Gamma-ray Burst 070805

(All information courtesy of the instrument teams.)

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 05 Aug 07 19:56:23 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     287088,   Seg_Num: 0
GRB_RA:          245.043d {+16h 20m 10s} (J2000),
                 245.207d {+16h 20m 50s} (current),
                 243.969d {+16h 15m 53s} (1950)
GRB_DEC:         -59.945d {-59d 56' 40"} (J2000),
                 -59.963d {-59d 57' 44"} (current),
                 -59.825d {-59d 49' 29"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       17769 [cnts]    Image_Peak=441 [image_cnts]
TRIGGER_DUR:     4.096 [sec] 
TRIGGER_INDEX:   298     E_range: 25-100 keV
BKG_INTEN:       152152 [cnts]
BKG_TIME:        71685.86 SOD {19:54:45.86} UT
BKG_DUR:         40 [sec]
GRB_DATE:        14317 TJD;   217 DOY;   07/08/05
GRB_TIME:        71745.44 SOD {19:55:45.44} UT
GRB_PHI:         -32.49 [deg]
GRB_THETA:        35.66 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     11.31 [sigma]
IMAGE_SIGNIF:    9.19 [sigma]
MERIT_PARAMS:     +1  +0  +0  +2  +2  +2  +0  +1 +41  +1 
SUN_POSTN:       135.49d {+09h 01m 57s}  +16.91d {+16d 54' 23"}
SUN_DIST:        114.42 [deg]   Sun_angle= -7.3 [hr] (East of Sun)
MOON_POSTN:       38.23d {+02h 32m 55s}  +20.02d {+20d 01' 27"}
MOON_DIST:       135.69 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:      326.42, -6.97 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      254.48,-37.84 [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.  
COMMENTS:        This trigger occurred at longitude,latitude = 119.89,2.73 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 05 Aug 07 19:59:16 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     287088,   Seg_Num: 0
GRB_RA:          245.043d {+16h 20m 10s} (J2000),
                 245.207d {+16h 20m 50s} (current),
                 243.969d {+16h 15m 53s} (1950)
GRB_DEC:         -59.945d {-59d 56' 40"} (J2000),
                 -59.963d {-59d 57' 44"} (current),
                 -59.825d {-59d 49' 29"} (1950)
GRB_DATE:        14317 TJD;   217 DOY;   07/08/05
GRB_TIME:        71745.44 SOD {19:55:45.44} UT
TRIGGER_INDEX:   298
GRB_PHI:         -32.49 [deg]
GRB_THETA:        35.66 [deg]
DELTA_TIME:      -37.00 [sec]
TRIGGER_DUR:     4.096 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     11.31 [sigma]
IMAGE_SIGNIF:    9.19 [sigma]
LC_URL:          sw00287088000msb.lc
SUN_POSTN:       135.49d {+09h 01m 57s}  +16.91d {+16d 54' 21"}
SUN_DIST:        114.41 [deg]   Sun_angle= -7.3 [hr] (East of Sun)
MOON_POSTN:       38.26d {+02h 33m 02s}  +20.03d {+20d 02' 03"}
MOON_DIST:       135.71 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:      326.42, -6.97 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      254.48,-37.84 [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 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.  
COMMENTS:        This trigger occurred at longitude,latitude = 119.89,2.73 [deg].

GCN Circular #6708
A. M. Parsons (GSFC), S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), V. La Parola (INAF-IASFPA), C. B. Markwardt (CRESST/GSFC/UMD), D. M. Palmer (LANL), M. Stamatikos (NASA/ORAU), R. L. C. Starling (U Leicester), E. Troja (INAF-IASFPA), T. N. Ukwatta (GSFC/GWU), D. E. Vanden Berk (PSU), S. D. Vergani (DIAS-DCU) and H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team:
At 19:55:45 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 070805 (trigger=287088). The BAT on-board calculated location is RA, Dec 245.043, -59.945 which is
```
   RA(J2000)  =  16h 20m 10s
   Dec(J2000) = -59d 56' 40"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows two peaks, the first is ~5 sec in duration and the second peak is broader and weaker ending around T+40 sec. The peak count rate was ~500 counts/sec (15-350 keV), at ~2 sec after the trigger.
Because of an Earth limb constraint, the spacecraft did not slew promptly to the BAT position, and so there are no immediate XRT or UVOT data products to analyze. The burst will come out of constraint at T+31 minutes.
Burst Advocate for this burst is A. M. Parsons (parsons AT milkyway.gsfc.nasa.gov). 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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 05 Aug 07 20:29:04 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     287088,   Seg_Num: 0
POINT_RA:        245.007d {+16h 20m 02s} (J2000)
POINT_DEC:       -59.932d {-59d 55' 54"} (J2000)
IMG_START_DATE:  14317 TJD;   217 DOY;   07/08/05
IMG_START_TIME:  73718.97 SOD {20:28:38.97} UT,   1973.5 [sec] since BAT Trigger Time
COUNTS:          22    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        4    Max_iter_allowed= 4
ERROR_CODE:      2
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        Algorithm did not converge; too many interations.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 05 Aug 07 20:33:33 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     287088,   Seg_Num: 0
POINT_RA:        245.001d {+16h 20m 00s} (J2000)
POINT_DEC:       -59.930d {-59d 55' 48"} (J2000)
POINT_ROLL:      261.719d
IMG_START_DATE:  14317 TJD;   217 DOY;   07/08/05
IMG_START_TIME:  73722.63 SOD {20:28:42.63} UT,   1977.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.472
N_STARS:         190
X_OFFSET:        303 [pixels]
Y_OFFSET:        510 [pixels]
X_MAX:           1262 [pixels]
Y_MAX:           1469 [pixels]
DET_THRESH:      20
PHOTO_THRESH:    12
SL_URL:          sw00287088000msufc1977.fits
SUN_POSTN:       135.51d {+09h 02m 03s}  +16.90d {+16d 53' 57"}
SUN_DIST:        114.38 [deg]   Sun_angle= -7.3 [hr] (East of Sun)
MOON_POSTN:       38.59d {+02h 34m 23s}  +20.15d {+20d 09' 08"}
MOON_DIST:       135.95 [deg]
MOON_ILLUM:      50 [%]
GAL_COORDS:      326.42, -6.95 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      254.45,-37.83 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 05 Aug 07 20:34:05 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     287088,   Seg_Num: 0
POINT_RA:        245.001d {+16h 20m 00s} (J2000)
POINT_DEC:       -59.930d {-59d 55' 48"} (J2000)
POINT_ROLL:      261.719d
IMG_START_DATE:  14317 TJD;   217 DOY;   07/08/05
IMG_START_TIME:  73722.63 SOD {20:28:42.63} UT,   1977.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.472
N_STARS:         190
X_OFFSET:        303 [pixels]
Y_OFFSET:        510 [pixels]
X_MAX:           1262 [pixels]
Y_MAX:           1469 [pixels]
DET_THRESH:      20
PHOTO_THRESH:    12
SL_URL:          sw00287088000msufc1977.fits
SUN_POSTN:       135.51d {+09h 02m 03s}  +16.90d {+16d 53' 57"}
SUN_DIST:        114.38 [deg]   Sun_angle= -7.3 [hr] (East of Sun)
MOON_POSTN:       38.60d {+02h 34m 24s}  +20.15d {+20d 09' 15"}
MOON_DIST:       135.95 [deg]
MOON_ILLUM:      50 [%]
GAL_COORDS:      326.42, -6.95 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      254.45,-37.83 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 05 Aug 07 20:34:28 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     287088,   Seg_Num: 0
POINT_RA:        245.001d {+16h 20m 00s} (J2000)
POINT_DEC:       -59.930d {-59d 55' 48"} (J2000)
ROLL:            261.719d
IMG_START_DATE:  14317 TJD;   217 DOY;   07/08/05
IMG_START_TIME:  73722.63 SOD {20:28:42.63} UT,   1977.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     208038524
X_OFFSET:        622 [pixels]
Y_OFFSET:        829 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       782
Y_GRB_POS:       989
BINNING_INDEX:   1
IM_URL:          sw00287088000msuni1977.fits
SUN_POSTN:       135.51d {+09h 02m 03s}  +16.90d {+16d 53' 57"}
SUN_DIST:        114.38 [deg]   Sun_angle= -7.3 [hr] (East of Sun)
MOON_POSTN:       38.60d {+02h 34m 25s}  +20.16d {+20d 09' 20"}
MOON_DIST:       135.95 [deg]
MOON_ILLUM:      50 [%]
GAL_COORDS:      326.42, -6.95 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      254.45,-37.83 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 05 Aug 07 20:34:52 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     287088,   Seg_Num: 0
POINT_RA:        245.001d {+16h 20m 00s} (J2000)
POINT_DEC:       -59.930d {-59d 55' 48"} (J2000)
ROLL:            261.719d
IMG_START_DATE:  14317 TJD;   217 DOY;   07/08/05
IMG_START_TIME:  73722.63 SOD {20:28:42.63} UT,   1977.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     208038524
X_OFFSET:        622 [pixels]
Y_OFFSET:        829 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       782
Y_GRB_POS:       989
BINNING_INDEX:   1
IM_URL:          sw00287088000msuni1977.fits
SUN_POSTN:       135.51d {+09h 02m 03s}  +16.90d {+16d 53' 56"}
SUN_DIST:        114.38 [deg]   Sun_angle= -7.3 [hr] (East of Sun)
MOON_POSTN:       38.61d {+02h 34m 26s}  +20.16d {+20d 09' 25"}
MOON_DIST:       135.95 [deg]
MOON_ILLUM:      50 [%]
GAL_COORDS:      326.42, -6.95 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      254.45,-37.83 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_sources_image.fits.gz file does not exist; skipping the attachment.

GCN Circular #6709
D. E. Vanden Berk (PSU), P. Kuin (MSSL), F. E. Marshall (NASA/GSFC), and A. M. Parsons (GSFC) report on behalf of the Swift-UVOT team:
UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 1977 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The overlap of the sub-image and the BAT error circle is uncertain at this time. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the region. No correction has been made for the extinction of E(B-V)=0.202.
GCN Circular #6710
V. La Parola, J. Kennea, E. Troja, V. Mangano, B. Sbarufatti on behalf of the Swift team.
We have analysed the first 2.3 ks of the XRT observation of GRB070805 (Parsons et al., GCN 6708). Due to Earth limb constraint the XRT began observing the GRB location 33 min after the trigger, at 20:28:48 UT. No sources are visible in this first orbit of data, with an upper limit to the unabsorbed flux of 2.4e-13 erg/s/cm2. We are waiting for more data for further analysis.
This is an official product of the Swift-XRT team
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GCN Circular #6711
M. Stamatikos (GSFC/ORAU), L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS), J. Tueller (GSFC), T. Ukwatta (GWU) (i.e. the Swift-BAT team):
Using the data set from T-120 to T+182 sec from the recent telemetry downlink, we report further analysis of BAT GRB 070805 (trigger #287088) (Parsons, et al., GCN Circ. 6708). The BAT ground-calculated position is RA, Dec = 245.057, -59.957 deg, which is
```
   RA(J2000)  =  16h 20m 13.8s 
   Dec(J2000) = -59d 57' 26" 
```
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 60%.
The mask-weighted light curve shows two overlapping FRED-like peaks, the first starting at ~T_zero and the second ending at ~T+35 sec. We note that the spacecraft slewed to a pre-planned target at T+135 sec. During the slew the burst location left the BAT FOV at T+182 sec, and as such, we can not determine if there as any burst activity beyond T+182 sec. T90 (15-350 keV) is 31.0 +- 1.0 sec (estimated error including systematics).
The time-averaged spectrum from T-0.6 to T+35.7 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.84 +- 0.20. The fluence in the 15-150 keV band is 7.2 +- 0.8 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+3.23 sec in the 15-150 keV band is 0.7 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
GCN Circular #6712
P. Schady and A.M. Parsons (GSFC) report on behalf of the Swift UVOT team
The Swift/UVOT observed the field of GRB070805 (trigger=287088) starting 33 minutes after the BAT trigger (Parsons et al. 2007, GCN Circ.6708). We do not find any new source in the UVOT observations within the BAT error circle or in the whole of the UVOT field of view, which we note is a very crowded field.
The 5-sigma upper limits in the co-added frames are listed below:
```
Filter   Tmid   Exposure   Magnitude
          (s)    (s)        (5-sigma UL)
white    3267   333         > 20.2
v        2825   274         > 18.5
b        3441   274         > 19.5
u        3287   274         > 19.2
uvw1     3133   274         > 19.0
uvm2     2979   274         > 18.8
uvw2     3384   452         > 19.4
```
where Tmid is the weighted mean team of the coadded exposure. The values quoted above are not corrected for the expected Galactic extinction corresponding to a reddening of E(B-V) = 0.202 mag in the direction of the burst (Schlegel et al. 1998).
GCN Circular #6716
V. La Parola, P. Schady, F.E. Marshall, S. T. Holland and A. M. Parsons, E. Troja, J. Kennea report on behalf of the Swift team
We have analysed the XRT and UVOT observations of GRB070805 (Parsons et al., GCN 6708).
The XRT observed the BAT position twice, with 2.3 and 7.7 ksec exposure times. We find a faint source (estimated unabsorbed flux: 3.4e-13 erg/s/cm2) within the BAT error circle, at
```
RA= 16 20 02.8 (245.01175)
Dec= -59 57 34.8 (-59.959657)
```
(4 arcsec error radius, 90% confidence) that is 82 arcsec from the BAT position (Stamatikos et al, GCN 6711) This source does not show any sign of decay, its count rate being consistent between the two observations. The source is too faint to allow for any detailed spectral or temporal analysis.
A second, fainter source is detected only in the second observation, at
```
RA= 16 20 16.8 (245.069937)
Dec= -59 57 12.7 (-59.95352)
```
(4.7 arcsec error radius, 90% confidence) The estimated unabsorbed flux is 1.13e-13 erg/s/cm2.
At present, neither of these sources can be confidently associated with the GRB afterglow.
On further inspection of the UVOT observations, an uncatalogued source is detected at the position of the first XRT source. This source was initially unidentified (GCN Circ. 6712) due to the density of the field and size of the BAT error circle. The source is detected in the white band filter at more than 3 sigma with an estimated magnitude of 20.1+/-0.2, and is marginally detected in the V, B and U filters. The refined UVOT coordinates of this source are
```
RA = 16 20 03.11 (245.0131)
Dec = -59 57 34.9 (-59.9597)
```
with an uncertainty of 0.7 arcseconds. There is little evidence for variability in the limited data currently available. Observations are ongoing.
GCN Circular #6763
P. Schady and A.M. Parsons report on behalf of the Swift UVOT team
The Swift/UVOT re-observed the field of GRB070805 on 2007-08-07 at 14:36 UT, 1.8 days after the BAT trigger (GCN Circ. 6708). The uncatalogued source detected by UVOT in previous white band observations (GCN Circ. 6716) is detected and does not show any sign of decay. It is therefore unlikely that this source is the afterglow of GRB070805.

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Jochen Greiner, last update: 21-Aug-2007 [Disclaimer]