Gamma-ray Burst 070318

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 18 Mar 07 07:29:08 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     271019,   Seg_Num: 0
GRB_RA:           48.540d {+03h 14m 10s} (J2000),
                  48.605d {+03h 14m 25s} (current),
                  48.094d {+03h 12m 23s} (1950)
GRB_DEC:         -42.962d {-42d 57' 42"} (J2000),
                 -42.935d {-42d 56' 06"} (current),
                 -43.147d {-43d 08' 48"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       2934 [cnts]    Image_Peak=201 [image_cnts]
TRIGGER_DUR:     0.512 [sec] 
TRIGGER_INDEX:   124     E_range: 25-100 keV
BKG_INTEN:       32572 [cnts]
BKG_TIME:        26926.16 SOD {07:28:46.16} UT
BKG_DUR:         8 [sec]
GRB_DATE:        14177 TJD;    77 DOY;   07/03/18
GRB_TIME:        26936.08 SOD {07:28:56.08} UT
GRB_PHI:         -57.23 [deg]
GRB_THETA:        21.51 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     17.94 [sigma]
IMAGE_SIGNIF:    10.03 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2 +12  +0  +0 -47  +1 
SUN_POSTN:       357.54d {+23h 50m 10s}   -1.07d {-01d 03' 53"}
SUN_DIST:         61.79 [deg]   Sun_angle= -3.4 [hr] (East of Sun)
MOON_POSTN:      347.31d {+23h 09m 13s}   -5.41d {-05d 24' 51"}
MOON_DIST:        65.53 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      251.10,-57.12 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       25.59,-57.50 [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 = 81.52,-20.02 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 18 Mar 07 07:30:35 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     271019,   Seg_Num: 0
GRB_RA:           48.4856d {+03h 13m 56.5s} (J2000),
                  48.5500d {+03h 14m 11.9s} (current),
                  48.0391d {+03h 12m 09.3s} (1950)
GRB_DEC:         -42.9468d {-42d 56' 48.4"} (J2000),
                 -42.9202d {-42d 55' 12.7"} (current),
                 -43.1321d {-43d 07' 55.7"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       91 [cnts]
IMG_START_DATE:  14177 TJD;    77 DOY;   07/03/18
IMG_START_TIME:  26999.66 SOD {07:29:59.66} UT,   63.6 [sec] since BAT Trigger Time
CENTROID_X:      209.14,  raw= 209  [pixels]
CENTROID_Y:      302.22,  raw= 302  [pixels]
ROLL:            298.10 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   9.96
GRB_POS_XRT_Z:   -219.60
IMAGE_URL:       sw00271019000msxps_rw.img
SUN_POSTN:       357.54d {+23h 50m 10s}   -1.06d {-01d 03' 52"}
SUN_DIST:         61.75 [deg]   Sun_angle= -3.4 [hr] (East of Sun)
MOON_POSTN:      347.32d {+23h 09m 16s}   -5.41d {-05d 24' 25"}
MOON_DIST:        65.48 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      251.09,-57.16 [deg] galactic lon,lat of the burst
ECL_COORDS:       25.54,-57.47 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 18 Mar 07 07:30:28 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     271019,   Seg_Num: 0
GRB_RA:           48.4856d {+03h 13m 56.5s} (J2000),
                  48.5500d {+03h 14m 11.9s} (current),
                  48.0391d {+03h 12m 09.3s} (1950)
GRB_DEC:         -42.9468d {-42d 56' 48.4"} (J2000),
                 -42.9202d {-42d 55' 12.7"} (current),
                 -43.1321d {-43d 07' 55.7"} (1950)
GRB_ERROR:       4.7 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       2.61e-09 [erg/cm2/sec]
GRB_SIGNIF:      9.53 [sigma]
IMG_START_DATE:  14177 TJD;    77 DOY;   07/03/18
IMG_START_TIME:  26999.66 SOD {07:29:59.66} UT,   63.6 [sec] since BAT Trigger Time
TAM[0-3]:        327.66 237.17 261.31 243.42
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       357.54d {+23h 50m 10s}   -1.06d {-01d 03' 52"}
SUN_DIST:         61.75 [deg]   Sun_angle= -3.4 [hr] (East of Sun)
MOON_POSTN:      347.32d {+23h 09m 16s}   -5.41d {-05d 24' 27"}
MOON_DIST:        65.48 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      251.09,-57.16 [deg] galactic lon,lat of the burst
ECL_COORDS:       25.54,-57.47 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 18 Mar 07 07:30:29 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     271019,   Seg_Num: 0
GRB_RA:           48.4856d {+03h 13m 56.5s} (J2000),
                  48.5500d {+03h 14m 11.9s} (current),
                  48.0391d {+03h 12m 09.3s} (1950)
GRB_DEC:         -42.9468d {-42d 56' 48.4"} (J2000),
                 -42.9202d {-42d 55' 12.7"} (current),
                 -43.1321d {-43d 07' 55.7"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       91 [cnts]
IMG_START_DATE:  14177 TJD;    77 DOY;   07/03/18
IMG_START_TIME:  26999.66 SOD {07:29:59.66} UT,   63.6 [sec] since BAT Trigger Time
CENTROID_X:      209.14,  raw= 209  [pixels]
CENTROID_Y:      302.22,  raw= 302  [pixels]
ROLL:            298.10 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   9.96
GRB_POS_XRT_Z:   -219.60
IMAGE_URL:       sw00271019000msxps_rw.img
SUN_POSTN:       357.54d {+23h 50m 10s}   -1.06d {-01d 03' 52"}
SUN_DIST:         61.75 [deg]   Sun_angle= -3.4 [hr] (East of Sun)
MOON_POSTN:      347.32d {+23h 09m 16s}   -5.41d {-05d 24' 27"}
MOON_DIST:        65.48 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      251.09,-57.16 [deg] galactic lon,lat of the burst
ECL_COORDS:       25.54,-57.47 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 18 Mar 07 07:32:05 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     271019,   Seg_Num: 0
POINT_RA:         48.560d {+03h 14m 14s} (J2000)
POINT_DEC:       -42.973d {-42d 58' 20"} (J2000)
POINT_ROLL:      298.098d
IMG_START_DATE:  14177 TJD;    77 DOY;   07/03/18
IMG_START_TIME:  27010.16 SOD {07:30:10.16} UT,   74.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.635
N_STARS:         17
X_OFFSET:        870 [pixels]
Y_OFFSET:        321 [pixels]
X_MAX:           1829 [pixels]
Y_MAX:           1280 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00271019000msufc0074.fits
SUN_POSTN:       357.54d {+23h 50m 10s}   -1.06d {-01d 03' 50"}
SUN_DIST:         61.81 [deg]   Sun_angle= -3.4 [hr] (East of Sun)
MOON_POSTN:      347.33d {+23h 09m 20s}   -5.40d {-05d 23' 59"}
MOON_DIST:        65.53 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      251.11,-57.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       25.61,-57.52 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 18 Mar 07 07:32:32 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     271019,   Seg_Num: 0
POINT_RA:         48.560d {+03h 14m 14s} (J2000)
POINT_DEC:       -42.973d {-42d 58' 20"} (J2000)
POINT_ROLL:      298.098d
IMG_START_DATE:  14177 TJD;    77 DOY;   07/03/18
IMG_START_TIME:  27010.16 SOD {07:30:10.16} UT,   74.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.635
N_STARS:         17
X_OFFSET:        870 [pixels]
Y_OFFSET:        321 [pixels]
X_MAX:           1829 [pixels]
Y_MAX:           1280 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00271019000msufc0074.fits
SUN_POSTN:       357.54d {+23h 50m 11s}   -1.06d {-01d 03' 50"}
SUN_DIST:         61.81 [deg]   Sun_angle= -3.4 [hr] (East of Sun)
MOON_POSTN:      347.34d {+23h 09m 21s}   -5.40d {-05d 23' 51"}
MOON_DIST:        65.53 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      251.11,-57.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       25.61,-57.52 [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:     Sun 18 Mar 07 07:33:20 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     271019,   Seg_Num: 0
POINT_RA:         48.560d {+03h 14m 14s} (J2000)
POINT_DEC:       -42.973d {-42d 58' 20"} (J2000)
ROLL:            298.098d
IMG_START_DATE:  14177 TJD;    77 DOY;   07/03/18
IMG_START_TIME:  27010.16 SOD {07:30:10.16} UT,   74.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     195895811
X_OFFSET:        1190 [pixels]
Y_OFFSET:        641 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1350
Y_GRB_POS:       801
BINNING_INDEX:   1
IM_URL:          sw00271019000msuni0074.fits
SUN_POSTN:       357.54d {+23h 50m 11s}   -1.06d {-01d 03' 49"}
SUN_DIST:         61.81 [deg]   Sun_angle= -3.4 [hr] (East of Sun)
MOON_POSTN:      347.34d {+23h 09m 23s}   -5.39d {-05d 23' 37"}
MOON_DIST:        65.53 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      251.11,-57.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       25.61,-57.52 [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:     Sun 18 Mar 07 07:33:37 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     271019,   Seg_Num: 0
POINT_RA:         48.560d {+03h 14m 14s} (J2000)
POINT_DEC:       -42.973d {-42d 58' 20"} (J2000)
ROLL:            298.098d
IMG_START_DATE:  14177 TJD;    77 DOY;   07/03/18
IMG_START_TIME:  27010.16 SOD {07:30:10.16} UT,   74.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     195895811
X_OFFSET:        1190 [pixels]
Y_OFFSET:        641 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1350
Y_GRB_POS:       801
BINNING_INDEX:   1
IM_URL:          sw00271019000msuni0074.fits
SUN_POSTN:       357.54d {+23h 50m 11s}   -1.06d {-01d 03' 49"}
SUN_DIST:         61.81 [deg]   Sun_angle= -3.4 [hr] (East of Sun)
MOON_POSTN:      347.35d {+23h 09m 23s}   -5.39d {-05d 23' 32"}
MOON_DIST:        65.53 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      251.11,-57.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       25.61,-57.52 [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:     Sun 18 Mar 07 07:33:32 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     271019,   Seg_Num: 0
GRB_RA:           48.540d {+03h 14m 10s} (J2000),
                  48.605d {+03h 14m 25s} (current),
                  48.094d {+03h 12m 23s} (1950)
GRB_DEC:         -42.962d {-42d 57' 42"} (J2000),
                 -42.935d {-42d 56' 06"} (current),
                 -43.147d {-43d 08' 48"} (1950)
GRB_DATE:        14177 TJD;    77 DOY;   07/03/18
GRB_TIME:        26936.08 SOD {07:28:56.08} UT
TRIGGER_INDEX:   124
GRB_PHI:         -57.23 [deg]
GRB_THETA:        21.51 [deg]
DELTA_TIME:      -31.00 [sec]
TRIGGER_DUR:     0.512 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     17.94 [sigma]
IMAGE_SIGNIF:    10.03 [sigma]
LC_URL:          sw00271019000msb.lc
SUN_POSTN:       357.54d {+23h 50m 11s}   -1.06d {-01d 03' 49"}
SUN_DIST:         61.79 [deg]   Sun_angle= -3.4 [hr] (East of Sun)
MOON_POSTN:      347.35d {+23h 09m 23s}   -5.39d {-05d 23' 33"}
MOON_DIST:        65.51 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      251.10,-57.12 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       25.59,-57.50 [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 = 81.52,-20.02 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 18 Mar 07 07:39:30 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     271019,   Seg_Num: 0
POINT_RA:         48.563d {+03h 14m 15s} (J2000)
POINT_DEC:       -42.975d {-42d 58' 28"} (J2000)
POINT_ROLL:      298.098d
IMG_START_DATE:  14177 TJD;    77 DOY;   07/03/18
IMG_START_TIME:  27115.67 SOD {07:31:55.67} UT,   179.6 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.315
N_STARS:         15
X_OFFSET:        870 [pixels]
Y_OFFSET:        321 [pixels]
X_MAX:           1829 [pixels]
Y_MAX:           1280 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00271019000msufc0179.fits
SUN_POSTN:       357.55d {+23h 50m 12s}   -1.06d {-01d 03' 43"}
SUN_DIST:         61.81 [deg]   Sun_angle= -3.4 [hr] (East of Sun)
MOON_POSTN:      347.40d {+23h 09m 36s}   -5.36d {-05d 21' 48"}
MOON_DIST:        65.51 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      251.11,-57.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       25.61,-57.52 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 18 Mar 07 07:39:56 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     271019,   Seg_Num: 0
POINT_RA:         48.563d {+03h 14m 15s} (J2000)
POINT_DEC:       -42.975d {-42d 58' 28"} (J2000)
POINT_ROLL:      298.098d
IMG_START_DATE:  14177 TJD;    77 DOY;   07/03/18
IMG_START_TIME:  27115.67 SOD {07:31:55.67} UT,   179.6 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.315
N_STARS:         15
X_OFFSET:        870 [pixels]
Y_OFFSET:        321 [pixels]
X_MAX:           1829 [pixels]
Y_MAX:           1280 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00271019000msufc0179.fits
SUN_POSTN:       357.55d {+23h 50m 12s}   -1.06d {-01d 03' 43"}
SUN_DIST:         61.81 [deg]   Sun_angle= -3.4 [hr] (East of Sun)
MOON_POSTN:      347.41d {+23h 09m 37s}   -5.36d {-05d 21' 41"}
MOON_DIST:        65.51 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      251.11,-57.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       25.61,-57.52 [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 18 Mar 07 07:40:40 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     271019,   Seg_Num: 0
POINT_RA:         48.563d {+03h 14m 15s} (J2000)
POINT_DEC:       -42.975d {-42d 58' 28"} (J2000)
ROLL:            298.098d
IMG_START_DATE:  14177 TJD;    77 DOY;   07/03/18
IMG_START_TIME:  27115.67 SOD {07:31:55.67} UT,   179.6 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     195895917
X_OFFSET:        1190 [pixels]
Y_OFFSET:        641 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1350
Y_GRB_POS:       801
BINNING_INDEX:   1
IM_URL:          sw00271019000msuni0179.fits
SUN_POSTN:       357.55d {+23h 50m 12s}   -1.06d {-01d 03' 42"}
SUN_DIST:         61.81 [deg]   Sun_angle= -3.4 [hr] (East of Sun)
MOON_POSTN:      347.41d {+23h 09m 39s}   -5.36d {-05d 21' 28"}
MOON_DIST:        65.51 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      251.11,-57.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       25.61,-57.52 [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:     Sun 18 Mar 07 07:41:02 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     271019,   Seg_Num: 0
POINT_RA:         48.563d {+03h 14m 15s} (J2000)
POINT_DEC:       -42.975d {-42d 58' 28"} (J2000)
ROLL:            298.098d
IMG_START_DATE:  14177 TJD;    77 DOY;   07/03/18
IMG_START_TIME:  27115.67 SOD {07:31:55.67} UT,   179.6 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     195895917
X_OFFSET:        1190 [pixels]
Y_OFFSET:        641 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1350
Y_GRB_POS:       801
BINNING_INDEX:   1
IM_URL:          sw00271019000msuni0179.fits
SUN_POSTN:       357.55d {+23h 50m 12s}   -1.06d {-01d 03' 42"}
SUN_DIST:         61.81 [deg]   Sun_angle= -3.4 [hr] (East of Sun)
MOON_POSTN:      347.42d {+23h 09m 40s}   -5.36d {-05d 21' 21"}
MOON_DIST:        65.51 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      251.11,-57.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       25.61,-57.52 [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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 18 Mar 07 07:47:21 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     271019,   Seg_Num: 0
POINT_RA:         48.564d {+03h 14m 15s} (J2000)
POINT_DEC:       -42.975d {-42d 58' 29"} (J2000)
ROLL:            298.098d
IMG_START_DATE:  14177 TJD;    77 DOY;   07/03/18
IMG_START_TIME:  27800.09 SOD {07:43:20.09} UT,   864.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     195896601
X_OFFSET:        1189 [pixels]
Y_OFFSET:        640 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1349
Y_GRB_POS:       800
BINNING_INDEX:   1
IM_URL:          sw00271019000msuni0864.fits
SUN_POSTN:       357.55d {+23h 50m 13s}   -1.06d {-01d 03' 35"}
SUN_DIST:         61.81 [deg]   Sun_angle= -3.4 [hr] (East of Sun)
MOON_POSTN:      347.47d {+23h 09m 54s}   -5.33d {-05d 19' 30"}
MOON_DIST:        65.49 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      251.11,-57.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       25.61,-57.52 [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 18 Mar 07 07:47:38 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     271019,   Seg_Num: 0
POINT_RA:         48.564d {+03h 14m 15s} (J2000)
POINT_DEC:       -42.975d {-42d 58' 29"} (J2000)
ROLL:            298.098d
IMG_START_DATE:  14177 TJD;    77 DOY;   07/03/18
IMG_START_TIME:  27800.09 SOD {07:43:20.09} UT,   864.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     195896601
X_OFFSET:        1189 [pixels]
Y_OFFSET:        640 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1349
Y_GRB_POS:       800
BINNING_INDEX:   1
IM_URL:          sw00271019000msuni0864.fits
SUN_POSTN:       357.55d {+23h 50m 13s}   -1.06d {-01d 03' 35"}
SUN_DIST:         61.81 [deg]   Sun_angle= -3.4 [hr] (East of Sun)
MOON_POSTN:      347.48d {+23h 09m 54s}   -5.32d {-05d 19' 25"}
MOON_DIST:        65.49 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      251.11,-57.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       25.61,-57.52 [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 Circular #6210
J. R. Cummings (NASA/UMBC), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), G. Cusumano (INAF-IASFPA), N. Gehrels (NASA/GSFC), C. Gronwall (PSU), V. La Parola (INAF-IASFPA), T. Mineo (INAF-IASFPA) and D. M. Palmer (LANL) report on behalf of the Swift Team:
At 07:28:56 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 070318 (trigger=271019). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 48.540, -42.962 which is
```
   RA(J2000)  =  03h 14m 10s
   Dec(J2000) = -42d 57' 42"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single FRED-like peak with a duration of about 70 sec. The peak count rate was ~4000 counts/sec (15-350 keV), at ~2 sec after the trigger.
The XRT began observing the field at 07:29:59 UT, 64 seconds after the BAT trigger. XRT found a bright, fading, uncatalogued X-ray source located at RA, Dec 48.4856, -42.9468 which is
```
   RA(J2000)  =  03h 13m 56.5s
   Dec(J2000) = -42d 56' 48.4"
```
with an uncertainty of 4.7 arcseconds (radius, 90% containment). This location is 153 arcseconds from the BAT on-board position, within the BAT error circle. The initial flux in the 2.5s image was 2.6e-09 erg/cm2/s (0.2-10 keV).
UVOT took a finding chart exposure of 400 seconds with the V filter starting 180 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at
```
  RA(J2000)  =	03:13:56.83 =  48.4868
  DEC(J2000) = -42:56:46.3  = -42.9462
```
with a 1-sigma error radius of about 0.5 arc sec. This position is 3.8 arc sec. from the center of the XRT error circle. The estimated magnitude is 15.4 with a 1-sigma error of about 0.5 mag. No correction has been made for the expected extinction of about 0.1 magnitudes.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 18 Mar 07 07:51:59 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     271019,   Seg_Num: 0
POINT_RA:         48.563d {+03h 14m 15s} (J2000)
POINT_DEC:       -42.975d {-42d 58' 28"} (J2000)
POINT_ROLL:      298.096d
IMG_START_DATE:  14177 TJD;    77 DOY;   07/03/18
IMG_START_TIME:  27905.73 SOD {07:45:05.73} UT,   969.6 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.553
N_STARS:         15
X_OFFSET:        870 [pixels]
Y_OFFSET:        321 [pixels]
X_MAX:           1829 [pixels]
Y_MAX:           1280 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00271019000msufc0969.fits
SUN_POSTN:       357.56d {+23h 50m 14s}   -1.06d {-01d 03' 31"}
SUN_DIST:         61.81 [deg]   Sun_angle= -3.4 [hr] (East of Sun)
MOON_POSTN:      347.52d {+23h 10m 04s}   -5.30d {-05d 18' 09"}
MOON_DIST:        65.48 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      251.11,-57.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       25.61,-57.52 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 18 Mar 07 07:52:00 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     271019,   Seg_Num: 0
GRB_RA:           48.4868d {+03h 13m 56.83s} (J2000),
                  48.5512d {+03h 14m 12.28s} (current),
                  48.0403d {+03h 12m 09.66s} (1950)
GRB_DEC:         -42.9461d {-42d 56' 45.9"} (J2000),
                 -42.9195d {-42d 55' 10.2"} (current),
                 -43.1314d {-43d 07' 53.1"} (1950)
GRB_ERROR:       0.4 [arcsec radius, statistical only]
GRB_MAG:         15.39 +/- 0.50 [mag]
FILTER:          3, V
IMG_START_DATE:  14177 TJD;    77 DOY;   07/03/18
IMG_START_TIME:  27116.00 SOD {07:31:56.00} UT,   179.9 [sec] since BAT Trigger Time
SUN_POSTN:       357.56d {+23h 50m 14s}   -1.06d {-01d 03' 31"}
SUN_DIST:         61.74 [deg]   Sun_angle= -3.4 [hr] (East of Sun)
MOON_POSTN:      347.52d {+23h 10m 04s}   -5.30d {-05d 18' 08"}
MOON_DIST:        65.41 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      251.09,-57.16 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       25.55,-57.47 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT UVOT Position Notice.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 18 Mar 07 07:52:25 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     271019,   Seg_Num: 0
POINT_RA:         48.563d {+03h 14m 15s} (J2000)
POINT_DEC:       -42.975d {-42d 58' 28"} (J2000)
POINT_ROLL:      298.096d
IMG_START_DATE:  14177 TJD;    77 DOY;   07/03/18
IMG_START_TIME:  27905.73 SOD {07:45:05.73} UT,   969.6 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.553
N_STARS:         15
X_OFFSET:        870 [pixels]
Y_OFFSET:        321 [pixels]
X_MAX:           1829 [pixels]
Y_MAX:           1280 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00271019000msufc0969.fits
SUN_POSTN:       357.56d {+23h 50m 14s}   -1.06d {-01d 03' 30"}
SUN_DIST:         61.81 [deg]   Sun_angle= -3.4 [hr] (East of Sun)
MOON_POSTN:      347.52d {+23h 10m 05s}   -5.30d {-05d 18' 01"}
MOON_DIST:        65.47 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      251.11,-57.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       25.61,-57.52 [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 18 Mar 07 07:53:12 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     271019,   Seg_Num: 0
POINT_RA:         48.563d {+03h 14m 15s} (J2000)
POINT_DEC:       -42.975d {-42d 58' 28"} (J2000)
ROLL:            298.096d
IMG_START_DATE:  14177 TJD;    77 DOY;   07/03/18
IMG_START_TIME:  27905.73 SOD {07:45:05.73} UT,   969.6 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     195896707
X_OFFSET:        1189 [pixels]
Y_OFFSET:        640 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1349
Y_GRB_POS:       800
BINNING_INDEX:   1
IM_URL:          sw00271019000msuni0969.fits
SUN_POSTN:       357.56d {+23h 50m 14s}   -1.06d {-01d 03' 29"}
SUN_DIST:         61.81 [deg]   Sun_angle= -3.4 [hr] (East of Sun)
MOON_POSTN:      347.53d {+23h 10m 07s}   -5.30d {-05d 17' 47"}
MOON_DIST:        65.47 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      251.11,-57.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       25.61,-57.52 [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 18 Mar 07 07:53:31 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     271019,   Seg_Num: 0
POINT_RA:         48.563d {+03h 14m 15s} (J2000)
POINT_DEC:       -42.975d {-42d 58' 28"} (J2000)
ROLL:            298.096d
IMG_START_DATE:  14177 TJD;    77 DOY;   07/03/18
IMG_START_TIME:  27905.73 SOD {07:45:05.73} UT,   969.6 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     195896707
X_OFFSET:        1189 [pixels]
Y_OFFSET:        640 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1349
Y_GRB_POS:       800
BINNING_INDEX:   1
IM_URL:          sw00271019000msuni0969.fits
SUN_POSTN:       357.56d {+23h 50m 14s}   -1.06d {-01d 03' 29"}
SUN_DIST:         61.81 [deg]   Sun_angle= -3.4 [hr] (East of Sun)
MOON_POSTN:      347.53d {+23h 10m 07s}   -5.30d {-05d 17' 42"}
MOON_DIST:        65.47 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      251.11,-57.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       25.61,-57.52 [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 Circular #6212
J. Cummings (GSFC/UMBC), L. Barbier (GSFC), S. D. Barthelmy (GSFC), 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), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC) on behalf of the Swift-BAT team:
Using the data set from T-120 to T+302 sec from recent telemetry downlinks, we report further analysis of BAT GRB 070318 (trigger #271019) (Cummings, et al., GCN Circ. 6210). The BAT ground-calculated position is RA, Dec = 48.486, -42.950 deg which is
```
   RA(J2000)  =  03h 13m 56.6s 
   Dec(J2000) = -42d 57' 1.1" 
```
with an uncertainty of 0.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 80%.
The mask-weighted lightcurve is a single FRED peak starting at ~T-10sec, peaking at ~T+2 sec, and returning to background at around T+120 sec. There is the possibility of weak peaks at ~T+140 and T+170 sec at the ~3-sigma level. T90 (15-350 keV) is 63 +- 3 sec (estimated error including systematics).
The time-averaged spectrum from T-1.0 to T+89.4 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.44 +- 0.08. The fluence in the 15-150 keV band is 2.3 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+1.94 sec in the 15-150 keV band is 1.6 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
GCN Circular #6213
F.E. Marshall (NASA/GSFC) and J.R. Cummings (NASA/UMBC) report on behalf of the Swift team:
The bright optical afterglow of GRB 070318 (Cummings et al., GCN Circ. 6210) is following an approximately power-law decay. At 13,000 sec. after the trigger, the magnitude in the UVOT B filter is ~19.9 with a best-fit decay index of 1.16. If this rate of decay continues, the B magnitude will be 22.3 at one day after the trigger and 23.2 a day later.
The afterglow has been detected in all 7 UVOT filters indicating that the redshift is less than ~2.
Observations with ground-based telescopes are encouraged.
GCN Circular #6214
V. La Parola, T. Mineo, B. Sbarufatti, V. Mangano, G. Cusumano (INAF-IASF Pa) report on behalf of the Swift XRT team:
We have analysed the first two orbits of Swift-XRT data on GRB 070318 (Cummings, et al., GCN Circ. 6210), with a total exposure of 427 s seconds in Window Timing (WT) mode and 33.4 ks seconds in Photon Counting (PC) mode. This provides a refined XRT position at RA,Dec=3D48.4870,-42.9454 which is:
```
RA (J2000) = 03h 13m 56.9s
Dec(J2000) = -42d 56m 43.6s
```
with an estimated error radius of 3.5 arcseconds (90% confidence). This position is 16.8 arcseconds from the BAT refined position (Cummings, et al., GCN 6212), 6.2 arcseconds from the initial XRT position, and 2.9 arcseconds from the UVOT optical candidate (Cummings, et al., GCN Circ. 6210).
The 0.3-10 keV X-ray light curve presents a bright flare peaking at about 280 s from the trigger and a second fainter peak at 200 s. The underlying light curve between 70 s and 7.5 ks can be fit with a simple power-law with a decay slope of 1.11 =B1 0.02.
The X-ray spectrum from the XRT/WT data covering up to the beginning of the bright flare is well fit by an absorbed power-law with a photon index of 1.4=B10.1 and column density of (1.5=B10.7)E21 cm**-2, higher than the Galactic column density in the direction of the source (2.5E20 cm**-2). The unabsorbed 0.3-10 keV flux for this spectrum is 1.3E-9 erg/cm**2/s. The XRT/WT spectrum of the bright flare and the XRT/PC spectrum are modelled by an absorbed power law with photon index of 1.9=B10.1 and column density of (1.3=B10.3)E21 cm**-2. The unabsorbed 0.3-10 keV flux of the bright flare is 8.2E-10 erg/cm**2/s and the one relative to the PC spectrum is 1.0E-10 erg/cm**2/s.
Assuming the X-ray emission continues to decline at the same rate, we predict a 0.3-10 keV XRT count rate of 5E-3 count/s at T+48hr, which corresponds to an observed 0.3-10 keV flux of 2.5e-13 erg/cm**2/s.
This circular is an official product of the Swift XRT Team.
GCN Circular #6215
M. Page (MSSL-UCL), M. Chester (PSU), J. R. Cummings (NASA/UMBC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began taking data in the field of GRB070318 88s after the BAT trigger (Cummings et al., GCN 6210, Marshall et al., GCN 6213). The afterglow is detected in all UVOT filters. The photometry results are given for the 7 UVOT filters below. The first White exposure was affected by the star tracker loss of lock, so results from this exposure are not reported below.
```
Filter  T+(s)   Exp(s)  Mag
White   706     10      15.53 +/- 0.08

White  6364    197      18.14 +/- 0.07

V       214    400      15.43 +/- 0.02

B       692     10      16.25 +/- 0.12
B      6159    197      18.91 +/- 0.13

U       667     19      15.89 +/- 0.09
U      5955    197      18.23 +/- 0.11

UVW1     644     19     16.89 +/- 0.18
UVW1    5750    197     19.62 +/- 0.30

UVM2     619     19     17.97 +/- 0.37
UVM2    5545    197     > 19.87 (3-sigma UL)

UVW2     870     19     18.03 +/- 0.30
UVW2    6569    197     > 20.37 (3-sigma UL)
```
T+ is the start time of the exposure since the BAT trigger. These magnitudes are not corrected for the expected extinction of E(B-V)=0.017.
GCN Circular #6216
A.O. Jaunsen (Univ. Oslo), J.P.U. Fynbo (DARK/NBI), M.I. Andersen (AIP) and P. Vreeswijk (ESO) report on behalf of a larger collaboration.
We observed the field of GRB 070318 (Cummings et al., GCN 6210, La Parola et al, GCN 6214 and Page et al. GCN 6215) with the ESO/VLT UT2 equipped with FORS1. Observations started on 2007 Mar 19.008 UT and an 1800-s spectra was acquired with the 300V grism covering a wavelength range of 3500-8500A.
We identify several emission lines from MgII, MI, FeII, MnII of which the MgII doublet 2796,2804 is the most prominent at a redshift of z=0.836.
We thank the excellent support from the ESO/Paranal staff.
GCN Circular #6217
H.-W. Chen (U Chicago), J. X. Prochaska (UCO/Lick Observatory), S. Herbert-Fort (Steward Observatory), D. Christlein (Universidad de Chile/Yale), and S. Cortes (Steward Observatory) report on behalf of a larger collaboration:
"We obtained 2x1800 sec long-slit spectra of the optical transient of GRB070318 (Cummings et al., GCN 6210), using GMOS and an the R400 grating on the Gemini south telescope. The observations started at March 19.001 UT, ~ 16.5 hours after the initial Swift trigger. The spectra covered a wavelength range from 5930 Ang through 8750 Ang. We also obtained 2700 sec long-slit spectra, using IMACS and the 300 l/mm grism on the Magellan Baade telescope. The observations started at March 19.011 UT, and the spectra cover a wavelength range from 4200 Ang through 6500 Ang. We identify MgII 2796,2803, MgI 2852, FeII 2600, and TiII 3384 lines at z=0.840 +/- 0.002, but no other apparent MgII absorption doublet. We therefore confirm the redshift reported by Jaunsen et al. (GCN 6216) as the location of the afterglow.
Further analysis is underway."
GCN Report 40.1
GCN_Report 40.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_40_1.pdf by J. Cummings at GSFC/UMBC titled: "Swift Observations of GRB 070318"
GCN Circular #6220
M.J. Page (MSSL-UCL), F.E. Marshall (NASA/GSFC) S. Immler (GSFC/USRA) S. T. Holland (CRESST/GSFC/USRA) and J.R. Cummings (GSFC/UMBC) report on behalf of the Swift/UVOT team:
The optical/UV afterglow of GRB 070318 (Cummings et al, GCN 6210) decayed to magnitude of 21.5 in the UVOT white filter in the first 24 hours after the BAT trigger, and has remained at approximately constant brightness for at least 48 hours since that time. Examination of the Supercosmos scan of the UK Schmidt sky survey plate at this location reveals no evidence for a host galaxy (the plate limit is Bj>22 mag). For the flattening of the lightcurve to be due to the host galaxy, the host galaxy would have to be very luminous (Mb ~ -22) and have an unusually blue spectrum (e.g. peaking in the U band, observer frame). It therefore seems more likely that this is an afterglow with a very unusual lightcurve.
Swift continues to monitor the afterglow. Further ground-based observations are encouraged.
GCN Circular #6296
B. E. Cobb (Yale), part of the larger SMARTS consortium, reports:
Using the ANDICAM instrument on the 1.3m telescope at CTIO, we obtained optical/IR imaging of the error region of GRB 070318 (GCN 6210, Cummings et al.) with a mid-exposure time of 2007-03-19 00:09 UT (~16.7 hrs post-burst) and again at 2007-03-21 00:07 UT (~64.6 hrs post-burst). For each set of observations, total summed exposure times amounted to 36 minutes in I and 30 minutes in J.
The afterglow of GRB 070318 (GRB 6210, Cummings et al.) is detected in the first epoch images and is observed to fade between the first and second epochs.
```
time-post
bursts (hrs)    I magnitude             J magnitude
------------------------------------------------------
16.7            19.82+/-0.07            18.29+/-0.11
64.6            20.28+/-0.12            > 18.6 (3 sigma limit)
```
Magnitudes are calibrated using Landolt standard stars in the optical and 2MASS stars in the IR.
The optical decay rate (afterglow flux proportional to t^-alpha) between 16.7 and 64.6 hours post-burst is alpha ~ 0.3 (and the IR decay is consistent with this value). This unusually shallow decay was also noted in the UVOT observations of this afterglow (GCN 6220, Page et al.).
A third late-time epoch was obtained at 2007-04-06 23:46 UT (~20 days post-burst). No source or host galaxy is detected at the position of the optical afterglow to a limiting magnitude of I > 21.7 and J > 19.2. This indicates that the decay rate of the afterglow must have steepened sometime after our second epoch observation.
GCN Report 40.2
GCN_Report 40.2 has been posted: http://gcn.gsfc.nasa.gov/reports/report_40_2.pdf by J. Cummings at GSFC/UMBC titled: "Final Swift Observations of GRB 070318"
1301.6204 from 29 Jan 13
J. Cant� et al.: Shock Dynamics In Relativistic Jets
We present a formalism of the dynamics of internal shocks in relativistic jets where the source has a time-dependent injection velocity and mass-loss rate. The variation of the injection velocity produces a two-shock wave structure, the working surface, that moves along the jet. This new formalism takes into account the fact that momentum conservation is not valid for relativistic flows where the relativistic mass lost by radiation must be taken into account, in contrast to the classic regime. We find analytic solutions for the working surface velocity and radiated energy for the particular case of a step function variability of the injection parameters. We model two cases: a pulse of fast material and a pulse of slow material (with respect to the mean flow). Applying these models to gamma ray burst light curves, one can determine the ratio of the Lorentz factors gamma_2 / gamma_1 and the ratio of the mass-loss rates dot{m_2} / dot{m_1} of the upstream and downstream flows. As an example, we apply this model to the sources GRB 080413B and GRB 070318 and find the values of these ratios. Assuming a Lorentz factor gamma_1=100, we further estimate jet mass-loss rates between dot{m_1} ~ 10^{-5}-1 Msun.yr^{-1}. We also calculate the fraction of the injected mass lost by radiation. For GRB 070318 this fraction is ~7%. In contrast, for GRB 080413B this fraction is larger than 50%; in this case radiation losses clearly affect the dynamics of the internal shocks.

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Jochen Greiner, last update: 29-Jan-2013 [Disclaimer]