Gamma-ray Burst 150323C

(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:     Mon 23 Mar 15 17:06:28 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     636005,   Seg_Num: 0
GRB_RA:          192.613d {+12h 50m 27s} (J2000),
                 192.785d {+12h 51m 08s} (current),
                 192.044d {+12h 48m 11s} (1950)
GRB_DEC:         +50.198d {+50d 11' 54"} (J2000),
                 +50.116d {+50d 06' 56"} (current),
                 +50.470d {+50d 28' 13"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       38996 [cnts]    Image_Peak=449 [image_cnts]
TRIGGER_DUR:     12.160 [sec] 
TRIGGER_INDEX:   478     E_range: 25-100 keV
BKG_INTEN:       192713 [cnts]
BKG_TIME:        61426.65 SOD {17:03:46.65} UT
BKG_DUR:         64 [sec]
GRB_DATE:        17104 TJD;    82 DOY;   15/03/23
GRB_TIME:        61521.49 SOD {17:05:21.49} UT
GRB_PHI:          16.21 [deg]
GRB_THETA:        45.52 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     10.72 [sigma]
IMAGE_SIGNIF:    7.46 [sigma]
MERIT_PARAMS:     +1  +0  +0  +4  +2  -2  +0  +0 +61  +0 
SUN_POSTN:         2.52d {+00h 10m 05s}   +1.09d {+01d 05' 34"}
SUN_DIST:        128.04 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
MOON_POSTN:       46.79d {+03h 07m 10s}  +14.20d {+14d 12' 12"}
MOON_DIST:       109.09 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:      123.33, 66.93 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      164.15, 49.51 [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 = 74.00,20.12 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(12.0<100sec) coincident with the FERMI_GBM event (trignum=448823112).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 23 Mar 15 17:05:35 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      44
TRIGGER_NUM:     448823112
GRB_RA:          191.767d {+12h 47m 04s} (J2000),
                 191.935d {+12h 47m 44s} (current),
                 191.211d {+12h 44m 51s} (1950)
GRB_DEC:         +56.833d {+56d 49' 60"} (J2000),
                 +56.750d {+56d 45' 01"} (current),
                 +57.106d {+57d 06' 22"} (1950)
GRB_ERROR:       22.22 [deg radius, statistical plus systematic]
GRB_INTEN:       55 [cnts/sec]
DATA_SIGNIF:     4.90 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        17104 TJD;    82 DOY;   15/03/23
GRB_TIME:        61509.64 SOD {17:05:09.64} UT
GRB_PHI:         242.00 [deg]
GRB_THETA:        55.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      1.22
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      97%  GRB
2nd_MOST_LIKELY:   1%  Generic SGR
DETECTORS:       0,0,0, 0,0,0, 0,1,1, 0,0,0, 0,0,
SUN_POSTN:         2.52d {+00h 10m 05s}   +1.09d {+01d 05' 33"}
SUN_DIST:        121.66 [deg]   Sun_angle= 11.4 [hr] (West of Sun)
MOON_POSTN:       46.78d {+03h 07m 08s}  +14.20d {+14d 12' 06"}
MOON_DIST:       103.36 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:      124.14, 60.28 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      156.70, 54.33 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2015/bn150323712/quicklook/glg_lc_medres34_bn150323712.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 57.72,-9.77 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 23 Mar 15 17:06:03 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      56
TRIGGER_NUM:     448823112
GRB_RA:          189.370d {+12h 37m 29s} (J2000),
                 189.545d {+12h 38m 11s} (current),
                 188.794d {+12h 35m 10s} (1950)
GRB_DEC:         +55.470d {+55d 28' 12"} (J2000),
                 +55.386d {+55d 23' 11"} (current),
                 +55.745d {+55d 44' 42"} (1950)
GRB_ERROR:       9.30 [deg radius, statistical only]
DATA_SIGNIF:     6.30 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        17104 TJD;    82 DOY;   15/03/23
GRB_TIME:        61509.64 SOD {17:05:09.64} UT
GRB_PHI:         240.00 [deg]
GRB_THETA:        54.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4153 (Gnd S/W Version number)
SUN_POSTN:         2.52d {+00h 10m 05s}   +1.09d {+01d 05' 34"}
SUN_DIST:        123.23 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:       46.79d {+03h 07m 09s}  +14.20d {+14d 12' 09"}
MOON_DIST:       103.68 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:      127.08, 61.55 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      156.51, 52.43 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2015/bn150323712/quicklook/glg_lc_medres34_bn150323712.gif
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 23 Mar 15 17:08:55 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     636005,   Seg_Num: 0
GRB_RA:          192.6177d {+12h 50m 28.24s} (J2000),
                 192.7904d {+12h 51m 09.70s} (current),
                 192.0489d {+12h 48m 11.73s} (1950)
GRB_DEC:         +50.1910d {+50d 11' 27.6"} (J2000),
                 +50.1083d {+50d 06' 29.9"} (current),
                 +50.4630d {+50d 27' 46.7"} (1950)
GRB_ERROR:       5.2 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.71e-09 [erg/cm2/sec]
GRB_SIGNIF:      8.60 [sigma]
IMG_START_DATE:  17104 TJD;    82 DOY;   15/03/23
IMG_START_TIME:  61691.34 SOD {17:08:11.34} UT,   169.8 [sec] since BAT Trigger Time
TAM[0-3]:        327.68 237.21 261.59 243.62
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:         2.52d {+00h 10m 06s}   +1.09d {+01d 05' 37"}
SUN_DIST:        128.05 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
MOON_POSTN:       46.82d {+03h 07m 16s}  +14.21d {+14d 12' 29"}
MOON_DIST:       109.08 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:      123.33, 66.94 [deg] galactic lon,lat of the burst
ECL_COORDS:      164.16, 49.50 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 0.47 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 23 Mar 15 17:09:20 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     636005,   Seg_Num: 0
GRB_RA:          192.613d {+12h 50m 27s} (J2000),
                 192.785d {+12h 51m 08s} (current),
                 192.044d {+12h 48m 11s} (1950)
GRB_DEC:         +50.198d {+50d 11' 54"} (J2000),
                 +50.116d {+50d 06' 56"} (current),
                 +50.470d {+50d 28' 13"} (1950)
GRB_DATE:        17104 TJD;    82 DOY;   15/03/23
GRB_TIME:        61521.49 SOD {17:05:21.49} UT
TRIGGER_INDEX:   478
GRB_PHI:          16.21 [deg]
GRB_THETA:        45.52 [deg]
DELTA_TIME:      -43.00 [sec]
TRIGGER_DUR:     12.160 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     10.72 [sigma]
IMAGE_SIGNIF:    7.46 [sigma]
LC_URL:          sw00636005000msb.lc
SUN_POSTN:         2.52d {+00h 10m 06s}   +1.09d {+01d 05' 37"}
SUN_DIST:        128.04 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
MOON_POSTN:       46.82d {+03h 07m 17s}  +14.21d {+14d 12' 32"}
MOON_DIST:       109.07 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:      123.33, 66.93 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      164.15, 49.51 [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 = 74.00,20.12 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 23 Mar 15 17:09:07 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     636005,   Seg_Num: 0
GRB_RA:          192.6177d {+12h 50m 28.2s} (J2000),
                 192.7904d {+12h 51m 09.7s} (current),
                 192.0489d {+12h 48m 11.7s} (1950)
GRB_DEC:         +50.1910d {+50d 11' 27.6"} (J2000),
                 +50.1083d {+50d 06' 29.9"} (current),
                 +50.4630d {+50d 27' 46.7"} (1950)
GRB_ERROR:       5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       74 [cnts]
IMG_START_DATE:  17104 TJD;    82 DOY;   15/03/23
IMG_START_TIME:  61691.34 SOD {17:08:11.34} UT,   169.8 [sec] since BAT Trigger Time
CENTROID_X:      248.01,  raw= 248  [pixels]
CENTROID_Y:      322.23,  raw= 322  [pixels]
ROLL:            12.82 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   57.59
GRB_POS_XRT_Z:   -135.04
IMAGE_URL:       sw00636005000msxps_rw.img
SUN_POSTN:         2.52d {+00h 10m 06s}   +1.09d {+01d 05' 37"}
SUN_DIST:        128.05 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
MOON_POSTN:       46.82d {+03h 07m 16s}  +14.21d {+14d 12' 31"}
MOON_DIST:       109.08 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:      123.33, 66.94 [deg] galactic lon,lat of the burst
ECL_COORDS:      164.16, 49.50 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 23 Mar 15 17:09:01 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     636005,   Seg_Num: 0
GRB_RA:          192.6177d {+12h 50m 28.2s} (J2000),
                 192.7904d {+12h 51m 09.7s} (current),
                 192.0489d {+12h 48m 11.7s} (1950)
GRB_DEC:         +50.1910d {+50d 11' 27.6"} (J2000),
                 +50.1083d {+50d 06' 29.9"} (current),
                 +50.4630d {+50d 27' 46.7"} (1950)
GRB_ERROR:       5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       74 [cnts]
IMG_START_DATE:  17104 TJD;    82 DOY;   15/03/23
IMG_START_TIME:  61691.34 SOD {17:08:11.34} UT,   169.8 [sec] since BAT Trigger Time
CENTROID_X:      248.01,  raw= 248  [pixels]
CENTROID_Y:      322.23,  raw= 322  [pixels]
ROLL:            12.82 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   57.59
GRB_POS_XRT_Z:   -135.04
IMAGE_URL:       sw00636005000msxps_rw.img
SUN_POSTN:         2.52d {+00h 10m 06s}   +1.09d {+01d 05' 37"}
SUN_DIST:        128.05 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
MOON_POSTN:       46.82d {+03h 07m 16s}  +14.21d {+14d 12' 30"}
MOON_DIST:       109.08 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:      123.33, 66.94 [deg] galactic lon,lat of the burst
ECL_COORDS:      164.16, 49.50 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 23 Mar 15 17:11:12 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     636005,   Seg_Num: 0
POINT_RA:        192.629d {+12h 50m 31s} (J2000)
POINT_DEC:       +50.151d {+50d 09' 02"} (J2000)
POINT_ROLL:      12.825d
IMG_START_DATE:  17104 TJD;    82 DOY;   15/03/23
IMG_START_TIME:  61700.10 SOD {17:08:20.10} UT,   178.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.514
N_STARS:         34
X_OFFSET:        680 [pixels]
Y_OFFSET:        272 [pixels]
X_MAX:           1639 [pixels]
Y_MAX:           1231 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00636005000msufc0178.fits
SUN_POSTN:         2.53d {+00h 10m 06s}   +1.09d {+01d 05' 39"}
SUN_DIST:        128.08 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
MOON_POSTN:       46.84d {+03h 07m 21s}  +14.21d {+14d 12' 46"}
MOON_DIST:       109.11 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:      123.31, 66.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      164.21, 49.47 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 23 Mar 15 17:11:36 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     636005,   Seg_Num: 0
POINT_RA:        192.629d {+12h 50m 31s} (J2000)
POINT_DEC:       +50.151d {+50d 09' 02"} (J2000)
POINT_ROLL:      12.825d
IMG_START_DATE:  17104 TJD;    82 DOY;   15/03/23
IMG_START_TIME:  61700.10 SOD {17:08:20.10} UT,   178.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.514
N_STARS:         34
X_OFFSET:        680 [pixels]
Y_OFFSET:        272 [pixels]
X_MAX:           1639 [pixels]
Y_MAX:           1231 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00636005000msufc0178.fits
SUN_POSTN:         2.53d {+00h 10m 06s}   +1.09d {+01d 05' 39"}
SUN_DIST:        128.08 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
MOON_POSTN:       46.84d {+03h 07m 22s}  +14.21d {+14d 12' 48"}
MOON_DIST:       109.11 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:      123.31, 66.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      164.21, 49.47 [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:     Mon 23 Mar 15 17:12:28 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     636005,   Seg_Num: 0
POINT_RA:        192.629d {+12h 50m 31s} (J2000)
POINT_DEC:       +50.151d {+50d 09' 02"} (J2000)
ROLL:            12.825d
IMG_START_DATE:  17104 TJD;    82 DOY;   15/03/23
IMG_START_TIME:  61700.10 SOD {17:08:20.10} UT,   178.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     448823313
X_OFFSET:        985 [pixels]
Y_OFFSET:        642 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1145
Y_GRB_POS:       802
BINNING_INDEX:   1
IM_URL:          sw00636005000msuni0192.fits
SUN_POSTN:         2.53d {+00h 10m 06s}   +1.09d {+01d 05' 40"}
SUN_DIST:        128.08 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
MOON_POSTN:       46.85d {+03h 07m 24s}  +14.22d {+14d 12' 55"}
MOON_DIST:       109.10 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:      123.31, 66.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      164.21, 49.47 [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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 23 Mar 15 17:12:46 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     636005,   Seg_Num: 0
POINT_RA:        192.629d {+12h 50m 31s} (J2000)
POINT_DEC:       +50.151d {+50d 09' 02"} (J2000)
ROLL:            12.825d
IMG_START_DATE:  17104 TJD;    82 DOY;   15/03/23
IMG_START_TIME:  61700.10 SOD {17:08:20.10} UT,   178.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     448823313
X_OFFSET:        985 [pixels]
Y_OFFSET:        642 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1145
Y_GRB_POS:       802
BINNING_INDEX:   1
IM_URL:          sw00636005000msuni0192.fits
SUN_POSTN:         2.53d {+00h 10m 06s}   +1.09d {+01d 05' 41"}
SUN_DIST:        128.08 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
MOON_POSTN:       46.85d {+03h 07m 25s}  +14.22d {+14d 12' 57"}
MOON_DIST:       109.10 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:      123.31, 66.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      164.21, 49.47 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN Circular #17621
A. Amaral-Rogers (U Leicester), W. H. Baumgartner (GSFC/UMBC), H. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (UCL-MSSL), K. L. Page (U Leicester), D. M. Palmer (LANL) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team:
At 17:05:21 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 150323C (trigger=636005). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 192.613, +50.198 which is
```
   RA(J2000) = 12h 50m 27s
   Dec(J2000) = +50d 11' 54"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of at least 40 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~5 sec after the trigger.
The XRT began observing the field at 17:08:11.3 UT, 169.8 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 192.6177, 50.1910 which is equivalent to:
```
   RA(J2000)  = +12h 50m 28.25s
   Dec(J2000) = +50d 11' 27.6" 
```
with an uncertainty of 5.2 arcseconds (radius, 90% containment). This location is 27 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy.
UVOT took a finding chart exposure of 150 seconds with the White filter starting 178 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.01.
Burst Advocate for this burst is A. Amaral-Rogers (aar14 AT 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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 23 Mar 15 17:17:52 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     636005,   Seg_Num: 0
POINT_RA:        192.628d {+12h 50m 31s} (J2000)
POINT_DEC:       +50.150d {+50d 09' 01"} (J2000)
POINT_ROLL:      12.822d
IMG_START_DATE:  17104 TJD;    82 DOY;   15/03/23
IMG_START_TIME:  61858.63 SOD {17:10:58.63} UT,   337.1 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.423
N_STARS:         19
X_OFFSET:        665 [pixels]
Y_OFFSET:        322 [pixels]
X_MAX:           1624 [pixels]
Y_MAX:           1281 [pixels]
DET_THRESH:      6
PHOTO_THRESH:    2
SL_URL:          sw00636005000msufc0337.fits
SUN_POSTN:         2.53d {+00h 10m 07s}   +1.10d {+01d 05' 46"}
SUN_DIST:        128.08 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
MOON_POSTN:       46.90d {+03h 07m 37s}  +14.23d {+14d 13' 33"}
MOON_DIST:       109.07 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:      123.31, 66.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      164.21, 49.47 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 23 Mar 15 17:18:09 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     636005,   Seg_Num: 0
POINT_RA:        192.628d {+12h 50m 31s} (J2000)
POINT_DEC:       +50.150d {+50d 09' 01"} (J2000)
POINT_ROLL:      12.822d
IMG_START_DATE:  17104 TJD;    82 DOY;   15/03/23
IMG_START_TIME:  61858.63 SOD {17:10:58.63} UT,   337.1 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.423
N_STARS:         19
X_OFFSET:        665 [pixels]
Y_OFFSET:        322 [pixels]
X_MAX:           1624 [pixels]
Y_MAX:           1281 [pixels]
DET_THRESH:      6
PHOTO_THRESH:    2
SL_URL:          sw00636005000msufc0337.fits
SUN_POSTN:         2.53d {+00h 10m 07s}   +1.10d {+01d 05' 46"}
SUN_DIST:        128.08 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
MOON_POSTN:       46.91d {+03h 07m 38s}  +14.23d {+14d 13' 35"}
MOON_DIST:       109.07 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:      123.31, 66.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      164.21, 49.47 [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_catalog_srclist.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 23 Mar 15 17:19:05 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     636005,   Seg_Num: 0
POINT_RA:        192.628d {+12h 50m 31s} (J2000)
POINT_DEC:       +50.150d {+50d 09' 01"} (J2000)
ROLL:            12.822d
IMG_START_DATE:  17104 TJD;    82 DOY;   15/03/23
IMG_START_TIME:  61858.63 SOD {17:10:58.63} UT,   337.1 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     448823471
X_OFFSET:        985 [pixels]
Y_OFFSET:        642 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1145
Y_GRB_POS:       802
BINNING_INDEX:   1
IM_URL:          sw00636005000msuni0351.fits
SUN_POSTN:         2.53d {+00h 10m 07s}   +1.10d {+01d 05' 47"}
SUN_DIST:        128.08 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
MOON_POSTN:       46.92d {+03h 07m 40s}  +14.23d {+14d 13' 42"}
MOON_DIST:       109.07 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:      123.31, 66.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      164.21, 49.47 [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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 23 Mar 15 17:19:24 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     636005,   Seg_Num: 0
POINT_RA:        192.628d {+12h 50m 31s} (J2000)
POINT_DEC:       +50.150d {+50d 09' 01"} (J2000)
ROLL:            12.822d
IMG_START_DATE:  17104 TJD;    82 DOY;   15/03/23
IMG_START_TIME:  61858.63 SOD {17:10:58.63} UT,   337.1 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     448823471
X_OFFSET:        985 [pixels]
Y_OFFSET:        642 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1145
Y_GRB_POS:       802
BINNING_INDEX:   1
IM_URL:          sw00636005000msuni0351.fits
SUN_POSTN:         2.53d {+00h 10m 07s}   +1.10d {+01d 05' 47"}
SUN_DIST:        128.08 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
MOON_POSTN:       46.92d {+03h 07m 41s}  +14.23d {+14d 13' 44"}
MOON_DIST:       109.06 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:      123.31, 66.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      164.21, 49.47 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_image.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 23 Mar 15 17:23:10 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     636005,   Seg_Num: 0
POINT_RA:        192.628d {+12h 50m 31s} (J2000)
POINT_DEC:       +50.150d {+50d 08' 60"} (J2000)
POINT_ROLL:      12.823d
IMG_START_DATE:  17104 TJD;    82 DOY;   15/03/23
IMG_START_TIME:  62391.91 SOD {17:19:51.91} UT,   870.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.503
N_STARS:         67
X_OFFSET:        425 [pixels]
Y_OFFSET:        82 [pixels]
X_MAX:           1864 [pixels]
Y_MAX:           1521 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00636005000msufc0870.fits
SUN_POSTN:         2.53d {+00h 10m 08s}   +1.10d {+01d 05' 51"}
SUN_DIST:        128.08 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
MOON_POSTN:       46.96d {+03h 07m 50s}  +14.24d {+14d 14' 11"}
MOON_DIST:       109.04 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:      123.31, 66.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      164.21, 49.47 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 23 Mar 15 17:23:28 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     636005,   Seg_Num: 0
POINT_RA:        192.628d {+12h 50m 31s} (J2000)
POINT_DEC:       +50.150d {+50d 08' 60"} (J2000)
POINT_ROLL:      12.823d
IMG_START_DATE:  17104 TJD;    82 DOY;   15/03/23
IMG_START_TIME:  62391.91 SOD {17:19:51.91} UT,   870.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.503
N_STARS:         67
X_OFFSET:        425 [pixels]
Y_OFFSET:        82 [pixels]
X_MAX:           1864 [pixels]
Y_MAX:           1521 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00636005000msufc0870.fits
SUN_POSTN:         2.53d {+00h 10m 08s}   +1.10d {+01d 05' 51"}
SUN_DIST:        128.08 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
MOON_POSTN:       46.96d {+03h 07m 50s}  +14.24d {+14d 14' 13"}
MOON_DIST:       109.04 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:      123.31, 66.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      164.21, 49.47 [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:     Mon 23 Mar 15 17:24:29 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     636005,   Seg_Num: 0
POINT_RA:        192.628d {+12h 50m 31s} (J2000)
POINT_DEC:       +50.150d {+50d 08' 60"} (J2000)
ROLL:            12.823d
IMG_START_DATE:  17104 TJD;    82 DOY;   15/03/23
IMG_START_TIME:  62391.91 SOD {17:19:51.91} UT,   870.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     448824005
X_OFFSET:        984 [pixels]
Y_OFFSET:        641 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1144
Y_GRB_POS:       801
BINNING_INDEX:   1
IM_URL:          sw00636005000msuni0884.fits
SUN_POSTN:         2.53d {+00h 10m 08s}   +1.10d {+01d 05' 52"}
SUN_DIST:        128.08 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
MOON_POSTN:       46.97d {+03h 07m 53s}  +14.24d {+14d 14' 20"}
MOON_DIST:       109.04 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:      123.31, 66.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      164.21, 49.47 [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:     Mon 23 Mar 15 17:24:41 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     636005,   Seg_Num: 0
POINT_RA:        192.628d {+12h 50m 31s} (J2000)
POINT_DEC:       +50.150d {+50d 08' 60"} (J2000)
ROLL:            12.823d
IMG_START_DATE:  17104 TJD;    82 DOY;   15/03/23
IMG_START_TIME:  62391.91 SOD {17:19:51.91} UT,   870.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     448824005
X_OFFSET:        984 [pixels]
Y_OFFSET:        641 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1144
Y_GRB_POS:       801
BINNING_INDEX:   1
IM_URL:          sw00636005000msuni0884.fits
SUN_POSTN:         2.53d {+00h 10m 08s}   +1.10d {+01d 05' 52"}
SUN_DIST:        128.08 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
MOON_POSTN:       46.97d {+03h 07m 53s}  +14.24d {+14d 14' 21"}
MOON_DIST:       109.04 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:      123.31, 66.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      164.21, 49.47 [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:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 23 Mar 15 17:24:07 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     636005,   Seg_Num: 0
GRB_RA:          192.6167d {+12h 50m 28.00s} (J2000),
                 192.7894d {+12h 51m 09.46s} (current),
                 192.0479d {+12h 48m 11.49s} (1950)
GRB_DEC:         +50.1918d {+50d 11' 30.4"} (J2000),
                 +50.1091d {+50d 06' 32.8"} (current),
                 +50.4638d {+50d 27' 49.6"} (1950)
GRB_ERROR:       2.2 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17104 TJD;    82 DOY;   15/03/23
IMG_START_TIME:  62012.00 SOD {17:13:32.00} UT,   490.5 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:         2.53d {+00h 10m 08s}   +1.10d {+01d 05' 52"}
SUN_DIST:        128.04 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
MOON_POSTN:       46.97d {+03h 07m 52s}  +14.24d {+14d 14' 17"}
MOON_DIST:       109.00 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:      123.33, 66.94 [deg] galactic lon,lat of the burst
ECL_COORDS:      164.16, 49.50 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        This is an Update Notice -- the RA,Dec values herein supersede the previous XRT_POS Notice.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        This position was enhanced using UVOT field astrometry.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.11% < P(seren) < 0.58%.

GCN Circular #17622
K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University
E. Gorbovskoy, V. Lipunov, M.Pruzhinskaya, V.Kornilov, D.Kuvshinov, N.Tyurina, N.Shatskiy, P.Balanutsa, D.Zimnukhov, A.Kuznetsov, V.V.Chazov, D.Denisenko, A.Sankovich Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University
V.Krushinsky, I.Zalozhnih, A. Popov Ural Federal University, Yekaterinburg, Kourovka
V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk
A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory
Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA)
D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Tunka was pointed to the GRB150323C 42 sec after notice time and 88 sec after trigger time at 2015-03-23 17:09:39 UT in two polarizations. On our first (20s exposure) set we haven`t found optical transient within SWIFT error-box (Amaral-Rogers et al. GCN17621). The 5-sigma upper limit has been about 17.6 mag
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Ural was pointed to the GRB150323C 35 after notice time and 79 sec after trigger time at 2015-03-23 17:09:31 UT in two polarizations. On our first (20s exposure) set we haven`t found optical transient within SWIFT error-box (ra=12 50 28 dec=+50 11 25 r=0.001400). The 5-sigma upper limit has been about 17.9 mag
The message may be cited.
GCN Circular #17624
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Using promptly downlinked XRT event data for GRB 150323C, we find an enhanced XRT position of the afterglow: RA, Dec: 192.6169, 50.1918 which is equivalent to:
```
   RA (J2000)  = 12 50 28.05
   Dec (J2000) = +50 11 30.4
```
with an uncertainty of 2.1 arcseconds (radius, 90% confidence). Analysis of the promptly available data is online at http://www.swift.ac.uk/sper/636005.
Position enhancement is is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular is an official product of the Swift-XRT team.
GCN Circular #17625
D. Xu (DARK/NBI), H.-B. Niu, J.-Z. Liu, G.-X. Pu, A. Esamdin, L. Ma (XAO) report:
We observed the field of GRB 150323C (Amaral-Rogers et al., GCN 17621) using the 1m telescope at Nanshan, Xinjiang, China. Observations were carried out in R-band, starting at 17:19:50 UT on 2015-03-23, i.e., 869 s after the burst.
A source, not present in SDSS and DSS, is well detected in individual images at coordinates
```
RA(J2000)  = 12:50:27.92
Dec(J2000) = +50:11:28.75
```
with an uncertainty of ~ 1 arcsec, being consistent with the enhanced Swift-XRT position (Evans, GCN 17624). We thus think it's the optical afterglow of the burst, and it has m(R) = 21.3 +/- 0.2 at a median time of 1344s post-burst, calibrated with the SDSS field.
GCN Circular #17627
Matthew Stanbro (UAH) reports on behalf of the Fermi GBM Team:
"At 17:05:09.64 UT on 23 March 2015, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 150323C (trigger 448823112 / 150323712) which was also detected by the Swift/BAT (Amaral-Rogers et al. 2015, GCN 17621) The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 58 degrees.
The GBM light curve consists of several episodes with a duration (T90) of about 43 s (50-300 keV). The time-averaged spectrum from T0-10.24 s to T0+30.72 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.15 +/- 0.16 and the cutoff energy, parameterized as Epeak, is 107 +/- 18 keV.
The event fluence (10-1000 keV) in this time interval is (2.50 +/- 0.19)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0-1.22 s in the 8-1000 keV band is 1.64 +/- 0.20 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #17629
D. Xu (DARK/NBI), X. Gao (Urumqi No.1 Senior High School, Xinjiang), and Z.-J. Xu (Nanjing Putian Telecommunications Co. Ltd., Jiangsu) report:
We observed the field of GRB 150323C (Amaral-Rogers et al., GCN 17621) using the 0.35m robotic Xingming telescope located at Nanshan, Xinjiang, China. Observations started at 17:08:06 UT on 2015-03-23, i.e., 165 s after the burst, and a series of 40s, 60s, and 90s unfiltered exposures were obtained.
No optical source is detected at the enhanced Swift-XRT position (Evans, GCN 17624), down to a limiting magnitude of ~19.2 mag since the starting of our observations.
GCN Circular #17630
V. D'Elia (ASDC), M. de Pasquale (INAF-IASFPA), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), K.L. Page (U. Leicester), C. Pagani (U. Leicester), A.P. Beardmore (U. Leicester), A. Maselli (INAF-IASFPA) and A. Amaral-Rogers report on behalf of the Swift-XRT team:
We have analysed 6.1 ks of XRT data for GRB 150323C (Amaral-Rogers et al. GCN Circ. 17621), from 160 s to 12.6 ks after the BAT trigger. The data comprise 312 s in Windowed Timing (WT) mode (the first 9 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The best available XRT position (using the promptly downlinked event data, the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue) is RA, Dec = 192.6169, 50.1918 which is equivalent to:
```
RA (J2000): 12 50 28.05
Dec(J2000): +50 11 30.4
```
with an uncertainty of 2.1 arcsec (radius, 90% confidence).
The late-time light curve (from T0+5.1 ks) can be modelled with a power-law decay with a decay index of alpha=1.0 (+/-0.5).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.34 (+/-0.05). The best-fitting absorption column is 1.55 (+0.13, -0.12) x 10^21 cm^-2, in excess of the Galactic value of 1.2 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 2.52 (+0.25, -0.23) and a best-fitting absorption column of 6.5 (+4.5, -3.9) x 10^20 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 2.7 x 10^-11 (3.5 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     6.5 (+4.5, -3.9) x 10^20 cm^-2
Galactic foreground: 1.2 x 10^20 cm^-2
Excess significance: 2.2 sigma
Photon index:	     2.52 (+0.25, -0.23)
```
If the light curve continues to decay with a power-law decay index of 1.0, the count rate at T+24 hours will be 3.7 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 9.8 x 10^-14 (1.3 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00636005.
This circular is an official product of the Swift-XRT team.
GCN Circular #17631
L. P. Xin, X. F. Wang, J. Y. Wei, Y. L. Qiu, J. S. Deng, J. Wang, X. H. Han and C. Wu on behalf of EAFON report:
We began to observe GRB 150323C (Amaral-Rogers et al., GCN 17621) with Xinglong 0.8-m TNT telescope at 2015-03-23, 17:07:27(UT), about 126 sec after the Swift trigger time.
The new source within XRT circle (Amaral-Rogers et al., GCN 17621 ) reported by Xu et al., ( GCN 17625 ) was clearly detected in our coadded images. Preliminary analysis shows that the brightness of this optical transient in R band is rising from 21.6 to 20.2 and then decaying, indicating that this source is the optical afterglow of the burst. All the magnitudes are calibrated by a nearby USNO B1.0 object ( RA: 16:50:26 DEC: 50:11:48, R2=16.47mag ).
The message may be cited.
GCN Circular #17632
Alan M. Watson (UNAM), Owen Littlejohns (ASU), Nat Butler (ASU), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Eleonora Troja (GSFC), Enrico Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
We observed the field of GRB 150323C (Amaral-Rogers, et al., GCN 17621) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astron=F3mico Nacional on Sierra San Pedro M=E1rtir from 2015/03 24.14 to 2015/03 24.27 UTC (10.20 to 13.42 hours after the BAT trigger), obtaining a total of 2.49 hours exposure in the r, i and z bands.
For a source within the Swift-XRT error circle (D'Elia, et al., GCN 17630), in comparison with the SDSS DR9, we obtain the following detections and upper limit (3-sigma):
```
  r     23.00 +/- 0.15
  i     22.63 +/- 0.11
  z     > 20.61
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. In comparison to an earlier epoch of observations (Xin, et al., GCN 17631) we find this magnitude to be consistent with a power-law decay with an approximate temporal decay index alpha =3D 0.5.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.
GCN Circular #17633
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 5836 s of XRT Photon Counting mode data and 7 UVOT images for GRB 150323C, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 192.61686, +50.19121 which is equivalent to:
```
RA (J2000): 12h 50m 28.05s
Dec (J2000): +50d 11' 28.4"
```
with an uncertainty of 1.6 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #17635
N. P. M. Kuin (UCL-MSSL) and A. Amaral-Rogers (U Leicester) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 150323C 179 s after the BAT trigger (Amaral-Rogers et al., GCN Circ. 17621). No optical afterglow consistent with the optical position (Xu et al. GCN Circ. 17625) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC           179          328          147         >21.5
u_FC               337          587          246         >20.7
white              179        11759         1513         >22.4
v                  669        12698          555         >21.0
b                  594         7661          444         >21.1
u                  337         7541          717         >21.0
w1                 718         7337          432         >21.2
m2                5494         7131          393         >20.6
w2                5084        12665         1279         >22.1
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #17636
Alan M. Watson (UNAM), Owen Littlejohns (ASU), Nat Butler (ASU), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Eleonora Troja (GSFC), Enrico Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
In Watson et al. (GCN Circular 17632), we compared our RATIR observations of GRB 150323C to earlier observations to derive an approximate temporal power-law index of 0.5. We unfortunately gave an incorrect reference to the earlier observations; the correct reference is Xu et al. (GCN Circular 17625).
We apologise for any confusion.
GCN Circular #17637
D. M. Palmer (LANL), Amaral-Rogers (U Leicester), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), T. Sakamoto (AGU), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-274 to T+800 sec from the recent telemetry downlink, we report further analysis of BAT GRB 150323C (trigger #636005) (Amaral-Rogers, et al., GCN Circ. 17621). The BAT ground-calculated position is RA, Dec = 192.625, 50.165 deg which is
```
  RA(J2000)  =  12h 50m 30.1s
  Dec(J2000) = +50d 09' 55.3"
```
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 26%.
The mask-weighted light curve shows several weak overlapping pulses. The main burst structure starts at ~ T-20 s and ends at ~T+20 s, followed by another weaker pulse lasting till ~ T+160 s. T90 (15-350 keV) is 159.4 +- 54.0 sec (estimated error including systematics).
The time-averaged spectrum from T-22.9 to T+166.3 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.09 +- 0.32. The fluence in the 15-150 keV band is 1.3 +- 0.3 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+5.98 sec in the 15-150 keV band is 1.1 +- 0.3 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/636005/BA/
GCN Circular #17639
E. Mazaeva (IKI), A. Volnova (IKI), E. Klunko (ISTP), I. Korobtsev (ISTP), M. Eselevich (ISTP), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of the GRB 150323C (Amaral-Rogers et al., GCN 17621) with AZT-33IK telescope of Sayan observatory (Mondy) starting on Mar., 23 (UT) 11:42:02. We obtained several images in R-filter of 120 s exposure. Within enhanced Swift-XRT error circle (Osborne et al., GCN 17633) we clearly detect optical afterglow (Xu et al. GCN 17625, Xin et al. GCN 17631; Watson et al. GCN 17632) in a combined image. Preliminary photometry of the afterglow is following
```
Date       UT start   t-T0     Filter   Exp.    OT    Err.
                       (mid, days)       (s)

2015-03-24 15:14:09   0.95405  R        44*120  22.4 0.3
```
Photometry is based on SDSS DR9 stars:
```
SDSS9_id            R(Lupton)
J125023.08+501048.2 16.84
J125032.04+501021.5 18.37
J125016.28+501035.8 18.22
```
GCN Circular #17644
J. Kelemen (kelemen at konkoly.hu) on behalf of the GRB OT observing program at the Konkoly Observatory.
Starting on the night 23/03/2015 we observed the field GRB 150323C (A. Amaral-Rogers et al. GCN 17621 ). On the position reported by D. Xu et al. (GCN 17625) according our coadded R images we confirmed the presence of a marginal optical source in R band.
```
Position from D. Xu                    our work
---------------------------------------------------------------

RA(J2000)  = 12:50:27.92            RA: 12:50:28.02
Dec(J2000) = +50:11:28.75          DEC: 50:11:28.3
```
Photometric results: (Based on nearby USNO-B1.0 stars)
```
time from GRB.    exp    filter     Mag.      
------------------------------------------------
 10653 s.       1800 s     R       21.7 +/-0.18
------------------------------------------------ 
```
GCN Circular #17646
T.Fujiwara, Y. Saito, T. Yoshii, Y. Tachibana, H. Ohuchi, Y. Yano, S.Kurita, Y. Ono, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration:
We observed the field of GRB 150323C (Amaral-Rogers et al. GCN Circular #17621) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan.
The observation started at 2015-03-23 17:06:46 UT (85 sec after the burst). We detected the previously reported optical afterglow (Xu et al. GCN Circular #17625) in the Rc band.
The measured magnitudes are listed below.
```
T0+[sec]  MID-UT  T-EXP[sec]    g'                Rc             Ic
----------------------------------------------------------------------
85   17:09:24  270     > 19.9  > 19.6  > 18.5
1069   17:34:06  1200    > 20.9  20.3 $B!^(B 0.5  > 19.5
6681   19:18:53  2400    > 20.4  > 20.4  > 19.4
----------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
```
We used GSC2.3 catalog for flux calibration.
GCN Circular #17648
S. Honda. J. Takahashi, Y. Takagi, K. Morihana, Y. Itoh (Univ. of Hyogo), and Y. Saito (Tokyo Tech) report on behalf of Nayuta team and OISTER collaboration:
We observed the field of GRB 150323C (Amaral-Rogers et al., GCN 17621) with Nishiharima Infrared Camera (NIC) attached to the Nayuta 2-m telescope at the Nishi-Harima Astronomical Observatory.
The observations were started at 17:30 UT on 2015-03-23. We detected the near-infrared afterglow in J, H and Ks bands.
Photometric results of our observations are shown below. We used 2MASS 12502614+5011480, 12502605+5011289, 12503202+5010217, and 12503649+5012012 as reference stars for photometry.
```
# MID-UT  Tmid-T0 T-EXP  J_mag           H_mag               Ks_mag
-----------------------------------------------------------------------------
17:33:16    28   1200   18.22 +/- 0.10   17.25 +/- 0.10   16.44 +/- 0.13
17:59:27    54   1200   18.68 +/- 0.11   17.59 +/- 0.11   16.94 +/- 0.14
18:25:32    80   1200   19.40 +/- 0.20   17.77 +/- 0.13   17.23 +/- 0.14
-----------------------------------------------------------------------------
Tmid-T0: Elapsed time after the burst (minutes)
T-EXP: Total Exposure time (seconds)
```
GCN Circular #17655
Daniele Malesani (DARK/NBI), Dong Xu (DARK/NBI), Pall Jakobsson (Univ. Iceland) and Jussi Harmanen (NOT and Univ. Helsinki) report on behalf of a larger collaboration:
We observed the field of GRB 150323C (Amaral-Rogers et al., GCN 17621; Stanbro, GCN 17627) using the Nordic Optical Telescope (NOT) located in La Palma. The mean time of the observation was March 28.21 UT, that is 4.49 days after the GRB. A 20 min exposure was collected using the SDSS r filter.
Close to the position of the optical afterglow (Xu et al., GCN 17625; Watson et al., GCN 17632), we detect an object with r = 23.6 +- 0.2 AB (calibrated against nearby SDSS stars). This source is also marginally detected in the archival SDSS images with a comparable (though uncertain) brightness, and therefore an underlying galaxy must be contributing a significant fraction of the light.
We note a small, but significant offset between the afterglow and the galaxy positions. By registering astrometrically the afterglow image by Xu et al. (GCN 17625) with the new NOT data, we find an offset of approximately 0.65". Such an offset is not unprecedented, so that the SDSS/NOT object is still a viable host galaxy candidate for GRB 150323C.
GCN Circular #17669
E. Mazaeva (IKI), S. Schmalz (AIP), N. Tungalag (Research Center of Astronomy and Geophysics MAS), A. Volnova (IKI), I.Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of the GRB 150323C (Amaral-Rogers et al., GCN 17621) with ORI-40 telescope of Khureltogot observatory starting on Mar., 23 (UT) 17:20:51, i.e. ~15 minutes after burst trigger. We obtained 180 unfiltered images of 60 s exposure. Within enhanced Swift-XRT error circle (Osborne et al., GCN 17633) we detect optical afterglow (Xu et al. GCN 17625, Xin et al. GCN 17631; Watson et al. GCN 17632). Preliminary photometry of the afterglow in combined images is following
```
Date        UT start  t-T0                  Filter      Exp.   OT  OT_err
                       (mid, days)                              (s)

2015-01-23  17:20:51  0.01449   none    10*60  21.1 0.3
2015-01-23  17:31:40  0.02199   none    10*60  20.5 0.25
2015-01-23  17:42:28  0.02950   none    10*60  20.8 0.25
2015-01-23  17:53:17  0.03700   none    10*60  20.2 0.2
2015-01-23  18:04:04  0.04451   none    10*60  20.0 0.2
2015-01-23  18:14:54  0.06199   none    35*60  21.3 0.3
2015-01-23  18:54:26  0.09409   none    39*60  21.0 0.3
2015-01-23  19:57:04  0.13649   none    40*60  21.5 0.4
```
Photometry is based on SDSS DR9 stars:
```
SDSS9_id                        R(Lupton)
J125026.13+501147.9  16.16
J125023.08+501048.2  16.84
```
Our photometry confirms non-monotonic behaiviour of a lighr curve of the afterglow mentioned by Xin et al. (GCN 17631). The light curve of GRB 150323C afterglow can be found in http://grb.rssi.ru/GRB150323C/GRB150323C_ORI40_lc.png
GCN Circular #17670
E. Mazaeva (IKI), A. Volnova (IKI), E. Klunko (ISTP), I. Korobtsev (ISTP), M. Eselevich (ISTP), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We additionally observed the field of the GRB 150323C (Amaral-Rogers et al., GCN 17621) with AZT-33IK telescope of Sayan observatory (Mondy) on Mar., 27 and Mar. 30 under good weather conditions and mean FWHV of 1.8 arcsec. We obtained several images in R-filter of 120 s exposure. In both epochs we detect a source in coordinates (J2000) 12 50 27.90 +50 11 29.0 (+/- 0.45" ) which is within afterglow coordinates (Xu et al., GCN 17625) and within the enhanced Swift-XRT position (Osborne et al., GCN 17633). Our object is apparently the same object suggested as a possible host galaxy (Malesani et al., GCN 17655). Preliminary photometry of the source is following
```
Date       UT start           t-T0        Filter   Exp.       OT    Err.
                                       (mid, days)       (s)

2015-03-27 18:22:30   4.11333  R        85*120  22.7 0.25
2015-03-30 14:09:29   7.02068  R      194*120  22.3 0.15
```
Photometry is based on SDSS DR9 stars:
```
SDSS9_id            R(Lupton)
J125023.08+501048.2 16.84
J125032.04+501021.5 18.37
```
Also we note that our photometry reported early (Mazaeva et al., GCN 17639) may by significantly be significantly influenced by the possible host galaxy.
GCN Circular #17671
V. Rumyantsev (CrAO), K. Antoniuk (CrAO), E. Mazaeva (IKI), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of the GRB 150323C (Amaral-Rogers et al., GCN 17621) with AZT-11 telescope of CrAO observatory starting on Mar. 23 (UT) 20:09:58. We obtained ages in R-filter of 180 s exposure under non-optimal weather conditions and mean FWHM of about 4.7 arcsec. In the enhanced XRT position (Osborne et al., GCN 17633) we do not detect any object. In particular we do no detect optical afterglow (Xu et al. GCN 17625, Xin et al. GCN 17631; Watson et al. GCN 17632). An upper limit is following
```
Date              UT start,    t-t0          Filter   Exp.     OT   UL (3 
sigma)
                                        (mid, days)         (s)

2015-03-23 20:09:58   0.14949  R        20*180  n/d  21.0
```
The photometry is based on nearby USNO-B1.0 stars.

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Jochen Greiner, last update: 04-Apr-2015 [Disclaimer]