GRB 200227A
GCN Circular 27265
Subject
GRB 200227A: RATIR Optical Observations
Date
2020-02-28T20:22:19Z (6 years ago)
From
Alan M Watson at UNAM <alan@astro.unam.mx>
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 200227A (Laha et al., GCN Circ. 27234) 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 28.17 to 2020/02 28.24
UTC (20.84 to 22.53 hours after the BAT trigger), obtaining a total of
0.69 hours exposure in the r and i bands.
For a source within the Swift-XRT enhanced error circle (Beardmore et
al., GCN Circ. 27243), in comparison with the SDSS DR9, we obtain the
following upper limits (3-sigma):
r > 19.73
i > 20.33
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 27257
Subject
GRB 200227A: Mondy optical upper limit
Date
2020-02-28T14:30:50Z (6 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), A. Pozanenko (IKI), E. Klunko (ISTP), E. Mazaeva (IKI),
A. Volnova (IKI) report on behalf of IKI-GRB-FuN:
We observed the field of GRB 200227A (Fermi GBM Team et al., GCN 27233;
Laha et al., GCN 27234) with AZT-33IK telescope of Sayan observatory
(Mondy) starting on Feb. 27 (UT) 12:47:07. Within enhanced Swift-XRT
position of afterglow (Beardmore et al., GCN 27243) we did not detect
optical
afterglow in agreement with previously reported non-detection (Oeda et
al., GCN 27236; Oates et al., GCN 27244). Preliminary photometry of the
field is following.
Date UT start, t-T0 Filter Exp. OT UL(3sigma)
(mid, days) (s)
2020-02-27 12:47:07 0.24582 R 27*120 n/d 23.2
Photometry is based on the SDSS-DR12 nearby stars (Lupton���s transformation)
SDSS-DR12_id R(Lupton)
J034542.04+092727.3 18.56
J034546.87+092955.7 17.19
J034534.13+092646.2 17.32
GCN Circular 27251
Subject
GRB 200227A: Insight-HXMT/HE detection
Date
2020-02-28T08:57:43Z (6 years ago)
From
Qi Luo at IHEP <luoqi@ihep.ac.cn>
Q. Luo, Y. G. Zheng, C. Cai, S. Xiao, Q. B. Yi, Y. F. DU, W. C. Xue,
Y. Huang, C. K. Li, G. Li, X. B. Li, J. Y. Liao, S. L. Xiong,
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang,
Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin,
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song,
M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:
At 2020-02-27T07:20:16.15 (T0), Insight-HXMT/HE detected
GRB 200227A (trigger ID: HEB200227305) in a routine search of the data,
which was also detected by Fermi/GBM (GCN #27233) and Swift-BAT
(GCN #27234).
The Insight-HXMT/HE light curve mainly consists of two
pulses with a duration (T90) of 37.71 s measured from T0-6.92 s.
The 1-ms peak rate, measured from T0+1.169 s, is 1862 cnts/sec.
The total counts from this burst is 19259 counts.
URL_LC: http://www.hxmt.org/images/GRB/HEB200227305_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
of 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://www.hxmt.org.
GCN Circular 27249
Subject
GRB 200227A: Swift-XRT refined Analysis
Date
2020-02-28T07:49:20Z (6 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
J.A. Kennea (PSU), A.P. Beardmore (U. Leicester), J.P. Osborne (U.
Leicester), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), E.
Ambrosi (INAF-IASFPA) , A. Tohuvavohu (U. Toronto), B. Sbarufatti
(PSU) and S. Laha (GSFC/UMBC/CRESST) report on behalf of the Swift-XRT
team:
We have analysed 6.1 ks of XRT data for GRB 200227A (Laha et al. GCN
Circ. 27234), from 72 s to 29.1 ks after the BAT trigger. The data
comprise 288 s in Windowed Timing (WT) mode (the first 8 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Beardmore
et al. (GCN Circ. 27243).
The light curve can be modelled with an initial power-law decay with an
index of alpha=3.86 (+0.21, -0.16), followed by a break at T+169 s to
an alpha of 1.09 (+0.07, -0.05).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.88 (+0.08, -0.07). The
best-fitting absorption column is 5.9 (+/-0.5) x 10^21 cm^-2, in
excess of the Galactic value of 2.1 x 10^21 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.83 (+0.17, -0.16)
and a best-fitting absorption column of 5.6 (+1.1, -1.0) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 4.6 x 10^-11 (6.9 x 10^-11) erg cm^-2
count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 5.6 (+1.1, -1.0) x 10^21 cm^-2
Galactic foreground: 2.1 x 10^21 cm^-2
Excess significance: 5.7 sigma
Photon index: 1.83 (+0.17, -0.16)
If the light curve continues to decay with a power-law decay index of
1.09, the count rate at T+24 hours will be 4.8 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.2 x
10^-13 (3.3 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00958592.
This circular is an official product of the Swift-XRT team.
GCN Circular 27246
Subject
GRB 200227A: Swift-BAT refined analysis
Date
2020-02-28T05:04:40Z (6 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@milkyway.gsfc.nasa.gov>
J. R. Cummings (CPI), S. D. Barthelmy (GSFC), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):
Using the data set from T-61 to T+243 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 200227A (trigger #958592)
(Laha, et al., GCN Circ. 27234). The BAT ground-calculated position is
RA, Dec = 56.433, 9.489 deg, which is
RA(J2000) = 03h 45m 43.9s
Dec(J2000) = +09d 29' 22.0"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 46%.
The mask-weighted light curve a couple overlapping peaks starting
at T-10 sec, peaking at T+8 sec, and ending at T+90 sec.
T90 (15-350 keV) is 32.8 +- 9.7 sec (estimated error including systematics).
The time-averaged spectrum from T-0.50 to T+87.64 sec is best fit by a power law
with an exponential cutoff. This fit gives a photon index 1.15 +- 0.19,
and Epeak of 156.4 +- 88.9 keV (chi squared 55.3 for 56 d.o.f.). For this
model the total fluence in the 15-150 keV band is 7.1 +- 0.2 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T+8.54 sec in the 15-150 keV band is
5.7 +- 0.4 ph/cm2/sec. A fit to a simple power law gives a photon index
of 1.46 +- 0.05 (chi squared 63.6 for 57 d.o.f.). 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/958592/BA/
GCN Circular 27244
Subject
GRB 200227A: Swift/UVOT Upper Limits
Date
2020-02-27T21:16:21Z (6 years ago)
From
Samantha Oates at MSSL <samantha.oates@alumni.ucl.ac.uk>
S. R. Oates (U. Birmingham) and S. Laha (GSFC/UMBC/CRESST)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 200227A
93 s after the BAT trigger (Laha et al., GCN Circ. 27234).
No optical afterglow consistent with the XRT position
(Beardmore et al. GCN Circ. 27243)
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 first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 93 243 147 >20.3
u_FC 305 555 246 >19.7
white 93 1185 353 >20.8
v 634 1235 78 >18.3
b 560 1160 58 >19.2
u 305 1135 285 >19.8
w1 685 1284 58 >18.4
m2 659 1259 78 >18.4
w2 610 1210 78 >18.6
The magnitudes in the table are not corrected for the Galactic extinction
due to the significant reddening of E(B-V) = 0.28 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 27243
Subject
GRB 200227A: Enhanced Swift-XRT position
Date
2020-02-27T19:23:57Z (6 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester)
report on behalf of the Swift-XRT team.
Using 702 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 200227A, 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 = 56.43275, +9.48230 which is equivalent
to:
RA (J2000): 03h 45m 43.86s
Dec (J2000): +09d 28' 56.3"
with an uncertainty of 2.5 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 27239
Subject
GRB 200227A: Fermi GBM observation
Date
2020-02-27T14:19:53Z (6 years ago)
From
Elisabetta Bissaldi at INFN,Bari <elisabetta.bissaldi@ba.infn.it>
E. Bissaldi (Politecnico and INFN Bari)
reports on behalf of the Fermi GBM Team:
"At 07:20:08.70 UT on 27 February 2020, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 200227A (trigger 604480813 / 200227306),
which was also detected by the Swift/BAT (Laha et al. 2020, GCN 27234).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 19 degrees.
The GBM light curve shows a single broad peak
with a duration (T90) of about 24 s (50-300 keV).
The time-averaged spectrum from T0 to T0+24 s is
adequately fit by a Band function with
Epeak = 139 +/- 10 keV, alpha = -0.95 +/- 0.05,
and beta = -2.28 +/- 0.11.
The event fluence (10-1000 keV) in this time interval is
(1.41 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+7.1 s in the 10-1000 keV band
is 8.8 +/- 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 27236
Subject
GRB 200227A: MITSuME Akeno optical upper limit
Date
2020-02-27T11:59:48Z (6 years ago)
From
Motoki Oeda at Tokyo Inst. of Tech. <oeda@hp.phys.titech.ac.jp>
M. Oeda, R. Adachi, K. L. Murata, K. Shiraishi, K. Iida, M. Niwano, F.
Ogawa, S. Toma, R. Hosokawa, N. Nakamura, Y. Yatsu, and N.
Kawai(TokyoTech) report on behalf of the MITSuME collaboration:
We searched for the optical counterpart of GRB 200227A (Fermi GBM Team
et al.,GCN Circular #27233, S. Laha et al., GCN Circular #27234) with
the optical three color (g���, Rc, and Ic) CCD cameras attached to the
MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan.
The observation started on 09:05:08 UT. We did not find any new point
sources within the Swift/XRT circle (S. Laha et al., GCN Circular
#27234) in all three bands.
We obtained the 5-sigma limits as follows.
T0+[hour] MID-UT T-EXP[sec] 5-sigma limits
------------------------------------------------------------------------------------------------
2.2 09:41:13 900 g���>18.4,Rc>18.2,Ic>17.5
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used UCAC4 catalog for flux calibration.
The magnitudes are expressed in the AB system.
The images were processed in real-time through the MITSuME GPU
reduction pipeline (Niwano et al. ,in prep;
https://github.com/MNiwano/Eclair)
GCN Circular 27234
Subject
GRB 200227A: Swift detection of a burst
Date
2020-02-27T07:37:50Z (6 years ago)
From
Sibasish Laha at GSFC <sib.laha@gmail.com>
S. Laha (GSFC/UMBC/CRESST), C. Gronwall (PSU), N. J. Klingler (PSU),
A. Y. Lien (GSFC/UMBC), K. L. Page (U Leicester) and
A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift
Observatory Team:
At 07:20:08 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 200227A (trigger=958592). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 56.436, +9.491 which is
RA(J2000) = 03h 45m 45s
Dec(J2000) = +09d 29' 27"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a complex
structure with a duration of about 40 sec. The peak count rate
was ~4500 counts/sec (15-350 keV), at ~8 sec after the trigger.
The XRT began observing the field at 07:21:30.1 UT, 82.2 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 56.43302, 9.48264 which is
equivalent to:
RA(J2000) = 03h 45m 43.92s
Dec(J2000) = +09d 28' 57.5"
with an uncertainty of 3.5 arcseconds (radius, 90% containment). This
location is 31 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 2.12
x 10^21 cm^-2 (Willingale et al. 2013).
The initial flux in the 2.5 s image was 3.08e-09 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 93 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 100% of
the XRT 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
XRT 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
0.27.
Burst Advocate for this burst is S. Laha (sib.laha AT gmail.com).
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 27233
Subject
GRB 200227A: Fermi GBM Final Real-time Localization
Date
2020-02-27T07:30:29Z (6 years ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
The Fermi GBM team reports the detection of a likely LONG GRB
At 07:20:08 UT on 27 Feb 2020, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 200227A (trigger 604480813.702942 / 200227306).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 56.9, Dec = 6.3 (J2000 degrees, equivalent to J2000 03h 47m, 6d 17'), with a statistical uncertainty of 1.0 degrees.
The angle from the Fermi LAT boresight is 19.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200227306/quicklook/glg_skymap_all_bn200227306.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200227306/quicklook/glg_healpix_all_bn200227306.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200227306/quicklook/glg_lc_medres34_bn200227306.gif