Gamma-ray Burst 151112A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 12 Nov 15 13:45:01 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     663179,   Seg_Num: 0
GRB_RA:            2.045d {+00h 08m 11s} (J2000),
                   2.242d {+00h 08m 58s} (current),
                   1.420d {+00h 05m 41s} (1950)
GRB_DEC:         -61.692d {-61d 41' 32"} (J2000),
                 -61.604d {-61d 36' 14"} (current),
                 -61.971d {-61d 58' 13"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       2094 [cnts]    Image_Peak=125 [image_cnts]
TRIGGER_DUR:     0.512 [sec] 
TRIGGER_INDEX:   41     E_range: 25-100 keV
BKG_INTEN:       24517 [cnts]
BKG_TIME:        49472.59 SOD {13:44:32.59} UT
BKG_DUR:         8 [sec]
GRB_DATE:        17338 TJD;   316 DOY;   15/11/12
GRB_TIME:        49488.08 SOD {13:44:48.08} UT
GRB_PHI:         -38.28 [deg]
GRB_THETA:        35.96 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     12.48 [sigma]
IMAGE_SIGNIF:    8.08 [sigma]
MERIT_PARAMS:     +1  +0  +0  -1  +2  -2  +0  +0  +5  +0 
SUN_POSTN:       227.40d {+15h 09m 36s}  -17.70d {-17d 41' 53"}
SUN_DIST:         92.98 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:      238.15d {+15h 52m 36s}  -15.77d {-15d 46' 10"}
MOON_DIST:        91.00 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      311.79,-54.69 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      324.77,-54.54 [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 = 245.32,-20.08 [deg].

red DSS finding chart ps-file

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 12 Nov 15 13:51:47 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     9085451,   Seg_Num: 6
GRB_RA:            2.045d {+00h 08m 11s} (J2000),
                   2.242d {+00h 08m 58s} (current),
                   1.420d {+00h 05m 41s} (1950)
GRB_DEC:         -61.692d {-61d 41' 32"} (J2000),
                 -61.604d {-61d 36' 14"} (current),
                 -61.971d {-61d 58' 13"} (1950)
GRB_DATE:        17338 TJD;   316 DOY;   15/11/12
GRB_TIME:        49488.08 SOD {13:44:48.08} UT
TRIGGER_INDEX:   41
GRB_PHI:         -38.28 [deg]
GRB_THETA:        35.96 [deg]
DELTA_TIME:      -6410.00 [sec]
TRIGGER_DUR:     0.512 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    0.00 [sigma]
LC_URL:          sw00663179000msb.lc
SUN_POSTN:       227.41d {+15h 09m 37s}  -17.70d {-17d 41' 57"}
SUN_DIST:         92.98 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:      238.21d {+15h 52m 51s}  -15.78d {-15d 46' 44"}
MOON_DIST:        90.97 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      311.79,-54.69 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      324.77,-54.54 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Lightcurve.  
COMMENTS:           
COMMENTS:        WARNING: No BAT_Position TDRSS message was received for this trigger_number!  
COMMENTS:           
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 = 245.32,-20.08 [deg].  
COMMENTS:        The 3rd packet (of 3) was missing in the lightcurve data stream.

GCN NOTICE

 
TITLE:           GCN/MAXI NOTICE
NOTICE_DATE:     Thu 12 Nov 15 14:08:15 UT
NOTICE_TYPE:     MAXI Unknown Source Position
EVENT_ID_NUM:    338494614
EVENT_RA:          2.18d {+00h 08m 43s} (J2000),
                   2.38d {+00h 09m 31s} (current),
                   1.56d {+00h 06m 14s} (1950)
EVENT_DEC:       -61.67d {-61d 40' 07"} (J2000),
                 -61.58d {-61d 34' 49"} (current),
                 -61.95d {-61d 56' 49"} (1950)
EVENT_ERROR:     1.0 [deg radius, stat+sys, 90% containment]
EVENT_FLUX:      514.0 +- 0.0 [mCrab]
EVENT_DATE:      17338 TJD;   316 DOY;   15/11/12
EVENT_TIME:      49523.00 SOD {13:45:23.00} UT
EVENT_TSCALE:    3s
EVENT_EBAND:     Low, 2-4 keV
SUN_POSTN:       227.42d {+15h 09m 40s}  -17.70d {-17d 42' 08"}
SUN_DIST:         93.03 [deg]
MOON_POSTN:      238.36d {+15h 53m 25s}  -15.80d {-15d 48' 07"}
MOON_DIST:        90.96 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      311.69,-54.73 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      324.88,-54.56 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        MAXI Unknown Source Position. GRB or unknown X-ray Transient.

GCN Circular #18588
D. Malesani (DARK/NBI), S. D. Barthelmy (GSFC), P. A. Evans (U Leicester), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (UCL-MSSL), K. L. Page (U Leicester), T. G. R. Roegiers (PSU) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team:
At 13:44:48 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 151112A (trigger=663179). Swift did not slew immediately to the burst. The BAT on-board calculated location is RA, Dec 2.045, -61.692 which is
```
   RA(J2000) = 00h 08m 11s
   Dec(J2000) = -61d 41' 32"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a FRED-shaped profile with superimposed peaks and total duration of about 20 sec. The peak count rate was ~2000 counts/sec (15-350 keV), at ~0 sec after the trigger.
Due to an observing constraint, Swift will not slew until T0+50.8 minutes. There will be no XRT or UVOT data until this time.
Burst Advocate for this burst is D. Malesani (malesani AT dark-cosmology.dk). 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:     Thu 12 Nov 15 14:37:21 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     663179,   Seg_Num: 0
POINT_RA:          2.066d {+00h 08m 16s} (J2000)
POINT_DEC:       -61.679d {-61d 40' 43"} (J2000)
IMG_START_DATE:  17338 TJD;   316 DOY;   15/11/12
IMG_START_TIME:  52629.12 SOD {14:37:09.12} UT,   3141.0 [sec] since BAT Trigger Time
COUNTS:          1    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        0    Max_iter_allowed= 4
ERROR_CODE:      1
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        No source found in the image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 12 Nov 15 14:40:04 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     663179,   Seg_Num: 0
POINT_RA:          2.066d {+00h 08m 16s} (J2000)
POINT_DEC:       -61.679d {-61d 40' 42"} (J2000)
POINT_ROLL:      222.756d
IMG_START_DATE:  17338 TJD;   316 DOY;   15/11/12
IMG_START_TIME:  52632.46 SOD {14:37:12.46} UT,   3144.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.624
N_STARS:         82
X_OFFSET:        578 [pixels]
Y_OFFSET:        460 [pixels]
X_MAX:           1537 [pixels]
Y_MAX:           1419 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00663179000msufc3144.fits
SUN_POSTN:       227.44d {+15h 09m 45s}  -17.71d {-17d 42' 30"}
SUN_DIST:         92.98 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:      238.64d {+15h 54m 33s}  -15.85d {-15d 50' 46"}
MOON_DIST:        90.76 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      311.78,-54.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      324.80,-54.53 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 12 Nov 15 14:40:37 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     663179,   Seg_Num: 0
POINT_RA:          2.066d {+00h 08m 16s} (J2000)
POINT_DEC:       -61.679d {-61d 40' 42"} (J2000)
POINT_ROLL:      222.756d
IMG_START_DATE:  17338 TJD;   316 DOY;   15/11/12
IMG_START_TIME:  52632.46 SOD {14:37:12.46} UT,   3144.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.624
N_STARS:         82
X_OFFSET:        578 [pixels]
Y_OFFSET:        460 [pixels]
X_MAX:           1537 [pixels]
Y_MAX:           1419 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00663179000msufc3144.fits
SUN_POSTN:       227.44d {+15h 09m 46s}  -17.71d {-17d 42' 30"}
SUN_DIST:         92.98 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:      238.64d {+15h 54m 34s}  -15.85d {-15d 50' 49"}
MOON_DIST:        90.76 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      311.78,-54.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      324.80,-54.53 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 12 Nov 15 14:41:03 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     663179,   Seg_Num: 0
GRB_RA:            2.0569d {+00h 08m 13.65s} (J2000),
                   2.2540d {+00h 09m 00.96s} (current),
                   1.4322d {+00h 05m 43.72s} (1950)
GRB_DEC:         -61.6629d {-61d 39' 46.4"} (J2000),
                 -61.5746d {-61d 34' 28.7"} (current),
                 -61.9412d {-61d 56' 28.2"} (1950)
GRB_ERROR:       4.2 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17338 TJD;   316 DOY;   15/11/12
IMG_START_TIME:  52649.00 SOD {14:37:29.00} UT,   3160.9 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       227.44d {+15h 09m 46s}  -17.71d {-17d 42' 31"}
SUN_DIST:         92.99 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:      238.64d {+15h 54m 35s}  -15.85d {-15d 50' 51"}
MOON_DIST:        90.76 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      311.79,-54.72 [deg] galactic lon,lat of the burst
ECL_COORDS:      324.81,-54.52 [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:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 12 Nov 15 14:41:35 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     663179,   Seg_Num: 0
POINT_RA:          2.066d {+00h 08m 16s} (J2000)
POINT_DEC:       -61.679d {-61d 40' 42"} (J2000)
ROLL:            222.756d
IMG_START_DATE:  17338 TJD;   316 DOY;   15/11/12
IMG_START_TIME:  52632.46 SOD {14:37:12.46} UT,   3144.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     469031847
X_OFFSET:        897 [pixels]
Y_OFFSET:        779 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1057
Y_GRB_POS:       939
BINNING_INDEX:   1
IM_URL:          sw00663179000msuni3160.fits
SUN_POSTN:       227.44d {+15h 09m 46s}  -17.71d {-17d 42' 31"}
SUN_DIST:         92.98 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:      238.65d {+15h 54m 36s}  -15.85d {-15d 50' 54"}
MOON_DIST:        90.75 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      311.78,-54.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      324.80,-54.53 [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 12 Nov 15 14:41:46 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     663179,   Seg_Num: 0
POINT_RA:          2.066d {+00h 08m 16s} (J2000)
POINT_DEC:       -61.679d {-61d 40' 42"} (J2000)
ROLL:            222.756d
IMG_START_DATE:  17338 TJD;   316 DOY;   15/11/12
IMG_START_TIME:  52632.46 SOD {14:37:12.46} UT,   3144.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     469031847
X_OFFSET:        897 [pixels]
Y_OFFSET:        779 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1057
Y_GRB_POS:       939
BINNING_INDEX:   1
IM_URL:          sw00663179000msuni3160.fits
SUN_POSTN:       227.44d {+15h 09m 46s}  -17.71d {-17d 42' 31"}
SUN_DIST:         92.98 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:      238.65d {+15h 54m 36s}  -15.85d {-15d 50' 55"}
MOON_DIST:        90.75 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      311.78,-54.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      324.80,-54.53 [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 #18589
D.N. Burrows (PSU), J.A. Kennea (PSU), M. Perri (ASDC), G. Tagliaferri (INAF-OAB), P.A. Evans (U. Leicester) and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team:
The XRT began observing the field of GRB 151112A at 14:37:09.1 UT, 3141.0 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 2.05651, -61.66273 which is equivalent to:
```
   RA(J2000)  = 00h 08m 13.56s
   Dec(J2000) = -61d 39' 45.8"
```
with an uncertainty of 3.6 arcseconds (radius, 90% containment). This location is 107 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (1.92 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 3 (+2.37/-2.09) x 10^21 cm^-2 (90% confidence).
GCN Circular #18590
S. R. Oates (IAA-CSIC, UCL-MSSL) reports on behalf of the UVOT team:
UVOT took a finding chart exposure of GRB 151112A, 150 seconds with the White filter starting 3144 seconds after the BAT trigger (Malesani et al., GCN Circ. 18588). No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers none of the XRT error circle (Burrows et al., GCN Circ. 18589). The 8'x8' region for the list of sources generated on-board covers 100% of th e XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.01.
GCN Circular #18591
D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory
E. Gorbovskoy, V. Lipunov, V.Shumkov, N.Tyurina, V.Kornilov, P.Balanutsa, A.Kuznetsov, D. Vlasenko Lomonosov Moscow State University, Sternberg Astronomical Institute
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias
A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Senik Kislovodsk Solar Station of the Pulkovo Observatory
O.Gress, K.Ivanov, N.M.Budnev, V.A.Poleshchuk Irkutsk State University
V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk
V.Krushinski, I.Zalozhnih Ural Federal University, Kourovka
Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA)
MASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in SAAO was pointed to the GRB151112A at 2015-11-12 18:12:09 UT (~5.5 hours ater trigger). On our first (180s exposure) set we did not find optical transient within Swift error-box (Malesani et al., GCN #18588; Burrows et al., GCN #18589; ) brighter then 20.5.
The message may be cited.
GCN Circular #18592
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 4055 s of XRT Photon Counting mode data and 6 UVOT images for GRB 151112A, 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 = 2.05348, -61.66328 which is equivalent to:
```
RA (J2000): 00h 08m 12.84s
Dec (J2000): -61d 39' 47.8"
```
with an uncertainty of 1.4 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 #18593
H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), A. Y. Lien (GSFC/UMBC), D. Malesani (DARK/NBI), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), 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 151112A (trigger #663179) (Malesani, et al., GCN Circ. 18588). The BAT ground-calculated position is RA, Dec = 2.050, -61.680 deg which is
```
    RA(J2000)  =  00h 08m 11.9s
    Dec(J2000) = -61d 40' 46.7"
```
with an uncertainty of 2.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 52%.
The mask-weighted light curve shows several overlapping peaks, starting with a sharp rise peaking at T=0 sec, then a second peak at T+5 sec, a third at T+10 sec and falling to background by T+20 sec. T90 (15-350 keV) is 19.32 +- 31.24 sec (estimated error including systematics).
The time-averaged spectrum from T-0.06 to T+61.94 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.77 +- 0.21. The fluence in the 15-150 keV band is 9.4 +- 1.2 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T-0.01 sec in the 15-150 keV band is 1.9 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/663179/BA/
GCN Circular #18594
T.G.R. Roegiers (PSU), L.M. McCauley (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. D'ai (INAF-IASFPA), J.A. Kennea (PSU) and D. Malesani report on behalf of the Swift-XRT team:
We have analysed 9.6 ks of XRT data for GRB 151112A (Malesani et al. GCN Circ. 18588), from 3.1 ks to 33.0 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN Circ. 18592).
The light curve can be modelled with a power-law decay with a decay index of alpha=0.43 (+/-0.08).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.21 (+0.17, -0.16). The best-fitting absorption column is 1.1 (+/-0.4) x 10^21 cm^-2, in excess of the Galactic value of 1.9 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 3.0 x 10^-11 (4.0 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     1.1 (+/-0.4) x 10^21 cm^-2
Galactic foreground: 1.9 x 10^20 cm^-2
Excess significance: 4.1 sigma
Photon index:	     2.21 (+0.17, -0.16)
```
If the light curve continues to decay with a power-law decay index of 0.43, the count rate at T+24 hours will be 0.040 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 x 10^-12 (1.6 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00663179.
This circular is an official product of the Swift-XRT team.
GCN Circular #18595
F. Knust, T.-W. Chen and J. Greiner (all MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 151112A (Swift trigger 663179; Malesani et al., GCN #18588) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at the ESO La Silla Observatory (Chile).
Observations started at 00:09 UT on 2015-11-13, 10.5hrs after the GRB trigger, and are continuing. They were performed at an average seeing of 1.8" and at an average airmass of 1.2.
We found a single point source within the 1.4" Swift-XRT error circle reported by Osborne et al. (GCN #18592) at
```
RA (J2000.0) = 00h 08m 12.77s
DEC (J2000.0) = -61d 39' 48.4"
```
with an uncertainty of 0.5" in each coordinate.
Based on 11.50 min of total exposures in g'r'i'z' and 12.00 min in JHK, we estimate preliminary magnitudes (all in AB system) of
```
g' > 23.9 mag,
r' = 23.9 +/- 0.373 mag,
i' = 22.4 +/- 0.169 mag,
z' = 22.5 +/- 0.288 mag,
J  > 21.0 mag,
H  > 20.5 mag, and
K  > 19.0 mag.
```
Given magnitudes are calibrated against GROND zeropoints as well as 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.01 mag in the direction of the burst (Schlegel et al. 1998).
GCN Circular #18596
K. Yamaoka (Nagoya U.), H. Negoro, T. Masumitsu (Nihon U.), S. Ueno, H. Tomida, S. Nakahira, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Serino, M. Shidatsu, J. Sugimoto, T. Takagi, M. Matsuoka (RIKEN), N. Kawai, T. Yoshii, Y. Tachibana (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, R. Imatani (Osaka U.), M. Nakajima, K. Tanaka (Nihon U.), Y. Ueda, T. Kawamuro, T. Hori (Kyoto U.), Y. Tsuboi, S. Kanetou (Chuo U.), M. Yamauchi, D. Itoh (Miyazaki U.), K. Yamaoka (Nagoya U.), M. Morii (ISM), report on behalf of the MAXI team:
The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 13:45:24 UT. Assuming that the source flux was constant over the transit, we obtain the source position at
(R.A., Dec) = (1.543 deg, -61.934 deg) = (00 06 10, -61 56 03) (J2000)
with a 90% C.L. statistical error of 0.25 deg and an additional systematic uncertainty of 0.1 deg (90% containment radius). This position is consistent with Swift GRB 151112A (Malesani et al., GCN Circ. 18588). The X-ray flux averaged over the scan was 217 +- 31 mCrab (4-10keV, 1 sigma error). There was no significant excess flux in the previous transit at 12:12 UT and in the next transit at 2015-11-12 15:17 UT with an upper limit of 20 mCrab for each.
GCN Circular #18597
S. R. Oates (IAA-CSIC/UCL-MSSL) and D. Malesani (DARK/NBI) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 151112A 3144 s after the BAT trigger (Malesani et al., GCN Circ. 18588). No optical afterglow, consistent with the enhanced XRT position (Osborne et al. GCN Circ. 18592) and the GROND position (Knust et al., GCN Circ. 18595), is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC          3144         3294          147         >21.3
white             3144         4527          344         >21.8
v                 3301         4938          393         >20.2
b                 4123        10985          349         >21.1
u                 3917        10825         1082         >21.5
w1                3711         9912         1169         >21.4
m2                3506        15760         1240         >21.3
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #18603
J. Bolmer, F. Knust and J. Greiner (all MPE Garching) report on behalf of the GROND team:
We present further analysis of the GROND observations of GRB 151112A (Swift trigger 663179; Malesani et al., GCN #18588; Knust et al. GCN #18595).
After correcting for the galactic foreground E(B-V)=0.01 mag and fitting a power-law model to the 7-channel GROND SED from the first night, we derive a photometric redshift of z = 4.1 +/- 0.3, according to the g'- and r'-band dropouts with g'-r' > 1.5 mag and r'-i' = 0.9 mag.
Based on the observed decay between the first and the second night we predict an i'-band magnitude of ~24 mag for the coming night.

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Jochen Greiner, last update: 14-Nov-2015 [Disclaimer]