GRB 050525A
GCN Circular 3465
Subject
GRB 050525A: ROTSE-III Detection of Possible Counterpart
Date
2005-05-25T00:41:33Z (20 years ago)
From
Eli Rykoff at U of Michigan/ROTSE <erykoff@umich.edu>
E.S. Rykoff (U Mich), S.A. Yost (U Mich), H. Swan (U Mich), report on
behalf of the ROTSE collaboration:
ROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia,
responded to GRB 050525A (Swift trigger 130088). The first image was at
00:08:56.7 UT, 363.5 s after the burst (8.7 s after the GCN notice
time). The unfiltered images are calibrated relative to USNO A2.0. We
detect a 14.7 magnitude, fading source at:
18:32:32.76 +26:20:22.65 (J2000)
start UT mag mlim(of image)
----------------------------------
00:08:56.7 14.7 15.4
This source is not visible in DSS (second epoch), 2MASS or the MPChecker
database.
Continuing observations are in progress.
GCN Circular 3479
Subject
GRB 050525A: Swift-BAT refined analysis
Date
2005-05-25T15:20:37Z (20 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),
M. Chester (PSU), E. Fenimore (LANL), N. Gehrels (GSFC),
D. Hullinger (UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD),
F. Marshall (GSFC), T. Mitani (ISAS), 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:
At 00:02:53 UT Swift-BAT detected GRB 050525A (trigger=130088) (GCN
Circ 3466, Band, et al.). The refined BAT ground position is (RA,Dec)
= 278.140,+26.344, [deg; J2000] {18:32:34, +26:20:38} +- 0.5 arcmin,
(95% containment). This position is consistent with the reported
optical transient positions to within 20 arcsec (GCN Circ 3468,
Rykoff et al.; GCN Circ 3470, Torii et al.).
The image significance is 148 sigma, making GRB 050525 the most
significant BAT-imaged GRB to date. The burst was 26 degrees off
axis, and the partial coding fraction was 85%.
The mask-weighted light curve shows two peaks with duration of 2
and 5 seconds respectively. Each peak has two sub-pulses, which
become more distinct at higher energies. T90 is (8.8 +- 0.5) seconds
and T50 is (5.2 +- 0.5) seconds (15-350 keV; estimated errors include
systematics).
The spectrum has significant curvature, and is not consistent with a
single power law model. Fitting to a cut-off power law yields a
low-energy photon index of 1.0 +- 0.1, Epeak is 79 +- 4 keV. Fitting
to a "Band" GRB spectral model yields the same spectral parameters,
but the "beta" index is unconstrained. Chi2 for the Band model is
the same as for the cutoff power law. The fluence in the 15-350 keV
band is (2.0 +- 0.1) x 10^-5 erg/cm2. The 1-s peak photon flux,
starting at T0+1.63 second in the 15-350 keV band is (48 +- 1)
ph/cm2/s. All the quoted errors are at the 90% confidence level.
GCN Circular 3480
Subject
GRB 050525A: BOOTES simultaneous optical observations
Date
2005-05-25T16:48:14Z (20 years ago)
From
Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>
A. de Ugarte Postigo, M. Jelinek, J. Gorosabel, S. Guziy (IAA-CSIC
Granada),
P. Kubanek, R. Hudec (ASU-CAS, Ondrejov), S. Vitek (FEL-CVUT Praha),
T. J. Soria, R. Fernandez (EELM-CSIC Malaga), J. Fabregat (Univ. de
Valencia)
and A. J. Castro-Tirado(IAA-CSIC), report:
"The BOOTES-1 and BOOTES-2 very wide field cameras, located at INTA-
CEDEA (Huelva, Spain) and EELM-CSIC (Malaga, Spain) respectively, and
distant 200 km each other, observed the region of the sky containing the
SWIFT/BAT error box for GRB 050525 (Band et al. GCN 3466, Markwardt
et al. GCN 3467, Cummings et al. GCN 3469) as part of their routine
observing schedules. 30 s exposures started simultaneously at 00:03:00 UT
(7 s after the onset of the 10 s long burst), with the following frame
starting
at 00:04:00 UT (i.e. covering the late part of the event). A limiting
(unfiltered)
magnitude of 9.0 is derived for any prompt optical flash arising from this
particular GRB. Images are posted at:
http://www.iaa.es/~deugarte/GRBs/050525/GRB050525_wide.gif ".
GCN Circular 3483
Subject
GRB 050525a: Gemini/GMOS Spectra
Date
2005-05-25T21:04:19Z (20 years ago)
From
Josh Bloom at Harvard/CFA <jbloom@cfa.harvard.edu>
R. J. Foley (UCB), H.-W. Chen (MIT), J. Bloom (UCB), J. X. Prochaska
(UCSC) report:
"We obtained a 5x1800 sec dithered exposures of the optical candidate (GCN
3465) of GRB 050525 with GMOS on the Gemini-North telescope starting at
2005 May 25.43 UT. We measure a redshift of z = 0.606, which we assume to
be the redshift of the host galaxy, based on [O III] 5007 and H beta
emission and Ca H&K and Ca I 4228 absorption. There is perhaps very faint
[O II] emission. Further analysis is underway.
This notice may be cited."
GCN Circular 3487
Subject
GRB050525A,optical observation
Date
2005-05-26T11:36:19Z (20 years ago)
From
Shouta Maeno at U.of Miyazaki <shouta@astro.miyazaki-u.ac.jp>
S.maeno,E.sonoda,Y.Tokunaga,M.Yamauchi
(University of Miyazaki)
"We have observed the field covering the error circle of
GRB 050525A (GCN3466 ; Swift BAT Trigger time is 00:02:53 UT)
with the unfiltered CCD camera on the 30-cm telescope
at University of Miyazaki.
The observation was started 12:05:50 UT on May.25.
After co-adding a set of 73 images (12:05:50 - 14:26:49 UT)
of 30 sec exposures, we have compared with the USNO A2.0 catalog.
Preliminary analysis shows there is no new source brighter than
17.7 mag at the position reported by Rykoff et al.(GCN 3468)
and Torii et al.(GCN 3470)
GCN Circular 3488
Subject
GRB 050525a: MDM Observations
Date
2005-05-26T15:35:49Z (20 years ago)
From
Nestor Mirabal at U Michigan <mirabal@umich.edu>
N. Mirabal (U. Michigan), D. Bonfield and K. Schawinski (U. Oxford),
report on behalf of the MDM GRB follow-up team:
"Continuous r'-band photometry of the GRB 050525a afterglow (Rykoff et al.
GCN #3465) was obtained with the RETROCAM imager (Morgan et al.,
astro-ph/0502274) installed on the MDM 2.4m telescope. The data consists
of ~120 points spanning from 4.4 hr to 11.6 hr after the burst. During
this period, the magnitude of the optical afterglow is seen to decline
from R ~ 18.5 to R ~ 19.6, referenced to the R ~ 17.2 USNO star listed
by Rykoff et al. (GCN #3465). A fit to the latter part of the observations
yields a power-law decay slope of -1.38 +/- 0.2, consistent with a
tentative steepening of the decay after ~0.4 days. Further analysis is in
progress.
A graph of the preliminary differential magnitude light curve is available at
http://www-personal.umich.edu/~mirabal/grb050525/lightc.ps"
GCN Circular 3491
Subject
GRB 050525a: SARA Observations
Date
2005-05-26T23:42:35Z (20 years ago)
From
Autumn Homewood at Clemson U <ahomewo@clemson.edu>
Autumn Homewood, Dieter H. Hartmann, Kiran Garimella (Clemson Univ.), Gary
Henson (ETSU), Jeremy McLaughlin (Radford Univ.), Adam Brimeyer (Iowa
State Univ.) report:
We observed a 6x6 arcminute field centered on the optical afterglow of GRB
050525a (GCN 3466), identified by ROTSE-IIIc (GCN 3465) with the SARA 0.9
m Telescope at KPNO. Observations were carried out under good seeing
conditions with the AP7 CCD. We obtained 35 300-second exposures each in
the R-band, in 2 seperate groups. Observations of the first group (27
images) started at UT 2005/05/25 04:40:15, and ended 07:08:07.
Observations of the second group (8 images) began at UT 10:51:29, and
ended at 11:33:59. At the beginning of the first observation run we detect
the afterglow at R = 18.9 +/- 0.2 mag, relative to USNO B2.0 R1.
The SARA home page can be found at
http://www.astro.fit.edu/sara/sara.html
This message may be cited.
GCN Circular 3492
Subject
GRB050525a: optical upper limits
Date
2005-05-27T14:01:46Z (20 years ago)
From
Vasilij Rumjantsev at CrAO <rum@crao.crimea.ua>
V.Rumyantsev (CrAO), G. Kornienko, A. Erofeeva, (UAPhO), A.Pozanenko (IKI)
on behalf of larger GRB follow up collaboration report:
We have observed the refined error box (Cummings et al., GCN 3449) of the
Swift GRB050525a (Band et al., GCN 3466) with 0.4m telescope of Ussuriysk
Astrophysical Observatory (UAPhO), and AT-64 telescope of CrAO on May, 25.
We do not detect OT found by Rykoff et al., (GCN 3465). Upper limits of
unfiltered stacked images calibrated against of R USNO-A2.0 are following:
Mean time Exposure Limiting mag.
May 25
(UT) (s)
13:59 7x60 15.9
19:38 40x60 19.5
The message may be cited.
GCN Circular 3495
Subject
GRB050525a: Radio Observations
Date
2005-05-28T05:31:14Z (20 years ago)
From
Patrick B. Cameron at Caltech <pbc@astro.caltech.edu>
P. B. Cameron (Caltech) and D. A. Frail (NRAO) report on behalf of
the Caltech-NRAO-Carnegie GRB Collaboration:
"We observed the field of GRB050525a (GCN#3466) using the Very Large Array
at a frequency of 22.5 GHz on May 25.42 UT and May 26.36 UT. We detect a
radio source at the position of the optical transient (GCN#3468)."
GCN Circular 3506
Subject
GRB 050525a, SMARTS optical/IR afterglow observations
Date
2005-05-31T20:45:24Z (20 years ago)
From
Bethany Cobb at Yale U <cobb@astro.yale.edu>
B. E. Cobb and C. D. Bailyn (Yale), part of the larger SMARTS
consortium, report:
Using the ANDICAM instrument on the 1.3m telescope at CTIO, we
obtained simultaneous optical/IR imaging of the error region of
GRB 050525a (Band et al. GCN 3466). Several dithered images were obtained
in each filter, with total summed exposure times of 180s in each of BRIYJK
and 120s in each of H and V. Imaging was carried out in a symmetrical
manner so that the mid-exposure time is the same for all final combined
images, in this case being ~5.2 hours post-burst (2005-05-25 05:13 UT).
The afterglow reported by Rykoff et al. (GCNs 3465, 3468) is detected in
each summed image, though the source appears only slightly above the
background. Preliminary comparison with USNO B1.0 stars in the optical
and 2MASS stars in the IR yields the following approximate afterglow magnitudes:
filter AG mag
------ ------
B 18.8+/-0.4
R 18.1+/-0.3
I 18.8+/-0.3
J 17.4+/-0.3
H 16.6+/-0.3
K 16.15+/-0.35
Furthermore, a second epoch of imaging was obtained at a mid-exposure time
of ~53.4 hours post-burst (2005-05-27 05:27 UT). Total summed exposure
times for these images was 36 min in I and 30 min in J. The afterglow
experienced significant decay between epochs and is not detectable in the
second epoch images to a limiting magnitude of I > 21.2+/-0.2
and J > 18.8+/-0.1.
GCN Circular 3507
Subject
GRB 050525a, infrared observations
Date
2005-06-01T16:50:24Z (20 years ago)
From
Peter Garnavich at U of Notre Dame <pgarnavi@nd.edu>
D. Kaplan (MIT), P. Garnavich (Notre Dame), J. Rosenberg (CfA)
and K.Z. Stanek (CfA, Ohio State)
The field of GRB 050525a (Band et al. GCN 3466) was imaged
with the PANIC infrared camera on the Baade telescope of the
Magellan Observatory on May 26 and 27 (UT) and we detect the
afterglow (Rykoff et al. GCN 3465;3468) in the Ks-band on
both nights. Using the 2MASS calibrated stars in the field
we find the afterglow on May 26.278 (UT) to have Ks=19.2+/-0.1.
We also have properly calibrated the FLWO observation obtained
on May 25 (Rosenberg & Garnavich GCN 3471) and combined all three
nights of data. We find that the afterglow light curve in the
K-band is well represented by a power-law decay with a slope
of -1.6 and Ks=18.75 one day after the burst.
This message may be cited.
GCN Circular 3532
Subject
GRB 050525a, Mid-Infrared Observations
Date
2005-06-07T22:53:44Z (20 years ago)
From
Peter Garnavich at U of Notre Dame <pgarnavi@nd.edu>
P. Garnavich (Notre Dame), M. Pahre (CfA), A. Noriega-Crespo (CalTech),
K.Z. Stanek (CfA, OSU), S.T. Holland (GSFC), D. Bersier (STScI),
T. Matheson (NOAO), R. Perna (U. Colorado), K. Krisciunas (Notre Dame)
After confirmation of a bright optical afterglow associated with
GRB 050525 (Band et al. GCN 3466; Rykoff et al. GCN 3465;3468) we
triggered a "target-of-opportunity" (ToO) program on the Spitzer Space
Telescope. Observations began on May 27.26 (UT), or 2.26 days
after the burst, with IRAC imaging followed by IRS spectroscopy,
MIPS mapping and finally another epoch of IRAC images ending on
May 27.56 (UT).
Soon after triggering the ToO, the brightness of the afterglow
switched to a steeper decline rate (Mirabal et al. GCN 3488;
Kaplan et al. GCN 3507) making a rapid response essential.
The first epoch of imaging shows point source at the position of the
afterglow (Rykoff et al. GCN 3468; Yanagisawa et al. GCN 3489)
in the 3.6,4.5 and 8.0 micron IRAC channels and in the 24 micron
MIPS band.
A second epoch of IRAC imaging and MIPS mapping was performed
on May 29. The source is seen to fade in IRAC between the two
epochs of the first visit and is beyond the detection limit
during the second visit. The MIPS 24 micron source is also
seen to fade between visits.
This is the first confirmed detection of a GRB afterglow at
mid-infrared wavelengths. Preliminary estimate of the flux in
the IRAC channels combined with K-band observations of Kaplan et al.
(GCN 3507) suggests a spectral energy distribution consistent
with a power-law. The index of the power-law between 2 and 8 microns
is 1.3+/-0.2. This is surprisingly steep and further analysis
is continuing.
The IRAC 3.6 micron images taken at two epochs can be viewed at:
http://www.nd.edu/~pgarnavi/grb050525/irac.jpg
We thank Nancy Silbermann and the Spitzer Science Center for
rapidly responding to a complex target-of-opportunity observation.
This message may be cited.
GCN Circular 3550
Subject
GRB050525a: HST Observations
Date
2005-06-16T15:43:35Z (20 years ago)
From
Alicia Soderberg at Caltech <ams@astro.caltech.edu>
A. M. Soderberg (Caltech) reports on behalf of the Caltech-NRAO-Carnegie
collaboration:
"We observed the field of GRB050525a (GCN 3466) with HST+ACS/WFC on 12 Jun
2005 UT (t~18 days) as part of our HST Cycle 13 program to study the
supernovae associated with gamma-ray bursts and X-ray flashes (GO 10135;
PI Kulkarni). Coincident with the afterglow position (GCN 3468), we
detect a point source superposed on top of a compact galaxy. Within a 0.5
arcsec aperture, we find the host+OT system to be F625W ~ 24.2 mag (Vega).
Adopting this value as a limit on the brightness of an associated
supernova, we find that the SN associated with GRB050525a is at least ~0.6
magnitudes fainter than SN1998bw at a comparable epoch (assuming
negligible host extinction). Further observations are planned."
GCN Circular 3551
Subject
GRB 050525A: Swift Late-Time Decay Rate
Date
2005-06-21T20:27:28Z (20 years ago)
From
Stephen Holland at USRA/NASA/GSFC/SSC <sholland@milkyway.gsfc.nasa.gov>
GRB 050525A: Swift Late-Time Decay Rate
S. T. Holland, (GSFC/USRA), D. Band (GXFC), A. Blustin (MSSL), P. Boyd
(GSFC/UMBC), F. Marshall (GSFC), K. Mason (MSSL), M. Perri (ASI),
A. Breeveld (MSSL), P. Brown, A. Cucchiara, C. Gronwall, S.
Hunsberger, M. Ivanushkina (PSU), W. Landsman (GSFC), K. McGowan
(MSSL), A. Morgan (PSU), M. De Pasquale, T. Poole (MSSL), P. Roming
(PSU), S. Rosen, (MSSL), P. Schady (MSSL), M. Still (GSFC/USRA),
J. Nousek (PSU), N. Gehrels (GSFC), on behalf of the Swift UVOT team
report:
Swift/UVOT data suggest that there is a jet break at 17,979 s
(0.205 d) after the BAT trigger (Band et al. 2005, GCN 3466) in the
optical/ultraviolet afterglow of GRB 050525A. The observed decay
index after the jet break is -1.73. The Swift/XRT data also show a
late-time break followed by a steep power-law decay. If we
extrapolate the UVOT late-time decay to the time of the HST F625W
observation (Soderberg 2005, GCN 3550) the predicted magnitude of the
optical afterglow is approximately V = 27.4. Therefore the HST
observations suggest that the optical afterglow of GRB 050525A was
approximately three magnitudes brighter at 18 days after the burst
than expected from the fireball model alone. More data are needed to
determine if this additional luminosity is due to a host galaxy or
some form of rebrightening such as a supernova or a dust echo.
GCN Circular 3566
Subject
GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
Date
2005-07-06T18:42:11Z (20 years ago)
From
Melissa Nysewander at UNC,Chapel Hill <mnysewan@physics.unc.edu>
M. Nysewander (North Carolina), J. Flasher (Colorado), F. Hearty
(Colorado), G. Stringfellow (Colorado), J. Walawender (Colorado), D. Q.
Lamb (Chicago), J. Dembicky (APO), J. Barentine (APO), R. McMillan (APO),
B. Ketzeback (APO), D. Reichart (North Carolina), and D. G. York (Chicago)
report on behalf of the FUN GRB collaboration:
Using griz all-sky photometry of a 4.8 arcmin x 4.8 arcminute field
centered on the coordinates of the optical afterglow of GRB 0505025a that
was derived from ARC 3.5-meter SPIcam observations made between 4:00 and
7:00 UT on 2005 June 13, we have calculated the griz magnitudes of 103
sources in the field of GRB 050525a:
http://www.physics.unc.edu/~mnysewan/grb050525a.dat
The astrometry in these files is based on the USNO B1.0-catalogue. The
estimated systematic errors in the astrometry are less than 400mas. The
estimated systematic photometric errors are typically � 0.05 mag in the gri
bands and � 0.06 mag in the z band.
GCN Circular 3567
Subject
GRB 050525a: ARC 3.5-meter Optical and NIR Observations
Date
2005-07-06T19:00:54Z (20 years ago)
From
Don Lamb at U.Chicago <lamb@oddjob.uchicago.edu>
GRB 050525a: ARC 3.5-meter Optical and NIR Observations
J. Flasher (Colorado), F. Hearty (Colorado), G. Stringfellow
(Colorado), J. Walawender (Colorado), D. Q. Lamb (Chicago), D. G. York
(Chicago), G. Wallerstein (Washington), V. Woolf (Washington), S.
Anderson (Washington), J. Dembicky (APO), J. Barentine (APO), R.
McMillan (APO), and B. Ketzeback (APO) report on behalf of the ARC GRB
team of the FUN GRB collaboration:
We observed the afterglow (Rykoff et al., GCN Circular No. 3465;
Malesani et al., GCN Circular No. 3469) of GRB 050525a, a burst
localized by Swift/BAT (Band et al., GCN Circular No. 3466; Markwardt
et al., GCN Circular No. 3467), on the night of May 24th, using SPIcam
and NIC-FPS on the ARC 3.5-meter telescope at Apache Point
Observatory. The observation began at 08.33 UT on 25 May 2005 (8.28
hours after the burst) and ended at 11.07 UT on 25 May 2005 (11.02
hours after the burst). The observation consisted of two 300-second
exposures each in r, i, and z; and a series of 60-, 60-, 10-, and
10-second exposures in Z, J, H, and Ks, respectively. We have
constructed stacked images of the GRB field, corresponding to 10-minute
integrations in r, i, z, and Z; and 20-minute integrations in J, H, and
Ks. We detect the afterglow in all seven filters, and measure J = 18.3
� 0.1 at 09:50 UT (the mid-point time of the J-band observation),
calibrated relative to the 2MASS stars in the field.
NIC-FPS is currently in its commissioning phase.
This message may be cited.
GCN Circular 3568
Subject
GRB 050525a: PROMPT VRcIc Detections
Date
2005-07-06T19:25:10Z (20 years ago)
From
Josh Haislip at U.North Carolina <haislip@physics.unc.edu>
J. Haislip, C. MacLeod, M. Nysewander, A. Foster, J. A. Crain, D. Reichart,
M. Bayliss, J. Kirschbrown, and C. Mack report on behalf of the UNC team of
the FUN GRB Collaboration:
We observed the BAT localization of GRB 050525a (Band et al., GCN 3466)
with PROMPT-5 beginning 5.3 hours after the burst. We detect the afterglow
(Rykoff et al., GCN 3465) in VRcIc across multiple epochs.
Using the field calibration of Nysewander et al. (GCN 3566), we find that
Rc = 19.84 +/- 0.11 mag at a mean time of 8.1 hours after the burst.
PROMPT is still being built and commissioned.
GCN Circular 3660
Subject
Correction to GCN Circ 3474 on GRB050525A
Date
2005-07-21T14:58:14Z (20 years ago)
From
Valentin Pal'shin at Ioffe Inst <val@mail.ioffe.ru>
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and
T. Cline on behalf of the Konus-Wind team report:
In GCN 3474 we reported wrong value of the Konus-Wind fluence
for GRB 050525A (because of missprinting).
The correct value is (2.06 +/- 0.02)10-5 erg/cm2 .
The reported peak flux and spectral parameters were correct.
We thank Dr. Hurley for noticing this error.
GCN Circular 3721
Subject
Correction to GCN Circ 3476 on GRB050525A
Date
2005-08-01T14:46:46Z (20 years ago)
From
Jean-Luc Atteia at Lab d Astrophys.,OMP,Toulouse <atteia@ast.obs-mip.fr>
J-L. Atteia & A. Pelangeon (LAT-OMP) report:
Taking into account the revised value of the fluence of GRB 050525a provided
by Golenetskii et al. in GCN 3660, we have re-computed the pseudo-redshift of
GRB 050525a (using the method described in Atteia, 2003, A&A, 407, L1).
We find a pseudo-redshift pz=0.64 +/- 0.1, in good agreement with the
spectroscopic redshift z=0.606