Gamma-ray Burst 141015A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 15 Oct 14 09:13:42 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     615399,   Seg_Num: 0
GRB_RA:           87.507d {+05h 50m 02s} (J2000),
                  87.724d {+05h 50m 54s} (current),
                  86.774d {+05h 47m 06s} (1950)
GRB_DEC:         +18.316d {+18d 18' 57"} (J2000),
                 +18.319d {+18d 19' 09"} (current),
                 +18.302d {+18d 18' 07"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       7779 [cnts]    Image_Peak=264 [image_cnts]
TRIGGER_DUR:     2.048 [sec] 
TRIGGER_INDEX:   443     E_range: 15-50 keV
BKG_INTEN:       80453 [cnts]
BKG_TIME:        33147.34 SOD {09:12:27.34} UT
BKG_DUR:         24 [sec]
GRB_DATE:        16945 TJD;   288 DOY;   14/10/15
GRB_TIME:        33179.34 SOD {09:12:59.34} UT
GRB_PHI:         -85.17 [deg]
GRB_THETA:         9.96 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     9.79 [sigma]
IMAGE_SIGNIF:    7.99 [sigma]
MERIT_PARAMS:     +1  +0  +0  +1  +1  -2  -5  +1 +40  +0 
SUN_POSTN:       200.28d {+13h 21m 08s}   -8.55d {-08d 32' 44"}
SUN_DIST:        114.01 [deg]   Sun_angle= 7.5 [hr] (West of Sun)
MOON_POSTN:      108.16d {+07h 12m 38s}  +17.05d {+17d 02' 46"}
MOON_DIST:        19.50 [deg]
MOON_ILLUM:      54 [%]
GAL_COORDS:      189.63, -4.61 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       87.62, -5.10 [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 = 321.36,7.62 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 15 Oct 14 09:17:42 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     615399,   Seg_Num: 0
GRB_RA:           87.507d {+05h 50m 02s} (J2000),
                  87.724d {+05h 50m 54s} (current),
                  86.774d {+05h 47m 06s} (1950)
GRB_DEC:         +18.316d {+18d 18' 57"} (J2000),
                 +18.319d {+18d 19' 09"} (current),
                 +18.302d {+18d 18' 07"} (1950)
GRB_DATE:        16945 TJD;   288 DOY;   14/10/15
GRB_TIME:        33179.34 SOD {09:12:59.34} UT
TRIGGER_INDEX:   443
GRB_PHI:         -85.17 [deg]
GRB_THETA:         9.96 [deg]
DELTA_TIME:      0.00 [sec]
TRIGGER_DUR:     2.048 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     9.79 [sigma]
IMAGE_SIGNIF:    7.99 [sigma]
LC_URL:          sw00615399000msb.lc
SUN_POSTN:       200.29d {+13h 21m 09s}   -8.55d {-08d 32' 47"}
SUN_DIST:        114.01 [deg]   Sun_angle= 7.5 [hr] (West of Sun)
MOON_POSTN:      108.19d {+07h 12m 46s}  +17.04d {+17d 02' 30"}
MOON_DIST:        19.53 [deg]
MOON_ILLUM:      54 [%]
GAL_COORDS:      189.63, -4.61 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       87.62, -5.10 [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 = 321.36,7.62 [deg].

GCN Circular #16909
E. Troja (NASA/GSFC/UMCP), S. D. Barthelmy (GSFC), M. M. Chester (PSU), P. A. Evans (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), J. L. Racusin (NASA/GSFC) and R. L. C. Starling (U Leicester) report on behalf of the Swift Team:
At 09:12:59 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 141015A (trigger=615399). Swift did not slew because of Moon constraint. The BAT on-board calculated location is RA, Dec 87.507, +18.316 which is
```
   RA(J2000)  =  05h 50m 02s
   Dec(J2000) = +18d 18' 57"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single peak with a duration of about 10 sec. The peak count rate was ~800 counts/sec (15-350 keV), at ~0 sec after the trigger.
Due to a Moon observing constraint, Swift cannot slew to the BAT position until 15:56 UT on 2014 October 15. There will thus be no XRT or UVOT data for this trigger before this time.
Burst Advocate for this burst is E. Troja (eleonora.troja 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:     Wed 15 Oct 14 15:08:07 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     615399,   Seg_Num: 0
POINT_RA:         87.495d {+05h 49m 59s} (J2000)
POINT_DEC:       +18.323d {+18d 19' 21"} (J2000)
IMG_START_DATE:  16945 TJD;   288 DOY;   14/10/15
IMG_START_TIME:  54476.65 SOD {15:07:56.65} UT,   21234.7 [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:     Wed 15 Oct 14 15:11:05 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     615399,   Seg_Num: 0
POINT_RA:         87.495d {+05h 49m 59s} (J2000)
POINT_DEC:       +18.323d {+18d 19' 21"} (J2000)
POINT_ROLL:      91.317d
IMG_START_DATE:  16945 TJD;   288 DOY;   14/10/15
IMG_START_TIME:  54480.62 SOD {15:08:00.62} UT,   21238.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.393
N_STARS:         190
X_OFFSET:        582 [pixels]
Y_OFFSET:        535 [pixels]
X_MAX:           1541 [pixels]
Y_MAX:           1494 [pixels]
DET_THRESH:      15
PHOTO_THRESH:    8
SL_URL:          sw00615399000msufc435078480.fits
SUN_POSTN:       200.51d {+13h 22m 03s}   -8.64d {-08d 38' 14"}
SUN_DIST:        114.26 [deg]   Sun_angle= 7.5 [hr] (West of Sun)
MOON_POSTN:      111.26d {+07h 25m 02s}  +16.64d {+16d 38' 18"}
MOON_DIST:        22.51 [deg]
MOON_ILLUM:      52 [%]
GAL_COORDS:      189.62, -4.62 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       87.61, -5.10 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 15 Oct 14 15:11:30 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     615399,   Seg_Num: 0
POINT_RA:         87.495d {+05h 49m 59s} (J2000)
POINT_DEC:       +18.323d {+18d 19' 21"} (J2000)
POINT_ROLL:      91.317d
IMG_START_DATE:  16945 TJD;   288 DOY;   14/10/15
IMG_START_TIME:  54480.62 SOD {15:08:00.62} UT,   21238.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.393
N_STARS:         190
X_OFFSET:        582 [pixels]
Y_OFFSET:        535 [pixels]
X_MAX:           1541 [pixels]
Y_MAX:           1494 [pixels]
DET_THRESH:      15
PHOTO_THRESH:    8
SL_URL:          sw00615399000msufc435078480.fits
SUN_POSTN:       200.51d {+13h 22m 03s}   -8.64d {-08d 38' 14"}
SUN_DIST:        114.26 [deg]   Sun_angle= 7.5 [hr] (West of Sun)
MOON_POSTN:      111.26d {+07h 25m 03s}  +16.64d {+16d 38' 16"}
MOON_DIST:        22.51 [deg]
MOON_ILLUM:      52 [%]
GAL_COORDS:      189.62, -4.62 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       87.61, -5.10 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 15 Oct 14 15:13:18 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     615399,   Seg_Num: 0
POINT_RA:         87.495d {+05h 49m 59s} (J2000)
POINT_DEC:       +18.323d {+18d 19' 21"} (J2000)
ROLL:            91.317d
IMG_START_DATE:  16945 TJD;   288 DOY;   14/10/15
IMG_START_TIME:  54480.62 SOD {15:08:00.62} UT,   21238.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     435078493
X_OFFSET:        901 [pixels]
Y_OFFSET:        854 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1061
Y_GRB_POS:       1014
BINNING_INDEX:   1
IM_URL:          sw00615399000msuni435078493.fits
SUN_POSTN:       200.52d {+13h 22m 04s}   -8.64d {-08d 38' 16"}
SUN_DIST:        114.27 [deg]   Sun_angle= 7.5 [hr] (West of Sun)
MOON_POSTN:      111.28d {+07h 25m 07s}  +16.64d {+16d 38' 09"}
MOON_DIST:        22.53 [deg]
MOON_ILLUM:      52 [%]
GAL_COORDS:      189.62, -4.62 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       87.61, -5.10 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 15 Oct 14 15:13:28 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     615399,   Seg_Num: 0
POINT_RA:         87.495d {+05h 49m 59s} (J2000)
POINT_DEC:       +18.323d {+18d 19' 21"} (J2000)
ROLL:            91.317d
IMG_START_DATE:  16945 TJD;   288 DOY;   14/10/15
IMG_START_TIME:  54480.62 SOD {15:08:00.62} UT,   21238.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     435078493
X_OFFSET:        901 [pixels]
Y_OFFSET:        854 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1061
Y_GRB_POS:       1014
BINNING_INDEX:   1
IM_URL:          sw00615399000msuni435078493.fits
SUN_POSTN:       200.52d {+13h 22m 04s}   -8.64d {-08d 38' 16"}
SUN_DIST:        114.27 [deg]   Sun_angle= 7.5 [hr] (West of Sun)
MOON_POSTN:      111.28d {+07h 25m 07s}  +16.64d {+16d 38' 08"}
MOON_DIST:        22.53 [deg]
MOON_ILLUM:      52 [%]
GAL_COORDS:      189.62, -4.62 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       87.61, -5.10 [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 #16910
E. Troja (NASA/GSFC/UMCP), S. D. Barthelmy (GSFC), M. M. Chester (PSU), P. A. Evans (U Leicester), J. A. Kennea (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL), J. L. Racusin (NASA/GSFC), M. H. Siegel (PSU) and R. L. C. Starling (U Leicester) report on behalf of the Swift Team:
At 09:12:59 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 141015A (trigger=615399). The position was reloaded up to Swift using the "grb" mode of the TOO command (now that the location is out of Moon constraint). As such, Swift responds by generating the standard set of real-time TDRSS messages (and hence the GCN Notices). We are issuing this Circular with the results from XRT and UVOT.
The XRT began observing the field at 15:07:56.6 UT, 21297.3 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 87.51746, 18.32965 which is equivalent to:
```
   RA(J2000)  = 05h 50m 04.19s
   Dec(J2000) = +18d 19' 46.7"
```
with an uncertainty of 4.0 arcseconds (radius, 90% containment). This location is 60 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. 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 5.59 x 10^21 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 21238 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected.
Burst Advocate for this burst is E. Troja (eleonora.troja 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 Circular #16911
L. Elenin (KIAM), E. Mazaeva (IKI), A. Volnova (IKI), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of the Swift GRB 141015A (Troja et al., GCN 16909) with 0.4-m telescope of ISON-NM observatory starting on Oct., 15 (UT) 09:16:55, i.e. ~4 minutes after burst triger. We obtained 14 unfiltered images of 120 s exposure. We do not detect any source within XRT error circle (Troja et al., GCN 16910):
```
UT start   t-T0         Exp.      Filter  UL (3sigma)
          (mid.,days)    (s)
09:16:55  0.0068        5*120    Clear   18.4
09:16:55  0.0131       14*120    Clear   19.0
```
The photometry is based on nearby USNO-B1.0 stars
```
USNO-B1.0      RA             DEC            R2
1083-0107546   087,552978    +18,360067     14,78
1083-0107529   087,547650    +18,355839     15,18
1083-0107484   087,534895    +18,341425     15,00
1083-0107360   087,503081    +18,336089     14,71
```
GCN Circular #16912
Adria C. Updike (Roger Williams University) and Dieter H. Hartmann (Clemson University) report on behalf of the AZTEC collaboration:
We observed the field of the Swift GRB 141015A (Troja et al., GCN 16909) with the 0.6-m Super-LOTIS telescope at Kitt Peak National Observatory in Arizona under good conditions. Super-LOTIS began taking images 81 seconds after the trigger and continued for 37 minutes, obtaining 10 sec, 20 sec, and 60 sec images in the R band. We do not detect any source within the XRT error circle (Troja et al., GCN 16910):
```
UT midtime     Exp Time        Filter      Upper Limit
-------------------------------------------------------------------
09:15:01          4 x 10 sec         R           16.5
09:16:50          5 x 20 sec         R           17.4
09:23:35         10 x 60 sec         R           19.0
```
with photometry based on the USNO B1.0 catalog.
GCN Circular #16913
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team.
Using 1819 s of XRT Photon Counting mode data and 4 UVOT images for GRB 141015A, 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 = 87.51892, +18.32940 which is equivalent to:
```
RA (J2000): 05h 50m 4.54s
Dec (J2000): +18d 19' 45.8"
```
with an uncertainty of 2.3 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 #16914
Owen Littlejohns (ASU), Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Eleonora Troja (GSFC), Enrico Ramirez-Ruiz (UCSC), Jos=C3=A9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=C3=BAs Gonz=C3=A1lez (UNAM), Carlos Rom=C3=A1n-Z=C3=BA= =C3=B1iga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
We observed the field of GRB 141015A (Troja, et al., GCN 16909) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astron=C3=B3mico Nacional on Sierra San Pedro M=C3=A1rtir from 2014/10 15.39 to 2014/10 15.53 UTC (0.05 to 3.59 hours after the BAT trigger), obtaining a total of 2.44 hours exposure in the r and i bands.
For a source within the Swift/XRT error circle (Troja, et al., GCN 16910), we obtain the following upper limits (3-sigma):
```
  r     > 23.07
  i     > 22.48
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB.
We thank the staff of the Observatorio Astron=C3=B3mico Nacional in San Pedro M=C3=A1rtir.
GCN Circular #16915
J. Japelj (U. Ljubljana) and C. Guidorzi (U. Ferrara) on behalf of a large collaboration report:
We observed the position of GRB 141015A (Troja et al. GCN Circ. 16909) with the 1-m McDonald telescope (Fort Davis, US), a member of the Las Cumbres Observatory network. Observations started on October 15 at 09:51:01 UT, i.e., 38 minutes after the GRB trigger time (GCN Circ. 16909) and were done with the g', r' and i' filters.
We did not find a new source within the enhanced XRT error circle (Evans et al. GCN Circ. 16913) down to the following limits:
```
Mid time from  Total Exp   Filter    Magnitude
trigger (min)          (s)
-----------------------------------------------------------
54.4                       600        r'        > 19.6
59.2                       600        i'        > 18.7
-----------------------------------------------------------
```
Magnitudes are calibrated against nearby USNO-B1 stars.
GCN Circular #16916
A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), E. Troja (NASA/GSFC/UMCP), J. Tueller (GSFC), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 141015A (trigger #615399) (Troja, et al., GCN Circ. 16909). The BAT ground-calculated position is RA, Dec = 87.535, 18.370 deg, which is
```
   RA(J2000)  =  05h 50m 08.5s 
   Dec(J2000) = +18d 22' 12.5" 
```
with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 98%.
The mask-weighted light curve shows s single FRED-like pulse starting at ~T_0, peaking at ~T+1 sec, and ending at ~T+12 sec. T90 (15-350 keV) is 11.0 +- 4.1 sec (estimated error including systematics).
The time-averaged spectrum from T+0.00 to T+13.00 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.90 +- 0.37. The fluence in the 15-150 keV band is 1.6 +- 0.4 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+1.00 sec in the 15-150 keV band is 0.5 +- 0.1 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/615399/BA/
GCN Circular #16917
D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ), S. Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of MITSuME and OISTER collaboration:
We observed the field of GRB 141015A (Troja et al., GCNC 16909) with the optical three color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory.
The observation started on 2014-10-15 13:44:05 UT, (~4.5 h after the burst). We did not find any new point source within the enhanced XRT circle (Evans, GCNC 16913) 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
-----------------------------------------------------
0.29816    16:22:18    5760.0   >20.1  >19.8  >19.0
-----------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
```
GCN Circular #16918
A. A. Breeveld (UCL-MSSL) and E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 141015A 21301 s after the BAT trigger (Troja et al., GCN Circ. 16909). No optical afterglow consistent with the XRT position (Evans et al. GCN Circ. 16913) 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         21301        21451          147         >20.5
white            21301        23280         1033         >21.5
v                27071        27978          885         >19.8
b                21461        22368          885         >20.8
w1               28890        29661          759         >20.1
m2               27983        28883          886         >20.3
w2               23286        23906          610         >20.1
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.51 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #16923
Y. Yano, T. Yoshii, Y. Saito, Y. Tachibana, H. Ohuchi, S. Kurita, Y. Ono, T. Fujiwara, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration:
We observed the field of GRB 141015A (E. Troja et al., GCN Circular #16909) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan.
The observation started on 2014-10-15 14:40:07 UT (~5.5 h after the burst). We did not find any new point source within the enhanced XRT circle (P. A. Evans et al., GCN Circular #16913) in all the three bands.
The measured magnitudes are listed below.
```
T0+[sec]     MID-UT    T-EXP[sec]        g'         Rc        Ic
------------------------------------------------------------------------------
31113        18:00:29      1440           >20.7  >20.1  >19.3
------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
```
GCN Circular #16925
E. Troja (NASA/GSFC/UMCP) reports on behalf of the Swift-XRT team:
We have analysed 9.0 ks of XRT data for GRB 141015A (Troja et al. GCN Circ. 16909), from 21.3 ks to 271.2 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN Circ. 16913).
The GRB light curve in the initial observation was at a level of ~0.02 ct/sec in XRT. In subsequent observations the GRB is undetected, with an upper limit of 0.004 ct/sec, we therefore confirm that this was the afterglow of GRB 141015A.
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.38 (+0.51, -0.20). The best-fitting absorption column is consistent with the Galactic value of 5.6 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 6.0 x 10^-11 (7.5 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     5.6 (+/-3.8) x 10^21 cm^-2
Galactic foreground: 5.6 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.38 (+0.51, -0.20)
```
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00615399.
This circular is an official product of the Swift-XRT team.
GCN Circular #16940
D. Kawamura, T. Sakamoto, A. Yoshida (AGU)
We observed the field of GRB 141015A detected by Swift (trigger #615399; Troja et al., GCN Circ. 16909) with the iTelescope.Net (http://www.itelescope.net) T05 (0.25 m Takahashi Epsilon) telescope located at the New Mexico Skies Observatory (NM, USA).
20 images of 60 sec exposures were taken in the Red filter starting from October 15 09:37:23 (UT) about 26 minutes after the trigger and stopped on October 5 10:04:00 (UT). We do not detect the optical afterglow both in the individual images and the stacked image at the enhanced X-ray afterglow position (Evans et al., GCN Circ. 16913). The estimated five sigma upper limit of the combined image (total exposure of 1200 sec) is ~17.1 using the USNO-B1 catalog.
GCN Circular #17066
Klotz A., Turpin D. (IRAP-CNRS-OMP), Boer M., Gendre B., Siellez K., Dereli H., Bardho O. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report:
We imaged the field of GRB 141015A detected by SWIFT (trigger 615399) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile.
The observations started 55s after the GRB trigger (19s after the notice). The elevation of the field decreased from 42 degrees above horizon but it was dawn (sun elevation -11 deg).
The first image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39). We do not detect any OT with a limiting magnitude of: t0+55s to t0+115s : R > 12.2
Later images were acquired in tracking mode until 521 seconds after the trigger. We detect no optical afterglow at Rlim = 12.5
Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction.

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Jochen Greiner, last update: 13-Nov-2014 [Disclaimer]