Gamma-ray Burst 120404A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Apr 12 12:51:47 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     519380,   Seg_Num: 0
GRB_RA:          235.012d {+15h 40m 03s} (J2000),
                 235.156d {+15h 40m 37s} (current),
                 234.423d {+15h 37m 42s} (1950)
GRB_DEC:         +12.882d {+12d 52' 54"} (J2000),
                 +12.843d {+12d 50' 34"} (current),
                 +13.043d {+13d 02' 33"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       17004 [cnts]    Image_Peak=499 [image_cnts]
TRIGGER_DUR:     4.096 [sec] 
TRIGGER_INDEX:   298     E_range: 25-100 keV
BKG_INTEN:       147052 [cnts]
BKG_TIME:        46207.93 SOD {12:50:07.93} UT
BKG_DUR:         40 [sec]
GRB_DATE:        16021 TJD;    95 DOY;   12/04/04
GRB_TIME:        46262.39 SOD {12:51:02.39} UT
GRB_PHI:         -175.82 [deg]
GRB_THETA:        41.69 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     9.11 [sigma]
IMAGE_SIGNIF:    11.42 [sigma]
MERIT_PARAMS:     +1  +0  +0  +2  +2  +1  +0  +0 +70  +0 
SUN_POSTN:        13.96d {+00h 55m 49s}   +5.97d {+05d 58' 05"}
SUN_DIST:        134.95 [deg]   Sun_angle= 9.3 [hr] (West of Sun)
MOON_POSTN:      163.14d {+10h 52m 34s}   +1.73d {+01d 43' 42"}
MOON_DIST:        72.08 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:       21.60, 48.15 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      229.05, 31.48 [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 = 189.91,-8.91 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Apr 12 12:53:46 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     519380,   Seg_Num: 0
GRB_RA:          235.0096d {+15h 40m 02.30s} (J2000),
                 235.1539d {+15h 40m 36.92s} (current),
                 234.4214d {+15h 37m 41.13s} (1950)
GRB_DEC:         +12.8838d {+12d 53' 01.6"} (J2000),
                 +12.8447d {+12d 50' 41.0"} (current),
                 +13.0446d {+13d 02' 40.6"} (1950)
GRB_ERROR:       5.9 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       7.34e-10 [erg/cm2/sec]
GRB_SIGNIF:      6.00 [sigma]
IMG_START_DATE:  16021 TJD;    95 DOY;   12/04/04
IMG_START_TIME:  46392.42 SOD {12:53:12.42} UT,   130.0 [sec] since BAT Trigger Time
TAM[0-3]:        327.68 237.21 261.52 243.81
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:        13.96d {+00h 55m 50s}   +5.97d {+05d 58' 07"}
SUN_DIST:        134.95 [deg]   Sun_angle= 9.3 [hr] (West of Sun)
MOON_POSTN:      163.16d {+10h 52m 39s}   +1.72d {+01d 43' 15"}
MOON_DIST:        72.06 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:       21.60, 48.15 [deg] galactic lon,lat of the burst
ECL_COORDS:      229.04, 31.48 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 0.16 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Apr 12 12:54:00 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     519380,   Seg_Num: 0
GRB_RA:          235.0096d {+15h 40m 02.3s} (J2000),
                 235.1539d {+15h 40m 36.9s} (current),
                 234.4214d {+15h 37m 41.1s} (1950)
GRB_DEC:         +12.8838d {+12d 53' 01.6"} (J2000),
                 +12.8447d {+12d 50' 41.0"} (current),
                 +13.0446d {+13d 02' 40.6"} (1950)
GRB_ERROR:       5.8 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       36 [cnts]
IMG_START_DATE:  16021 TJD;    95 DOY;   12/04/04
IMG_START_TIME:  46392.42 SOD {12:53:12.42} UT,   130.0 [sec] since BAT Trigger Time
CENTROID_X:      339.29,  raw= 339  [pixels]
CENTROID_Y:      342.72,  raw= 343  [pixels]
ROLL:            67.65 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   105.42
GRB_POS_XRT_Z:   83.91
IMAGE_URL:       sw00519380000msxps_rw.img
SUN_POSTN:        13.96d {+00h 55m 50s}   +5.97d {+05d 58' 07"}
SUN_DIST:        134.95 [deg]   Sun_angle= 9.3 [hr] (West of Sun)
MOON_POSTN:      163.16d {+10h 52m 39s}   +1.72d {+01d 43' 12"}
MOON_DIST:        72.06 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:       21.60, 48.15 [deg] galactic lon,lat of the burst
ECL_COORDS:      229.04, 31.48 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Apr 12 12:54:07 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     519380,   Seg_Num: 0
GRB_RA:          235.0096d {+15h 40m 02.3s} (J2000),
                 235.1539d {+15h 40m 36.9s} (current),
                 234.4214d {+15h 37m 41.1s} (1950)
GRB_DEC:         +12.8838d {+12d 53' 01.6"} (J2000),
                 +12.8447d {+12d 50' 41.0"} (current),
                 +13.0446d {+13d 02' 40.6"} (1950)
GRB_ERROR:       5.8 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       36 [cnts]
IMG_START_DATE:  16021 TJD;    95 DOY;   12/04/04
IMG_START_TIME:  46392.42 SOD {12:53:12.42} UT,   130.0 [sec] since BAT Trigger Time
CENTROID_X:      339.29,  raw= 339  [pixels]
CENTROID_Y:      342.72,  raw= 343  [pixels]
ROLL:            67.65 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   105.42
GRB_POS_XRT_Z:   83.91
IMAGE_URL:       sw00519380000msxps_rw.img
SUN_POSTN:        13.96d {+00h 55m 50s}   +5.97d {+05d 58' 07"}
SUN_DIST:        134.95 [deg]   Sun_angle= 9.3 [hr] (West of Sun)
MOON_POSTN:      163.16d {+10h 52m 40s}   +1.72d {+01d 43' 11"}
MOON_DIST:        72.06 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:       21.60, 48.15 [deg] galactic lon,lat of the burst
ECL_COORDS:      229.04, 31.48 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Apr 12 12:54:50 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     519380,   Seg_Num: 0
GRB_RA:          235.012d {+15h 40m 03s} (J2000),
                 235.156d {+15h 40m 37s} (current),
                 234.423d {+15h 37m 42s} (1950)
GRB_DEC:         +12.882d {+12d 52' 54"} (J2000),
                 +12.843d {+12d 50' 34"} (current),
                 +13.043d {+13d 02' 33"} (1950)
GRB_DATE:        16021 TJD;    95 DOY;   12/04/04
GRB_TIME:        46262.39 SOD {12:51:02.39} UT
TRIGGER_INDEX:   298
GRB_PHI:         -175.82 [deg]
GRB_THETA:        41.69 [deg]
DELTA_TIME:      -5.00 [sec]
TRIGGER_DUR:     4.096 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     9.11 [sigma]
IMAGE_SIGNIF:    11.42 [sigma]
LC_URL:          sw00519380000msb.lc
SUN_POSTN:        13.96d {+00h 55m 50s}   +5.97d {+05d 58' 08"}
SUN_DIST:        134.95 [deg]   Sun_angle= 9.3 [hr] (West of Sun)
MOON_POSTN:      163.17d {+10h 52m 41s}   +1.72d {+01d 43' 01"}
MOON_DIST:        72.06 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:       21.60, 48.15 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      229.05, 31.48 [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 = 189.91,-8.91 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Apr 12 12:56:27 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     519380,   Seg_Num: 0
POINT_RA:        235.044d {+15h 40m 10s} (J2000)
POINT_DEC:       +12.866d {+12d 51' 57"} (J2000)
POINT_ROLL:      67.647d
IMG_START_DATE:  16021 TJD;    95 DOY;   12/04/04
IMG_START_TIME:  46400.96 SOD {12:53:20.96} UT,   138.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.967
N_STARS:         48
X_OFFSET:        240 [pixels]
Y_OFFSET:        456 [pixels]
X_MAX:           1199 [pixels]
Y_MAX:           1415 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00519380000msufc0138.fits
SUN_POSTN:        13.96d {+00h 55m 50s}   +5.97d {+05d 58' 10"}
SUN_DIST:        134.93 [deg]   Sun_angle= 9.3 [hr] (West of Sun)
MOON_POSTN:      163.19d {+10h 52m 45s}   +1.71d {+01d 42' 39"}
MOON_DIST:        72.07 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:       21.60, 48.11 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      229.09, 31.47 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Apr 12 12:56:51 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     519380,   Seg_Num: 0
POINT_RA:        235.044d {+15h 40m 10s} (J2000)
POINT_DEC:       +12.866d {+12d 51' 57"} (J2000)
POINT_ROLL:      67.647d
IMG_START_DATE:  16021 TJD;    95 DOY;   12/04/04
IMG_START_TIME:  46400.96 SOD {12:53:20.96} UT,   138.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.967
N_STARS:         48
X_OFFSET:        240 [pixels]
Y_OFFSET:        456 [pixels]
X_MAX:           1199 [pixels]
Y_MAX:           1415 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00519380000msufc0138.fits
SUN_POSTN:        13.96d {+00h 55m 50s}   +5.97d {+05d 58' 10"}
SUN_DIST:        134.93 [deg]   Sun_angle= 9.3 [hr] (West of Sun)
MOON_POSTN:      163.19d {+10h 52m 46s}   +1.71d {+01d 42' 34"}
MOON_DIST:        72.07 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:       21.60, 48.11 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      229.09, 31.47 [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:     Wed 04 Apr 12 12:57:49 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     519380,   Seg_Num: 0
POINT_RA:        235.044d {+15h 40m 10s} (J2000)
POINT_DEC:       +12.866d {+12d 51' 57"} (J2000)
ROLL:            67.647d
IMG_START_DATE:  16021 TJD;    95 DOY;   12/04/04
IMG_START_TIME:  46400.96 SOD {12:53:20.96} UT,   138.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     355236809
X_OFFSET:        553 [pixels]
Y_OFFSET:        764 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       713
Y_GRB_POS:       924
BINNING_INDEX:   1
IM_URL:          sw00519380000msuni0147.fits
SUN_POSTN:        13.96d {+00h 55m 50s}   +5.97d {+05d 58' 11"}
SUN_DIST:        134.93 [deg]   Sun_angle= 9.3 [hr] (West of Sun)
MOON_POSTN:      163.20d {+10h 52m 48s}   +1.71d {+01d 42' 21"}
MOON_DIST:        72.06 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:       21.60, 48.11 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      229.09, 31.47 [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:     Wed 04 Apr 12 12:58:05 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     519380,   Seg_Num: 0
POINT_RA:        235.044d {+15h 40m 10s} (J2000)
POINT_DEC:       +12.866d {+12d 51' 57"} (J2000)
ROLL:            67.647d
IMG_START_DATE:  16021 TJD;    95 DOY;   12/04/04
IMG_START_TIME:  46400.96 SOD {12:53:20.96} UT,   138.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     355236809
X_OFFSET:        553 [pixels]
Y_OFFSET:        764 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       713
Y_GRB_POS:       924
BINNING_INDEX:   1
IM_URL:          sw00519380000msuni0147.fits
SUN_POSTN:        13.96d {+00h 55m 50s}   +5.97d {+05d 58' 11"}
SUN_DIST:        134.93 [deg]   Sun_angle= 9.3 [hr] (West of Sun)
MOON_POSTN:      163.20d {+10h 52m 48s}   +1.70d {+01d 42' 18"}
MOON_DIST:        72.06 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:       21.60, 48.11 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      229.09, 31.47 [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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Apr 12 12:59:09 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     519380,   Seg_Num: 0
GRB_RA:          235.0095d {+15h 40m 02.28s} (J2000),
                 235.1538d {+15h 40m 36.90s} (current),
                 234.4213d {+15h 37m 41.11s} (1950)
GRB_DEC:         +12.8850d {+12d 53' 05.9"} (J2000),
                 +12.8459d {+12d 50' 45.3"} (current),
                 +13.0458d {+13d 02' 44.9"} (1950)
GRB_ERROR:       0.7 [arcsec radius, statistical only]
GRB_MAG:         19.37 +/- 0.16 [mag]
FILTER:          10, White
IMG_START_DATE:  16021 TJD;    95 DOY;   12/04/04
IMG_START_TIME:  46400.00 SOD {12:53:20.00} UT,   137.6 [sec] since BAT Trigger Time
SUN_POSTN:        13.96d {+00h 55m 51s}   +5.97d {+05d 58' 12"}
SUN_DIST:        134.96 [deg]   Sun_angle= 9.3 [hr] (West of Sun)
MOON_POSTN:      163.21d {+10h 52m 51s}   +1.70d {+01d 42' 03"}
MOON_DIST:        72.02 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:       21.60, 48.15 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      229.04, 31.48 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT UVOT Position Notice.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The UVOT position is 4.3 arcsec from the XRT position.  
COMMENTS:        Result based on Genie data.  
COMMENTS:        Notice generated automatically.

GCN Circular #13208
G. Stratta (ASDC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), S. Campana (INAF-OAB), V. D'Elia (ASDC), P. A. Evans (U Leicester), C. Guidorzi (U Ferrara), S. T. Holland (STScI), E. A. Hoversten (PSU), J. A. Kennea (PSU), A. Y. Lien (NASA/GSFC/ORAU), V. Mangano (INAF-IASFPA), F. E. Marshall (NASA/GSFC), A. Maselli (INAF-IASFPA), A. Melandri (INAF-OAB), P. T. O'Brien (U Leicester), C. Pagani (U Leicester), K. L. Page (U Leicester), P. Romano (INAF-IASFPA), R. L. C. Starling (U Leicester), M. C. Stroh (PSU) and B.-B. Zhang (PSU) report on behalf of the Swift Team:
At 12:51:02 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 120404A (trigger=519380). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 235.012, +12.882 which is
```
   RA(J2000)  =  15h 40m 03s
   Dec(J2000) = +12d 52' 54"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single symmetric peak with a duration of about 35 sec. The peak count rate was ~1800 counts/sec (15-350 keV), at ~5 sec after the trigger.
The XRT began observing the field at 12:53:12.4 UT, 130.0 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 235.00884, 12.88446 which is equivalent to:
```
   RA(J2000)  = 15h 40m 02.12s
   Dec(J2000) = +12d 53' 04.1"
```
with an uncertainty of 4.1 arcseconds (radius, 90% containment). This location is 14 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. We cannot determine whether the source is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 3.42 x 10^20 cm^-2 (Kalberla et al. 2005).
The initial flux in the 2.5 s image was 7.34e-10 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 138 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 15:40:02.29 = 235.00956 DEC(J2000) = +12:53:06.3 = 12.88508 with a 90%-confidence error radius of about 0.65 arc sec. This position is 4.6 arc sec. from the center of the XRT error circle. The estimated magnitude is 19.37 with a 1-sigma error of about 0.16. No correction has been made for the expected extinction corresponding to E(B-V) of 0.05.
Burst Advocate for this burst is G. Stratta (giulia.stratta AT asdc.asi.it). 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:     Wed 04 Apr 12 13:04:15 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     519380,   Seg_Num: 0
POINT_RA:        235.042d {+15h 40m 10s} (J2000)
POINT_DEC:       +12.865d {+12d 51' 54"} (J2000)
POINT_ROLL:      67.649d
IMG_START_DATE:  16021 TJD;    95 DOY;   12/04/04
IMG_START_TIME:  46613.05 SOD {12:56:53.05} UT,   350.7 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.564
N_STARS:         23
X_OFFSET:        233 [pixels]
Y_OFFSET:        444 [pixels]
X_MAX:           1192 [pixels]
Y_MAX:           1403 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw00519380000msufc0350.fits
SUN_POSTN:        13.96d {+00h 55m 51s}   +5.97d {+05d 58' 17"}
SUN_DIST:        134.94 [deg]   Sun_angle= 9.3 [hr] (West of Sun)
MOON_POSTN:      163.26d {+10h 53m 02s}   +1.68d {+01d 40' 55"}
MOON_DIST:        72.01 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:       21.60, 48.11 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      229.08, 31.47 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Apr 12 13:05:30 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     519380,   Seg_Num: 0
POINT_RA:        235.042d {+15h 40m 10s} (J2000)
POINT_DEC:       +12.865d {+12d 51' 54"} (J2000)
ROLL:            67.649d
IMG_START_DATE:  16021 TJD;    95 DOY;   12/04/04
IMG_START_TIME:  46613.05 SOD {12:56:53.05} UT,   350.7 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     355237021
X_OFFSET:        553 [pixels]
Y_OFFSET:        764 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       713
Y_GRB_POS:       924
BINNING_INDEX:   1
IM_URL:          sw00519380000msuni0359.fits
SUN_POSTN:        13.96d {+00h 55m 52s}   +5.97d {+05d 58' 18"}
SUN_DIST:        134.94 [deg]   Sun_angle= 9.3 [hr] (West of Sun)
MOON_POSTN:      163.27d {+10h 53m 05s}   +1.68d {+01d 40' 38"}
MOON_DIST:        72.00 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:       21.60, 48.11 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      229.08, 31.47 [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:     Wed 04 Apr 12 13:05:21 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     519380,   Seg_Num: 0
GRB_RA:          235.0097d {+15h 40m 02.32s} (J2000),
                 235.1540d {+15h 40m 36.95s} (current),
                 234.4215d {+15h 37m 41.15s} (1950)
GRB_DEC:         +12.8844d {+12d 53' 03.8"} (J2000),
                 +12.8453d {+12d 50' 43.2"} (current),
                 +13.0452d {+13d 02' 42.7"} (1950)
GRB_ERROR:       2.3 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  16021 TJD;    95 DOY;   12/04/04
IMG_START_TIME:  46505.00 SOD {12:55:05.00} UT,   242.6 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        13.96d {+00h 55m 51s}   +5.97d {+05d 58' 18"}
SUN_DIST:        134.96 [deg]   Sun_angle= 9.3 [hr] (West of Sun)
MOON_POSTN:      163.27d {+10h 53m 05s}   +1.68d {+01d 40' 40"}
MOON_DIST:        71.97 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:       21.60, 48.15 [deg] galactic lon,lat of the burst
ECL_COORDS:      229.04, 31.48 [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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Apr 12 13:05:43 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     519380,   Seg_Num: 0
POINT_RA:        235.042d {+15h 40m 10s} (J2000)
POINT_DEC:       +12.865d {+12d 51' 54"} (J2000)
ROLL:            67.649d
IMG_START_DATE:  16021 TJD;    95 DOY;   12/04/04
IMG_START_TIME:  46613.05 SOD {12:56:53.05} UT,   350.7 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     355237021
X_OFFSET:        553 [pixels]
Y_OFFSET:        764 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       713
Y_GRB_POS:       924
BINNING_INDEX:   1
IM_URL:          sw00519380000msuni0359.fits
SUN_POSTN:        13.96d {+00h 55m 52s}   +5.97d {+05d 58' 18"}
SUN_DIST:        134.94 [deg]   Sun_angle= 9.3 [hr] (West of Sun)
MOON_POSTN:      163.27d {+10h 53m 06s}   +1.68d {+01d 40' 35"}
MOON_DIST:        72.00 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:       21.60, 48.11 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      229.08, 31.47 [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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Apr 12 13:10:39 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     519380,   Seg_Num: 0
POINT_RA:        235.042d {+15h 40m 10s} (J2000)
POINT_DEC:       +12.865d {+12d 51' 53"} (J2000)
POINT_ROLL:      67.649d
IMG_START_DATE:  16021 TJD;    95 DOY;   12/04/04
IMG_START_TIME:  47142.03 SOD {13:05:42.03} UT,   879.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.026
N_STARS:         124
X_OFFSET:        0 [pixels]
Y_OFFSET:        204 [pixels]
X_MAX:           1439 [pixels]
Y_MAX:           1643 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00519380000msufc0879.fits
SUN_POSTN:        13.97d {+00h 55m 52s}   +5.97d {+05d 58' 23"}
SUN_DIST:        134.94 [deg]   Sun_angle= 9.3 [hr] (West of Sun)
MOON_POSTN:      163.32d {+10h 53m 17s}   +1.66d {+01d 39' 29"}
MOON_DIST:        71.96 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:       21.60, 48.11 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      229.08, 31.47 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Apr 12 13:11:04 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     519380,   Seg_Num: 0
POINT_RA:        235.042d {+15h 40m 10s} (J2000)
POINT_DEC:       +12.865d {+12d 51' 53"} (J2000)
POINT_ROLL:      67.649d
IMG_START_DATE:  16021 TJD;    95 DOY;   12/04/04
IMG_START_TIME:  47142.03 SOD {13:05:42.03} UT,   879.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.026
N_STARS:         124
X_OFFSET:        0 [pixels]
Y_OFFSET:        204 [pixels]
X_MAX:           1439 [pixels]
Y_MAX:           1643 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00519380000msufc0879.fits
SUN_POSTN:        13.97d {+00h 55m 52s}   +5.97d {+05d 58' 23"}
SUN_DIST:        134.94 [deg]   Sun_angle= 9.3 [hr] (West of Sun)
MOON_POSTN:      163.32d {+10h 53m 18s}   +1.66d {+01d 39' 24"}
MOON_DIST:        71.95 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:       21.60, 48.11 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      229.08, 31.47 [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:     Wed 04 Apr 12 13:11:57 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     519380,   Seg_Num: 0
POINT_RA:        235.042d {+15h 40m 10s} (J2000)
POINT_DEC:       +12.865d {+12d 51' 53"} (J2000)
ROLL:            67.649d
IMG_START_DATE:  16021 TJD;    95 DOY;   12/04/04
IMG_START_TIME:  47142.03 SOD {13:05:42.03} UT,   879.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     355237550
X_OFFSET:        559 [pixels]
Y_OFFSET:        763 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       719
Y_GRB_POS:       923
BINNING_INDEX:   1
IM_URL:          sw00519380000msuni0888.fits
SUN_POSTN:        13.97d {+00h 55m 52s}   +5.97d {+05d 58' 24"}
SUN_DIST:        134.94 [deg]   Sun_angle= 9.3 [hr] (West of Sun)
MOON_POSTN:      163.33d {+10h 53m 20s}   +1.65d {+01d 39' 12"}
MOON_DIST:        71.95 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:       21.60, 48.11 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      229.08, 31.47 [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:     Wed 04 Apr 12 13:12:12 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     519380,   Seg_Num: 0
POINT_RA:        235.042d {+15h 40m 10s} (J2000)
POINT_DEC:       +12.865d {+12d 51' 53"} (J2000)
ROLL:            67.649d
IMG_START_DATE:  16021 TJD;    95 DOY;   12/04/04
IMG_START_TIME:  47142.03 SOD {13:05:42.03} UT,   879.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     355237550
X_OFFSET:        559 [pixels]
Y_OFFSET:        763 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       719
Y_GRB_POS:       923
BINNING_INDEX:   1
IM_URL:          sw00519380000msuni0888.fits
SUN_POSTN:        13.97d {+00h 55m 53s}   +5.97d {+05d 58' 25"}
SUN_DIST:        134.94 [deg]   Sun_angle= 9.3 [hr] (West of Sun)
MOON_POSTN:      163.33d {+10h 53m 20s}   +1.65d {+01d 39' 08"}
MOON_DIST:        71.94 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:       21.60, 48.11 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      229.08, 31.47 [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 Circular #13209
C. Guidorzi (U. Ferrara), A. Melandri (INAF-OAB), J. Japelj (U. Ljubljana) on behalf of a larger collaboration report:
"The 2-m Faulkes Telescope North robotically followed up GRB 120404A (Stratta et al., GCN Circ. 13208) at 12:55:03 UT, corresponding to 4 min after the GRB trigger time. We clearly detect the optical afterglow candidate by Swift-UVOT (GCN 13208) with a magnitude of 18.8 +- 0.3 in the R filter in a 10-s exposure frame, calibrated against nearby USNOB-1 field stars.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Apr 12 13:04:28 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     519380,   Seg_Num: 0
POINT_RA:        235.042d {+15h 40m 10s} (J2000)
POINT_DEC:       +12.865d {+12d 51' 54"} (J2000)
POINT_ROLL:      67.649d
IMG_START_DATE:  16021 TJD;    95 DOY;   12/04/04
IMG_START_TIME:  46613.05 SOD {12:56:53.05} UT,   350.7 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.564
N_STARS:         23
X_OFFSET:        233 [pixels]
Y_OFFSET:        444 [pixels]
X_MAX:           1192 [pixels]
Y_MAX:           1403 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw00519380000msufc0350.fits
SUN_POSTN:        13.96d {+00h 55m 51s}   +5.97d {+05d 58' 17"}
SUN_DIST:        134.94 [deg]   Sun_angle= 9.3 [hr] (West of Sun)
MOON_POSTN:      163.26d {+10h 53m 03s}   +1.68d {+01d 40' 52"}
MOON_DIST:        72.01 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:       21.60, 48.11 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      229.08, 31.47 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN Circular #13210
V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk
E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, A.Belinski, N.Tyurina, N.Shatskiy, P.Balanutsa, D.Zimnukhov, A.Kuznetsov, V.V.Chazov, A.Kuznetsov, A.Sankovich Moscow Lomonosov State University, Sternberg Astronomical Institute,
K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University
A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory
V.Krushinski, I.Zalozhnich, A. Popov, A. Bourdanov, A. Punanova Ural Federal University
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)
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Blagoveschensk was pointed to the GRB120404A 24 sec s after notice time and 71 sec after GRB time at 2012-04-04 12:52:13.917 UT. On our first (10s exposure) set we haven`t found optical transient within SWIFT error-box (Stratta et al., GCN 13208). The GRB was at 15 degrees under horizont. The 5-sigma upper limit has been about 15.3 mag. The message may be cited.
The message may be cited.
GCN Circular #13211
Y. Saito, Y. Aoki, S. Song, M. Hayashi, K. Kawakami, K. Tokoyoda, R. Usui, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration:
We observed GRB 120404A (Stratta et al., GCN Circular 13208) with the optical three color (g, Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan.
We started the observation 84 sec after the BAT trigger from 2012-04-04 12:52:24.8 UT. And we did not find any new point source within the XRT error circle in the three bands. The results of photometry (3sigma upper limits) are listed below.
The photon flux were calibrated against GSC2.3 catalog.
```
T0+[sec]      MID-UT     T-EXP[sec]       g'              Rc           Ic
----------------------------------------------------------------------------------------------------
   219         12:54:40          270           > 15.4       > 16.1     > 16.7
----------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst [sec]
T-EXP: Total Exposure time [sec]
```
GCN Circular #13213
A. Cucchiara (UCSC/UCO Lick), on behalf of a larger collaboration reports:
On April 4.58 UT (~60 minutes after the BAT trigger) we observed the field of GRB 120404A (Stratta et al., GCN 13208) using GMOS Spectrograph on the Gemini-North 8-m telescope.
The optical afterglow is clearly detected in our r-band acquisition image. We performed 2x900s spectroscopic observations of the optical afterglow using the B600 grating centered at 6500 Angstrom (covering the range 5100-7900 A). The spectrum reveals several absorption features, including FeII2586,2600, MgII2796,2803 at a common redshift of 1.633. Other features indicate at least one MgII intervening system at z=1.101
We therefore suggest that the redshift of GRB 120404A is z=1.633.
We thank the Gemini-North staff for their prompt support.
GCN Circular #13217
A. Cucchiara (UCSC/UCO Lick), N.R. Tanvir (U. of Leicester) report on behalf of a larger collaboration:
We re-analyzed the GMOS spectra of GRB 120404A presented in GCN 13213. Based on further analysis we report a corrected redshift for the GRB of z=2.876.
This new value is based on the identification of SiIV1393,1403, CIV1550,AlIII1855,1963, CII1335, CII*1335, SiII1527, SiII*1533, SiII1808. We note that the CIV1448 line at this redshift is partly covered by the GMOS chip gap.
At least four different intervening systems are identified at the following redshifts:
```
z1=2.551 (based on CIV1548,1550 doublet)
z2=1.776 (based on MgII2796,2803 doublet)
z3=1.633 (based on MgII2796,2803 doublet)
z4=1.101 (based on MgII2796,2803 doublet)
```
We encourage further spectroscopic observations and apologize for any inconvenience the previous redshift determination may have caused.
GCN Circular #13218
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 852 s of XRT Photon Counting mode data and 1 UVOT images for GRB 120404A, 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 = 235.00951, +12.88471 which is equivalent to:
```
RA (J2000): 15h 40m 2.28s
Dec (J2000): +12d 53' 04.9"
```
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 #13220
T. N. Ukwatta (MSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (OSU), G. Stratta (ASDC), J. Tueller (GSFC) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from recent telemetry downlinks, we report further analysis of BAT GRB 120404A (trigger #519380) (Strata, et al., GCN Circ. 13208). The BAT ground-calculated position is RA, Dec = 235.002, 12.883 deg, which is
```
   RA(J2000)  =  15h 40m 00.4s 
   Dec(J2000) = +12d 52' 57.3" 
```
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 49%.
The mask-weighted light curve shows several overlapping peaks starting at ~T-20 sec, peaking at ~T+4 sec, and ending at ~T+80 sec. T90 (15-350 keV) is 38.7 +- 4.1 sec (estimated error including systematics).
The time-averaged spectrum from T-7.31 to T+38.45 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.85 +- 0.13. The fluence in the 15-150 keV band is 1.6 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+3.29 sec in the 15-150 keV band is 1.2 +- 0.2 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/519380/BA/
GCN Circular #13221
L.P. Xin, J. Y.Wei, Y.L. Qiu, J. Wang, J.S. Deng, C. Wu, X. H. Han on behalf of EAFON report:
We began to observe GRB 120404A (Stratta et al., GCN Circ. 13208) with Xinglong TNT telescope in R-band at 19:33:05(UT), 6.7 hours after the burst. The optical counterpart (Stratta et al., GCN Circ. 13208, Guidorzi et al. GCN Circ. 13209) was marginal detected with a brightness of 20.3 +/- 0.2 mag calibrated to USNO B1.0 R2 mag, at the mean time of 7.4 hours after the burst.
Combined with the report by Guidorzi et al. ( GCN Circ. 13209 ), the brightness of this burst decayed by 1.5 magnitude in R-band during 4 min and 7.4 hour after the burst, corresponding to a shallow decay index of about 0.3 during this phase.
Further observations are encouraged.
This message may be cited.
For more information about Xinglong GRBs Follow-up observations, please visit the website: http://www.xinglong-naoc.org:8080/grb/index.html
We thank Liang Ma for performing these observations.
GCN Circular #13222
P.A. Evans (U. Leicester), O.M. Littlejohns (U. Leicester), V. Mangano (INAF-IASFPA), A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), M.C. Stroh (PSU), D.N. Burrows (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester) and G. Stratta report on behalf of the Swift-XRT team:
We have analysed 7.7 ks of XRT data for GRB 120404A (Stratta et al. GCN Circ. 13208), from 119 s to 23.3 ks after the BAT trigger. The data comprise 109 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 enhanced XRT position for this burst was given by Osborne et al. (GCN. Circ 13218).
The light curve can be modelled with a series of power-law decays. The initial decay index is alpha=2.15 (+0.18, -0.17). At T+544 s the decay flattens to an alpha of 0.1 (+0.4, -0.6) before breaking again at T+2930 s to a final decay with index alpha=1.83 (+0.21, -0.19).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.72 (+0.14, -0.13). The best-fitting absorption column is 2.3 (+4.7, -2.3) x 10^21 cm^-2, at a redshift of 2.87, in addition to the Galactic value of 3.4 x 10^20 cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index of 1.90 (+/-0.12) and a best-fitting absorption column of 4.5 (+4.3, -4.0) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.7 x 10^-11 (4.3 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Galactic foreground: 3.4 x 10^20 cm^-2
Intrinsic column:    4.5 (+4.3, -4.0) x 10^21 cm^-2 at z=2.87
Photon index:	     1.90 (+/-0.12)
```
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00519380.
This circular is an official product of the Swift-XRT team.
GCN Circular #13224
D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ), S. Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of the MITSuME collaboration:
We observed the field of GRB 120404A (Stratta et al., GCNC 13208) with the optical three color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory.
The observation started on 2012-04-04 17:41:39 UT (~4.8 h after the burst). We detected the previously reported afterglow (Guidorzi et al., GCNC 13209) in Rc and Ic bands.
Photometric results of the OT are listed below. We used SDSS catalog for flux calibration.
```
#T0+[day]  MID-UT    T-EXP[sec]   g'     Rc  Rc_err    Ic  Ic_err
----------------------------------------------------------------------
0.24381    18:42:07   5760.0    >20.4   20.2  0.3     19.1  0.2
----------------------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
```
GCN Circular #13225
D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe (IAO, NAOJ), K. Yanagisawa (OAO, NAOJ), S.Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of the MITSuME collaboration:
We observed the field of GRB 120404A (Stratta et al., GCNC 13208) with the optical three color (g', Rc and Ic) CCD camera attached to the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory.
The observation started on 2012-04-04 14:31:32 UT (~1.7 h after the burst). We detected the previously reported afterglow (Guidorzi et al., GCNC 13209) in only Ic band.
Photometric results of the OT are listed below. We used SDSS catalog for flux calibration.
```
#T0+[day]  MID-UT    T-EXP[sec]   g'     Rc    Ic  Ic_err
----------------------------------------------------------------------
0.09215    15:03:44   1080.0    >18.6  >18.7  17.5  0.2
----------------------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
```
GCN Circular #13226
A. A. Breeveld (MSSL-UCL) and G. Stratta (ASDC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 120404A 139 s after the BAT trigger (Stratta et al., GCN Circ. 13208). A source at the UVOT position given in Stratta et al., GCN Circ. 13208,=20 and consistent with the enhanced XRT position (Osborne et al., GCN Circ.=20 13218), is detected in the initial UVOT exposures. The source is only=20 seen in the optical filters and rises initially and then fades. The fact=20 that the source is not detected in the UV filters is consistent with the=20 redshift of z=3D2.876 reported by Cucchiara et al., GCN Circ. 13217.
Preliminary detections and 3-sigma upper limits using the UVOT=20 photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for=20 the early exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white              139          288          147         19.43 =B1 0.12
v                 4734         4934          197         17.69 =B1 0.10
b                  606         1178           58         19.22 =B1 0.28
u                  351         1327          304         19.90 =B1 0.19
w1                 729         6779          452        >20.3
m2                 704         6574          432        >21.5
w2                 656        11408         1179        >22.1
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) =3D 0.05 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #13227
V. D'Elia (INAF-OAR and ASI-ASDC), Paolo Goldoni (APC/U. Paris 7 and SAp/CEA), Daniele Malesani (DARK/NBI), Nial R. Tanvir (U. of Leicester), Johan P. U. Fynbo (DARK/NBI) and Andrea Melandri (INAF-OAB) and report on behalf of a larger collaboration:
We observed the optical/NIR afterglow of the Swift GRB 120404A (Stratta et al., GCN 13208; Guidorzi et al., GCN 13209) with the VLT/UT2 equipped with the X-shooter spectrograph. Observations started around 04:30 UT on 2012-04-05, which is roughly 16 hr after the trigger.
In the acquisition frame (taken 15.9 hr after the GRB), the afterglow is detected at low S/N. Comparison with two closeby SDSS stars yields R ~ 21.3 (Vega), with a systematic uncertainty of ~0.3 mag.
Four exposures in a nodding pattern with an integration time of 2400 s each were obtained in poor sky conditions. The spectrum covers an approximate wavelength range between 3000 and 25000 AA. The slit width was set to 1" in the ultra-violet/blue arm, and 0.9" in the visual and near-infrared arms, resulting in a resolving power range of approximately 4500-7500.
Preliminary reduction of the spectrum shows a weak continuum with a trough at ~4720 AA, which we identify as Ly-alpha. We also detect faint absorption lines of OI 1302 and SiIV 1393/1402 at a common redshift of ~2.88. This confirms the redshift determination by Gemini-N (Cucchiara et al., GCN 13217). A second dip matching Lya at z=2.55 is also marginally detected. This is consistent with the CIV intervening absorber reported in Cucchiara et al., GCN 13217.
We are grateful for the excellent support from the Paranal Observatory staff, in particular Claudio Melo. We are in debt to Cristiano Guidorzi for providing us a FTN finding chart.
GCN Circular #13228
P. J. Tristram (MJUO), A. Fukui (NAOJ/OAO) and T. Sako (Nagoya U.) report on behalf of the MOA collaboration.
We began prompt observations for the afterglow of GRB120404A (Stratta et al., GCN 13208) at Apr. 4 12:55:44 UT (4.7 min after the Swift trigger 519380), using the 61-cm B&C telescope at Mt John University Observatory in New Zealand. We obtained a series of I and V band images with 60 sec exposure times, followed by some 120 and 180 sec exposures, until 18:04 UT (5.2 hours after the trigger).
In the first images, we detected marginal objects having I ~ 18.6 and V ~ 19.0 at the reported coordinate of the afterglow (Osborne et al., GCN13218). The afterglow was then getting bright, as reported by Breeveld et al. (GCN 13226), reaching I = 16.6 and V = 17.4 at around 13:40 UT (about 50 min after the trigger). After the peak, the afterglow had faded out with the rate of +0.7 mag/hour. The characteristic magnitudes are summarized as bellow.
```
  UT              I                        V
-------------------------------------------------------
12:56   18.6 +2/-0.6      19.0 +1.2/-0.6
13:40   16.6 +/- 0.1        17.4 +/- 0.1
16.50   18.4 +0.6/-0.4    19.5 +0.6/-0.4
-------------------------------------------------------
```
All the above magnitudes are measured on 60-sec exposure images, and calibrated by the GSC2.3 star catalog. The errors represent 1-sigma statistic uncertainties.
We would like to thank Alberto J Castro-Tirado for giving us useful suggestions. We acknowledge University of Canterbury for allowing the use of the B&C telescope.
GCN Circular #13229
V. Sudilovsky, A. Rau , J. Greiner (all MPE Garching), report on behalf of the GROND team:
We observed the field of GRB120404A (Swift trigger 519380; Stratta et al., GCN #13208) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG/ESO telescope at La Silla Observatory (Chile). Observations started at 2012-04-05 07:01:16 UT, 18.2 hours after the GRB trigger.
The afterglow (e.g., Stratta et al., GCN #13208; Guidorzi et al., GCN #13209) is clearly detected. At mid-time of 19.3 hours post trigger and with an exposure of 20 min we measure the following preliminary SDSS (g'r'i'z') and 2MASS (JHK) calibrated AB magnitudes:
```
g' = 23.2 +- 0.3
r' = 22.6 +- 0.1
i' = 22.3 +- 0.1
z' = 22.0 +- 0.1
J = 21.2 +- 0.3
H = 20.6 +- 0.3
K > 20.0
```
The SED, corrected for the Galactic foreground reddening of E_(B-V)=0.05 mag (Schlegel et al. 1998) is best fit by a power law with a slope of beta~1.4 and no additional rest frame extinction.
The comparison with the MITSuME observation at 4.8 hours post-trigger (Kuroda et al., GCN #13224) and TNT measurement at 7.4 hours post-trigger (Xin et al., GCN #13221) suggests a significant steepening of the afterglow decay. Assuming the decay started around ~7.4 hours post-trigger, we estimate the decay slope to be ~2.2.
GCN Circular #13230
E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, A.Belinski, N.Tyurina, N.Shatskiy, P.Balanutsa, D.Zimnukhov, A.Kuznetsov, V.V.Chazov, A.Kuznetsov,A.Sankovich Moscow Lomonosov State University, Sternberg Astronomical Institute,
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
V.Krushinski, I.Zalozhnich, A. Popov, A. Bourdanov, A. Punanova Ural Federal University
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)
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Blagoveschensk was pointed to the GRB120404A 24 sec after notice time and 71 sec after GRB time at 2012-04-04 12:52:13.917 UT (Yurkov et al., GCN 13210).
The observations was made with a full moon and at high zenith distance. We see an OT (G. Stratta et. al., GCN 13208) on 3 single and some coadd images. First time the OT seen at coadd of six first images set with magnitude about 16.8. After this time the object was decay below 17.5 mag for an hour. The OT have a flash to 16.9 mag in our unfiltered band (0.8R+0.2B) ~ 1 h after trigger time.
The detail imformation about observations in a table 1.
Table 1.
```
T_mid UT | T-T_grb sec.| Exptime | Coadd  |  Mag | err.mag
---------+-------------+---------+--------+------+--------
12:55:25 |  263        |  180    |  6     | 16.8 |  0.3
13:46:14 | 3311        |  180    |  1     | 17.2 |  0.4
13:49:40 | 3517        |  180    |  1     | 16.9 |  0.4
13:56:33 | 3930        |  180    |  1     | 17.1 |  0.4
14:10:22 | 4760        |  900    |  5     | 17.8 |  0.3
14:36:13 | 6311        | 1800    | 10     | 18.1 |  0.3
15:21:03 | 9001        | 1800    | 10     | 18.2 |  0.3
----------------------------------------------------------
```
The message may be cited.
GCN Circular #13231
Ashley Zauderer, Tanmoy Laskar and Edo Berger (Harvard) report:
"We observed the position of GRB 120404A (GCN 13208) with the EVLA at 22 GHz beginning 2012 Apr 5.27 UT (0.75 d after the burst). We detect a source at 22 GHz consistent with the Swift-XRT (GCN 13218) and the UVOT position (GCN 13208) with a flux of 82 uJy (+/- 22 uJy). The position of the radio source is
```
RA    15:40:02.28 (+/- 0.01)
DEC  +12:53:06.1  (+/- 0.1)
```
The source was not detected at 6 GHz (3-sigma upper limit of 33 uJy)."
GCN Circular #13232
B. E. Cobb (GWU) reports:
Using the ANDICAM instrument on the 1.3m telescope at CTIO, we obtained optical/IR imaging of the error region of GRB 120404A (GCN 13208, Stratta et al.) with a mid-exposure time of 17.4 hours post-burst (2012-04-05 06:13 UT). Total summed exposure times amounted to 36 minutes in I and 30 minutes in J.
No source is detected at the position of the optical afterglow (e.g. GCN 13208, Stratta et al.; GCN 13209, Guidorzi et al.) to approximate limiting magnitudes of I > 21.6 and J > 19.6. Magnitudes are calibrated using USNO-B1.0 stars in I, and 2MASS stars in J.
GCN Circular #13233
I.A. Smith (Rice U.), R.P.J. Tilanus (JAC), N.R. Tanvir (U. of Leicester), D.A. Frail (NRAO) report:
We observed the counterpart to GRB 120404A (Stratta et al., GCN Circ. 13208) using the SCUBA-2 sub-millimeter continuum camera on the James Clerk Maxwell Telescope. The observation started at 13:50 UT on 2012-04-04, corresponding to 59 minutes after the burst trigger. Exposures totaling one hour were made in marginal weather conditions. No source was detected, with a preliminary RMS of 4.1 mJy at 850 microns.
We thank William Montgomerie for his prompt support of these observations.
GCN Circular #13234
Brajesh Kumar, Vijay Kumar Bhatt and S.B. Pandey (ARIES, Nainital, India, on behalf of larger Indian GRB collaboration)
We started to observe the GRB 120404A field (Swift trigger 519380, Stratta et al., GCN Circ. 13208) with the 1.04m telescope at ARIES, Nainital starting 2012-04-04 19:18:43 (UT). Several images in R_c and I_c pass-bands were obtained.
The optical afterglow candidate (Stratta et al., GCN Circ. 13208, Guidorzi et al. GCN Circ. 13209) was clearly detected in our frames. The preliminary photometry of co-added R_c (300sec x 4) and I_c (300sec x 3) frames yield the following magnitudes.
```
...............................................................
Time (MID-UT)     Exp (sec)          Filter        Magnitude
...............................................................
19:39:40           1200                R_c       20.6 +/- 0.14
19:51:22            900                I_c       19.7 +/- 0.12
...............................................................
```
The nearby USNO stars have been used for calibration.
This massage may be cited.
GCN Circular #13235
A. Volnova (SAI MSU), D. Varda (ISON), E. Sinyakov (ISON), E. Litvinenko (UBAI), V. Kouprianov (GAO), I. Molotov (KIAM), A. Pozanenko (IKI) on behalf of larger GRB follow up collaboration report:
We observed the field of the Swift GRB 120404A (Stratta et al., GCN 13208) with ORI-25 (0.25-m) telescope of ISON-Blagoveschensk observatory between Apr. 04 (UT) 13:06:10 - 14:43:45 and ORI-40 (0.4-m) telescope of ISON-Kitab observatory between Apr. 04 (UT) 17:13:02 - 18:16:58. Several unfiltered images were taken in both observatories. We detected optical afterglow (Stratta et al., GCN 13208; Guidorzi et al., GCN 13209) in combined image (see below). Coordinates of the OT are (J2000) 15:40:02.17, +12:53:06.5 with unceraininty of 0.75" on both coordinates which is compatible with coordinates reported by UVOT team (Stratta et al., GCN 13208). A photometry is based on nearby USNO-B1.0 stars (R2 magnitude):
```
t_start,    t-t0 (mid),  filter  exp.,    OT,                UL
(UT)             d                   s

13:06:10 0.01529  none  12x25   n/d                   16.5
13:21:11 0.03700  none  38x25   17.35 +/- 0.25 17.5
14:08:43 0.06611  none  29x25   n/d                   17.9
17:13:02 0.20378  none  60x60   n/d                   18.9
```
Based on initially non-detection of the OT we can confirm the brightening of the afterglow (Breeveld et al., GCN 13226; Tristram et al., GCN 13228; Gorbovskoy et al., GCN 13230) with a peak between (UT) 13:21 and 14:06 (i.e. ~ 50 min after burst trigger).
GCN Circular #13236
A.Volnova (SAI MSU), E. Klunko (ISTP), A. Pozanenko (IKI) on behalf of larger GRB follow up collaboration report:
We observed the field of the Swift GRB 120404A (Stratta et al., GCN 13208) with AZT-33IK telescope of Sayan observatory (Mondy). We took several images in R-filter of 60 s exposure on Apr. 04, starting (UT) 14:31:21. We clearly detected optical afterglow (Stratta et al., GCN 13208; Guidorzi et al., GCN 13209) in single images. A preliminary photometry of combined images is based on nearby USNO-B1.0 stars:
```
t_start,    t-t0 (mid),  filter exp., OT,    err
(UT)             d               s
 14:31:21     0.07142 R 5x60   18.24  0.05
 14:37:26     0.07564 R 5x60   18.36  0.04
 14:42:30     0.07916 R 5x60   18.40  0.05
 14:47:34     0.08268 R 5x60   18.36  0.07
 14:52:37     0.08619 R 5x60   18.59  0.07
 14:58:42     0.09041 R 5x60   18.59  0.04
 15:03:46     0.09393 R 5x60   18.77  0.12
 15:08:50     0.09920 R 10x60 18.76  0.06
 15:19:58     0.10694 R 10x60 18.95  0.06
 15:30:06     0.11432 R 10x60 18.94  0.08
 15:41:14     0.12171 R 10x60 19.00  0.08
 15:51:21     0.12908 R 10x60 19.30  0.09
```
Our photometry suggests bumpy light curve of the afterglow during our observations.
GCN Report 372.1
GCN_Report 372.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_372_1.pdf by G. Stratta at ASDC titled: "Final Swift Observations of GRB 120404A"
1311.4340 from 19 Nov 13
C. Guidorzi et al.: New constraints on GRB jet geometry and relativistic shock physics
We use high--quality, multi-band observations of Swift GRB120404A, from gamma-ray to radio frequencies, together with the new hydrodynamics code of van Eerten et al. (2012) to test the standard synchrotron shock model. The evolution of the radio and optical afterglow, with its prominent optical rebrightening at t_rest 260-2600 s, is remarkably well modelled by a decelerating jet viewed close to the jet edge, combined with some early re-energization of the shock. We thus constrain the geometry of the jet with half-opening and viewing angles of 23 and 21 deg respectively and suggest that wide jets viewed off-axis are more common in GRBs than previously thought. We also derive the fireball microphysics parameters epsilon_B=2.4e-4 and epsilon_e=9.3e-2 and a circumburst density of n=240 cm^-3. The ability to self-consistently model the microphysics parameters and jet geometry in this way offers an alternative to trying to identify elusive canonical jet breaks at late times. The mismatch between the observed and model-predicted X-ray fluxes is explained by the local rather than the global cooling approximation in the synchrotron radiation model, constraining the microphysics of particle acceleration taking place in a relativistic shock and, in turn, emphasising the need for a more realistic treatment of cooling in future developments of theoretical models. Finally, our interpretation of the optical peak as due to the passage of the forward shock synchrotron frequency highlights the importance of high quality multi-band data to prevent some optical peaks from being erroneously attributed to the onset of fireball deceleration.

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Jochen Greiner, last update: 19-Nov-2013 [Disclaimer]