GRB 200410A
GCN Circular 27518
Subject
GRB 200410A: Swift detection of a burst with a possible optical counterpart
Date
2020-04-10T02:49:58Z (5 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@milkyway.gsfc.nasa.gov>
K. K. Simpson (PSU), S. D. Barthelmy (GSFC), J.D. Gropp (PSU),
J. A. Kennea (PSU), N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC),
F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), M. H. Siegel (PSU)
and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels
Swift Observatory Team:
At 02:25:10 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 200410A (trigger=965638). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 299.637, +51.763, which is
RA(J2000) = 19h 58m 33s
Dec(J2000) = +51d 45' 48"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows multiple peaks
with a total duration of about 45 sec. The peak count rate
was ~1000 counts/sec (15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 02:26:51.7 UT, 101.3 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source with an enhanced position: RA, Dec 299.6456,
51.7813 which is equivalent to:
RA(J2000) = 19h 58m 34.94s
Dec(J2000) = +51d 46' 52.5"
with an uncertainty of 2.1 arcseconds (radius, 90% containment). This
location is 68 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 in excess of the Galactic value (2.15 x
10^21 cm^-2, Willingale et al. 2013), with an excess column of 2.3
(+2.17/-1.95) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 104 seconds after the BAT trigger. There is a possible candidate
afterglow in the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 19:58:35.32 = 299.64717
DEC(J2000) = +51:46:53.0 = +51.78138
with a 90%-confidence error radius of about 0.6 arc sec. This position is 3.5
arc sec. from the center of the XRT error circle. The estimated magnitude is
18.71 with a 1-sigma error of about 0.15. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.15.
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/)
GCN Circular 27520
Subject
GRB 200410A: Ondrejov D50 afterglow confirmation
Date
2020-04-10T04:01:45Z (5 years ago)
From
Martin Jelinek at Astro.Inst-AVCR,Ondrejov <martin.jelinek@asu.cas.cz>
M. Jelinek, J. Strobl, R. Hudec, C. Polasek (ASU CAS Ondrejov)
report:
We observed the position of the GRB 200410A (Simpson et al., GCN 27518)
with the D50 telescope of the Astronomical Institute Ondrejov, near Prague,
Czech Republic, obtaining a series of 10s unfiltered images starting at
02:26:05.4UT, i.e. 55s post trigger.
The optical afterglow reported from UVOT (Simpson et al., GCN 27518) is
detected in the early single 20 s images.
We note the presence of two nearby stars which may confuse the observer
and/or complicate photometry. For this reason, we do not provide brightness
at this stage.
GCN Circular 27522
Subject
GRB 200410A: Enhanced Swift-XRT position
Date
2020-04-10T07:18:55Z (5 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1479 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 200410A, 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 = 299.64593, +51.78078 which is equivalent
to:
RA (J2000): 19h 58m 35.02s
Dec (J2000): +51d 46' 50.8"
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 27523
Subject
GRB 200410A: Swift-XRT refined Analysis
Date
2020-04-10T10:52:09Z (5 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
J. D. Gropp (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.A. Kennea (PSU),
A. Tohuvavohu (U. Toronto) and K.K. Simpson report on behalf of the
Swift-XRT team:
We have analysed 7.0 ks of XRT data for GRB 200410A (Simpson et al. GCN
Circ. 27518), from 86 s to 24.4 ks after the BAT trigger. The data
comprise 15 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 Goad et al.
(GCN Circ. 27522).
The light curve can be modelled with an initial power-law decay with an
index of alpha=4.2 (+2.6, -0.8), followed by a break at T+148 s to an
alpha of 0.58 (+/-0.04).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.99 (+0.18, -0.17). The
best-fitting absorption column is 2.7 (+0.7, -0.5) x 10^21 cm^-2,
consistent with the Galactic value of 2.2 x 10^21 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 (5.3 x
10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 2.7 (+0.7, -0.5) x 10^21 cm^-2
Galactic foreground: 2.2 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.99 (+0.18, -0.17)
If the light curve continues to decay with a power-law decay index of
0.58, the count rate at T+24 hours will be 0.037 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.4 x
10^-12 (1.9 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00965638.
This circular is an official product of the Swift-XRT team.
GCN Circular 27532
Subject
GRB 200410A: Swift/UVOT Detection
Date
2020-04-10T21:38:49Z (5 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL) and K. K. Simpson (PSU) report on behalf of the
Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 200410A
104 s after the BAT trigger (Simpson et al., GCN Circ. 27518).
A source consistent with the XRT position (Goad et al. GCN Circ. 27522)
is detected in the initial UVOT exposures.
The uvot position has been determined from the first white image to be
RA = 19:58:35.3
Dec = +51:46:53.0
or 299.64717 =51.78138 Deg (J2000) with an error estimate of 0.5".
There are two nearby stars visible at 4 and 6 arcsec.
Preliminary detections and 3-sigma upper limits 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 104 254 147 19.51 +/- 0.14
v 5051 6869 396 21.23 +/- 0.90
b 572 1519 98 19.61 +/- 0.32
u 317 567 246 20.39 +/- 0.37
w1 696 1294 57 >19.8
m2 671 1220 57 >20.0
w2 622 1270 57 >19.9
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.15 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 27578
Subject
GRB 200410A: Swift-BAT refined analysis
Date
2020-04-15T03:19:33Z (5 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
S. Laha (GSFC/UMBC), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
K. K. Simpson (PSU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry
downlink,
we report further analysis of BAT GRB 200410A (trigger #965638)
(Simpson et al., GCN Circ. 27518). The BAT ground-calculated position is
RA, Dec = 299.644, 51.745 deg which is
RA(J2000) = 19h 58m 34.6s
Dec(J2000) = +51d 44' 40.9"
with an uncertainty of 2.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 53%.
The mask-weighted light curve shows several weak pulses. The two main
pulses occur at ~T-20 s and ~T+2 s, respectively, followed by some weak
emission that lasts till ~T+50 s. T90 (15-350 keV) is 108.8 +- 40.7 sec
(estimated error including systematics).
The time-averaged spectrum from T-90.88 to T+50.62 sec is best fit by a
simple
power-law model. The power law index of the time-averaged spectrum is
1.41 +- 0.31. The fluence in the 15-150 keV band is 1.2 +- 0.2 x 10^-6
erg/cm2.
The 1-sec peak photon flux measured from T+1.43 sec in the 15-150 keV band
is 1.8 +- 0.3 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/965638/BA/
GCN Circular 27584
Subject
GRB 200410A: CALET Gamma-Ray Burst Monitor detection
Date
2020-04-15T12:20:30Z (5 years ago)
From
Valentin Pal'shin at AGU <val@phys.aoyama.ac.jp>
N. Cannady (GSFC/UMBC),
A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:
The Swift GRB 200410A (Simpson et al., GCN Circ. 27518, Laha et al.,
GCN Circ. 27578; https://gcn.gsfc.nasa.gov/other/200410A.gcn3)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 02:25:15.105 UTC
on 10 April 2020. The burst signal was seen by the SGM detector.
No real-time CGBM GCN notice was distributed about this trigger because
the real-time communication from the ISS was off (loss of signal).
The burst light curve shows a weak pulse which starts at T-3.9 sec, peaks
at T-1.0 sec and ends at T+2.4 sec. The T90 and T50 durations measured by
the SGM data are 5.5 +- 2.2 sec and 2 +- 2 sec (40-1000 keV), respectively.
The ground processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1270520355/
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at the Waseda University.
GCN Circular 27603
Subject
GRB 200410A: Optical upper limit
Date
2020-04-18T07:14:21Z (5 years ago)
From
Amit Kumar at ARIES, India <amitkundu515@gmail.com>
A. Kumar (ARIES), A. Ghosh (ARIES), Dimple (ARIES), A. Aryan (ARIES), R.
Gupta (ARIES), S. B. Pandey (ARIES), and K. Misra (ARIES) report:
We observed the field of Swift GRB 200410A (Simpson et al., GCN Circ.
27518, Gropp et al., GCN 27523, Kuin et al., GCN 27532, Pizzuto et al., GCN
27552, Laha et al., GCN Circ. 27578, Valentin et al., GCN 27584) with the
1.3m Devsthal Fast Optical Telescope (DFOT) at Aryabhatta Research
Institute of Observational Sciences (ARIES), Nainital
(India), from 2020-04-10 UT 21:34:29 to 2020-04-10 UT 23:31:07
(corresponding to
19.15 to 21.09 hours from the GRB trigger time). We observed 12 frames
each of 300 seconds in Bessel R filter and a series of 11x300 seconds
exposures in
Bessel I filter. As mentioned by Jelinek et al., 27520, at the position of
the optical afterglow of GRB 200410A there are two nearby stars, so to do
the photometry we observed 300 seconds frame in Bessel R and I filter on
2020-04-15 UT 21:26:22 (5.79 days since burst) to do the template
subtraction. Template subtraction was done using the IRAF (
http://iraf.noao.edu/).
After the template subtraction, we do not find any new optical source
within the Swift XRT enhanced error circle in any individual as well as the
stacked frame.
The 3-sigma upper limits are as follows:
T_start-T0 (days) Start Date (UTC) End Date (UTC)
Filter 3-sigma upper limit (mag)
---------------------------------------------------------------------------------------------------------------
19.15 2020-04-10 21:34:29 2020-04-10 22:30:06
R >22.2
20.18 2020-04-10 22:35:46 2020-04-10 23:31:07
I >22.4
Photometry is done based on the USNO-B1.0 catalog. The quoted magnitudes
are not corrected for Galactic extinction.
[GCN OPS NOTE(18apr20): The author-constructed header was removed. The header
is supplied by the GCN processing system.]
GCN Circular 27621
Subject
GRB 200410A: Liverpool Telescope First Hour Observations
Date
2020-04-22T11:40:04Z (5 years ago)
From
Iain Steele at Liverpool/JMU <i.a.steele@ljmu.ac.uk>
I.A. Steele, M. Shrestha, S. Kobayashi (Liverpool JMU), C. Mundell (Univ. Bath), A. Gomboc (Univ. Nova Gorica) report on behalf of a wider collaboration:
We observed the field of Swift GRB 200410A (GCN 27518) with the 2.0m Liverpool Telescope, La Palma on 2020 Apr 10 starting at 02:28:38 UT using the IOO optical camera for a period of ~1 hour in the r��� and I��� bands. The target was well resolved from the two nearby stars. Data was calibrated with respect to APASS secondary standard stars in the images.
We confirm the optical counterpart reported by Swift UVOT and Ondrejov (GCN 27520).
At T=155 seconds after the BAT trigger time, we measure r��� = 18.2.
Both the r��� and i��� band light curves subsequently show a power law decay in flux vs time with alpha = 0.7 over the first hour.
________________________________
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