- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Sat 24 Jul 10 00:42:22 UT
NOTICE_TYPE: Fermi-GBM Flight Position
RECORD_NUM: 47
TRIGGER_NUM: 301624927
GRB_RA: 154.400d {+10h 17m 36s} (J2000),
154.796d {+10h 19m 11s} (current),
152.437d {+10h 09m 45s} (1950)
GRB_DEC: +84.500d {+84d 30' 00"} (J2000),
+84.447d {+84d 26' 49"} (current),
+84.749d {+84d 44' 57"} (1950)
GRB_ERROR: 16.22 [deg radius, statistical plus systematic]
GRB_INTEN: 83 [cnts/sec]
DATA_SIGNIF: 8.40 [sigma]
INTEG_TIME: 4.096 [sec]
GRB_DATE: 15401 TJD; 205 DOY; 10/07/24
GRB_TIME: 2525.98 SOD {00:42:05.98} UT
GRB_PHI: 43.00 [deg]
GRB_THETA: 45.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO: 0.87
LOC_ALGORITHM: 3 (version number of)
MOST_LIKELY: 96% GRB
2nd_MOST_LIKELY: 1% Generic Transient
DETECTORS: 0,1,0, 1,0,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN: 123.26d {+08h 13m 03s} +19.92d {+19d 55' 30"}
SUN_DIST: 65.37 [deg] Sun_angle= -2.1 [hr] (East of Sun)
MOON_POSTN: 278.93d {+18h 35m 44s} -23.49d {-23d 29' 25"}
MOON_DIST: 116.52 [deg]
MOON_ILLUM: 96 [%]
GAL_COORDS: 126.94, 31.38 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 101.27, 63.74 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Flight-calculated Coordinates.
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Sat 24 Jul 10 00:42:31 UT
NOTICE_TYPE: Fermi-GBM Flight Position
RECORD_NUM: 57
TRIGGER_NUM: 301624927
GRB_RA: 119.667d {+07h 58m 40s} (J2000),
119.933d {+07h 59m 44s} (current),
118.399d {+07h 53m 36s} (1950)
GRB_DEC: +68.717d {+68d 42' 60"} (J2000),
+68.687d {+68d 41' 15"} (current),
+68.852d {+68d 51' 06"} (1950)
GRB_ERROR: 6.88 [deg radius, statistical plus systematic]
GRB_INTEN: 261 [cnts/sec]
DATA_SIGNIF: 25.40 [sigma]
INTEG_TIME: 4.096 [sec]
GRB_DATE: 15401 TJD; 205 DOY; 10/07/24
GRB_TIME: 2525.98 SOD {00:42:05.98} UT
GRB_PHI: 25.00 [deg]
GRB_THETA: 55.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO: 0.56
LOC_ALGORITHM: 3 (version number of)
MOST_LIKELY: 95% GRB
2nd_MOST_LIKELY: 4% Generic Transient
DETECTORS: 0,1,0, 1,0,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN: 123.26d {+08h 13m 03s} +19.92d {+19d 55' 29"}
SUN_DIST: 48.81 [deg] Sun_angle= 0.2 [hr] (West of Sun)
MOON_POSTN: 278.93d {+18h 35m 44s} -23.49d {-23d 29' 24"}
MOON_DIST: 133.04 [deg]
MOON_ILLUM: 96 [%]
GAL_COORDS: 146.91, 31.22 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 105.23, 46.84 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Flight-calculated Coordinates.
COMMENTS: This trigger occurred at longitude,latitude = 9.40,7.15 [deg].
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Sat 24 Jul 10 00:42:52 UT
NOTICE_TYPE: Fermi-GBM Ground Position
RECORD_NUM: 71
TRIGGER_NUM: 301624927
GRB_RA: 130.070d {+08h 40m 17s} (J2000),
130.330d {+08h 41m 19s} (current),
128.827d {+08h 35m 19s} (1950)
GRB_DEC: +70.260d {+70d 15' 36"} (J2000),
+70.222d {+70d 13' 19"} (current),
+70.437d {+70d 26' 13"} (1950)
GRB_ERROR: 1.30 [deg radius, statistical only]
DATA_SIGNIF: 79.70 [sigma]
DATA_INTERVAL: 4.096 [sec]
GRB_DATE: 15401 TJD; 205 DOY; 10/07/24
GRB_TIME: 2525.98 SOD {00:42:05.98} UT
GRB_PHI: 30.00 [deg]
GRB_THETA: 56.00 [deg]
E_RANGE: 44.032 - 279.965 [keV]
LOC_ALGORITHM: 413 (Gnd S/W Version number)
SUN_POSTN: 123.26d {+08h 13m 03s} +19.92d {+19d 55' 29"}
SUN_DIST: 50.48 [deg] Sun_angle= -0.5 [hr] (East of Sun)
MOON_POSTN: 278.94d {+18h 35m 45s} -23.49d {-23d 29' 22"}
MOON_DIST: 129.79 [deg]
MOON_ILLUM: 96 [%]
GAL_COORDS: 144.31, 34.52 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 109.57, 49.53 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Ground-calculated Coordinates.
COMMENTS: This Notice was ground-generated -- not flight-generated.
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Sat 24 Jul 10 00:43:00 UT
NOTICE_TYPE: Fermi-GBM Ground Position
RECORD_NUM: 72
TRIGGER_NUM: 301624927
GRB_RA: 126.190d {+08h 24m 46s} (J2000),
126.460d {+08h 25m 50s} (current),
124.902d {+08h 19m 36s} (1950)
GRB_DEC: +70.640d {+70d 38' 24"} (J2000),
+70.605d {+70d 36' 19"} (current),
+70.802d {+70d 48' 07"} (1950)
GRB_ERROR: 2.05 [deg radius, statistical only]
DATA_SIGNIF: 81.50 [sigma]
DATA_INTERVAL: 4.096 [sec]
GRB_DATE: 15401 TJD; 205 DOY; 10/07/24
GRB_TIME: 2525.98 SOD {00:42:05.98} UT
GRB_PHI: 29.00 [deg]
GRB_THETA: 55.00 [deg]
E_RANGE: 44.032 - 279.965 [keV]
LOC_ALGORITHM: 413 (Gnd S/W Version number)
SUN_POSTN: 123.26d {+08h 13m 03s} +19.92d {+19d 55' 29"}
SUN_DIST: 50.72 [deg] Sun_angle= -0.2 [hr] (East of Sun)
MOON_POSTN: 278.94d {+18h 35m 45s} -23.49d {-23d 29' 22"}
MOON_DIST: 130.25 [deg]
MOON_ILLUM: 96 [%]
GAL_COORDS: 144.26, 33.16 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 107.50, 49.39 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Ground-calculated Coordinates.
COMMENTS: This Notice was ground-generated -- not flight-generated.
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Sat 24 Jul 10 00:42:40 UT
NOTICE_TYPE: Fermi-GBM Flight Position
RECORD_NUM: 69
TRIGGER_NUM: 301624927
GRB_RA: 115.900d {+07h 43m 36s} (J2000),
116.397d {+07h 45m 35s} (current),
113.510d {+07h 34m 02s} (1950)
GRB_DEC: +81.717d {+81d 42' 60"} (J2000),
+81.691d {+81d 41' 26"} (current),
+81.833d {+81d 49' 59"} (1950)
GRB_ERROR: 5.60 [deg radius, statistical plus systematic]
GRB_INTEN: 543 [cnts/sec]
DATA_SIGNIF: 56.80 [sigma]
INTEG_TIME: 4.096 [sec]
GRB_DATE: 15401 TJD; 205 DOY; 10/07/24
GRB_TIME: 2525.98 SOD {00:42:05.98} UT
GRB_PHI: 36.00 [deg]
GRB_THETA: 45.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO: 0.52
LOC_ALGORITHM: 3 (version number of)
MOST_LIKELY: 95% GRB
2nd_MOST_LIKELY: 4% Generic Transient
DETECTORS: 0,1,0, 1,0,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN: 123.26d {+08h 13m 03s} +19.92d {+19d 55' 29"}
SUN_DIST: 61.83 [deg] Sun_angle= 0.5 [hr] (West of Sun)
MOON_POSTN: 278.94d {+18h 35m 45s} -23.49d {-23d 29' 23"}
MOON_DIST: 121.39 [deg]
MOON_ILLUM: 96 [%]
GAL_COORDS: 132.14, 28.70 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 97.00, 58.91 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Flight-calculated Coordinates.
COMMENTS: This trigger occurred at longitude,latitude = 9.40,7.15 [deg].
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Sat 24 Jul 10 00:43:27 UT
NOTICE_TYPE: Fermi-GBM Flight Position
RECORD_NUM: 90
TRIGGER_NUM: 301624927
GRB_RA: 131.567d {+08h 46m 16s} (J2000),
132.203d {+08h 48m 49s} (current),
128.428d {+08h 33m 43s} (1950)
GRB_DEC: +85.033d {+85d 01' 60"} (J2000),
+84.994d {+84d 59' 39"} (current),
+85.212d {+85d 12' 45"} (1950)
GRB_ERROR: 4.37 [deg radius, statistical plus systematic]
GRB_INTEN: 914 [cnts/sec]
DATA_SIGNIF: 94.30 [sigma]
INTEG_TIME: 4.096 [sec]
GRB_DATE: 15401 TJD; 205 DOY; 10/07/24
GRB_TIME: 2525.98 SOD {00:42:05.98} UT
GRB_PHI: 43.00 [deg]
GRB_THETA: 45.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO: 0.62
LOC_ALGORITHM: 3 (version number of)
MOST_LIKELY: 96% GRB
2nd_MOST_LIKELY: 3% Generic Transient
DETECTORS: 0,1,0, 1,0,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN: 123.26d {+08h 13m 03s} +19.92d {+19d 55' 29"}
SUN_DIST: 65.13 [deg] Sun_angle= -0.6 [hr] (East of Sun)
MOON_POSTN: 278.94d {+18h 35m 46s} -23.49d {-23d 29' 20"}
MOON_DIST: 117.64 [deg]
MOON_ILLUM: 96 [%]
GAL_COORDS: 127.93, 29.43 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 97.18, 62.66 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Flight-calculated Coordinates.
COMMENTS: This trigger occurred at longitude,latitude = 9.40,7.15 [deg].
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Sat 24 Jul 10 00:42:43 UT
NOTICE_TYPE: Fermi-GBM Ground Position
RECORD_NUM: 56
TRIGGER_NUM: 301624927
GRB_RA: 116.420d {+07h 45m 41s} (J2000),
116.683d {+07h 46m 44s} (current),
115.166d {+07h 40m 40s} (1950)
GRB_DEC: +67.700d {+67d 42' 00"} (J2000),
+67.674d {+67d 40' 25"} (current),
+67.821d {+67d 49' 16"} (1950)
GRB_ERROR: 4.89 [deg radius, statistical only]
DATA_SIGNIF: 20.50 [sigma]
DATA_INTERVAL: 4.096 [sec]
GRB_DATE: 15401 TJD; 205 DOY; 10/07/24
GRB_TIME: 2525.98 SOD {00:42:05.98} UT
GRB_PHI: 23.00 [deg]
GRB_THETA: 55.00 [deg]
E_RANGE: 44.032 - 279.965 [keV]
LOC_ALGORITHM: 413 (Gnd S/W Version number)
SUN_POSTN: 123.26d {+08h 13m 03s} +19.92d {+19d 55' 29"}
SUN_DIST: 47.93 [deg] Sun_angle= 0.4 [hr] (West of Sun)
MOON_POSTN: 278.94d {+18h 35m 45s} -23.49d {-23d 29' 23"}
MOON_DIST: 134.47 [deg]
MOON_ILLUM: 96 [%]
GAL_COORDS: 148.16, 30.07 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 103.95, 45.54 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Ground-calculated Coordinates.
COMMENTS: This Notice was ground-generated -- not flight-generated.
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Sat 24 Jul 10 00:43:47 UT
NOTICE_TYPE: Fermi-GBM Ground Position
RECORD_NUM: 128
TRIGGER_NUM: 301624927
GRB_RA: 125.950d {+08h 23m 48s} (J2000),
126.217d {+08h 24m 52s} (current),
124.676d {+08h 18m 42s} (1950)
GRB_DEC: +70.200d {+70d 12' 00"} (J2000),
+70.165d {+70d 09' 55"} (current),
+70.361d {+70d 21' 39"} (1950)
GRB_ERROR: 1.00 [deg radius, statistical only]
DATA_SIGNIF: 132.00 [sigma]
DATA_INTERVAL: 4.096 [sec]
GRB_DATE: 15401 TJD; 205 DOY; 10/07/24
GRB_TIME: 2525.98 SOD {00:42:05.98} UT
GRB_PHI: 30.00 [deg]
GRB_THETA: 56.00 [deg]
E_RANGE: 44.032 - 279.965 [keV]
LOC_ALGORITHM: 413 (Gnd S/W Version number)
SUN_POSTN: 123.26d {+08h 13m 04s} +19.92d {+19d 55' 29"}
SUN_DIST: 50.27 [deg] Sun_angle= -0.2 [hr] (East of Sun)
MOON_POSTN: 278.95d {+18h 35m 47s} -23.49d {-23d 29' 18"}
MOON_DIST: 130.66 [deg]
MOON_ILLUM: 96 [%]
GAL_COORDS: 144.79, 33.18 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 107.63, 48.95 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Ground-calculated Coordinates.
COMMENTS: This Notice was ground-generated -- not flight-generated.
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Sat 24 Jul 10 00:43:42 UT
NOTICE_TYPE: Fermi-GBM Ground Position
RECORD_NUM: 92
TRIGGER_NUM: 301624927
GRB_RA: 126.290d {+08h 25m 10s} (J2000),
126.557d {+08h 26m 14s} (current),
125.018d {+08h 20m 04s} (1950)
GRB_DEC: +70.210d {+70d 12' 36"} (J2000),
+70.175d {+70d 10' 30"} (current),
+70.372d {+70d 22' 20"} (1950)
GRB_ERROR: 1.06 [deg radius, statistical only]
DATA_SIGNIF: 101.00 [sigma]
DATA_INTERVAL: 4.096 [sec]
GRB_DATE: 15401 TJD; 205 DOY; 10/07/24
GRB_TIME: 2525.98 SOD {00:42:05.98} UT
GRB_PHI: 30.00 [deg]
GRB_THETA: 56.00 [deg]
E_RANGE: 44.032 - 279.965 [keV]
LOC_ALGORITHM: 413 (Gnd S/W Version number)
SUN_POSTN: 123.26d {+08h 13m 04s} +19.92d {+19d 55' 29"}
SUN_DIST: 50.29 [deg] Sun_angle= -0.2 [hr] (East of Sun)
MOON_POSTN: 278.95d {+18h 35m 47s} -23.49d {-23d 29' 18"}
MOON_DIST: 130.58 [deg]
MOON_ILLUM: 96 [%]
GAL_COORDS: 144.75, 33.29 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 107.79, 49.00 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Ground-calculated Coordinates.
COMMENTS: This Notice was ground-generated -- not flight-generated.
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Sat 24 Jul 10 00:42:48 UT
NOTICE_TYPE: Fermi-GBM Ground Position
RECORD_NUM: 68
TRIGGER_NUM: 301624927
GRB_RA: 110.680d {+07h 22m 43s} (J2000),
110.994d {+07h 23m 58s} (current),
109.187d {+07h 16m 45s} (1950)
GRB_DEC: +72.890d {+72d 53' 24"} (J2000),
+72.869d {+72d 52' 09"} (current),
+72.985d {+72d 59' 06"} (1950)
GRB_ERROR: 2.25 [deg radius, statistical only]
DATA_SIGNIF: 58.60 [sigma]
DATA_INTERVAL: 4.096 [sec]
GRB_DATE: 15401 TJD; 205 DOY; 10/07/24
GRB_TIME: 2525.98 SOD {00:42:05.98} UT
GRB_PHI: 26.00 [deg]
GRB_THETA: 50.00 [deg]
E_RANGE: 44.032 - 279.965 [keV]
LOC_ALGORITHM: 413 (Gnd S/W Version number)
SUN_POSTN: 123.26d {+08h 13m 03s} +19.92d {+19d 55' 29"}
SUN_DIST: 53.40 [deg] Sun_angle= 0.8 [hr] (West of Sun)
MOON_POSTN: 278.94d {+18h 35m 45s} -23.49d {-23d 29' 23"}
MOON_DIST: 130.17 [deg]
MOON_ILLUM: 96 [%]
GAL_COORDS: 142.23, 28.13 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 99.33, 50.12 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Ground-calculated Coordinates.
COMMENTS: This Notice was ground-generated -- not flight-generated.
- GCN NOTICE
TITLE: GCN/INTEGRAL NOTICE
NOTICE_DATE: Sat 24 Jul 10 00:43:19 UT
NOTICE_TYPE: INTEGRAL SPI ACS Trigger
TRIGGER_NUM: 6050, Sub_Num: 0
GRB_INTEN: 9.17 [sigma]
GRB_TIME: 2521.99 SOD {00:42:01.99} UT
GRB_DATE: 15401 TJD; 205 DOY; 10/07/24
COMMENTS: INTEGRAL SPI_ACS GRB Trigger.
COMMENTS:
COMMENTS: NOTE: This SPIACS event is temporally(18.0<100sec)
coincident with the SWIFT_BAT event (trignum=429868).
COMMENTS:
COMMENTS: The SPIACS lightcurve can be found at:
COMMENTS: ftp://isdcarc.unige.ch/arc/FTP/ibas/spiacs/2010-07/2010-07-24T00-42-01.8250-132+88-00007-0.lc
- GCN Circular #10977
P. N. Bhat (UAH)
reports on behalf of the Fermi GBM Team:
"At 00:42:05.98 UT on 24 July 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100724B (trigger 301624927 / 100724029).
The on-ground calculated location, using the GBM trigger
data, is RA = 124.16, DEC = 74.42 (J2000 degrees,
equivalent to 08 h 16.6 m, 74 d 25.2 '), with an uncertainty
of 1.0 degree (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 52 degrees.
GBM triggered an automatic repoint request to the Fermi
Observatory to execute a maneuver following this trigger
and track the burst location for the next 5 hours.
However due to spacecraft constraints, the slew did not
commence until 2733 s after the trigger.
This burst was also independently detected by INTEGRAL SPI-ACS.
The GBM light curve consists of several pulses
with a duration (T90) of about 111.6 s (50-300 keV).
The time-averaged spectrum from T0-5.12 s to T0+140.29 s is
best fit by a Band function with Epeak = 467.8 +15.3/-13.1 keV,
alpha = 0.84 +/- 0.01, and beta = -1.84 +/- 0.01
(Cstat 18069 for 736 d.o.f.).
The event fluence (8-1000 keV) in this time interval is
(2.44 +/- 0.006)E-04 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+52 s in the 8-1000 keV band
is 7.06 +/- 0.01 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
- GCN Circular #10978
Yasuyuki Tanaka, Masanori Ohno (ISAS/JAXA), Hiromitsu Takahashi,
Takeshi Uehara (Hiroshima University), Nicola Omodei (Stanford Univ.),
James Chiang (SLAC) and Sylvain Guiriec (UAH) report on behalf of the
Fermi LAT and GBM teams:
At 00:42:06 UT on 25 July 2010, the Fermi Large Area Telescope (LAT)
detected gamma-rays from the long GRB 100724B. This burst was detected
and localized by the Fermi Gamma-Ray Burst Monitor (GBM) (trigger
301624927 / 100724029, GCN 10977).
The best LAT on-ground localization for this burst is RA, Dec =
120.04, 76.74 (08h 00m 09.6s, 76d 44' 24", J2000) with a 90%
containment radius of 1.1 degrees (statistical; 68% containment radius
0.6 degrees). At the GBM trigger time, this location was at angle of
49 degrees from the LAT boresight and approximately 18 degrees from
the Earth's limb. The GBM trigger caused an Autonomous Repoint
Request. However, owing to the proximity of the burst location to the
Earth horizon and constraints on the spacecraft pointing, the angle of
the source with respect to the boresight remained greater than 40
degrees for the first 2700 seconds after trigger.
Using a non-standard data selection designed to maximize the low
energy acceptance, the LAT light curve shows two distinct peaks at ~20
and ~64 s after the GBM trigger and a smaller sub-peak at ~77 s
post-trigger. A joint spectral fit with the GBM data yields a photon
index in the LAT band (> 20 MeV) of -2.48 +/- 0.01 (stat). This is
consistent with an extrapolation of the high energy part of the
spectrum in the GBM band. This result differs somewhat from the fit
reported in GCN 10977. In order to account for a spectral feature
below 100 keV, we have included a low energy spectral component in
addition to the usual Band function model; this accounts for the
difference found in the high energy photon index.
Further analysis is ongoing.
The Fermi LAT point of contact for this burst is Yasuyuki Tanaka
(tanaka@astro.isas.jaxa.jp).
The Fermi LAT is a pair conversion telescope designed to cover the
energy band from 20 MeV to greater than 300 GeV. It is the product of
an international collaboration between NASA and DOE in the U.S. and
many scientific institutions across France, Italy, Japan and Sweden.
- GCN Circular #10981
S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin,
P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf
of the Konus-Wind team, report:
The bright long hard GRB 100724B
(Fermi/GBM trigger 301624927: Bhat, GCN 10977;
localized by Fermi/LAT: Tanaka et al., GCN 10978)
triggered Konus-Wind at T0=2526.266s UT (00:42:06.266)
The burst light curve shows a complex structure with
a total duration of ~240 s. It consists of an initial harder part,
~90 s in duration, followed by a softer one, lasting to T0 + 230 s.
The emission is seen up to 10 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB100724_T02526/
As observed by Konus-Wind the burst
had a fluence of 4.1(+/-0.3)x10-4 erg/cm2,
and a 256-ms peak flux, measured from T0+59.648s,
of 1.0(+/- 0.1)x10-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum of the burst
(from T0 to T0+228.608 s) is best fit
in the 20 keV - 10 MeV range by the GRB (Band)
model, for which:
the low-energy photon index alpha = -0.87 (-0.06, +0.06),
the high energy photon index beta = -2.0 (-0.09, +0.07),
the peak energy Ep = 369(-37, +42)keV (chi2 = 86/87 dof).
The spectrum at the maximum count rate
(measured from T0+57.856 to T0+61.952 s) is best fit
in the 20 keV - 10 MeV range by the GRB (Band)
model, for which:
the low-energy photon index alpha = -0.8 (+/-0.1),
the high energy photon index beta = -2.1 (+/-0.15),
the peak energy Ep = 418(-58, +66)keV (chi2 = 84/87 dof).
All the quoted results are preliminary.
All the quoted errors are at the 90% confidence level.
- GCN Circular #10994
M. Marisaldi, F. Fuschino, C. Labanti, M. Galli, A. Bulgarelli, F.=20
Gianotti, M. Trifoglio, G. Di Cocco (INAF/IASF Bologna), E. Del Monte,=20
I. Donnarumma, Y. Evangelista, M. Feroci, F. Lazzarotto, L. Pacciani, P.=20
Soffitta, E. Costa, I. Lapshov, M. Rapisarda (INAF/IASF Rome), G.=20
Barbiellini, F. Longo, E. Moretti (INFN Trieste), A. Giuliani, A. Chen,=20
S. Mereghetti, F. Perotti, P. Caraveo (INAF/IASF Milan), M. Tavani, G.=20
Pucella, V. Vittorini, A. Argan, A. Trois, G. Piano, S. Sabatini=20
(INAF/IASF Rome), A. Pellizzoni, M. Pilia (INAF/OA Cagliari), S.=20
Vercellone, F. D'Ammando (INAF/IASF Palermo), P. W. Cattaneo, A.=20
Rappoldi (INFN Pavia), P. Picozza, A. Morselli, E. Striani, (INFN=20
Roma-2), M. Prest, E. Vallazza (Universita` dell'Insubria), P. Lipari,=20
D. Zanello (INFN Roma-1), P. Giommi, C. Pittori, F. Lucarelli, P.=20
Santolamazza, F. Verrecchia (ASDC) and L. Salotti (ASI), on behalf of=20
the AGILE Team, report:
"The AGILE Gamma-Ray Imaging Detector (GRID) and Mini-Calorimeter (MCAL)0
detected at gamma-ray energies the long bright GRB 100724B (Bhat, GCN
10977; Tanaka et al., GCN 10978; Golenetskii et al., GCN 10981).
The GRB triggered AGILE-MCAL, sensitive in the energy range 330 keV -=20
100 MeV, on 24 July 2010 at 00:42:00 UT (T0).
As seen by MCAL the burst has a duration (T90) of ~96 s, with observable=20
emission up to ~T0+150 s. The GRB emission has significant detection in=20
MCAL up to an energy of about 80 MeV.
The time integrated spectrum in the time interval [T0, T0+150.0 s]
can be fit in the energy range 500 keV - 80 MeV with a single powerlaw
with photon index -2.09 (-0.06, +0.08) (reduced chi2 =3D 0.94 with 39=20
d.o.f.). The estimated fluence is (2.7 =B1 0.2)x10-4 erg/cm2 in the same=20
energy range. All reported errors are at the 90% confidence level.
AGILE-GRID shows a definite detection above 100 MeV. Further analysis=20
are in progress.
This message may be cited."
- GCN Circular #10995
T. Uehara, Y. Hanabata, T. Takahashi, Y. Fukazawa (Hiroshima U.),
N. Vasquez (Tokyo Tech.) K. Yamaoka (Aoyama Gakuin U.), S. Sugita (Nagoya U.),
Y. Terada, M. Tashiro, W. Iwakiri, K. Takahara, T. Yasuda (Saitama U.),
M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA),
Y. E. Nakagawa, T. Tamagawa (RIKEN), N. Ohmori, A. Daikyuji, Y. Nishioka,
M. Yamauchi (Univ. of Miyazaki), Y. Urata, H. M. Lin, P. Tsai (NCU),
K. Nakazawa, K. Makishima (Univ. of Tokyo),
S. Hong (Nihon U.), on behalf of the Suzaku WAM team, report:
The bright long GRB 100724B (Fermi/GBM trigger #301624927 ; P. N. Bhat et al., GCN 10977)
triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an
energy range of 50 keV - 5 MeV at 00:42:04.70 UT (=T0).
The observed light curve shows a multi-peaked structure starting at T0-7s, ending
at T0+143s with a duration (T90) of about 103 seconds.
The fluence in 100 - 1000 keV was 1.63(+0.03/-0.07) x 10^-4 erg/cm^2.
The 1-s peak flux measured from T0+65s was 9.3 photons/cm^2/s in the same
energy range.
Preliminary result shows that the time-averaged spectrum from
T0-4.1s to T0+141.3s is well fitted by a power-law with exponential cutoff model:
dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
alpha 1.09 (+0.18/-0.19), and
Epeak 666 (+107/-67) keV (chi^2/d.o.f. = 22.8/22).
All the quoted errors are at statistical 90% confidence level.
The light curves for this burst are available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html
The light curves with 1-sec time resolution for this burst will be appeared at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html
- GCN Circular #10996
A. Giuliani (INAF/IASF Milano), M. Tavani (INAF/IASF Roma), F. Longo
(INFN Trieste),
M. Marisaldi, F. Fuschino, C. Labanti, A. Bulgarelli, F. Gianotti, M.
Trifoglio, G. Di Cocco (INAF/IASF Bologna), M. Galli (ENEA), E. Del Monte,
I. Donnarumma, Y. Evangelista, M. Feroci, F. Lazzarotto, L. Pacciani,
P. Soffitta,
E. Costa, I. Lapshov, M. Rapisarda, A. Argan, G. Piano, G.
Pucella, S. Sabatini, E. Striani, A. Trois, V. Vittorini
(INAF/IASF Roma), A. Chen, S. Mereghetti, P. Caraveo, F.
Perotti (INAF/IASF Milano), A. Pellizzoni, M. Pilia (INAF/OA Cagliari),
F. D'Ammando, S. Vercellone (INAF/IASF Palermo), G. Barbiellini, E. Moretti,
E. Vallazza (INFN Trieste), A. Morselli, P. Picozza (INFN Roma-2),
M. Prest (Universita` dell'Insubria), P. Lipari, D. Zanello (INFN Roma-1),
P.W. Cattaneo, A. Rappoldi (INFN Pavia), S. Cutini, C. Pittori, F. Verrecchia,
P. Santolamazza, F. Lucarelli and P. Giommi (ASDC), L. Salotti (ASI) report:
The Gamma-Ray Imaging Detector (GRID) on board AGILE detected the long
bright GRB 100724B (Bhat, GCN 10977; Tanaka et al., GCN 10978;
Golenetskii et al., GCN 10981, Marisaldi et al., GCN 10994)
in the energy range 25 - 500 MeV with a statistical significance
larger than 9 sigma.
The gamma-ray emission observed by the AGILE-GRID instrument lasted
about 100 seconds, and two peaks are evident in the lightcurve
consistent with the behaviour reported by Fermi LAT
(the MCAL and GRID preliminary lightcurves are available at
http://www.asdc.asi.it/images/GRB100724B_lc.gif ).
The total fluence above 25 MeV during this time interval is
F = 0.2+/-0.1 ph/cm2 .
A preliminary estimate of the gamma-ray spectral photon index is
alpha= 2.2 +/-0.3.
GRB 100724B turns out to be the brightest GRB detected by AGILE
above 100 MeV during its operations in space.
A plot showing the distance between the GRB position and the AGILE
boresight as a function of time can be retrieved at
http://www.asdc.asi.it/images/GRB_100724B_distance2.png .
This message may be cited.
- 1010.4601 from 25 Oct 10
Sylvain Guiriec et al.: Detection of a Thermal Spectral Component in the Prompt Emission of GRB 100724B
Observations of GRB 100724B with the Fermi Gamma-Ray Burst Monitor (GBM) find that the spectrum is dominated by the typical Band functional
form, which is usually taken to represent a non-thermal emission component, but also includes a very significant thermal spectral contribution.
The simultaneous observation of the thermal and non-thermal components allows us to confidently identify the two emission components. The fact
that these seem to vary independently favors the idea that the thermal component is of photospheric origin while the dominant non-thermal
emission occurs at larger radii. Our results imply either a very high efficiency for the non-thermal process, or a very small size of the
region at the base of the flow, both quite challenging for the standard fireball model. These problems are resolved if the jet is initially
highly magnetized and has a substantial Poynting flux.
- 1109.3018 from 15 Sep 11
E. Del Monte et al.: The AGILE observations of the hard and bright GRB 100724B
The observation of Gamma Ray Bursts (GRBs) in the gamma-ray band has been advanced by the AGILE and Fermi satellites after the era of the
Compton Gamma-Ray Observatory. AGILE and Fermi are showing that the GeV-bright GRBs share a set of common features, particularly the high
fluence from the keV up to the GeV energy bands, the high value of the minimum Lorentz factor, the presence of an extended emission of
gamma-rays, often delayed with respect to lower energies, and finally the possible presence of multiple spectral components. GRB 100724B,
localised in a joint effort by Fermi and the InterPlanetary Newtork, is the brightest burst detected in gamma-rays so far by AGILE.
Characteristic features of GRB 100724B are the simultaneous emissions at MeV and GeV, without delayed onset nor time lag as shown by the
analysis of the cross correlation function, and the significant spectral evolution in hard X-rays over the event duration. In this paper we
show the analysis of the AGILE data of GRB 100724B and we discuss its features in the context of the bursts observed so far in gamma-rays and
the recently proposed models.
- 1308.2819 from 14 Aug 13
Rupal Basak et al.: A lingering non-thermal component in the GRB prompt emission: predicting GeV emission from the MeV spectrum
The high energy GeV emission of gamma-ray bursts (GRBs), detected by \emph{Fermi}/LAT, has a significantly different morphology compared to the
lower energy MeV emission, detected by \emph{Fermi}/GBM. Though the late time GeV emission is believed to be synchrotron radiation produced via
an external shock, this emission as early as the prompt phase is puzzling. Meaningful connection between these two emissions can be drawn only
by an accurate description of the prompt MeV spectrum. We perform a time-resolved spectroscopy of the GBM data of long GRBs having significant
GeV emission, using a model consisting of 2 blackbodies and a power-law. We examine in detail the evolution of the spectral components and
found that GRBs having high GeV emission (GRB 090902B and GRB 090926A) have a delayed onset of the power-law component, in the GBM spectrum,
which lingers at the later part of the prompt emission. This behaviour mimics the flux evolution in LAT. In contrast, bright GBM GRBs with an
order of magnitude lower GeV emission (GRB 100724B and GRB 091003) show a coupled variability of the total and the power-law flux. Further, by
analyzing the data for a set of 17 GRBs, we find a strong correlation between the power-law fluence in the MeV and the LAT fluence (Pearson
correlation: r=0.88 and Spearman correlation: $\rho=0.81$). We demonstrate that this correlation is not influenced by the correlation between
the total and the power-law fluences at a confidence level of 2.3$\sigma$. We speculate the possible radiation mechanisms responsible for the
correlation.
- 1412.3342 from 11 Dec 14
Qing-Wen Tang et al.: Measuring the bulk Lorentz factors of gamma-ray bursts with Fermi
Gamma-ray bursts (GRBs) are powered by ultra-relativistic jets. Usually a minimum value of the Lorentz factor of the relativistic bulk motion
is obtained based on the argument that the observed high energy photons ($\gg {\rm MeV}$) can escape without suffering from absorption due to
pair production. The exact value, rather than a lower limit, of the Lorentz factor can be obtained if the spectral cutoff due to such
absorption is detected. With the good spectral coverage of the Large Area Telescope (LAT) on {\em Fermi}, measurements of such cutoff become
possible, and two cases (GRB 090926A and GRB 100724B) have been reported to have high-energy cutoffs or breaks. We systematically search for
such high energy spectral cutoffs/breaks from LAT and GBM observations of the prompt emission of GRBs detected since August 2011. Seven more
GRBs are found to have cutoff-like spectral feature at energies of $\sim20-300$ MeV. Assuming that these cutoffs are caused by pair-production
absorption within the source, the bulk Lorentz factors of these GRBs are obtained. We further find that the Lorentz factors are correlated with
the isotropic gamma-ray luminosity of the bursts, indicating that more powerful GRB jets move faster.
- 1501.0508 from 22 Jan 15
Yunguo Jiang et al.: GRB Spectra in the complex of synchrotron and Compton processes
Under the steady state condition, the spectrum of electrons is investigated by solving the continuity equation under the complex radiation of
both the synchrotron and Compton processes. The resulted GRB spectrum is a broken power law in both the fast and slow cooling phases. On the
basis of this electron spectrum, the spectral indices of the Band function in four different phases are presented. In the complex radiation
frame, the detail investigation on physical parameters reveals that both the reverse shock photosphere model and the forward shock with strong
coupling model can answer the $\alpha \sim -1$ problem. A possible marginal to fast cooling phase transition in GRB 080916C is discussed. The
time resolved spectra in different pulses of GRB 100724B, GRB 100826A and GRB 130606B are investigated. We found that the flux is proportional
to the peak energy in almost all pulses. The phases for different pulses are determined according to the spectral index revolution. We found
the strong correlations between spectral indices and the peak energy in GRB 100826A, which can be explained by the Compton effect in the fast
cooling phase. However, the complex scenario predicts a steeper index for the injected electrons, which challenges the acceleration mechanism
in GRBs.
- 1506.02926 from 10 Jun 15
Björn Ahlgren et al.: Confronting GRB prompt emission with a model for subphotospheric dissipation
The origin of the prompt emission in gamma-ray bursts (GRBs) is still an unsolved problem and several different mechanisms have been suggested.
Here we fit Fermi GRB data with a photospheric emission model which includes dissipation of the jet kinetic energy below the photosphere. The
resulting spectra are dominated by Comptonization and contain no significant contribution from synchrotron radiation. In order to fit to the
data we span a physically motivated part of the model's parameter space and create DREAM ($\textit{Dissipation with Radiative Emission as A
table Model}$), a table model for ${\scriptsize XSPEC}$. We show that this model can describe different kinds of GRB spectra, including GRB
090618, representing a typical Band function spectrum, and GRB 100724B, illustrating a double peaked spectrum, previously fitted with a
Band+blackbody model, suggesting they originate from a similar scenario. We suggest that the main difference between these two types of bursts
is the optical depth at the dissipation site.
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