- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Tue 12 Apr 05 05:44:42 UT
NOTICE_TYPE: Swift-BAT GRB Position
TRIGGER_NUM: 114485, Seg_Num: 0
GRB_RA: 181.120d {+12h 04m 29s} (J2000),
181.188d {+12h 04m 45s} (current),
180.480d {+12h 01m 55s} (1950)
GRB_DEC: -1.252d {-01d 15' 07"} (J2000),
-1.282d {-01d 16' 53"} (current),
-0.974d {-00d 58' 25"} (1950)
GRB_ERROR: 4.00 [arcmin radius, statistical only]
GRB_INTEN: 9336 [cnts] Peak=329 [cnts/sec]
TRIGGER_DUR: 2.048 [sec]
TRIGGER_INDEX: 486 E_range: 50-350 keV
BKG_INTEN: 87180 [cnts]
BKG_TIME: 20608.00 SOD {05:43:28.00} UT
BKG_DUR: 24 [sec]
GRB_DATE: 13472 TJD; 102 DOY; 05/04/12
GRB_TIME: 20642.89 SOD {05:44:02.89} UT
GRB_PHI: 126.46 [deg]
GRB_THETA: 12.15 [deg]
SOLN_STATUS: 0x3
RATE_SIGNIF: 18.57 [sigma]
IMAGE_SIGNIF: 9.00 [sigma]
MERIT_PARAMS: +1 +0 +0 +3 +3 +9 +0 +0 +93 +1
SUN_POSTN: 20.74d {+01h 22m 57s} +8.73d {+08d 43' 38"}
SUN_DIST: 159.16 [deg]
MOON_POSTN: 60.92d {+04h 03m 40s} +24.34d {+24d 20' 18"}
MOON_DIST: 117.93 [deg]
MOON_ILLUM: 12 [%]
GAL_COORDS: 279.34, 59.45 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 181.53, -0.70 [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.
- red DSS finding chart
ps-file
- GCN/SWIFT NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Tue 12 Apr 05 05:45:50 UT
NOTICE_TYPE: Swift-XRT Nack-Position
TRIGGER_NUM: 114485, Seg_Num: 0
POINT_RA: 181.096d {+12h 04m 23s} (J2000)
POINT_DEC: -1.249d {-01d 14' 54"} (J2000)
GRB_DATE: 13472 TJD; 102 DOY; 05/04/12
GRB_TIME: 20742.24 SOD {05:45:42.24} UT
COUNTS: 7 Min_needed= 20
STD_DEV: 0.00 Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER: 1 Max_iter_allowed= 4
ERROR_CODE: 1
COMMENTS: SWIFT-XRT Nack Position.
COMMENTS: No source found in the image.
- GCN/SWIFT NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Tue 12 Apr 05 05:48:20 UT
NOTICE_TYPE: Swift-BAT GRB Lightcurve
TRIGGER_NUM: 114485, Seg_Num: 0
GRB_RA: 181.120d {+12h 04m 29s} (J2000),
181.188d {+12h 04m 45s} (current),
180.480d {+12h 01m 55s} (1950)
GRB_DEC: -1.252d {-01d 15' 07"} (J2000),
-1.282d {-01d 16' 53"} (current),
-0.974d {-00d 58' 25"} (1950)
GRB_DATE: 13472 TJD; 102 DOY; 05/04/12
GRB_TIME: 20642.89 SOD {05:44:02.89} UT
TRIGGER_INDEX: 486
GRB_PHI: 126.46 [deg]
GRB_THETA: 12.15 [deg]
DELTA_TIME: 65459.00 [sec]
LC_URL: sw00114485000msb.lc
SUN_POSTN: 20.74d {+01h 22m 57s} +8.73d {+08d 43' 38"}
SUN_DIST: 159.16 [deg]
MOON_POSTN: 60.92d {+04h 03m 40s} +24.34d {+24d 20' 18"}
MOON_DIST: 117.93 [deg]
MOON_ILLUM: 12 [%]
GAL_COORDS: 279.34, 59.45 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 181.53, -0.70 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-BAT GRB Lightcurve.
COMMENTS: This does not match any source in the ground catalog.
- GCN/SWIFT NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Tue 12 Apr 05 05:49:00 UT
NOTICE_TYPE: Swift-XRT Lightcurve
TRIGGER_NUM: 114485, Seg_Num: 0
POINT_RA: 181.097d {+12h 04m 23s} (J2000)
POINT_DEC: -1.248d {-01d 14' 50"} (J2000)
LC_START_DATE: 13472 TJD; 102 DOY; 05/04/12
LC_START_TIME: 20744.92 SOD {05:45:44.92} UT
LC_STOP_DATE: 13472 TJD; 102 DOY; 05/04/12
LC_STOP_TIME: 20922.86 SOD {05:48:42.86} UT
LC_LIVE_TIME: 127.51 [sec], 71.7%
DELTA_TIME: 86222.06 [sec]
N_BINS: 100
TERM_COND: 0
LC_URL: sw00114485000msx.lc
SUN_POSTN: 20.74d {+01h 22m 58s} +8.73d {+08d 43' 39"}
SUN_DIST: 159.14 [deg]
MOON_POSTN: 60.93d {+04h 03m 44s} +24.34d {+24d 20' 32"}
MOON_DIST: 117.89 [deg]
MOON_ILLUM: 12 [%]
GAL_COORDS: 279.30, 59.45 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 181.50, -0.71 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-XRT Lightcurve.
- GCN notice #3235
J. S. Bloom (UCB) and C. Blake (CfA) reports on behalf of a larger
collaboration:
"We begin imaging the field of GRB 050412 (Swift Trigger #114485) with
the PAIRITEL 1.3m at Mt. Hopkins at 2005-04-12 05:48:37 UTC, about 2m55sec
after the GRB trigger. There are no new sources in the error circle to
2MASS detection levels. Further observations and anaylses are ongoing."
This message may be cited.
- GCN notice #3236
S. Covino, S. Piranomonte, P. D'Avanzo, F.M. Zerbi, G. Chincarini, M.
Rodono', G. Tosti, L.A. Antonelli, P. Conconi, G. Cutispoto, E.
Molinari, L. Nicastro, E. Palazzi, E. Meurs, P. Goldoni, on behalf of
the REM/ROSS Team
The REM telescope at the La Silla Observatory (ESO) is observing the
field of GRB 050412. Observations began 34 sec after the alert (39 sec
after the burst).
Preliminary analysis of the first frames reveal no new sources in the
error circle approximately down to the 2MASS limit in the H band and
down to R = 18 in the optical.
Observations and further analyses are going on.
This message may be cited,
- GCN notice #3237
J. Cummings (GSFC/NRC), L. Barbier, S. Barthelmy (GSFC),
E. Fenimore (LANL), M. Galassi (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. Tripicco (GSFC-SSAI), J. Tueller (GSFC), D. Burrows (PSU),
J. Kennea (PSU), V. Mangano (IASF-CNR)
on behalf of the Swift team:
At 05:44:03 UT, Swift-BAT triggered on burst GRB 050412
(trigger=114485) and began to slew 35 seconds after the trigger.
The BAT onboard position is RA, Dec = 181.120, -1.252 (J2000)
with an estimated error of <4 arcminutes. The lightcurve shows
a complex multi-peaked emission from 9 seconds before the
trigger to at least 15 seconds after. There was strong flux in
all energy bands from 15 to 350 keV. The 1 second peak count
rate is 0.8 ph/cm2/s (15-350 keV).
We note that this burst is well suited for ground-based
followup, being anti-Sunward, far from the Moon, away from
the Galactic plane, and equatorial.
No object was detected by the XRT on-board software, beginning
at about T+100 seconds. However, the XRT counting rate is
slightly elevated, indicating a possible weak counterpart.
Further information from all 3 Swift instruments will be
available when data from the Malindi ground station are
received and processed at about 11:00 UT.
- GCN notice #3238
R. M. Quimby (UTexas), E. S. Rykoff (UMich) and B. E. Schaefer (LSU)
report on behalf of the ROTSE collaboration:
ROTSE-IIIb, located at McDonald Observatory, Texas responded automatically
to Swift GRB050412 (Trigger #114485), producing images beginning 7.1
seconds after receiving the GCN trigger under excellent conditions. The
first image was taken at 05:44:48.0 UT, 45.1 seconds after the burst. We
have taken ten 5 second, ten 20 second and forty 60 s exposures and
imaging is ongoing. The images are unfiltered and were calibrated
relative to USNO A2.0.
Individual images have limiting magnitudes ranging from 17.5-19.1.
Comparison to DSS (second epoch) reveals no new sources within the 3-sigma
BAT error circle to a limiting magnitude of 17.5 for the first 5 second
exposure. Coadding the images into sets of 10 revels no new sources down
to 19.1, 19.9 (beginning 05:45:52.1), and 20.3 (beginning 05:50:43.4)
magnitude. Analysis is ongoing.
- GCN notice #3239
Edo Berger (Carnegie Observatories), Nidia Morrell (LCO), Brian Schmidt
(RSAA, ANU), Derek Fox (Caltech), and Paul Price (IfA, Hawaii) report on
behalf of a larger collaboration:
"Starting on 2005, April 12.267 UT (41 min after the burst) we imaged the
BAT error circle of GRB 050412 (GCN 3237) with the DuPont 100-inch
telescope at LCO in the R-band. Two 10-minute images were obtained. A
comparison to DSS reveals no new sources to the limit of the survey
(R~20.5 mag). Furthermore, no sources exhibit a clear fading behavior
between the two images to a limit of R~20.5 mag and delta-R~0.2 mag."
- GCN notice #3240
M.Cwiok, K.Krupska, K.Kwiecinska, L.Mankiewicz, K.Nawrocki,
B.Pilecki, L.W.Piotrowski, M.Sokolowski, D.Szczygiel, G.Wrochna,
on behalf of "Pi of the Sky" collaboration
http://grb.fuw.edu.pl
The GRB 050412 (GCN 3237) error box was observed by "Pi of the Sky"
apparatus at Las Campanas Observatory for most of the night.
No new object has been found within the Swift-BAT error box
before, during or after the GRB. The limiting magnitude
on single exposures (10s) and sums of 20 images is 11m and 11.5m
respectively (unfiltered).
- GCN notice #3241
F. Tamburelli, P. Giommi, M. Capalbi, M. Perri (ASDC), J. Kennea, D. N.
Burrows, J. A. Nousek, M. Chester (PSU), V. Mangano, T. Mineo (IASF/Palermo),
A. F. Abbey, P. T. O'Brien (U. Leicester), A. Moretti, G. Tagliaferri (OAB),
L. Angelini, F. Marshall, and N. Gehrels (NASA/GSFC) report on behalf of the
Swift XRT team:
The Swift BAT instrument detected a GRB at 05:44:03 UT on 12th April 2005
(GCN Circ 3237). The observatory executed an automated slew to the BAT
position and the XRT began taking data at 05:45:42 UT. The XRT was in
Auto state but was not able to centroid on the afterglow due to low source
brightness. From downlinked data we find a uncataloged X-ray source
located at:
RA(J2000) = 12:04:25.3,
Dec(J2000) = -1:12:02.2.
We estimate an uncertainty of about 5 arcseconds radius (90% containment).
This position is 191 arcseconds from the BAT position reported in GCN
3237.
- GCN notice #3242
S. Bradley Cenko and Derek B. Fox (Caltech) report on behalf of the
Caltech-NRAO-Carnegie GRB Collaboration:
We have imaged the field of GRB050412 with the automated Palomar 60-inch
telescope. Observations began approximately 6 minutes after the burst.
Our early time images consist of 3 x 60 second exposures each in the
Kron R (mean epoch 5:57 UT, t ~ 13 minutes after the burst) and Gunn i
(6:02 UT) and z (6:12 UT) bands. We find no sources in the XRT error
circle reported in GCN 3241. Our limiting magnitude, estimated by
comparison with several stars from the Guide Star Catalog, is
approximately R < 20.0
- GCN notice #3243
GRB 050412: Optical observations
Brian L. Jensen, Javier Gorosabel, Peter Laursen, Pall Jakobsson,
Darach Watson, Johan P. U. Fynbo, Jens Hjorth (Niels Bohr Institute)
report:
"Using DFOSC on the Danish 1.5m Telescope on La Silla we have obtained
2550s R-band imaging of the BAT error circle for GRB 050412 (GCN #3237)
starting at 1.2 hr after the GRB trigger. In the XRT error-circle (GCN
#3241) we detect a single source. The estimated magnitude of this source
at t+1.5h is R ~ 22."
- GCN notice #3244
Derek B. Fox (Caltech), S. Bradley Cenko (Caltech), Edo Berger
(Carnegie Observatories), and Nidia Morrell (LCO) report on behalf of
a larger collaboration:
"Examination of our images (GCN 3239) of the GRB 050412 localization
region (GCN 3237) reveals a single optical source proximate to the XRT
position (GCN 3241). Its coordinates are:
RA 12:04:25.0, Dec -01:12:04 (J2000)
by reference to USNO B-1.0 catalog astrometry. Due to saturation of
bright stars in our images and the faintness of the source, we are not
able to perform very accurate photometry at this time; we estimate it
to have R >~ 21.5 mag at 55 minutes after the burst.
If this source is the one referred to by Jensen et al. (GCN 3243), it
is not clear that the source is brighter in our images."
- GCN notice #3245
K. Torii (Osaka U.) reports
"The error region of GRB 050412 (Cummings, et al. GCN 3237) was
observed with the 0.3-m telescope in the New Mexico Skies observatory.
Imaging through clear filter started at 05:48:13 UT (250-s after trigger)
and 10 frames of 120-s exposure were obtained.
We do not find an optical counterpart to the X-ray source
(Tamburelli, et al. GCN 3241) and derive its 3-sigma upper limit
relative to USNO-A2.0 (R) mag as follows.
MeanEpoch Magnitude Exposure
05:49:13 >18.9 120s
06:00:31 >20.5 10x120s
- GCN notice #3247
D. Pooley (UCB) and J. S. Bloom report:
"Inspection of the Swift UVOT Quicklook for GRB 050412 reveals a rapidly
fading source at position:
12:04:31.5
-01:11:53.8
(J2000).
This is not in the XRT error box. Further astrometric and photometric
calibrations are ongoing. For reference, there is a nearby source (with
the current astrometric solution from the Quicklook) at:
12:04:27.
-01:11:19.2
See http://birrung.mit.edu/dave/GRB050412
This message may be cited.
- GCN notice #3248
D. Pooley (UCB) and J. S. Bloom report:
"Upon further inspection of the Swift UVOT Quicklook for GRB 050412 we
cannot confirm the reality of the transient reported in the previous
circular (GCN #3247)."
This message may be cited.
- GCN notice #3249
P. Roming (PSU), V. Mangano (INAF-IASF/Palermo), S. T. Holland (GSFC-USRA),
W. Landsman (GSFC), P. Schady (PSU & MSSL), D. Hinshaw (GSFC-SPSYS), S.
Kobayashi (PSU), A. Blustin (MSSL), N. Gehrels (GSFC), K. Mason (MSSL), J.
Nousek (PSU), and A. Wells (Leicester) on behalf
of the Swift UVOT team report:
The Swift Ultraviolet/Optical Telescope (UVOT) observed the field of GRB
050412 (Cummings et al., GCN 3237) starting at 05:45:40 UT on 12 April
2005. We find no evidence for a source in the 5 arcsecond radius XRT error
circle (Tamburelli et al., GCN 3241) in the UVOT data. The 3-sigma
limiting magnitudes in a 3.5 arcsecond radius circular aperture is V = 19.1
with a systematic uncertainty of 0.1 mag due to uncertainty in the
preliminary flight photometric zero point.
- GCN notice #3250
Brian P Schmidt (Australian National University) and Matthew Whiting
(UNSW) report on behalf of a larger collaboration:
"We observed a 6' region covering the XRT position of the SWIFT burst
GRB 050412 (GCN#3237)
using the ANU 2.3m telescope on April 12.27 UT in R band. The object
located within the XRT error circle (GCN#3241) located at RA
12:04:25.0, Dec -01:12:04 J2000, (GCN#3241, GCN#3243), in comparison
with the images of Berger et al (GCN#3239), is detected at poor SNR at
approximately the same brightness. Neither set of images shows the UVOT
transient object reported by Pooley and Bloom (GCN#3247) to at least
R=21mag."
- GCN notice #3251
J. Tueller, L. Barbier, S. Barthelmy (GSFC), J. Cummings (GSFC/NRC),
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.)
on behalf of the Swift/BAT team:
At 05:44:03 UT Swift-BAT detected GRB 050412 (trigger=114485)
(GCN Circ 3237, Cummings et al.). The refined BAT ground position
is (RA,Dec) = 181.089, -1.206, [deg; J2000] +- 3 arcmin, (95%
containment). This is 1.0 arc minutes from the position determined
by the XRT (GCN Circ 3241, Tamburelli et al.) and the LCO (GCN Circ
3244, Fox et al.)
Examination of the mask weighted light curve shows a 16-second main
peak, starting ~8 seconds before the trigger and having a roughly
symmetrical shape. This is followed by smaller secondary peaks
lasting until ~24 seconds after the trigger. The estimated T90
(15-350 keV) is 26 seconds +/- 2 secs (estimated error including
systematics).
Analysis of the event data shows that this is a very hard burst with
significant emission throughout the BAT energy range (15-350 keV).
The time-averaged total spectrum is consistent with a simple power-law,
with a photon index of -0.62 +/- 0.18 (90% confidence). However,
there may be significant systematic uncertainties with such a
hard spectrum. The photon index of the 5-s peak spectrum (starting at
T0-0.784 s) (also simple power-law) is -0.47 +/- 0.23 (90% confidence).
The fluence derived from the event data is 2.1 (+/- 0.5) X 10^-6 erg/cm^2
in the 15-350 keV band and 9.6 (+/- 1.1) X 10^-7 erg/cm^2 in the
15-200 keV band. The 5-s peak flux is 0.7 +/- 0.1 ph/cm^2/s (15-350 keV).
- GCN notice #3252
Y. Qiu, C.L Lu (BAO), Y.Q. Lou(THCA), K.Y. Huang, W.H. Ip(NCU),
Y. Urata (RIKEN) on EAFON report
" We have observed the XRT error region of GRB 050412 (Tamburelli et
al. GCN 3241) using 0.8-m telescope at XingLong Observatory,
China. Eight R-band images with each 300 exposure times are taken from
15.93 UT to 16.55 UT (~ 10.20 hrs to 10.82 hrs after the burst).
Coadding the eight images yields the 3-sigma limiting magnitude of
R~20, which was calibrated relative to USNO-B1.0 catalog. No new
source was detected in our images. There is no optical emission from
the optical candidate reported by Fox et al. (GCCN 3244) down to the
limiting magnitude."
This message may be cited.
- GCN notice #3253
V. Mangano (IASF/Palermo), M. Capalbi (ASDC), C. Pagani (INAF-OAB), M. Goad
(U. Leicester), J. Kennea and D. Burrows (PSU) report on behalf of the
Swift XRT team:
We have analyzed the Swift XRT data from the first orbit observation of GRB
050412 (Tamburelli et al., GCN3241). The new refined coordinates are:
RA(J2000) = 12h 04m 25.5s
Dec(J2000) = -01:12:00.2
This position is 65.6 arcseconds from the refined BAT position given in GCN
3251 (Tueller et al. 2005) and 3.6 arcsec from the preliminary XRT position
(GCN3241). We estimate an uncertainty of 5 arcseconds radius (90% containment).
The [0.2-10] keV light curve in Windowed Timing (WT) and Photon Counting
(PC) mode starts ~100 seconds from the BAT trigger (T0). We clearly detect
a rapidly fading source.
A preliminary spectral fit to the WT data gives a spectral power law photon
index of 1.35 +/- 0.2 in the [0.5-10] keV band, assuming Galactic
absorption (2.21E20cm^-2). The average (~10000 seconds from trigger)
estimated unabsorbed 0.5-10 keV flux is then about 3.9E-12 erg cm^-2 s^-1.
- GCN notice #3255
M. Jelinek, A. de Ugarte Postigo, V. Casanova,
J. Gorosabel and A. J. Castro-Tirado (IAA-CSIC, Granada)
report:
Following the detection by SWIFT of GRB 050412 (Cummings
et al. GCN Circ. 3237) we have observed the error box
with the 1.5m IAA's telescope at Observatorio de Sierra
Nevada in southern Spain. We have obtained 28 x 120s
images in the R-band under good seeing conditions (1.3")
starting on 12.833 Apr (i.e. 14.55 hr after the event).
We confirm the presence of an object mentioned by
Jensen et al. (GCN Circ. 3243) and Fox et al. (GCN Circ.
3244) at coordinates:
RA: 12:04:25.06 DEC: -01:12:03.6 (J2000).
Expected astrometric uncertainty is 0.5". We find a
preliminary magnitude of the object to be R = 22.75
+/- 0.14 compared to USNO-A2 stars, implying that the
object has not faded in brightness significantly, i.e.
it might be unrelated to GRB 050412. We also notice
that it is 9" from the SWIFT/XRT error box (5" error
radius) provided by Mangano et al.(GCN Circ.3253)."
This message can be quoted.
- GCN notice #3256
W. Li, R. Chornock, S. Jha, and A. V. Filippenko (University of
California, Berkeley) report:
"The Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory
robotically observed Swift GRB 050412 (Trigger #114485; Cummings et
al., GCN 3237). The first 3x15s grid image started at 05:45:09.0 UT
(66s after the burst), but it was not useful due to a technical
problem. Subsequent images have varying exposure times from 15s to
360s, and were observed with R, I, V, and z filters. Within the refined
XRT error circle (Mangano et al., GCN 3253) we did not detect any sources.
Our first useful 15s R-band exposure started at 05:45:53 UT (110s after
the burst) has a limiting magnitude of 17.5 when compared to the USNO
A2.0 caltalog. A 360s R-band exposure started at 06:12:02 UT has a
limiting magnitude of 19.6.
One of us (WL) also took two R-band images with the 1.0-m Nickel
telescope at Lick Observatory: one 1200s exposure started at 07:56:49
UT and the other 600s exposure started at 08:18:03 UT. The combined
image did not detect a source within the XRT error circle to a limiting
mag of about 21. "
- GCN notice #3257
W. Li, R. Chornock, S. Jha, and A. V. Filippenko (University of
California, Berkeley) report:
"The Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory
robotically observed Swift GRB 050412 (Trigger #114485; Cummings et
al., GCN 3237). The first 3x15s grid image started at 05:45:09.0 UT
(66s after the burst), but it was not useful due to a technical
problem. Subsequent images have varying exposure times from 15s to
360s, and were observed with R, I, V, and z filters. Within the refined
XRT error circle (Mangano et al., GCN 3253) we did not detect any sources.
Our first useful 15s R-band exposure started at 05:45:53 UT (110s after
the burst) has a limiting magnitude of 17.5 when compared to the USNO
A2.0 caltalog. A 360s R-band exposure started at 06:12:02 UT has a
limiting magnitude of 19.6.
One of us (WL) also took two R-band images with the 1.0-m Nickel
telescope at Lick Observatory: one 1200s exposure started at 07:56:49
UT and the other 600s exposure started at 08:18:03 UT. The combined
image did not detect a source within the XRT error circle to a limiting
mag of about 21. "
- GCN notice #3259
M. Nysewander, D. Reichart, J. A. Crain report on behalf of the UNC team of
the FUN GRB Collaboration:
We observed the BAT localization of GRB 050412 (Cummings et al., GCN 3237)
with PROMPT beginning 5m 50s after the burst.
We do not detect a source within the XRT localization (Tamburelli et al.,
GCN 3241; Mangano et al. GCN 3253) nor the source identified by Jensen et
al. (GCN 3243).
3-sigma limiting magnitudes are based on 10 USNO-B1.0 stars for Rc and Ic
observations, and 10 NOMAD stars for V observations:
Start Time Integration Filter Limiting Telescope
Since GRB Time Magnitude
5m 50s 10 x 10s Rc 18.5 PROMPT-5
8m 48s 10 x 10s Ic 18.0 PROMPT-5
+ 1 x 20s
14m 30s 1 x 30s Rc 17.9 PROMPT-5
15m 46s 3 x 30s V 20.0 PROMPT-5
+ 10 x 60s
39m 44s 10 x 60s Rc 20.3 PROMPT-5
50m 42s 10 x 60s Ic 18.9 PROMPT-5
61m 46s 10 x 60s V 19.2 PROMPT-5
73m 22s 10 x 60s Rc 20.0 PROMPT-5
84m 29s 10 x 60s Ic 18.3 PROMPT-5
95m 24s 30 x 60s Rc 17.6 PROMPT-5
PROMPT is still being built and commissioned.
- GCN notice #3260
M. Nysewander, D. Reichart, J. A. Crain report on behalf of the UNC team of
the FUN GRB Collaboration:
We observed the BAT localization of GRB 050412 (Cummings et al., GCN 3237)
with PROMPT beginning 5m 50s after the burst.
We do not detect a source within the XRT localization (Tamburelli et al.,
GCN 3241; Mangano et al. GCN 3253) nor the source identified by Jensen et
al. (GCN 3243).
3-sigma limiting magnitudes are based on 10 USNO-B1.0 stars for Rc and Ic
observations, and 10 NOMAD stars for V observations:
Start Time Integration Filter Limiting Telescope
Since GRB Time Magnitude
5m 50s 10 x 10s Rc 18.5 PROMPT-5
8m 48s 10 x 10s Ic 18.0 PROMPT-5
+ 1 x 20s
14m 30s 1 x 30s Rc 17.9 PROMPT-5
15m 46s 3 x 30s V 20.0 PROMPT-5
+ 10 x 60s
39m 44s 10 x 60s Rc 20.3 PROMPT-5
50m 42s 10 x 60s Ic 18.9 PROMPT-5
61m 46s 10 x 60s V 19.2 PROMPT-5
73m 22s 10 x 60s Rc 20.0 PROMPT-5
84m 29s 10 x 60s Ic 18.3 PROMPT-5
95m 24s 30 x 60s Rc 17.6 PROMPT-5
PROMPT is still being built and commissioned.
- GCN notice #3263
G. Kosugi, N. Kawai, K. Aoki, T. Hattori, K. Ohta, and T. Yamada
report on behalf of the Subaru GRB team:
"We have observed the Swift/XRT position of GRB 050412 reported by
Mangano et al.(GCN #3253) in Rc-band with FOCAS on the Subaru 8.2m
telescope atop Mauna Kea on the night of Apr.12. We obtained one 60s
image at 08:03 UT (2.3 hr after the event) and three 600s images at
12:55 UT (7.2 hr after the event).
Our first image shows no afterglow candidates inside the XRT error
circle (5" in radius) down to Rc=24.9 (3-sigma). A galaxy 9" SW from
the XRT position first mentioned by Jensen et al. (GCN #3243) is found
to be Rc=22.6 +/- 0.1.
Our second data set revealed an object almost at the center of the XRT
error circle with the magnitude of Rc=26.0 +/- 0.5. Due to the
marginal detection, we cannot determine whether it is a point source
or a galaxy."
This message may be cited.
- GCN notice #3277
A. M. Soderberg (Caltech) reports on behalf of the
Caltech-NRAO-Carnegie GRB collaboration:
"Using the Very Large Array at 8.5 GHz, we observed the
field of GRB050412 (GCN 3237) on 2005 Apr 16.12 UT.
We do not detect a radio source coincident with the
Swift XRT position (GCN 3253). We place a 2-sigma upper
limit of 38 uJy on the XRT error region.
Further observations are planned."
- GCN notice #3291
E. Berger (Carnegie Observatories) and D. B. Fox (Caltech) report:
"We observed the position of GRB 050412 (GCN 3237) with the Chandra X-ray
Observatory + ACIS for 20 ksec beginning on 2005 April 17.392 UT. A
comprehensive "wavdetect" analysis reveals no X-ray sources in the XRT
5-arcsec error circle (GCN 3253). The 90%-confidence upper limit is 5
counts, or 2.5e-4 counts/sec. Assuming a photon index of 1.35 as inferred
from the XRT data, and a Galactic column density of 2.2e20 cm^-2, we
estimate that the upper limit on the unabsorbed 0.5-10 keV flux is 3.6e-15
erg/cm^2/sec. A comparison to the 0.5-10 keV flux measured by the XRT at
0.116 days after the burst indicates an average fading rate steeper than
alpha=-1.8, suggestive of a jet break between the two observations."
We are grateful to the Chandra Science Data Center for providing rapid
data processsing of this observation, and we thank Harvey Tananbaum for
his allocation of Director's Discretion Time.
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