GRB 050331
GCN Circular 3155
Subject
GRB 050331: Swift XRT Position
Date
2005-03-31T18:23:59Z (20 years ago)
From
David Burrows at PSU/Swift <dxb15@psu.edu>
L. Angelini (GSFC), J. L. Racusin, S. Hunsberger, D. N. Burrows, J. E.
Hill, J. A. Kennea, D. C. Morris, D. Grupe, J. A. Nousek (PSU), J. P.
Osborne, K. L. Page, M. R. Goad, A. P. Beardmore, O. Godet, A. F. Abbey, A.
A. Wells (U. Leicester), S. Campana, A. Moretti, C. Pagani, P. Romano, G.
Tagliaferri, G. Chincarini (INAF-OAB), G. Cusumano, V. La Parola, V.
Mangano, T. Mineo (INAF-IASF/Palermo), P. Giommi, M. Capalbi, M. Perri, F.
Tamburelli (ASDC), F. Marshall, N. White, N. Gehrels (GSFC), P. Roming, P.
Meszaros (PSU), P. Schady (MSSL), report on behalf of the Swift XRT team:
The Swift spacecraft executed a prompt slew to GRB050331 (discovered by the
Swift BAT). The XRT found a bright source located at the following position:
RA(J2000) = 09:22:57,
Dec(J2000) = -41:26:18
We estimate an uncertainty of about 6 arcseconds. This source is located
1.5 arcminutes from the BAT position.
GCN Circular 3156
Subject
Swift-BAT detection of GRB 050331
Date
2005-03-31T18:40:05Z (20 years ago)
From
David Palmer at LANL <palmer@nis.lanl.gov>
D. Palmer (LANL), L. Barbier (GSFC), S. Barthelmy (GSFC),
J. Cannizzo (GSFC/UMBC), J. Cummings (GSFC/NRC), E. Fenimore (LANL),
N. Gehrels (GSFC), D. Hullinger (UMD), H. Krimm (GSFC/USRA),
C. Markward (GSFC/UMD), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC),
G. Sato (ISAS), A. Smale (NASA HQ) M. Suzuki (Saitama), J. Tueller (GSFC)
on behalf of the Swift team:
At 17:11:53 UT Swift-BAT triggered on a burst GRB 050331, and
automatically slewed. A few of the standard GCN/Swift Notices were
delayed, because
this burst occurred during a regular Malindi telemetry downlink session.
The BAT-derived position is RA,Dec=140.771,-41.430 (J2000). We note this
is 91 arcsec from the XRT Position GCN Notice. The lightcurve
has some low-significance peaks for the first ~15 sec, then two peaks
at T+15 and T+18 sec (of 1 and 2 sec duration, resp.) with a total
burst duration of ~20 sec. The peak count rate is ~1000 cnts/sec.
--
GCN Circular 3157
Subject
GRB 050331: Swift UVOT Source
Date
2005-03-31T19:03:26Z (20 years ago)
From
Pete Roming at PSU <roming@astro.psu.edu>
M. Still (GSFC/USRA), W. Landsman (GSFC), A. Morgan, C. James (MSSL), S.
Hunsberger (PSU), A. Breeveld (MSSL), P. Roming (PSU), K. Mason, P. Schady
(MSSL), M. Ivanushkina (PSU), T. Poole (MSSL), C. Gronwall (PSU), A.
Blustin (MSSL), P. Brown (PSU), S. Rosen, K. McGowan, M. De Pasquale
(MSSL), P. Boyd (GSFC/UMBC), S. T. Holland (GSFC/USRA), M. Carter, H.
Huckle (MSSL), P. Broos (PSU), T. Kennedy, P. Smith, B. Hancock (MSSL), S.
Koch (PSU), S. Zane (MSSL), D. Hinshaw (GSFC/SPSYS), J. Nousek (PSU), N.
Gehrels (GSFC), on behalf of the Swift UVOT team.
The Swift Ultra-Violet/Optical Telescope (UVOT) began settled observations
of the field of GRB 050331 (Angelini et al; GCN 3155) at 17:14:09 UT, 135s
after the BAT trigger. The first data taken after spacecraft settling was
a 100s V image, sent directly to the ground through the TDRSS system, with
pixel binning of 8x8 to reduce telemetry. Binned pixel sizes are 4x4 arcsec
and the field of view is 5.3x5.3 arcmin. An extremely bright source,
consistent with the XRT position, is found in the image. A magnitude can
not be determined at this time due to saturation of the detector (13.0 mag).
GCN Circular 3159
Subject
GRB050331: No Afterglow Detected
Date
2005-03-31T20:47:13Z (20 years ago)
From
Aaron Price at AAVSO <aaronp@aavso.org>
B. Monard and A. Price report on behalf of the AAVSO International High Energy Network on
optical observations of the field of GRB050331 (GCN#3156 Palmer et al.).
A field centered on the coordinates of the XRT position in GCN #3155 (Burrows et al.) was
observed at midpoint time of 19:03 UT and compared with the DSS/POSS red plate. The CCD
was unfiltered but with a red zeropoint response.
No new source was identified down to a limiting magnitude (SNR=3) of 20.
Full details on the report is below along with a link to the FITS image:
Report filed on March 31 22:08 UT
Name: Berto Monard
email: bmonard@mweb.co.za
Site: Bronberg Observatory / CBA Pretoria
Location: -25 � 54' 48", 28� 26' 44"E
Elevation: 1590m
Scope: LX200 31cm
ScopeFocalRatio: f/3.7
CCDVendor: SBIG, ST-7XME
CCDPixelScale: about 1.8 arcsec /pixel
CCDFOV: 21 arcmin (E/W) x 14 arcmin (N/S)
Object: GRB 050331
ObsDate: 050331
ObsMidPointTime: 19 03 UT
Exposure per frame: 28 sec
NumberOfFrames: 35 stacked
Filters: none
Processing: dark/flat
Seeing: fair (about 3.5 arcsec)
LimitingMag: about 21CR for stack
Sky: open / no moon / object near zenith
afterglowmag: none down to magnitude 20CR
Report: the observed star field was set to be centered on 09 22 57 -41 25
48.
The obtained deep image was compared visually to a DSS-2 red image over the
entire error box of 4 arcmin.
No new object was found to an estimated limit of 20 CR and no further
observations are planned.
FITS image is located at http://www.aavso.org/tmp/grb050331.fits