- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Sun 12 Oct 08 13:10:56 UT
NOTICE_TYPE: Swift-BAT GRB Position
TRIGGER_NUM: 331475, Seg_Num: 0
GRB_RA: 30.217d {+02h 00m 52s} (J2000),
30.322d {+02h 01m 17s} (current),
29.621d {+01h 58m 29s} (1950)
GRB_DEC: -17.641d {-17d 38' 28"} (J2000),
-17.599d {-17d 35' 56"} (current),
-17.883d {-17d 52' 57"} (1950)
GRB_ERROR: 3.00 [arcmin radius, statistical only]
GRB_INTEN: 9806 [cnts] Image_Peak=232 [image_cnts]
TRIGGER_DUR: 2.048 [sec]
TRIGGER_INDEX: 263 E_range: 25-100 keV
BKG_INTEN: 96789 [cnts]
BKG_TIME: 47388.83 SOD {13:09:48.83} UT
BKG_DUR: 24 [sec]
GRB_DATE: 14751 TJD; 286 DOY; 08/10/12
GRB_TIME: 47423.90 SOD {13:10:23.90} UT
GRB_PHI: 69.75 [deg]
GRB_THETA: 33.55 [deg]
SOLN_STATUS: 0x3
RATE_SIGNIF: 17.60 [sigma]
IMAGE_SIGNIF: 7.78 [sigma]
MERIT_PARAMS: +1 +0 +0 +2 +2 +8 +0 +0 +88 +0
SUN_POSTN: 198.07d {+13h 12m 18s} -7.66d {-07d 39' 35"}
SUN_DIST: 151.99 [deg] Sun_angle= 11.2 [hr] (West of Sun)
MOON_POSTN: 349.40d {+23h 17m 35s} -1.59d {-01d 35' 19"}
MOON_DIST: 43.26 [deg]
MOON_ILLUM: 93 [%]
GAL_COORDS: 185.91,-71.39 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 21.20,-27.96 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: SWIFT-BAT GRB Coordinates.
COMMENTS: This is a rate trigger.
COMMENTS: A point_source was found.
COMMENTS: This does not match any source in the on-board catalog.
COMMENTS: This does not match any source in the ground catalog.
COMMENTS: This is a GRB.
COMMENTS: This trigger occurred at longitude,latitude = 259.33,6.20 [deg].
- red DSS finding chart
ps-file
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Sun 12 Oct 08 13:14:01 UT
NOTICE_TYPE: Swift-BAT GRB Lightcurve
TRIGGER_NUM: 331475, Seg_Num: 0
GRB_RA: 30.217d {+02h 00m 52s} (J2000),
30.322d {+02h 01m 17s} (current),
29.621d {+01h 58m 29s} (1950)
GRB_DEC: -17.641d {-17d 38' 28"} (J2000),
-17.599d {-17d 35' 56"} (current),
-17.883d {-17d 52' 57"} (1950)
GRB_DATE: 14751 TJD; 286 DOY; 08/10/12
GRB_TIME: 47423.90 SOD {13:10:23.90} UT
TRIGGER_INDEX: 263
GRB_PHI: 69.75 [deg]
GRB_THETA: 33.55 [deg]
DELTA_TIME: 12.00 [sec]
TRIGGER_DUR: 2.048 [sec]
SOLN_STATUS: 0x3
RATE_SIGNIF: 17.60 [sigma]
IMAGE_SIGNIF: 7.78 [sigma]
LC_URL: sw00331475000msb.lc
SUN_POSTN: 198.08d {+13h 12m 18s} -7.66d {-07d 39' 38"}
SUN_DIST: 151.99 [deg] Sun_angle= 11.2 [hr] (West of Sun)
MOON_POSTN: 349.42d {+23h 17m 41s} -1.58d {-01d 34' 31"}
MOON_DIST: 43.24 [deg]
MOON_ILLUM: 93 [%]
GAL_COORDS: 185.91,-71.39 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 21.20,-27.96 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: SWIFT-BAT GRB Lightcurve.
COMMENTS:
COMMENTS: The next comments were copied from the BAT_POS Notice:
COMMENTS: This is a rate trigger.
COMMENTS: A point_source was found.
COMMENTS: This does not match any source in the on-board catalog.
COMMENTS: This does not match any source in the ground catalog.
COMMENTS: This is a GRB.
COMMENTS: This trigger occurred at longitude,latitude = 259.33,6.20 [deg].
- GCN Circular #8361
M. C. Stroh (PSU), W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU),
P. A. Evans (U Leicester), D. Grupe (PSU),
S. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU),
J. A. Kennea (PSU), D. M. Palmer (LANL), D. Perez (U Leicester),
J. L. Racusin (PSU), T. Sakamoto (NASA/UMBC),
T. N. Ukwatta (GSFC/GWU), L. Vetere (PSU) and H. Ziaeepour (UCL-MSSL)
report on behalf of the Swift Team:
At 13:10:23 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 081012 (trigger=331475). Swift did not immediately slew due to
the Earth limb constraint. The BAT on-board calculated location is
RA, Dec 30.217, -17.641 which is
RA(J2000) = 02h 00m 52s
Dec(J2000) = -17d 38' 28"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a single-peaked
structure with a duration of about 20 sec. The peak count rate
was ~2000 counts/sec (15-350 keV), at ~0 sec after the trigger.
Due to an observing constraint, Swift will not slew until
T0+49.2 minutes. There will be no XRT or UVOT data until
this time.
Burst Advocate for this burst is M. C. Stroh (stroh AT astroh.org).
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 #8362
F. Yuan (U Mich) report on behalf of the ROTSE collaboration:
ROTSE-IIIa, located at Siding Spring Observatory, Australia, responded
to GRB 081012 (Swift trigger 331475, GCN 8361, Stroh et al. ),
producing images beginning 7.2s after the GCN notice time. An
automated response took the first image at 13:11:03.2 UT, 39.3s after
the burst. Early observations were affected by proximity to the full
moon and the first usable image started at 13:27:03.0 UT, ~1000s after
the burst. We took over 100 20s exposures. These unfiltered images are
calibrated relative to USNO A2.0 (R). Imaging is on going.
Comparison to the DSS (second epoch) reveals no new sources within the
3-sigma Swift/BAT error circle, for both single images and coadding
into sets of 10. Individual images have limiting magnitudes ranging
from 15.8-16.2; we set the following specific limits.
start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd?
--------------------------------------------------------------------
13:27:03.0 13:27:23.0 20 15.8 999 N
13:28:01.3 13:32:42.9 281 17.4 1057 Y
- GCN Circular #8363
G. Sato (ISAS), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL),
T. Sakamoto (GSFC/UMBC), M. Stamatikos (GSFC/ORAU), M. C. Stroh (PSU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
Using the data set from T-119 to T+183 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 081012 (trigger #331475)
(Stroh, et al., GCN Circ. 8361). The BAT ground-calculated position is
RA, Dec = 30.184, -17.627 deg which is
RA(J2000) = 02h 00m 44.1s
Dec(J2000) = -17d 37' 36.2"
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 26%.
The mask-weighted light curve shows a roughly symmetrical peak starting
at ~T-20 sec, peaking at ~T+1 sec, and ending at ~T+20 sec. There is
a possibility of earlier emission at ~T-50 sec.
T90 (15-350 keV) is 29 +- 4 sec (estimated error including systematics).
The time-averaged spectrum from T-23.1 to T+8.9 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.03 +- 0.18. The fluence in the 15-150 keV band is 1.1 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+0.93 sec in the 15-150 keV band
is 1.0 +- 0.2 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/331475/BA/
- GCN Circular #8364
J. A. Kennea and M. Stroh (PSU) report on behalf of the Swift/XRT Team
We have analyzed downlinked data from the XRT observations of GRB 081012
(Stroh et al, GCN #8361). The XRT began observing the field at 14:00:09
UT, approximately 49 minutes after the BAT trigger. Data from the first
orbit of observations reveal an uncatalogued point source at RA, Dec =
30.20029, -17.63715 which is the equivalent to:
RA(J2000) = 02h 00m 48.0s
Dec(J2000) = -17d 38m 13.7s
with an estimated uncertainty of 8 arcseconds radius (90% confidence).
This position is 67 arcseconds from the BAT refined position (Sato et
al, GCN #8363).
- GCN Circular #8365
N. P. M. Kuin (MSSL/UCL) and M.C. Stroh (PSU) report on behalf of
the Swift UVOT team.
The Swift UltraViolet/Optical Telescope (UVOT) began observations of
GRB081012 (Swift BAT trigger number 331475, Stroh et al., GCN Circ.
8361), on October 12, 2008, at 14:02:28 ,52 minutes after the
trigger.
We do not detect any new source at the XRT position reported in GCN
Circ. 8364 (Kennea et al.).
The magnitude upper limits for detecting GRB081012 at the XTR position
are given below for the first observations in the UVOT filters:
Filter Tstart(s) Tstop(s) Exp(s) Magnitude
uvw2 3125 3325 196.6 >20.09 (3-sigma UL)
v 3329 3458 125.8 >19.12 (3-sigma UL)
uvm2 4876 5076 196.6 >19.72 (3-sigma UL)
uvw1 5082 5282 196.6 >19.94 (3-sigma UL)
u 5287 5487 196.6 >20.00 (3-sigma UL)
b 5492 5692 196.6 >20.33 (3-sigma UL)
wh 5697 5713 15.7 >19.42 (3-sigma UL)
The values quoted above are on the UVOT Photometric System
(Poole et al, 2008, MNRAS 383,627). They are not corrected for the
expected galactic reddening of E(B-V) = 0.023 in the direction of
the burst (Schlegel et al. 1998).
- GCN Circular #8366
A. de Ugarte Postigo (ESO), D. Malesani (DARK/NBI)
T. Augusteijn (NOT) report on behalf of a larger
collaboration:
We have observed the field of GRB 081012 (Stroh et al.,
GCN 8361) from the 2.5m NOT telescope at Roque de los
Muchachos Observatory. A combination of 6x300s R-band
observations with mean time 23.79 UT (0.44 days after
the burst) did not show any source within the XRT error
box (Kennea & Stroh GCN 8364) down to a 3-sigma
limiting magnitude of R > 22.0. The images were moderately
contaminated by the light of the nearby Moon.
- GCN Circular #8370
E. Bissaldi (MPE) reports on behalf of the Fermi GBM Team:
"At 13:10:23 UT on 12 October 2008, the Fermi Gamma-ray Burst Monitor
triggered and located GRB 081012 (trigger 245509824/081012549), which
was also detected by Swift (Stroh et al., GCN 8361).
The on-ground calculated location, using the Fermi GBM trigger data, is
RA = 30.9, Dec = -19.2 (equivalent to J2000
02h 04m, -19d 12'), with a statistical uncertainty of 6.8 degrees
(radius, 1-sigma containment; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
This position is 1.7 deg from the Swift XRT position
(Kennea et al., GCN 8364). The angle from the Fermi LAT boresight
to the Swift position is 61 degrees.
GRB 081012 is single peaked with an estimated T90 (25-900 keV)
of about 30 s. The time-averaged spectrum from T0-3.1 s to T0+7.2 s
is well fit by a power law function with an exponential
high-energy cutoff. The cutoff energy, parameterized as
Epeak, is 360 +/- 70 keV with a power law index of -0.31 +/- 0.23.
It can also be fit by using a Band function with Epeak = 320 +/- 80 keV
and beta = -2.4 +/- 0.7. However alpha is poorly constrained.
The fluence (25-900 keV) for the power law model with
exponential cutoff is (3.8 +/- 0.4)E-06 erg/cm2.
The 1 sec peak photon flux measured starting from T0+4.1 in
the 25-900 keV band is 2.0 +/- 0.2 ph/s/cm2.
The spectral analysis results presented above are preliminary;
the final results will be published in the Fermi GBM GRB Catalog."
- GCN Circular #8373
R. Filgas, T. Kruehler, J. Greiner, C. Clemens, A. Yoldas (all MPE
Garching), A. Rossi (Tautenburg Obs.), A. Kupcu Yoldas (ESO) and
G. Szokoly (Eoetvoes Univ., Budapest) report on behalf of the GROND team:
GROND (Greiner et al. 2008, PASP 120, 405), mounted at the 2.2m
ESO/MPI telescope at La Silla Observatory (Chile), started
observations of the field of GRB 081012 (Stroh et al. 2008, GCN #8361)
in g'r'i'z'JHK at 07:43 UT on 13. Oct. 2008, 18.5 hours after
the burst. This burst was also detected by the Fermi GBM (Bissaldi
2008, GCN #8370). GROND observations consisted of 20 115-s
integrations in g'r'i'z' and 240 10-s integrations in JHK.
We do not detect a source in the XRT error circle (Kennea & Stroh
2008, GCN #8364) in the stacked images down to limiting magnitudes
(all in Vega system) of
g' > 23.2
r' > 23.5
i' > 22.8
z' > 22.8
J > 21.5
H > 20.4
K > 19.4
The given limits are derived based on calibrating the images
against USNO and 2MASS field stars and are not corrected for the Galactic
foreground extinction corresponding to a reddening of E_(B-V)= 0.023
in the direction of the burst (Schlegel et al. 1998).
- GCN Circular #8391
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester)
report on behalf of the Swift-XRT team:
Using 1387 s of XRT Photon Counting mode data and 2 UVOT images, we find
an astrometrically corrected X-ray position (using the XRT-UVOT alignment
and matching to the USNO-B1 catalogue): RA, Dec = 30.2009, -17.6383 which
is equivalent to:
RA (J2000): 02 00 48.22
Dec (J2000): -17 38 18.0
with an uncertainty of 1.8 arcsec (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 is an offical product of the Swift XRT team.
- GCN Circular #8394
M.C. Stroh and C. Pagani (PSU) report on behalf of the Swift-XRT team:
We have analyzed the Swift-XRT data obtained for GRB 081012 (Stroh et
al., GCN Circ. 8361), totaling 30.4ks of Photon Counting data.
The X-ray light-curve can be fit by a simple power law with a decay
index of 1.49 +/- 0.07.
The spectrum can be fit with an absorbed power-law with absorption
consistent with the Galactic nH value (2.37e20 cm-2, Kalberla et al.
2005) and with a photon index of 1.44 (+0.35/-0.34). The average
observed (unabsorbed) 0.3-10 keV flux is 6.19e-11 (6.40e-11) ergs/cm^2/
s.
This is an official product of the Swift-XRT team.
Previous IAU Circulars 