Gamma-ray Burst 050922B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 22 Sep 05 15:05:01 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     156434,   Seg_Num: 0
GRB_RA:            5.800d {+00h 23m 12s} (J2000),
                   5.873d {+00h 23m 29s} (current),
                   5.162d {+00h 20m 39s} (1950)
GRB_DEC:          -5.599d {-05d 35' 55"} (J2000),
                  -5.567d {-05d 34' 01"} (current),
                  -5.876d {-05d 52' 32"} (1950)
GRB_ERROR:       4.00 [arcmin radius, statistical only]
GRB_INTEN:       0 [cnts]    Image_Peak=1873 [image_cnts]
TRIGGER_DUR:     168.000 [sec] 
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:        13635 TJD;   265 DOY;   05/09/22
GRB_TIME:        54120.25 SOD {15:02:00.25} UT
GRB_PHI:          98.27 [deg]
GRB_THETA:        37.59 [deg]
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    8.66 [sigma]
MERIT_PARAMS:     +1  +0  +0  +7  +1  -1  +0  +0 +98  +1 
SUN_POSTN:       179.73d {+11h 58m 55s}   +0.12d {+00d 07' 04"}
SUN_DIST:        171.79 [deg]
MOON_POSTN:       55.78d {+03h 43m 08s}  +23.54d {+23d 32' 27"}
MOON_DIST:        56.71 [deg]
MOON_ILLUM:      76 [%]
GAL_COORDS:      104.34,-67.45 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:        3.09, -7.44 [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.

red DSS finding chart ps-file

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 22 Sep 05 15:08:14 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     156434,   Seg_Num: 0
GRB_RA:            5.8057d {+00h 23m 13.3s} (J2000),
                   5.8787d {+00h 23m 30.8s} (current),
                   5.1679d {+00h 20m 40.2s} (1950)
GRB_DEC:          -5.6036d {-05d 36' 12.9"} (J2000),
                  -5.5719d {-05d 34' 18.8"} (current),
                  -5.8807d {-05d 52' 50.6"} (1950)
GRB_ERROR:       5.8 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       798.86 [arb]
GRB_SIGNIF:      8.48 [sigma]
GRB_DATE:        13635 TJD;   265 DOY;   05/09/22
GRB_TIME:        54462.25 SOD {15:07:42.25} UT     [Start of CCD integration]
TAM[0-3]:        327.61 237.16 261.21 243.01
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       179.73d {+11h 58m 56s}   +0.12d {+00d 06' 58"}
SUN_DIST:        171.79 [deg]
MOON_POSTN:       55.84d {+03h 43m 21s}  +23.56d {+23d 33' 21"}
MOON_DIST:        56.76 [deg]
MOON_ILLUM:      76 [%]
GAL_COORDS:      104.35,-67.45 [deg] galactic lon,lat of the burst
ECL_COORDS:        3.09, -7.45 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.
COMMENTS:        WARNING: XRT alignment calibration is on-going, and there may be
COMMENTS:        residual systematic offsets of several arcseconds not accounted for yet
COMMENTS:        by our on-board position determination algorithm.  We have increased
COMMENTS:        the estimated error circle radius to take this into account.

GCN/SWIFT NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 22 Sep 05 15:08:32 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     156434,   Seg_Num: 0
GRB_RA:            5.800d {+00h 23m 12s} (J2000),
                   5.873d {+00h 23m 29s} (current),
                   5.162d {+00h 20m 39s} (1950)
GRB_DEC:          -5.599d {-05d 35' 55"} (J2000),
                  -5.567d {-05d 34' 01"} (current),
                  -5.876d {-05d 52' 32"} (1950)
GRB_DATE:        13635 TJD;   265 DOY;   05/09/22
GRB_TIME:        54120.25 SOD {15:02:00.25} UT
TRIGGER_INDEX:   20000
GRB_PHI:          98.27 [deg]
GRB_THETA:        37.59 [deg]
DELTA_TIME:      0.00 [sec]
TRIGGER_DUR:     168.000 [sec]
LC_URL:          sw00156434000msb.lc
SUN_POSTN:       179.73d {+11h 58m 55s}   +0.12d {+00d 07' 04"}
SUN_DIST:        171.79 [deg]
MOON_POSTN:       55.78d {+03h 43m 08s}  +23.54d {+23d 32' 27"}
MOON_DIST:        56.71 [deg]
MOON_ILLUM:      76 [%]
GAL_COORDS:      104.34,-67.45 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        3.09, -7.44 [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 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.

GCN/SWIFT NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 22 Sep 05 15:09:49 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     156434,   Seg_Num: 0
POINT_RA:          5.716d {+00h 22m 52s} (J2000)
POINT_DEC:        -5.652d {-05d 39' 06"} (J2000)
POINT_ROLL:      131.944d
GRB_DATE:        13635 TJD;   265 DOY;   05/09/22
GRB_TIME:        54462.79 SOD {15:07:42.79} UT
FILTER:          3, V
BKG_MEAN:        0.000000
N_STARS:         18
X_OFFSET:        523 [pixels]
Y_OFFSET:        526 [pixels]
X_MAX:           1482 [pixels]
Y_MAX:           1485 [pixels]
DET_THRESH:      6
PHOTO_THRESH:    3
SL_URL:          sw00156434000msufc.fits
SUN_POSTN:       179.73d {+11h 58m 56s}   +0.12d {+00d 06' 58"}
SUN_DIST:        171.82 [deg]
MOON_POSTN:       55.84d {+03h 43m 21s}  +23.56d {+23d 33' 21"}
MOON_DIST:        56.86 [deg]
MOON_ILLUM:      76 [%]
GAL_COORDS:      104.09,-67.47 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        2.99, -7.46 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN/SWIFT NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 22 Sep 05 15:10:50 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     156434,   Seg_Num: 0
POINT_RA:          5.716d {+00h 22m 52s} (J2000)
POINT_DEC:        -5.652d {-05d 39' 06"} (J2000)
ROLL:            131.944d
GRB_DATE:        13635 TJD;   265 DOY;   05/09/22
GRB_TIME:        54462.79 SOD {15:07:42.79} UT
FILTER:          3, V
EXPOSURE_ID:     2275
X_OFFSET:        843 [pixels]
Y_OFFSET:        846 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1003
Y_GRB_POS:       1006
BINNING_INDEX:   1
IM_URL:          sw00156434000msuni.fits
SUN_POSTN:       179.73d {+11h 58m 56s}   +0.12d {+00d 06' 58"}
SUN_DIST:        171.82 [deg]
MOON_POSTN:       55.84d {+03h 43m 21s}  +23.56d {+23d 33' 21"}
MOON_DIST:        56.86 [deg]
MOON_ILLUM:      76 [%]
GAL_COORDS:      104.09,-67.47 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        2.99, -7.46 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN/SWIFT NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 22 Sep 05 15:11:28 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     156434,   Seg_Num: 0
POINT_RA:          5.716d {+00h 22m 52s} (J2000)
POINT_DEC:        -5.652d {-05d 39' 06"} (J2000)
ROLL:            131.944d
GRB_DATE:        13635 TJD;   265 DOY;   05/09/22
GRB_TIME:        54462.79 SOD {15:07:42.79} UT
FILTER:          3, V
EXPOSURE_ID:     2275
X_OFFSET:        843 [pixels]
Y_OFFSET:        846 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1003
Y_GRB_POS:       1006
BINNING_INDEX:   1
IM_URL:          sw00156434000msuni.fits
SUN_POSTN:       179.73d {+11h 58m 56s}   +0.12d {+00d 06' 58"}
SUN_DIST:        171.82 [deg]
MOON_POSTN:       55.84d {+03h 43m 21s}  +23.56d {+23d 33' 21"}
MOON_DIST:        56.86 [deg]
MOON_ILLUM:      76 [%]
GAL_COORDS:      104.09,-67.47 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        2.99, -7.46 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_image.fits file does not exist; skipping the attachment.

GCN/SWIFT NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 22 Sep 05 15:10:24 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     156434,   Seg_Num: 0
POINT_RA:          5.716d {+00h 22m 52s} (J2000)
POINT_DEC:        -5.652d {-05d 39' 06"} (J2000)
POINT_ROLL:      131.944d
GRB_DATE:        13635 TJD;   265 DOY;   05/09/22
GRB_TIME:        54462.79 SOD {15:07:42.79} UT
FILTER:          3, V
BKG_MEAN:        0.000000
N_STARS:         18
X_OFFSET:        523 [pixels]
Y_OFFSET:        526 [pixels]
X_MAX:           1482 [pixels]
Y_MAX:           1485 [pixels]
DET_THRESH:      6
PHOTO_THRESH:    3
SL_URL:          sw00156434000msufc.fits
SUN_POSTN:       179.73d {+11h 58m 56s}   +0.12d {+00d 06' 58"}
SUN_DIST:        171.82 [deg]
MOON_POSTN:       55.84d {+03h 43m 21s}  +23.56d {+23d 33' 21"}
MOON_DIST:        56.86 [deg]
MOON_ILLUM:      76 [%]
GAL_COORDS:      104.09,-67.47 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        2.99, -7.46 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_field_srclist.ps file does not exist; skipping the attachment.

GCN notice #4008
J. Norris (GSFC), L. Barbier (GSFC), S. Barthelmy (GSFC), P. Boyd (GSFC), D. Burrows (PSU), J. Cummings (GSFC/NRC), N. Gehrels (GSFC), S.T. Holland (GSFC/USRA), J. Kennea (PSU), H. Krimm (GSFC/USRA), F. Marshall (GSFC), O. Godet (U. Leicester), D. Palmer (LANL), T. Sakamoto (GSFC) on behalf of the Swift team:
At 15:02:00 UT, Swift-BAT triggered and located GRB050922B (trigger=156434). This was an image trigger with a 168-sec duration. The spacecraft slewed immediately after the end of the image trigger. The BAT on-board calculated location is RA,Dec 5.800d,-5.599d {00h 23m 12s,-05d 35' 55"} (J2000), with an uncertainty of 3 arcmin (radius, 90% containment, stat+sys). The TDRSS lightcurve does not show any significant emission, but these lightcurves are problematic for long image triggers. We will have to wait for the full Malindi data set (~8 hrs) to make a mask-tagged lightcurve. We note that this source is at a high galactic latitude of -67 degrees. We also note that the recent long-duration image trigger GRB 050904 was at high redshift.
XRT began observing the field at 15:07:42, 342 seconds after the BAT trigger. Onboard centroiding found a bright fading uncatalogued X-ray source in the field of view at the following coordinates:
```
RA(J2000):   0:23:13.3,
Dec(J2000): -5:36:12.9.
```
We estimate the uncertainty of this position to be 8 arcseconds (radius, 90% containment). This position is 26 arcseconds from the BAT position above.
UVOT began observing at 343 sec after the trigger. The small UVOT TDRSS image does not overlap the BAT error circle. However, the full-field UVOT source list contains only catalogued sources, in particular no source is found inside the XRT error circle. At the present time it is not possible to determine a limiting magnitude for this field. The V-band extinction in this direction is A_V = 0.12 mag.
GCN notice #4009
E.Sonoda,S.Maeno,Y.Tokunaga,M.Yamauchi (University of Miyazaki)
"We have observed the field covering the error circle of GRB 050922(GCN4008;Swift-BAT Trigger time is 15:02:00 UT) with the unfiltered CCD camera on the 30-cm telescope at University of Miyazaki. The observation was started 15:28:46 UT on Sep.22. After co-adding a set of 6 images (15:28:46 - 15:37:46 UT) of 30 sec exposures, we have compared with the USNO A2.0 catalog. Preliminary analysis shows there is no new source brighter than 16.1 mag."
GCN notice #4010
B. E. Schaefer (Louisiana State), R. Quimby (U Texas), S.A. Yost (U Mich), W. Rujopakarn (U Mich) report on behalf of the ROTSE collaboration:
ROTSE-IIIa, located at Siding Spring Observatory, Australia, responded to GRB 050922B (Swift trigger 156434), producing images beginning 5.6 s after the GCN notice time. An automated response took the first image at 15:05:06.6 UT, 186.3 s after the burst, under excellent conditions. We took 10 5-sec, and 140 20-sec exposures. These unfiltered images are calibrated relative to USNO A2.0 (R).
Comparison to the DSS (second epoch) reveals no new sources within the 3-sigma error circles for both the BAT and the XRT, for both single images and coadding into sets of 10. The field is not crowded but the gibbous moon was 57 degree away. Individual images have limiting magnitudes ranging from 15.4-16.5; we set the following specific limits.
```
start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd?
--------------------------------------------------------------------
15:05:06.6 15:07:30.6 144 17.3 186.3 Y
```
GCN notice #4019
D. Hullinger (UMD), L. Barbier (GSFC), S. Barthelmy (GSFC), J. Cummings (GSFC/NRC), E. Fenimore (LANL), F. Marshall (GSFC), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), A. Smale (NASA HQ), J. Tueller (GSFC) on behalf of the Swift-BAT team:
Using the data set from T-120 to T+450 sec from the recent telemetry downlink, we report further analysis of Swift-BAT GRB 050922B (trigger #156434) (Norris, et al., GCN 4008). The refined BAT ground position is (RA,Dec) = 5.789, -5.602 {00:23:09,-05:36:08} [deg; J2000] +-2.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 12%.
The light curve shows a broad peak from T+15 to T+65 and a second peak from T+80 to T+110. There is no extended emission T>120 sec. T90 (15-350 keV) is (80 +- 10) sec (estimated error including systematics).
The power law index of the time-averaged spectrum is 1.89 +- 0.23. The fluence in the 15-150 keV band is (1.8 +- 0.3) x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T0+98 sec in the 15-150 keV band is (1.1 +- 0.4) ph/cm2/sec. All the quoted errors are at the 90% confidence level.
GCN notice #4024
K. Torii (Osaka U.) reports:
The error region of Swift GRB 050922B (Norris et al. GCN 4008) was observed by the 14 inch Automated Response Telescope. BVRcIc imaging started at 2005 September 22, 15:07:42 UT (342 s after the trigger) and 60 s integration was repeated.
Due to low transparency and intermittent clouds, useful images were obtained after 15:16:47 UT. Preliminary analysis gives the following 3-sigma upper limits for an optical counterpart of the Swift XRT afterglow (GCN 4008).
```
------------------------------------------
StartUT	Filter	Limit	Exposure
------------------------------------------
15:17:55 Rc	15.5	60s	
17:02:44 Ic	17.1	40x60s	
------------------------------------------
```
GCN notice #4025
S. Guziy, M. Jelinek, J. Gorosabel, A.J. Castro-Tirado, A. de Ugarte Postigo (IAA-CSIC Granada, Spain), Ernesto Rodriguez Flores (IGA, La Habana, Cuba) and K. Vijanen (IAC-CSIC La Laguna, Spain)
report:
"We have acquired r' image of the GRB 050922B XRT error box (Norris et al. GCN 4008) with INT 2.5m telescope at Observatorio del Roque de los Muchachos on La Palma starting on September 23.1943 UT (i.e. 0.5678d after the GRB) with 600s exposure. No sources brighter than r'=22.5 (3-sigma) are detected within the 8" radius of the XRT error circle"
This message can be cited.
GCN notice #4028
M. De Pasquale (MSSL), J. Norris (GSFC), T. Kennedy (GSFC), K. Mason (PPARC), N. Gehrels (GSFC) on behalf of the Swift/UVOT team
The Swift/UVOT began observing the field of GRB050922B at 15:07:42 UT, 342 seconds after the BAT trigger (Hullinger et al., GCN 4019). There is no detection of an optical counterpart in the first 100 sec exposure finding chart down to a 3 sigma upper limit of V=18.7.
There is also no optical/UV counterpart detected in the summed images from all filters, down to the following 3 sigma magnitude upper limits:
```
  Filter  T_range(sec)  Exp(sec)  3sig UL

    V      342-5997      1158     20.1
    B      489-1720       258     20.2
    U      474-11434      720     20.5
    UVW1   580-7616       873     20.3
    UVM2   446-6904      1068     20.6
    UVW2   503-1826       258     20.1
```
Where T_range is the time post-trigger over which the summed images were accumulated and Exp is the total exposure time. The magnitudes upper limits are not corrected for extinction.
These magnitudes are based on preliminary zero- points, measured in orbit, and will require refinements with further calibrations.
GCN notice #4031
O. Godet, K.L. Page, J.P. Osborne (U. Leicester), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), K. Hurley (Berkeley), M. Chester (PSU) report on behalf of the Swift XRT team:
We have analyzed the Swift XRT data of the burst GRB 050922B from the first 3 orbits (~4 ks). The refined coordinates are:
```
RA(J2000) =  00h 23min 13.2s
Dec(J2000) = -05d 36' 16.4"
```
with an uncertainty of 7 arcseconds radius (90% containment). This position is consistent with that reported by Norris et al. (GCN 4008).
Initial data show two flares peaking at ~370 s and ~846 s after the trigger (T0), followed by a steep temporal decline decay (power law decline index ~ 2.75+/-0.14). Later data from the second and third orbits show a shallow decline with an temporal index ~ 0.95 +/- 0.41.
The X-ray spectrum after T0+5021 s is well fit by a power-law with Gamma = 1.9+0.3/-0.2 (90% confidence) and a Galactic absorbing column of 3.4e20 cm^-2.
If the light-curve is still unbroken at T0+24 h, the predicted unabsorbed 0.3-10 keV flux is ~1.6e-13 erg cm^-2 s^-1.
GCN notice #4033
J. Cummings (GSFC/NRC), L. Barbier (GSFC), S. Barthelmy (GSFC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), J. Tueller (GSFC) on behalf of the Swift-BAT team:
We report a correction to Hullinger et al. (GCN circ. 4019). There are two additional peaks in the interval T+260 to T+275 sec besides the broader, somewhat more intense peaks reported earlier. We had mistakenly stated that there was no emission after T+120. We have no mask-weighted data from T+300 to T+330 sec, but the raw rates show no peaks in this interval. There is no significant emission after T+330 sec; in particular, there does not seem to be any emission in the BAT energy range at the times of the Xray flares reported by Godet et al. (GCN circ. 4031).
The two later peaks are softer, shorter, and sharper. The total fluence from T+0 to T+300 sec is (2.6 +- 0.4) x 10^-6 ergs/cm^2 in the 15-150 keV band. The power-law photon index for the total burst is 2.1 +- 0.2. T90 is 250 +- 20 sec. Errors are 90% confidence including systematics.
GCN notice #4047
G. Kornienko (UAPhO), V.Rumyantsev (CrAO), A.Pozanenko (IKI) on behalf of larger GRB follow up collaboration report:
We have observed the error box of the Swift GRB050922B (Norris et al. GCN 4008) with 0.4m telescope of Ussuriysk Astrophysical Observatory (UAPhO) in R-band starting on Sep. 22 15:22 (UT). No new source was found in the GRB error box. Upper limit of a stacked image (10x60 s) calibrated against of USNO-A2.0 (R) is following:
```
Mid time,    Exposure, Filter, Limiting mag.
(UT)           (s)

Sep.22 15:37   10x60    R       16.0
```
The message may be cited.
1503.04246 from 13 Mar 15
photometric redshift of 4.5+-0.5
arXiv:1504.02482 SED fit of host: 5.0+0.2-0.8

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Jochen Greiner, last update: 07-Jul-2015 [Disclaimer]