GRB 210419C
GCN Circular 29834
Subject
GRB 210419C: Swift detection of a burst
Date
2021-04-20T00:45:40Z (4 years ago)
From
Michael Moss at George Washington U <mikejmoss3@gmail.com>
M. J. Moss (GWU), V. D'Elia (SSDC & INAF-OAR), C. Gronwall (PSU),
J.D. Gropp (PSU), J. A. Kennea (PSU), N. J. Klingler (PSU),
N. P. M. Kuin (UCL-MSSL), S. Laha (GSFC/UMBC/CRESST),
A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), M. H. Siegel (PSU)
and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels
Swift Observatory Team:
At 23:27:49 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 210419C (trigger=1044236). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 212.968, 35.999 which is
RA(J2000) = 14h 11m 52s
Dec(J2000) = +35d 59' 56"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). Currently, we only have limited BAT light curve data.
The available light curve from ~T+110 s to ~T+400 s does
not show any significant structure.
Due to lack of data, we do not have an accurate XRT position. However our current
best estimate for the GRB position is RA/Dec(J2000) = 212.96009,
+36.0096, which is equivalent to:
RA(J2000): 14h 11m 50.4s
Dec(J2000): 36d 00m 34.6s
Uncertainty of this position is unclear. We await ground
processed data to report an accurate position for this GRB.
UVOT took a finding chart exposure of ���95��� seconds with the ���U��� filter
starting��� around 340 ���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
0.0���1���.
Burst Advocate for this burst is M. J. Moss (mikejmoss3 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 29839
Subject
GRB 210419C: Enhanced Swift-XRT position
Date
2021-04-20T14:59:26Z (4 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 2102 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 210419C, 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 = 212.96251, +36.00741 which is equivalent
to:
RA (J2000): 14h 11m 51.00s
Dec (J2000): +36d 00' 26.7"
with an uncertainty of 2.4 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 29840
Subject
GRB 210419C: KAIT Optical Upper Limit
Date
2021-04-20T15:17:16Z (4 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 Swift GRB 210419C (Moss et al.,
GCN 29834) starting at 6.87 hours after the burst. A total of
30x60s images were obtained in the clear (roughly R) filters.
We do not detect any new source within the enhanced XRT error circle
(Beardmore et al., GCN 29839) in the co-add images, down to a limiting
magnitude of ~21.5 mag calibrated to the PS1 catalog.
GCN Circular 29842
Subject
GRB 210419C: Montarrenti Observatory Upper Limit
Date
2021-04-20T16:21:43Z (4 years ago)
From
Simone Leonini at Monarrenti Obs <s.leonini@iol.it>
Simone Leonini, M. Conti, P. Rosi and L.M. Tinjaca Ramirez (Montarrenti Observatory, Siena, Italy) report:
We observed the field of GRB210419C (Swift trigger 1044236, M.J. Moss et al., GCN Circ. 29834) with the automatic 0.53m RC telescope + U47 detector at Montarrenti Observatory (Siena, Italy, IAU code C88).
The observations were started under variable weather conditions at 2021-04-20 01:48:32 UT (3.780s after notice) stacking 12x30s clear filter CCD exposures.
We have not found optical transient within the error-box of the enhanced Swift-XRT position (RA 14h 11m 51.00s, Dec +36d 00m 26.7s - J2000).
Mag. upper limit R = 20.40+/-0.15
Magnitudes were obtained using Astrometrica software using USNO-B1 catalogue and are not corrected for galactic extinction.
Our non-detection is consistent with the limits reported by MASTER-Net (Lipunov et al, GCNC 29836) and KAIT (W.K. Zheng and A.V. Filippenko, GCNC 29840).
GCN Circular 29843
Subject
GRB 210419C: RATIR Optical and NIR Upper Limits
Date
2021-04-20T16:34:17Z (4 years ago)
From
Nat Butler at Az State U <natbutler@asu.edu>
Nat Butler (ASU), Alan M. Watson (UNAM), 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 210419C (Moss, et al., GCN 29834) with the
Reionization and Transients Infrared Camera (RATIR) on the 1.5m Harold
Johnson Telescope at the Observatorio Astron��mico Nacional on Sierra San
Pedro M��rtir from 2021/04 20.14 to 2021/04 20.50 UTC (2.58 to 11.15 hours
after the BAT trigger), obtaining a total of 4.53 hours exposure in the r
and i bands and 1.89 hours exposure in the Z, Y, J, and H bands.
We do not detect any sources within the enhanced XRT error region
(Beardmore, et al. GCN 29839). In comparison with the SDSS DR9 and 2MASS
catalogs, we obtain the following upper limits (3-sigma):
r > 23.60
i > 23.53
Z > 22.31
Y > 20.10
J > 22.21
H > 21.87
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 29856
Subject
GRB 210419C: Swift-BAT refined analysis
Date
2021-04-21T03:33:02Z (4 years ago)
From
Sibasish Laha at GSFC <sibasish.laha@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),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):
Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 210419C (trigger #1044236)
(Moss et al., GCN Circ. 29834). The BAT ground-calculated position is
RA, Dec = 212.969, 36.011 deg which is
RA(J2000) = 14h 11m 52.6s
Dec(J2000) = +36d 00' 40.5"
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 72%.
The BAT light curve showed a complex structure with a duration of about ~70 sec.
T90 (15-350 keV) is 73.00 +- 16.40 sec (estimated error including systematics).
The time-averaged spectrum from T+16.00 to T+102.00 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
2.50 +- 0.27. The fluence in the 15-150 keV band is 8.1 +- 1.2 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T+48.00 sec in the 15-150 keV band
is 0.8 +- 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/1044236/BA/
GCN Circular 29859
Subject
GRB 210419C: MITSuME Akeno optical upper limits
Date
2021-04-21T09:18:53Z (4 years ago)
From
Katsuhiro L. Murata at Nagoya U <murata@u.phys.nagoya-u.ac.jp>
K. L. Murata, R. Hosokawa, M. Niwano, N. Ito, H. Takamatsu, Y. Yatsu, and
N.Kawai (TokyoTech) report on behalf of the MITSuME collaboration:
We observed the field of GRB 210419C (M. J. Moss et al. GCN Circular
#29834, A.P. Beardmore et al. GCN Circular #29839, WeiKang Zheng and Alexei
V. Filippenko report on et al. GCN Circular #29840, Simone Leonini et al.
GCN Circular #29842, Nat Butler et al. GCN Circular #29843, T. Sakamoto et
al. GCN Circular #29856) 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 with a series of 60 sec exposures started
at 2021-04-20 10:40:08 UT (11.2 hours after the Swift BAT trigger). We
stacked the images with good conditions. We did not detect any sources
within the enhanced XRT error region (A.P. Beardmore et al. GCN Circular
#29839) in all three bands. We obtained the 5-sigma limits of the stacked
images as follows.
T0+[hour] MID-UT T-EXP[sec] 5-sigma limits
------------------------------------------------------------------------------------------------
11.6 11:38 3000 g'>19.6, Rc>19.9, Ic>19.3
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used the PS1 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. 2021, PASJ, Vol.73, Issue 1, Pages 4-24;
https://github.com/MNiwano/Eclaire).
GCN Circular 29868
Subject
GRB 210419C: Swift/UVOT Upper Limits
Date
2021-04-21T16:30:59Z (4 years ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
M. H. Siegel (PSU) and M. J. Moss (GWU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 210419C
156 s after the BAT trigger (Moss et al., GCN Circ. 29834).
No optical afterglow consistent with the XRT position
(Beardmore et al. GCN Circ. 29839)
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 156 305 147 >20.83
white 6954 17801 254 >21.14
v 11428 28719 155 >19.22
b 6749 17713 1081 >21.37
u 313 408 93 >19.55
u 6544 22974 258 >20.20
UVW1 6339 22905 1082 >20.49
UVM2 6134 6334 196 >19.21
UVW2 10522 28626 1771 >20.84
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.010 in the direction of the burst
(Schlegel et al. 1998).