GRB 050701
GCN Circular 3556
Subject
Swift trigger 143708 is really GRB 050701
Date
2005-07-01T12:38:19Z (20 years ago)
From
Hans Krimm at NASA-GSFC <krimm@milkyway.gsfc.nasa.gov>
P. Boyd (GSFC/UMBC), L. Barbier (NASA GSFC),
D. Burrows (PSU), N. Gehrels (NASA GSFC), M. Goad (Leicester),
C. Hurkett (Leicester), M. Ivanushkina (PSU), H. Krimm (GSFC/USRA),
C. Markwardt (GSFC/UMD), K. Page (Leicester U), D. Palmer (LANL),
A. Parsons (NASA GSFC), T. Poole (MSSL), P. Roming (PSU)
At 11:42:59 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB050701(trigger=143708). The BAT on-board
calculated location is RA,Dec 227.287d -59.419d
{+15h 09m 09s, -59d 25' 06"} (J2000) with an uncertainty of 3 arcmin
(radius, 3-sigma, including estimated systematic uncertainty). The
detection significance in the image plane is 14.2 sigma.
The BAT light curve showed a complex multipeaked structure
with a duration of about 40 seconds. The peak
count rate of 5000 counts/sec (15-350 keV) was measured by
BAT in the 1-sec time interval centered on T+15 sec after the trigger.
Because this burst was 40 arcminutes from a known source
(PSR 1509-58) it was incorrectly classified on-board
and so Swift did not automatically slew to observe this burst.
A target of opportunity observation is being planned.
GCN Circular 3557
Subject
GRB 050701: Swift XRT afterglow position
Date
2005-07-01T16:56:50Z (20 years ago)
From
David Burrows at PSU/Swift <dxb15@psu.edu>
J. L. Racusin, D. N. Burrows, D. C. Morris, D. Grupe, J. Nousek (PSU), C.
Hurkett, J. P. Osborne, K. L. Page, M. R. Goad, A. A. Wells (U. Leicester),
W. Voges (MPE), and N. Gehrels (GSFC) report on behalf of the Swift XRT team:
The Swift BAT instrument detected GRB 050701 at 11:42:59 UT on 01 July 2005
(Boyd et al. 2005, GCN 3556). The BAT instrument incorrectly classified
this as a known source in the on-board catalog and the observatory did not
make an automated slew. A ToO observation was uploaded at about 13:00
UT. The spacecraft slewed to the target and XRT began taking data in
Manual State/PC mode at about 13:19:05 (5766 s post-burst). Based on XRT
quick-look data products at the MOC, we find a faint uncataloged X-ray
source located at:
RA(J2000) = 15:09:01.9,
Dec(J2000) = -59:24:56.3.
We estimate an uncertainty of about 6 arcseconds radius (90%
containment). This source is located 55 arcseconds from the BAT position
in GCN 3556. Further XRT results will be released as the standard pipeline
data products are analyzed.
GCN Circular 3558
Subject
GRB050701: Swift-BAT Refined analysis
Date
2005-07-01T17:42:40Z (20 years ago)
From
Hans Krimm at NASA-GSFC <krimm@milkyway.gsfc.nasa.gov>
H. Krimm (GSFC/USRA), S. Barthelmy, L. Barbier (GSFC),
J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC),
D. Hinshaw (GSFC/SPSYS), D. Hullinger (GSFC/UMD), C. Markwardt (GSFC/UMD),
P. Meszaros (PSU), D. Palmer (LANL), A. Parsons (GSFC),
T. Sakamoto (GSFC/NRC), G. Sato (ISAS), M. Suzuki (Saitama),
J. Tueller (GSFC)
on behalf of the Swift-BAT team:
Using the full data set from the recent telemetry downlink,
further analysis of Swift-BAT GRB050701 (GCN Circ 3556)
over the time interval of T-4.7 to T+8.9 sec with a power law fit
yields an index of 1.62 +-0.07 and a fluence of 1.9x10^-6 erg/cm2
in the 15-350 keV band and a peak flux of 3.5 +- 0.2 ph/cm2/sec
(also 15-350 keV) in a 1-sec wide window starting at T+7.3 sec.
The lightcurve has two main peaks with some pre-trigger emmission
starting at T-7 sec, and small peak at T+27 sec.
This burst occurred within the 40-arcmin search radius
of the PSR 1509-58 source in the on-board catalog. Hence
the on-board trigger-type identification yielded a match.
This radius has been reduced to a more reasonable value
of 20 arcmin for this post-verification era.
GCN Circular 3559
Subject
Swift UVOT observations of GRB 050701
Date
2005-07-01T22:07:19Z (20 years ago)
From
Massimiliano de Pasquale at MSSL-UCL <mdp@mssl.ucl.ac.uk>
M. De Pasquale (MSSL), P. Boyd (GSFC), A. Blustin (MSSL),
J. Nousek (PSU), W. Voges (MPE), on behalf of the Swift
UVOT team
The Swift UVOT began observing the field of GRB 050701
(Boyd et al, GCN 3356) 1.6 hours after the trigger.
No new source is detected within the 6 arcsec radius XRT
error circle (Racusin et al., GCN 3557).
We report the following 3 sigma magnitude upper limits.
Filter T_middle(s) Exposure(s) Upper limit
V 13730 670 19.61
B 11940 900 20.78
U 7860 637 20.17
UVW1 7110 900 20.5
UVM2 6210 900 20.5
UVW2 12890 900 20.71
The magnitudes are based on preliminary zero-points, measured
in orbit, and will require refinement with further calibration.
GCN Circular 3560
Subject
GRB 050701: Refined XRT analysis
Date
2005-07-01T22:38:03Z (20 years ago)
From
David Burrows at PSU/Swift <dxb15@psu.edu>
C. Hurkett, J. P. Osborne, K. L. Page, M. R. Goad, A. A. Wells
(U. Leicester), J. L. Racusin, D. N. Burrows, D. C. Morris, D. Grupe,
M. Chester (PSU), F. Marshall and N. Gehrels (GSFC) report on behalf of
the Swift XRT team:
We have analyzed the Swift XRT data from the first four orbits of GRB
050701 ToO (Racusin et al., GCN3557; Krimm et al., GCN 3558). The X-ray
source is clearly fading during this time period, indicating that it is the
GRB afterglow. The refined
coordinates for the X-ray afterglow are:
RA(J2000) = 15h 09m 01.8s, Dec(J2000) = -59:24:50.1
The estimated uncertainty is 6 arcseconds radius (90% containment).
A preliminary spectral fit to all of the PC data gives a spectral power
law photon index of 1.8 +/- 0.5 in the [0.2-10] keV band, assuming
Galactic absorption (5.6E20cm^-2). The average estimated flux for this
model in the 2.0-10.0 keV range is approximately 1.9E-12 ergs cm-2 s-1 at
6770s after the trigger time. A preliminary estimate of the X-ray decay
power-law index is alpha = -0.66.
GCN Circular 3562
Subject
GRB 050701, optical observations
Date
2005-07-02T21:20:02Z (20 years ago)
From
Alberto Castro-Tirado at LAEFF-INTA <ajct@laeff.esa.es>
T. Britton (Univ. of Auckland), J. Gorosabel (IAA-CSIC Granada),
P. Tristram, Ph. Yock (Univ. of Auckland), M. Sasaki, C. Okada,
S. Nakamura and K. Kamiya (Nagoya Univ.), O. Bogdanov (Nikolaev
State Univ.), S. Guziy and A. J. Castro-Tirado (IAA-CSIC),
report:
Following the detection of GRB 050701 by Swift/BAT (Boyd et
al, GCN 3356), we obtained R- & I-band images starting 5.0
hours after the trigger, at the 0.6 m and 1.8 m telescopes at
Mt. John Astronomical Observatory. No new source is detected
within the 6" radius XRT error circle (Hurkett et al., GCN 3560)
down to the DSS-2 limiting magnitude. We also notice that there
is considerable extinction towards this line of sight.
This message can be cited.
GCN Circular 3563
Subject
GRB 050701
Date
2005-07-05T00:01:42Z (20 years ago)
From
Michael Schwartz at Tenegra Obs. <mbs@tenagraobservatories.com>
Paul Luckas (Tenagra W. Australia) , Odd Trondal (Tenagra Norway) and
Michael Schwartz (Tenagra Arizona) report:
Following the detection of GRB 050701 by Swift/BAT (Boyd et al, GCN
3356), we obtained unfiltered images starting 14.7 hours after the
trigger, using one of Tenagra observatory's 0.35-m telescopes at Perth,
Western Australia. No new source was detected within the 6" radius XRT
error circle (Hurkett et al., GCN 3560) down to the DSS-2 limiting
magnitude.
This message may be cited.
-Michael Schwartz, on behalf of the Tenagra Observatories GRB followup team.