GRB 210217A
GCN Circular 29591
Subject
GRB 210217A: 3.6m DOT optical observations
Date
2021-03-01T07:26:44Z (5 years ago)
From
Dimple Panchal at ARIES, India <dimplepanchal96@gmail.com>
Dimple (ARIES), K. Misra (ARIES), A. Ghosh (ARIES), R. Gupta (ARIES), A.
Kumar (ARIES), B. Kumar (ARIES), S.B. Pandey (ARIES) report:
We carried out the follow-up observations of GRB 210217A ( Simpson et al.
GCN #29521) with Aries Devasthal Faint Object Spectrograph and Camera
(ADFOSC) mounted on the 3.6m Devasthal Optical Telescope (DOT) at Devasthal
observatory of Aryabhatta Research Institute of observational sciencES
(ARIES), India. We detected the optical afterglow (Simpson et al. GCNs
#29521,29555; Zhu et al. GCN #29523; Zheng et al. GCN #29533; Shrestha et
al. GCN #29535; Kumar et al., GCN #29539) at ~ 1.7 days after the burst.
Preliminary photometry is following :
Date UT start Filter Exp. (s) Mag err
2021-02-19 15:47:38 r 4*900 22.32 0.17
2021-02-20 16:30:35 r 10*300 >22.60 ----
The reported magnitudes are calibrated with the nearby PanSTARRS field and
are not corrected for Galactic extinction in the direction of the burst.
Using our data along with the data taken from Zhu et al. GCN #29523; Zheng
et al. GCN #29533; Kumar et al., GCN #29539, we obtain a decay index of
0.47 +- 0.03 consistent with the value quoted by Shrestha et al. # GCN
29535.
.
GCN Circular 29577
Subject
GRB 210217A: Mondy optical observations
Date
2021-02-26T18:35:21Z (5 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
N.Pankov (HSE), S. Belkin (IKI), A. Pozanenko (IKI), E. Klunko (ISTP)
report on behalf of IKI GRB FuN:
We observed the field of GRB 210217A (Simpson et al., GCN 29521) with
AZT-33IK telescope of Sayan observatory (Mondy) on 2021-02-19 and XX.
Within enhanced XRT position (Evans et al., GCN 29525) we do not detect
afterglow (Simpson et al., GCNs 29521,29555; Zhu et al., GCN 29523;
Zheng et al., GCN 29533; Shrestha et al., GCN 29535; Kumar et al., GCN
29539). Preliminary photometry of the filed is following
Date UT start t-T0 Filter Exp. OT Err. UL(3sigma)
(mid, days) (s)
2021-02-19 13:10:59 1.58579 R 2190 n/d n/d 22.2
2021-02-21 16:05:26 3.71250 R 3150 n/d n/d 22.8
2021-02-19+2021-02-21 2.65193 R 5850 n/d n/d 22.9
The photometry is based on the nearby USNO-B1.0 star
USNO-B1.0_id R2
1587-088041 17.94
A light curve of afterglow of GRB 210217A (based on published
photometry) and upper limits can be found in
http://grb.rssi.ru/GRB210217A/GRB210217A_LC.jpg
Using upper upper limit we may suggest a possible jet break of the
light curve we may suggest a jet break between 1.58 and 3.71 days after
power law decay with index alpha of -0.48 (Shrestha et al., GCN 29535).
GCN Circular 29555
Subject
GRB 210217A: Swift/UVOT Detection
Date
2021-02-23T14:27:28Z (5 years ago)
From
Kira Simpson at PSU <kira.simpson1984@gmail.com>
GRB 210217A: Swift/UVOT Detection
K. K. Simpson (PSU) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 210217A
103 s after the BAT trigger (Simpson et al., GCN Circ. 29521).
A source consistent with the XRT position
*** POSITION REFERENCE is GCN_Notice ***
is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 06:30:19.90 = 97.58291 (deg.)
Dec (J2000) = +68:43:30.6 = 68.72517 (deg.)
with an estimated uncertainty of 0.46 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
white 103 253 147 18.80 +/- 0.06
u 315 508 190 18.64 +/- 0.11
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.102 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 29539
Subject
GRB 210217A: 1.3m DFOT optical detection
Date
2021-02-19T19:32:22Z (5 years ago)
From
Amit Kumar at ARIES, India <amitkundu515@gmail.com>
Amit Kumar (ARIES), Rahul Gupta (ARIES), Ankur Ghosh (ARIES), Dimple
(ARIES), Tushar Tripathi (ARIES), Shubham Kishore (ARIES), Amar Aryan
(ARIES), Shashi B. Pandey (ARIES), Brajesh Kumar (ARIES), and Kuntal Misra
(ARIES) report:
We observed the optical afterglow of the Swift detected GRB 210217A
(Simpson et al. GCN 29521; Evans et al., GCN 29525) with the 1.3m Devsthal
Fast Optical Telescope (DFOT) at Aryabhatta Research Institute of
Observational Sciences (ARIES), Nainital (India), on 2021-02-18 from UT
17:31:22 to 19:09:31 (corresponding to 18.094 to 19.730 hours from the GRB
trigger time). We observed a series of 30x120s exposures in the Bessel R
filter and a series of 20x120s exposures in the Bessel I filter. We clearly
detected the optical afterglow of GRB 210217A in the stacked frames within
the Swift XRT error circle (Simpson et al. GCN 29521) as also reported by
Zhu et al., GCN 29523; Zheng & Filippenko GCN 29533; Shrestha et al. GCN
29535.
The estimated preliminary magnitudes are as follows:
T_start-T0 (hours) Start Date (UTC) Filter Magnitude (mag)
-----------------------------------------------------------
-----------------------------------------------------------
18.09 2021-02-18T17:31:22 R 21.80 +- 0.08
19.73 2021-02-18T19:09:31 I 21.56 +- 0.12
The magnitudes are not corrected for the Galactic extinction in the
direction of the burst. Photometric calibration is performed using the
standard stars from the USNO-B1.0 catalog.
This circular may be cited.
GCN Circular 29538
Subject
GRB 210217A: Swift-XRT refined Analysis
Date
2021-02-19T02:58:08Z (5 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
D.N. Burrows (PSU), P.A. Evans (U. Leicester), J.P. Osborne (U.
Leicester), K.L. Page (U. Leicester), P. D'Avanzo (INAF-OAB), M.G.
Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , J. D. Gropp (PSU),
J.A. Kennea (PSU) and K.K. Simpson report on behalf of the Swift-XRT
team:
We have analysed 6.8 ks of XRT data for GRB 210217A (Simpson et al. GCN
Circ. 29521), from 109 s to 80.4 ks after the BAT trigger. The data
are entirely in Photon Counting (PC) mode. The enhanced XRT position
for this burst was given by Evans et al. (GCN Circ. 29525).
The light curve can be modelled with a power-law decay with a decay
index of alpha=0.79 (+/-0.05).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.97 (+0.23, -0.22). The
best-fitting absorption column is 2.5 (+0.9, -0.8) x 10^21 cm^-2, in
excess of the Galactic value of 8.7 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 3.7 x 10^-11 (5.1 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 2.5 (+0.9, -0.8) x 10^21 cm^-2
Galactic foreground: 8.7 x 10^20 cm^-2
Excess significance: 3.3 sigma
Photon index: 1.97 (+0.23, -0.22)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01033264.
This circular is an official product of the Swift-XRT team.
GCN Circular 29536
Subject
Fermi GBM Sub-Threshold Detection of GRB 210217A
Date
2021-02-18T22:22:40Z (5 years ago)
From
Joshua Wood at MSFC/Fermi-GBM <joshua.r.wood@nasa.gov>
C. Fletcher (USRA) reports on behalf of the Fermi-GBM Team:
Swift-BAT detected GRB 210217A at 23:25:42 UT (GCN 29521). There was no
Fermi-GBM onboard trigger around the event.
An automated, blind search for short gamma-ray bursts below the onboard
triggering threshold in Fermi-GBM identified a high reliability transient
consistent in both time and location with the Swift BAT event.
Link: https://gcn.gsfc.nasa.gov/notices_gbm_sub/635297147.fermi
The GBM targeted search [1], the most sensitive, coherent search for
GRB-like signals also identified a transient most significantly on the 1.024 s
timescale, with a log likelihood ratio of 72 and a location consistent with
the Swift BAT event. The GBM targeted search event was found with the highest
significance with a "normal" spectrum (Band function with
Epeak = 230 keV, alpha = -1.0, beta = -2.3) for a GRB.
[1] Goldstein et al. 2019 arXiv:1903.12597
GCN Circular 29535
Subject
GRB 210217A: Liverpool Telescope First Hour Observations
Date
2021-02-18T22:17:33Z (5 years ago)
From
Manisha Shrestha at Liverpool John Moores U <m.shrestha@ljmu.ac.uk>
M. Shrestha (Liverpool JMU), R. Smith (LJMU) , A. Melandri (INAF), I.A. Steele (LJMU), S. Kobayashi (LJMU), C. Mundell (Univ. Bath), A. Gomboc (Univ. Nova Gorica), C. Guidorzi (Univ. Ferrara) report on behalf of a wider collaboration:
We observed the field of Swift GRB 210217A (GCN 29521) with the 2.0m Liverpool Telescope (LT), La Palma on 2021 Feb 17 starting at 23:28:51.056 UT
using the IO:O optical camera in the r�, i�, and z� bands. Data were calibrated with respect to nearby APASS secondary standard stars for r� and i� bands
and SDSS secondary standard stars for z� band. We confirm the optical counterpart reported by Swift UVOT and NEXT (GCN 29523).
At T=194 seconds after the BAT trigger time, we measure r� = 18.51 +/- 0.3 mag which is close to 18.6 +/- 0.2 mag detected by NEXT team (GCN 29523).
The r� band light curve made with IO:O observations show a power law decay over the first hour in flux vs time with alpha = 0.48.
At T = 690 seconds after the BAT trigger time, we measure i� = 18.77 +/- 0.1 mag and at T = 868 seconds after the trigger we measure z� = 18.67 +/-0.1 mag.
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GCN Circular 29534
Subject
GRB 210217A: Swift-BAT refined analysis
Date
2021-02-18T18:01:32Z (5 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
T. Sakamoto (AGU), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
K. K. Simpson (PSU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (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 210217A (trigger #1033264)
(Simpson et al., GCN Circ. 29521). The BAT ground-calculated position is
RA, Dec = 97.578, 68.715 deg which is
RA(J2000) = 06h 30m 18.6s
Dec(J2000) = +68d 42' 55.4"
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 30%.
The mask-weighted light curve shows a single-peaked FRED-like structure
that starts and peaks at ~T0, and ends at ~T+5 s. T90 (15-350 keV) is
4.22 +- 1.15 sec (estimated error including systematics).
The time-averaged spectrum from T-0.65 to T+4.89 sec is best fit by
a simple power-law model. The power law index of the time-averaged
spectrum is 2.01 +- 0.16. The fluence in the 15-150 keV band
is 6.8 +- 0.7 x 10^-7 erg/cm2. The 1-sec peak photon flux measured
from T-0.13 sec in the 15-150 keV band is 5.1 +- 0.5 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/1033264/BA/
GCN Circular 29533
Subject
GRB 210217A: KAIT Optical Observations
Date
2021-02-18T17:57:39Z (5 years ago)
From
Weikang Zheng at UC Berkeley <weikang@berkeley.edu>
WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on
behalf of the KAIT GRB team:
The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory, responded to the Swift GRB 210217A (Simpson et al.,
GCN 29521) starting at ~4.27 hours after the Swift trigger.
A total of 30x60s images were obtained in the clear (roughly R) filters.
We marginally detect the optical afterglow (Simpson et al., GCN 29521;
Zhu et al., GCN 29523) in the coadd image with a mag of 20.8 +/- 0.3,
calibrated to the Pan-STARRS1 catalog.
GCN Circular 29525
Subject
GRB 210217A: Enhanced Swift-XRT position
Date
2021-02-18T03:26:12Z (5 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester)
report on behalf of the Swift-XRT team.
Using 396 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 210217A, 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 = 97.58507, +68.72536 which is equivalent
to:
RA (J2000): 06h 30m 20.42s
Dec (J2000): +68d 43' 31.3"
with an uncertainty of 1.9 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 29523
Subject
GRB 210217A: NEXT early optical afterglow observations
Date
2021-02-18T00:20:00Z (5 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
Z.P. Zhu (NAOC, HUST), S.Y. Fu, X. Liu, D. Xu (NAOC), X. Gao (Urumqi
No.1 Senior High School), J.Z. Liu (XAO) report:
We observed the field of GRB 210217A (Simpson et al., GCN 29521) using
the NEXT-0.6m optical telescope located at Nanshan, Xinjiang, China.
Observations automatically started at 23:27:06 UT on 2021-02-17, i.e.,
84 s after the BAT trigger. A series of 3x40 s, 4x60 s and 10x90 s
frames in the Sloan r-filter have been obtained, and observations are
ongoing.
An uncatalogued decaying optical transient is detected at the Swift/UVOT
position (Simpson et al., GCN 29521), which is thus concluded to be the
optical afterglow of burst. The afterglow has r = 18.6 +/- 0.2 mag in
our first image, calibrated with nearby PS1 stars.
GCN Circular 29521
Subject
GRB 210217A: Swift detection of a burst with an optical counterpart
Date
2021-02-17T23:36:33Z (5 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
K. K. Simpson (PSU), J.D. Gropp (PSU), J. A. Kennea (PSU),
N. J. Klingler (PSU), N. P. M. Kuin (UCL-MSSL),
A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), M. J. Moss (GWU),
D. M. Palmer (LANL), B. Sbarufatti (PSU) and M. H. Siegel (PSU) report
on behalf of the Neil Gehrels Swift Observatory Team:
At 23:25:42 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 210217A (trigger=1033264). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 97.610, +68.715 which is
RA(J2000) = 06h 30m 26s
Dec(J2000) = +68d 42' 53"
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 ~3400 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 23:27:20.1 UT, 97.8 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source located at RA, Dec 97.58675, 68.72497 which
is equivalent to:
RA(J2000) = 06h 30m 20.82s
Dec(J2000) = +68d 43' 29.9"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 47 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 8.69
x 10^20 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 103 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 06:30:19.93 = 97.58305
DEC(J2000) = +68:43:30.6 = 68.72516
with a 90%-confidence error radius of about 0.63 arc sec. This position is 6.2
arc sec. from the center of the XRT error circle. The estimated magnitude is
18.72 with a 1-sigma error of about 0.15. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.103.
Burst Advocate for this burst is K. K. Simpson (kira.simpson1984 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/)