GRB 080325
GCN Circular 7512
Subject
GRB 080325: Swift detection of a burst
Date
2008-03-25T04:25:22Z (17 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
L. Vetere (PSU), P. J. Brown (PSU), D. Grupe (PSU),
C. B. Markwardt (CRESST/GSFC/UMD), C. Pagani (PSU),
D. M. Palmer (LANL), J. L. Racusin (PSU), M. C. Stroh (PSU) and
T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:
At 04:09:17 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 080325 (trigger=307604). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 277.895, +36.511 which is
RA(J2000) = 18h 31m 35s
Dec(J2000) = +36d 30' 38"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). Because this is a 64-sec long image trigger, the
TDRSS lightcurve does not show any significant signal (as is typical).
The XRT began observing the field at 04:11:49.2 UT, 151.9 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 277.8920, +36.5221 which is equivalent to:
RA(J2000) = 18h 31m 34.0s
Dec(J2000) = +36d 31' 19.5"
with an uncertainty of 4.7 arcseconds (radius, 90% containment). This
location is 40 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to assess possible
redshift constraints using X-ray spectroscopy and the nH-z relation
from Grupe et al. (2007).
UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm)
filter starting 162 seconds after the BAT trigger. No afterglow candidate has
been found in the initial data products. Image catalog data are not available
at this time. 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 0.06.
Burst Advocate for this burst is L. Vetere (vetere AT astro.psu.edu).
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 7513
Subject
GRB 080325: Enhanced Swift-XRT position
Date
2008-03-25T11:21:05Z (17 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.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 199 s of overlapping XRT Photon Counting mode and UVOT
data for GRB 080325, 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 = 277.89272, +36.52381 which is equivalent
to:
RA (J2000): 18h 31m 34.25s
Dec (J2000): +36d 31' 25.7"
with an uncertainty of 2.6 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
http://www.swift.ac.uk/xrt_positions/Goad.pdf), the current algorithm is an
extension of this method.
This circular was automatically generated, and is an official product of the
Swift-XRT team.
GCN Circular 7515
Subject
GRB 080325: NIR afterglow candidate
Date
2008-03-25T15:43:08Z (17 years ago)
From
Adria C. Updike at Clemson U <aupdike@clemson.edu>
Adria C. Updike, Brian C. Donehew, Ian Oliver, and Dieter H. Hartmann
(Clemson University) report:
We imaged the field of GRB 080325 (Vetere et al., GCN 7512) with the KPNO
2.1m + FLAMINGOS in the J band beginning 5 hours and 42 minutes after the
trigger. Within the enhanced XRT position (Osborne et al., GCN 7513), we
detect a source at RA = 18:31:34.185, Dec = +36:31:19.60 (+/- 2
arcseconds).
Days after trigger Band Magnitude
--------------------------------------------------
0.23775 J 18.76 +/- 0.14
0.25022 J 18.85 +/- 0.13
0.26427 J 19.42 +/- 0.26
Magnitudes are derived relative to the 2MASS catalog. This sequence
suggests a fading source. Further observations are required to confirm
this detection.
This message may be cited.
GCN Circular 7516
Subject
GRB 080325: Early observations from OSN
Date
2008-03-25T18:33:39Z (17 years ago)
From
Antonio Deugarte at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (ESO, Chile), A. Sota,
J.Gorosabel, A.J. Castro-Tirado (IAA-CSIC) report,
We have observed the field of GRB 080325 (Vetere et al.
GCN 7512) with the 1.5m OSN telescope at Sierra Nevada
Observatory (Granada, Spain) starting at 04:23:01 UT, 12.48
minutes after the burst. Inside the initial XRT error box
there is an object with coordinates R.A.: 18:31:34.13
Dec.: +36:31:19.8 (J2000 +/- 0.5"), which is also present in
the DSS, consistent with the coordinates reported by
Updike et al. (GCN 7515). Inside the refined XRT error box
(Osborne et al. GCN 7513) we do not detect any new source
down to the following 3-sigma limits (t-t0 being the mean
observing time since the GRB):
(t-t0) (min) | Exp. time (s) | I-band limit
12.65 | 20 | > 19.5
14.36 | 9x20 | > 20.8
39.46 | 2300s | > 21.8
This message may be cited
GCN Circular 7518
Subject
GRB 080325: Swift/UVOT Upper Limits
Date
2008-03-25T20:25:03Z (17 years ago)
From
Peter Brown at PSU <pbrown@astro.psu.edu>
P. J. Brown and L. Vetere (PSU) report on behalf
of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field
of GRB 080325 (trigger=307604) starting 163 s after
the BAT trigger (Vetere et al., GCN Circ. 7512).
We do not detect an optical/uv afterglow at the
enhanced XRT position (Osborne et al., GCN Circ. 7513),
or NIR candidate (Updike et al., GCN Circ. 7515) in
the initial finding chart observations or subsequent
summed images down to the following 3 sigma upper limits:
Filter T_start (s) T_stop Exposure MagLimit
white 163 262 98 >20.6
white 163 5905 392 >21.5
v 269 513 240 >19.3
v 269 6297 419 >19.6
b 5501 5700 197 >20.6
u 4131 22211 353 >20.9
uvw1 3925 21975 2371 >21.8
uvm2 3720 10211 891 >21.1
uvw2 5912 6111 197 >20.1
The above magnitudes are not corrected for the Galactic
extinction corresponding to a reddening of
E(B-V) = 0 .064 mag (Schlegel et al.,1998, ApJS, 500, 525).
The photometry is on the UVOT flight systemdescribed in
Poole et al. (2008, MNRAS, 383,627).
GCN Circular 7520
Subject
GRB 080325: GROND Observations
Date
2008-03-25T22:56:25Z (17 years ago)
From
Christian Clemens at MPE <cclemens@mpe.mpg.de>
C. Clemens, A. Kupcu Yoldas, J. Greiner, A. Yoldas, T. Kruehler and G. Szokoly
(Eoetvoes Univ., Budapest and MPE Garching) (all others MPE Garching) report
on behalf of the GROND team:
We observed the field of GRB 080325 (Swift trigger 307604; L. Vetere et al.,
GCN #7512) simultaneously in g', r', i', z', J, H and K with GROND (Greiner
et al. 2008, PASP) mounted at the 2.2m ESO/MPI telescope at La Silla
Observatory (Chile).
Observations started at 09:50 UT on March 25th, 2008, about 5.7 hrs after the
GRB trigger. We obtained 20 mins of total integration time in J, H and K
during morning twilight.
We do not detect any new source within the 2.6'' enhanced Swift-XRT error
circle reported by J. Osborne et al. (GCN #7513) to the following 3-sigma
upper limits:
J > 20.4, H > 19.4 and K > 19.0.
We also detect the afterglow candidate, about 6" south of the centre of the
enhanced Swift-XRT error circle, reported by A. Updike et al. (GCN #7515) to
following magnitude:
J = 18.60 +/- 0.06,
calibrated against 2MASS catalogue stars.
GCN Circular 7521
Subject
GRB080325: XRT Refined Analysis
Date
2008-03-25T23:24:28Z (17 years ago)
From
Loredana Vetere at PSU <vetere@astro.psu.edu>
L. Vetere, J. L. Racusin (PSU) report on behalf of the Swift-XRT team:
We have analysed the first 8 orbits of Swift-XRT data obtained for BAT GRB
080325 (trigger 307604, Vetere et al., GCN Circ. 7512).
The data consist of 360 s in Windowed Timing (WT) mode, starting 160 s after the
BAT trigger and 7.8 ks in Photon Counting (PC) mode. The astrometrically
corrected X-ray position is given in Osborne et al. GCN 7513.
The early WT light-curve shows flaring activity followed by a fast decay that
can be fit by a power law with a slope of alpha1=5.7 � 0.5. The following PC
light curve starts at 3.6 ks after BAT trigger and shows a much slower decay
with a slope of alpha2=0.8 � 0.2. If the light-curve continues to decay at the
same rate, we predict an XRT count rate of 0.011 count/s at T+24 hours.
The spectrum formed from all the WT data can be modeled with a power-law of
photon index Gamma = 2.4 � 0.1, with an absorbing column of NH = (3.0 � 0.1)e21
cm^-2, significantly in excess with respect to the Galactic value of 3.81e20
cm^-2.
This circular is an official product of the Swift-XRT team.
GCN Circular 7522
Subject
GRB 080325: MITSuME Akeno optical upper limits
Date
2008-03-26T07:40:25Z (17 years ago)
From
Nobuyuki Kawai at Tokyo Tech <nkawai@hp.phys.titech.ac.jp>
Y. Kudou, T. Shimokawabe and N. Kawai (Tokyo Tech) report on behalf of
the MITSuME collaboration:
We observed the error box of GRB 080325 (L. Vetere et al. GCN 7512)
with the 3-color 50cm MITSuME Telescope at Akeno, Japan starting
at 16:51:16 Mar 25 UT, 12.7 hr after the trigger under a poor sky
condition at a low altitude.
In the co-added images of Ic, Rc, and g' bands, we did not detect
any afterglow candidate in the XRT error circle.
The 3-sigma limiting magnitudes based on USNO-B1.0 (I-band) and NOMAD
(R-band,g'-band) stars are following.
Filter start time end time Exposure Mag (3-sigma upper limit)
-----------------------------------------------------------------
g' 16:51:16 17:54:41 15 x 60 s 17.2
Rc 16:51:16 17:54:41 15 x 60 s 16.4
Ic 16:51:16 17:54:41 15 x 60 s 17.0
-----------------------------------------------------------------
GCN Circular 7524
Subject
GRB 080325: Subaru detection of NIR afterglow candidate
Date
2008-03-27T06:50:55Z (17 years ago)
From
Nobuyuki Kawai at Tokyo Tech <nkawai@hp.phys.titech.ac.jp>
I. Tanaka, T.-S. Pyo, T. Hattori, K. Aoki (Subaru, NAOJ), C. Tokoku,
T. Yamada (Tohoku U), K. Ohta (Kyoto U), and N. Kawai (Tokyo Tech)
report on behalf of the Subaru GRB team:
We observed the field of GRB 080325 (Vetere et al., GCN 7512) with
MOIRCS on the Subaru Telescope in J and Ks bands starting at 12:51 UT,
March 25, about 8.7 hours after the trigger. The observation lasted
until 15:43 UT with effective exposures of 18 min in J band and 80 min
in Ks band. We detected a faint extended object (Ks=19.5) in the
enhanced Swift XRT error circle (Osborne et al., GCN 7513). We
measure the coordinates of its center as:
18:31:34.24 +36:31:24.3 (J2000, uncertainty 0".3).
There seemed to be a bright spot at the north end of this object.
We performed another set of observation with MOIRCS at March
26.5-26.7 in Ks and J bands. We confirmed that the north spot of the
source had faded significantly, and the total magnitude of the source
had faded by 0.5 mag.
Based on the positional coincidence and the fading behavior, we
suggest that the faint extended source is the host galaxy of GRB
080325, and the spot in the north was the afterglow.
The source 6" south of the enhanced Swift-XRT error circle reported by
Updike et al. (GCN 7515) was also present in our image, and we measure
its magnitude at ~14:00 UT, March 25 (10 hours after the trigger) as:
J = 18.62 +/- 0.03,
consistent with the magnitude reported by Clemens et al. (GCN 7520).
Thus it is not likely to be the afterglow of the GRB.
GCN Circular 7529
Subject
GRB080325 - I and z-band Imaging
Date
2008-03-28T15:27:18Z (17 years ago)
From
Myungshin Im at Seoul Nat U <mim@astro.snu.ac.kr>
M. Im, I. Lee (Seoul National Univ), and Y. Urata (Saitama U/ASIAA)
on behalf of EAFON team.
We took a series of I-band and z-band images of GRB080325,
using the 1.0m telescope at Mt. Lemmon (Arizona, US)
operated by the Korea Astronomy Space Science Institute.
The z-band observation started at March 27, 08:46:06 UT
(2.19223 days after the burst) and the I-band observation
started at March 27, 10:41:05 UT (2.27208 days after the burst).
We do not find an optical counterpart at the location of
the NIR afterglow candidate reported by Tanaka et al. (GCN 7524),
in both I and z-band stacked images.
We set the limit of the GRB afterglow as I > 21.2 mag (3-sigma),
calibrated with a USNO-B star at (18:31:36.3, 36:31:51.0).
The afterglow candidate reported by Updike et al. (GCN 7515)
is detected at both I- and z-bands, with the I-band magnitude
of I=19.0 +- 0.1 mag, calibrated with the same star as above.
However, we note that this object is also visible in the DSS
image (POSS-II), and therefore it is unlikely to be a GRB afterglow.
We thank the LOAO operator, I. Baek for her assistance for this
observation.
GCN Circular 7531
Subject
GRB 080325, Swift-BAT refined analysis
Date
2008-03-28T18:08:58Z (17 years ago)
From
Craig Markwardt at NASA/GSFC/UMD <craigm@milkyway.gsfc.nasa.gov>
E. Fenimore (LANL), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD),
K. McLean (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC),
T. Sakamoto (GSFC/UMBC), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. Ukwatta (GWU), (i.e. the Swift-BAT team), and
L. Vetere (PSU):
Using the data set from T-323 to T+963 sec from all of the telemetry,
we report further analysis of BAT GRB 080325 (trigger #307604)
(Vetere, et al., GCN Circ. 7512). The BAT ground-calculated position
is RA, Dec = 277.906, 36.516 deg which is
RA(J2000) = 18h 31m 37.5s
Dec(J2000) = +36d 30' 57.9"
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 10%.
The mask weighted light curve has a broad FRED-like structure, with
a rise to peak within ~20 sec, followed by a gradual decay extending
out to T+200 sec. The low partial coding in the initial part of the
burst makes it difficult to distinguish between statistical and real
fluctuations. T90 (15-350 keV) is 128.4 +- 34.2 sec (estimated
error including systematics).
The time-averaged spectrum from T-29.3 to T+170.5 sec is best fit by a
simple power-law model. The power law index of the time-averaged
spectrum is 1.68 +- 0.17. The fluence in the 15-150 keV band is
4.9 +- 0.4 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from
T+38.02 sec in the 15-150 keV band is 1.4 +- 0.6 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/307604/BA/
GCN Circular 7563
Subject
GRB 080325: optical upper limit
Date
2008-04-04T15:16:08Z (17 years ago)
From
Graziella Pizzichini at IASF/CNR,Bologna <pizzichini@iasfbo.inaf.it>
F. Munz (INAF/IASF Bologna) F. Terra (Second University of
Rome "Tor Vergata"), G. Greco, C. Bartolini, A. Guarnieri, A. Piccioni
(Bologna University), G. Pizzichini (INAF/IASF Bologna),
D. Nanni (INAF/OAR and Second University of Rome "Tor Vergata"),
M. Redfern (National University of Ireland, Galway), A. De Blasi
(Bologna Observatory) report:
We observed the field of GRB 080325 (GCN 7512, Vetere et al.)
with the 152 cm telescope located in Loiano.
We obtained one 10 min exposure in the Rc filter at mean time
2008 March 26 0.55 UT. Further observations were prevented by
clouds and the moon. We do not detect any object in the Swift-XRT
error box reported by Osborne et al. (GCN 7513).
Our 3-sigma limiting magnitude is R~20.6 (based on Nomad1 catalogue).
The image shall be posted in our public directory
from where it can be retrieved by sftp using
hostname: ermione.bo.astro.it
username: publicGRB
password: GRB_bo
directory: GRB080325