Gamma-ray Burst 100125A

(All information courtesy of the instrument teams.)

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Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 25 Mar 10 06:36:23 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      47
TRIGGER_NUM:     291191770
GRB_RA:          327.150d {+21h 48m 36s} (J2000),
                 327.295d {+21h 49m 11s} (current),
                 326.441d {+21h 45m 46s} (1950)
GRB_DEC:         -23.917d {-23d 54' 59"} (J2000),
                 -23.869d {-23d 52' 06"} (current),
                 -24.150d {-24d 08' 57"} (1950)
GRB_ERROR:       6.47 [deg radius, statistical plus systematic]
GRB_INTEN:       422 [cnts/sec]
DATA_SIGNIF:     17.50 [sigma]
INTEG_TIME:      1.024 [sec]
GRB_DATE:        15280 TJD;    84 DOY;   10/03/25
GRB_TIME:        23768.02 SOD {06:36:08.02} UT
GRB_PHI:           0.00 [deg]
GRB_THETA:         5.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO:      0.40
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      95%  GRB
2nd_MOST_LIKELY:   4%  Generic Transient
DETECTORS:       1,0,0, 0,0,0, 1,0,0, 0,0,0, 0,0,
SUN_POSTN:         4.14d {+00h 16m 33s}   +1.79d {+01d 47' 28"}
SUN_DIST:         44.04 [deg]   Sun_angle= 2.5 [hr] (West of Sun)
MOON_POSTN:      120.23d {+08h 00m 55s}  +19.45d {+19d 26' 60"}
MOON_DIST:       154.50 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:       26.85,-48.85 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      321.26,-10.06 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 30.12,22.57 [deg].

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 25 Mar 10 06:36:36 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      59
TRIGGER_NUM:     291191770
GRB_RA:          327.200d {+21h 48m 48s} (J2000),
                 327.345d {+21h 49m 23s} (current),
                 326.492d {+21h 45m 58s} (1950)
GRB_DEC:         -23.900d {-23d 53' 59"} (J2000),
                 -23.852d {-23d 51' 07"} (current),
                 -24.133d {-24d 07' 58"} (1950)
GRB_ERROR:       6.92 [deg radius, statistical plus systematic]
GRB_INTEN:       322 [cnts/sec]
DATA_SIGNIF:     19.10 [sigma]
INTEG_TIME:      2.048 [sec]
GRB_DATE:        15280 TJD;    84 DOY;   10/03/25
GRB_TIME:        23768.02 SOD {06:36:08.02} UT
GRB_PHI:           0.00 [deg]
GRB_THETA:         5.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO:      0.51
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      95%  GRB
2nd_MOST_LIKELY:   4%  Generic Transient
DETECTORS:       1,0,0, 0,0,0, 1,0,0, 0,0,0, 0,0,
SUN_POSTN:         4.14d {+00h 16m 33s}   +1.79d {+01d 47' 29"}
SUN_DIST:         43.99 [deg]   Sun_angle= 2.5 [hr] (West of Sun)
MOON_POSTN:      120.23d {+08h 00m 56s}  +19.45d {+19d 26' 57"}
MOON_DIST:       154.46 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:       26.89,-48.89 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      321.31,-10.06 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 30.12,22.57 [deg].

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 25 Mar 10 06:36:43 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      58
TRIGGER_NUM:     291191770
GRB_RA:          329.030d {+21h 56m 07s} (J2000),
                 329.176d {+21h 56m 42s} (current),
                 328.314d {+21h 53m 15s} (1950)
GRB_DEC:         -27.320d {-27d 19' 11"} (J2000),
                 -27.271d {-27d 16' 15"} (current),
                 -27.558d {-27d 33' 27"} (1950)
GRB_ERROR:       2.15 [deg radius, statistical only]
DATA_SIGNIF:     21.10 [sigma]
DATA_INTERVAL:   2.048 [sec]
GRB_DATE:        15280 TJD;    84 DOY;   10/03/25
GRB_TIME:        23768.02 SOD {06:36:08.02} UT
GRB_PHI:         321.00 [deg]
GRB_THETA:         6.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   413 (Gnd S/W Version number)
SUN_POSTN:         4.14d {+00h 16m 33s}   +1.79d {+01d 47' 29"}
SUN_DIST:         44.46 [deg]   Sun_angle= 2.3 [hr] (West of Sun)
MOON_POSTN:      120.23d {+08h 00m 56s}  +19.45d {+19d 26' 56"}
MOON_DIST:       152.38 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:       22.24,-51.23 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      321.68,-13.84 [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 Circular #10546
A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team:
"At 06:36:08.02 UT on 25 March 2010, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 100325A (trigger 291191770/100325275).
The on-ground calculated location, using the GBM trigger data, is RA = 332.3, DEC = -28.6 (J2000 degrees, equivalent to 22h 09m, -28d 36'), with an uncertainty of 1.5 degrees (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 9 degrees.
The GBM light curve consists of a single structured pulse with a duration (T90) of 8.3 +/- 1.9 s (8-1000 keV).
The time-averaged spectrum from T0-1.664 s to T0+7.552 s is best fit by a power law function with an exponential high energy cutoff. The power law index is -0.45(+0.12/-0.11) and the cutoff energy, parameterized as Epeak, is 159.3 (+12.7/-10.8) keV (CSTAT 502 for 482 d.o.f).
The event fluence (8-1000 keV) in this time interval is (1.99 +/- 0.04)E-06 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+0.512 s in the 8-1000 keV band is 5.0 +/- 0.2 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #10548
Francesco de Palma (INFN and Universit=E0 di Bari),Takeshi Uehara=20 (Hiroshima University), Johan Bregeon (INFN Pisa), Veronique Pelassa (CNRS/IN2P3/LPTA), Jim Chiang (SLAC), Fred Piron (LPTA), Nicola Omodei (Stanford) report on behalf of the Fermi LAT collaboration:
At 06:36:08.02 UT on 25 March 2010, the Fermi Large Area Telescope (LAT) detected gamma rays from the GRB 100325A, which was triggered and=20 located by the Fermi Gamma-ray Burst Monitor (GBM) (trigger 291191770/100325.275,GCN10546). The angle of the GBM position position with respect to the LAT boresight was ~9.2 degrees at the time of the LAT detection, close to the center of the LAT field of view.
The data from the Fermi LAT shows a weak increase in the event rate that is spatially and temporally correlated with the GBM emission. It is a relatively weak detection (~>4 sigma) with 4 photons above 100 MeV within 9 seconds after the GBM trigger. The highest energy photon has an energy just above 800 MeV.
The best LAT on-ground localization is found to be (RA, Dec =3D 330.24, -26.47) (J2000) with a 90% containment radius of 0.9 deg=20 (statistical; 68% containment radius: 0.6 deg) which is consistent with=20 the GBM localization. The observed flux (100 MeV-300 GeV) from this=20 location is 1.18 +/- 0.76 e-04 (ph/cm^2/s).
Further analysis is ongoing.
The point of contact for this burst is Francesco de Palma (francesco.depalma@ba.infn.it)
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=20 many scientific institutions across France, Italy, Japan and Sweden.

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Jochen Greiner, last update: 27-Mar-2010 [Disclaimer]