Gamma-ray Burst 151029A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 29 Oct 15 08:04:13 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     662086,   Seg_Num: 0
POINT_RA:         38.534d {+02h 34m 08s} (J2000)
POINT_DEC:       -35.365d {-35d 21' 54"} (J2000)
IMG_START_DATE:  17324 TJD;   302 DOY;   15/10/29
IMG_START_TIME:  28264.38 SOD {07:51:04.38} UT
COUNTS:          2    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        1    Max_iter_allowed= 4
ERROR_CODE:      1
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        No source found in the image.

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 29 Oct 15 08:05:50 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     662086,   Seg_Num: 0
POINT_RA:         38.535d {+02h 34m 08s} (J2000)
POINT_DEC:       -35.365d {-35d 21' 53"} (J2000)
POINT_ROLL:      173.225d
IMG_START_DATE:  17324 TJD;   302 DOY;   15/10/29
IMG_START_TIME:  28270.93 SOD {07:51:10.93} UT
FILTER:          10, White
BKG_MEAN:        1.544
N_STARS:         36
X_OFFSET:        408 [pixels]
Y_OFFSET:        636 [pixels]
X_MAX:           1367 [pixels]
Y_MAX:           1595 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00662086000msufc467797870.fits
SUN_POSTN:       213.28d {+14h 13m 07s}  -13.38d {-13d 22' 48"}
SUN_DIST:        131.05 [deg]   Sun_angle= 11.6 [hr] (West of Sun)
MOON_POSTN:       59.69d {+03h 58m 45s}  +15.96d {+15d 57' 51"}
MOON_DIST:        54.99 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      239.93,-66.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       20.29,-47.15 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 29 Oct 15 08:06:20 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     662086,   Seg_Num: 0
POINT_RA:         38.535d {+02h 34m 08s} (J2000)
POINT_DEC:       -35.365d {-35d 21' 53"} (J2000)
POINT_ROLL:      173.225d
IMG_START_DATE:  17324 TJD;   302 DOY;   15/10/29
IMG_START_TIME:  28270.93 SOD {07:51:10.93} UT
FILTER:          10, White
BKG_MEAN:        1.544
N_STARS:         36
X_OFFSET:        408 [pixels]
Y_OFFSET:        636 [pixels]
X_MAX:           1367 [pixels]
Y_MAX:           1595 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00662086000msufc467797870.fits
SUN_POSTN:       213.28d {+14h 13m 07s}  -13.38d {-13d 22' 49"}
SUN_DIST:        131.05 [deg]   Sun_angle= 11.6 [hr] (West of Sun)
MOON_POSTN:       59.69d {+03h 58m 47s}  +15.96d {+15d 57' 54"}
MOON_DIST:        54.99 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      239.93,-66.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       20.29,-47.15 [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 29 Oct 15 08:07:12 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     662086,   Seg_Num: 0
POINT_RA:         38.535d {+02h 34m 08s} (J2000)
POINT_DEC:       -35.365d {-35d 21' 53"} (J2000)
ROLL:            173.225d
IMG_START_DATE:  17324 TJD;   302 DOY;   15/10/29
IMG_START_TIME:  28270.93 SOD {07:51:10.93} UT
FILTER:          10, White
EXPOSURE_ID:     467797886
X_OFFSET:        727 [pixels]
Y_OFFSET:        955 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       887
Y_GRB_POS:       1115
BINNING_INDEX:   1
IM_URL:          sw00662086000msuni467797886.fits
SUN_POSTN:       213.28d {+14h 13m 07s}  -13.38d {-13d 22' 49"}
SUN_DIST:        131.05 [deg]   Sun_angle= 11.6 [hr] (West of Sun)
MOON_POSTN:       59.70d {+03h 58m 49s}  +15.97d {+15d 57' 59"}
MOON_DIST:        55.00 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      239.93,-66.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       20.29,-47.15 [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:     Thu 29 Oct 15 08:07:32 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     662086,   Seg_Num: 0
POINT_RA:         38.535d {+02h 34m 08s} (J2000)
POINT_DEC:       -35.365d {-35d 21' 53"} (J2000)
ROLL:            173.225d
IMG_START_DATE:  17324 TJD;   302 DOY;   15/10/29
IMG_START_TIME:  28270.93 SOD {07:51:10.93} UT
FILTER:          10, White
EXPOSURE_ID:     467797886
X_OFFSET:        727 [pixels]
Y_OFFSET:        955 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       887
Y_GRB_POS:       1115
BINNING_INDEX:   1
IM_URL:          sw00662086000msuni467797886.fits
SUN_POSTN:       213.28d {+14h 13m 07s}  -13.38d {-13d 22' 50"}
SUN_DIST:        131.05 [deg]   Sun_angle= 11.6 [hr] (West of Sun)
MOON_POSTN:       59.71d {+03h 58m 50s}  +15.97d {+15d 58' 01"}
MOON_DIST:        55.00 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      239.93,-66.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       20.29,-47.15 [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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 29 Oct 15 08:11:22 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     662086,   Seg_Num: 0
POINT_RA:         38.537d {+02h 34m 09s} (J2000)
POINT_DEC:       -35.367d {-35d 22' 00"} (J2000)
POINT_ROLL:      173.222d
IMG_START_DATE:  17324 TJD;   302 DOY;   15/10/29
IMG_START_TIME:  28483.07 SOD {07:54:43.07} UT
FILTER:          7, U
BKG_MEAN:        0.475
N_STARS:         57
X_OFFSET:        168 [pixels]
Y_OFFSET:        396 [pixels]
X_MAX:           1607 [pixels]
Y_MAX:           1835 [pixels]
DET_THRESH:      6
PHOTO_THRESH:    3
SL_URL:          sw00662086000msufc467798083.fits
SUN_POSTN:       213.28d {+14h 13m 08s}  -13.38d {-13d 22' 53"}
SUN_DIST:        131.05 [deg]   Sun_angle= 11.6 [hr] (West of Sun)
MOON_POSTN:       59.75d {+03h 58m 59s}  +15.97d {+15d 58' 23"}
MOON_DIST:        55.02 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      239.93,-66.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       20.30,-47.15 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 29 Oct 15 08:11:42 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     662086,   Seg_Num: 0
POINT_RA:         38.537d {+02h 34m 09s} (J2000)
POINT_DEC:       -35.367d {-35d 22' 00"} (J2000)
POINT_ROLL:      173.222d
IMG_START_DATE:  17324 TJD;   302 DOY;   15/10/29
IMG_START_TIME:  28483.07 SOD {07:54:43.07} UT
FILTER:          7, U
BKG_MEAN:        0.475
N_STARS:         57
X_OFFSET:        168 [pixels]
Y_OFFSET:        396 [pixels]
X_MAX:           1607 [pixels]
Y_MAX:           1835 [pixels]
DET_THRESH:      6
PHOTO_THRESH:    3
SL_URL:          sw00662086000msufc467798083.fits
SUN_POSTN:       213.28d {+14h 13m 08s}  -13.38d {-13d 22' 53"}
SUN_DIST:        131.05 [deg]   Sun_angle= 11.6 [hr] (West of Sun)
MOON_POSTN:       59.75d {+03h 59m 00s}  +15.97d {+15d 58' 25"}
MOON_DIST:        55.02 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      239.93,-66.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       20.30,-47.15 [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 29 Oct 15 08:12:35 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     662086,   Seg_Num: 0
POINT_RA:         38.537d {+02h 34m 09s} (J2000)
POINT_DEC:       -35.367d {-35d 22' 00"} (J2000)
POINT_ROLL:      173.223d
IMG_START_DATE:  17324 TJD;   302 DOY;   15/10/29
IMG_START_TIME:  29036.53 SOD {08:03:56.53} UT
FILTER:          10, White
BKG_MEAN:        0.474
N_STARS:         30
X_OFFSET:        168 [pixels]
Y_OFFSET:        396 [pixels]
X_MAX:           1607 [pixels]
Y_MAX:           1835 [pixels]
DET_THRESH:      6
PHOTO_THRESH:    3
SL_URL:          sw00662086000msufc467798636.fits
SUN_POSTN:       213.28d {+14h 13m 08s}  -13.38d {-13d 22' 54"}
SUN_DIST:        131.05 [deg]   Sun_angle= 11.6 [hr] (West of Sun)
MOON_POSTN:       59.76d {+03h 59m 02s}  +15.97d {+15d 58' 30"}
MOON_DIST:        55.03 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      239.93,-66.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       20.29,-47.15 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 29 Oct 15 08:12:59 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     662086,   Seg_Num: 0
POINT_RA:         38.537d {+02h 34m 09s} (J2000)
POINT_DEC:       -35.367d {-35d 22' 00"} (J2000)
POINT_ROLL:      173.223d
IMG_START_DATE:  17324 TJD;   302 DOY;   15/10/29
IMG_START_TIME:  29036.53 SOD {08:03:56.53} UT
FILTER:          10, White
BKG_MEAN:        0.474
N_STARS:         30
X_OFFSET:        168 [pixels]
Y_OFFSET:        396 [pixels]
X_MAX:           1607 [pixels]
Y_MAX:           1835 [pixels]
DET_THRESH:      6
PHOTO_THRESH:    3
SL_URL:          sw00662086000msufc467798636.fits
SUN_POSTN:       213.28d {+14h 13m 08s}  -13.38d {-13d 22' 54"}
SUN_DIST:        131.05 [deg]   Sun_angle= 11.6 [hr] (West of Sun)
MOON_POSTN:       59.76d {+03h 59m 03s}  +15.98d {+15d 58' 32"}
MOON_DIST:        55.03 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      239.93,-66.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       20.29,-47.15 [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 29 Oct 15 08:13:16 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     662086,   Seg_Num: 0
POINT_RA:         38.535d {+02h 34m 08s} (J2000)
POINT_DEC:       -35.365d {-35d 21' 53"} (J2000)
ROLL:            173.225d
IMG_START_DATE:  17324 TJD;   302 DOY;   15/10/29
IMG_START_TIME:  28270.93 SOD {07:51:10.93} UT
FILTER:          10, White
EXPOSURE_ID:     467797886
X_OFFSET:        727 [pixels]
Y_OFFSET:        955 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       887
Y_GRB_POS:       1115
BINNING_INDEX:   1
IM_URL:          sw00662086000msuni467797886.fits
SUN_POSTN:       213.28d {+14h 13m 08s}  -13.38d {-13d 22' 54"}
SUN_DIST:        131.05 [deg]   Sun_angle= 11.6 [hr] (West of Sun)
MOON_POSTN:       59.77d {+03h 59m 04s}  +15.98d {+15d 58' 34"}
MOON_DIST:        55.03 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      239.93,-66.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       20.29,-47.15 [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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 29 Oct 15 08:24:51 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     662086,   Seg_Num: 0
GRB_RA:           38.5279d {+02h 34m 06.69s} (J2000),
                  38.6917d {+02h 34m 45.99s} (current),
                  38.0104d {+02h 32m 02.48s} (1950)
GRB_DEC:         -35.3855d {-35d 23' 07.8"} (J2000),
                 -35.3167d {-35d 18' 59.9"} (current),
                 -35.6041d {-35d 36' 14.6"} (1950)
GRB_ERROR:       2.3 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17324 TJD;   302 DOY;   15/10/29
IMG_START_TIME:  28285.00 SOD {07:51:25.00} UT
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       213.29d {+14h 13m 10s}  -13.38d {-13d 23' 04"}
SUN_DIST:        131.03 [deg]   Sun_angle= 11.6 [hr] (West of Sun)
MOON_POSTN:       59.89d {+03h 59m 33s}  +15.99d {+15d 59' 40"}
MOON_DIST:        55.11 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      239.98,-66.64 [deg] galactic lon,lat of the burst
ECL_COORDS:       20.27,-47.16 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        This position was enhanced using UVOT field astrometry.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.

GCN Circular #18522
T. N. Ukwatta (LANL), A. D'Ai (INAF-IASFPA), J. A. Kennea (PSU), A. Maselli (INAF-IASFPA), P. T. O'Brien (U Leicester) and D. M. Palmer (LANL) report on behalf of the Swift Team:
At 07:49:54 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 151029A (trigger=662086). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 38.529, -35.354, which is
```
   RA(J2000)  =  02h 34m 07s
   Dec(J2000) = -35d 21' 14.4"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Lightcurve data is not immediately available.
Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 38.5280, -35.3855 which is equivalent to:
```
   RA(J2000)  = 02h 34m 06.72s
   Dec(J2000) = -35d 23' 07.7"
```
with an uncertainty of 2.3 arcseconds (radius, 90% containment). This position is 113.4 arcsec from the BAT position. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. We cannot determine whether the source is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 3.41 x 10^20 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 209 seconds after the BAT trigger. The initial 2.7'x2.7' sub-image does not cover the XRT error circle. There is a candidate afterglow in the UVOT srclist at:
```
RA(J2000) =   02:34:08.08 = 38.527964
DEC(J2000) = +35:23:08.8 = -35.385784
```
with a 90%-confidence error radius of about 0.61 arc sec. This position is 1.06 arc sec. from the center of the XRT error circle. The estimated magnitude is 17.34 with a 1-sigma error of about 0.04. No correction has been made for the expected extinction.
Burst Advocate for this burst is T. N. Ukwatta (tilan.ukwatta AT gmail.com). 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 Circular #18523
F. Knust, J. Bolmer, T. Kruehler (all MPE Garching), S. Schmidl (TLS Tautenburg) and J. Greiner (MPE Garching) report:
We observed the field of GRB 151029A (Swift trigger 662086, Ukwatta et al., GCN 18522) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPG telescope at ESO La Silla Observatory (Chile).
Observations started at October 29, 2015, 08:33, about 40 minutes after the GRB trigger. Inside the X-ray error (Ukwatta et al., GCN 18522) circle we detect the UVOT counterparts at coordinates
```
RA: 02:34:06.75
Decl: -35:23:08.6
```
with an error of around 0".5.
At a mean time of October 29, 2015, 08:37 UTC, we measure the following preliminary AB magnitudes and upper limits of:
```
g' = 19.9 +- 0.1
r' = 19.7 +- 0.1
i' = 19.7 +- 0.1
z' = 19.7 +- 0.1
J = 19.5 +- 0.2
H > 19.4
K > 19.4
```
Magnitudes and upper limts are calibrated against GROND zeropoints and 2MASS field stars and are not corrected for the Galactic extinction corresponding to a reddening of E_B-V = 0.018 mag (Schlafly & Finkbeiner 2011) in the direction of the burst.
GCN Circular #18524
Nial R. Tanvir (Univ. Leicester), Thomas Kruehler (MPE), Daniele Malesani (DARK/NBI), Dong Xu (NAOC/CAS), Antonio de Ugarte Postigo (IAA-CSIC), Giovanna Pugliese (API/UvA) report on behalf of a larger collaboration:
We observed the optical counterpart of GRB 151029A (Ukwatta et al., GCN 18522; Knust et al., GCN 18523) using the ESO Very Large Telescope UT2 equipped with the X-shooter spectrograph. Observations started on Oct 29.369 UT (1.02 hr after the GRB), that is at the end of the Chilean night, and were extended over twilight.
The optical counterpart (Ukwatta et al., GCN 18522; Knust et al., GCN 18523) is clearly detected in our grz acquisition images.
We detect a faint continuum throughout the spectral range of our observations, from about 3300A to 18000A, indicating an upper limit to the redshift of z~2. We also detect several weak absorption features that would be consistent with being MgII (2796/2804) and FeII (2344/2587/2600) lines at z=1.423, which we therefore report as the likely redshift for this GRB.
We acknowledge expert support from the ESO observing staff, in particular Thomas Rivinius and Marcela Espinoza.
GCN Circular #18526
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team.
Using 789 s of XRT Photon Counting mode data and 2 UVOT images for GRB 151029A, 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 = 38.52779, -35.38553 which is equivalent to:
```
RA (J2000): 02h 34m 6.67s
Dec (J2000): -35d 23' 07.9"
```
with an uncertainty of 2.0 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #18527
M. Stamatikos (OSU), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-60 to T+243 sec from the recent telemetry downlink, we report further analysis of BAT GRB 151029A (trigger #662086) (Ukwatta, et al., GCN Circ. 18522). The BAT ground-calculated position is RA, Dec = 38.537, -35.356 deg, which is
```
   RA(J2000)  =  02h 34m 09.0s 
   Dec(J2000) = -35d 21' 21.7" 
```
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 41%.
The mask-weighted light curve shows two overlapping peaks starting at ~T-2 sec, peaking at ~T+1 se, and ending at ~T+10 sec. T90 (15-350 keV) is 8.95 +- 2.32 sec (estimated error including systematics).
The time-averaged spectrum from T-1.10 to T+10.47 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.49 +- 1.08, and Epeak of 33.9 +- 6.9 keV (chi squared 53.8 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 3.9 +- 0.6 x 10^-7 erg/cm2 and the 1-sec peak flux measured from T-0.15 sec in the 15-150 keV band is 1.8 +- 0.3 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.16 +- 0.19 (chi squared 64.3 for 57 d.o.f.). 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/662086/BA/
GCN Circular #18530
S. Dichiara (U. Ferrara, ICRANet), C. Guidorzi (U. Ferrara), S. Kobayashi (LJMU), A. Gomboc (U. Ljubljana) on behalf of a larger collaboration report:
The 2-m LCOGT Faulkes Telescope South began observing Swift GRB 151029A (Ukwatta et al. GCN 18522) on October 29, 09:33 UT (1.7 hours after the burst trigger) with SDSS R and I filters. We marginally detect the optical afterglow (Ukwatta et al. GCN 18522; Knust et al. GCN 18523; Tanvir et al. GCN 18524) due to poor sky conditions with the following magnitudes:
```
Mid Time      Exposure       Filter       Magnitude
(hours)           (s)
-------------------------------------------------------
1.8            5x120         R           20.6 +- 0.4
2.0            5x120         I           21.0 +- 0.5
-------------------------------------------------------
```
Calibration is done against nearby USNOB-1 star RA(J2000)=02:34:10.069, DEC(J2000)=-35:24:13.54, assuming R2=16.95 mag and I=17.63 mag.
GCN Circular #18531
S. R. Oates (IAA-CSIC/UCL-MSSL) and T. N. Ukwatta (LANL) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 151029A 92 s after the BAT trigger (Ukwatta et al., GCN Circ. 18522). A source consistent with the XRT position (Beardmore et al., GCN Circ. 18526) is detected in the initial UVOT exposures.
The preliminary UVOT position is:
```
  RA  (J2000) =  02:34:06.72 =  38.52799 (deg.)
  Dec (J2000) = -35:23:08.6  = -35.38573 (deg.)
```
with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence).
Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white               92          242          147         16.98 +/- 0.03
v                  634          653           19         17.66 +/- 0.32
b                  560          752           39         19.24 +/- 0.33
u                  304          554          246         17.35 +/- 0.06
w1                 683          703           19        >17.98
m2                 658          850           39        >18.17
w2                 609          802           39        >18.64
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #18532
A. D'ai (INAF-IASFPA), A. Maselli (INAF-IASFPA), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), S.L. Gibson (U. Leicester), A. Melandri (INAF-OAB) and T.N. Ukwatta report on behalf of the Swift-XRT team:
We have analysed 15 ks of XRT data for GRB 151029A (Ukwatta et al. GCN Circ. 18522), from 106 s to 35.4 ks after the BAT trigger. The data comprise 23 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN Circ. 18526).
The light curve can be modelled with a power-law decay with a decay index of alpha=1.08 (+/-0.06).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.30 (+0.31, -0.29). The best-fitting absorption column is 3.0 (+3.7, -3.0) x 10^21 cm^-2, at a redshift of 1.423, in addition to the Galactic value of 3.4 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 2.9 x 10^-11 (3.6 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Galactic foreground: 3.4 x 10^20 cm^-2
Intrinsic column:    3.0 (+3.7, -3.0) x 10^21 cm^-2 at z=1.423
Photon index:	     2.30 (+0.31, -0.29)
```
If the light curve continues to decay with a power-law decay index of 1.08, the count rate at T+24 hours will be 8.0 x 10^-4 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.3 x 10^-14 (2.9 x 10^-14) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00662086.
This circular is an official product of the Swift-XRT team.
GCN Circular #18534
D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe (IAO, NAOJ), K. Yanagisawa (OAO, NAOJ), S.Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of the MITSuME and OISTER collaboration:
We observed the field of GRB 151029A (Ukwatta et al., GCNC 18522) with the optical three color (g', Rc and Ic) CCD camera attached to the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory.
The observation started on 2015-10-29 14:56:55 UT (~6.5h after the burst). We could not detect the previously reported afterglow (Ukwatta et al., GCNC 18522; Knust et al., GCNC 18523; Tanvir et al., GCNC 18524) in all the three bands.
Three sigma upper limits of the OT are listed below. We used GSC2.3 catalog for flux calibration.
```
#T0+[day]  MID-UT    T-EXP[sec]   g'     Rc     Ic
-----------------------------------------------------
0.31392    15:56:55    5760.0   >20.5  >20.7  >19.8
-----------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
```
GCN Circular #18535
S. Barthelmy and F. Marshall (GSFC) on behalf of the Swift team:
In GCN Circular 18522, we stated that the trigger time for GRB 151029A was 07:49:54 UT, but with the full data set downlinked, the correct trigger time is 07:49:39 UT. The correction for the on-board clock drift had not been applied in the original Circular due to the lack of some of the real-time TDRSS downlinked data. We apologise for any inconvenience.
GCN Circular #18554
Martin Jelinek (Astronomical Institute ASU-AVCR Ondrejov), Michael Prouza, Jan Ebr, Petr Janecek, Martin Masek (Institute of Physics FZU-CAS Praha) and Samantha Oates (IAA CSIC Granada + UCL MSSL)
"The 0.30m robotic telescope FRAM located in Malargue, Argentina, observed the reported location of GRB 151029A (Ukwatta GCNC 18522) starting 884s after the corrected trigger time (Barthelmy GCNC 18535), 8.9s after receiving the trigger.
The telescope obtained a 30 minute set of unfiltered exposures. The optical afterglow (Oates GCNC 18531, Knust GCNC 18523, Tanvir GCNC 18524) can be detected on combined exposures.
In the first combined image, with the mean time of individual exposures 08:07:27 UT (1068s post trigger), we measure magnitude 17.7 +/- 0.2. The calibration was done with three nearby USNO-B2.0 stars."

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Jochen Greiner, last update: 03-Nov-2015 [Disclaimer]