GRB 130327A
GCN Circular 14331
Subject
GRB 130327A: Swift detection of a burst
Date
2013-03-27T02:09:19Z (12 years ago)
From
Jamie A. Kennea at PSU/Swift-XRT <kennea@swift.psu.edu>
T. N. Ukwatta (MSU), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), N. Gehrels (NASA/GSFC),
J. A. Kennea (PSU), V. Mangano (INAF-IASFPA),
C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC),
A. Maselli (INAF-IASFPA), D. M. Palmer (LANL), M. H. Siegel (PSU) and
C. A. Swenson (PSU) report on behalf of the Swift Team:
At 01:47:34 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 130327A (trigger=552063). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 91.992, +55.730 which is
RA(J2000) = 06h 07m 58s
Dec(J2000) = +55d 43' 49"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows a weak single peak
with a duration of about 10 sec. The peak count rate
was ~900 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 01:49:55.0 UT, 141.0 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 92.0387, 55.7143 which
is equivalent to:
RA(J2000) = 06h 08m 09.29s
Dec(J2000) = +55d 42' 51.5"
with an uncertainty of 2.7 arcseconds (radius, 90% containment). This
location is 110 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
http://www.swift.ac.uk/sper. We cannot determine whether the source is
fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 1.31
x 10^21 cm^-2 (Kalberla et al. 2005).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 104 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 none of
the XRT error circle. 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 0.13.
Burst Advocate for this burst is T. N. Ukwatta (tilan.ukwatta 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/too.html.)
GCN Circular 14333
Subject
GRB 130327A: PAIRITEL NIR Afterglow Candidate
Date
2013-03-27T03:39:24Z (12 years ago)
From
Adam Morgan at U.C. Berkeley <qmorgan@gmail.com>
A. N. Morgan (UC Berkeley) reports:
We observed the field of GRB 130327A (Ukwatta et al., GCN 14331) with the
1.3m PAIRITEL located at Mt. Hopkins, Arizona. Observations began at
2013-Mar-27 02h21m22s UT, ~33.8 minutes after the Swift trigger. In
mosaics (effective exposure time of ~25 m) taken simultaneously in the J,
H, and Ks filters, we marginally detect a source in the J band within the
XRT error circle (Ukwatta et al., GCN 14331). Given the minor significance
of the detection in only a single filter, deeper observations are
encouraged to confirm if this possible source is indeed the afterglow of
GRB 130327A.
post burst
t_mid (hr) exp.(hr) filt Mag
0.91 0.42 J 17.8 +/- 0.4
0.91 0.42 H > 17.1
0.91 0.42 Ks > 15.7
All magnitudes are given in the Vega system, calibrated to 2MASS. No
correction for Galactic extinction has been made to the above reported
values. Observations are ongoing.
GCN Circular 14334
Subject
GRB 130327A: RATIR Optical and NIR Observations
Date
2013-03-27T04:56:14Z (12 years ago)
Edited On
2024-11-07T18:58:54Z (7 months ago)
From
Nat Butler at UC berkeley <natxbutler@gmail.com>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC),
William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB),
Ori Fox (UCB) J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino
Cucchiara (UCSC), Eleonora Troja (GSFC), Enrico Ramirez-Ruiz (UCSC),
José A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González
(UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC), and Harvey
Moseley (GSFC) report:
We observed the field of GRB 130327A (Ukwatta, et al., GCN 14331) with
the Reionization and Transients Infrared Camera (RATIR; www.ratir.org)
on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico
Nacional on Sierra San Pedro Mártir from 2013/03 27.12 to 2013/03
27.17 UTC (1.16 to 2.17 hours after the BAT trigger), obtaining a
total of 0.82 hours exposures in the r' and i' bands and 0.35 hours of
exposure in the Z, Y, J, and H bands.
We detect one uncatalogued source within the XRT error region (GCN
14331), at a position RA , DEC: = 92.03875, 55.71504 (+/-0.5 ",
J2000). This is 2.7" from the center of the XRT error circle. In
comparison with USNO-B1 and 2MASS, we derive the following detections
and upper limit (3-sigma) in the AB magnitude system:
r' 21.22 +/- 0.10
i' 21.17 +/- 0.09
Z 20.09 +/- 0.14
Y 19.98 +/- 0.17
J 19.98 +/- 0.23
H > 20.08
We also detect a second uncatalogued source just outside the XRT error
circle (3.9" from the center) at RA , DEC: 92.03822, 55.71326 (+/-0.5
", J2000):
r' 21.61 +/- 0.14
i' 20.36 +/- 0.05
Z 19.15 +/- 0.06
Y 18.72 +/- 0.06
J 18.70 +/- 0.07
H 18.53 +/- 0.09
We note that this second source has a brightness consistent with the
earlier PAIRITEL measurement (Morgan; GCN 14333).
We thank the staff of the Observatorio Astronómico Nacional in San
Pedro Mártir. Further observations are planned.
GCN Circular 14335
Subject
GRB 130327A: Enhanced Swift-XRT position
Date
2013-03-27T07:49:55Z (12 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1239 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 130327A, 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 = 92.03858, +55.71475 which is equivalent
to:
RA (J2000): 06h 08m 9.26s
Dec (J2000): +55d 42' 53.1"
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 14337
Subject
GRB 130327A: ISON-NM optical upper limit
Date
2013-03-27T09:59:23Z (12 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
L. Elenin (KIAM), A. Volnova (SAI MSU), I. Molotov (KIAM), A. Pozanenko
(IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of the Swift GRB 130327A (Ukwatta, et al., GCN
14331) with 0.45-m telescope of ISON-NM observatory on Mar. 27,
between (UT) 02:44:04 - 03:27:54. We took several unfiltered images of
30 s exposures. Within enhanced XRT afterglow position (Osborne et al.,
GCN 14335) we do not detect any new object. We marginally (S/N~2.5, R~
20.3) detected "second uncatalogued source" (Morgan et al., GCN 14333;
Butler et al., GCN 14334) at RA , DEC (J2000): 06 08 09.06 +55 42 48.5.
A photometry of combined image is based on the USNO-B1.0 (R2)
nearby stars
Start, T0+, Exposure, OT, UL (3 sigma)
(UT) mid, d (s)
02:44:04 0.0546 60x30 n/d 20.0
GCN Circular 14339
Subject
GRB 130327A: Swift/UVOT Upper Limits
Date
2013-03-27T14:22:35Z (12 years ago)
From
Craig Swenson at PSU/Swift <cswenson@astro.psu.edu>
C. A. Swenson (PSU) and T. N. Ukwatta (MSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 130327A
104 s after the BAT trigger (Ukwatta et al., GCN Circ. 14331).
No optical afterglow consistent with the XRT position
(Osborne et al. GCN Circ. 14335)
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 104 254 147 >21.2
u_FC 317 567 246 >20.0
white 104 6491 727 >21.8
v 646 6877 428 >19.8
b 572 6286 432 >20.7
u 317 6081 659 >20.4
w1 695 12014 1111 >21.6
m2 671 11107 1141 >21.0
w2 622 6696 452 >21.9
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.13 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 14340
Subject
GRB 130327A: Weihai optical obsevations
Date
2013-03-27T17:51:32Z (12 years ago)
From
Dong Xu at DARK/NBI <dong.dark@gmail.com>
D. Xu (DARK/NBI), C. Cao, S. M. Hu (SDU) report:
We observed the field of GRB 130327A (Ukwatta et al., GCN 14331) using
the 1m telescope located in Weihai, Shandong Province, China.
Observations started at 11:27:02 UT on 2013-03-27 (i.e, 9.658 hr after
the burst) in a seeing of ~2.8", and 10x360s I-band images were
obtained with a mean time of 10.158 hr post-burst.
Within the enhanced XRT error circle (Osborne et al., GCN 14335), no
credible source is detected in the stacked I-band image, down to a
limit of R>20.2 mag, calibrated with the USNO B1 catalogue.
A source, with R~19.2 mag and somehow extended along NW-SE, is
detected at the position of the "second uncatalogued source" reported
by Butler et al. (GCN 14334), and confirmed in Elenin et al. (GCN
14337). This source might be the one in Morgan (GCN 14333). Since it
is 5.5" away from the center of the enhanced XRT error circle (radius:
1.9") and it's getting brightening significantly, this source is
unlikely related to the afterglow of the burst.
We thank Dayong Ren for carrying out thee observations.
GCN Circular 14341
Subject
GRB 130327A: Swift-XRT refined Analysis
Date
2013-03-27T19:09:04Z (12 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
C. Pagani (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A.
Maselli (INAF-IASFPA), D.N. Burrows (PSU), J.A. Kennea (PSU), M.C.
Stroh (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester)
and T.N. Ukwatta report on behalf of the Swift-XRT team:
We have analysed 10 ks of XRT data for GRB 130327A (Ukwatta et al. GCN
Circ. 14331), from 83 s to 45.1 ks after the BAT trigger. The data
comprise 902 s in Windowed Timing (WT) mode (the first 9 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 Osborne et
al. (GCN. Circ 14335).
The light curve can be modelled with an initial power-law decay with an
index of alpha=4.3 (+0.5, -0.4), followed by a break at T+348 s to an
alpha of 0.22 (+0.07, -0.08).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.28 (+0.29, -0.13). The
best-fitting absorption column is consistent with the Galactic value
of 1.3 x 10^21 cm^-2 (Kalberla et al. 2005). The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum is 3.2 x 10^-11 (4.1 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 0 (+3.7, -0) x 10^20 cm^-2
Galactic foreground: 1.3 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index: 2.28 (+0.29, -0.13)
If the light curve continues to decay with a power-law decay index of
0.22, the count rate at T+24 hours will be 0.012 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.7 x
10^-13 (4.8 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/00552063.
This circular is an official product of the Swift-XRT team.
GCN Circular 14342
Subject
GRB 130327A: Gemini Observations
Date
2013-03-27T21:20:55Z (12 years ago)
From
Antonino Cucchiara at UCSC/UCO Lick <acucchia@ucolick.org>
A. Cucchiara (UCSC/UCO Lick Observatory) and S. B. Cenko
(UC Berkeley) report on behalf of a large collaboration:
"On March 27.25 UT we observed the field of GRB 130327A
(Ukwatta et al., GCN 14331) with the Gemini-North telescope
equipped with the GMOS camera.
We obtained a 4 minutes i' band image of the field:
the two sources identified by Butler et al. (GCN 14334)
are both detected.
The southern source (#1) is located at
RA: 06:08:09.12 (J2000)
Dec: +55:42:47.98 (J2000)
The northern source (#2) is located inside the XRT revised
error circle (Osborne et al. GCN 14335) at:
RA: 06:08:09.25 (J2000)
Dec: +55:42:54.39 (J2000)
Using several nearby USNO-B1 stars we estimated i' = 19.81
+- 0.02, (source #1), and i' = 21.75 +- 0.06 (source #2),
which is 0.43 mag fainter than the RATIR observations.
We also obtained a 2x900s spectra of these two sources under cloudy
conditions, covering the 6000-10000A wavelength range: source #1
presents several stellar features, while source #2 presents a noisy
continuum, but no clear absorption features are identified.
If we assume that source #2 is indeed GRB 130327A afterglow, we can
place an upper limit on the GRB redshift of z < 3.9, based on the
absence of a Lyman-break features.
Our acquisition image can be found here:
https://www.dropbox.com/s/ygvcdykmpow6gq5/sources.jpeg
We thank the Gemini staff for performing this observations,
in particular Andre'-Nicolas Chene' "
GCN Circular 14343
Subject
GRB 130327A: Swift-BAT refined analysis
Date
2013-03-27T21:54:49Z (12 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
A. Y. Lien (NASA/GSFC/ORAU), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS),
M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 130327A (trigger #552063)
(Ukwatta, et al., GCN Circ. 14140). The BAT ground-calculated position is
RA, Dec = 91.984, 55.732 deg, which is
RA(J2000) = 06h 07m 56.2s
Dec(J2000) = +55d 43' 56.2"
with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 61%.
The mask-weighted lightcurve shows a single peak starting at ~T-5 sec,
peaking at ~T+1 sec, and ending at ~T+8 sec. T90 (15-350 keV) is
9.0 +- 2.8 sec (estimated error including systematics).
The time-averaged spectrum from T-4.38 to T+5.62 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
2.26 +- 0.36. The fluence in the 15-150 keV band is 2.3 +- 0.5 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.62 sec in the 15-150 keV band
is 0.9 +- 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/552063/BA/
GCN Circular 14352
Subject
GRB 130327A: RATIR Optical/NIR afterglow confirmation
Date
2013-03-29T00:21:46Z (12 years ago)
Edited On
2024-11-07T19:48:31Z (7 months ago)
From
Antonino Cucchiara at UCSC/UCO Lick <acucchia@ucolick.org>
Edited By
Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
Antonino Cucchiara (UCSC), Nat Butler (ASU), Alan M. Watson (UNAM),
Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM),
Chris Klein (UCB), Ori Fox (UCB) J. Xavier Prochaska (UCSC), Josh Bloom
(UCB), Eleonora Troja (GSFC), Enrico Ramirez-Ruiz (UCSC), José A. de Diego
(UNAM), Leonid Georgiev (UNAM), Jesús González (UNAM), Carlos Román-Zúñiga
(UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
We reobserved the field of GRB 130327A (Ukwatta et al., GCN 14331,
and Osborne et al., GCN 14335) with the Reionization and Transients
Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson
Telescope at the Observatorio Astronómico Nacional on Sierra San Pedro
Mártir from 2013/03 28.13 to 2013/03 28.14 UTC (25.24 to 25.64 hours
after the BAT trigger), obtaining a total of 0.33 hours exposure in the
r' and i' bands and 0.14 hours of exposure in the Z, Y, J, and H bands.
The source identified in our previous RATIR observations within the refined XRT
error circle (Butler et al. GCN 14334), and detected by Gemini (source #2
in GCN 14342) has faded below our detection limit. We report the following
3-sigma limits in the AB magnitude system:
r' > 22.67
i' > 22.46
Z > 20.83
Y > 20.47
J > 20.07
H > 19.99
This fading is consistent with the fading reported by Cucchiara et al.
(GCN 14342). Based on these observations we confirm that this was the
optical/NIR afterglow of GRB 130327A.
The second source identified outside the refined XRT error circle in the
first RATIR observation and detected also by Gemini (as source #1 in GCN 14342)
has not faded. Therefore it is unrelated to GRB 130327A.
These magnitudes are not corrected for Galactic extinction in the direction
of the GRB.
We thank the staff of the Observatorio Astronómico Nacional in San Pedro
Mártir.
[GCN OPS NOTE(29mar13): Per author's request, the name in the Subject-line
was changed from "130727A" to "130327A".]