GRB 050502B
GCN Circular 4113
Subject
GRB 050502b: Optical limit
Date
2005-10-19T04:41:38Z (20 years ago)
From
Ken ichi Torii at RIKEN <torii@ess.sci.osaka-u.ac.jp>
K. Torii (Osaka U.) reports on behalf of the ART collaboration:
The error region of the bright GRB 050502b (Falcone et al. GCN 3330)
was observed by the 14 inch Automated Response Telescope. Ic band
imaging was started at 2005 May 2 10:19:30 UT (54 minutes after the
burst) and 60s exposure was repeated.
The optical afterglow (Rich et al. GCN 3338) is not detected in our
frames and the following 3-sigma upper limit is derived for a stacked
image.
------------------------------------------
StartUT-EndUT Filter Limit Exposure
------------------------------------------
10:55:59-13:00:20 Ic >18.6 87x60s
------------------------------------------
GCN Circular 3421
Subject
GRB050502b: Early Observation
Date
2005-05-13T13:59:21Z (21 years ago)
From
Koji Noda at ICRR,U of Tokyo <nodak@icrr.u-tokyo.ac.jp>
M. Sasaki, N. Manago, K. Noda, Y. Asaoka report on behalf of the Ashra collaboration:
We have observed the field of GRB050502b (09:25:40 UT) covering the SWIFT XRT error circle
(Pagani et al., GCN 3333) by the Ashra-AFT (Automated Follow-up for Transients) telescope
at the Haleakala observatory in Hawaii (latitude = 20d 42' 37" N, longitude = 156d 15' 31" W,
altitude = 3020m). The telescope (12" Meade LX200GPS with a KAI-2020M CCD) is served as a
follow-up detector to quickly respond to triggers from Ashra optical transient survey monitor
as well as from GRB satellites.
The telescope automatically slewed to the GRB and took the first image of 1.4sec-exposure
at 09:26:36 UT (56 seconds after the burst and 32 seconds after the BAT alert socket).
We also took following 363 images of 4sec-exposure every 9 to 10 seconds (09:26:36 UT - 10:25:47 UT).
These images are unfiltered to maximize the detection sensitivity, of which peak is between B and V.
No new source was found within the SWIFT XRT position. From the earliest 4 images and the co-added
images (3 x 4sec, 25 x 4sec), we preliminarily obtained 4-sigma limiting magnitudes of B1 and R1
in the USNO-B1.0 catalog as follows.
-----------------------------------------------------
start end exposure limit mag.
after GRB (s) (s) B1 R1
-----------------------------------------------------
56.0 57.4 1.4 16.2 14.6
66.0 70.0 4.0 16.9 15.5
76.0 80.0 4.0 16.2 14.6
85.0 89.0 4.0 16.2 14.6
-----------------------------------------------------
66.0 89.0 12.0 17.2 16.2
66.0 294.0 100.0 18.5 17.0
-----------------------------------------------------
URL: http://www.icrr.u-tokyo.ac.jp/~ashra/GRB050502b/
This message can be cited.
GCN Circular 3358
Subject
GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
Date
2005-05-05T10:38:37Z (21 years ago)
From
Brian Schmidt at RSAA, ANU (MSSSO) <brian@mso.anu.edu.au>
S. Bradley Cenko, Derek B. Fox (Caltech), Joshua Rich, Brian Schmidt
(ANU), Jessie Christiansen (UNSW), and Edo Berger (Carnegie) report:
We have further analyzed our images of the field of GRB050502b (GCN
3330) taken with the 1-m ANU telescope (GCN 3338). Additionally, we
have imaged the field with the automated Palomar 60-inch telescope
(P60). Observations at the P60 consisted of 10 x 120 s exposures in the
Gunn i band taken at a mean epoch of 5:40 4 May 2005 UT (43.8 hours
after the burst).
Based on extrapolations from the 2MASS and USNO-B2 catalogs, we adopt
values of V=16.7, I=15.8, R=16.1 for the star located at RA =
09:30:12.616, Dec = +17:00:05.55 (J2000.0). We find the magnitude of
the afterglow candidate identified by Rich, Schmidt, and Christiansen
(GCN 3338) as follows:
Filter Facility UT Age Limit (3-sig) or measure
========================================================
V ANU1m 9:35 May 2 9.5 min V>20.7
V ANU1m 9:41 May 2 15 min V>20.2
V ANU1m 9:43 May 2 18 min V>20.8
V ANU1m 9:46 May 2 20 min V>21.8
I ANU1m 9:58 May 2 23 min I=19.84+/-0.09
i P60 5:40 May 4 43.8 hr i>21.7
We therefore identify this source as the afterglow of GRB050502b. To
reiterate the coordinates (J2000.0):
RA 09:30:10.024
DEC +16:59:48.07
Finally, we note the spectral slope at early times, beta > 2.9,
indicates that GRB050502b may be either highly extinguished or at
moderately high redshift.
GCN Circular 3357
Subject
GRB050502b: Afterglow Confirmation
Date
2005-05-05T06:25:50Z (21 years ago)
From
S. Bradley Cenko at Caltech <cenko@srl.caltech.edu>
S. Bradley Cenko, Derek B. Fox (Caltech), Joshua Rich, Brian Schmidt
(ANU), Jessie Christiansen (UNSW), and Edo Berger (Carnegie) report:
We have further analyzed our images of the field of GRB050502b (GCN
3330) taken with the 1-m ANU telescope (GCN 3338). Additionally, we
have imaged the field with the automated Palomar 60-inch telescope
(P60). Observations at the P60 consisted of 10 x 120 s exposures in the
Gunn i band taken at a mean epoch of 5:40 4 May 2005 UT (43.8 hours
after the burst).
Based on extrapolations from the 2MASS and USNO-B2 catalogs, we adopt
values of V=16.7, I=15.8, R=16.1 for the star located at RA =
09:30:12.616, Dec = +17:00:05.55 (J2000.0). We find the magnitude of
the afterglow candidate identified by Rich, Schmidt, and Christiansen
(GCN 3338) as follows:
Filter Facility UT Age Limit (3-sig) or measure
========================================================
V ANU1m 9:35 May 2 9.5 min V>20.7
V ANU1m 9:41 May 2 15 min V>20.2
V ANU1m 9:43 May 2 18 min V>20.8
V ANU1m 9:46 May 2 20 min V>21.8
I ANU1m 9:58 May 2 23 min I=19.84+/-0.09
i P60 5:40 May 4 43.8 hr i>21.7
We therefore identify this source as the afterglow of GRB050502b. To
reiterate the coordinates (J2000.0):
RA: 09:30:10.024
Dec: +17:00:05.55
Finally, we note the spectral slope at early times, beta > 2.9,
indicates that GRB050502b may be either highly extinguished or at
moderately high redshift.
GCN Circular 3350
Subject
GRB 050502b, V band Observations
Date
2005-05-04T09:49:37Z (21 years ago)
From
Kuntal Mishra at ARIES,Nainital,India <kuntal@upso.ernet.in>
Kuntal Misra, S. B. Pandey (ARIES Naini Tal), on behalf of larger Indian
GRB collaboration
We observed the SWIFT burst (trigger = 116116) using 1-m Sampurnanand
Telescope at ARIES, Naini Tal. The observations were carried out in V band
(12*300sec). In the combined V band image (around May 02.654 UT, mean
epoch of observations), we did not reveal any new source down to ~ 21.5
mag, in comparison to a nearby star 09:30:06.62 +16:58:59.0 (V mag 15.992).
This message may be cited.
GCN Circular 3346
Subject
GRB 050502b, Optical observations
Date
2005-05-04T06:49:22Z (21 years ago)
From
T.P. Prabhu at Indian Astro. Obs. <tpp@crest.ernet.in>
The field of GRB 050502b (GCN 3330, 3333) was observed by B.C. Bhatt,
S. Ramya and G.C. Anupama on 2005 May 2, 14:45 UT, using the 2-m Himalayan
Chandra Telescope, Indian Astronomical Observatory, Hanle. The co-added 40
min (4 x 600s) R frame does not show any optical transient down to
R ~ 22.5 mag.
This message may be quoted in publications.
-- T.P. Prabhu, on behalf of the GRB followup team of Indian Astronomical
Observatory, Hanle
GCN Circular 3339
Subject
GRB050502B Swift-BAT refined analysis
Date
2005-05-03T01:15:39Z (21 years ago)
From
Jay R. Cummings at NASA/GSFC/Swift <jayc@milkyway.gsfc.nasa.gov>
J. Cummings (GSFC/NRC), L. Barbier (GSFC), S. Barthelmy (GSFC),
E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (UMD),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL),
A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS),
M. Suzuki (Saitama), M. Tashiro (Saitama U.), J. Tueller (GSFC),
on behalf of the Swift/BAT team:
At 09:25:40 UT, the Swift Burst Alert Telescope (BAT) triggered
and located GRB050502B (trigger=116116) (GCN Circ 3330, Falcone
et al.). The refined BAT ground position is (RA,Dec) = 142.543,
+17.002, [deg; J2000] +- 3 arcmin, (95% containment). This is
24 arc seconds from the position determined by the XRT (GCN Circ
3333, Pagani, et al.). The burst was 10 degrees off the Swift
boresight, within the fully-coded BAT field of view.
The BAT mask-weighted light curve shows one main peak of about 6
seconds duration centered at the trigger time preceded by two
smaller peaks 16 and 10 seconds earlier with a softer spectrum.
T90 (15-350 keV) is (17.5 +- 0.2) seconds (estimated error
including systematics).
The spectrum is well fit by a single power law with photon index
of 1.6 +- 0.1. The fluence in the 15-350 keV band is
(8.0 +- 1.0) x 10^-7 erg/cm2. The peak photon flux in the 15-350
band is (1.73 +- 0.15) ph/cm2/s. All the quoted errors are at the
90% confidence level.
We note that this burst appears to be well-suited for ground
follow-up observations, as it is located 90 degrees from the Sun,
180 degrees from the Moon, close to the ecliptic, and away from
the Galactic center.
GCN Circular 3338
Subject
GRB050502B: I band source in XRT error circle
Date
2005-05-03T00:04:58Z (21 years ago)
From
Brian Schmidt at RSAA, ANU (MSSSO) <brian@mso.anu.edu.au>
Joshua Rich, Brian Schmidt (Australian National University) and Jessie
Christiansen (UNSW) report on behalf of a larger collaboration:
Images taken with ANU 1m telescope show a source within the
SWIFT XRT error circle (Pagani et al., GCN 3333) at I=19.5 located at
RA=09:30:10.024 DEC=+16:59:48.07 J2000. This object does not vary by
more than +/- 0.1 mag from 2 May 2005 UT 9:58 through to UT 11:05. The
object is not
detected in V to V>21. The object is 4.01+/-0.1 mag fainter than the
star located at
RA=09:30:12.616 DEC=+17:00:05.55 in I.
This message may be cited.
GCN Circular 3334
Subject
GRB 050502b : optical observation at Lulin observatory
Date
2005-05-02T15:47:37Z (21 years ago)
From
Yuji Urata at RIKEN <urata@crab.riken.go.jp>
K. Sanchawala, W.L. Wu, K.Y. Huang, W.H. Ip(NCU),
Y. Qiu, W. Zhou (BAO), Y.Q. Lou (THCA), Y. Urata (RIKEN)
on behalf of the EAFON report:
" We have imaged the Swift XRT position of GRB 050502b (Pagani. C. et
al., GCN 3333) using 1-m telescope at Lulin Observatory, Taiwan. The R
band observations started from 13.45 UT (~ 3.98 hours after the
burst). The limiting magnitude of R-band co-added image is R~21.8
compared with USNO-B1.0 stars. No source was detected under the
limiting magnitude at the XRT position."
This message may be cited.
GCN Circular 3333
Subject
GRB 050502b: Swift XRT Position
Date
2005-05-02T12:53:52Z (21 years ago)
From
David Burrows at PSU/Swift <dxb15@psu.edu>
C. Pagani, A. Falcone, D. N. Burrows, J. Kennea, S. Kobayashi (PSU), F.
Marshall, and Neil Gehrels (GSFC) report on behalf of the Swift XRT team:
The Swift XRT observed GRB 050502b (Falcone et al., GCN 3330) beginning at
09:26:43 UT. As reported in GCN 3330, the XRT obtained only 5 photons in
its initial centroiding image and was not able to report a prompt
centroid. Analysis of the first orbit of data reveals a bright, transient,
uncataloged X-ray source at the following position:
RA(J2000) = 09:30:10.1
Dec(J2000) = +16:59:44.3
The estimated uncertainty is 5 arcseconds radius (90% containment). We
note that this position is 23.1 arcseconds from the BAT position reported
in GCN 3330, and 141 arcseconds from the UVOT position reported in GCN 3330.
GCN Circular 3331
Subject
GRB050502B: Optical Limits from ANU 1m
Date
2005-05-02T11:55:43Z (21 years ago)
From
Brian Schmidt at RSAA, ANU (MSSSO) <brian@mso.anu.edu.au>
Joshua Rich, Brian Schmidt (Australian National University) and Jessie
Christiansen (UNSW) report on behalf of a larger collaboration:
Images taken with ANU 1m telescope show no source at the position of the
SWIFT OT reported by Falcone et al. (GCN 3330) at the following
(approximate) limits
Band Time (UT) Age (Minutes) Limit
V 9:35 9 V>19
V 9:48 22 V>21
I 9:58 32 I>20.5
This message may be cited.
GCN Circular 3330
Subject
Swift Detection of the Bright Burst GRB050502b
Date
2005-05-02T10:42:36Z (21 years ago)
From
David Burrows at PSU/Swift <dxb15@psu.edu>
A. Falcone, D. N. Burrows, M. Chester (PSU), P. Schady (MSSL),
J. Cummings (GSFC/NRC), D. Palmer (LANL), C. Pagani (PSU), B. Zhang (UNLV),
K. Page, M. Goad (U.Leicester), N. Gehrels (GSFC)
on behalf of the Swift Team.
At 09:25:40 UT, the Swift Burst Alert Telescope (BAT) triggered
and located GRB050502b (trigger=116116). The BAT on-board
calculated location is RA, Dec = 142.543, +17.002
(09:30:10, +17:00:07) (J2000) with an uncertainty of
3 arcmin (radius, 3-sigma, including estimated
systematic uncertainty). The BAT light curve showed a 7-second
long peak with complex structure from t-4 to t+3. The
maximum count rate was 4000 counts per second (15-350 keV)
in the 1 second time interval centered around t+1.
The spacecraft slewed promptly and the XRT began observations
at 09:26:43 UT. The initial centroiding image detected only
5 counts, insufficient to produce a centroid. Further analysis
will require the ground-processed data, which will be available
at the Swift MOC at about 12:30 UT.
The Swift Ultra Violet/Optical (UVOT) observations began at
09:26:40 UT, 60 seconds after the BAT trigger. The first
data taken after the spacecraft settled was a 100 sec
exposure using the V filter with the midpoint of the
observation at 135 sec after the BAT trigger. This image
was sent directly to the ground via TDRSS with the FOV pixel
binning set at 8 x 8 to reduce telemetry. A comparison against
the USNO-B1 reveals a new source inside the BAT error circle
at RA, Dec 09:30:12.58, +17:02:00.7 (J2000). This is 118 arcseconds from
the BAT position. The V-band magnitude was 17.7 +/- 0.1.