- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Sun 01 Mar 15 06:21:39 UT
NOTICE_TYPE: Swift-BAT GRB Position
TRIGGER_NUM: 633105, Seg_Num: 0
GRB_RA: 11.332d {+00h 45m 20s} (J2000),
11.541d {+00h 46m 10s} (current),
10.644d {+00h 42m 35s} (1950)
GRB_DEC: +41.857d {+41d 51' 26"} (J2000),
+41.940d {+41d 56' 23"} (current),
+41.584d {+41d 35' 02"} (1950)
GRB_ERROR: 3.00 [arcmin radius, statistical only]
GRB_INTEN: 15263 [cnts] Image_Peak=404 [image_cnts]
TRIGGER_DUR: 4.096 [sec]
TRIGGER_INDEX: 289 E_range: 15-50 keV
BKG_INTEN: 133288 [cnts]
BKG_TIME: 22794.75 SOD {06:19:54.75} UT
BKG_DUR: 40 [sec]
GRB_DATE: 17082 TJD; 60 DOY; 15/03/01
GRB_TIME: 22854.14 SOD {06:20:54.14} UT
GRB_PHI: -103.90 [deg]
GRB_THETA: 21.89 [deg]
SOLN_STATUS: 0x10103
RATE_SIGNIF: 13.60 [sigma]
IMAGE_SIGNIF: 8.75 [sigma]
MERIT_PARAMS: +1 +0 +0 +2 +1 -1 +0 +0 -55 +0
SUN_POSTN: 341.85d {+22h 47m 24s} -7.69d {-07d 41' 21"}
SUN_DIST: 56.57 [deg] Sun_angle= -2.0 [hr] (East of Sun)
MOON_POSTN: 112.11d {+07h 28m 27s} +16.69d {+16d 41' 15"}
MOON_DIST: 86.49 [deg]
MOON_ILLUM: 83 [%]
GAL_COORDS: 121.71,-21.00 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 28.69, 33.64 [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 position matches one of the nearby galaxy sources in the on-board catalog!
COMMENTS: This does not match any source in the on-board catalog.
COMMENTS: This matches a source in the ground catalog: M31_0,2, delta=0.262 [deg].
COMMENTS: The position is inside the galaxy NGC224 (of total mag=3.50 and dia=178.00 arcmin).
COMMENTS: There is a 0.03% probability that this would happen by chance coincidence.
COMMENTS: This is a GRB in nearby galaxy or it is noise.
COMMENTS: This trigger occurred at longitude,latitude = 148.18,3.16 [deg].
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Sun 01 Mar 15 06:22:38 UT
NOTICE_TYPE: Swift-XRT Nack-Position
TRIGGER_NUM: 633105, Seg_Num: 0
POINT_RA: 11.350d {+00h 45m 24s} (J2000)
POINT_DEC: +41.879d {+41d 52' 46"} (J2000)
IMG_START_DATE: 17082 TJD; 60 DOY; 15/03/01
IMG_START_TIME: 22952.47 SOD {06:22:32.47} UT, 98.3 [sec] since BAT Trigger Time
COUNTS: 3 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.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Sun 01 Mar 15 06:27:38 UT
NOTICE_TYPE: Swift-UVOT Source List
TRIGGER_NUM: 633105, Seg_Num: 0
POINT_RA: 11.350d {+00h 45m 24s} (J2000)
POINT_DEC: +41.880d {+41d 52' 46"} (J2000)
POINT_ROLL: 215.842d
IMG_START_DATE: 17082 TJD; 60 DOY; 15/03/01
IMG_START_TIME: 22956.58 SOD {06:22:36.58} UT, 102.4 [sec] since BAT Trigger Time
FILTER: 10, White
BKG_MEAN: 7.181
N_STARS: 86
X_OFFSET: 649 [pixels]
Y_OFFSET: 429 [pixels]
X_MAX: 1608 [pixels]
Y_MAX: 1388 [pixels]
DET_THRESH: 23
PHOTO_THRESH: 14
SL_URL: sw00633105000msufc0102.fits
SUN_POSTN: 341.86d {+22h 47m 25s} -7.69d {-07d 41' 15"}
SUN_DIST: 56.59 [deg] Sun_angle= -2.0 [hr] (East of Sun)
MOON_POSTN: 112.16d {+07h 28m 39s} +16.68d {+16d 40' 52"}
MOON_DIST: 86.51 [deg]
MOON_ILLUM: 83 [%]
GAL_COORDS: 121.73,-20.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 28.72, 33.66 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Source List.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Sun 01 Mar 15 06:28:01 UT
NOTICE_TYPE: Swift-UVOT Processed Source List
TRIGGER_NUM: 633105, Seg_Num: 0
POINT_RA: 11.350d {+00h 45m 24s} (J2000)
POINT_DEC: +41.880d {+41d 52' 46"} (J2000)
POINT_ROLL: 215.842d
IMG_START_DATE: 17082 TJD; 60 DOY; 15/03/01
IMG_START_TIME: 22956.58 SOD {06:22:36.58} UT, 102.4 [sec] since BAT Trigger Time
FILTER: 10, White
BKG_MEAN: 7.181
N_STARS: 86
X_OFFSET: 649 [pixels]
Y_OFFSET: 429 [pixels]
X_MAX: 1608 [pixels]
Y_MAX: 1388 [pixels]
DET_THRESH: 23
PHOTO_THRESH: 14
SL_URL: sw00633105000msufc0102.fits
SUN_POSTN: 341.86d {+22h 47m 25s} -7.69d {-07d 41' 15"}
SUN_DIST: 56.59 [deg] Sun_angle= -2.0 [hr] (East of Sun)
MOON_POSTN: 112.17d {+07h 28m 40s} +16.68d {+16d 40' 50"}
MOON_DIST: 86.51 [deg]
MOON_ILLUM: 83 [%]
GAL_COORDS: 121.73,-20.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 28.72, 33.66 [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 01 Mar 15 06:29:12 UT
NOTICE_TYPE: Swift-UVOT Image
TRIGGER_NUM: 633105, Seg_Num: 0
POINT_RA: 11.350d {+00h 45m 24s} (J2000)
POINT_DEC: +41.880d {+41d 52' 46"} (J2000)
ROLL: 215.842d
IMG_START_DATE: 17082 TJD; 60 DOY; 15/03/01
IMG_START_TIME: 22956.58 SOD {06:22:36.58} UT, 102.4 [sec] since BAT Trigger Time
FILTER: 10, White
EXPOSURE_ID: 446883769
X_OFFSET: 968 [pixels]
Y_OFFSET: 748 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 1128
Y_GRB_POS: 908
BINNING_INDEX: 1
IM_URL: sw00633105000msuni0116.fits
SUN_POSTN: 341.86d {+22h 47m 26s} -7.69d {-07d 41' 14"}
SUN_DIST: 56.59 [deg] Sun_angle= -2.0 [hr] (East of Sun)
MOON_POSTN: 112.18d {+07h 28m 42s} +16.68d {+16d 40' 45"}
MOON_DIST: 86.52 [deg]
MOON_ILLUM: 83 [%]
GAL_COORDS: 121.73,-20.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 28.72, 33.66 [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 01 Mar 15 06:29:29 UT
NOTICE_TYPE: Swift-UVOT Processed Image
TRIGGER_NUM: 633105, Seg_Num: 0
POINT_RA: 11.350d {+00h 45m 24s} (J2000)
POINT_DEC: +41.880d {+41d 52' 46"} (J2000)
ROLL: 215.842d
IMG_START_DATE: 17082 TJD; 60 DOY; 15/03/01
IMG_START_TIME: 22956.58 SOD {06:22:36.58} UT, 102.4 [sec] since BAT Trigger Time
FILTER: 10, White
EXPOSURE_ID: 446883769
X_OFFSET: 968 [pixels]
Y_OFFSET: 748 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 1128
Y_GRB_POS: 908
BINNING_INDEX: 1
IM_URL: sw00633105000msuni0116.fits
SUN_POSTN: 341.86d {+22h 47m 26s} -7.69d {-07d 41' 13"}
SUN_DIST: 56.59 [deg] Sun_angle= -2.0 [hr] (East of Sun)
MOON_POSTN: 112.18d {+07h 28m 43s} +16.68d {+16d 40' 44"}
MOON_DIST: 86.52 [deg]
MOON_ILLUM: 83 [%]
GAL_COORDS: 121.73,-20.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 28.72, 33.66 [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: Sun 01 Mar 15 06:35:27 UT
NOTICE_TYPE: Swift-UVOT Processed Source List
TRIGGER_NUM: 633105, Seg_Num: 0
POINT_RA: 11.351d {+00h 45m 24s} (J2000)
POINT_DEC: +41.883d {+41d 52' 60"} (J2000)
POINT_ROLL: 215.843d
IMG_START_DATE: 17082 TJD; 60 DOY; 15/03/01
IMG_START_TIME: 23115.94 SOD {06:25:15.94} UT, 261.8 [sec] since BAT Trigger Time
FILTER: 7, U
BKG_MEAN: 2.098
N_STARS: 177
X_OFFSET: 409 [pixels]
Y_OFFSET: 189 [pixels]
X_MAX: 1848 [pixels]
Y_MAX: 1628 [pixels]
DET_THRESH: 12
PHOTO_THRESH: 6
SL_URL: sw00633105000msufc0261.fits
SUN_POSTN: 341.86d {+22h 47m 27s} -7.69d {-07d 41' 08"}
SUN_DIST: 56.59 [deg] Sun_angle= -2.0 [hr] (East of Sun)
MOON_POSTN: 112.23d {+07h 28m 55s} +16.67d {+16d 40' 20"}
MOON_DIST: 86.56 [deg]
MOON_ILLUM: 83 [%]
GAL_COORDS: 121.73,-20.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 28.72, 33.66 [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 01 Mar 15 06:36:29 UT
NOTICE_TYPE: Swift-UVOT Image
TRIGGER_NUM: 633105, Seg_Num: 0
POINT_RA: 11.351d {+00h 45m 24s} (J2000)
POINT_DEC: +41.883d {+41d 52' 60"} (J2000)
ROLL: 215.843d
IMG_START_DATE: 17082 TJD; 60 DOY; 15/03/01
IMG_START_TIME: 23115.94 SOD {06:25:15.94} UT, 261.8 [sec] since BAT Trigger Time
FILTER: 7, U
EXPOSURE_ID: 446883929
X_OFFSET: 968 [pixels]
Y_OFFSET: 748 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 1128
Y_GRB_POS: 908
BINNING_INDEX: 1
IM_URL: sw00633105000msuni0275.fits
SUN_POSTN: 341.86d {+22h 47m 27s} -7.69d {-07d 41' 07"}
SUN_DIST: 56.59 [deg] Sun_angle= -2.0 [hr] (East of Sun)
MOON_POSTN: 112.24d {+07h 28m 58s} +16.67d {+16d 40' 16"}
MOON_DIST: 86.57 [deg]
MOON_ILLUM: 83 [%]
GAL_COORDS: 121.73,-20.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 28.72, 33.66 [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 01 Mar 15 06:35:00 UT
NOTICE_TYPE: Swift-UVOT Source List
TRIGGER_NUM: 633105, Seg_Num: 0
POINT_RA: 11.351d {+00h 45m 24s} (J2000)
POINT_DEC: +41.883d {+41d 52' 60"} (J2000)
POINT_ROLL: 215.843d
IMG_START_DATE: 17082 TJD; 60 DOY; 15/03/01
IMG_START_TIME: 23115.94 SOD {06:25:15.94} UT, 261.8 [sec] since BAT Trigger Time
FILTER: 7, U
BKG_MEAN: 2.098
N_STARS: 177
X_OFFSET: 409 [pixels]
Y_OFFSET: 189 [pixels]
X_MAX: 1848 [pixels]
Y_MAX: 1628 [pixels]
DET_THRESH: 12
PHOTO_THRESH: 6
SL_URL: sw00633105000msufc0261.fits
SUN_POSTN: 341.86d {+22h 47m 26s} -7.69d {-07d 41' 08"}
SUN_DIST: 56.59 [deg] Sun_angle= -2.0 [hr] (East of Sun)
MOON_POSTN: 112.23d {+07h 28m 54s} +16.67d {+16d 40' 22"}
MOON_DIST: 86.56 [deg]
MOON_ILLUM: 83 [%]
GAL_COORDS: 121.73,-20.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 28.72, 33.66 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Source List.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Sun 01 Mar 15 06:36:45 UT
NOTICE_TYPE: Swift-UVOT Processed Image
TRIGGER_NUM: 633105, Seg_Num: 0
POINT_RA: 11.351d {+00h 45m 24s} (J2000)
POINT_DEC: +41.883d {+41d 52' 60"} (J2000)
ROLL: 215.843d
IMG_START_DATE: 17082 TJD; 60 DOY; 15/03/01
IMG_START_TIME: 23115.94 SOD {06:25:15.94} UT, 261.8 [sec] since BAT Trigger Time
FILTER: 7, U
EXPOSURE_ID: 446883929
X_OFFSET: 968 [pixels]
Y_OFFSET: 748 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 1128
Y_GRB_POS: 908
BINNING_INDEX: 1
IM_URL: sw00633105000msuni0275.fits
SUN_POSTN: 341.86d {+22h 47m 27s} -7.69d {-07d 41' 06"}
SUN_DIST: 56.59 [deg] Sun_angle= -2.0 [hr] (East of Sun)
MOON_POSTN: 112.24d {+07h 28m 58s} +16.67d {+16d 40' 15"}
MOON_DIST: 86.57 [deg]
MOON_ILLUM: 83 [%]
GAL_COORDS: 121.73,-20.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 28.72, 33.66 [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 #17512
TITLE: GCN CIRCULAR
NUMBER: 17512
SUBJECT: Trigger 633105 is likely not a GRB
DATE: 15/03/01 07:00:38 GMT
FROM: Amy Lien at GSFC
A. Y. Lien (GSFC/UMBC), A. Maselli (INAF-IASFPA) and
M. H. Siegel (PSU) report on behalf of the Swift Team:
At 06:20:54 UT, the Swift Burst Alert Telescope (BAT) triggered and
located a source close to M31 (NGC224) (trigger=633105). Swift slewed
immediately to the source.
The BAT on-board calculated location is
RA, Dec 11.332, +41.857 which is
RA(J2000) = 00h 45m 20s
Dec(J2000) = +41d 51' 26"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a multi-peaked
structure with a duration of about 20 sec. The peak count rate
was ~1000 counts/sec (15-350 keV), at ~3 sec after the trigger.
The XRT began observing the field at 06:22:32.4 UT, 98.3 seconds after
the BAT trigger. No source was detected in 604 s of promptly downlinked
data, which covered 91% of the BAT error circle. We are waiting for the
full dataset to detect and localise the XRT counterpart.
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 102 seconds after the BAT trigger. No new source has
been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of
the BAT error circle. Because of the density of catalogued stars, further
analysis is required to report an upper limit for any afterglow in the
sub-image. The 8'x8' region for the list of sources generated on-board covers
100% of the BAT error circle. Because of the density of catalogued stars,
further analysis is required to report an upper limit for any afterglow in the
region. No correction has been made for the expected extinction corresponding
to E(B-V) of 0.06.
Given the lack of a bright XRT source and the proximity of the BAT
trigger to M31, it is possible that this is a noise event and not an
astrophysical source. However, we note that the BAT image
significance is 8.75. The full ground-linked data set will be
necessary to verify.
Burst Advocate for this burst is A. Y. Lien (amy.y.lien 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 #17516
TITLE: GCN CIRCULAR
NUMBER: 17516
SUBJECT: GRB 150301C : (Swift trigger 633105) Swift observations
DATE: 15/03/01 20:31:02 GMT
FROM: Jay R. Cummings at NASA/GSFC/Swift
M. Stamatikos (OSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (CPI), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), J. Tueller (GSFC), T. N. Ukwatta (LANL),
F. Marshall (NASA/GSFC), D. Malesani (DARK/NBI), L. Hagen (PSU),
M. de Pasquale (INAF-IASFPA), A. Maselli (INAF-IASFPA), D.N. Burrows (PSU),
K. Page (UCL-MSSL), N. P. M. Kuin (UCL-MSSL)
Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of possible GRB 150301C (trigger #633105)
(Lien, et al., GCN Circ. 17512). The BAT ground-calculated position is
RA, Dec = 11.319, 41.861 deg which is
RA(J2000) = 00h 45m 16.6s
Dec(J2000) = +41d 51' 40.0"
with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment).
The significance in the BAT image was 10.1, so we are sure that this was
a real astrophysical source. The partial coding was 69%.
The location is well within the visible light of M31. A more distant galaxy,
[JSD2012] 170, which has a size of 0.11 arcmin, is within the BAT error
circle. In 1.9 ks of data, the Swift XRT found only a single very weak source
(2.8 sigma), consistent with the position of a known source within the BAT
error circle, [PFH2005] 622, with a count rate of (5.3+/-1.9) x 10^-03 c/s. We
cannot state whether there is any variability of this source at this time. The
XRT position of this source is:
RA (J2000) 00h 45m 14.4s
Dec (J2000) +41d 50' 37.7"
The BAT mask-weighted light curve shows a single weak FRED peak. T90 (15-350 keV)
is 14 +- 3 sec (estimated error including systematics).
The time-averaged BAT spectrum from T-0.6 to T+15.0 sec is best fit by a power-
law model with an exponential cutoff. The power law index of the time-averaged
spectrum is poorly defined but is nominally -0.8 +- 2. The peak energy is
38 +- 7 keV. The fluence in the 15-150 keV band is 2.1 +- 0.4 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T+1.32 sec in the 15-150 keV band is
0.6 +- 0.2 ph/cm2/sec. A simple power-law fit has a photon index of 1.96 +- 0.25.
All the quoted errors are at the 90% confidence level.
If this source was in M31, its isotropic energy output was 1.5 x 10^43 ergs
in 15.6 seconds in the range 15-150 keV.
It is very possible, given the softness of the source, that this is a non-GRB
in M31. The color:duration is within the distribution of long GRBs. No XRT
source was seen in the initial observations, whereas we might expect most
sources in M31 bright enough to be seen in BAT would be very bright in XRT.
Therefore the source is likely to be highly absorbed. The results of the
batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/633105/BA/
The Swift/UVOT began settled observations of the field 102 s after
the BAT trigger (Lien et al., GCN Circ. 17512). No new source within
the BAT error circle 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
exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 102 4151 369 >20.39
v 592 4562 216 >18.55
b 518 5241 96 >19.08
u 261 5177 461 >19.69
uvw1 641 4973 216 >19.27
uvm2 617 4768 216 >19.20
uvw2 568 4357 216 >19.41
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.06 in the direction of the burst
(Schlegel et al. 1998).
Further Swift observations are planned.
- GCN Circular #17536 == ATEL #7166
Phil Evans (U. Leicester) , Alessandro Maselli (INAF-IASFPA), David Burrows (PSU),
Sergio Campana (INAF-OAB), Neil Gehrels (GSFC), Jamie Kennea (PSU),
Amy Lien (GSFC/UMBC), Lea Hagen (PSU), Daniele Malesani (DARK/NBI),
Frank Marshall (GSFC), Julian Osborne (U. Leicester), Kim L. Page (U Leicester),
Massimiliano De Pasquale (INAF-IASFPA) report on behalf of the Swift team:
We report further XRT observations of the highly unusual transient or GRB detected
by BAT on March 1 ( trigger 633105 or GRB150301C; Lien et al., GCN Circ 17512;
Stamatikos et al., GCN Circ 17516). It lasted about 20 seconds in BAT and has a
location in M31, but had very weak X-ray emission. The XRT found a single source
within the BAT error circle, which is coincident with the known X-ray source [PFH2005] 622.
This source was previously reported in an XMM-Newton survey of M31 (Pietsch et al.,
A&A, 434, 483, 2005), and was classified as a "hard" source based on the hardness ratio (see
definition in Pietsch et al. 2005). The paper suggests that these "hard" sources may be
X-ray binaries, Crab-like SNRs, or AGNs.
Using the faint-source-optimised detection system from the 1SXPS catalogue (Evans et al.,
ApJS 210, 8, 2014), the XRT source is detected with a likelihood of 18.3 in the first observation
of the BAT error region. This corresponds to a "Good"-flagged object, i.e. a >3-sigma detection.
The refined XRT position is RA,Dec = 11.3107, +41.8431 degrees which corresponds to
RA (J2000): 00h 45m 14.57s
Dec (J2000): +41d 50' 35.1"
with an uncertainty of 5.7 arcsec (radius, 90% confidence). This is 4 arcsec from the catalogued
position of [PFH2005] 622, which is at RA=00h 45m 14.87,Dec=+41d 50' 33'' with an uncertainty
of 1.5 arcsec. Hence, the XRT position is consistent with the position of [PFH2005] 622.
During the first XRT observation, starting at T0+105s and lasting 1.9 ks, the source is detected with
a count-rate of 6.0 (+2.3, -1.8) x10^-3 ct/sec. In the subsequent observations, from T0+44.9 ks and
totalling 6ks exposure, the source is undetected, with an upper limit of 1.2 x10^-3 ct/sec, consistent
with fading.
Swift-XRT has previously observed this location for a total of ~4ks, corresponding to "Stacked image
7598" in the 1SXPS catalogue. The source was not detected in this dataset, with an upper limit of
2.2x10^-3 ct/sec, significantly below the level at which we have detected it in this observation.
Additionally, XMM-Newton observations (Pietsch et al., 2005) detected this X-ray source in 2005
with a flux of 6.9x10^-15 erg/cm^2/s. The peak rate in our observations corresponds to
~2x10^-13 erg/cm^2/s, i.e. ~35 times brighter than the XMM detection. At the distance of M31,
these fluxes correspond to a luminosity of ~5x10^35 erg/s (0.2-4.5 keV) in the XMM-Newton observations,
and ~1.4x10^37 erg/s (0.3-10 keV) in the XRT observations. For comparison, the average luminosity
in BAT at this distance was 1.25x10^42 erg/s in 15-150 keV (Stamatikos et al., GCN Circ 17516).
We therefore conclude that XRT has detected a bursting source that is likely the counterpart to
BAT trigger 633105.
- GCN Circular #17541
TITLE: GCN CIRCULAR
NUMBER: 17541
SUBJECT: Trigger 633105 (aka GRB150301C): Swift/UVOT Observations of XRT Counterpart
DATE: 15/03/04 03:16:06 GMT
FROM: Lea Hagen at PSU
L. M. Z. Hagen (PSU) and A. Y. Lien (GSFC/UMBC)
report on behalf of the Swift/UVOT team:
A point source is detected by UVOT that is consistent with the XRT
counterpart and 2.5 arcsec from the XMM-Newton source discussed in
Evans et al. (GCN Circ. 17536). This source is also seen in archival
DSS imaging. It is unclear if this is the same object detected by XRT
or a serendipitous source. Given how crowded the field is, it is also
likely that the UVOT source is comprised of multiple individual sources.
The coordinates of the UVOT source are
RA(J2000) = 00:45:14.76 = 11.31150
DEC(J2000) = +41:50:35.2 = 41.84311
Preliminary detections and 3-sigma upper limits using the UVOT
photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373)
for the available exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 102 4151 369 19.22+-0.13
v 592 4562 216 >18.53
b 518 5241 96 >19.08
u 261 5177 461 18.60+-0.15
uvw1 641 79666 5117 18.64+-0.05
uvm2 617 45953 1237 18.94+-0.13
uvw2 568 4357 216 18.99+-0.27
The magnitudes in the table are not corrected for the Galactic
extinction due to the reddening of E(B-V) = 0.06 in the direction
of the source (Schlegel et al. 1998).
This field has also been observed previously by UVOT as part of a
different observing campaign, primarily in 2013 and 2014. The
stacked images have the following detections:
Filter Exp(s) Mag
v 1406 19.04+-0.19
b 1445 19.77+-0.15
u 27521 18.65+-0.03
uvw1 52236 18.57+-0.02
uvm2 58908 18.65+-0.03
uvw2 65719 18.61+-0.02
These indicate possible variability of the source, but further
analysis will be required to confirm this.
- GCN Circular #17543
Z. Cano (Univ. Iceland), D. Malesani, J. P. U. Fynbo (DARK/NBI),
A. de Ugarte Postigo (IAA/CSIC and DARK/NBI), N. R. Tanvir (Univ.
Leicester),
P. Jakobsson (Univ. Iceland), M. Saajasto, T. Pursimo (NOT), report on
behalf of a larger collaboration:
We observed the field of BAT trigger 633105 (Lien et al., GCN Circ. 17512)
with the
2.5-m Nordic Optical Telescope (NOT) equipped with ALFOSC on 01-Mar-2015 and
03-Mar-2015, obtaining 6x300 s of SDSS r-band exposures in each epoch. The
mid
exposure times of our observations correspond to +0.60 and +2.59 days from
the
initial trigger, respectively.
Consistent with the X-ray position of the known source [PFH2005] 622
(thought to
be associated with the gamma-ray transient; Evans et al., GCN Circ. 17536),
we
detect one object at coordinates:
RA = 00:45:14.80
Dec = +41:50:32.35
Its magnitude is R = 22.7 +- 0.1 (using a USNO-A2.0 star in the field for
calibration). Two more objects are also detected in close proximity of the
XMM
position (Pietsch et al. 2005, A&A, 434, 483), and potentially consistent
with
it, including the source seen by UVOT by Hagen & Lien (GCN 17541), which
appears
to be quite blue (it has R = 22.3 +- 0.1 in our image).
We carried out digital image subtraction between our two images, where we
subtracted the first epoch from the second by using an adaptation of the
ISIS
software. In our difference image we do not detect any residual flux at the
combined XRT and XMM location, down to an upper limit of R > 23.2.
All objects seen in the NOT image are also apparent in the deep, archival
data
from the PAndAS survey (McConnachie et al. 2009, Nature, 461, 66), which
also reveals
a few more, fainter objects in the close proximity of the XMM position. No
object seems
to have varied significantly.
A gif animation of the two epochs of NOT imaging, and the difference image,
can
be retrieved from:
http://www.astro.ku.dk/~malesani/GRB/150301C/subtraction.gif
A comparison image of the NOT image from 01-Mar-2015 and the PAndAS image
can be found at:
http://www.astro.ku.dk/~malesani/GRB/150301C/comparison_NOT_PAndAS.png
- GCN Circular #17544
Alessandro Maselli (INAF-IASFPA), Phil Evans (U. Leicester),
David Burrows (PSU), Sergio Campana (INAF-OAB),
Neil Gehrels (GSFC), Jamie Kennea (PSU), Amy Lien (GSFC/UMBC),
Daniele Malesani (DARK/NBI), Craig. B. Markwardt (GSFC),
Frank Marshall (GSFC), Julian Osborne (U. Leicester),
David. M. Palmer (LANL), Kim L. Page (U Leicester),
Rhaana L. C. Starling (U Leicester)
report on behalf of the Swift team:
Swift continues to observe the field of BAT trigger 633105
(aka GRB 150301C) with sky location in M31. To avoid further
naming confusion, this object will be referred as Swift J0045.2+4151
hereafter. The XRT continues to detect only a single source within
the BAT error circle at a position coincident with the previously
known XMM-Newton source, [PFH2005] 622 (Pietsch et al. 2005).
For the rest of this circular we assume that the X-rays detected by
XRT are from [PFH2005] 622.
The XRT has acquired four observations so far. The source
(which we presume is [PFH2005] 622) was detected in the first snapshot,
(T0+107s to T0+720s), in which we detect 8 events in 614 seconds,
with a mean background expectation of 0.34 counts. This results in a rate
of 1.48 (+0.6, -0.5) e-2 counts/s (3 sigma errors).
In the 2nd epoch (T0+4 ks to T0+80 ks), we detect 3 events in 7.2 ks, with
an expected background of 1.25 events, giving a 3 sigma upper limit of
< 0.002 counts/s.
In the 3rd epoch (T0+171 ks to T0+206 ks), we find 5 events in 4.8 ks with a
mean background expectation of 0.64 events, giving a 3 sigma detection
of 1.2 (+0.8, -0.6) e-3 counts/s (3 sigma errors).
All measurements use a source radius of 9 pixels (21 arcseconds),
a background measurement from an annulus around the source region, and
the Bayesian method of Kraft, Burrows, and Nousek (1991, ApJ, 374, 344) to
+obtain
the 3 sigma confidence regions and upper limits.
Therefore, after a detection in the initial XRT observation, the source
faded below the XRT detection limit and may have brightened again
in the 3rd epoch.
We cannot conclude firmly at this point whether the source
[PFH2005] 622 is associated with the BAT trigger or not.
More observations at all wavelengths are encouraged.
A table and a light curve that summarize current XRT observations
of [PFH2005] 622 are available at:
http://swift.gsfc.nasa.gov/results/BATbursts/633105/xrt/atel_20150304.html
- GCN Circular #17545
T. Laskar, E. Berger (Harvard) and D. Fox (PSU) report on behalf of a larger
collaboration:
"We observed GRB 150301C (Lien et al; GCN 17512) with the VLA beginning on 2015
March 04.03 UT (2.77 days after the burst) at a mean frequency of 9.8 GHz.
No radio counterpart is detected in the 90-minute observation within the
XRT error circle (Evans et al; GCN 17536) to a 3 sigma upper limit of 18
uJy. The 90-minute observation covers the full BAT error circle and does not
contain any radio source brighter than the NVSS flux limit. Well-detected
sources fainter than the NVSS limit have been identified for possible
future monitoring. We thank the VLA staff for scheduling and obtaining
these observations."
- GCN Circular #17548
M. H. Siegel, L.M.Z. Hagen (PSU) and A. Y. Lien (GSFC/UMBC)
report on behalf of the Swift UVOT team:
Swift continues to observe the field of BAT trigger 633105 (formerly
GRB 150301C, now Swift J0045.2+4151) with a sky location in M31.
The UVOT data show no change in brightness in the optical source reported
in Hagen & Lien (GCN Circ 17541).
Preliminary detections and 3-sigma upper limits using the UVOT
photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373)
for the most recent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
v 338602 338728 124 >18.25
b 337955 338082 124 >19.12
u 337824 337951 124 18.45+-0.27
uvw1 337564 337819 250 18.82+-0.26
uvm2 326044 343973 4048 18.64+-0.06
uvw2 338088 338597 500 18.72+-0.14
All of these magnitudes are consistent, within uncertainties, of
our initial and archival measures.
We further report an analysis of 207 ks of archival UVOT data for
the source. Our analysis shows no previous variability in the source
in the UVOT photometry, which has a typical uncertainty of 0.2 mag in
the three UV filters.
- GCN Circular #17548 == ATEL # 7181
A. Belfiore (INAF/IASF Milano), A. Tiengo (IUSS Pavia), G. L. Israel
(INAF/OA Roma), A. M. Read (U. Leicester), R. Salvaterra, D. Salvetti
(INAF/IASF Milano), G. Novara (IUSS Pavia), S. Mereghetti, M. Marelli
(INAF/IASF Milano), G. Rodriguez (INAF/OA Roma), G. Lisini (IUSS Pavia),
S. R. Rosen (U. Leicester), A. De Luca (INAF/IASF Milano), report on ,
behalf of the EXTraS collaboration:
Based on the preliminary results of the EXTraS project (DeLuca et al.
2015, arXiv:1503.01497), we report on the analysis of XMM-Newton archival
data of 3XMM J004514.7+415035 (aka [PFH2005] 622, Pietsch et al. 2005, ApJ
434, 483), the candidate X-ray counterpart of GRB 150301C (aka Swift
J0045.2+4151, GCN Circ 17512, 17516, 17536, 17544). The source is detected
by the EPIC instrument at a 0.2-12 keV flux level of ~10^-14 erg/cm^2/s in
two observations (2002-01-26 and 2007-01-05), while only upper limits of
~5x10^-14 erg/cm^2/s can be set from 5 shorter observations performed in
July 2006. Shallow upper limits of ~10^-12 erg/cm^2/s can be derived from
three non-detections during slew observations on 2005-07-03, 2007-01-06,
and 2010-01-31.
The EPIC light curves of the two observations show no evidence for
variability. The search for coherent pulsations in the PN data, between
0.15 and 10^4 s, gives negative results. The blind search for transients
does not report any significant candidates within the BAT error circle of
GRB 150301C in any of the seven XMM-Newton observations.
We extracted the EPIC spectra of 3XMM J004514.7+415035 and, after
verifying that there are no significant spectral differences between the
two observations, we fit them simultaneously with an absorbed power-law
model. The best-fit parameters (errors at the 90% confidence level) are
N_H<3x10^21 cm^-2 and photon index 1. 9 (-0.6, +0.8). Fixing the N_H to
the Galactic value of 10^21 cm^-2, as appropriate for sources in the M31
disk, the photon index can be constrained in the 1.6-2.2 range (C-stat=142
for 143 degrees of freedom) and the unabsorbed flux in the 0.1-10 keV
range is (1.3 +/- 0.3) x10^-14 erg/cm^2/s, corresponding to ~6x10^35 erg/s
at the M31 distance.
We note that the properties of 3XMM J004514.7+41503 are consistent with
those of an active magnetar, like, e.g., SGR1806-20, at the distance of
M31. Considering that the duration, fluence and spectrum of the burst
detected by BAT are compatible with an intermediate flare from a magnetar
in M31, 3XMM J004514.7+41503 might be considered as a magnetar candidate
in the Andromeda galaxy.
Plots of the long term flux evolution, the background-subtracted and
exposure-corrected light curves, and the power density spectra with pulsed
fraction upper limits can be found on the EXTraS website:
http://www.extras-fp7.eu/index.php/home/90-extras/news/158-gcn-atel-1
EXTraS ("Exploring the X-ray Transient and variable Sky") is a project
aimed at the systematic exploitation of the XMM/EPIC database, to search
for, and characterize variability (both periodic and aperiodic), to search
for new transients and to provide a phenomenological classification of
variable sources. All EXTraS results, products and tools will be released
to the community at the end of the project. EXTraS is carried out by a
collaboration including INAF (Italy), IUSS (Italy), CNR/IMATI (Italy),
University of Leicester (UK), MPE (Germany) and ECAP (Germany) and has
been funded within the EU-FP7 framework (grant agreement n. 607452).
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