- GCN/BACODINE POSITION NOTICE
TITLE: GCN/HETE BURST POSITION NOTICE
NOTICE_DATE: Fri 08 Apr 05 16:22:55 UT
NOTICE_TYPE: HETE S/C_Alert
TRIGGER_NUM: 3711, Seq_Num: 1
GRB_DATE: 13468 TJD; 98 DOY; 05/04/08
GRB_TIME: 58970.93 SOD {16:22:50.93} UT
TRIGGER_SOURCE: Trigger on the 6-80 keV band.
GAMMA_RATE: 650 [cnts/s] on a 0.160 [sec] timescale
SC_-Z_RA: 187 [deg]
SC_-Z_DEC: -6 [deg]
SC_LONG: 156 [deg East]
SUN_POSTN: 17.47d {+01h 09m 53s} +7.42d {+07d 24' 55"}
MOON_POSTN: 15.61d {+01h 02m 27s} +6.17d {+06d 10' 15"}
MOON_ILLUM: 0 [%]
COMMENTS: Probable GRB.
- GCN/BACODINE POSITION NOTICE
TITLE: GCN/HETE BURST POSITION NOTICE
NOTICE_DATE: Fri 08 Apr 05 16:23:02 UT
NOTICE_TYPE: HETE S/C_Update
TRIGGER_NUM: 3711, Seq_Num: 2
GRB_DATE: 13468 TJD; 98 DOY; 05/04/08
GRB_TIME: 58970.93 SOD {16:22:50.93} UT
TRIGGER_SOURCE: Trigger on the 6-80 keV band.
GAMMA_RATE: 650 [cnts/s] on a 0.160 [sec] timescale
SC_-Z_RA: 187 [deg]
SC_-Z_DEC: -6 [deg]
SC_LONG: 156 [deg East]
WXM_CNTR_RA: 180.480d {+12h 01m 55s} (J2000),
180.547d {+12h 02m 11s} (current),
179.840d {+11h 59m 21s} (1950)
WXM_CNTR_DEC: +10.844d {+10d 50' 38"} (J2000),
+10.815d {+10d 48' 52"} (current),
+11.122d {+11d 07' 20"} (1950)
WXM_MAX_SIZE: 28.00 [arcmin] diameter
WXM_LOC_SN: 13 sig/noise (pt src in image)
WXM_IMAGE_SN: X= 11.2 Y= 7.5 [sig/noise]
WXM_LC_SN: X= 15.5 Y= 8.7 [sig/noise]
SUN_POSTN: 17.47d {+01h 09m 53s} +7.42d {+07d 24' 55"}
SUN_DIST: 155.18 [deg]
MOON_POSTN: 15.61d {+01h 02m 27s} +6.17d {+06d 10' 15"}
MOON_DIST: 157.34 [deg]
MOON_ILLUM: 0 [%]
GAL_COORDS: 264.98,69.98 [deg] galactic lon,lat of the burst
ECL_COORDS: 176.08,10.13 [deg] ecliptic lon,lat of the burst
COMMENTS: Probable GRB.
COMMENTS: WXM error box is circular; not rectangular.
- GCN/BACODINE POSITION NOTICE
TITLE: GCN/HETE BURST POSITION NOTICE
NOTICE_DATE: Fri 08 Apr 05 16:23:08 UT
NOTICE_TYPE: HETE S/C_Update
TRIGGER_NUM: 3711, Seq_Num: 3
GRB_DATE: 13468 TJD; 98 DOY; 05/04/08
GRB_TIME: 58970.93 SOD {16:22:50.93} UT
TRIGGER_SOURCE: Trigger on the 6-80 keV band.
GAMMA_RATE: 650 [cnts/s] on a 0.160 [sec] timescale
SC_-Z_RA: 187 [deg]
SC_-Z_DEC: -6 [deg]
SC_LONG: 156 [deg East]
WXM_CNTR_RA: 180.482d {+12h 01m 56s} (J2000),
180.549d {+12h 02m 12s} (current),
179.841d {+11h 59m 22s} (1950)
WXM_CNTR_DEC: +10.877d {+10d 52' 38"} (J2000),
+10.848d {+10d 50' 52"} (current),
+11.156d {+11d 09' 20"} (1950)
WXM_MAX_SIZE: 28.00 [arcmin] diameter
WXM_LOC_SN: 21 sig/noise (pt src in image)
WXM_IMAGE_SN: X= 18.0 Y= 11.7 [sig/noise]
WXM_LC_SN: X= 23.0 Y= 13.0 [sig/noise]
SUN_POSTN: 17.47d {+01h 09m 53s} +7.42d {+07d 24' 55"}
SUN_DIST: 155.16 [deg]
MOON_POSTN: 15.61d {+01h 02m 27s} +6.17d {+06d 10' 15"}
MOON_DIST: 157.32 [deg]
MOON_ILLUM: 0 [%]
GAL_COORDS: 264.93,70.01 [deg] galactic lon,lat of the burst
ECL_COORDS: 176.07,10.16 [deg] ecliptic lon,lat of the burst
COMMENTS: Probable GRB.
COMMENTS: WXM error box is circular; not rectangular.
- GCN/BACODINE POSITION NOTICE
TITLE: GCN/HETE BURST POSITION NOTICE
NOTICE_DATE: Fri 08 Apr 05 16:23:13 UT
NOTICE_TYPE: HETE S/C_Update
TRIGGER_NUM: 3711, Seq_Num: 4
GRB_DATE: 13468 TJD; 98 DOY; 05/04/08
GRB_TIME: 58970.93 SOD {16:22:50.93} UT
TRIGGER_SOURCE: Trigger on the 6-80 keV band.
GAMMA_RATE: 650 [cnts/s] on a 0.160 [sec] timescale
SC_-Z_RA: 187 [deg]
SC_-Z_DEC: -6 [deg]
SC_LONG: 156 [deg East]
WXM_CNTR_RA: 180.482d {+12h 01m 56s} (J2000),
180.549d {+12h 02m 12s} (current),
179.841d {+11h 59m 22s} (1950)
WXM_CNTR_DEC: +10.877d {+10d 52' 38"} (J2000),
+10.848d {+10d 50' 52"} (current),
+11.156d {+11d 09' 20"} (1950)
WXM_MAX_SIZE: 28.00 [arcmin] diameter
WXM_LOC_SN: 21 sig/noise (pt src in image)
WXM_IMAGE_SN: X= 18.0 Y= 11.7 [sig/noise]
WXM_LC_SN: X= 23.0 Y= 13.0 [sig/noise]
SXC_CNTR_RA: 180.561d {+12h 02m 15s} (J2000),
180.628d {+12h 02m 31s} (current),
179.921d {+11h 59m 41s} (1950)
SXC_CNTR_DEC: +10.851d {+10d 51' 03"} (J2000),
+10.821d {+10d 49' 17"} (current),
+11.129d {+11d 07' 45"} (1950)
SXC_MAX_SIZE: 5.00 [arcmin] diameter
SXC_LOC_SN: 2 sig/noise (pt src in image)
SUN_POSTN: 17.47d {+01h 09m 53s} +7.42d {+07d 24' 55"}
SUN_DIST: 155.23 [deg]
MOON_POSTN: 15.61d {+01h 02m 27s} +6.17d {+06d 10' 15"}
MOON_DIST: 157.39 [deg]
MOON_ILLUM: 0 [%]
GAL_COORDS: 265.17,70.03 [deg] galactic lon,lat of the burst
ECL_COORDS: 176.15,10.17 [deg] ecliptic lon,lat of the burst
COMMENTS: Probable GRB.
COMMENTS: WXM error box is circular; not rectangular.
COMMENTS: SXC error box is circular; not rectangular.
- GCN/BACODINE POSITION NOTICE
TITLE: GCN/HETE BURST POSITION NOTICE
NOTICE_DATE: Fri 08 Apr 05 16:23:16 UT
NOTICE_TYPE: HETE S/C_Update
TRIGGER_NUM: 3711, Seq_Num: 5
GRB_DATE: 13468 TJD; 98 DOY; 05/04/08
GRB_TIME: 58970.93 SOD {16:22:50.93} UT
TRIGGER_SOURCE: Trigger on the 6-80 keV band.
GAMMA_RATE: 650 [cnts/s] on a 0.160 [sec] timescale
SC_-Z_RA: 187 [deg]
SC_-Z_DEC: -6 [deg]
SC_LONG: 156 [deg East]
WXM_CNTR_RA: 180.481d {+12h 01m 55s} (J2000),
180.548d {+12h 02m 12s} (current),
179.840d {+11h 59m 22s} (1950)
WXM_CNTR_DEC: +10.861d {+10d 51' 38"} (J2000),
+10.831d {+10d 49' 52"} (current),
+11.139d {+11d 08' 20"} (1950)
WXM_MAX_SIZE: 28.00 [arcmin] diameter
WXM_LOC_SN: 31 sig/noise (pt src in image)
WXM_IMAGE_SN: X= 25.5 Y= 17.0 [sig/noise]
WXM_LC_SN: X= 25.5 Y= 18.7 [sig/noise]
SXC_CNTR_RA: 180.561d {+12h 02m 15s} (J2000),
180.628d {+12h 02m 31s} (current),
179.921d {+11h 59m 41s} (1950)
SXC_CNTR_DEC: +10.851d {+10d 51' 03"} (J2000),
+10.821d {+10d 49' 17"} (current),
+11.129d {+11d 07' 45"} (1950)
SXC_MAX_SIZE: 5.00 [arcmin] diameter
SXC_LOC_SN: 2 sig/noise (pt src in image)
SUN_POSTN: 17.47d {+01h 09m 53s} +7.42d {+07d 24' 55"}
SUN_DIST: 155.23 [deg]
MOON_POSTN: 15.61d {+01h 02m 27s} +6.17d {+06d 10' 15"}
MOON_DIST: 157.39 [deg]
MOON_ILLUM: 0 [%]
GAL_COORDS: 265.17,70.03 [deg] galactic lon,lat of the burst
ECL_COORDS: 176.15,10.17 [deg] ecliptic lon,lat of the burst
COMMENTS: Probable GRB.
COMMENTS: WXM error box is circular; not rectangular.
COMMENTS: SXC error box is circular; not rectangular.
- GCN/BACODINE POSITION NOTICE
TITLE: GCN/HETE BURST POSITION NOTICE
NOTICE_DATE: Fri 08 Apr 05 16:23:33 UT
NOTICE_TYPE: HETE S/C_Update
TRIGGER_NUM: 3711, Seq_Num: 6
GRB_DATE: 13468 TJD; 98 DOY; 05/04/08
GRB_TIME: 58970.93 SOD {16:22:50.93} UT
TRIGGER_SOURCE: Trigger on the 6-80 keV band.
GAMMA_RATE: 650 [cnts/s] on a 0.160 [sec] timescale
SC_-Z_RA: 187 [deg]
SC_-Z_DEC: -6 [deg]
SC_LONG: 156 [deg East]
WXM_CNTR_RA: 180.481d {+12h 01m 55s} (J2000),
180.548d {+12h 02m 12s} (current),
179.840d {+11h 59m 22s} (1950)
WXM_CNTR_DEC: +10.861d {+10d 51' 38"} (J2000),
+10.831d {+10d 49' 52"} (current),
+11.139d {+11d 08' 20"} (1950)
WXM_MAX_SIZE: 28.00 [arcmin] diameter
WXM_LOC_SN: 31 sig/noise (pt src in image)
WXM_IMAGE_SN: X= 25.5 Y= 17.0 [sig/noise]
WXM_LC_SN: X= 25.5 Y= 18.7 [sig/noise]
SUN_POSTN: 17.47d {+01h 09m 53s} +7.42d {+07d 24' 55"}
SUN_DIST: 155.17 [deg]
MOON_POSTN: 15.61d {+01h 02m 27s} +6.17d {+06d 10' 15"}
MOON_DIST: 157.33 [deg]
MOON_ILLUM: 0 [%]
GAL_COORDS: 264.96,69.99 [deg] galactic lon,lat of the burst
ECL_COORDS: 176.07,10.15 [deg] ecliptic lon,lat of the burst
COMMENTS: Probable GRB.
COMMENTS: WXM error box is circular; not rectangular.
- GCN/BACODINE POSITION NOTICE
TITLE: GCN/HETE BURST POSITION NOTICE
NOTICE_DATE: Fri 08 Apr 05 16:26:15 UT
NOTICE_TYPE: HETE S/C_Last
TRIGGER_NUM: 3711, Seq_Num: 7
GRB_DATE: 13468 TJD; 98 DOY; 05/04/08
GRB_TIME: 58970.93 SOD {16:22:50.93} UT
TRIGGER_SOURCE: Trigger on the 6-80 keV band.
GAMMA_RATE: 650 [cnts/s] on a 0.160 [sec] timescale
SC_-Z_RA: 187 [deg]
SC_-Z_DEC: -6 [deg]
SC_LONG: 156 [deg East]
WXM_CNTR_RA: 180.481d {+12h 01m 55s} (J2000),
180.548d {+12h 02m 12s} (current),
179.840d {+11h 59m 22s} (1950)
WXM_CNTR_DEC: +10.861d {+10d 51' 38"} (J2000),
+10.831d {+10d 49' 52"} (current),
+11.139d {+11d 08' 20"} (1950)
WXM_MAX_SIZE: 28.00 [arcmin] diameter
WXM_LOC_SN: 31 sig/noise (pt src in image)
WXM_IMAGE_SN: X= 25.5 Y= 17.0 [sig/noise]
WXM_LC_SN: X= 25.5 Y= 18.7 [sig/noise]
SUN_POSTN: 17.47d {+01h 09m 53s} +7.42d {+07d 24' 55"}
SUN_DIST: 155.17 [deg]
MOON_POSTN: 15.61d {+01h 02m 27s} +6.17d {+06d 10' 15"}
MOON_DIST: 157.33 [deg]
MOON_ILLUM: 0 [%]
GAL_COORDS: 264.96,69.99 [deg] galactic lon,lat of the burst
ECL_COORDS: 176.07,10.15 [deg] ecliptic lon,lat of the burst
COMMENTS: Probable GRB.
COMMENTS: WXM error box is circular; not rectangular.
- GCN/BACODINE POSITION NOTICE
TITLE: GCN/HETE BURST POSITION NOTICE
NOTICE_DATE: Fri 08 Apr 05 17:36:02 UT
NOTICE_TYPE: HETE Ground Analysis
TRIGGER_NUM: 3711, Seq_Num: 8
GRB_DATE: 13468 TJD; 98 DOY; 05/04/08
GRB_TIME: 58970.93 SOD {16:22:50.93} UT
TRIGGER_SOURCE: Trigger on the 6-80 keV band.
GAMMA_RATE: 650 [cnts/s] on a 0.160 [sec] timescale
SC_-Z_RA: 186 [deg]
SC_-Z_DEC: -6 [deg]
SC_LONG: 156 [deg East]
SXC_CNTR_RA: 180.563d {+12h 02m 15s} (J2000),
180.630d {+12h 02m 31s} (current),
179.923d {+11h 59m 41s} (1950)
SXC_CNTR_DEC: +10.867d {+10d 52' 01"} (J2000),
+10.838d {+10d 50' 16"} (current),
+11.145d {+11d 08' 43"} (1950)
SXC_MAX_SIZE: 2.67 [arcmin] diameter
SXC_LOC_SN: 11 sig/noise (pt src in image)
SUN_POSTN: 17.47d {+01h 09m 53s} +7.42d {+07d 24' 55"}
SUN_DIST: 155.22 [deg]
MOON_POSTN: 15.61d {+01h 02m 27s} +6.17d {+06d 10' 15"}
MOON_DIST: 157.38 [deg]
MOON_ILLUM: 0 [%]
GAL_COORDS: 265.14,70.04 [deg] galactic lon,lat of the burst
ECL_COORDS: 176.15,10.18 [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.
- red DSS finding chart with 2.67 arcmin diameter error circle
ps-file
- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Fri 08 Apr 05 17:03:14 UT
NOTICE_TYPE: Swift-FOM Will_Observe
TRIGGER_NUM: 20004, Seg_Num: 1
GRB_RA: 180.481d {+12h 01m 55s} (J2000),
180.548d {+12h 02m 12s} (current),
179.841d {+11h 59m 22s} (1950)
GRB_DEC: +10.861d {+10d 51' 40"} (J2000),
+10.832d {+10d 49' 54"} (current),
+11.139d {+11d 08' 22"} (1950)
GRB_DATE: 13468 TJD; 98 DOY; 05/04/08
GRB_TIME: 58971.00 SOD {16:22:51.00} UT
TRIGGER_INDEX: 0
RATE_SIGNIF: 0.00 [sigma]
FLAGS: 0x3
MERIT: 100.00
SUN_POSTN: 17.47d {+01h 09m 53s} +7.42d {+07d 24' 55"}
SUN_DIST: 155.17 [deg]
MOON_POSTN: 15.61d {+01h 02m 27s} +6.17d {+06d 10' 15"}
MOON_DIST: 157.33 [deg]
MOON_ILLUM: 0 [%]
GAL_COORDS: 264.96, 69.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 176.07, 10.15 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT Figure-of-Merit decision.
COMMENTS: This Notice is generated as a result of an uploaded TOO -- this is not a normal BAT-detected burst.
COMMENTS: As a result of this TOO, only the GRB_RA/_DEC fields will be valid!
COMMENTS: This was of sufficient merit to become the new Automated Target;
COMMENTS: but if the Current PPT has a greater merit, then we will not request a slew.
COMMENTS: FOM will request the s/c to slew.
COMMENTS: The S/C has yet to make its decision about safe to slew or not.
COMMENTS: This does not match any source in the ground catalog.
- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Fri 08 Apr 05 17:03:15 UT
NOTICE_TYPE: Swift-S/C Will_Slew
TRIGGER_NUM: 20004, Seg_Num: 1
GRB_RA: 180.481d {+12h 01m 55s} (J2000),
180.548d {+12h 02m 12s} (current),
179.841d {+11h 59m 22s} (1950)
GRB_DEC: +10.861d {+10d 51' 40"} (J2000),
+10.832d {+10d 49' 54"} (current),
+11.139d {+11d 08' 22"} (1950)
GRB_DATE: 13468 TJD; 98 DOY; 05/04/08
GRB_TIME: 58971.00 SOD {16:22:51.00} UT
TRIGGER_INDEX: 0
RATE_SIGNIF: 0.00 [sigma]
SLEW_QUERY: 0x0
WAIT_TIME: 0.00 [sec]
OBS_TIME: 388.00 [sec]
INST_MODES: BAT: 0 XRT: 0 UVOT: 32768
MERIT: 100.00
SUN_POSTN: 17.47d {+01h 09m 53s} +7.42d {+07d 24' 55"}
SUN_DIST: 155.17 [deg]
MOON_POSTN: 15.61d {+01h 02m 27s} +6.17d {+06d 10' 15"}
MOON_DIST: 157.33 [deg]
MOON_ILLUM: 0 [%]
GAL_COORDS: 264.96, 69.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 176.07, 10.15 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT SC Slew decision.
COMMENTS: This Notice is generated as a result of an uploaded TOO -- this is not a normal BAT-detected burst.
COMMENTS: As a result of this TOO, only the GRB_RA/_DEC fields will be valid!
COMMENTS: SC will slew to this target.
COMMENTS: This does not match any source in the ground catalog.
- GCN notice #3188
V. Lipunov, A.Krylov, V.Kornilov, G.Borisov, D.Kuvshinov,
A.Belinski, M.Kuznetsov, S.Potanin, G.Antipov,
E.Gorbovskoy, N.Tyurina
Sternberg Astronomical Institute, Moscow
After HETE alert 3711 MASTER robotic telescope
(http://observ.pereplet.ru)
had imaging the corresponding area of the sky under the bad weather
conditions at 17h21m53.75 UT (1h 09m after GRB Time, OUR SUNSET ).
There are no new object up to 14.7 on unfiltered image of the error box
(30s exposition, 6 square degrees field).
The JPG-images are available at
http://observ.pereplet.ru/images/GRB050408/1.jpg
This is preliminary result.
Observations are continuing.
This message may be cited.
This work is supported by Moscow Union "Optic" and partly supported by
RFFI 04-02-16411.
Mailto: lipunov@sai.msu.ru
- GCN notice #3189
GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
T. Sakamoto, 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,
J. Kotoku, M. Maetou, M. Matsuoka, Y. Nakagawa, R. Sato, Y. Shirasaki,
M. Suzuki, T. Tamagawa, K. Tanaka, Y. Yamamoto, 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, and G. Pizzichini, 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:
The HETE FREGATE, WXM, and SXC instruments detected GRB 050408 (=H3711)
at 16:22:50.93 UT (58970.93 SOD) on 8 April 2005. WXM and SXC flight
localizations were reported in a GCN Notice issued at 16:23:02, which
was 11 sec after the burst trigger and while the burst was still in
progress.
The final WXM and SXC flight localizations were reported in a GCN
Notice issued at 16:23:13 UT. The final WXM flight localization can be
expressed as a circle of 14 arcminutes radius (90% confidence) that is
centered at
WXM-Flight: RA = 12h 01m 55s, DEC = +10d 51' 38" (J2000).
The final SXC flight localization can be expressed as a circle of 150
arcseconds radius that is centered at
SXC-Flight: RA = +12h 02m 15s, DEC = +10d 51' 03" (J2000).
Ground analysis produced an updated SXC localization that was reported
in a GCN Notice issued at 17:36:02. This ground SXC localization can
be expressed as a circle of 80 arcseconds radius that is centered at
SXC-Ground: RA = +12h 02m 15s, DEC = +10d 52' 01" (J2000).
The burst has a duration T_90 of ~34 seconds in 7-40 keV and 7-80 keV,
and T_90 of ~15 seconds in 30-400 keV. Preliminary spectral analyses
show the 2-30 keV fluence of GRB 050408 to be ~1.4 x 10-6 ergs cm-2 and
the 30-400 keV fluence to be ~1.9 x 10-6 ergs cm-2. Therefore
GRB 050408 is an "X-ray-rich" GRB.
A light curve, skymap, and spectral information for GRB 050408 are
provided at the following URL:
http://space.mit.edu/HETE/Bursts/GRB050408
This message may be cited.
- GCN notice #3190
GRB 050408: ROTSE-III Optical Limits
D.A. Smith, S.A. Yost, & E.S. Rykoff (U of Michigan) report on behalf of the
ROTSE collaboration:
ROTSE-IIIa, located at Siding Spring Observatory, Australia, responded to GRB
050408 (HETE trigger 3711). An automated response produced images beginning at
16:23:09.4 UT, 18.5 s after the trigger time and 6.6 s after the alert was
distributed. The first few images were therefore recorded while the burst was
still active at high energies (Sakamoto et al., GCN Circ. #3189). The
telescope took 10 5-sec, 10 20-sec, and a series of 60-sec eposures. These
unfiltered images are calibrated relative to USNO A2.0 (R). The ROTSE-III
images show strong and increasing degredation from clouds. After the 20th
image (~7.7 min after the trigger time), clouds became opaque enough to render
many images useless.
Comparison to the DSS (second epoch) reveals no new sources within the 3-sigma
SXC error circle. Individual images have limiting magnitudes ranging from
14.7-16.9. In particular, we set a limit of magnitude 14.7 in the first 5 s
exposure. Coadding the first ten images yields a limiting magnitude of 15.1,
and coadding the 20-s images (165.5-522.5 s after the trigger time) yields a
limiting magnitude of 17.8.
- GCN notice #3191
A. A. Wells, A. F. Abbey, J. P. Osborne, A. P. Beardmore, (U. Leicester),
J. A. Kennea, M. Chester, D. N. Burrows, J. A. Nousek (PSU), M. Capalbi,
F. Tamburelli (ASDC), P. Romano, C. Pagani, G. Chincarini (INAF-OAB), G.
Cusumano, V. La Parola, (INAF-IASF/Palermo), D. Lamb (U. Chicago), G.
Ricker (MIT) and N. Gehrels (GSFC), report on behalf of the Swift XRT
team:
The Swift XRT observed the field of the HETE burst GRB050408 (Sakamoto
etal. 2005, GCN 3189) at 17:05:18 UT. We find a bright fading uncataloged
X-ray source located at:
RA(J2000) = 12:02:17.4,
Dec(J2000) = +10:51:03
We estimate an uncertainty of about 6 arcseconds. This source is located
78 arcseconds from the HETE SXC-Ground position in GCN 3189.
- GCN notice #3192
A. de Ugarte Postigo (IAA-CSIC Granada), V. Komarova,
T. Fathkullin, T. Sokolova, V. Sokolov, V. Vlasyuk,
Yu. Balega (SAO RAS, Russia), S. Guziy (Univ. of Nikolaev),
M. Jelinek, J. Gorosabel and A.J. Castro-Tirado
(IAA-CSIC Granada),
report:
Following the detection by HETE-2 of the long X-ray gamma-
ray burst GRB 050408 (Sakamoto et al., GCN 3189), we have
taken R-band images at the 1m and 6m telescope at the Special
Astrophysical observatory starting at 20.25 UT (i.e. 3.9 hr
after the event). Within the X-ray error box provided by
SWIFT/XRT (Wells et al. GCN 3191), we identify three
point-like sources. The brightest one (R = 20.5) is at
preliminary coordinates RA(2000) = 12 02 17.32, Dec(2000) =
+10 51 10 (error 1"), which we identify at the potential
GRB 050408 optical afterglow. The object does not appear in
the corresponding DSS-2 plate. Further observations are in
progress.
We thanks the SAO RAS director Yu. Balega for his support
for the SAO RAS GRB ToO programme.
- GCN notice #3193
A. de Ugarte Postigo (IAA-CSIC Granada), V. Komarova,
T. Fathkullin, T. Sokolova, V. Sokolov, V. Vlasyuk,
Yu. Balega (SAO RAS, Russia), S. Guziy (Univ. of Nikolaev),
M. Jelinek, J. Gorosabel and A.J. Castro-Tirado
(IAA-CSIC Granada),
report:
Following the detection by HETE-2 of the long X-ray rich
GRB GRB 050408 (Sakamoto et al., GCN 3189), we have taken
R-band images at the 1m and 6m telescope at the Special
Astrophysical observatory starting at 20.25 UT (i.e. 3.9 hr
after the event). Within the X-ray error box provided by
SWIFT/XRT (Wells et al. GCN 3191), we identify three
point-like sources. The brightest one (R = 20.5) is at
preliminary coordinates RA(2000) = 12 02 17.32, Dec(2000) =
+10 51 10 (error 1"), which we identify at the potential
GRB 050408 optical afterglow. The object does not appear in
the corresponding DSS-2 plate. Further observations are in
progress.
We thanks the SAO RAS director Yu. Balega for his support
for the SAO RAS GRB ToO programme.
- GCN notice #3194
S. Klose, U. Laux, and B. Stecklum, Thüringer Landessternwarte Tautenburg,
J. Greiner, MPE Garching,
report:
Tautenburg started observing the field of GRB 050408 (Sakamoto et al.
2005, GCN 3189) at 19:01 UT on Apr 08. Observations were performed in
V, R, and I, even though the weather conditions were not good.
A first inspection of the R-band images obtained between 19:29 and 19:40
UT does not show a source in the Swift/XRT error circle, implying R>20
about 3 hrs after the burst.
- GCN notice #3195
D. Kuroda (JAXA/ISAS), K. Yanagisawa (OAO), and N. Kawai (Tokyo Tech)
report on behalf of MITSUME collaboration:
"We observed the field covering the entire error circle of GRB050408
(GCN 3189, Sakamoto et al.) with the 50 cm Mitsume Telescope at Okayama,
Japan in V, R, and I bands from 17:49 to 18:32 (UT), and obtained 37
frames of 60 sec exposure.
Comparison of the co-added image to the DSS revealed no new objects
down to a limiting magnitude of R=17.8 as estimated using USNO A2.0
catalog."
- GCN notice #3196
GRB 050408: Optical afterglow confirmed
K.Y. Huang, W.H. Ip, D. Kinoshita (NCU), Y. Urata, T. Tamagawa
(RIKEN), Y. Qiu (BAO) and Y.Q. Lou (THCA) on behalf of the East-Asia
GRB Follow-up Observation Network (EAFON) report:
" We have started the observation for the field of GRB 050408 at 17:10
UT on Apr 08 (55 min after the burst). Using Lulin-One meter Telescope
(LOT), we have performed 'VR broad band' filter imaging
observation. These images show a source in the Swift/XRT error
circle. The coordinate is consistent with that of A. de Ugarte Postigo
et al. (GCN 3193). Based on our preliminary 'VR-band' photometry, the
source shows variability which decay index is about -0.6 between
17:17(UT) and 18:33(UT). This source is therefore likely to be the
optical afterglow of GRB 050408. Further analysis is in progress.
This message may be cited."
- GCN notice #3197
M. Jelinek (IAA-CSIC Granada), T. Fathkullin, V. Komarova,
T. Sokolova, V. Sokolov, V. Vlasyuk, Yu. Balega (SAO RAS,
Russia), S. Guziy (Univ. of Nikolaev), A. de Ugarte Postigo,
J. Gorosabel and A.J. Castro-Tirado (IAA-CSIC Granada),
report:
Further monitoring of the optical source reported by de
Ugarte Postigo et al. (GCNC 3192), confirms a steepening
of the optical decline, when comparing to the Huang et al.
results (GCNC 3196). From the first frame obtained at the 6m
SAO RAS telescope on Apr 8, 18:49 UT (this value supersedes
the one given on GCN 3192) to the last one (at 21:38 UT),
the object has declined significantly, implying a decay
index alpha of -1.6 . An ID-chart is posted at:
http://sirrah.cz/mates/grb050408.jpg
- GCN notice #3198
Z. Aslan,I. Khamitov,T. Ozisik, K. Uluc(TUG), U. Kiziloglu (METU),I.
Bikmaev, R. Gumerov, N. Sakhibullin (KSU/AST), A. Alpar (SabUni), R.
Burenin, M. Pavlinsky, R. Sunyaev (IKI),
report:
We have observed the error box of GRB 050408(GCN 3189 and GCN 3191)
with TFOSC (the imaging and spectroscopic camera of the TUBITAK National
Observatory, Turkey) attached to the Russian-Turkish 1.5-m telescope
(Bakyrlytepe, Turkey). We made series of 30s and 60s exposures in Rc,
starting at 18:46 UT. We have found the OT candidate indicated in GCN 3193
getting fainter with a spectral index of -0.63. We have determined its
postion and magnitudes using USNO-B1. The position and the preliminary R
photometry are as follows:
RA: 12:02:17.31 Dec: +10:51:9.4 (+/- 0.1 arcsec)(2000)
T-T0(hours) Rc
3.7 20.94 +/- 0.1
4.4 21.05
5.4 21.17
6.7 21.31
8.3 21.50
The reductions are in progress.
This message may be cited.
- GCN notice #3199
H.- W. Chen (MIT), Paul J. Green (CfA), J. S. Bloom (UCB), & J. X.
Prochaska (UCSC) report on behalf of the GRAASP collaboration:
"We began imaging the position of GRB050408 at 00:12, April 9 (UT), using
IMACS on the Magellan/Baade telescope in the R and I bands. The afterglow
candidate reported by de Ugarte Postigo et al. (GCN #3193) is detected in
both bandpasses. Based on a comparison with objects found in the 2MASS
catalog, we measured the coordinates of the afterglow as RA(J2000)=
12:02:17.328 and Dec(J2000)=+10:51:09.47 with an error of 250 mas in each
coordinate. We also measure the afterglow brightness to be R = 21.7 +/-
0.1 mag and I = 21.4 +/- 0.1 mag with R-I=0.3, 7h50m after the initial
trigger."
This message may be cited.
- GCN notice #3200
K. Wiersema, P. Curran (University of Amsterdam),
K. Lefever, H. van Winckel, C. Waelkens (Katholieke Universiteit Leuven),
O. van Braam, Y. Grange, R. de Rooij, A. de Vries, L. Waters, (University
of Amsterdam),
report:
"We have taken R- and I-band images of the optical afterglow
reported by de Ugarte Postigo et al. (GCN 3193) of the
HETE-2 GRB 050408 (Sakamoto et al., GCN 3189) at the
1.2m Mercator Telescope at La Palma.
The R-band observation started at 20:56 UT and consisted of
3 x 5m, 1 x 3m and 1 x 8m exposure time, making the
total exposure time 26 minutes, with midpoint 4.82h after burst.
The I-band observation started at 21:30 UT and consisted of
2 x 5 minutes exposure time, with midpoint 5.22h after burst.
We calibrate our photometry using the USNO-B catalogue values.
We find an R-band magnitude of 21.25 +/- 0.2 and a
I-band magnitude of 20.4 +/- 0.3.
We thank the staff of the Mercator Telescope for the
excellent assistance."
- GCN notice #3201
Edo Berger, Mike Gladders, and Gus Oemler (Carnegie Observatories) report:
"On 2005, April 9.22 UT we obtained a spectrum of the optical afterglow
(GCN 3193) of GRB 050408 (GCN 3189) with LDSS-3 on the Magellan/Clay
telescope. We find a broad emission line which we interpret as [OII]3727
at a redshift of z=1.236 and an absorption doublet which we interpret as
MgII 2796/2803 at the same redshift.
Given a fluence of about 3.3e-6 erg/cm^2 the isotropic-equivalent
gamma-ray energy is 1.3e52 erg."
- GCN notice #3202
Kuntal Misra, S. B. Pandey (ARIES Naini Tal) and Atish P. Kamble
(Raman Research Institute, Bangalore) on behalf of larger Indian
GRB collaboration
We acquired V, R, I frames of GRB 050408 error box localized by HETE-II
(GCN 3189) and SWIFT (GCN 3191) around 2 hours after the burst in thin
cloudy conditions. The afterglow candidate by Postigo et al. (GCN 3192)
is seen in our frames. The magnitude of our frame taken around 2.4 hours
after the burst (exp-time 300secx2) is R_c = 20.4 +/- 0.2, calibrated with
respect to USNO B1.0 stars 1008-0199794 (R ~ 16.62) and
1008-0199752 (R ~ 15.89).
Our derived magnitude in combination with the R band magnitudes by
Aslan et al. (GCN 3198) follow the power law decay index of 0.70 +/- 0.06,
consistent to those by Huang et al. (GCN 3196) and Aslan et al. (GCN
3198).
This message can be cited.
- GCN notice #3203
S.Maeno,E.Sonoda,Y.Tokunaga,M.Yamauchi
(University of Miyazaki)
"We have observed the field covering the error circle of
GRB 050408 (GCN 3189;HETE Trigger time is 16:22:50.93 UT)
with the unfiltered CCD camera on the 30-cm telescope
at University of Miyazaki.
The observation was started 16:52:23 UT on Apr.8.
After co-adding a set of 20 images (16:52:23 UT - 17:29:14 UT)
of 30 sec exposures, we have compared with the USNO-A2.0 catalog.
Preliminary analysis shows there is no new source brighter than
17.6 mag. at the reported position by A. de Ugarte Postigo et al.
(GCN3192). "
- GCN notice #3204
Jason X. Prochaska (UCO/Lick Obs.), J. S. Bloom (UCB), H.-W. Chen (MIT),
R. J. Foley (UCB) & K. Roth (Gemini Obs.) report on behalf of the GRAASP
collaboration:
"We acquired a Gemini/GMOS optical spectrum (R~3000) of the afterglow GRB
050408 (GCN #3189) on UT April 9.42. We identify MgI absorption at a
heliocentric redshift of z=1.2357 +/- 0.0002, consistent with the
previously reported value (GCN #3201). In addition we confirm the
presence of a resolved emission doublet consistent with redshifted
[OII]3727. We also report tentative detections of the TiII 3230, 3384
transitions suggesting the gas associated with the host galaxy is
relatively dust poor and/or high in metal content."
We thank the Gemini observing staff for assistance.
- GCN notice #3205
A. Melandri, L. A. Antonelli, S. Covino, V. Testa, A. Monfardini,
E. Palazzi, G. Chincarini, F. M. Zerbi, G. Tosti, E. Molinari,
L. Nicastro, F. Vitali, on behalf of the REM/ROSS team, report:
"On Apr 9, 2005 the REM telescope observed the field of GRB050408
(Sakamoto et al. GCN 3189) from La Silla Observatory (Chile).
The field was imaged with both REM instruments REM-IR and ROSS in
V, R, I, J, H and Ks filters starting at 00:31 UT (approximately 8.2
hours after the burst) for a total integration time of 200 seconds
for each filter.
No sources are detected within SWIFT XRT error circle (Wells et al. GCN
3191) and at the position of the Optical Transient (Ugarte et al., GCN
3192; Huang et al., GCN 3196) down to a limiting magnitude of 18.5,
18.3, 17.9, 16.8, 17.4, 18.4 (5-sigma upper limit)
This message can be cited."
- GCN notice #3206
V.Rumyantsev (CrAO), V.Biryukov (SAI, MSU), and A.Pozanenko (IKI) on behalf
of larger GRB follow up collaboration report:
We have obtained 20 unfiltered images of the GRB050408 (HETE 3711) error box
(Sakamoto et al., GCN 3189). The images were taken with the AT-64 telescope
of Crimean Astrophysical observatory and cover the period UT 18:19:33 -
18:45:57 of April 08, 2005. No source was detected within SWIFT XRT error
box (Wells et al. GCN 3191) and at the position of the optical transient
(Ugarte et al., GCN 3192). Best limiting magnitude of the combined image
(S/N=3) calibrated against R USNO-A2.0 is following
Mid Time(UT) telescope exposure limiting mag.
April 08 18:33 AT-64 20x60 s 19.9
This message can be cited.
- GCN notice #3207
T. Mizuno, Y. Arai, H. Yamagishi (Tokyo Gakugei Univ.),
T. Soyano (Kiso observatory), Y. Urata, T. Tamagawa(RIKEN),
K.Y. Huang(NCU) on behalf of EAFON report,
" We have imaged the entire error region of GRB 050408 (GCN3189) with
1.05m Schmidt telescope at Kiso observatory, Japan in R band.
Utilizing HETE-2 GCN alert, the observation was started at 16:42 UT
(20 min after the burst) and lasted to 1 hour. There is no optical
emission from the optical afterglow (GCN 3192, GCN 3196) down to a
limiting magnitude of R=19.1 as estimated using USNO B1.0 catalog.
This message may be cited."
- GCN notice #3208
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 optical/IR imaging of the error region of GRB 050408
(GCN 3189, Sakamoto et al.) beginning ~10.9 hours post-burst
(2005-04-09 03:14 UT). Total summed exposure times amounted to
36 minutes in I and 30 minutes in J.
The optical afterglow reported by de Ugarte Postigo et al. (GCN 3193)
is detected in both our I and J-band images, though the source appears
only slightly above the background in J. Preliminary comparison
with Landolt standard stars yields an I magnitude of 21.3+/-0.1.
Comparison with IR standard stars LCO-LHS2397a and PERSSON-P9144 yields a
J magnitude of 21.0+/-0.8.
- GCN notice #3209
G. Chincharini, P. Romano, S. Campana, C. Pagani, G. Tagliaferri
(INAF-OAB), M. Capalbi, P. Giommi (ASDC), J. Kennea, D. N. Burrows (PSU),
A. Wells, O. Godet (U. Leicester), G. Cusumano, V. Mangano (IASF/Palermo),
L. Cominsky (Sonoma State U.), K. Hurley (UCB), and N. Gehrels (GSFC),
report on behalf of the Swift XRT team:
We have analyzed the Swift XRT data from GRB 050408 (Sakamoto et al. 2005,
GCN 3189; Wells et al. 2005, GCN 3191) using 8 orbits with a total exposure
time of 6417 s in Photon Counting (PC) mode. The refined coordinates of the
X-ray afterglow are:
RA(J2000) = 12:02:17.5
Dec(J2000) = +10:51:06.5
We estimate an uncertainty of 5 arcseconds radius (90% containment). This
position is 3.9 arcsec from the optical candidates (De Ugarte-Postigo et
al., GCN 3192; Chen et al., GCN 3199).
The [0.2-10] keV light curve in PC mode starts 2555 seconds after the
HETE-II trigger (T0). The count rate is decaying following a power law
with a slope of about 0.8 over a time interval of 40 ks. With the current
data we do not see evidence of a break in the XRT light curve.
A preliminary spectral fit to the PC data gives a power law photon index of
2.2 +/- 0.2 in the [0.5-10] keV band, with a column density of
(2.5+/-0.6)E21 cm^-2 (the Galactic value is 1.8E20 cm^-2). The average
unabsorbed 0.5-10 keV flux is about 6.2E-12 erg
cm^-2 s^-1 (in the time range 2.5-43.5 ks from trigger).
- GCN notice #3210
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 GRB050408 (GCN 3189) on 2005 Apr 9.26 UT.
We do not detect a radio source coincident with the
X-ray or optical afterglow positions (GCNs 3191 and 3192).
We place a 2-sigma limit of 74 uJy at the optical position.
Further observations are planned."
- GCN notice #3211
P. Curran, K. Wiersema (University of Amsterdam), K. Lefever, H. van
Winckel, C. Waelkens (Katholieke Universiteit Leuven), O. van Braam, Y.
Grange, R. de Rooij, A. de Vries, L. Waters, (University of Amsterdam),
G.Bourban, G.Burki, F.Carrier (Geneva Observatory), E. Rol (University of
Leicester)
report:
"On 09 April we continued our observations (GCN 3200) of the
optical afterglow reported by de Ugarte Postigo et al. (GCN 3193) of the
HETE-2 GRB 050408 (Sakamoto et al., GCN 3189) at the 1.2m Mercator
Telescope at La Palma.
The R-band observation started at 05:15 UT and consisted of 2 x 8 minute
exposures, with midpoint 13.02h after burst.
We calibrated our photometry using the USNO-B catalogue.
We find a marginal R-band detection of 22.3 +/- 0.3.
We thank the staff of the Mercator Telescope for the excellent
assistance."
- GCN notice #3212
GRB 050408: Properties of the Host Galaxy
D. Q. Lamb, D. G. York, and D. E. Reichart report:
The field of GRB 050408 (Sakamoto, et al., GCN Circular 3189) has been
observed by the Sloan Digital Sky Survey and the data is publicly
available as part of Data Release 3. Examination of the SDSS image
of the field of GRB 050408 reveals a galaxy at
RA = (180.57109 deg), Dec = (+10.85051 degree),
coincident with the optical afterglow of GRB 050408. The magnitudes
of the galaxy are u = 23.49, g = 23.30, r = 22.37, i = 21.95, and z =
21.39, with errors of +/- 0.01 mag, with the exception of the z band
where the uncertainty is somewhat larger.
These results suggest that light from the host galaxy may contribute
significantly to the optical magnitudes reported for the optical
afterglow of GRB 050408 as early as ~10 hours after the burst. This
implies that continued Swift XRT observations of the X-ray afterglow
of GRB 050408 (e.g., Wells et al., GCN Circular 3191; Chincharini et
al. 3209) may be the only way of determining the light curve, and
therefore the jet break time, for the afterglow of this burst.
This message may be cited.
- GCN notice #3213
M. Nysewander, S. Heathcote (CTIO), D. Reichart, M. Bayliss report on
behalf of the UNC team of the FUN GRB Collaboration:
We observed the afterglow of GRB 050408 (Sakamoto et al., GCN 3189; Wells
et al., GCN 3191; de Ugarte Postigo et al., GCN 3192) with the 4.1-meter
diameter SOAR Telescope at CTIO, using the SOAR Optical Imager.
Beginning 9.3 hours after the burst, we observed for 10 x 200 sec in Rc, 9
x 200 sec in each of V and B, and 9 x 300 sec in U. The afterglow is well
detected in Rc, V, and B.
Between 9.3 and 10.7 hours after the burst, the Rc light curve faded with a
temporal index of -2.23 +/- 0.60. However, between 10.7 and 13.4 hours
after the burst, the temporal index is only -0.54 +/- 0.36. This suggests
that the afterglow was fading rapidly but is now contaminated by a host
galaxy. This confirms the host galaxy identified by Lamb et al. (GCN 3212)
in the SDSS DR3.
We are very grateful to the SOAR staff for supporting these observations
during SOAR's commissioning period.
- GCN notice #3214
T. Tamagawa, Y. Urata (RIKEN), F. Usui (ISAS/JAXA), K. Onda, K. Abe,
M. Tashiro (Saitama-U) on bealf of the WIDGET collaboration
report:
"The very widefield camera, WIDGET, located at Akeno, Japan, observed
the region of HETE-2 error box for GRB 050408 (GCN 3189, Sakamoto et
al.). We continuously monitored the HETE-2 field-of-view with repeat
of unfiltered 5 sec exposures from 5 hours before the burst time to 4
hours after it. We have not found any optical emission at the
afterglow position reported by Postigo et al. (GCN 3192) during our
observation period. Coadding the ten images around the burst time
yields the 1-sigma limiting magnitude of R~11 listed below, which was
calibrated relative to USNO B1.0 catalogue.
t-t0 (sec)
start end limit mag.
-------------------------------------
-293.93 -198.93 10.9
-193.93 -98.93 10.9
-93.93 1.07 10.9
6.07 101.07 11.0
106.07 201.07 10.9
-------------------------------------
Further analysis is in progress. This message may be cited.
http://cosmic.riken.jp/grb/widget/
- GCN notice #3215
G. Kosugi, T. Yamada, H. Furusawa, Y. Matsuda,
R. Yamauchi, Y. Nakamura, N. Kawai, and A. Yoshida
report on behalf of the Subaru GRB team:
"We have observed the position of GRB 050408 afterglow reported by
de Ugarte Postigo et al. (GCN #3192) in z'-band with SuprimeCam on the
Subaru 8.2m telescope atop Mauna Kea on Apr. 09 and 10, approximately
13.3 and 37.3 hours after the burst event, respectively. The seeing
condition was around 0.6 arcsec for the both nights. We measured the
afterglow brightness to be z'(Vega) = 21.2 +/- 0.2 and 22.0 +/- 0.2,
and the temporal index to be -0.7.
Although these magnitudes are inconsistent with the magnitude of the
host galaxy candidate proposed by Lamb et al. (z = 21.39 mag; GCN #3212),
the position of the proposed host coincides with a field galaxy
(z'(AB)= 21.34 mag in our measurement) located 8 arcsec South-West to
the afterglow."
This message may be cited.
- GCN notice #3216
A. Monfardini, I. Steele, C.G. Mundell C. Guidorzi, A. Gomboc, M. Bode
(Liverpool), N. Tanvir (Hertfordshire), P. O'Brien and E. Rol
(Leicester) report:
"Since 4.3 hours after the burst, we are monitoring the field of the
GRB050408 (HETE GCN 3189) with the 2m telescopes of the ROBONET network.
We clearly detect the fading afterglow at the position suggested by
A. de Ugarte Postigo et al. (GCN3192) and then refined in subsequent
GCNs. We also detect the SDSS galaxy quoted by Lamb et al. (GCN3212) about
8arcsec from the afterglow position and conclude that this is VERY
unlikely the GRB050408 host galaxy.
This message can be cited."
- GCN notice #3217
GRB 050408: Retraction of Proposed Host Galaxy
D. Q. Lamb, D. G. York, and D. E. Reichart report:
We agree that the galaxy we proposed as the host galaxy of GRB 040508
lies ~ 8 arcsec South-West of the burst afterglow (Kosugi et al., GCN
Circular 3215; Monfardini, GCN Circular 3216) and therefore cannot be
the host galaxy of the burst.
This message may be cited.
- GCN notice #3222
O. Godet, K. L. Page, M. R. Goad, J. P. Osborne (U. Leicester), M. Capalbi,
P. Giommi (ASDC), D. Grupe, D. N. Burrows (PSU), S. Campana, G. Chincarini
(INAF-OAB), V. La Parola, T. Mineo (INAF-IASF/Palermo), S. Barthelmy, L.
Angelini, N. Gehrels (GSFC), and P. Meszaros (PSU) report on behalf of the
Swift XRT team:
The Swift XRT instrument observed GRB 050408 as a Target of Opportunity for
20 ks (exposure time) on 8/9 April 2005, beginning 40 minutes after the
HETE trigger and lasting for 60 ks of real time . Analysis of the data
shows evidence for a possible jet break at about 24 ks post-burst, with the
following parameters:
initial slope: -0.71 +0.10/-0.12
Break time : 24 +25/-12 ks
later slope -1.43 +0.72/-0.40
Both single power-law and broken power-law fits to the lightcurve are
statistically acceptable at this point. Further observations planned for
April 11 will give more information to help distinguish between the two and
determine the jet break time.
- GCN notice #3227
S. T. Holland (GSFC-USRA), M. Capalbi (ASDC), A. Morgan, S. Kobayashi,
(PSU), A. Breeveld (MSSL), P. Boyd (GSFC-UMBC), N. Gehrels (GSFC), D.
Hinshaw (GSFC-SPSYS), K. Mason (MSSL), J. Nousek (PSU), and A. Wells
(Leicester) on behalf of the Swift UVOT team report:
The Swift Ultra-Violet/Optical Telescope (UVOT) observed the field of
GRB 050408 (Sakamoto et al., GCN 3189) starting at 17:07:08 UT on 8 April
2005. There is a faint source at the location of the optical afterglow
(de Ugarte Postigo et al., GCN 3192) visible in the coadded U-band image.
This source has U = 21.30 (-0.32,+0.45) mag and the total coadded exposure
time is 2927 s. This source is at the 3-sigma detection limit of the
coadded image and is only marginally consistent with being a point source.
There is no detection in the other filters. The 3-sigma limiting
magnitudes in a 3.5 arcsecond radius circular aperture , and the coadded
exposure times, are: V = 21.3 (3866 s), B = 22.2 (2910 s), UVW1 = 17.8
(3223 s), UVM2 = 17.6 (1989 s), and UVW2 = 17.82 (3402 s). The magnitudes
reported in this Circular are based upon preliminary flight calibrations.
The first Swift/UVOT image of the field was a 100 s V-band exposure
centred 45.117 minutes after the BAT trigger. No source is detected in
this image down to a 3-sigma limiting magnitude of V = 19.9.
- GCN notice #3228
M. Bayliss, M. Nysewander, J. Haislip, J. A. Crain, A. Foster, J.
Kirschbrown, C. MacLeod, and D. Reichart report on behalf of the UNC
team of the FUN GRB Collaboration:
We have observed the position of the GRB 050408 afterglow reported by de
Ugarte Postigo et al. (GCN #3192) with three telescopes of the PROMPT
robotic array, one in each of VRcIc.
In one epoch of V-band observations, 122 x 60s exposures centered on
April 9, 02:06:44 UT (t + 9.7 hours), we have a 3 sigma detection of the
afterglow at V ~ 21.4. In a second epoch of 137 x 60s eposures centered
at 05:37:31 UT (t + 13.2 hours) we do not detect the afterglow down to a
limiting magnitude of V = 21.7 (2 sigma).
V filter calibrations were made relative to 6 Nomad stars.
PROMPT is still being built and commissioned.
- GCN notice #3232
K. Torii (Osaka U.) reports
"The error region of GRB 050408 (Sakamoto, et al. GCN 3189) was
observed by the ART 14-inch telescope. BVRcIc imaging started at 2005
April 8, 16:23:48 UT (57-s after trigger) and 60-s exposure in each
filter was repeated.
The optical afterglow (de Ugarte Postigo, et al. GCN 3192) is not
detected in our frames and the following 3-sigma upper limits are
derived relative to USNO-A2.0 (R).
MeanEpoch(UT) Magnitude Exposure
16:24:18 >16.2Rc 60s
16:28:50 >16.2Rc 60s
16:33:22 >17.0Rc 60sx5
- GCN notice #3234
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 again
the field of GRB050408 (GCN 3189) on 2005 Apr 11.21 UT.
We still do not detect a radio source coincident with the
X-ray or optical afterglow positions (GCNs 3191 and 3192).
Coaddition with our previous observation (GCN 3210) yields a
flux of 74 +- 29 uJy at the optical position."
- GCN notice #3246
M. Nysewander, D. Reichart, D. Lamb, and D. York report:
Using ugriz magnitudes from the SDSS DR3 and the transformation
equations of Smith (2002; AJ, 123, 2121), we have calculated the
UBVRcIc magnitudes of 50 sources in the field of GRB 050408:
http://www.physics.unc.edu/~mnysewan/grb050408_fc.txt
Systematic errors are typically 0.02 mag in the gri bands and 0.05
mag in the u and z bands. Statistical errors begin to dominate in u
and z at roughly 21 mag and in gri at roughly 21.5-22 mag. All of
these sources have been classified as stars by the SDSS frames
pipeline; however, some of the fainter sources may be galaxies,
regardless of this.
Users can find the statistical and systematic error on the magnitude of
any SDSS object in the field at
http://cas.sdss.org/astro/en/tools/explore/obj.asp?ra=180.571087&dec=10.850506
by clicking on the "Field" button under "PhotoObj" in the column at the
far left, and make their own decision about whether an object is a
galaxy or a star at
http://cas.sdss.org/astro/en/tools/chart/navi.asp?ra=180.571087&dec=10.850506
- GCN notice #3254
M. Capalbi (ASDC), P. Romano (INAF-OAB), V. Mangano (INAF-IASF/Palermo), O.
Godet (U. Leicester), L. Angelini (GSFC) and D. N. Burrows (PSU) report on
behalf of the
Swift XRT team:
On 10 April 2004 we reported detection of a possible jet break in Swift XRT
data on GRB 050408, with additional observations scheduled to verify the
break in the light curve (Godet et al. 2005, GCN 3222). We now have
analyzed new data extending to about 300,000 s after the burst, and can
state that the reported possible jet break is not confirmed by the later
observations. No jet break is seen in the XRT data up to 300,000 s after
the burst.
Additional observations are planned over the next several days to continue
to search for a jet break in this afterglow.
- GCN notice #3258
P.A.Milne, G.G.Williams (Steward Obs), H.-S.Park (LLNL),
on behalf of the Super-LOTIS GRB team report:
We have observed the field of GRB 050408 over two nights
with the 1.5m Kuiper telescope on Mt. Bigelow, AZ., USA.
We have performed BVRI broad-band imaging and have detected
a source at a position consistent with that reported by
A. de Ugarte Postigo et al. (GCN 3193).
UT Mag Exp(sec)
9.16 R=21.888 +/- 0.150 11x120
9.18 I=21.305 +/- 0.203 9x120
9.20 V=22.069 +/- 0.171 11x120
9.26 R=21.963 +/- 0.129 8x300
9.29 I=20.691 +/- 0.132 8x300
9.32 V=22.618 +/- 0.191 7x300
9.35 B=22.369 +/- 0.166 6x300
10.26 I=22.288 +/- 0.390 4x300
10.29 V=23.480 +/- 0.612 4x300
The field was calibrated from Landolt fields observed during
the first night. Two field stars were compared against the
field calibration compiled by Nysewander et al. (GCN 3246).
We were brighter in all cases, by 0.20/0.02/0.16/0.14 magnitudes
for B/V/R/I respectively.
Further observations are planned to obtain images suitable for
use in image subtraction.
- GCN notice #3261
B. Kahharov, M. Ibrahimov, D. Sharapov (MAO), A.Pozanenko (IKI),
V.Rumyantsev (CrAO), G.Beskin (SAO) report:
We observed the afterglow (Ugarte et al., GCN 3192) of the HETE GRB050408
(Sakamoto et al., GCN 3189) with 1.5m telescope of the Maidanak
Astronomical Observatory (MAO), Uzbekistan under modarate weather conditions
(seeing ~1.8 arcsec) on April 9 between 19:29:30 - 20:09:00 (UT). The
optical source is clearly visible in the position of OT (Ugarte et al., GCN
3192; Huang et al., GCN 3196). A preliminary R-photometry against of
USNO-B1.0 Catalog is the following:
Mean time Exposure Mag.
(UT) (s)
Apr. 9.828 7x300 22.55 +/- 0.35
This message can be cited.
- GCN notice #3262
I. Bikmaev, N. Sakhibullin (KSU/AST), Z. Aslan, I. Khamitov (TUG),
U. Kiziloglu (METU), A. Alpar (SabUni), R. Burenin, M. Pavlinsky,
R. Sunyaev (IKI), report:
We have observed OT of GRB 050408 (A. de Ugarte Postigo et al., GCN
3192) with Rc-filter and ANDOR CCD at the Russian-Turkish 1.5-m telescope
(RTT150, Bakyrlytepe, Turkey). We have made a set of 30 exposures with
5 min duration each during UT 18:30 - 20:10 , April 13. The weather was
clear with average seeing of 1.8 arcsec.
We have marginaly detected the OT at the limit of co-added frame with
Rc = 23.7 +/-0.2 mag.
We have re-reduced our previous observations (Aslan et al, GCN 3198)
by using Landolt standard stars.
RTT150 photometry of OT is given below:
t-t0 (hours) Rc err exposure
midtime (sec)
3.72 21.01 0.07 900 (30*30s)
4.37 21.10 0.05 1080 (18*60s)
4.89 21.25 0.05 960 (16*60s)
5.39 21.27 0.05 960 (16*60s)
5.79 21.44 0.06 960 (16*60s)
6.55 21.37 0.06 720 (12*60s)
6.85 21.50 0.06 720 (12*60s)
8.24 21.64 0.07 1200 (20*60s)
8.75 21.60 0.07 1200 (20*60s)
123.78 23.7 0.2 9000 (30*300s)
The power law decay index between 3.7h and 8.7h calculated on the
basis of the RTT150 data in Rc-band is -0.68+/-0.06 and the newly
obtained value of Rc = 23.7 shows that the lightcurve is still fit by a
single power law of -0.7 (GCN 3215, GCN 3222, GCN 3254).
RTT150 optical light curve of OT GRB050408 is shown at
http://www.tug.tubitak.gov.tr/~irekk/grb/grb050408/lc.jpg
This message may be cited.
- GCN notice #3454
A. Henden (AAVSO/USNO) reports on behalf of the USNO GRB Team:
We have acquired BVRcIc all-sky photometry for 11x11arcmin
fields centered on the coordinates of recent GRB localizations
with the USNOFS 1.0-m telescope on one photometric night
but with bright moonlight. Stars brighter than V=12.0
are saturated and should be used with care. We have placed
the photometric data on our anonymous ftp site:
ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb050319.dat
ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb050401.dat
ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb050408.dat
ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb050416.dat
ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb050502a.dat
ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb050509b.dat
The astrometry in these files is based on linear plate solutions
with respect to UCAC2. The external errors are less than 100mas.
The estimated external photometric error is about 0.03mag.
Since these bursts had identified optical afterglows, we expect
to improve the photometric calibration on subsequent nights.
As always, you should check the dates on the .dat file prior to
final publication to get the latest photometry. There is
a README file on the ftp directory to give you information
about the procedures used to calibrate these fields.
- GCN notice #3508
S. Covino (OAB), M. Capalbi, M. Perri (ASDC), V. Mangano (INAF-IASF/Palermo),
and D. N. Burrows (PSU) report on behalf of the Swift XRT team:
We have analyzed the Swift XRT data from 12 observations of GRB 050408
(Sakamoto et al., GCN 3189) performed over a period of 38 days.
The [0.3-10] keV light curve shows a break at (1.2 =B1 0.5 )E5 seconds after
the trigger. We interpret this as a jet break, implying a jet opening angle
of 8.2 degrees, given an isotropic-equivalent gamma-ray
energy of 1.3E52 erg (Berger et al., GCN 3201).
- GCN notice #3561
GRB 050408: ARC 3.5-meter NIR Observations
J. Flasher (Colorado), F. Hearty (Colorado), G. Stringfellow (Colorado),=20
J. Walawender (Colorado), D. Q. Lamb (Chicago), T. Lisker (Washington),=20
V. Debattista (Washington), J. Dembicky (APO), J. Barentine (APO),=20
R. McMillan (APO), B. Ketzeback (APO), and D. G. York (Chicago) report=20
on behalf of the ARC GRB team of the FUN GRB collaboration:
We observed the afterglow (Wells et al., GCN Circular No. 3191; Postigo
et al., GCN Circular No. 3192) of GRB 050408, a burst localized by
HETE-2 (Sakamoto et al., GCN Circular No. 3189), on the night of April
8th, using NIC-FPS on the ARC 3.5-meter telescope at Apache Point
Observatory. The observation began at 04.47 UT (12.29 hours after the
burst) and ended at 07.06 UT (14.68 hours after the burst). The
observation consisted of a series of 120-, 120-, 20-, and 20-second
exposures in Z, J, H, and Ks, respectively. We have constructed
stacked images of the GRB field, corresponding to 20-minute exposures=20
in each filter. We detect the afterglow in all four filters, and=20
measure Z =3D 21.8 =B1 0.12, calibrated relative to the SDSS stars in the=
=20
field.
NIC-FPS is currently in its commissioning phase.
This message may be cited.
- astro-ph/0512081 from 4 Dec 2005
Foley: GRB 050408: An Atypical Gamma-Ray Burst as a Probe of an Atypical
The bright GRB 050408 was localized by HETE-II near local midnight, enabling
an impressive ground-based followup effort as well as space-based followup from
Swift. The Swift data from the X-Ray Telescope (XRT) and our own optical
photometry and spectrum of the afterglow provide the cornerstone for our
analysis. Under the traditional assumption that the visible waveband was above
the peak synchrotron frequency and below the cooling frequency, the optical
photometry from 0.03 to 5.03 days show an afterglow decay corresponding to an
electron energy index of p_lc = 2.05 +/- 0.04, without a jet break as suggested
by others. A break is seen in the X-ray data at early times (at ~12600 sec
after the GRB). The spectral slope of the optical spectrum is consistent with
p_lc assuming a host-galaxy extinction of A_V = 1.18 mag. The optical-NIR
broadband spectrum is also consistent with p = 2.05, but prefers A_V = 0.57
mag. The X-ray afterglow shows a break at 1.26 x 10^4 sec, which may be the
result of a refreshed shock. This burst stands out in that the optical and
X-ray data suggest a large H I column density of N_HI ~ 10^22 cm^-2; it is very
likely a damped Lyman alpha system and so the faintness of the host galaxy (M_V
> -18 mag) is noteworthy. Moreover, we detect extraordinarily strong Ti II
absorption lines with a column density through the GRB host that exceeds the
largest values observed for the Milky Way by an order of magnitude.
Furthermore, the Ti II equivalent width is in the top 1% of Mg II
absorption-selected QSOs. This suggests that the large-scale environment of GRB
050408 has significantly lower Ti depletion than the Milky Way and a large
velocity width (delta v > 200 km/s).
- astro-ph/0610845 from 27 Oct 2006
Capalbi: Long-term monitoring of the X-ray afterglow of GRB 050408 with Swift/XRT
We present observations of the X-ray afterglow of GRB 050408, a gamma-ray
burst discovered by HETE-II. Swift began observing the field 42 min after the
burst, performing follow-up over a period of 38 d (thus spanning three decades
in time).The X-ray light curve showed a steepening with time, similar to many
other afterglows. However, the steepening was unusually smooth, over the
duration of the XRT observation, with no clear break time. The early decay was
too flat to be described in terms of standard models. We therefore explore
alternative explanations, such as the presence of a structured afterglow or of
long-lasting energy injection into the fireball from the central GRB engine.
The lack of a sharp break puts constraints on these two models. In the former
case, it may indicate that the angular energy profile of the jet was not a
simple power law, while in the second model it implies that injection did not
stop abruptly. The late decay may be due either to a standard afterglow (that
is, with no energy injection), or to a jetted outflow still being refreshed. A
significant amount of absorption was present in the X-ray spectrum,
corresponding to a rest-frame Hydrogen column density NH = 1.2
(-0.3,+0.4)*10^22 cm^-2, indicative of a dense environment.
- astro-ph/0612545 from 19 Dec 2006
Postigo: Extensive multiband study of the X-ray rich GRB 050408. A likely off-axis event with an intense energy injection
Aims. Understand the shape and implications of the multiband light curve of
GRB 050408, an X-ray rich (XRR) burst. Methods. We present a multiband optical
light curve, covering the time from the onset of the gamma-ray event to several
months after, when we only detect the host galaxy. Together with X-ray,
millimetre and radio observations we compile what, to our knowledge, is the
most complete multiband coverage of an XRR burst afterglow to date. Results.
The optical and X-ray light curve is characterised by an early flattening and
an intense bump peaking around 6 days after the burst onset. We explain the
former by an off-axis viewed jet, in agreement with the predictions made for
XRR by some models, and the latter with an energy injection equivalent in
intensity to the initial shock. The analysis of the spectral flux distribution
reveals an extinction compatible with a low chemical enrichment surrounding the
burst. Together with the detection of an underlying starburst host galaxy we
can strengthen the link between XRR and classical long-duration bursts.
- 1002.3849 from 23 Feb 10
M. Arimoto et al.: Spectral Lag Relations in GRB Pulses Detected with HETE-2
T. Tamagawa, Y. Shirasaki, S. Sugita, I. Takahashi, J.-L. Atteia, A. Pelangeon, R. Vanderspek, C. Graziani, G. Prigozhin, J. Villasenor, J. G.
Jernigan, G. B. Crew, T. Sakamoto, G. R. Ricker, S. E. Woosley, N. Butler, A. Levine, J. P. Doty, T. Q. Donaghy, D. Q. Lamb, E. Fenimore, M.
Galassi, M. Boer, J.-P. Dezalay, J.-F. Olive, J. Braga, R. Manchanda, G. Pizzichini
Using a pulse-fit method, we investigate the spectral lags between the traditional gamma-ray band (50-400 keV) and the X-ray band (6-25 keV)
for 8 GRBs with known redshifts (GRB 010921, GRB 020124, GRB 020127, GRB 021211, GRB 030528, GRB 040924, GRB 041006, GRB 050408) detected with
the WXM and FREGATE instruments aboard the HETE-2 satellite. We find several relations for the individual GRB pulses between the spectral lag
and other observables, such as the luminosity, pulse duration, and peak energy (Epeak). The obtained results are consistent with those for
BATSE, indicating that the BATSE correlations are still valid at lower energies (6-25 keV). Furthermore, we find that the photon energy
dependence for the spectral lags can reconcile the simple curvature effect model. We discuss the implication of these results from various
points of view.
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