Gamma-ray Burst 070411

(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 11 Apr 07 20:13:13 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     275087,   Seg_Num: 0
GRB_RA:          107.338d {+07h 09m 21s} (J2000),
                 107.432d {+07h 09m 44s} (current),
                 106.692d {+07h 06m 46s} (1950)
GRB_DEC:          +1.083d {+01d 04' 57"} (J2000),
                  +1.070d {+01d 04' 13"} (current),
                  +1.164d {+01d 09' 50"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       23416 [cnts]    Image_Peak=600 [image_cnts]
TRIGGER_DUR:     4.096 [sec] 
TRIGGER_INDEX:   298     E_range: 25-100 keV
BKG_INTEN:       207502 [cnts]
BKG_TIME:        72694.11 SOD {20:11:34.11} UT
BKG_DUR:         40 [sec]
GRB_DATE:        14201 TJD;   101 DOY;   07/04/11
GRB_TIME:        72753.31 SOD {20:12:33.31} UT
GRB_PHI:          14.18 [deg]
GRB_THETA:        29.17 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     8.00 [sigma]
IMAGE_SIGNIF:    10.52 [sigma]
MERIT_PARAMS:     +1  +0  +0  +3  +2  +0  +0  +1  -4  +1 
SUN_POSTN:        19.93d {+01h 19m 43s}   +8.40d {+08d 24' 18"}
SUN_DIST:         87.37 [deg]   Sun_angle= -5.8 [hr] (East of Sun)
MOON_POSTN:      308.05d {+20h 32m 12s}  -22.26d {-22d 15' 41"}
MOON_DIST:       150.82 [deg]
MOON_ILLUM:      39 [%]
GAL_COORDS:      214.01,  4.48 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      108.64,-21.24 [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 = 14.66,-18.07 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 11 Apr 07 20:17:49 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     7842322,   Seg_Num: 194
GRB_RA:          107.338d {+07h 09m 21s} (J2000),
                 107.432d {+07h 09m 44s} (current),
                 106.692d {+07h 06m 46s} (1950)
GRB_DEC:          +1.083d {+01d 04' 57"} (J2000),
                  +1.070d {+01d 04' 13"} (current),
                  +1.164d {+01d 09' 50"} (1950)
GRB_DATE:        14201 TJD;   101 DOY;   07/04/11
GRB_TIME:        72753.31 SOD {20:12:33.31} UT
TRIGGER_INDEX:   298
GRB_PHI:          14.18 [deg]
GRB_THETA:        29.17 [deg]
DELTA_TIME:      3341.00 [sec]
TRIGGER_DUR:     4.096 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     8.00 [sigma]
IMAGE_SIGNIF:    10.52 [sigma]
LC_URL:          sw00275087000msb.lc
SUN_POSTN:        19.93d {+01h 19m 43s}   +8.41d {+08d 24' 22"}
SUN_DIST:         87.37 [deg]   Sun_angle= -5.8 [hr] (East of Sun)
MOON_POSTN:      308.09d {+20h 32m 22s}  -22.25d {-22d 14' 52"}
MOON_DIST:       150.80 [deg]
MOON_ILLUM:      39 [%]
GAL_COORDS:      214.01,  4.48 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      108.64,-21.24 [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 = 14.66,-18.07 [deg].  
COMMENTS:        The 3rd packet (of 3) was missing in the lightcurve data stream.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 11 Apr 07 20:26:04 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     275087,   Seg_Num: 0
GRB_RA:          107.3327d {+07h 09m 19.8s} (J2000),
                 107.4266d {+07h 09m 42.3s} (current),
                 106.6870d {+07h 06m 44.8s} (1950)
GRB_DEC:          +1.0632d {+01d 03' 47.5"} (J2000),
                  +1.0511d {+01d 03' 03.9"} (current),
                  +1.1446d {+01d 08' 40.7"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       135 [cnts]
IMG_START_DATE:  14201 TJD;   101 DOY;   07/04/11
IMG_START_TIME:  72849.79 SOD {20:14:09.79} UT,   96.5 [sec] since BAT Trigger Time
CENTROID_X:      293.37,  raw= 293  [pixels]
CENTROID_Y:      322.68,  raw= 323  [pixels]
ROLL:            278.36 [deg]
GAIN:            2
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   58.18
GRB_POS_XRT_Z:   -21.02
IMAGE_URL:       sw00275087000msxps_rw.img
SUN_POSTN:        19.94d {+01h 19m 45s}   +8.41d {+08d 24' 29"}
SUN_DIST:         87.36 [deg]   Sun_angle= -5.8 [hr] (East of Sun)
MOON_POSTN:      308.17d {+20h 32m 42s}  -22.22d {-22d 13' 24"}
MOON_DIST:       150.75 [deg]
MOON_ILLUM:      39 [%]
GAL_COORDS:      214.03,  4.47 [deg] galactic lon,lat of the burst
ECL_COORDS:      108.64,-21.26 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 11 Apr 07 20:26:07 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     275087,   Seg_Num: 0
GRB_RA:          107.3327d {+07h 09m 19.8s} (J2000),
                 107.4266d {+07h 09m 42.3s} (current),
                 106.6870d {+07h 06m 44.8s} (1950)
GRB_DEC:          +1.0632d {+01d 03' 47.5"} (J2000),
                  +1.0511d {+01d 03' 03.9"} (current),
                  +1.1446d {+01d 08' 40.7"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       135 [cnts]
IMG_START_DATE:  14201 TJD;   101 DOY;   07/04/11
IMG_START_TIME:  72849.79 SOD {20:14:09.79} UT,   96.5 [sec] since BAT Trigger Time
CENTROID_X:      293.37,  raw= 293  [pixels]
CENTROID_Y:      322.68,  raw= 323  [pixels]
ROLL:            278.36 [deg]
GAIN:            2
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   58.18
GRB_POS_XRT_Z:   -21.02
IMAGE_URL:       sw00275087000msxps_rw.img
SUN_POSTN:        19.94d {+01h 19m 45s}   +8.41d {+08d 24' 30"}
SUN_DIST:         87.36 [deg]   Sun_angle= -5.8 [hr] (East of Sun)
MOON_POSTN:      308.17d {+20h 32m 42s}  -22.22d {-22d 13' 23"}
MOON_DIST:       150.75 [deg]
MOON_ILLUM:      39 [%]
GAL_COORDS:      214.03,  4.47 [deg] galactic lon,lat of the burst
ECL_COORDS:      108.64,-21.26 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 11 Apr 07 20:26:47 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     275087,   Seg_Num: 0
POINT_RA:        107.340d {+07h 09m 22s} (J2000)
POINT_DEC:        +1.077d {+01d 04' 35"} (J2000)
POINT_ROLL:      278.363d
IMG_START_DATE:  14201 TJD;   101 DOY;   07/04/11
IMG_START_TIME:  72996.19 SOD {20:16:36.19} UT,   242.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.194
N_STARS:         190
X_OFFSET:        517 [pixels]
Y_OFFSET:        578 [pixels]
X_MAX:           1476 [pixels]
Y_MAX:           1537 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00275087000msufc0242.fits
SUN_POSTN:        19.94d {+01h 19m 45s}   +8.41d {+08d 24' 30"}
SUN_DIST:         87.37 [deg]   Sun_angle= -5.8 [hr] (East of Sun)
MOON_POSTN:      308.18d {+20h 32m 43s}  -22.22d {-22d 13' 16"}
MOON_DIST:       150.76 [deg]
MOON_ILLUM:      39 [%]
GAL_COORDS:      214.02,  4.48 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      108.65,-21.25 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 11 Apr 07 20:26:03 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     275087,   Seg_Num: 0
GRB_RA:          107.3327d {+07h 09m 19.8s} (J2000),
                 107.4266d {+07h 09m 42.3s} (current),
                 106.6870d {+07h 06m 44.8s} (1950)
GRB_DEC:          +1.0632d {+01d 03' 47.5"} (J2000),
                  +1.0511d {+01d 03' 03.9"} (current),
                  +1.1446d {+01d 08' 40.7"} (1950)
GRB_ERROR:       4.7 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       5.10e-09 [erg/cm2/sec]
GRB_SIGNIF:      11.61 [sigma]
IMG_START_DATE:  14201 TJD;   101 DOY;   07/04/11
IMG_START_TIME:  72849.79 SOD {20:14:09.79} UT,   96.5 [sec] since BAT Trigger Time
TAM[0-3]:        327.64 237.18 261.42 243.40
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:        19.94d {+01h 19m 45s}   +8.41d {+08d 24' 29"}
SUN_DIST:         87.36 [deg]   Sun_angle= -5.8 [hr] (East of Sun)
MOON_POSTN:      308.17d {+20h 32m 41s}  -22.22d {-22d 13' 24"}
MOON_DIST:       150.75 [deg]
MOON_ILLUM:      39 [%]
GAL_COORDS:      214.03,  4.47 [deg] galactic lon,lat of the burst
ECL_COORDS:      108.64,-21.26 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact; see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 11 Apr 07 20:27:17 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     275087,   Seg_Num: 0
POINT_RA:        107.340d {+07h 09m 22s} (J2000)
POINT_DEC:        +1.077d {+01d 04' 35"} (J2000)
POINT_ROLL:      278.363d
IMG_START_DATE:  14201 TJD;   101 DOY;   07/04/11
IMG_START_TIME:  72996.19 SOD {20:16:36.19} UT,   242.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.194
N_STARS:         190
X_OFFSET:        517 [pixels]
Y_OFFSET:        578 [pixels]
X_MAX:           1476 [pixels]
Y_MAX:           1537 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00275087000msufc0242.fits
SUN_POSTN:        19.94d {+01h 19m 45s}   +8.41d {+08d 24' 31"}
SUN_DIST:         87.37 [deg]   Sun_angle= -5.8 [hr] (East of Sun)
MOON_POSTN:      308.18d {+20h 32m 44s}  -22.22d {-22d 13' 11"}
MOON_DIST:       150.76 [deg]
MOON_ILLUM:      39 [%]
GAL_COORDS:      214.02,  4.48 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      108.65,-21.25 [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 11 Apr 07 20:28:07 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     275087,   Seg_Num: 0
POINT_RA:        107.340d {+07h 09m 22s} (J2000)
POINT_DEC:        +1.077d {+01d 04' 35"} (J2000)
ROLL:            278.363d
IMG_START_DATE:  14201 TJD;   101 DOY;   07/04/11
IMG_START_TIME:  72996.19 SOD {20:16:36.19} UT,   242.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     198015398
X_OFFSET:        836 [pixels]
Y_OFFSET:        897 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       996
Y_GRB_POS:       1057
BINNING_INDEX:   1
IM_URL:          sw00275087000msuni0242.fits
SUN_POSTN:        19.94d {+01h 19m 45s}   +8.41d {+08d 24' 31"}
SUN_DIST:         87.37 [deg]   Sun_angle= -5.8 [hr] (East of Sun)
MOON_POSTN:      308.19d {+20h 32m 46s}  -22.22d {-22d 13' 02"}
MOON_DIST:       150.75 [deg]
MOON_ILLUM:      39 [%]
GAL_COORDS:      214.02,  4.48 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      108.65,-21.25 [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 11 Apr 07 20:28:26 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     275087,   Seg_Num: 0
POINT_RA:        107.340d {+07h 09m 22s} (J2000)
POINT_DEC:        +1.077d {+01d 04' 35"} (J2000)
ROLL:            278.363d
IMG_START_DATE:  14201 TJD;   101 DOY;   07/04/11
IMG_START_TIME:  72996.19 SOD {20:16:36.19} UT,   242.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     198015398
X_OFFSET:        836 [pixels]
Y_OFFSET:        897 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       996
Y_GRB_POS:       1057
BINNING_INDEX:   1
IM_URL:          sw00275087000msuni0242.fits
SUN_POSTN:        19.94d {+01h 19m 45s}   +8.41d {+08d 24' 32"}
SUN_DIST:         87.37 [deg]   Sun_angle= -5.8 [hr] (East of Sun)
MOON_POSTN:      308.20d {+20h 32m 47s}  -22.22d {-22d 12' 58"}
MOON_DIST:       150.75 [deg]
MOON_ILLUM:      39 [%]
GAL_COORDS:      214.02,  4.48 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      108.65,-21.25 [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 #6267
A. Moretti (INAF-OAB), S. D. Barthelmy (GSFC), P. J. Brown (PSU), D. N. Burrows (PSU), M. M. Chester (PSU), J. R. Cummings (NASA/UMBC), G. Cusumano (INAF-IASFPA), N. Gehrels (NASA/GSFC), S. T. Holland (CRESST/GSFC/USRA), J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA), V. Mangano (INAF-IASFPA), F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester), C. Pagani (PSU), D. M. Palmer (LANL), P. Romano (Univ. Bicocca & INAF-OAB), T. Sakamoto (NASA/ORAU), B. Sbarufatti (INAF-IASFPA), M. Stamatikos (NASA/ORAU), R. L. C. Starling (U Leicester), G. Tagliaferri (INAF-OAB), D. E. Vanden Berk (PSU), S. D. Vergani (DIAS-DCU) and H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team:
At 20:12:33 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 070411 (trigger=275087). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 107.338, +1.083 which is
```
   RA(J2000)  =  07h 09m 21s
   Dec(J2000) = +01d 04' 57"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows an initial weak peak starting at T-1 sec and fading by T+5 sec and then a stronger second peak from T+50 to T+90 sec with an amplitude of ~1000 cnts/sec in the 15-350 keV band.
The XRT began observing the field at 20:14:09 UT, 96 seconds after the BAT trigger. XRT found an uncatalogued X-ray source located at RA, Dec 107.3327, +1.0632 which is
```
   RA(J2000)  =  07h 09m 19.8s
   Dec(J2000) =  01d 03' 47.5"
```
with an uncertainty of 4.7 arcseconds (radius, 90% containment). This location is 74 arcseconds from the BAT on-board position, within the BAT error circle. The initial flux in the 2.5s image was 5.1e-09 erg/cm2/s (0.2-10 keV).
UVOT took a finding chart exposure of nominal 100 seconds with the White (160-650 nm) filter starting 244 seconds after the BAT trigger. An afterglow candidate has been found in the initial data products. The 2.7'x2.7' region for the list of sources generated on-board covers 100% of the XRT error circle. A source is detected at
```
 RA =  07:09:19.93
Dec = +01:03:52.6 
```
with an estimated uncertainty of +/-0.5 arcsec. The estimated magnitude in the White filter is 18.7. No correction has been made for the large, but uncertain extinction corresponding to a reddening of 0.3 mag.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 11 Apr 07 20:58:53 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     275087,   Seg_Num: 0
GRB_RA:          107.3329d {+07h 09m 19.89s} (J2000),
                 107.4268d {+07h 09m 42.43s} (current),
                 106.6872d {+07h 06m 44.93s} (1950)
GRB_DEC:          +1.0645d {+01d 03' 52.2"} (J2000),
                  +1.0524d {+01d 03' 08.6"} (current),
                  +1.1459d {+01d 08' 45.4"} (1950)
GRB_ERROR:       0.7 [arcsec radius, statistical only]
GRB_MAG:         18.70 +/- 0.50 [mag]
FILTER:          10, White
IMG_START_DATE:  14201 TJD;   101 DOY;   07/04/11
IMG_START_TIME:  72997.00 SOD {20:16:37.00} UT,   243.7 [sec] since BAT Trigger Time
SUN_POSTN:        19.96d {+01h 19m 50s}   +8.42d {+08d 24' 60"}
SUN_DIST:         87.34 [deg]   Sun_angle= -5.8 [hr] (East of Sun)
MOON_POSTN:      308.49d {+20h 33m 58s}  -22.13d {-22d 07' 31"}
MOON_DIST:       150.60 [deg]
MOON_ILLUM:      38 [%]
GAL_COORDS:      214.03,  4.47 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      108.64,-21.26 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT UVOT Position Notice.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        Uncertain reddening E(B-V)=0.3

GCN Circular #6268
D. A. Kann, S. Schulze, S. Klose (TLS Tautenburg) and J. Greiner (MPE) report:
The location of the Swift GRB 070411 (Moretti et al., GCN 6267) was observed in good conditions but at high airmass with the Tautenburg 1.34m Schmidt Telescope in Rapid Response Mode (Klose et al., GCN 3609) upon receipt of the BAT position.
The first image (Rc Band, 180 sec integration) was started at 20:18:15 UT, 5 minutes and 42 seconds after the burst trigger.
We confirm a bright stationary source in the flight-localized XRT error circle, in accordance with the UVOT position (Moretti et al., GCN 6267). The afterglow was discovered independently of the UVOT observation.
Further analysis and observations are in progress.
This message may be cited.
GCN Circular #6269
E.S. Rykoff (U Mich), W. Rujopakarn (Seward), R. Quimby (U Texas), B. E. Schaefer (Louisiana State), H. Swan (U Mich), S.A. Yost (U Mich), report on behalf of the ROTSE collaboration:
ROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia, responded to GRB 070411 (Swift trigger 275087, GCN 6267, Moretti, et al.). The first image was at 20:15:25.1 UT, 172 s after the burst; the response was delayed due to a GCN connection problem. We took 10 5s exposures followed by 50+ 20s exposures. The unfiltered images are calibrated relative to USNO B1.0, and no correction has been made for the large Galactic extinction in the direction of the burst.
We confirm the afterglow candidate reported by Moretti, et al. (GCN 6267) and Kann, et al. (GCN 6268). The afterglow was marginally detected in the first few coadded images (stacking 10 images at a time). We see the afterglow brighten significantly during our observations, to a peak of 17.7+/-0.1 mag, around 900s after the burst; due to the faint afterglow, our time resolution is very coarse.
```
start UT     exptime  tstart-tburst (s)   mag
----------------------------------------------------------
20:15:25.2   50.0       172             18.2+/-0.4
20:21:53.7   200.0      560             18.5+/-0.4
20:26:50.0   200.0      856             17.7+/-0.1
20:31:45.8   200.0      1152            18.6+/-0.4
```
A jpeg image is available at http://www.rotse.net/images/gsb275087_3c031-040_key.jpg
Continuing observations are in progress.
GCN Circular #6270
H. Mikuz, J. Skvarc and B. Dintinjana on behalf of PIKA observing program at Crni Vrh Observatory:
We observed the afterglow of GRB 070411 (Moretti et al., GCN 6267) with 60 cm Cichocki robotic telescope at Crni Vrh Observatory, Slovenia. The 90 second exposure with R filter started at 20:14:01UT, 48 seconds after reception of the alert. We confirm optical afterglow found by UVOT. The object measured coordinates are ra=07:09:19.95, dec=+01:03:52.8, approximate brightness is R=17.9. The object faded on subsequent images.
Further photometric analysis is in progress.
GCN Circular #6271
A. Gomboc (Univ. of Ljubljana, Slovenia), A. Melandri, C.G. Mundell, I. A. Steele, D. Carter, M. Burgdorf, C. Guidorzi, A. Monfardini, S. Kobayashi, D. Bersier (Liverpool JMU) and N. Tanvir (Leicester University) report:
The 2-m Liverpool Telescope started observing the field of GRB070411 (Moretti et al. GCN 6267) in r'i'g' filters at 1 hr 20 min after the trigger time.
We detect the optical candidate identified by Moretti et al. (GCN 6267), Kann et al (GCN 6268), Rykoff et al. (GCN 6269) and Mikuz et al. (GCN 6270) in all filters.
We estimate the magnitude of the source to be R = 19.7 +/- 0.15 at t = 1.36 hr and I = 19.0 +/- 0.3 at t = 1.43 hr after the trigger time. Magnitudes were calibrated vs the USNOB1 catalogue.
Further analysis and observations are ongoing.
GCN Circular #6272
M. Jelinek (IAA-CSIC, Granada). J. A. Caballero (MPIA Heidelberg), A. de la Nuez (IAC La Laguna) and A. J. Castro-Tirado (IAA-CSIC),
report:
"We have observed the field of GRB070411 (Moretti et al. GCNC 6267) and its associated optical afterglow (Moretti et al., Kann et al. GCNC 6268, Rykoff et al. GCNC 6269, Mikuz et al. GCNC 6270, Gomboc et al. GCNC 6271) with the IAC80 telescope at Observatorio del Teide in BVR filters, starting at 21:45 UT, i.e. 1.5 h after the trigger.
The OA has faded to R=20.1+-0.1 (USNO-B1.0) at the epoch of our first observation."
GCN Circular #6274
C. Markwardt (GSFC/UMD), L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), A. Moretti (INAF-OAB), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC) on behalf of the Swift-BAT team:
Using the data set from T-119 to T+303 sec from recent telemetry downlinks, we report further analysis of BAT GRB 070411 (trigger #275087) (Moretti, et al., GCN Circ. 6267). The BAT ground-calculated position is RA, Dec = 107.345, 1.051 deg which is
```
   RA(J2000) = 7h 9m 22.9s 
   Dec(J2000) = 1d 3' 4.9" 
```
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 74%.
The mask-weighted lightcurve shows two main peaks. The first starts at T-60 sec, peaks at T+5 sec with a minimum at T+45 sec. The second peaks at T+65 sec and ends at T+135 sec. T90 (15-350 keV) is 101 +- 5 sec (estimated error including systematics).
The time-averaged spectrum from T-20 to T+109.5 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.71 +- 0.10. The fluence in the 15-150 keV band is 2.5 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+70.22 sec in the 15-150 keV band is 1.0 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
GCN Circular #6277
E. Berger (Carnegie) and H. Yee (Toronto) report:
"We obtained a 180 sec image in I-band with the IMACS instrument on the Magellan/Baade telescope on 2007 Apr 11.99 UT (3.55 hr after the burst). We detect the afterglow with I=20.3 mag relative to the USNO-B star located at RA=07:09:17.9453, DEC=+01:04:09.210 with I=17.8 mag."
GCN Circular #6278
E. Berger (Carnegie), M. Modjaz, A. Garg, R. Kirshner, P. Challis (Harvard), and A. Rest (NOAO) report:
"We obtained a 60 sec image in r-band with the LDSS3 instrument on the Magellan/Clay telescope on 2007 Apr 12.03 UT (4.57 hr after the burst). We detect the afterglow with r=20.8 mag relative to the USNO-B star located at RA=07:09:17.9453, DEC=+01:04:09.210 with R=17.6 mag."
GCN Circular #6283
Pall Jakobsson (U. Hertfordshire), Daniele Malesani, Christina C. Thoene, Johan P. U. Fynbo, Jens Hjorth (DARK, NBI), Andreas O. Jaunsen (U. Oslo), Michael I. Andersen (Potsdam) and Paul M. Vreeswijk (ESO), report on behalf of a larger collaboration:
Using FORS2 on the Very Large Telescope, we have obtained 2*10 min spectra (grism 1400V) of the optical afterglow of GRB 070411 (Moretti et al., GCN 6267) on April 12.05. The combined spectrum displays several absorption features, including Ly-alpha, C II, C II*, Si II, Si IV and Fe II, corresponding to a redshift of z = 2.954 (based on a preliminary wavelength calibration).
We thank the Paranal staff for excellent support, especially Leo Vanzi and Thomas Rivinius.
GCN Circular #6286
A. Moretti (INAF-OAB), P. Romano (Univ. Bicocca & INAF-OAB), C. Guidorzi (Univ. Bicocca & INAF-OAB) report on behalf of the Swift-XRT team:
We have analysed the first 4 orbits of Swift-XRT data obtained for GRB 070411 (trigger=275087, GCN 6267). At the moment the 1st orbit dataset is not complete. The currently available data consist of 4.2 ks in Photon Counting (PC) starting 500 seconds after the BAT trigger. Using PC data we obtain a refined position of:
```
RA(J2000) =  07h 09m 19.96s
Dec(J2000)= +01d 03' 51.8"
```
with an estimated uncertainty radius of 3.7 arcsec (90% containment). This location is 1.2 arcseconds from the UVOT position (GCN 6267).
The afterglow shows a decay which can be fitted well by a single power law (alpha=0.87+/-0.08) up to the end of the fourth orbit (t=17.0 ks). At this point the observed count rate was 6.8E-2 counts per second, corresponding to an unabsorbed flux of 5.2E-12 erg/cm2/sec. At 24 hours from the burst the expected afterglow unabsorbed flux is 1.1E-12 erg/cm2/sec (1.4E-2 counts per second).
The spectrum formed from the PC data can be modelled with a an absobed power-law of photon index Gamma = 2.1 +/- 0.2 and and an absorption column density consistent with the Galactic value (2.9+/-0.9 E21 cm^-2; Dickey & Lockman, 1990).
All errors are quoted at 90% confidence level.
This circular is an official product of the Swift-XRT team.

GCN Circular #6288
H. Mikuz, J. Skvarc and B. Dintinjana on behalf of PIKA observing program at Crni Vrh Observatory:
Following the GCN 6270, we performed the analysis of images, obtained with R and B photometric filters. Photometry results are given in table below. Time refers to exposure start.

Time (UT)    h  m  s    Exposure (s)  Mag.   Err.  Filter
2007 Apr 11 20:14:00.8      90        18.7   0.2   R
2007 Apr 11 20:19:31.8      90        18.2   0.2   R
2007 Apr 11 20:25:02.7      90        18.4   0.2   R
2007 Apr 11 20:30:33.6      90        18.8   0.3   R
2007 Apr 11 20:36:04.3      90        19.7   0.7   R
2007 Apr 11 20:41:35.2      90        not detected R

2007 Apr 11 20:16:00.9     180        19.9   0.7   B
2007 Apr 11 20:21:32.0     180        19.1   0.3   B
2007 Apr 11 20:27:03.0     180        19.3   0.3   B
2007 Apr 11 20:32:33.9     180        19.9   0.6   B
2007 Apr 11 20:38:04.6     180        not detected B
2007 Apr 11 20:43:35.3     180        not detected B

The magnitudes are derived using comparison stars from the USNO-B1 catalogue. The 3-sigma limiting magnitude in R filter is around magnitude 19.8, and about 20.0 in B filter. Fits images are available at http://www.observatorij.org/Data/GRB/2007-04-11/GRB070411.tgz

GCN Circular #6291
S.R.Oates (UCL-MSSL) and A. Moretti (INAF-OAB) report on behalf of the Swift/UVOT team:
The Swift/UVOT began observing the field of GRB 070411 on 2007-04-11 at 20:16:37 UT, 243s after the BAT trigger (Moretti et al., GCN 6267). A weak afterglow is detected in the WHITE, V and B filters at a refined position:

RA(J2000)  =  07:09:19.903
Dec(J2000) = +01:03:52.95

The magnitudes and 3 sigma upper limits are provided in the table below. The numbers in square brackets represent the significance of the detections.

Filter  Start(s)   End(s)      Exposure    Magnitude
-----------------------------------------------------------------
WHITE   242.9      342.7       98.2      18.76 +/- 0.13		[8.3]
WHITE   4418.0     4617.8      196.6     20.56   (3sigma UL)

V       349.2      368.9       19.5      17.40 +/- 0.33		[3.3]
V       4827.9     4911.8      82.6      18.81   (3sigma UL)

B       445.9      455.7       9.6       19.02 +/- 0.65	        [1.8]
B       4213.5     4413.2      196.6   	 20.56 +/- 0.51         [2.1]

U       421.5      4208.2      216.1     19.87   (3sigma UL)

UVW1    397.5      16931.8     833.9     20.89   (3sigma UL)

UVM2    373.1      16297.4     1326.0 	 21.38   (3sigma UL)

UVW2    474.9      4823.2      216.1     20.37   (3sigma UL)
------------------------------------------------------------------

These magnitudes are not corrected for the Galactic reddening of E(B-V)=0.285. The value of the Galactic reddening is uncertain as the burst lies at a Galactic latitude of +5 degrees.

GCN Report 44.2
GCN_Report 44.2 has been posted: http://gcn.gsfc.nasa.gov/reports/report_44_2.pdf by A. Moretti at INAF-OAB titled: "Swift Observations of GRB 070411"
GCN Report 44.1
GCN_Report 44.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_44_1.pdf by A. Moretti at INAF-OAB titled: "Swift Observations of GRB 070411"
Correction: It should have been 44.1, not 44.2
GCN Circular #6295
SUBJECT: GRB 070411: TLS data shows plateau, flares DATE: 07/04/13 00:48:22 GMT FROM: Alexander Kann at TLS Tautenburg
D. A. Kann, U. Laux, S. Klose, H. Meusinger, S. Schulze (TLS Tautenburg) and J. Greiner (MPE, Garching) report:
The afterglow of the Swift GRB 070411 (Moretti et al., GCN 6267) was observed with the Tautenburg 1.34m Schmidt telescope in RRM mode starting 342 seconds after the trigger (Kann et al., GCN 6268).
A total of 18 observations were obtained before the afterglow become unobservable. We performed aperature photometry vs. two unsaturated and isolated USNO B1.0 stars (R1 magnitudes):
RA = 07:09:17.16, Dec. = +01:04:35.9, assuming R = 15.55
RA = 07:09:28.54, Dec. = +01:03:57.1, assuming R = 16.25
We derive the following magnitudes (mean exposure times after the burst have been derived logarithmically):
```
   dt           Start Exposure  R mag   dR
(days)          (SOD) (seconds)

0.0049994	73095	180	18.03	0.05
0.0076498	73324	180	18.12	0.03
0.0103234	73555	180	18.18	0.03
0.0129739	73784	180	18.17	0.05
0.0156244	74013	180	18.43	0.07
0.0182864	74243	180	18.79	0.05
0.0209485	74473	180	18.83	0.07
0.0235989	74702	180	18.95	0.08
0.0262494	74931	180	19.23	0.07
0.0288999	75160	180	19.38	0.09
0.0315503	75389	180	19.75	0.12
0.0342008	75618	180	20.00	0.16
0.0368512	75847	180	19.83	0.12
0.0395017	76076	180	19.88	0.15
0.0421522	76305	180	20.13	0.19
0.0472965	76540	600	20.64	0.23
0.0548081	77189	600	19.91	0.14
0.0623197	77838	600	19.96	0.15
```
Adding further R and CR data (Rykoff et al., GCN 6269, Gomboc et al., GCN 6271, Jelinek, Nuez, & Castro-Tirado, GCN 6272, Berger et al., GCN 6278, Mikuz, Skvarc, & Dintinjana, GCN 6288), we find:
The afterglow may be rising early on, looking at the earliest detections from Crni Vrh, ROTSE and Tautenburg.
The afterglow then goes over into a plateau phase (decay alpha= 0.14 +/- 0.1). In our data, we do not see the strong rebrightening detected by ROTSE (Rykoff et al., GCN 6269).
At 0.014 +/- 0.001 days, the afterglow breaks and begins a decay with alpha = 1.54 +\- 0.16 up to about 0.03 days, where a possible flare occurs.
At about 0.05 days, the afterglow seems to rebrighten strongly, our data here are in full accordance with those of the Liverpool telescope (Gomboc et al., GCN 6271) and the IAC80 (Jelinek, Nuez, & Castro-Tirado, GCN 6272).
Further photometric follow-up of this GRB is warranted.
This message may be cited.
GCN Circular #6319
P. Ferrero, S. Klose, D. A. Kann and S. Schulze (TLS Tautenburg) report on behalf of a larger collaboration
The afterglow of GRB 070411 (Moretti et al., GCN 6267; Kann et al., GCN 6268) was observed with VIMOS at VLT/UT3 in imaging mode. A 150 second observation was obtained in the Rc filter at 3.1498 days after the GRB. The afterglow is clearly detected. We measure Rc = 24.22 +/- 0.13 versus nearby comparison stars.
We thank D. Malesani for supplying the magnitudes of the comparison stars and the ESO staff for their excellent support.
This message may be cited.
GCN Circular #6335
Jan Strobl (ASU Ondrejov), Martin Jelinek (IAA CSIC Granada), Martin Nekola, Filip Munz, Rene Hudec (ASU) and Petr Kubanek (IAA, U. Valencia)
report
The robotic telescope BART in Ondrejov followed automatically the GRB 070411 (Moretti et al. GCN 6267), with the first exposure starting 55.7s af- ter the GRB trigger (15.9s after receiving the message).
The beginning of the (unfiltered) optical observa- tion is simultaneous to the second gamma-ray peak of this ~100s long GRB (Markwardt et al. GCN6274).
The optical transient (Moretti et al. GCN 6267, Kann et al. GCN6268) was not detected, giving the following limits:
```
start   end     limit	note
-----------------------------
55.7s   85.7s   R>15.4  30s, simultaneous to gamma
55.7s  167.9s   R>16.0  3x30s
```
This message may be cited
GCN Circular #6343
D. Malesani (DARK/NBI), E. Rol (Univ. Leicester), L. A. Antonelli (INAF/OAR), J.P.U. Fynbo (DARK/NBI), P.A. Curran (UVA), K. Wiersema (UVA), A.J. Levan (Univ. Warwick), N.R. Tanvir (Univ. Leicester), V. Testa (INAF/OAR), E. Palazzi (INAF/IASF Bo), A.O. Jaunsen (Univ. Oslo), C.C. Thoene (DARK/NBI), J. Hjorth (DARK/NBI), P.M. Vreeswijk (ESO), report:
We have observed the optical afterglow of GRB 070411 (Moretti et al., GCN 6267), using the NOT, VLT, TNG, and WHT telescopes, in the R band.
Observations were carried out at several epochs, between 0.04 and 8 days after the burst. Analysis of the light curve reveals a clear steepening at ~1 day after the GRB. The late-time slope alpha ~ 1.4 is well constrained by our measurements (see also Ferrero et al., GCN 6319), and has a value flatter than expected from post-jet break models (alpha >~ 2).
We encourage observations at X-ray wavelengths to test for the presence of any break in the X-ray light curve.
We acknowledge support from the observers and the staff at the NOT, VLT, TNG, and WHT telescopes.
GCN Circular #6346
J. Prieto (Ohio State), P. Garnavich (Notre Dame), J. Hill (LBTO/UAz), X. Fan, J. Harris (U Ariz), X. Dai, P. Martini, K. Z. Stanek (Ohio State), R. M. Wagner (LBTO/OSU), J. Rhoads (Ariz State), S. Herbert-Fort (UAz) report:
The Large Binocular Telescope (LBT) imaged the position of the GRB 070411 afterglow (Moretti et al, GCN 6267; Kann et al. GCN 6268) with the LBC-blue CCD camera (http//lbc.mporzio.astro.it) and 8.4-m SX mirror on 2007 April 15.145 (UT). Ten dithered, 200 second exposures were obtained with the Sloan-r filter in 0.7" seeing. A point source within 0.1" of the Swift/UVOT position is clearly detected in each image.
In the combined image we find the afterglow to be 5.431 magnitudes fainter than the unsaturated star at RA=7:09:23.35 DEC=1:04:09.98 and listed in the USNO-B catalog at R2=18.52 mag. An out-of-focus image shows that this star is 0.916 mag fainter than the star used by Berger, Modjaz & Garg et al. (GCN 6278) implying the two calibrations are consistent. So we find the afterglow brightness to be r=23.95+/-0.05 mag. 3.30 days after the burst.
Image subtraction of individual frames shows no significant variability (<0.10 mag) on time-scale between 4 minutes and an 40 minutes.
The fading between the Berger et al. observation and the LBT image is consistent with a power-law decay index of 1.0, but note the possibility of a break reported by Malesani et al. (GCN 6343).
The LBT image can be found at: http://www.nd.edu/~pgarnavi/grb070411/grb070411_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
```
This message may be cited
GCN Circular #6349
XMM-Newton will observe GRB 070411 at location (RA=07h 09m 19.93s DEC=+01d 03' 52.6", J2000), starting at 09:45 UT, on April 28, 2007, for an exposure of 20000 seconds.
GCN Circular #6350
D. A. Perley, J. S. Bloom, R. J. Foley, and D. Kocevski (UC Berkeley) report:
On the night of 2007 April 16 (UT) we imaged the field of GRB 070411 (Moretti et al, GCN 6267) with Keck I / LRIS, in a series of g- and R-band exposures starting at 06:19 UT, 4.42 days after the GRB trigger under poor seeing conditions. The afterglow (GCN 6267; Kann et al, GCN 6268) is detected in a stacked image. Calibrating relative to the same USNO-B star used by Garnavich et al (GCN 6346) at RA=7:09:23.35 DEC=1:04:09.98, we measure an afterglow magnitude of R = 24.78 +/- 0.26.
GCN Circular #6351
P. Garnavich (Notre Dame), J. Prieto (Ohio State), J. Hill (LBTO/UAz), X. Fan (U Ariz), X. Dai, K. Z. Stanek (Ohio State), R. M. Wagner (LBTO/OSU), J. Rhoads (Ariz State), J. Bechtold (UAz), R. Gredel (MPIA), A. Grazian (Rome) report:
The Large Binocular Telescope (LBT) imaged the position of the GRB 070411 afterglow (Moretti et al, GCN 6267; Kann et al. GCN 6268) with the LBC-blue CCD camera (http//lbc.mporzio.astro.it) and 8.4-m SX mirror on 2007 April 22.14 (UT). Ten dithered, 200 second exposures were obtained with the Sloan-r filter in poor seeing and a bright sky background. No afterglow is detected and we estimate a 3-sigma upper-limit of r>25.3 mag.
Extrapolating the power-law decay found by Prieto et al. (GCN 6346) to 10.3 days after the burst, we expected an afterglow brightness of r=25.1+/-0.2 mag. Our non-detection is therefore marginal confirmation of a break in the light curve as reported by Malesani et al. (GCN 6343). The Keck observation (Perley et al GCN 6350) on day 4.4 also supports an increase in the decay rate.
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
```
This message may be cited
GCN Circular #6487
Klotz, A. (CESR-OMP), Boer M. (OHP), Atteia J.L. (LATT-OMP) report:
We imaged the field of GRB 070411 detected by SWIFT (trigger 275087) 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 45.6s after the GRB trigger (5.7s after the notice) when the burst was still active. The elevation of the field decreased from from 33 degrees above horizon and weather conditions were poor (cloudy).
The date of trigger : t0 = 2007-04-11T20:12:33.120
The first image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39). We do not detect the UVOT candidate position (Moretti et al., GCN 6267) with a limiting magnitude of: t0+45.6s to t0+105.6s : R > 14.6
The second image is 30.0s exposure in tracking mode: t0+112.6s to t0+142.6s : R > 15.5
Further images have no significant higher limiting magnitude.
Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction.
This message may be cited.

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Jochen Greiner, last update: 08-Jun-2007 [Disclaimer]