Gamma-ray Burst 080411

(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:     Fri 11 Apr 08 21:15:49 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     309010,   Seg_Num: 0
GRB_RA:           38.018d {+02h 32m 04s} (J2000),
                  38.040d {+02h 32m 10s} (current),
                  37.888d {+02h 31m 33s} (1950)
GRB_DEC:         -71.342d {-71d 20' 30"} (J2000),
                 -71.306d {-71d 18' 20"} (current),
                 -71.562d {-71d 33' 41"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       703 [cnts]    Image_Peak=77 [image_cnts]
TRIGGER_DUR:     0.064 [sec] 
TRIGGER_INDEX:   10418     E_range: 25-100 keV
BKG_INTEN:       50053 [cnts]
BKG_TIME:        76517.28 SOD {21:15:17.28} UT
BKG_DUR:         8 [sec]
GRB_DATE:        14567 TJD;   102 DOY;   08/04/11
GRB_TIME:        76532.32 SOD {21:15:32.32} UT
GRB_PHI:         -162.96 [deg]
GRB_THETA:        29.13 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     14.31 [sigma]
IMAGE_SIGNIF:    8.14 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2 +21  +0  +0 -15  +1 
SUN_POSTN:        20.67d {+01h 22m 40s}   +8.70d {+08d 41' 53"}
SUN_DIST:         80.84 [deg]   Sun_angle= -1.2 [hr] (East of Sun)
MOON_POSTN:      102.19d {+06h 48m 45s}  +26.71d {+26d 42' 49"}
MOON_DIST:       107.52 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      292.11,-43.61 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      322.12,-71.38 [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 = 14.26,-19.40 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 11 Apr 08 21:20:41 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     309010,   Seg_Num: 0
GRB_RA:           38.018d {+02h 32m 04s} (J2000),
                  38.040d {+02h 32m 10s} (current),
                  37.888d {+02h 31m 33s} (1950)
GRB_DEC:         -71.342d {-71d 20' 30"} (J2000),
                 -71.306d {-71d 18' 20"} (current),
                 -71.562d {-71d 33' 41"} (1950)
GRB_DATE:        14567 TJD;   102 DOY;   08/04/11
GRB_TIME:        76532.58 SOD {21:15:32.58} UT
TRIGGER_INDEX:   10418
GRB_PHI:         -162.96 [deg]
GRB_THETA:        29.13 [deg]
DELTA_TIME:      257.00 [sec]
TRIGGER_DUR:     0.064 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     14.31 [sigma]
IMAGE_SIGNIF:    8.14 [sigma]
LC_URL:          sw00309010000msb.lc
SUN_POSTN:        20.67d {+01h 22m 41s}   +8.70d {+08d 41' 58"}
SUN_DIST:         80.84 [deg]   Sun_angle= -1.2 [hr] (East of Sun)
MOON_POSTN:      102.24d {+06h 48m 58s}  +26.71d {+26d 42' 24"}
MOON_DIST:       107.52 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      292.11,-43.61 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      322.12,-71.38 [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 = 14.26,-19.40 [deg].  
COMMENTS:        The 3rd packet (of 3) was missing in the lightcurve data stream.

Full lightcurve, from http://gcn.gsfc.nasa.gov/notices_s/sw00309010000msb.gif

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 11 Apr 08 21:29:12 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     309010,   Seg_Num: 0
GRB_RA:           37.9860d {+02h 31m 56.6s} (J2000),
                  38.0083d {+02h 32m 01.9s} (current),
                  37.8542d {+02h 31m 25.0s} (1950)
GRB_DEC:         -71.3021d {-71d 18' 07.5"} (J2000),
                 -71.2658d {-71d 15' 56.8"} (current),
                 -71.5217d {-71d 31' 18.2"} (1950)
GRB_ERROR:       4.3 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       4.40e-07 [erg/cm2/sec]
GRB_SIGNIF:      17.34 [sigma]
IMG_START_DATE:  14567 TJD;   102 DOY;   08/04/11
IMG_START_TIME:  76602.47 SOD {21:16:42.47} UT,   70.1 [sec] since BAT Trigger Time
TAM[0-3]:        327.61 237.24 261.26 243.44
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:        20.67d {+01h 22m 42s}   +8.70d {+08d 42' 06"}
SUN_DIST:         80.81 [deg]   Sun_angle= -1.2 [hr] (East of Sun)
MOON_POSTN:      102.33d {+06h 49m 20s}  +26.69d {+26d 41' 41"}
MOON_DIST:       107.52 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      292.09,-43.65 [deg] galactic lon,lat of the burst
ECL_COORDS:      322.23,-71.36 [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:     Fri 11 Apr 08 21:29:22 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     309010,   Seg_Num: 0
GRB_RA:           37.9860d {+02h 31m 56.6s} (J2000),
                  38.0083d {+02h 32m 01.9s} (current),
                  37.8542d {+02h 31m 25.0s} (1950)
GRB_DEC:         -71.3021d {-71d 18' 07.5"} (J2000),
                 -71.2658d {-71d 15' 56.8"} (current),
                 -71.5217d {-71d 31' 18.2"} (1950)
GRB_ERROR:       4.3 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       301 [cnts]
IMG_START_DATE:  14567 TJD;   102 DOY;   08/04/11
IMG_START_TIME:  76602.47 SOD {21:16:42.47} UT,   70.1 [sec] since BAT Trigger Time
CENTROID_X:      226.77,  raw= 227  [pixels]
CENTROID_Y:      295.00,  raw= 295  [pixels]
ROLL:            342.60 [deg]
GAIN:            4
MODE:            2, Short Image mode
WAVEFORM:        134
EXPO_TIME:       0.10 [sec]
GRB_POS_XRT_Y:   -7.07
GRB_POS_XRT_Z:   -178.03
IMAGE_URL:       sw00309010000msxps_rw.img
SUN_POSTN:        20.67d {+01h 22m 42s}   +8.70d {+08d 42' 06"}
SUN_DIST:         80.81 [deg]   Sun_angle= -1.2 [hr] (East of Sun)
MOON_POSTN:      102.33d {+06h 49m 20s}  +26.69d {+26d 41' 40"}
MOON_DIST:       107.52 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      292.09,-43.65 [deg] galactic lon,lat of the burst
ECL_COORDS:      322.23,-71.36 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN Circular #7584
F. E. Marshall (NASA/GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), O. Godet (U Leicester), S. T. Holland (CRESST/USRA/GSFC), H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (CRESST/GSFC/UMD), K. M. McLean (GSFC/UMD), C. Pagani (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL), M. Stamatikos (NASA/ORAU), R. L. C. Starling (U Leicester), T. N. Ukwatta (GSFC/GWU), L. Vetere (PSU) and P. A. Ward (MSSL-UCL) report on behalf of the Swift Team:
At 21:15:32 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 080411 (trigger=309010). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 38.018, -71.342 which is
```
   RA(J2000)  =  02h 32m 04s
   Dec(J2000) = -71d 20' 30"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The TDRSS BAT lightcurve shows the burst starting with a fast rise from background to ~13,000 counts/sec in approximately 0.5 sec. There are several peaks after that with the fourth peak (T+19 sec) at 75,000 cnts/sec. There are several more peaks after that lasting out to at least T+70 sec.
The XRT began observing the source at 21:16:42 UT (71 s after the trigger). The XRT centroided on something very bright. We have lost most of our prompt diagnostic messages because the spacecraft switched from TDRSS telemetry to Malindi telemetry shortly after the burst, and our prompt image does not include the source. However, the information within the header indicates that the source is located near the center of the XRT field of view, and is therefore probably real. If real, the position is
```
GRB_RA:           37.9860d {+02h 31m 56.6s} (J2000),
GRB_DEC:         -71.3021d {-71d 18' 07.5"} (J2000),
```
with an uncertainty of 4.3 arcseconds (90% confidence radius), and the flux during this image was approximately 4.4e-7 cgs (~ 10 Crabs) in the 0.1 s image. The XRT position is 148 arcseconds from the BAT position.
No UVOT data for this burst are currently available.
Burst Advocate for this burst is F. E. Marshall (marshall AT milkyway.gsfc.nasa.gov). 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:     Fri 11 Apr 08 22:28:29 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     309010,   Seg_Num: 0
POINT_RA:         38.095d {+02h 32m 23s} (J2000)
POINT_DEC:       -71.375d {-71d 22' 28"} (J2000)
POINT_ROLL:      342.566d
IMG_START_DATE:  14567 TJD;   102 DOY;   08/04/11
IMG_START_TIME:  80733.82 SOD {22:25:33.82} UT,   4201.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.985
N_STARS:         25
X_OFFSET:        656 [pixels]
Y_OFFSET:        324 [pixels]
X_MAX:           1615 [pixels]
Y_MAX:           1283 [pixels]
DET_THRESH:      17
PHOTO_THRESH:    9
SL_URL:          sw00309010000msufc4201.fits
SUN_POSTN:        20.71d {+01h 22m 51s}   +8.72d {+08d 42' 60"}
SUN_DIST:         80.90 [deg]   Sun_angle= -1.2 [hr] (East of Sun)
MOON_POSTN:      102.97d {+06h 51m 53s}  +26.61d {+26d 36' 31"}
MOON_DIST:       107.62 [deg]
MOON_ILLUM:      41 [%]
GAL_COORDS:      292.10,-43.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      322.03,-71.41 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 11 Apr 08 22:29:07 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     309010,   Seg_Num: 0
POINT_RA:         38.095d {+02h 32m 23s} (J2000)
POINT_DEC:       -71.375d {-71d 22' 28"} (J2000)
POINT_ROLL:      342.566d
IMG_START_DATE:  14567 TJD;   102 DOY;   08/04/11
IMG_START_TIME:  80733.82 SOD {22:25:33.82} UT,   4201.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.985
N_STARS:         25
X_OFFSET:        656 [pixels]
Y_OFFSET:        324 [pixels]
X_MAX:           1615 [pixels]
Y_MAX:           1283 [pixels]
DET_THRESH:      17
PHOTO_THRESH:    9
SL_URL:          sw00309010000msufc4201.fits
SUN_POSTN:        20.71d {+01h 22m 51s}   +8.72d {+08d 43' 00"}
SUN_DIST:         80.90 [deg]   Sun_angle= -1.2 [hr] (East of Sun)
MOON_POSTN:      102.98d {+06h 51m 55s}  +26.61d {+26d 36' 27"}
MOON_DIST:       107.63 [deg]
MOON_ILLUM:      41 [%]
GAL_COORDS:      292.10,-43.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      322.03,-71.41 [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:     Fri 11 Apr 08 22:30:20 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     309010,   Seg_Num: 0
POINT_RA:         38.095d {+02h 32m 23s} (J2000)
POINT_DEC:       -71.375d {-71d 22' 28"} (J2000)
ROLL:            342.566d
IMG_START_DATE:  14567 TJD;   102 DOY;   08/04/11
IMG_START_TIME:  80733.82 SOD {22:25:33.82} UT,   4201.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     229645536
X_OFFSET:        975 [pixels]
Y_OFFSET:        643 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1135
Y_GRB_POS:       803
BINNING_INDEX:   1
IM_URL:          sw00309010000msuni4201.fits
SUN_POSTN:        20.71d {+01h 22m 51s}   +8.72d {+08d 43' 01"}
SUN_DIST:         80.90 [deg]   Sun_angle= -1.2 [hr] (East of Sun)
MOON_POSTN:      102.99d {+06h 51m 58s}  +26.61d {+26d 36' 21"}
MOON_DIST:       107.63 [deg]
MOON_ILLUM:      41 [%]
GAL_COORDS:      292.10,-43.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      322.03,-71.41 [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:     Fri 11 Apr 08 22:30:35 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     309010,   Seg_Num: 0
POINT_RA:         38.095d {+02h 32m 23s} (J2000)
POINT_DEC:       -71.375d {-71d 22' 28"} (J2000)
ROLL:            342.566d
IMG_START_DATE:  14567 TJD;   102 DOY;   08/04/11
IMG_START_TIME:  80733.82 SOD {22:25:33.82} UT,   4201.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     229645536
X_OFFSET:        975 [pixels]
Y_OFFSET:        643 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1135
Y_GRB_POS:       803
BINNING_INDEX:   1
IM_URL:          sw00309010000msuni4201.fits
SUN_POSTN:        20.71d {+01h 22m 51s}   +8.72d {+08d 43' 02"}
SUN_DIST:         80.90 [deg]   Sun_angle= -1.2 [hr] (East of Sun)
MOON_POSTN:      102.99d {+06h 51m 58s}  +26.61d {+26d 36' 20"}
MOON_DIST:       107.63 [deg]
MOON_ILLUM:      41 [%]
GAL_COORDS:      292.10,-43.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      322.03,-71.41 [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:        If you have elected to receive attachments:  
COMMENTS:        The uvot_sources_image.fits.gz file does not exist; skipping the attachment.

GCN Circular #7586
T. Kruehler, A. Kupcu Yoldas, J. Greiner, C. Clemens, A. Yoldas (all MPE Garching) and G. Szokoly (Eoetvoes Univ., Budapest and MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 080411 detected by BAT (Marshall et al., GCN #7584) simultaneously in g'r'i'z'JHK with GROND mounted at the 2.2m ESO/MPI telescope at La Silla Observatory (Chile).
Observations started in twilight at 23:15 UT on April 11th, 2008, 2h after the burst.
We detect a new bright point source just at the edge of the XRT error circle (Marshall et al. GCN #7584) at
```
RA (J2000.0) = 02:31:55.20
DEC (J2000.0) = -71:18:07.6
```
with an uncertainty of 0.8".
The object is detected in all of the seven bands, implying a redshift smaller than 3.5.
Preliminary photometry yields an r' band magnitude of 16.5 calibrated against USNO field stars.
The given magnitude are not corrected for the Galactic foreground reddening of E(B-V)=0.03 mag (Schlegel et al., 1998).
GCN Circular #7587
Christina C. Thoene (DARK/NBI), Annalisa De Cia (Univ. Iceland), Daniele Malesani, and Paul M. Vreeswijk (DARK/NBI), report:
We observed the optical afterglow of GRB 080411 (Marshall et al., GCN 7584; Kruehler et al., GCN 7586) wih the ESO VLT equipped with FORS1 with grism 300V. In a 600 s exposure taken at large airmass (average of 2.45) the afterglow trace is clearly detected. The mean time of the observations is Apr 11.987 UT (2.4 hr after the trigger). In the acquisition image, we measure R = 17.25 based on archival zeropoints.
We detect very strong absorption lines from Mg II, Mg I, Fe II and several other ions at a redshift z = 1.03. Given the strength of the features, we consider this to be the redshift of the GRB. We caution that the wavelength calibration is based on archival data.
We acknowledge excellent support from the ESO staff, who carried out this difficult observation, in particular Swetlana Hubrig.
GCN Circular #7588
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team.
Using 1122 s of overlapping XRT Photon Counting mode and UVOT data for GRB 080411, 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 = 37.97852, -71.30188 which is equivalent to:
```
RA (J2000): 02h 31m 54.84s
Dec (J2000): -71d 18' 06.8"
```
with an uncertainty of 1.5 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 http://www.swift.ac.uk/xrt_positions/Goad.pdf), the current algorithm is an extension of this method.
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #7589
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and T. Cline on behalf of the Konus-Wind team report:
The long GRB 080411 (Swift-BAT trigger #309010: Marshall et al., GCN 7584) triggered Konus-Wind at T0=76532.496 s UT (21:15:32.496).
The burst light curve shows several pulses with a total duration of ~70s.
As observed by Konus-Wind the burst had a fluence of 6.29(-0.29, +0.31)x10^-5 erg/cm2, and a 64-ms peak flux measured from T0+17.936 s of (1.28 +/- 0.16)x10^-5 erg/cm2/s (both in the 20 keV - 2 MeV energy range).
The time-integrated spectrum of the burst (from T0 to T0+74.24 s) can be fitted (in the 20 keV-2 MeV range) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.51(-0.05, +0.04), and Ep = 259(-27, +35) keV (chi2 = 64.5/59 dof).
All the quoted errors are at the 90% confidence level.
Assuming z = 1.03 (Thoene et al., GCN 7587) and a standard cosmology model with H_0 = 70 km/s/Mpc, Omega_M = 0.27, Omega_\Lambda = 0.73, the isotropic energy release is E_iso ~1.81x10^53 erg, the maximum luminosity is (L_iso)_max ~7.48x10^52 erg/s, and Ep_rest ~524 keV.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.rssi.ru/LEA/GRBs/GRB080411_T76532/
GCN Circular #7590
O. Godet, A. P. Beardmore, K. Page (U. Leicester) reports on behalf the Swift-XRT team:
The XRT began observing the field of GRB 080411 (trigger=309010, Marshall et al., GCN Circ. 7584) at 21:16:42 UT, 71 seconds after the BAT trigger. We analysed the first orbit of WT data (0.9 s) at T0+209s and the first 4 orbits of PC data (~3.6 ks) from T0+4.2ks to T0+17.4ks.
The X-ray light-curve shows a broken power-law behaviour. Since there are no data between the WT and PC observations, it is difficult to constrain the initial decay and break time. The late decay from the PC data gives a decay slope of 0.98+/-0.05. Using ground data, we confirmed that the initial intense flux reported by Marshall et al. (GCN Circ. 7584) from the 0.1s image taken at T0+71s is real and is likely to correspond to the end of the activity observed in the BAT. That implies an initial rapid decay in the XRT light-curve.
The WT spectrum contains only 20 counts. So, the fitting parameters are not well constrained when the spectrum is fitted by an absorbed power-law (N_H < 4.6e21 cm^-2 in excess with respect to the Galactic absorption along the burst line of sight (5.7e20 cm^-2, Kalberla et al. 2005) and a photon index of 2.85 +1.54/-1.05). The PC spectrum from T0+4.2ks to T0_17.4ks is fitted well by an absorbed power-law with a photon index of 2.14 +/- 0.09 and an absorption column of (1.5 +/- 0.3)e21 cm^-2, in excess with respect to the Galactic one.
The observed (unabsorbed) flux in the 0.3-10 keV band is 7.1e-10 (1.7e-9) erg cm^-2 s^-1 for the WT spectrum and 7.2e-11 (1.1e-10) erg cm^-2 s^-1 for the PC spectrum.
The predicted XRT count rate at T0+1d (T0+3d) is 0.26 (0.07) count s^-1, which corresponds to an observed 0.3-10 keV flux of 2.7e-11 (7.1e-12) erg cm^-2 s^-1.
This is an official product of the Swift-XRT team.
GCN Circular #7591
G. Sato (GSFC/ISAS), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), F. E. Marshall (GSFC), K. McLean (GSFC/UMD), D. Palmer (LANL), T. Sakamoto (GSFC/UMBC), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU) (i.e. the Swift-BAT team):
Using the data set from T-187 to T+723 sec from recent telemetry downlinks, we report further analysis of BAT GRB 080411 (trigger #309010) (Marshall, et al., GCN Circ. 7584). The BAT ground-calculated position is RA, Dec = 37.961, -71.297 deg, which is
```
   RA(J2000)  =  02h 31m 50.6s 
   Dec(J2000) = -71d 17' 49.6" 
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 86%.
The mask-weighted light curve shows two clusters of overlapping peaks. The first starts at T+0.0 sec and rises to a peak in 1 sec. The second peak is at T+7 sec; the third at T+10 sec, and the 4th at T+19 sec at 25 cnt/cm2/sec (15-150 keV). The lightcurve returns to background before the beginning of the second cluster of peaks. The 5th peak starts at ~T+39 sec, rises linearly, peaking at ~T+41 src at 43 cnts/cm2/sec. There are two more much smaller peaks at T+55 and T+64 sec. The lightcurve returns to background by ~T+95 sec. There is a gap in the downlinked data from T+300 to T+420 sec. It appears that the burst has returned to background well before this gap, but should later downlinks show on-going activity, we will issue an updated circular. T90 (15-350 keV) is 56 +- 1 sec (estimated error including systematics).
The time-averaged spectrum from T-0.0 to T+84.3 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.75 +- 0.03. The fluence in the 15-150 keV band is 2.64 +- 0.01 x 10^-5 erg/cm2. The 1-sec peak photon flux measured from T+40.45 sec in the 15-150 keV band is 43.2 +- 0.9 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/309010/BA/
GCN Circular #7592
S. R. Oates and F. Marshall report on behalf of the Swift/UVOT team.
The Swift/UVOT observed the field of GRB 080411 starting at 4202s after the BAT trigger (Marshall et al., GCN 7584). We detect the afterglow in white, v, b, u and uvw2 filters at the position:
```
RA(J2000.0)  =  02:31:55.19
DEC(J2000.0) = -71:18:07.30
```
with an etimated uncertainty of 0.5 arcsec (radius, 90% confidence). This position is consistent with the optical afterglow position reported by GROND (Kruehler et al., GCN 7586). The UVOT did not perform observations in uvw1 and uvm2 filters. The following magnitudes were obtained:
```
Filter    T_Mid(s)   Expo(s)            Magnitude
-----------------------------------------------------
White      4251        98              17.01 +/- 0.03
White      22869       295             18.09 +/- 0.03
v          16808       177             18.05 +/- 0.12
b          4615        197             17.43 +/- 0.05
b          21653       295             18.39 +/- 0.09
u          4410        197             16.46 +/- 0.04
uvw2       16260       886             18.41 +/- 0.07
-----------------------------------------------------
```
The above magnitudes are not corrected for the Galactic extinction corresponding to a reddening of E_{B-V} = 0.04 mag (Schlegel et al., 1998, ApJS, 500, 525). The photometry is on the UVOT flight system described in Poole et al. (2008, MNRAS, 383, 627).
GCN Circular #7664
F.E. Marshall (NASA/GSFC), O. Godet (U. Leicester) and S.R. Oates (MSSL-UCL) report on behalf of the Swift team:
The XRT and UVOT instruments on Swift continue to detect GRB 080411 19 days after the BAT trigger (Marshall et al., GCN Circ. 7584). The X-ray light curve shows a broken power-law behaviour with breaks at about T+8 ks and T+240 ks and additional short-term features at late times. Since the latter break, the decay index has been 1.54 +/- 0.12, and the 0.6-10 keV flux at T+1600 ks was 1.3 x 10^-13 ergs/s/cm^2. The optical light curve also shows a similar broken power-law behaviour. At T+1600 ks the magnitude (uncorrected for Galactic extinction) in the broad-band white filter was 22.7 +/- 0.2 using the UVOT photometric system (Poole et al. MNRAS 383, 627 (2008)). Recently the decay index has been 1.30 +/- 0.03.
Additional Swift observations of GRB 080411 are planned. Since the optical afterglow is approaching the sensitivity limit for UVOT, ground-based observations are encouraged.
Please contact the Swift Burst Advocate for this burst at marshall AT milkyway.gsfc.nasa.gov if you desire additional information regarding the Swift followup of this burst.
GCN Report 152.1
GCN_Report 152.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_152_1.pdf by F.E. Marshall at NASA/GSFC titled: "Final Swift Observations on GRB 080411"
GCN Circular #8439
Aquib Moin (Curtin Institute of Radio Astronomy / Australia Telescope National Facility), Steven Tingay (Curtin Institute of Radio Astronomy), Chris Phillips (Australia Telescope National Facility), Gregory Taylor (University of New Mexico), Mark Wieringa (Australia Telescope National Facility) and Ralph Martin (Perth Observatory) report:
We observed the BAT refined position of the GRB 080411 (GCN 7591) at 4.8 and 8.456 GHz with the Australia Telescope Compact Array (ATCA) on June 01, 2008 between 03:43:05 UT and 09:43:35 UT.
We did not detect a radio source at the BAT position of the GRB 080411 (GCN 7591). The radio flux density at the GRB position is -0.101 +/- 0.324 mJy at 4.8 GHz and 0.188 +/- 0.374 mJy at 8.456 GHz (1-sigma).
The Australia Telescope Compact Array (/ Parkes telescope / Mopra telescope / Long Baseline Array) is part of the Australia Telescope which is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO.
See field image at:
http://astronomy.ivec.org/dokuwiki/doku.php/grb/grb_080411_field_image

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Jochen Greiner, last update: 29-Oct-2008 [Disclaimer]