Gamma-ray Burst 070412

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 12 Apr 07 01:38:16 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     275119,   Seg_Num: 0
GRB_RA:          181.505d {+12h 06m 01s} (J2000),
                 181.597d {+12h 06m 23s} (current),
                 180.869d {+12h 03m 29s} (1950)
GRB_DEC:         +40.101d {+40d 06' 03"} (J2000),
                 +40.060d {+40d 03' 37"} (current),
                 +40.379d {+40d 22' 45"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       3250 [cnts]    Image_Peak=150 [image_cnts]
TRIGGER_DUR:     0.512 [sec] 
TRIGGER_INDEX:   124     E_range: 25-100 keV
BKG_INTEN:       43100 [cnts]
BKG_TIME:        5206.11 SOD {01:26:46.11} UT
BKG_DUR:         8 [sec]
GRB_DATE:        14202 TJD;   102 DOY;   07/04/12
GRB_TIME:        5223.39 SOD {01:27:03.39} UT
GRB_PHI:         -65.96 [deg]
GRB_THETA:        10.54 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     8.94 [sigma]
IMAGE_SIGNIF:    7.32 [sigma]
MERIT_PARAMS:     +1  +0  +0  -1  +2  +0  +0  +0 +62  +1 
SUN_POSTN:        20.14d {+01h 20m 33s}   +8.49d {+08d 29' 16"}
SUN_DIST:        128.51 [deg]   Sun_angle= -10.8 [hr] (East of Sun)
MOON_POSTN:      311.18d {+20h 44m 43s}  -21.26d {-21d 15' 50"}
MOON_DIST:       133.46 [deg]
MOON_ILLUM:      36 [%]
GAL_COORDS:      156.00, 73.98 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      162.73, 36.80 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This Notice was delayed by more than 60 sec past the end of the trigger integration interval;  
COMMENTS:        probably due to it occurring during a Malindi downlink session.  
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 = 14.23,-13.71 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 12 Apr 07 01:38:47 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     275119,   Seg_Num: 0
GRB_RA:          181.5422d {+12h 06m 10.1s} (J2000),
                 181.6345d {+12h 06m 32.2s} (current),
                 180.9067d {+12h 03m 37.6s} (1950)
GRB_DEC:         +40.1425d {+40d 08' 32.9"} (J2000),
                 +40.1020d {+40d 06' 07.2"} (current),
                 +40.4208d {+40d 25' 15.0"} (1950)
GRB_ERROR:       5.8 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       24 [cnts]
IMG_START_DATE:  14202 TJD;   102 DOY;   07/04/12
IMG_START_TIME:  5284.61 SOD {01:28:04.61} UT,   61.2 [sec] since BAT Trigger Time
CENTROID_X:      232.03,  raw= 232  [pixels]
CENTROID_Y:      251.05,  raw= 251  [pixels]
ROLL:            336.22 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -110.65
GRB_POS_XRT_Z:   -165.63
IMAGE_URL:       sw00275119000msxps_rw.img
SUN_POSTN:        20.14d {+01h 20m 33s}   +8.49d {+08d 29' 16"}
SUN_DIST:        128.49 [deg]   Sun_angle= -10.8 [hr] (East of Sun)
MOON_POSTN:      311.18d {+20h 44m 44s}  -21.26d {-21d 15' 44"}
MOON_DIST:       133.43 [deg]
MOON_ILLUM:      36 [%]
GAL_COORDS:      155.82, 73.96 [deg] galactic lon,lat of the burst
ECL_COORDS:      162.73, 36.85 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 12 Apr 07 01:38:47 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     275119,   Seg_Num: 0
GRB_RA:          181.5422d {+12h 06m 10.1s} (J2000),
                 181.6345d {+12h 06m 32.2s} (current),
                 180.9067d {+12h 03m 37.6s} (1950)
GRB_DEC:         +40.1425d {+40d 08' 32.9"} (J2000),
                 +40.1020d {+40d 06' 07.2"} (current),
                 +40.4208d {+40d 25' 15.0"} (1950)
GRB_ERROR:       5.8 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       7.03e-10 [erg/cm2/sec]
GRB_SIGNIF:      4.89 [sigma]
IMG_START_DATE:  14202 TJD;   102 DOY;   07/04/12
IMG_START_TIME:  5284.61 SOD {01:28:04.61} UT,   61.2 [sec] since BAT Trigger Time
TAM[0-3]:        327.64 237.18 261.29 243.55
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:        20.14d {+01h 20m 33s}   +8.49d {+08d 29' 16"}
SUN_DIST:        128.49 [deg]   Sun_angle= -10.8 [hr] (East of Sun)
MOON_POSTN:      311.18d {+20h 44m 44s}  -21.26d {-21d 15' 44"}
MOON_DIST:       133.43 [deg]
MOON_ILLUM:      36 [%]
GAL_COORDS:      155.82, 73.96 [deg] galactic lon,lat of the burst
ECL_COORDS:      162.73, 36.85 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 12 Apr 07 01:38:52 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     275119,   Seg_Num: 0
GRB_RA:          181.5422d {+12h 06m 10.1s} (J2000),
                 181.6345d {+12h 06m 32.2s} (current),
                 180.9067d {+12h 03m 37.6s} (1950)
GRB_DEC:         +40.1425d {+40d 08' 32.9"} (J2000),
                 +40.1020d {+40d 06' 07.2"} (current),
                 +40.4208d {+40d 25' 15.0"} (1950)
GRB_ERROR:       5.8 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       24 [cnts]
IMG_START_DATE:  14202 TJD;   102 DOY;   07/04/12
IMG_START_TIME:  5284.61 SOD {01:28:04.61} UT,   61.2 [sec] since BAT Trigger Time
CENTROID_X:      232.03,  raw= 232  [pixels]
CENTROID_Y:      251.05,  raw= 251  [pixels]
ROLL:            336.22 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -110.65
GRB_POS_XRT_Z:   -165.63
IMAGE_URL:       sw00275119000msxps_rw.img
SUN_POSTN:        20.14d {+01h 20m 33s}   +8.49d {+08d 29' 16"}
SUN_DIST:        128.49 [deg]   Sun_angle= -10.8 [hr] (East of Sun)
MOON_POSTN:      311.18d {+20h 44m 44s}  -21.26d {-21d 15' 43"}
MOON_DIST:       133.43 [deg]
MOON_ILLUM:      36 [%]
GAL_COORDS:      155.82, 73.96 [deg] galactic lon,lat of the burst
ECL_COORDS:      162.73, 36.85 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 12 Apr 07 01:39:57 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     275119,   Seg_Num: 0
POINT_RA:        181.530d {+12h 06m 07s} (J2000)
POINT_DEC:       +40.089d {+40d 05' 19"} (J2000)
POINT_ROLL:      336.222d
IMG_START_DATE:  14202 TJD;   102 DOY;   07/04/12
IMG_START_TIME:  5293.03 SOD {01:28:13.03} UT,   69.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        0.712
N_STARS:         15
X_OFFSET:        568 [pixels]
Y_OFFSET:        416 [pixels]
X_MAX:           1527 [pixels]
Y_MAX:           1375 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw00275119000msufc0069.fits
SUN_POSTN:        20.14d {+01h 20m 33s}   +8.49d {+08d 29' 17"}
SUN_DIST:        128.53 [deg]   Sun_angle= -10.8 [hr] (East of Sun)
MOON_POSTN:      311.20d {+20h 44m 47s}  -21.26d {-21d 15' 31"}
MOON_DIST:       133.46 [deg]
MOON_ILLUM:      36 [%]
GAL_COORDS:      155.97, 74.00 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      162.75, 36.80 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 12 Apr 07 01:40:22 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     275119,   Seg_Num: 0
POINT_RA:        181.530d {+12h 06m 07s} (J2000)
POINT_DEC:       +40.089d {+40d 05' 19"} (J2000)
ROLL:            336.222d
IMG_START_DATE:  14202 TJD;   102 DOY;   07/04/12
IMG_START_TIME:  5293.03 SOD {01:28:13.03} UT,   69.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     198034094
X_OFFSET:        1201 [pixels]
Y_OFFSET:        909 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1361
Y_GRB_POS:       1069
BINNING_INDEX:   1
IM_URL:          sw00275119000msuni0069.fits
SUN_POSTN:        20.14d {+01h 20m 33s}   +8.49d {+08d 29' 18"}
SUN_DIST:        128.53 [deg]   Sun_angle= -10.8 [hr] (East of Sun)
MOON_POSTN:      311.20d {+20h 44m 48s}  -21.26d {-21d 15' 26"}
MOON_DIST:       133.46 [deg]
MOON_ILLUM:      36 [%]
GAL_COORDS:      155.97, 74.00 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      162.75, 36.80 [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:     Thu 12 Apr 07 01:40:26 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     275119,   Seg_Num: 0
POINT_RA:        181.530d {+12h 06m 07s} (J2000)
POINT_DEC:       +40.089d {+40d 05' 19"} (J2000)
POINT_ROLL:      336.222d
IMG_START_DATE:  14202 TJD;   102 DOY;   07/04/12
IMG_START_TIME:  5293.03 SOD {01:28:13.03} UT,   69.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        0.712
N_STARS:         15
X_OFFSET:        568 [pixels]
Y_OFFSET:        416 [pixels]
X_MAX:           1527 [pixels]
Y_MAX:           1375 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw00275119000msufc0069.fits
SUN_POSTN:        20.14d {+01h 20m 33s}   +8.49d {+08d 29' 18"}
SUN_DIST:        128.53 [deg]   Sun_angle= -10.8 [hr] (East of Sun)
MOON_POSTN:      311.20d {+20h 44m 48s}  -21.26d {-21d 15' 25"}
MOON_DIST:       133.46 [deg]
MOON_ILLUM:      36 [%]
GAL_COORDS:      155.97, 74.00 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      162.75, 36.80 [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:     Thu 12 Apr 07 01:40:48 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     275119,   Seg_Num: 0
GRB_RA:          181.505d {+12h 06m 01s} (J2000),
                 181.597d {+12h 06m 23s} (current),
                 180.869d {+12h 03m 29s} (1950)
GRB_DEC:         +40.101d {+40d 06' 03"} (J2000),
                 +40.060d {+40d 03' 37"} (current),
                 +40.379d {+40d 22' 45"} (1950)
GRB_DATE:        14202 TJD;   102 DOY;   07/04/12
GRB_TIME:        5223.39 SOD {01:27:03.39} UT
TRIGGER_INDEX:   124
GRB_PHI:         -65.96 [deg]
GRB_THETA:        10.54 [deg]
DELTA_TIME:      32.00 [sec]
TRIGGER_DUR:     0.512 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     8.94 [sigma]
IMAGE_SIGNIF:    7.32 [sigma]
LC_URL:          sw00275119000msb.lc
SUN_POSTN:        20.14d {+01h 20m 33s}   +8.49d {+08d 29' 18"}
SUN_DIST:        128.51 [deg]   Sun_angle= -10.8 [hr] (East of Sun)
MOON_POSTN:      311.20d {+20h 44m 49s}  -21.26d {-21d 15' 21"}
MOON_DIST:       133.48 [deg]
MOON_ILLUM:      36 [%]
GAL_COORDS:      156.00, 73.98 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      162.73, 36.80 [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 = 14.23,-13.71 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 12 Apr 07 01:40:07 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     275119,   Seg_Num: 0
POINT_RA:        181.530d {+12h 06m 07s} (J2000)
POINT_DEC:       +40.089d {+40d 05' 19"} (J2000)
ROLL:            336.222d
IMG_START_DATE:  14202 TJD;   102 DOY;   07/04/12
IMG_START_TIME:  5293.03 SOD {01:28:13.03} UT,   69.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     198034094
X_OFFSET:        1201 [pixels]
Y_OFFSET:        909 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1361
Y_GRB_POS:       1069
BINNING_INDEX:   1
IM_URL:          sw00275119000msuni0069.fits
SUN_POSTN:        20.14d {+01h 20m 33s}   +8.49d {+08d 29' 17"}
SUN_DIST:        128.53 [deg]   Sun_angle= -10.8 [hr] (East of Sun)
MOON_POSTN:      311.20d {+20h 44m 47s}  -21.26d {-21d 15' 29"}
MOON_DIST:       133.46 [deg]
MOON_ILLUM:      36 [%]
GAL_COORDS:      155.97, 74.00 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      162.75, 36.80 [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 Circular #6273
P. Romano (Univ. Bicocca & INAF-OAB), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC), S. T. Holland (CRESST/GSFC/USRA), H. A. Krimm (GSFC/USRA), A. Moretti (INAF-OAB), C. Pagani (PSU), D. M. Palmer (LANL), T. Sakamoto (NASA/ORAU), M. Stamatikos (NASA/ORAU) and D. E. Vanden Berk (PSU) report on behalf of the Swift Team:
At 01:27:03 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 070412 (trigger=275119). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 181.505, +40.101 which is
```
   RA(J2000) = 12h 06m 01s
   Dec(J2000) = +40d 06' 03"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a double-peaked structure with peaks at approximately 5 and 30 seconds and a total duration of about 40 sec. The peak count rate was ~2400 counts/sec (15-350 keV), at ~5 sec after the trigger.
The XRT began observing the field at 01:28:04 UT, 61 seconds after the BAT trigger. Analysis of XRT downlinked data found an X-ray source located at RA, Dec 181.54, +40.141 which is
```
   RA(J2000)  =  12h 06m 10.5s  
   Dec(J2000) =  40d 08' 27.8"
```
with an uncertainty of 5.6 arcseconds (radius, 90% containment). This location is 181 arcseconds from the BAT on-board position, outside the BAT error circle. The initial flux in the 2.5s image was 7.0e-10 erg/cm2/s (0.2-10 keV).
UVOT took a finding chart exposure of 54 seconds with the White (160-650 nm) filter starting 70 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. Image catalog data are not available at this time. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the extinction of E(B-V)=0.02.
The TDRSS transmissions were delayed by 11 minutes due to the trigger occuring during a Malindi downlink.
GCN Circular #6275
E. O. Ofek (Caltech) and E. Berger (Carnegie) reports on behalf of a larger collaboration:
The XRT error circle of GRB 070412 (Romano et al. 2007; GCN 6273), coincides with the outskirts of a nearby (z=0.037) bright (r=13.6) galaxy (CGCG 215-024).
The XRT position is 46.5" from the galaxy center (34 kpc projected).
The SDSS coordinates of the galaxy are:
```
 	RA = 12:06:07.818
 	DEC= +40:09:02.68 (J2000)
```
GCN Circular #6276
D. Malesani (DARK/NBI) and H. Uthars (NOT) report:
We observed the field of GRB 070412 (Romano et al., GCN 6273) using the NOT + ALFOSC in the R and i bands. Inside the XRT error circle, we detect a source at the detection limit (R = 24 +- 0.3) at the following coordinates:
```
alpha = 12:06:10.83
delta = 40:08:27.8
```
The source is only detected in the (deeper) R-band frame. No other source is deteted inside the XRT error circle fown to R~24.1. The observation was carried out 56 min after the trigger.
Given the large size of the error box (5.6"), we cannot assess whether this source is associated to the GRB. We note however the lack of bright objects inside the XRT circle.
Further observations are underway.
GCN Circular #6279
M. Jelinek (IAA-CSIC, Granada). J. A. Caballero (MPIA Heidelberg), A. de la Nuez (IAC La Laguna) and A. J. Castro-Tirado (IAA-CSIC), on behalf of larger colaboration.
report:
"We have observed the field of GRB070412 (Romano et al. GCNC 6273) with the IAC80 telescope at Observatorio del Teide in I filter, starting at 03:02 UT, i.e. 1.6 h after the trigger.
Inspection of a 30 minute combined image shows a faint (4-sigma) source at
12:06:10.416,+40:08:24.12 +-0.5" (J2000)
with the I-band brightness 21.5+-0.5. The object is not consistent with the candidate of Malesani et al. (GCN 6276). The identification map is at
http://www.iaa.es/~mates/grb070412id.jpg
Further observations are needed to confirm the transient nature of this object.
GCN Circular #6280
E. Begrer (Carnegie) reports on behalf of a larger collaboration:
"We observed the XRT error circle of GRB 070412 (GCN 6273) with GMOS on the Gemini-north telescope for a total of 360 sec in i-band starting on 2007 Apr 12.229 UT (4 hr after the burst). Within the XRT error circle we find a single faint object with i=23.9+/-0.2 mag (using the zeropoint on the GMOS website) located at:
```
 	RA = 12:06:10.585
 	DEC = +40:08:24.83  (J2000)
```
with an uncertainty of about 0.2". This position is 3.2" away from the center of the XRT error circle (GCN 6273) and 2.1" away from the I-band source discussed in GCN 6279. The non-detection of an object at this position in the R-band to a limit of 24 mag at t=1 hr (GCN 6276) indicates that this object (if it is the afterglow) is red, with R-I ~ 1.6 mag for a fading rate of t^-1."
GCN Circular #6281
Daniele Malesani (DARK/NBI) and Helene Uthas (NOT) report on behalf of a larger collaboration:
We observed again the field of GRB 070412 (Romano et al., GCN 6273) with the NOT. Observations were carried out at two epochs, ~0.9 and ~3.5 hr after the GRB. R- and I-band images were secured at each epoch.
Inside the XRT error circle, we do not detect the sources reported by Jelinek et al. (GCN 6279) and Berger (GCN 6280). The 3-sigma limiting magnitudes are:
```
t-t0     I limit   R limit
--------------------------
0.9 hr   22.9      24.0
3.5 hr   23.1      24.2
```
These numbers were computed assuming R = 17.38 and I = 17.17 for the USNO star at RA = 12:06:02.17, Dec = +40:09:01.4. We note that the magnitude reported by Berger (GCN 6280) is fainter than our limits. Our early measurement implies a decay shallower than ~t^-0.7.
The object reported by Malesani & Uthas (GCN 6276) is detected only in the first R-band image, thus leaving open the possibility that this source was fading. However, we caution about the low significance of this detection.
GCN Circular #6282
P. Romano, C. Guidorzi (Univ. Bicocca & INAF-OAB), A. Moretti (INAF-OAB), P.A.Evans (LU) report on behalf of the Swift Team:
We have analysed the first 4 orbits of XRT data from GRB 070412 (Romano et al., GCN Circ. 6273). A 2.4ks photon counting mode image provides a refined XRT position RA,Dec=181.5426 +40.1438 :
```
RA(J2000)  =12h 06m 10.22s
Dec(J2000) =+40d 08' 37.8"
```
with an uncertainty of 4 arcsec (90% containment). This is 10.5 arcsec away from the initial XRT position quoted in GCN Circ. 6273 (Romano et al.). Based on these new coordinates, the position of the NOT candidate (Malesani et al., GCN Circ.6276), the IAC80 optical candidate (M. Jelinek et al., GCN Circ. 6279), as well as the position of the i-band candidate afterglow (Berger et al., GCN Circ 6280), are all outside our error circle.
This circular is an official product of the Swift XRT Team.
GCN Circular #6284
H. Mikuz, J. Skvarc and B. Dintinjana on behalf of PIKA observing program at Crni Vrh Observatory:
We observed a 42'x42' field centered on Swift position at ra=12:06:01 dec=+40:06:03 (J2000), using 60 cm Cichocki robotic telescope at Crni Vrh Observatory, Slovenia. There is no obvious source down to R magnitude 20.7 +/-0.1 inside the error box 3x3 arc minutes on 90 s R filter exposure, starting at 2007 Apr. 12 01:39:03 UT (46 seconds after reception of the alert) and 5 subsequent images of the same duration. Magnitudes were calibrated against the USNO-B1 catalogue. In particular we also do not observe any source to this limiting magnitude at the coordinates reported by NOT (Malesani and Uthars, GCN 6276) or Jelinek et al. (GCN 6279).
GCN Circular #6285
Daniele Malesani (DARK/NBI) and Helena Uthas (NOT) report:
Following the revision of XRT error circle position (Romano et al., GCN 6282) of GRB 070412 (Romano et al., GCN 6723), we further inspected our NOT R- and I-band images (Malesani & Uthas, GCNs 6276, 6281).
No objects are detected down to the same limits presented in GCN 6281.
GCN Circular #6287
P. Romano (Univ. Bicocca & INAF-OAB), A. Moretti (INAF-OAB), C. Guidorzi (Univ. Bicocca & INAF-OAB) report on behalf of the Swift Team:
We have analysed the first 4 orbits of XRT data from GRB 070412 (trigger=275119; Romano et al., GCN Circ. 6273), which include 40s in WT and 2.4ks in PC mode. The refined XRT position is RA,Dec=181.5426 +40.1438:
```
RA(J2000)  =12h 06m 10.2s
Dec(J2000) =+40d 08' 37.8"
```
with an uncertainty of 4 arcsec (90% containment, see GCN Circ. 6282).
The 0.3-10 keV X-ray light curve can be fit with a simple power-law with a decay slope of 0.98+/-0.05, although the initial descent could be due to a flare or the tail of the prompt emission (slope of ~-3.5).
The X-ray spectrum from the XRT/WT data (40s starting from T+67.8) can be fit by an absorbed power-law with a photon index of 2.2+/-0.5 and column density of (1.8-0.9+1.1)E21 cm**-2, higher than the Galactic column density in the direction of the source (1.95E20 cm**-2). The unabsorbed (absorbed) 0.3-10 keV flux for this spectrum is 3.3E-10 (2.2E-10) erg/cm**2/s. The XRT/PC data (2.4ks starting from T+3386) can be fit by an absorbed power-law with a photon index of 2.3-0.5+0.6 and column density of (2.5-1.2+1.4)E21 cm**-2, consistently with the WT data. The unabsorbed (absorbed) 0.3-10 keV flux for this spectrum is 6.1E-12 (3.3E-12) 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 5.6E-3 count/s at T+24hr, which corresponds to an observed 0.3-10 keV flux of 2.8E-13 erg/cm**2/s.
This circular is an official product of the Swift XRT Team.
GCN Circular #6289
A. Gomboc (Univ. of Ljubljana, Slovenia), A. Melandri, R.J. Smith, C. Guidorzi, M. Burgdorf, C.G. Mundell, I.A. Steele, D. Carter, A. Monfardini, C.J. Mottram, S. Kobayashi, D. Bersier (Liverpool JMU) report:
The 2-m Liverpool Telescope started observing the field of GRB 070412 (Romano et al. GCN 6273) at 14.1 min after the trigger time.
At the revised XRT position (Romano et al. GCN 6282 and GCN 6287) we do not detect any new object in stacked images down to:
```
Filter      t_mid (min from GRB)    Tot_Exp (s)       Lim
------------------------------------------------------------------
r'             35.8                    720            22.0
i'             41.4                    720            21.3
------------------------------------------------------------------
```
Magnitudes were calibrated vs the USNOB1 catalogue.
GCN Circular #6290
T. Sakamoto (GSFC/ORAU), L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), P. Romano (Univ. Bicocca & INAF-OAB), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC) on behalf of the Swift-BAT team:
Using the data set from T-239.3 to T+962.8 sec from the recent telemetry downlink, we report further analysis of BAT GRB 070412 (trigger #275119) (Romano, et al., GCN Circ. 6273). The BAT ground-calculated position is RA, Dec = 181.525, 40.133 deg which is
```
    RA(J2000) = 12h 06m 6.1s
    Dec(J2000) = 40d 07' 57.0"
```
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 98%.
The mask-weighted light curve shows a double-peaked structure with the first peak from approximately T-4 sec to T+10 sec and a second 2-sec long peak at T+30 sec. T90 (15-350 keV) is 34 +- 2 sec (estimated error including systematics). The spacecraft slewed away from the burst location at T+122 sec, although the burst remained in the partially coded field of view until T+716 sec, when the spacecraft slewed away again.
The time-averaged spectrum from T-4.1 to T+31.2 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.45 +- 0.20. The fluence in the 15-150 keV band is 4.8 +- 0.7 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+5.32 sec in the 15-150 keV band is 0.7 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
GCN Circular #6293
P. Schady (MSSL/PSU) and P.Romano (Univ. Bicocca & INAF-OAB) report on behalf of the Swift UVOT team:
Swift/UVOT observed the field of GRB 070412 starting 97.6s after the BAT trigger. No new source is detected within the XRT refined position (GCN 6282) or at the position reported by Jelinek et al. (GCN 6279) and Berger et al. (GCN 6280) in any of the UVOT filters, in either single or co-added exposures. The 3-sigma upper limits for the co-added exposures in each filter are as follows:
```
Filter        T_mid       Exp.     Mag 3-sig UL
                     (s)           (s)
White       9252        936      20.55
V               17432     1769    20.52
B               5763        171      20.22
U               23567     1082    21.12
UVW1       23107     1284   20.52
UVM2       19141     1082   20.65
UVW2       14440     1195   20.94
```
where T_mid is the weighted mid time of the co-added images. The reported upper limits are uncorrected for the estimated Galactic reddening of E(B-V) = 0.02 mag.
GCN Report 45.1
GCN_Report 45.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_45_1.pdf by P. Romano at U.Bicacco and INAF-OAB titled: "Swift Observations of GRB 070412"
GCN Circular #6294
E. Rol, N. Tanvir (U. of Leicester), A. Levan (U. of Warwick), L. Fuhrman (JAC), report for a larger collaboration:
We observed the field of GRB070412 between 4.3 and 5.4 hours after the GRB trigger (Romano et al., GCNC 6273). At the position of the X-ray afterglow (Romano et al., GCNC 6282), we detect no source. We place the following 5-sigma limiting magnitudes at this position:
```
      J    20.7
      H    20.1
      K    19.8
```
The magnitudes are calibrated with respect to the 2MASS catalogue.
GCN Report 45.2
GCN_Report 45.2 has been posted: http://gcn.gsfc.nasa.gov/reports/report_45_2.pdf by P. Romano at U.Bicocca/INAF-OAB titled: "Final Swift Observations of GRB 070412"
GCN Circular #6353
E. Rol, N. Tanvir (U. of Leicester), R. Smith (Liverpool JMU), report for a larger collaboration:
We have observed the field of GRB070412 (Romano, GCN Circ. 6273) in r' and i' bands with the 2m Liverpool Telescope at several epochs. At the position of the X-ray afterglow (Romano, GCN Circ. 6282), we do not detect any new sources. Our photometry is calibrated relative to the SDSS (Adelman-McCarthy et al., 2007 ApJS in press), and our limiting magnitudes at the observed epochs are as follows:
```
       UT start   days post T0  exptime   filter  lim. mag
        (2007)     (mid-epoch)   (sec)            (5-sigma)

   04-12T03:13:03    0.077        600       r'      22.5
   04-12T04:07:56    0.115        600       i'      21.9
   04-12T04:31:59    0.132        600       r'      22.4

   04-12T21:33:59    0.849       1800       r'      22.6
   04-13T01:48:36    1.026       1350       i'      21.6
   04-13T03:32:13    1.098       1800       r'      23.4
   04-13T04:06:36    1.122        900       i'      20.7

   04-15T01:11:04    3.000       1800       r'      23.7
   04-15T01:50:38    3.012       1800       i'      23.2

   04-25T21:34:13    13.85       1800       r'      22.3 *
   04-25T22:08:19    13.87       1800       i'      22.2 *
```
* observations are affected by contamination from the nearby moon
Since the upper limits indicate no apparent supernova at the X-ray position, the GRB position is either a chance coincidence with the nearby bright galaxy (CGCG 215-024; see also Ofek, GCN Circ. 6275), or belongs to the newly suggested class of long-duration GRBs that show no associated supernovae (Fynbo et al. 2006, Nature 444, 1047; Della Valle et al. 2006, Nature 444, 1050; Gal-Yam et al. 2006, Nature 444, 1053). For comparison, the expected magnitudes at 13.9 days for a SN1998bw-like supernova at the redshift of the galaxy (z=0.0307), are r' = 17.3 and i' = 17.6.
GCN Circular #6374
J. Prieto (Ohio State), P. Garnavich (Notre Dame), J. Hill (LBTO/UAz), X. Fan, J. Harris, J. Bechtold (U Ariz), X. Dai, P. Martini, K. Z. Stanek (Ohio State), R. M. Wagner (LBTO/OSU), J. Rhoads (Ariz State), E. Pian (INAF) report:
The Large Binocular Telescope (LBT) imaged the position of the GRB 070412 afterglow (Romano et al, GCN 6273; Romano et al. GCN 6282) with the LBC-blue CCD camera (http//lbc.mporzio.astro.it) and 8.4-m SX mirror on 2007 April 12.18 (UT) and again on April 20.31 (UT). These are 2.8 hours and 8.2 days after the burst respectively. On the first visit, ten dithered, 200 second exposures were obtained with the Sloan-r filter in 1.7" seeing while on the second visit, five exposures were obtained in 1.0" seeing.
Image matching, PSF correction and subtraction of the two images shows no variable sources within 30" of the corrected XRT position (Romano et al. GCN 6282). We place a 3-sigma upper-limit on any optical afterglow at R>25.2 around 2.8 hours post-burst.
No new source is detected in our second epoch image (also see Rol et al. GCN 6353) and we place a similar detection upper-limit as our April 12 image. If the burst is associated with the bright elliptical galaxy near the XRT position (Ofek & Berger GCN 6275), then we find any supernova or other GRB progenitor would have an absolute magnitude fainter than -11 mag eight days after the burst.
A comparison of the two images after unsharp masking to reduce the elliptical galaxy light variations can be found at: http://www.nd.edu/~pgarnavi/grb070412/grb070412_LBT.jpg
```
The LBT is an international collaboration among institutions in the
United States, Italy and Germany. The LBT Corporation partners are:
*  The University of Arizona on behalf of the Arizona university system
*  Istituto Nazionale di Astrofisica, Italy
*  LBT Beteiligungsgesellschaft, Germany, representing the Max Planck
Society, the Astrophysical Institute Potsdam, and Heidelberg University
*  The Ohio State University
*  The Research Corporation, on behalf of The University of Notre Dame,
University of Minnesota and University of Virginia
```
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GCN Circular #6382
Galante N., Garczarczyk M., Gaug M., Scapin V., Bastieri D. and Longo F. report for the MAGIC collaboration:
The MAGIC Imaging Atmospheric Cherenkov Telescope performed a follow-up observation of the SWIFT-BAT burst GRB070412 (GCN circular 6273, Romano P. et al.). We received the delayed GCN alert at T0+647s, The data taking with MAGIC started at T0+701s, 27s after the alert income. We observed the sky positon for 124min on April 12th and for further 178min on April 13th, starting at T0+7.6x10^4s.
No evidence for VHE gamma-ray emission above the analysis threshold of 90 GeV was found in both data sets. A preliminary analysis, for the hypothesis of steady emission and assumption of a differential photon spectral index of -2.5, yields the following 95% CL differential flux upper limits (inc. 30% systematic error on the absolute flux level):
```
E(80-125 GeV)   : 1.03 x 10^(-11) erg/cm^2/s
E(125-175 GeV)  : 0.31 x 10^(-11) erg/cm^2/s
E(175-300 GeV)  : 0.75 x 10^(-11) erg/cm^2/s
E(300-1000 GeV) : 0.77 x 10^(-11) erg/cm^2/s
```
The upper limits correspond to the time period between T0+701s and T0+8181s.
We can also exclude emission of a constant flux during our observation in any 100s time bin higher than:
```
E(80-200 GeV)   : 2.2 x 10^(-9) erg/cm^2/s
E(200-1000 GeV) : 0.5 x 10^(-9) erg/cm^2/s
```
for the time period between T0+701s and T0+8181s, and:
```
E(80-200 GeV)   : 2.5 x 10^(-9) erg/cm^2/s
E(200-1000 GeV) : 0.5 x 10^(-9) erg/cm^2/s
```
for the time period between T0+7.6x10^4 s and T0+8.7x10^4 s.
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GCN Circular #6465
D. A. Perley, J. S. Bloom, R. J. Foley, and D. Kocevski (UC Berkeley) report:
On the night of 2007-04-16 (UT) we performed imaging on the field of GRB070412 (GCN 6273), the long burst located approximately 45" in projection from a nearby early-type galaxy (GCN 6275), using Keck I (/LRIS) under poor seeing conditions. We acquired a total of 113 minutes of usable exposure time in I-band and 132 minutes in V-band, with a mid-exposure time of approximately 11:27 UT, 106 hours after the BAT trigger.
Using the astrometrically-corrected XRT position [1] (RA=12:06:10.18, dec=+40:08:35.3, uncertainty=2.2"), we observe a faint source at the edge of the uncertainty region in I-band. This source is not detected in V-band. Calibrating with respect to nearby stars from SDSS, we calculate a magnitude of:
I = 24.6 +/- 0.3
The V-band limiting magnitude is V > 26.5.
We note that the same source is also apparent in LBT r' imaging from Prieto et al. (GCN 6374) in both their epochs of observation (2.8 hours and 8.2 days after the burst), suggesting the source is not transient, in which case we place an I-band limiting magnitude of I > 25.0 on any transient source in the XRT error circle. The red color is suggestive of a high-redshift potential host galaxy. The LBT r' detection would place a firm upper limit on the redshift to be z < 5.9.
Images of the field are located at:
http://lyra.berkeley.edu/~dperley/070412/070412keck.png http://lyra.berkeley.edu/~dperley/070412/070412keckzoom.png
The low-redshift galaxy has been subtracted using a Sersic model fit in the first image and a median filter in the second (zoom) image.
[1] http://astro.berkeley.edu/~nat/swift/xrt_pos.html
GCN Circular #6488
Klotz, A. (CESR-OMP), Boer M. (OHP), Atteia J.L. (LATT-OMP) report:
We imaged the field of GRB 070412 detected by SWIFT (trigger 275119) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. Analysis of this burst is late due to a technichal problem.
The observations started 676.6s after the GRB trigger (4.4s after the notice). The elevation of the field decreased from from 53 degrees above horizon and weather conditions were very good.
The date of trigger : t0 = 2007-04-12T01:27:03.744
The first image is 90.0s exposure in tracking mode: We do not detect any OT in the XRT location (Romano et al. 2007 GCNC 6273) with a limiting magnitude of: t0+676.6s to t0+766.6s : R > 18.5
We co-added a series of exposures: t0+676.6s to t0+1251.3s : R > 19.5
Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction.
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Jochen Greiner, last update: 08-Jun-2007 [Disclaimer]