GRB 200324A
GCN Circular 27428
Subject
GRB 200324A: Swift detection of a burst
Date
2020-03-24T16:57:02Z (5 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
S. Dichiara (NASA/GSFC/UMCP), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), M. G. Bernardini (INAF-OAB),
P. D'Avanzo (INAF-OAB), V. D'Elia (SSDC), J.D. Gropp (PSU),
J. A. Kennea (PSU), N. J. Klingler (PSU), S. Laha (GSFC/UMBC/CRESST),
F. E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB),
K. L. Page (U Leicester), D. M. Palmer (LANL), T. Sbarrato (INAF-OAB),
B. Sbarufatti (PSU) and T. N. Ukwatta (LANL) report on behalf of the
Neil Gehrels Swift Observatory Team:
At 16:39:07 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 200324A (trigger=963260). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 222.685, +35.968 which is
RA(J2000) = 14h 50m 44s
Dec(J2000) = +35d 58' 06"
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 60 sec. The peak count rate
was ~1200 counts/sec (15-350 keV), at ~2 sec after the trigger.
The XRT began observing the field at 16:42:11.8 UT, 183.9 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source located at RA, Dec 222.67198,
35.94100 which is equivalent to:
RA(J2000) = 14h 50m 41.28s
Dec(J2000) = +35d 56' 27.6"
with an uncertainty of 3.5 arcseconds (radius, 90% containment). This
location is 104 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 (1.07 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 3.9
(+2.21/-1.93) x 10^21 cm^-2 (90% confidence).
The initial flux in the 2.5 s image was 1.27e-09 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 194 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
0.01.
This source lies within the current (Sector 23) field-of-view of TESS camera 2.
Burst Advocate for this burst is S. Dichiara (dichiara AT umd.edu).
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 27429
Subject
GRB 200324A:MITSuME Akeno optical upper limits
Date
2020-03-24T17:45:42Z (5 years ago)
From
Ryohei Hosokawa at Tokyo Institute of Technology <hosokawa@hp.phys.titech.ac.jp>
R. Hosokawa,R. Adachi, K. L. Murata, M. Oeda, K. Shiraishi, K. Iida,
M. Niwano, F. Ogawa, S. Toma, N. Nakamura, Y. Yatsu, and N.
Kawai(TokyoTech) report on behalf of the MITSuME collaboration:
We searched for the optical counterpart of GRB 200324A (S. Dichiara et
al., GCN Circular #27428) 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 16:42:46 UT. We did not find any new point
sources within the Swift XRT circle (S. Dichiara et al., GCN Circular
#27428) in all three bands.
We obtained the 5-sigma limits as follows.
T0+[sec] MID-UT T-EXP[sec] 5-sigma limits
------------------------------------------------------------------------------------------------
219 16:46:39 420 g'>18.9,Rc>18.6,Ic>17.6
------------------------------------------------------------------------------------------------
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 27430
Subject
GRB 200324A: Enhanced Swift-XRT position
Date
2020-03-24T19:14:23Z (5 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 1203 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 200324A, 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 = 222.67373, +35.94173 which is equivalent
to:
RA (J2000): 14h 50m 41.70s
Dec (J2000): +35d 56' 30.2"
with an uncertainty of 1.7 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 27431
Subject
GRB 200324A: Tautenburg observations
Date
2020-03-24T22:50:57Z (5 years ago)
From
Sylvio Klose at TLS Tautenburg <klose@tls-tautenburg.de>
B. Stecklum, S. Klose, A. Nicuesa Guelbenzu, S. Melnikov, and F. Ludwig (all
Tautenburg) report:
We observed the field of GRB 200324A (Dichiara et al., GCN 27428) with the
Tautenburg 1.34m Schmidt telescope equipped with the TAUKAM 6k x 6k CCD camera
and the wide V-band filter (VB). The transmission curve of this filter closely
follows the Gaia GBP filter. Observations started at 20:08:15 UT and consisted
of 5x5 min exposures.
Inside the enhanced XRT error circle (Beardmore et al., GCN 27430) we do not
find any optical transient. Based on Gaia DR2 stars in the field, we provide an
upper limit of VB > 22.0 mag (Vega system; 3.5 hr after the burst). We note
that only ~5 arcsec north of the center of the XRT error circle lies the faint
SDSS-DR8 source J145041.56+355635.6, possibly the GRB host galaxy.
GCN Circular 27432
Subject
GRB 200324A: NOT optical upper limit
Date
2020-03-24T23:47:48Z (5 years ago)
From
Daniele B Malesani at DTU Space <malesani@space.dtu.dk>
Johan P. U. Fynbo (DAWN/NBI), Daniele B. Malesani (DTU Space), Abel de
Burgos Sierra (NOT), Thomas Augusteijn (NOT), report on behalf of a
larger collaboration:
On 2020 March 24.97 UT (6 hr 39 min after the trigger) we observed the
field of GRB 200324A (Dichiara et al., GCN 27428; Beardmore et al., GCN
27430) with the Nordic Optical Telescope equipped with ALFOSC in the
SDSS r filter, for a total integration time of 300 s. We find no
evidence for afterglow emission above a 3-sigma limit of about 23 mag.
Our result is consistent with the non-detection by Stecklum et al. (GCN
27431).
GCN Circular 27433
Subject
GRB 200324A: Konkoly Obs. optical upper limit
Date
2020-03-25T03:08:41Z (5 years ago)
From
Jozsef Vinko at Konkoly Observatory <vinko@konkoly.hu>
J. Vinko (Konkoly/ELTE/U Szeged), A. Ordasi (Konkoly), L. Kriskovics (Konkoly), R. Szakats (Konkoly) and A. Pal (Konkoly) report on behalf of the "Transient Astrophyical Objects" project:
We observed the field of GRB 200324A (Dichiara et al. GCN 27428; Beardmore et al., GCN
27430; Stecklum et al. GCN 27431; Fynbo et al. GCN 27432) with the 0.8m RC80 robotic telescope
at Piszkesteto Mountain Station of Konkoly Observatory through SDSS r' filter on 2020 March 24.88 UT
(MJD 58932.885, 4h 36m after the trigger). The total exposure time was 1800 s. The frames were tied
to PS1-photometry of local stellar sources. No optical counterpart for the GRB has been detected
above the 3-sigma upper limit of 21.7 AB-mag, which is consistent with other reports of non-detection.
GCN Circular 27435
Subject
GRB 200324A: Swift-XRT refined Analysis
Date
2020-03-25T05:02:10Z (5 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), J.A. Kennea (PSU), A.
Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), P.A. Evans (U.
Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.
Melandri (INAF-OAB) and S. Dichiara report on behalf of the Swift-XRT
team:
We have analysed 6.2 ks of XRT data for GRB 200324A (Dichiara et al.
GCN Circ. 27428), from 190 s to 35.9 ks after the BAT trigger. The
data comprise 163 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Beardmore et al. (GCN Circ. 27430).
The light curve can be modelled with an initial power-law decay with an
index of alpha=3.61 (+0.29, -0.25), followed by a break at T+434 s to
an alpha of 1.03 (+/-0.07).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.48 (+0.13, -0.11). The
best-fitting absorption column is 1.49 (+0.28, -0.26) x 10^21 cm^-2,
in excess of the Galactic value of 1.1 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.92 (+0.18, -0.17)
and a best-fitting absorption column of 2.7 (+/-0.7) x 10^21 cm^-2. The
counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 3.8 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) x 10^21 cm^-2
Galactic foreground: 1.1 x 10^20 cm^-2
Excess significance: 6.3 sigma
Photon index: 1.92 (+0.18, -0.17)
If the light curve continues to decay with a power-law decay index of
1.03, the count rate at T+24 hours will be 8.1 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.1 x
10^-13 (4.4 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/00963260.
This circular is an official product of the Swift-XRT team.
GCN Circular 27436
Subject
GRB 200324A: LCO Optical Upper Limit
Date
2020-03-25T07:21:16Z (5 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 200324A (Dichiara et al., GCN 27428) with the LCO 1-m Sinistro instrument at the McDonald Observatory, USA site, on March 25, from 6:06 to 6:46 UT (corresponding to 13.28 to 13.95 hours from the GRB trigger time) with the Bessel I and R filters.
We performed a series of 5x240s exposures in I and R. We do not detect any sources in the individual frames (nor in stacked images) in the Swift enhanced error region (Beardmore et al., GCN 27430), consistent with other optical non-detections. Using the USNO-B.1 catalog as reference, we obtain the following 3-sigma upper limits:
R > 24.21
I > 22.56
R.S. is funded by NSF AST grant #1831682
GCN Circular 27439
Subject
GRB 200324A: Swift/UVOT Upper Limits
Date
2020-03-25T12:48:41Z (5 years ago)
From
Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk>
A. A. Breeveld (UCL-MSSL) and S. Dichiara (NASA/GSFC/UMCP)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 200324A 215 s after the BAT trigger
(Dichiara et al., GCN Circ. 27428).
No optical afterglow consistent with the XRT position (Beardmore et al. GCN Circ. 27430)
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 215 365 147 >21.0
u_FC 374 624 246 >20.6
white 215 1376 373 >21.7
v 704 1427 78 >18.9
b 630 1527 97 >19.8
u 374 1327 304 >20.2
w1 754 1477 78 >19.1
w2 1381 1401 19 >19.1
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of
E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998).
GCN Circular 27440
Subject
GRB 200324A:: TSHAO optical upper limit
Date
2020-03-25T14:19:13Z (5 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), I. Reva (FAPHI), A. Pozanenko (IKI), M. Krugov (FAPHI),
E. Mazaeva (IKI), A. Volnova (IKI) report on behalf of IKI-GRB-FuN:
We observed the field of GRB 200324A: (Dichiara et al. GCN 27428) with
Zeiss-1000 1-m telescope of Tien Shan Astronomical Observatory starting
on Mar. 24 (UT) 17:35:57. We found no one object within enhanced
Swift-XRT position (Beardmore et al., GCN 27430). Preliminary
photometry of the field is following.
Date UT start t-T0 Filter Exp. OT Err. UL(3 sigma)
(mid, days) (s)
2020-03-24 17:35:57 0.0638 R 4200 n/d n/d 21.3
The photometry is based on nearby SDSS-DR12 stars.
RA DEC R(Lupton transformation)
222.719432 35.941281 17.353
222.755165 35.913578 16.314
222.698647 35.902796 16.214
222.827959 35.919356 15.822
GCN Circular 27443
Subject
GRB 200324A, Swift-BAT refined analysis
Date
2020-03-25T21:13:14Z (5 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), S. Dichiara (NASA/GSFC/UMCP),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU) (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 200324A (trigger #963260)
(Dichiara et al., GCN Circ. 27428). The BAT ground-calculated position is
RA, Dec = 222.682, 35.931 deg which is
RA(J2000) = 14h 50m 43.7s
Dec(J2000) = +35d 55' 51.0"
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.
The mask-weighted light curve shows a weak pulse that starts
at ~T-40 s, peaks at ~T0, and lasts until >~T+80 s. The burst was
temporarily out of the BAT FOV from T+100.39 s to T+119.39 s.
There might be additional burst emission during this period.
Due to this data gap, the standard data analysis pipeline
is unable to estimate an accurate T90.
The time-averaged spectrum from T-38.1 to T+100.4 sec (before
the burst went out of the BAT FOV) is best fit by a simple power-law model.
The power law index of the time-averaged spectrum is 1.72 +- 0.15.
The fluence in the 15-150 keV band is 2.3 +- 0.2 x 10^-6 erg/cm2. The 1-sec
peak photon flux measured from T+0.07 sec in the 15-150 keV band
is 0.7 +- 0.2 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/963260/BA/
GCN Circular 27445
Subject
GRB 200324A: AROMA-N Optical Observation
Date
2020-03-26T06:44:11Z (5 years ago)
From
Takanori Sakamoto at AGU <tsakamoto@phys.aoyama.ac.jp>
M. Nakamura, T. Sakamoto (AGU)
We observed the field of GRB 200324A detected by Swift
(Dichiara et al., GCN Circ. 27428) with the 14-inch AGU Robotic
Optical Monitor for Astrophysical object - Narrow (AROMA-N)
located at the Sagamihara campus of Aoyama Gakuin University.
22 images of 60 sec, 120 sec, 180 sec and 300 sec exposures
were taken in the R filter starting from March 24 16:42:55 (UT)
about 228 seconds after the trigger and stopped on March 24 19:06:11 (UT).
We do not detect the optical afterglow both in the individual
images and the stacked image. The estimated five sigma upper limit
of the combined image (total exposure of 3240 sec) is ~17.6 mag
using the USNO-B1 catalog.