Gamma-ray Burst 081017

(All information courtesy of the instrument teams.)

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 17 Oct 08 23:43:57 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     331964,   Seg_Num: 0
GRB_RA:          230.180d {+15h 20m 43s} (J2000),
                 230.317d {+15h 21m 16s} (current),
                 229.403d {+15h 17m 37s} (1950)
GRB_DEC:         -32.815d {-32d 48' 53"} (J2000),
                 -32.846d {-32d 50' 46"} (current),
                 -32.635d {-32d 38' 06"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       0 [cnts]    Image_Peak=5517 [image_cnts]
TRIGGER_DUR:     320.000 [sec]   (=5.3 [min])
TRIGGER_INDEX:   20000     E_range: 15-50 keV
BKG_INTEN:       0 [cnts]
BKG_TIME:        0.00 SOD {00:00:00.00} UT
BKG_DUR:         0 [sec]
GRB_DATE:        14756 TJD;   291 DOY;   08/10/17
GRB_TIME:        85092.81 SOD {23:38:12.81} UT
GRB_PHI:         -50.47 [deg]
GRB_THETA:        22.09 [deg]
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    8.34 [sigma]
MERIT_PARAMS:     +1  +0  +0  +6  +1  -1 -100  +0 -82  +0 
SUN_POSTN:       203.14d {+13h 32m 33s}   -9.67d {-09d 40' 00"}
SUN_DIST:         34.12 [deg]   Sun_angle= -1.8 [hr] (East of Sun)
MOON_POSTN:       65.30d {+04h 21m 11s}  +26.27d {+26d 16' 13"}
MOON_DIST:       165.43 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      335.85, 20.35 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      236.33,-13.91 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is an image trigger.  (The RATE_SIGNIF & BKG_{INTEN, TIME, DUR} are undefined.)  
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.  
COMMENTS:        This trigger occurred at longitude,latitude = 194.67,9.64 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 17 Oct 08 23:46:34 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     331964,   Seg_Num: 0
GRB_RA:          230.180d {+15h 20m 43s} (J2000),
                 230.317d {+15h 21m 16s} (current),
                 229.403d {+15h 17m 37s} (1950)
GRB_DEC:         -32.815d {-32d 48' 53"} (J2000),
                 -32.846d {-32d 50' 46"} (current),
                 -32.635d {-32d 38' 06"} (1950)
GRB_DATE:        14756 TJD;   291 DOY;   08/10/17
GRB_TIME:        85092.81 SOD {23:38:12.81} UT
TRIGGER_INDEX:   20000
GRB_PHI:         -50.47 [deg]
GRB_THETA:        22.09 [deg]
DELTA_TIME:      0.00 [sec]
TRIGGER_DUR:     320.000 [sec]   (=5.3 [min])
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    8.34 [sigma]
LC_URL:          sw00331964000msb.lc
SUN_POSTN:       203.14d {+13h 32m 33s}   -9.67d {-09d 40' 03"}
SUN_DIST:         34.12 [deg]   Sun_angle= -1.8 [hr] (East of Sun)
MOON_POSTN:       65.33d {+04h 21m 18s}  +26.27d {+26d 16' 26"}
MOON_DIST:       165.40 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      335.85, 20.35 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      236.33,-13.91 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Lightcurve.  
COMMENTS:           
COMMENTS:        The next comments were copied from the BAT_POS Notice:  
COMMENTS:        This is an image 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.  
COMMENTS:        This trigger occurred at longitude,latitude = 194.67,9.64 [deg].

GCN Circular #8388
O. Godet (U Leicester), S. D. Barthelmy (GSFC), P. A. Evans (U Leicester), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL), M. Stamatikos (NASA/ORAU), T. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU) report on behalf of the Swift Team:
At 23:38:12 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 081017 (trigger=331964). This was too close to the Sun for Swift to slew to. The BAT on-board calculated location is RA, Dec 230.180, -32.815 which is
```
   RA(J2000) = 15h 20m 43s
   Dec(J2000) = -32d 48' 53"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual for an image trigger, the immediately available BAT light curve shows no obvious variation.
Due to an observing constraint, Swift cannot slew to the BAT position. There will thus be no XRT or UVOT data for this trigger.
Burst Advocate for this burst is O. Godet (og19 AT star.le.ac.uk). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)
GCN Circular #8389
P. D'Avanzo, S. Covino, L.A. Antonelli, D. Malesani, D. Fugazza, L. Calzoletti, S. Campana, G. Chincarini, M.L. Conciatore, S. Cutini, V. D'Elia, F. D'Alessio, F. Fiore, P. Goldoni, D. Guetta, C. Guidorzi, G.L. Israel, E. Maiorano, N. Masetti, A. Melandri, E. Meurs, L. Nicastro, E. Palazzi, E. Pian, S. Piranomonte, L. Stella, G. Stratta, G. Tagliaferri, G. Tosti, V.Testa, S.D. Vergani, F. Vitali report on behalf of the REM team:
The robotic 60-cm REM telescope located at La Silla (Chile) observed automatically the field of the GRB 081017 (Godet et al. GCN 8388) on Oct 17 starting about 6.5 min after the burst. Observations were carried out at high airmass. In a series of 10s and 30s exposures, at we do not see the any clear afterglow candidate inside the BAT error box down to R > 17.0 and H > 15.5 (3sigma c.l.).
GCN Circular #8390
J. Tueller (GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), O. Godet (U Leicester), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from recent telemetry downlinks, we report further analysis of BAT GRB 081017 (trigger #331964) (Godet, et al., GCN Circ. 8388). The BAT ground-calculated position is RA, Dec = 230.209, -32.790 deg which is
```
   RA(J2000)  =  15h 20m 50.1s 
   Dec(J2000) = -32d 47' 23.3" 
```
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 80%.
The mask-weighted light curve shows a broad lo-level emission with some structure starting at ~T-70 and ending around T+400 sec. The spacecraft slewed to the next pre-planned observing target at T+400 sec such that the partial coding of this burst location decreased to a small value. As such the statisitical error on the flux measurement increased to the point that we can only say there is a hint of emission out to around T+700 sec. T90 (15-350 keV) is 320 +- 50 sec (estimated error including systematics).
The time-averaged spectrum from T+0.0 to T+320.0 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.64 +- 0.23. The fluence in the 15-150 keV band is 1.4 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+0.00 sec in the 15-150 keV band is 0.07 +- 0.01 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/331964/BA/

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Jochen Greiner, last update: 18-Oct-2008 [Disclaimer]