Gamma-ray Burst 151004A

(All information courtesy of the instrument teams.)

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 04 Oct 15 18:10:31 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     657564,   Seg_Num: 0
GRB_RA:          213.585d {+14h 14m 20s} (J2000),
                 213.891d {+14h 15m 34s} (current),
                 212.621d {+14h 10m 29s} (1950)
GRB_DEC:         -64.947d {-64d 56' 49"} (J2000),
                 -65.020d {-65d 01' 12"} (current),
                 -64.714d {-64d 42' 50"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       0 [cnts]    Image_Peak=1615 [image_cnts]
TRIGGER_DUR:     72.000 [sec] 
TRIGGER_INDEX:   20000     E_range: 15-50 keV
BKG_INTEN:       0 [cnts]
BKG_TIME:        0.00 SOD {00:00:00.00} UT
BKG_DUR:         0 [sec]
GRB_DATE:        17299 TJD;   277 DOY;   15/10/04
GRB_TIME:        65344.77 SOD {18:09:04.77} UT
GRB_PHI:         -166.31 [deg]
GRB_THETA:        16.04 [deg]
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    8.34 [sigma]
MERIT_PARAMS:     +1  +0  +0  +6  +1  -1  +0  +1 -45  +0 
SUN_POSTN:       190.30d {+12h 41m 11s}   -4.43d {-04d 25' 49"}
SUN_DIST:         62.88 [deg]   Sun_angle= -1.6 [hr] (East of Sun)
MOON_POSTN:      100.27d {+06h 41m 06s}  +17.82d {+17d 49' 24"}
MOON_DIST:       116.01 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:      311.57, -3.47 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      238.48,-47.56 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is an image trigger.  (The RATE_SIGNIF & BKG_{INTEN, TIME, DUR} are undefined.)  
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 = 314.19,20.49 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 04 Oct 15 18:13:12 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     657564,   Seg_Num: 0
GRB_RA:          213.585d {+14h 14m 20s} (J2000),
                 213.891d {+14h 15m 34s} (current),
                 212.621d {+14h 10m 29s} (1950)
GRB_DEC:         -64.947d {-64d 56' 49"} (J2000),
                 -65.020d {-65d 01' 12"} (current),
                 -64.714d {-64d 42' 50"} (1950)
GRB_DATE:        17299 TJD;   277 DOY;   15/10/04
GRB_TIME:        65344.77 SOD {18:09:04.77} UT
TRIGGER_INDEX:   20000
GRB_PHI:         -166.31 [deg]
GRB_THETA:        16.04 [deg]
DELTA_TIME:      0.00 [sec]
TRIGGER_DUR:     72.000 [sec] 
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    8.34 [sigma]
LC_URL:          sw00657564000msb.lc
SUN_POSTN:       190.30d {+12h 41m 12s}   -4.43d {-04d 25' 51"}
SUN_DIST:         62.88 [deg]   Sun_angle= -1.6 [hr] (East of Sun)
MOON_POSTN:      100.30d {+06h 41m 12s}  +17.82d {+17d 49' 18"}
MOON_DIST:       116.00 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:      311.57, -3.47 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      238.48,-47.56 [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 an image 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 = 314.19,20.49 [deg].

GCN Circular #18389
S. B. Cenko (GSFC), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU), E. Troja (NASA/GSFC/UMCP) and T. N. Ukwatta (LANL) report on behalf of the Swift Team:
At 18:09:04 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 151004A (trigger=657564). Swift did not slew due to the Earth-limb observing constraint. The BAT on-board calculated location is RA, Dec 213.585, -64.947, which is
```
   RA(J2000)  =  14h 14m 20s   
   Dec(J2000) = -64d 56' 49"   
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for image triggers, the real-time light curve does not show anything significant.
Due to an observing constraint, Swift will not slew until T0+56.9 minutes. There will be no XRT or UVOT data until this time.
Burst Advocate for this burst is S. B. Cenko (brad.cenko AT 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:     Sun 04 Oct 15 19:09:21 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     657564,   Seg_Num: 0
POINT_RA:        213.609d {+14h 14m 26s} (J2000)
POINT_DEC:       -64.906d {-64d 54' 22"} (J2000)
IMG_START_DATE:  17299 TJD;   277 DOY;   15/10/04
IMG_START_TIME:  68954.04 SOD {19:09:14.04} UT,   3609.3 [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:     Sun 04 Oct 15 19:14:33 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     657564,   Seg_Num: 0
POINT_RA:        213.607d {+14h 14m 26s} (J2000)
POINT_DEC:       -64.906d {-64d 54' 22"} (J2000)
POINT_ROLL:      333.775d
IMG_START_DATE:  17299 TJD;   277 DOY;   15/10/04
IMG_START_TIME:  68957.61 SOD {19:09:17.61} UT,   3612.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        6.636
N_STARS:         190
X_OFFSET:        178 [pixels]
Y_OFFSET:        512 [pixels]
X_MAX:           1137 [pixels]
Y_MAX:           1471 [pixels]
DET_THRESH:      22
PHOTO_THRESH:    13
SL_URL:          sw00657564000msufc3612.fits
SUN_POSTN:       190.34d {+12h 41m 21s}   -4.45d {-04d 26' 51"}
SUN_DIST:         62.82 [deg]   Sun_angle= -1.6 [hr] (East of Sun)
MOON_POSTN:      100.88d {+06h 43m 31s}  +17.79d {+17d 47' 16"}
MOON_DIST:       115.75 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:      311.59, -3.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      238.47,-47.52 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 04 Oct 15 19:15:03 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     657564,   Seg_Num: 0
POINT_RA:        213.607d {+14h 14m 26s} (J2000)
POINT_DEC:       -64.906d {-64d 54' 22"} (J2000)
POINT_ROLL:      333.775d
IMG_START_DATE:  17299 TJD;   277 DOY;   15/10/04
IMG_START_TIME:  68957.61 SOD {19:09:17.61} UT,   3612.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        6.636
N_STARS:         190
X_OFFSET:        178 [pixels]
Y_OFFSET:        512 [pixels]
X_MAX:           1137 [pixels]
Y_MAX:           1471 [pixels]
DET_THRESH:      22
PHOTO_THRESH:    13
SL_URL:          sw00657564000msufc3612.fits
SUN_POSTN:       190.34d {+12h 41m 21s}   -4.45d {-04d 26' 51"}
SUN_DIST:         62.82 [deg]   Sun_angle= -1.6 [hr] (East of Sun)
MOON_POSTN:      100.88d {+06h 43m 32s}  +17.79d {+17d 47' 15"}
MOON_DIST:       115.75 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:      311.59, -3.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      238.47,-47.52 [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:     Sun 04 Oct 15 19:16:33 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     657564,   Seg_Num: 0
POINT_RA:        213.607d {+14h 14m 26s} (J2000)
POINT_DEC:       -64.906d {-64d 54' 22"} (J2000)
ROLL:            333.775d
IMG_START_DATE:  17299 TJD;   277 DOY;   15/10/04
IMG_START_TIME:  68957.61 SOD {19:09:17.61} UT,   3612.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     465678572
X_OFFSET:        497 [pixels]
Y_OFFSET:        831 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       657
Y_GRB_POS:       991
BINNING_INDEX:   1
IM_URL:          sw00657564000msuni3628.fits
SUN_POSTN:       190.34d {+12h 41m 21s}   -4.45d {-04d 26' 53"}
SUN_DIST:         62.82 [deg]   Sun_angle= -1.6 [hr] (East of Sun)
MOON_POSTN:      100.90d {+06h 43m 35s}  +17.79d {+17d 47' 12"}
MOON_DIST:       115.74 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:      311.59, -3.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      238.47,-47.52 [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:     Sun 04 Oct 15 19:16:52 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     657564,   Seg_Num: 0
POINT_RA:        213.607d {+14h 14m 26s} (J2000)
POINT_DEC:       -64.906d {-64d 54' 22"} (J2000)
ROLL:            333.775d
IMG_START_DATE:  17299 TJD;   277 DOY;   15/10/04
IMG_START_TIME:  68957.61 SOD {19:09:17.61} UT,   3612.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     465678572
X_OFFSET:        497 [pixels]
Y_OFFSET:        831 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       657
Y_GRB_POS:       991
BINNING_INDEX:   1
IM_URL:          sw00657564000msuni3628.fits
SUN_POSTN:       190.34d {+12h 41m 21s}   -4.45d {-04d 26' 53"}
SUN_DIST:         62.82 [deg]   Sun_angle= -1.6 [hr] (East of Sun)
MOON_POSTN:      100.90d {+06h 43m 36s}  +17.79d {+17d 47' 11"}
MOON_DIST:       115.74 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:      311.59, -3.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      238.47,-47.52 [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 #18391
C. Pagani (U. Leicester), P. A. Evans (U. Leicester) and S. B. Cenko (GSFC) report on behalf of the Swift-XRT Team:
The XRT began observing the field of the possible GRB 151004A (Swift trigger 657564, Cenko et al., GCN Circ. 18389) at 19:09:14.0 UT, 3609.3 seconds after the BAT trigger. No source was detected in 1.1 ks of promptly downlinked data, which covered 84% of the BAT error circle. We are waiting for the full dataset to detect and localise any possible XRT counterpart.
This circular is an official product of the Swift-XRT team.
GCN Circular #18393
V. Lipunov, E. Gorbovskoy, N.Tyurina, V.Kornilov, P.Balanutsa, A.Kuznetsov, D.Kuvshinov, Lomonosov Moscow State University, Sternberg Astronomical Institute
D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory
K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University
A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory
V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk
V.Krushinski, I.Zalozhnih, A. Popov 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 II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in SAAO was pointed to the probable GRB (Swift Trigger 657564) 24 sec after notice time and 108 sec after trigger time at 2015-10-04 18:10:55 UT. On our first (20s exposure) set we not found optical transient within SWIFT error-box (Cenko et. al GCN 18389) brighter then 16.0.
Analysis of highly complicated proximity to the Milky Way (Galactic latitude l=-3.5) and strong winds (speed=65 km/h)
The 5-sigma upper limit has been about 16.0 mag The message may be cited.
GCN Circular #18393
M. De Pasquale (UCL-MSSL) and S. B. Cenko (GSFC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of the trigger 657564 (possible GRB 151004A) 3613 s after the BAT trigger (Cenko et al., GCN Circ. 18389). No optical afterglow consistent with the BAT position 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          3613         3763          147         >20
white             3613         4994          344         >20.3
v                 3770         5404          393         >18.7
b                 4590         4789          197         >19.2
u                 4384         4584          197         >18.9
w1                4179         4379          197         >19.0
m2                3974         5565          350         >19.3
w2                5000         5200          197         >19.1
```
The magnitudes in the table are not corrected for the heavy Galactic extinction due to the reddening of E(B-V) = 1.03 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #18396
S. D. Barthelmy (GSFC), S. B. Cenko (GSFC), J. R. Cummings (GSFC/UMBC), P.A. Evans (U. Leicester), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), D. Malesani (DARK/NBI), C. B. Markwardt (GSFC), C. Pagani (U. Leicester), K. L. Page (U. Leicester), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), and T. N. Ukwatta (LANL) report on behalf of the Swift team:
Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT trigger 657564 (the probable GRB 151004A; Cenko et al., GCN Circ. 18389). The BAT ground-calculated position is RA, Dec = 213.613, -64.956 deg which is
```
  RA(J2000)  =  14h 14m 27.1s
  Dec(J2000) = -64d 57' 23.3"
```
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%.
The BAT mask-weighted light curve shows a weak complex structure that starts at ~T-10 s and ends at ~T+130 s. T90 (15-350 keV) is 128.40 +- 17.77 sec (estimated error including systematics).
The BAT time-averaged spectrum from T-13.63 to T+134.42 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.95 +- 0.23. The fluence in the 15-150 keV band is 1.0 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+50.86 sec in the 15-150 keV band is 0.4 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
In the BAT energy band, the spectral properties and T90 are consistent with those of a GRB. However, due to the low Galactic latitude (b = -3.47 deg), we cannot rule out a Galactic origin.
The XRT began observing at 19:09:14.0 UT, 3610 seconds after the BAT trigger. In 5.7 ks of Photon Counting (PC) data one faint X-ray source is detected inside the BAT error circle. The astrometrically corrected X-ray position of the source (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue) is: RA, Dec = 213.63218, -64.93914 which is equivalent to:
```
RA (J2000): 14h 14m 31.72s
Dec (J2000): -64d 56' 20.9"
```
with an uncertainty of 7.0 arcsec (radius, 90% confidence). Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
The X-ray source is faint, at an average count rate of ~0.005 cnts/sec, below the RASS 3-sigma limit at this position in the sky. If the source is indeed the X-ray afterglow of GRB 151004A, it would be one of the faintest ever observed by the XRT at that time after the GRB trigger. At this time, there is only marginal evidence (1.5 sigma) of fading in the X-ray lightcurve and additional observations are required to establish the nature of the source.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/657564/BA/
GCN Circular #18423
C. Pagani, K. L. Page, P. A. Evans (U. Leicester) and S. B. Cenko (GSFC) report on behalf of the Swift-XRT team:
A second epoch of XRT data was collected on the field of the Swift Trigger 657564 / GRB 151004A (Cenko et al., GCN Circ. 18389) on 2015 October 15. The observations consist of 7.7 ks of PC mode data, from T0+885 ks to T0+932 ks.
The candidate X-ray source reported in Barthelmy et al., GCN Circ. 18396, originally detected at a count rate of 4.8 (+/- 1.14) x 10^-3 cnts/sec (0.3-10 keV) is not detected in this second epoch of observations, with a 3 sigma upper limit of 1.5 x 10^-3 cnts/sec (0.3-10 keV). The fading confirms that this is the X-ray afterglow of the Swift Trigger 657564 / GRB 151004A.
This circular is an official product of the Swift-XRT team.

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Jochen Greiner, last update: 16-Oct-2015 [Disclaimer]