.html).
The burst signal was seen by only the SGM detector.
The burst light curve shows a double-peaked structure that starts
at T+2.3 sec, peaks at T+54.1 sec and ends at T+65.0 sec.
The T90 and T50 durations measured by the SGM data are 59.5 +/- 0.9 sec
and 11.6 +/- 0.8 sec (40-1000 keV), respectively.
The ground-processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1359582171/
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.
- GCN Circular #33333
B. O'Connor (UMD, GWU), E. Hammerstein (UMD), S.B. Cenko (UMD,
NASA-GSFC), E. Troja (UTV, ASU), S.Dichiara (PSU),
J. Durbak (UMD, NASA-GSFC), A. Kutyrev (UMD, NASA-GSFC),
S. Veilleux (UMD), I. Andreoni (UMD, NASA-GSFC), and
G. Srinivasaragavan (UMD):
We observed the field of GRB 230204B (Serino et al. GCN 33265;
Kennea et al. GCN 33267) using the Large Monolithic Imager (LMI)
on the 4.3m Lowell Discovery Telescope (LDT) at Happy Jack, AZ.
Observations began on February 13th, 2023 at 11:05:48 UT at
airmass 1.8 under seeing of ~2" with total exposure 2400 s
in i-band.
At the location of the optical counterpart (Swain et al. GCN 33269),
we do not detect any source to depth i>23.7 AB mag.
Magnitudes are calibrated against the SDSS catalog and are not
corrected for Galactic extinction.
We thank the staff of the Lowell Discovery Telescope for assistance
with these observations.
- GCN Circular #33441
V.Lipunov (Lomonosov MSU), D.A.H.Buckley (SAAO), A.Chasovnikov, Ya.Kechin,
A.Kuznetsov, N.Tiurina, O.Gress, E.Gorbovskoy, G.Antipov, P.Balanutsa,
K.Zhirkov, D.Vlasenko, V.Senik, D.Kuvshinov,
V.Topolev, Yu.Tselik, D.Cheryasov, I.Gorbunov, Ya.Kechin (Lomonosov Moscow
State University, SAI, Physics Department);
C.Francile, R. Podesta, F. Podesta (Observatorio Astronomico Felix Aguilar of
San Juan National University of Argentina),
R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.Corella,L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory),
N.M.Budnev (ISU,API),
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, v.2010, 30L)
center (Kozyrev et al. GCN 33425) at position Levan et al., GCN 33439
31 hours after trigger (22 30 43UT 1800 sec) ~20.2 (Unfiltered). The
position accuracity
is about ~ 1 pix =2".
But there is the Gaia star 3".3 offset with same magnitude.
No object in MPC.
The reduction will be continued.
Previous IAU Circulars 