GRB 200228B
GCN Circular 27318
Subject
GRB 200228B: continued optical observations
Date
2020-03-05T18:07:39Z (6 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Pozanenko (IKI), S. Belkin (IKI), R. Ya. Inasaridze (AbAO), E.
Klunko (ISTP), A. Kusakin (FAPHI), I. Reva (FAPHI), V. Rumyantsev
(CrAO), E. Mazaeva (IKI), A. Volnova (IKI) report on behalf of IKI-GRB-FuN:
We continue observations of the OT (Pozanenko et al., GCN 27276)
associated with GRB 200228B (Laha et al., GCN 27254; Fermi GBM Team, GCN
27253) with AZT-33IK 1.5-m telescope of Sayan observatory (Mondy) and
AS-32 telescope of Abastumani Astrophysical observatory. The OT is well
observable (see photometry below in the table) and current XRT position
( https://www.swift.ac.uk/xrt_positions/00958733/ ) coincides with
position of the OT.
Preliminary photometry of the object following.
Date UT start t-T0 Filter Exp. OT Err UL(3sigma) telescope
(mid, days) (s)
2020-03-03 01:36:36 3.6186 R 58*60 21.65 0.13 22.6 AS-32
2020-03-03 21:03:33 4.4228 R 20*120 22.2 0.4 22.0 AZT-33IK
2020-03-04 23:44:59 5.5488 R 80*60 21.93 0.17 22.6 AS-32
Photometry is based on the USNO-B2.0 nearby stars used in previous
observations (GCN 27276).
The light curve in R-filter is available at
http://grb.rssi.ru/GRB200228B/GRB200228B_lc_2.png
We urge on spectroscopic and multicolor photometry to classify the OT.
GCN Circular 27276
Subject
GRB 200228B: Mondy, TSHAO, AbAO and CrAO optical observations, afterglow candidate
Date
2020-03-01T15:21:19Z (6 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Pozanenko (IKI), S. Belkin (IKI), E. Klunko (ISTP), A. Kusakin
(FAPHI), I. Reva (FAPHI), V. Rumyantsev (CrAO), R. Ya. Inasaridze
(AbAO), E. Mazaeva (IKI), A. Volnova (IKI) report on behalf of IKI-GRB-FuN:
We observed the field of GRB 200228B (Laha et al., GCN 27254; Fermi GBM
Team, GCN 27253) with AZT-33IK 1.5-m telescope of Sayan observatory
(Mondy) starting on Feb. 28 (UT) 19:24:43. We detected an optical object
near the enhanced XRT position of the XRT afterglow (Evans et al., GCN
27256). The object is absent in the Pan-STARRS DR1 catalog. The
coordinates of the object are (J2000) 16:48:10.88 +16:59:04.5 with
uncertainty of 0.5 arcsec in both coordinates. Next we observed the
filed with Zeiss-1000 1-m telescope of Tien Shan Astronomical
Observatory starting on Feb. 28 (UT) 23:08:56, Abastumani starting on
Feb. 29 (UT) 01:38:45, Tien Shan Astronomical Observatory starting on
Feb. 29 (UT) 23:08:56, and CrAO starting on Mar. 01 (UT) 00:58:28.
Preliminary photometry of the object and the field is following.
Date UT start t-T0 Filter Exp. OT Err UL(3sigma) telescope
(mid, days) (s)
2020-02-28 19:24:43 0.351 R 15*120 21.8 0.3 21.7 AZT-33IK
2020-02-28 23:08:56 0.516 R 3480 n/d n/d 22.3 Z-1000
2020-02-29 01:38:45 0.616 R 46*60 n/d n/d 21.8 AS-32
2020-02-29 22:22:37 n/a R 5040 n/a n/a n/a Z-1000
2020-03-01 00:58:28 1.594 R 31*120 22.05 0.09 23.8 ZTSh
Photometry is based on the USNO-B2.0 nearby stars.
USNO-B1.0 R2
1069-0297786 18.42
1069-0297719 18.25
1069-0297797 14.78
The finding chart is available at
http://193.232.11.154/GRB200228B/GRB200228B_AZT33IK_Z1000_ZTSh_FC.png
(or
http://grb.iki.rssi.ru/GRB200228B/GRB200228B_AZT33IK_Z1000_ZTSh_FC.png ).
We suggest this object is a candidate in the afterglow of GRB 200228B
after at least two epoch detections (see above), possible variability
and absence of the bright object (R ~ 22) in the Pan-STARRS DR1.
We did not detect any object at the position of NIR- candidate (Perley
and Cockeram, GCN 27271).
GCN Circular 27274
Subject
GRB 200228B: LCO Optical Upper Limit
Date
2020-03-01T11:29:15Z (6 years ago)
From
Robert Strausbaugh at U. of the Virgin Islands <robert.strausbaugh@uvi.edu>
R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (U. of the Virgin Islands/College of Marin) report on behalf of a larger collaboration:
We observed Swift GRB 200228B (Laha et al., GCN 27254) with the LCO 1-m Sinistro instrument at the McDonald Observatory, Texas, USA site, on February 29, from 10:52 to 11:42 UT (corresponding to 23.4 to 24.5 hours after the GRB trigger time) with the Bessel I and R filters.
We performed a series of 10x120s exposures in I and R. We do not detect any uncatalouged sources in the individual frames (nor in stacked images) in the Swift error region. Using the USNO-B.1 catalog as reference, we obtain the following 3-sigma upper limits in stacked images:
R > 22.08
I > 20.77
R.S. is funded by NSF AST grant #1831682
GCN Circular 27273
Subject
GRB 200228B: Swift-BAT refined analysis
Date
2020-02-29T23:49:33Z (6 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):
Using the data set from T-240 to T+297 sec from the recent telemetry
downlink,
we report further analysis of BAT GRB 200228B (trigger #958733)
(Laha et al., GCN Circ. 27254). The BAT ground-calculated position is
RA, Dec = 252.007, 16.964 deg which is
RA(J2000) = 16h 48m 01.8s
Dec(J2000) = +16d 57' 50.3"
with an uncertainty of 2.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 31%.
The mask-weighted light curve shows a weak pulse that starts at ~T-1 s,
peaks at ~T+2 s, and ends at ~T+7 s. T90 (15-350 keV) is 7.37 +- 1.58 sec
(estimated error including systematics).
The time-averaged spectrum from T-0.84 to T+6.97 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
2.27 +- 0.36. The fluence in the 15-150 keV band is 3.0 +- 0.6 x 10^-7
erg/cm2.
The 1-sec peak photon flux measured from T+1.32 sec in the 15-150 keV band
is 1.0 +- 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/958733/BA/
GCN Circular 27272
Subject
GRB 200228B: RATIR Optical Observations
Date
2020-02-29T15:51:14Z (6 years ago)
From
Rosa Leticia Becerra Godinez at Inst. de Astronoma,UNAM <rbecerra@astro.unam.mx>
Rosa L. Becerra (UNAM), Alan M. Watson (UNAM), Nat Butler (ASU),
Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM),
Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino
Cucchiara
(UVI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico
Ramirez-Ruiz (UCSC), Jes��s Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM),
Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and
Vicki Toy (UMD) report:
We observed the field of GRB 200228B (Fermi GBM team, GCN 27253,
Laha, et. al. GCN 27254) with the Reionization and Transients Infrared
Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the
Observatorio Astron��mico Nacional on Sierra San Pedro M��rtir from 2020/02
29.36
to 2020/02 29.53 UTC (21.40 to 25.38 hours after the BAT trigger), obtaining
a total of 2.27 hours exposure in the r and i bands.
For a source within the Swift-XRT enhanced error circle (Evans et al., GCN
Circ. 27256),
in comparison with the SDSS DR9 and 2MASS catalogs, we obtain the following
upper
limits (3-sigma):
r > 23.19
i > 23.11
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.
We thank the staff of the Observatorio Astron��mico Nacional in San Pedro
M��rtir.
GCN Circular 27271
Subject
GRB 200228B: Liverpool Telescope imaging
Date
2020-02-29T13:57:42Z (6 years ago)
From
Daniel Perley at Liverpool JMU <d.a.perley@ljmu.ac.uk>