Gamma-ray Burst 050819

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 19 Aug 05 16:25:22 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     151131,   Seg_Num: 0
GRB_RA:          358.735d {+23h 54m 56s} (J2000),
                 358.807d {+23h 55m 14s} (current),
                 358.098d {+23h 52m 24s} (1950)
GRB_DEC:         +24.854d {+24d 51' 13"} (J2000),
                 +24.885d {+24d 53' 05"} (current),
                 +24.575d {+24d 34' 31"} (1950)
GRB_ERROR:       4.00 [arcmin radius, statistical only]
GRB_INTEN:       116085 [cnts]    Image_Peak=1308 [image_cnts]
TRIGGER_DUR:     26.880 [sec]
TRIGGER_INDEX:   463     E_range: 15-50 keV
BKG_INTEN:       263793 [cnts]
BKG_TIME:        58928.00 SOD {16:22:08.00} UT
BKG_DUR:         64 [sec]
GRB_DATE:        13601 TJD;   231 DOY;   05/08/19
GRB_TIME:        59035.13 SOD {16:23:55.13} UT
GRB_PHI:         -114.01 [deg]
GRB_THETA:        20.63 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     9.94 [sigma]
IMAGE_SIGNIF:    8.79 [sigma]
MERIT_PARAMS:     +1  +0  +0  +5  +1  +0  +0  +0 +67  +1
SUN_POSTN:       149.00d {+09h 56m 00s}  +12.59d {+12d 35' 11"}
SUN_DIST:        132.57 [deg]
MOON_POSTN:      329.32d {+21h 57m 17s}  -16.54d {-16d 32' 35"}
MOON_DIST:        50.42 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      106.99,-36.26 [deg] galactic lon,lat of the burst (or
+transient)
ECL_COORDS:        9.32, 23.18 [deg] ecliptic lon,lat of the burst (or
+transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.
COMMENTS:        This is a rate trigger.
COMMENTS:        A point_source was found.
COMMENTS:        This does not match any source in the on-board catalog.
COMMENTS:        This does not match any source in the ground catalog.
COMMENTS:        This is a GRB.

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 19 Aug 05 16:25:22 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     151131,   Seg_Num: 0
GRB_RA:          358.735d {+23h 54m 56s} (J2000),
                 358.807d {+23h 55m 14s} (current),
                 358.098d {+23h 52m 24s} (1950)
GRB_DEC:         +24.854d {+24d 51' 13"} (J2000),
                 +24.885d {+24d 53' 05"} (current),
                 +24.575d {+24d 34' 31"} (1950)
GRB_ERROR:       4.00 [arcmin radius, statistical only]
GRB_INTEN:       116085 [cnts]    Image_Peak=1308 [image_cnts]
TRIGGER_DUR:     26.880 [sec]
TRIGGER_INDEX:   463     E_range: 15-50 keV
BKG_INTEN:       263793 [cnts]
BKG_TIME:        58928.00 SOD {16:22:08.00} UT
BKG_DUR:         64 [sec]
GRB_DATE:        13601 TJD;   231 DOY;   05/08/19
GRB_TIME:        59035.13 SOD {16:23:55.13} UT
GRB_PHI:         -114.01 [deg]
GRB_THETA:        20.63 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     9.94 [sigma]
IMAGE_SIGNIF:    8.79 [sigma]
MERIT_PARAMS:     +1  +0  +0  +5  +1  +0  +0  +0 +67  +1
SUN_POSTN:       149.00d {+09h 56m 00s}  +12.59d {+12d 35' 11"}
SUN_DIST:        132.57 [deg]
MOON_POSTN:      329.32d {+21h 57m 17s}  -16.54d {-16d 32' 35"}
MOON_DIST:        50.42 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      106.99,-36.26 [deg] galactic lon,lat of the burst (or
+transient)
ECL_COORDS:        9.32, 23.18 [deg] ecliptic lon,lat of the burst (or
+transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.
COMMENTS:        This is a rate trigger.
COMMENTS:        A point_source was found.
COMMENTS:        This does not match any source in the on-board catalog.
COMMENTS:        This does not match any source in the ground catalog.
COMMENTS:        This is a GRB.

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 19 Aug 05 16:26:24 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     151131,   Seg_Num: 0
POINT_RA:        358.729d {+23h 54m 55s} (J2000)
POINT_DEC:       +24.849d {+24d 50' 55"} (J2000)
GRB_DATE:        13601 TJD;   231 DOY;   05/08/19
GRB_TIME:        59175.82 SOD {16:26:15.82} UT
COUNTS:          17    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        1    Max_iter_allowed= 4
ERROR_CODE:      1
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        No source found in the image.

red DSS finding chart ps-file

GCN/SWIFT NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 19 Aug 05 16:29:44 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     151131,   Seg_Num: 0
GRB_RA:          358.735d {+23h 54m 56s} (J2000),
                 358.807d {+23h 55m 14s} (current),
                 358.098d {+23h 52m 24s} (1950)
GRB_DEC:         +24.854d {+24d 51' 13"} (J2000),
                 +24.885d {+24d 53' 05"} (current),
                 +24.575d {+24d 34' 31"} (1950)
GRB_DATE:        13601 TJD;   231 DOY;   05/08/19
GRB_TIME:        59035.13 SOD {16:23:55.13} UT
TRIGGER_INDEX:   463
GRB_PHI:         -114.01 [deg]
GRB_THETA:        20.63 [deg]
DELTA_TIME:      39.00 [sec]
TRIGGER_DUR:     26.880 [sec]
LC_URL:          sw00151131000msb.lc
SUN_POSTN:       149.00d {+09h 56m 00s}  +12.59d {+12d 35' 11"}
SUN_DIST:        132.57 [deg]
MOON_POSTN:      329.32d {+21h 57m 17s}  -16.54d {-16d 32' 35"}
MOON_DIST:        50.42 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      106.99,-36.26 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        9.32, 23.18 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-BAT GRB Lightcurve.
COMMENTS:
COMMENTS:        The next comments were copied from the BAT_POS Notice:
COMMENTS:        This is a rate trigger.
COMMENTS:        A point_source was found.
COMMENTS:        This does not match any source in the on-board catalog.
COMMENTS:        This does not match any source in the ground catalog.
COMMENTS:        This is a GRB.

GCN notice #3826
M. De Pasquale (MSSL), S. Barthelmy (GSFC), A.P. Beardmore (U Leicester), D. Burrows (PSU), M. Chester (PSU), A. Cucchiara (PSU), J. Cummings (GSFC/NRC), N. Gehrels (GSFC), M.R. Goad (U Leicester), J. Kennea (PSU), H. Krimm (GSFC/USRA), S.T. Holland (GSFC/USRA), S. Hunsberger (PSU), F. Marshall (GSFC), C. Markwardt (GSFC/UMD), J.P. Osborne (U Leicester), K.L. Page (U Leicester), D. Palmer (LANL), A. Parsons (GSFC), P. Roming (PSU), T. Sakamoto (GSFC), M. Still (GSFC) on behalf of the Swift team:
At 16:23:55 UT, Swift-BAT triggered and located GRB050819 (trigger 151131). The BAT on-board calculated location is RA,Dec 358.735d,+24.854d {23h 54m 56s,+24d 51' 13"} (J2000), with an uncertainty of 2 arcmin (radius, 90% containment, stat+sys). The BAT light curve shows a very broad shallow peak of about 40 seconds duration. The peak count rate was ~400 counts/sec (15-350 keV) at ~10 seconds after the trigger.
The spacecraft slewed immediately and the XRT began taking data at 16:26:15.8, 141 seconds after the BAT trigger. There were not enough counts in the first 2.5 s image for a successful on-board centroid. However, the light-curve shows evidence for a decaying X-ray source in the field of view and the spectrum appears consistent with that of a GRB.
The UVOT began observing the position of the trigger at 16:26:13.5 UT, 138 s after the BAT trigger. In a 100 s V-band image, no new source is detected with respect to the DSS down to a 5 sigma upper limit of 18.1 mag. The estimated extinction in this direction is A_V ~ 0.4 magnitudes. The UVOT image gives 50% coverage assuming a BAT error circle of 2 arcmin radius.
GCN notice #3827
J.A. Kennea, D.N. Burrows (PSU), K. Page (U. Leceister) report on behalf of the Swift/XRT team:
We have analysed the ground data from GRB 050819 (BAT Trigger #151131). We find a previously uncatalogued, fading X-ray source at the following coordinates:
```
RA(J2000):  23:55:01.2
Dec(J2000): 24:51:36.5
```
with a uncertainty of 8 arcseconds radius (90% containment). This position is 69 arcseconds from the BAT position reported in GCN 3826.
GCN notice #3828
S. Barthelmy (GSFC), L. Barbier (GSFC), J. Cummings (GSFC/NRC), D. Hullinger (GSFC/UMD), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), F. Marshall (GSFC), A. Smale (NASA HQ), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), J. Tueller (GSFC) on behalf of the Swift-BAT team:
Using the full data set from the recent telemetry downlink, we report further analysis of Swift-BAT GRB 050819 (trigger #151131) (De Pasquale, et al., GCN 3826). The ground-analysis position is RA,Dec 358.757, +24.874 (J2000) with an uncertainty of 2 arcmin (radius, 90%, stat+sys). This is 50 arcseconds from the XRT ground- calculated position reported by Kennea et al. in GCN Circ. 3827.
The light curve shows a long weak peak with indistinct structure from T-12 to T+37 seconds. T90 is 36 +/- 4 sec. Fitting a simple power law over the interval from T-2 to T+34 sec, the photon index is 2.6 +/- 0.3 with a fluence of 4.2 +/- 0.8 x 10^-7 erg/cm^2 in the 15-350 keV band (90% c.l.). The peak flux in a 1-sec wide window starting at T+9.5 seconds is 0.46 +/- 0.14 ph/cm^2/sec (15-350 keV).
GCN notice #3831
I. Bikmaev, A. Galeev, N. Sakhibullin (KSU/AST), R. Burenin, M. Pavlinsky, R. Sunyaev (IKI), I. Khamitov, Z. Aslan (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.),
report:
We have observed the error box of GRB 050819 (S. Barthelmy, et al., GCN 3790) with the Russian-Turkish 1.5-m telescope (Bakirlitepe, TUBITAK National Observatory,Turkey). We made a series of 30s and 100s exposures in R between UT 18:35 - 22:15, August 19, 2005, under full Moon conditions. We have found no variable source brighter than magnitude R ~= 21.6
This message may be cited.
GCN notice #3832
K.L. Page (U. Leicester), J.A. Kennea, D.N. Burrows (PSU), M. Ajello (MPE), M. Trippico (GSFC-SSAI) report on behalf of the Swift/XRT team:
We have analysed the XRT data for GRB050819 (BAT Trigger 151131), between 146 and 3.7e4 seconds after the trigger. As previously reported by Kennea et al in GCN 3827, there is an uncatalogued, fading X-ray source in the field of view. The refined coordinates for this burst are
```
RA(J2000):  23:55:01.37
Dec(J2000): 24:51:31.28
```
with an uncertainty of 8 arcseconds radius (90% containment). This is 5.7 arcseconds from the XRT position given in GCN 3827 and 75 arcseconds from the initial BAT position reported in GCN 3826.
XRT observations began in Windowed Timing mode 146 seconds after the trigger, switching down to Photon Counting mode 58 seconds later. The light-curve shows a steep initial decline with a decay index of alpha = 3.7 +/- 0.3, breaking to a very flat slope of < 0.28 at around 850 seconds.
The spectrum of the early afterglow shows no evidence for excess NH above the Galactic value (4.6e20 cm^-2), and can be well fitted by a power-law with Gamma = 2.2 +/- 0.2. Between 146 and 203 seconds, the unabsorbed 0.3-10 keV flux was 1.62e-10 erg cm^-2 s^-1.
If the light-curve continues without a further break, the predicted count-rate at 24 hours will be 0.009 counts s^-1, corresponding to 0.3-10 keV flux of 3.2e-13 erg cm^-2 s^-1 (unabsorbed).
New/revised redshift from the TOUGH project, in particular: 1205.3162 1205.3490 1205.3779 1205.4036

Back to JG's homepage

Jochen Greiner, last update: 08-Jul-2012 [Disclaimer]