- GCN/BACODINE POSITION NOTICE
TITLE: GCN/HETE BURST POSITION NOTICE
NOTICE_DATE: Sun 11 Dec 05 02:52:22 UT
NOTICE_TYPE: HETE S/C_Alert
TRIGGER_NUM: 3979, Seq_Num: 1
GRB_DATE: 13715 TJD; 345 DOY; 05/12/11
GRB_TIME: 10205.36 SOD {02:50:05.36} UT
TRIGGER_SOURCE: Trigger on the 25-400 keV band.
GAMMA_RATE: 225 [cnts/s] on a 0.160 [sec] timescale
SC_-Z_RA: 107 [deg]
SC_-Z_DEC: 22 [deg]
SC_LONG: 324 [deg East]
WXM_CNTR_RA: 102.451d {+06h 49m 48s} (J2000),
102.544d {+06h 50m 11s} (current),
101.674d {+06h 46m 42s} (1950)
WXM_CNTR_DEC: +26.599d {+26d 35' 57"} (J2000),
+26.592d {+26d 35' 31"} (current),
+26.657d {+26d 39' 26"} (1950)
WXM_MAX_SIZE: 60.00 [arcmin] diameter
WXM_LOC_SN: 5 sig/noise (pt src in image)
WXM_IMAGE_SN: X= 5.0 Y= 2.5 [sig/noise]
WXM_LC_SN: X= 5.0 Y= 2.2 [sig/noise]
SUN_POSTN: 258.21d {+17h 12m 51s} -23.00d {-22d 59' 43"}
SUN_DIST: 157.66 [deg]
MOON_POSTN: 21.73d {+01h 26m 55s} +10.34d {+10d 20' 35"}
MOON_DIST: 77.25 [deg]
MOON_ILLUM: 79 [%]
GAL_COORDS: 188.76,11.45 [deg] galactic lon,lat of the burst
ECL_COORDS: 101.14,3.64 [deg] ecliptic lon,lat of the burst
COMMENTS: Probable GRB.
COMMENTS: WXM error box is circular; not rectangular.
- red DSS finding chart
ps-file
- GCN NOTICE
TITLE: GCN/HETE BURST POSITION NOTICE
NOTICE_DATE: Sun 11 Dec 05 02:52:53 UT
NOTICE_TYPE: HETE S/C_Update
TRIGGER_NUM: 3979, Seq_Num: 2
GRB_DATE: 13715 TJD; 345 DOY; 05/12/11
GRB_TIME: 10205.36 SOD {02:50:05.36} UT
TRIGGER_SOURCE: Trigger on the 25-400 keV band.
GAMMA_RATE: 225 [cnts/s] on a 0.160 [sec] timescale
SC_-Z_RA: 107 [deg]
SC_-Z_DEC: 22 [deg]
SC_LONG: 324 [deg East]
WXM_CNTR_RA: 102.451d {+06h 49m 48s} (J2000),
102.544d {+06h 50m 11s} (current),
101.674d {+06h 46m 42s} (1950)
WXM_CNTR_DEC: +26.599d {+26d 35' 57"} (J2000),
+26.592d {+26d 35' 31"} (current),
+26.657d {+26d 39' 26"} (1950)
WXM_MAX_SIZE: 60.00 [arcmin] diameter
WXM_LOC_SN: 5 sig/noise (pt src in image)
WXM_IMAGE_SN: X= 5.0 Y= 2.5 [sig/noise]
WXM_LC_SN: X= 5.0 Y= 2.2 [sig/noise]
SUN_POSTN: 258.21d {+17h 12m 51s} -23.00d {-22d 59' 43"}
SUN_DIST: 157.66 [deg]
MOON_POSTN: 21.73d {+01h 26m 56s} +10.35d {+10d 20' 43"}
MOON_DIST: 77.24 [deg]
MOON_ILLUM: 79 [%]
GAL_COORDS: 188.76,11.45 [deg] galactic lon,lat of the burst
ECL_COORDS: 101.14,3.64 [deg] ecliptic lon,lat of the burst
COMMENTS: Probable GRB.
COMMENTS: WXM error box is circular; not rectangular.
- GCN NOTICE
TITLE: GCN/HETE BURST POSITION NOTICE
NOTICE_DATE: Sun 11 Dec 05 02:53:30 UT
NOTICE_TYPE: HETE S/C_Last
TRIGGER_NUM: 3979, Seq_Num: 3
GRB_DATE: 13715 TJD; 345 DOY; 05/12/11
GRB_TIME: 10205.36 SOD {02:50:05.36} UT
TRIGGER_SOURCE: Trigger on the 25-400 keV band.
GAMMA_RATE: 225 [cnts/s] on a 0.160 [sec] timescale
SC_-Z_RA: 107 [deg]
SC_-Z_DEC: 22 [deg]
SC_LONG: 324 [deg East]
WXM_CNTR_RA: 102.451d {+06h 49m 48s} (J2000),
102.544d {+06h 50m 11s} (current),
101.674d {+06h 46m 42s} (1950)
WXM_CNTR_DEC: +26.599d {+26d 35' 57"} (J2000),
+26.592d {+26d 35' 31"} (current),
+26.657d {+26d 39' 26"} (1950)
WXM_MAX_SIZE: 60.00 [arcmin] diameter
WXM_LOC_SN: 5 sig/noise (pt src in image)
WXM_IMAGE_SN: X= 5.0 Y= 2.5 [sig/noise]
WXM_LC_SN: X= 5.0 Y= 2.2 [sig/noise]
SUN_POSTN: 258.21d {+17h 12m 51s} -23.00d {-22d 59' 44"}
SUN_DIST: 157.66 [deg]
MOON_POSTN: 21.74d {+01h 26m 57s} +10.35d {+10d 20' 52"}
MOON_DIST: 77.24 [deg]
MOON_ILLUM: 79 [%]
GAL_COORDS: 188.76,11.45 [deg] galactic lon,lat of the burst
ECL_COORDS: 101.14,3.64 [deg] ecliptic lon,lat of the burst
COMMENTS: Probable GRB.
COMMENTS: WXM error box is circular; not rectangular.
- GCN NOTICE
TITLE: GCN/HETE BURST POSITION NOTICE
NOTICE_DATE: Sun 11 Dec 05 05:58:30 UT
NOTICE_TYPE: HETE Ground Analysis
TRIGGER_NUM: 3979, Seq_Num: 4
GRB_DATE: 13715 TJD; 345 DOY; 05/12/11
GRB_TIME: 10205.36 SOD {02:50:05.36} UT
TRIGGER_SOURCE: Trigger on the 25-400 keV band.
GAMMA_RATE: 0 [cnts/s] on a 0.000 [sec] timescale
SC_-Z_RA: 107 [deg]
SC_-Z_DEC: 22 [deg]
SC_LONG: 324 [deg East]
SXC_CNTR_RA: 104.054d {+06h 56m 13s} (J2000),
104.151d {+06h 56m 36s} (current),
103.240d {+06h 52m 58s} (1950)
SXC_CNTR_DEC: +32.679d {+32d 40' 44"} (J2000),
+32.671d {+32d 40' 15"} (current),
+32.745d {+32d 44' 41"} (1950)
SXC_MAX_SIZE: 2.67 [arcmin] diameter
SXC_LOC_SN: 9 sig/noise (pt src in image)
SUN_POSTN: 258.35d {+17h 13m 25s} -23.01d {-23d 00' 21"}
SUN_DIST: 155.31 [deg]
MOON_POSTN: 23.32d {+01h 33m 18s} +11.13d {+11d 07' 47"}
MOON_DIST: 76.36 [deg]
MOON_ILLUM: 80 [%]
GAL_COORDS: 183.62,15.18 [deg] galactic lon,lat of the burst
ECL_COORDS: 101.97,9.82 [deg] ecliptic lon,lat of the burst
COMMENTS: Definite GRB.
COMMENTS: SXC error box is circular; not rectangular.
COMMENTS: Burst_Validity flag is true.
COMMENTS: SXC data refined since S/C_Last Notice.
- GCN Circular #4324
J-L. Atteia, H. Clergeot, G. Ricker, N. Kawai, D. Lamb, and S. Woosley,
on behalf of the HETE Science Team;
M. Arimoto, T. Donaghy, E. Fenimore, M. Galassi, C. Graziani,
N. Ishikawa, A. Kobayashi, J. Kotoku, M. Maetou, M. Matsuoka,
Y. Nakagawa, T. Sakamoto, R. Sato, T. Shimokawabe, Y. Shirasaki,
S. Sugita, M. Suzuki, T. Tamagawa, K. Tanaka, and A. Yoshida, on behalf
of the HETE WXM Team;
N. Butler, G. Crew, J. Doty, G. Prigozhin, R. Vanderspek,
J. Villasenor, J. G. Jernigan, A. Levine, G. Azzibrouck, J. Braga,
R. Manchanda, G. Pizzichini, and S. Gunasekera, on behalf of the HETE
Operations and HETE Optical-SXC Teams;
M. Boer, J-F Olive, J-P Dezalay, and K. Hurley, on behalf of the HETE
FREGATE Team;
report:
At 02:50:05.4 UTC (10205.4 UT) on 11 December 2005 the HETE FREGATE, WXM,
and SXC instruments detected GRB 051211(=H3979), a GRB.
The flight location was distributed in a GCN Notice at 02:52:22 UTC.
Ground analysis showed that the flight X-location derived from the X
detector is correct but that the Y-location derived from the Y detector
is unreliable, due to the low signal-to-noise of the burst in the Y
detector. As a result, we believe that the flight location distributed
in the GCN Notice is incorrect.
Ground analysis of WXM data yields several possible Y locations. One of
these locations corresponds to a location found through analysis of the
SXC data corresponding to much softer emission about 35s after the
trigger. This may represent soft emission following the hard peak that
triggered HETE. This SXC location was distributed in a GCN Notice at
05:58:30 UT. The location is:
R.A. = 06h 56m 13s ; Dec. = 32d 40' 44" (J2000),
with a 90% confidence error radius of 80".
We caution that while this is our best estimate of the burst location,
under the circumstances we cannot be absolutely certain that this location
is correct.
Further analyses are in progress. Further information about this burst
will be available at the following URL:
http://space.mit.edu/HETE/Bursts/GRB051211
- GCN Circular #4325
A. de Ugarte Postigo (IAA-CSIC Granada), S. Fern=E1ndez-Acosta
(IAC Tenerife), S. Guziy, M. Jel=EDnek, S. B. Pandey,
J. Gorosabel and A. J. Castro-Tirado (IAA-CSIC)
report:
"We have imaged a 7' x 7' region centred on the HETE-2/SXC
error box for GRB 051211 (Atteia et al. GCNC 4324) with the
0.8-m IAC telescope at the Observatorio del Teide starting
on Dec 11.279 UT (i.e. 3.9 hours after the GRB). Two frames
(600s exposure time, R-band) were taken under poor meteo-
rological conditions (strong wind and increasing background
due to the proximity of the twilight). No optical variable
is detected in a 3' field centred on the HETE-2/SXC error
box down to limiting magnitude of R about 19."
This message can be quoted.
- GCN Circular #4326
G. Cusumano (INAF-IASF), D.N. Burrows, S. Hunsberger, C. Pagani (PSU), V.
La Parola, and V. Mangano (INAF-IASF) report on behalf of the Swift XRT team:
The Swift XRT began observing HETE-discovered GRB 051211 (Atteia et al.,
GCN 4324) at 14:43:21 UT on 11 December 2005. In the first two orbits we
accumulated 3330 s of exposure time. We find no X-ray counterpart within
the HETE/SXC error circle, with a 3 sigma upper limit of 3.19E-3
counts/s (2.0 E-13 erg/s/cm/cm). We note that this is considerably
fainter than the typical Swift afterglow at this same time frame, though
not inconsistent with the fainter Swift afterglows (Nousek et al. 2005,
astroph/0508332). Observations will be terminated at about 19:30 UT on 11
December to prevent overheating of the XRT detector.
- GCN Circular #4329
Klotz, A. (CESR-OMP), Boer M. (OHP), and Atteia, J.L. (LAT-OMP) report:
We imaged the entire field of GRB 051211 (H3979) detected by HETE-2
(Atteia et al. GCNC 4324) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France. Observations started 8.1
seconds after the GCN notice (and 3.14 hours after the GRB). The field
had an elevation of 33 degrees above horizon at the begining of the
observations and then decreased.
Two images of 90s were co-added. We compared the 3 arcmin field
centred on the HETE-2/SXC error box with stars of the USNO-B1
catalog. No new source appears brighter than R=15.3.
This message can be cited.
- GCN Circular #4333
M. Jel=EDnek, A. J. Castro-Tirado, S. Vitek, A. de Ugarte Postigo=20
(IAA-CSIC Granada),
P. Kub=E1nek and R. Hudec (Astronomical Institute of the Academy of=20
Sciences, Ondrejov), report:
The BOOTES instruments in South Spain responded to the two GRBs detected =
on
11 Nov 2005. The BOOTES-2 very wide field camera located at La Mayora=20
(EELM-CSIC, M=E1laga) observed the region of the sky containing the=20
HETE-2/SXC
error box for GRB 051211A (Atteia et al. GCN 4324) as part of the=20
routinary observing schedule. A 30s exposure started at 2:50:00 UT (5s=20
prior to the beginning of the 33s
long burst), i.e. overlaping with the single, hard gamma-ray peak=20
detected by HETE-2. This image sets a R =3D 10 upper limit to the promt=20
optical flash for GRB 051211A.
BOOTES-1 in El Arenosillo (INTA, Huelva), responded under non-optimal=20
conditions to the GRB 051211B trigger (Mereghetti et al. GCNC 4327). A=20
sequence of exposures started at 22:06:34 UT (50s after the GRB onset,=20
30s after the GCN notice), i.e. overlaping for 30 s with the tail of the=20
gamma-ray emission. We do no detect any transient optical emission in=20
the 2' INTEGRAL error box and in particular at the position of the=20
possible afterglow reported by Klotz et al. (GCNC 4328). We set a I > 14=20
limit to any optical emission arising simultaneusly to the gamma-rays.=20
We also notice moderate extinction in the line of sight: E(B-V) =3D 0.47=20
from the Schlegel et al. dust maps (1998)."
This message can be quoted.
- GCN Circular #4335
A. de Ugarte Postigo (IAA-CSIC Granada), S. Fern=E1ndez-Acosta
(IAC Tenerife), S. Guziy, M. Jel=EDnek, S. B. Pandey,=20
J. Gorosabel and A. J. Castro-Tirado (IAA-CSIC)
report:
"We have imaged a 7' x 7' region centred on the HETE-2/SXC
error box for GRB 051211 (Atteia et al. GCNC 4324) with the=20
0.8-m IAC telescope at the Observatorio del Teide starting=20
on Dec 11.279 UT (i.e. 3.9 hours after the GRB). Two frames=20
(600s exposure time, R-band) were taken under poor meteo-
rological conditions (strong wind and increasing background
due to the proximity of the twilight). No optical variable=20
is detected in a 3' field centred on the HETE-2/SXC error=20
box down to limiting magnitude of R about 19."
This message can be quoted.
- GCN Circular #4339
S.Maeno,E.Sonoda,M.Yamauchi
(University of Miyazaki)
"We have observed the field covering the error circle of
GRB 051211A (GCN 3979) with the unfiltered CCD camera
on the 30-cm telescope at University of Miyazaki.
The observation was started 11:06:34 UT on Dec.11.
After co-adding a set of 18 images (11:06:34 UT - 11:28:23 UT)
of 30 sec exposures, we have compared with the USNO-A2.0 catalog.
Preliminary analysis shows there is no new source brighter than
17.2 mag."
- GCN Circular #4342
A. J. Blustin (UCL-MSSL), G. Cusumano (INAF-IASF), J. Greiner (MPE),
D. Hinshaw (GSFC-SPSYS), N. Gehrels (GSFC) on behalf of the
Swift/UVOT team
The Swift/UVOT began observing the field of GRB 051211a at 15:50:04 UT
on 2005-12-11, 13 hours after the HETE trigger (Atteia et al., GCN 4324).
No potential optical/UV counterpart was found in co-added images in any
of the filters, within the reported 80 arcsec radius (90% confidence)
HETE error circle, down to the following 5-sigma magnitude upper limits
(not corrected for extinction).
Filter T_range(hours) Exp(s) 5sigUL(mag)
V 14.9-15.1 886 19.4
B 13.5-13.7 738 20.2
U 13.3-16.7 1469 20.3
W1 13.0-16.5 1800 20.0
M2 11.9-15.3 1502 20.1
W2 14.6-14.9 900 20.1
- GCN Circular #4344
R. Zhuchkov, I. Bikmaev, N. Sakhibullin (KSU/AST)
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI)
I. Khamitov, Z. Aslan (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.),
report:
The error radius of GRB 051211a (Atteia et al, GCN4324) was observed with
Russian-Turkish 1.5-m telescope (RTT150, Bakyrlytepe, TUBITAK National Observatory,
Turkey), starting at Dec. 11, 18:38UT, i.e. ~15.8 hours after the burst.
Two frames (300s exposures in R and B bands) were taken. We did not detect
new sources to compare with DSS frames. Using USNO-B1 stars we estimate limiting
magnitude of our images as:
t-t0 Band m_lim
(hour) (mag)
----------------------
15.84 R 20.60
15.99 B 20.57
This message may be cited.
- GCN Circular #4356
C. Guidorzi, A. Monfardini, I.A. Steele, A. Gomboc, C.G. Mundell,
C.J. Mottram, R.J. Smith, D. Bersier, A. Melandri, S. Kobayashi,
D. Carter, M.F. Bode (Liverpool JMU), N. Tanvir (Hertfordshire)
report:
"The 2-m Faulkes Telescope North observed GRB051211A discovered by
HETE-2 (Atteia et al, GCN 4324) from 5.9 to 11.9 hours after the
burst.
So far, searches for afterglow have provided just upper limits in the
optical (de Ugarte Postigo et al. GCN 4325 & GCN 4335, Klotz et al. GCN
4329, Jelinek et al. GCN 4333, Maeno et al. GCN 4339, Blustin et al. GCN
4342, Zhuchkov et al. GCN 4344) as well as in the X-rays (Cusumano et al.
GCN 4326).
From the comparison of two 30-min stacked images, we found an object at
RA=06:56:09.0, DEC= +32:40:06.4 (J2000) showing some evidence of a fading
of 0.6 +- 0.3 mag (calibrated with USNOB stars of the field, with an
uncertainty of 0.4 mag affecting just the absolute values, but not the
relative ones). It lies 63 arcsec away from the HETE-2 centroid (given
with an error radius of 80 arcsec at 90% CL).
-----------------------------------------------------
Start Time Filter Exposure Mag
since GRB
6.3 hr R 12x150s 21.15 +- 0.15
11.4 hr R 12x150s 21.75 +- 0.20
-----------------------------------------------------
This candidate does not match any DSS source, although we notice a small
blur in the DSS IR that might be either a faint source or a background
fluctuation.
If we assume the fading is genuine, the average temporal decay
power-law index turns out to be around 1.0 +- 0.5.
However, a word of caution is required, as the source magnitude is
close to the limiting value affected by the moonlight.
An image of the OT candidate at both epochs is available at the following:
http://www.astro.livjm.ac.uk/~crg/GRB051211A_possible_OT_FTN.jpg
We encourage further observations."
- GCN Circular #4359
N. Kawai, G. Ricker, J-L. Atteia, D. Lamb, and S. Woosley, on behalf of
the HETE Science Team;
M. Arimoto, T. Donaghy, E. Fenimore, M. Galassi, C. Graziani,
N. Ishikawa, A. Kobayashi, J. Kotoku, M. Maetou, M. Matsuoka,
Y. Nakagawa, T. Sakamoto, R. Sato, T. Shimokawabe, Y. Shirasaki,
S. Sugita, M. Suzuki, T. Tamagawa, K. Tanaka, and A. Yoshida, on behalf
of the HETE WXM Team;
N. Butler, G. Crew, J. Doty, G. Prigozhin, R. Vanderspek,
J. Villasenor, J. G. Jernigan, A. Levine, G. Azzibrouck, J. Braga,
R. Manchanda, G. Pizzichini, and S. Gunasekera, on behalf of the HETE
Operations and HETE Optical-SXC Teams;
M. Boer, J-F Olive, J-P Dezalay, and K. Hurley, on behalf of the HETE
FREGATE Team;
report:
We have analyzed the full FREGATE+WXM+SXC data for HETE trigger H3979
(GRB051211A).
Further ground analysis shows that the HETE SXC location for GRB051211A
reported in GCN 4324 is reliable. The SXC detected a soft transient source
in both the its X and Y cameras about 35 s after the trigger without the
assistance of the WXM. The location of this source is:
R.A. = 06h 56m 13s ; Dec. = 32d 40' 44" (J2000),
with a 90% confidence error radius of 80".
The WXM did not detect this soft transient, but it detected hard x-ray
emission coincident with the Fregate event. From this hard emission, WXM
obtained a solid X location matching the SXC transient. There are several
possible WXM Y locations, but one of them matches the SXC transient: the
random probability of this is only a few percent. This triple coincidence
in time and position gives us high confidence that the SXC transient is
associated with the Fregate trigger.
The 30-400 keV light curve has a fast rise (<0.1 s) and a slower
decay. The burst had a T90 duration of 4.8s in the 6-40 keV band, and of
4.2s in the 30-400 keV band.
The integrated spectrum is well-fit by a cutoff power-law function. The
best-fit parameters are:
alpha = -0.67 --- 90% confidence interval is [-0.90 -0.38]
Epeak = 137 keV --- 90% confidence interval is [106 , 200]
The 2-30 keV fluence is 1.6e-7 erg/cm2, while the 30-400 keV fluence is
9.6e-7 erg/cm2.
This burst had a hardness ratio (100-300 keV fluence)/(25-100 keV
fluence) of 1.18. This, along with its 4.2 s T90, places it
between the long duration bursts and the short duration bursts
in the hardness ratio-duration diagram. We note, however, that if
lognormal functions are used to describe the long and short burst duration
distributions, this burst appears more likely to belong to the short
class. Thus, a search for a possible associated low redshift host galaxy
would be of interest.
A light curve, hardness ratio-duration diagram, and spectral information
for this event are provided at the following URL:
http://space.mit.edu/HETE/Bursts/GRB051211/
- GCN Circular #4377
GRB 051211A: Evidence This Is a Short Burst from Analysis of Spectral Lag
J. Norris, G. Ricker, J-L. Atteia, N. Kawai, D. Lamb, and S. Woosley, on
behalf of the HETE Science Team;
M. Arimoto, T. Donaghy, E. Fenimore, M. Galassi, C. Graziani,
N. Ishikawa, A. Kobayashi, J. Kotoku, M. Maetou, M. Matsuoka,
Y. Nakagawa, T. Sakamoto, R. Sato, T. Shimokawabe, Y. Shirasaki,
S. Sugita, M. Suzuki, T. Tamagawa, K. Tanaka, and A. Yoshida, on behalf
of the HETE WXM Team;
N. Butler, G. Crew, J. Doty, G. Prigozhin, R. Vanderspek,
J. Villasenor, J. G. Jernigan, A. Levine, G. Azzibrouck, J. Braga,
R. Manchanda, G. Pizzichini, and S. Gunasekera, on behalf of the HETE
Operations and HETE Optical-SXC Teams;
M. Boer, J-F Olive, J-P Dezalay, and K. Hurley, on behalf of the HETE
FREGATE Team;
report:
We have performed an analysis of the spectral lag for GRB 051211A,
using FREGATE data in the 30-85 keV and 85-400 keV energy bands. We
obtain a spectral lag of 0.000 +/- 0.024 seconds. This result provides
strong additional evidence that GRB 051211A is a short burst [Norris,
J. P., Scargle, J. D., and Bonnell, J. T. 2001, in Gamma-Ray Bursts in
the Afterglow Era, ed. E. Costa, F. Frontera, and J. Hjorth (Berlin:
Springer), p. 40; and Norris, J. P., and Bonnell, J. T. 2005, ApJ,
submitted (see, e.g., Figure 3)].
- GCN Circular #4623
J. P. Halpern (Columbia U.) & N. Mirabal (U. Michigan) report on behalf
of the MDM Observatory GRB follow-up team:
"Guidorzi et al. (GCN 4356) reported a possible optical afterglow
for the HETE-2 burst GRB 051211A (Atteia et al., GCN 4324; Kawai
et al., GCN 4359) that faded from R = 21.15+/-0.15 to R = 21.75+/-0.20
between 6.3 hr and 11.4 hr after the burst. As they noted that there
is a hint of its presence on the I-band POSS plate, and in view of
the likelihood that this was a short burst (Norris et al., GCN 4377),
it is interesting to follow up on this candidate afterglow to determine
if it is hosted by a relatively nearby galaxy. We observed and detected
the same object on 2005 Dec. 25 with the MDM 2.4m telescope and RETROCAM
imager in five 300 s exposures in the SDSS r' filter. Its position is
R.A. = 06:56:09.00, Decl. = +32:40:06.3 (J2000), the same as previously
determined. Calibration with Landolt stars yields R = 21.72+/-0.05
(statistical), with an additional systematic uncertainty of 0.1 likely.
This is consistent with the later measurement of Guidorzi et al.,
but not their earlier one. The object is not resolved in our images
at the seeing of 0.95", which argues against a host interpretation.
We observed it again in the I band with the MDM 8K imager on 2006 Jan. 29.
Three 600 s exposures were obtained in seeing of 0.85". Although the
latter images are uncalibrated, the object appears not to have faded,
is still at the limit of the I-band POSS plate, and is still unresolved.
Therefore, we conclude that it is most likely a star and not the
afterglow of GRB 051211A.
The MDM I-band image is posted at
http://www.astro.columbia.edu/~jules/grb/051211a/
This message may be cited"
- astro-ph/0605570 from
22 May 2006
Donaghy: HETE-2 Localizations and Observations of Four Short Gamma-Ray
Bursts: GRBs 010326B, 040802, 051211 and 060121
Here we report the localizations and properties of four short-duration GRBs
localized by the High Energy Transient Explorer 2 satellite (HETE-2): GRBs
010326B, 040802, 051211 and 060121, all of which were detected by the French
Gamma Telescope (Fregate) and localized with the Wide-field X-ray Monitor (WXM)
and/or Soft X-ray Camera (SXC) instruments. We discuss eight possible criteria
for determining whether these GRBs are "short population bursts" (SPBs) or
"long population bursts" (LPBs). These criteria are (1) duration, (2) pulse
widths, (3) spectral hardness, (4) spectral lag, (5) energy Egamma radiated in
gamma rays (or equivalently, the kinetic energy E_KE of the GRB jet), (6)
existence of a long, soft bump following the burst, (7) location of the burst
in the host galaxy, and (8) type of host galaxy. In particular, we have
developed a likelihood method for determining the probability that a burst is
an SPB or a LPB on the basis of its T90 duration alone. A striking feature of
the resulting probability distribution is that the T90 duration at which a
burst has an equal probability of being a SPB or a LPB is T90 = 5 s, not T90 =
2 s, as is often used. All four short-duration bursts discussed in detail in
this paper have T90 durations in the Fregate 30-400 keV energy band of 1.90,
2.31, 4.25, and 1.97 sec, respectively, yielding probabilities P(S|T90) = 0.97,
0.91, 0.60, and 0.95 that these bursts are SPBs on the basis of their T90
durations alone. All four bursts also have spectral lags consistent with zero.
These results provide strong evidence that all four GRBs are SPBs.
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