GRB 160225A
GCN Circular 19102
Subject
GRB 160225A: TSHAO optical afterglow detection
Date
2016-02-27T21:44:21Z (10 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), A. Kusakin (Fesenkov Astrophysical Institute), I. Reva
(Fesenkov Astrophysical Institute), A. Volnova (IKI), A. Pozanenko (IKI)
report on behalf of larger GRB follow-up collaboration:
We observed the Swift GRB 160225A (Siegel et al., GCN 19075) with
Zeiss-1000 (West, East) 1-m telescopes of Tien Shan Astronomical
Observatory. We obtained several images in R filter starting on Feb. 25
(UT) 14:45:56. In the first images we do not detect any optical source
(Mazaeva et al., GCN 19078). In combine images we detect afterglow
(Yoshiiet al., GCN 19080; Kuroda al., GCN 19081; Wiersema al., GCN
19082). Preliminary photometry of combined images is following
Date UT start t-T0 Filter Exp. OT Err. UL
(mid, days) (s)
*2016-02-25 14:45:56 0.07022 R 87*90 20.75 0.16 21.4
2016-02-25 15:30:59 0.09576 R 77*90 21.36 0.20 21.9
2016-02-25 17:58:10 0.18146 R 52*90 n/d n/a 21.7
*) Zeiss-1000 West telescope observations
Photometry is based on SDSS-DR9 nearby stars
SDSS-DR9_id R(Lupton)
J105614.20+533500.1 15.35
J105714.63+533304.9 14.36
J105658.91+533304.1 15.77
GCN Circular 19097
Subject
GRB 160225A: LOAO optical upper limit
Date
2016-02-27T12:16:10Z (10 years ago)
From
Soomin Jeong at IAA-CSIC <sjeong@iaa.es>
S. Jeong (SKKU/IAA-CSIC), M. Im (SNU), Y. Urata (NCU), I. H. Park (SKKU) on behalf of larger collaboration:
We observed the field of GRB 160225A (Siegel, et al., GCN 19075) with the 1m telescope of Mt. Lemmon Optical Astronomy Observatory (LOAO) in Arizona.
The series of images are taken in R filter starting on Feb. 26 02:45:36 UT (~12.4 hr post burst). We do not detect any optical afterglow candidate within the
XRT enhanced error circle (Goad et al., GCN 19077) down to the following magnitudes calibrated with the nearby USNO-B1.0 stars. The non-detection is consistent with
the previous UL report in similar epoch (Butler, et al., GCN 19088).
Mid Time Exposure Filter Magnitude
(hr) (s)
-------------------------------------------------------
12.83 9x300 R > 21.5
-------------------------------------------------------
USNO-B1.0_id R1 R2
1436-0208445 14.73 15.26 14.995
1436-0208447 13.55 13.74 13.645
GCN Circular 19093
Subject
GRB 160225A: Continued RATIR Optical and NIR Observations
Date
2016-02-26T16:52:29Z (10 years ago)
From
Nat Butler at Az State U <natbutler@asu.edu>
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William
H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier
Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (GSFC/STScI),
Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC),
Jos�� A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes��s Gonz��lez (UNAM),
Carlos Rom��n-Z����iga (UNAM), Neil Gehrels (GSFC), Harvey Moseley (GSFC),
John Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:
We observed the field of GRB 160225A (Siegel, et al., GCN 19075) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the
1.5m Harold Johnson Telescope at the Observatorio Astron��mico Nacional on
Sierra San Pedro M��rtir from 2016/02 26.13 to 2016/02 26.51 UTC (12.72 to
21.97 hours after the BAT trigger), obtaining a total of 6.38 hours
exposure in the r and i bands and 2.68 hours exposure in the Z, Y, J, and H
bands.
With continued exposure (see, Butler, et al., GCN 19088), we now detect the
WHT afterglow candidate (Wiersema, et al., GCN 19082) in all bands. In
comparison with the SDSS DR9 and 2MASS catalogs, we find:
r = 23.84 +/- 0.18
i = 23.13 +/- 0.11
Z = 22.71 +/- 0.18
Y = 22.40 +/- 0.22
J = 22.44 +/- 0.26
H = 22.04 +/- 0.26
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.
We have fitted our photometry with a power-law source and redshifted Milky
Way, LMC, or SMC extinction laws and IGM extinction (see, Littlejohns, et
al. 2014). The detection in r conclusively rules out solutions with z > 5.
However, there are a range of solutions up to z ~ 4.5.
We thank the staff of the Observatorio Astron��mico Nacional in San Pedro
M��rtir.
GCN Circular 19091
Subject
GRB 160225A: Swift-BAT refined analysis
Date
2016-02-26T15:16:08Z (10 years ago)
From
Takanori Sakamoto at AGU <tsakamoto@phys.aoyama.ac.jp>
D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU),
M. H. Siegel (PSU), M. Stamatikos (OSU), 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 160225A (trigger #675998)
(Siegel, et al., GCN Circ. 19075). The BAT ground-calculated position is
RA, Dec = 164.217, 53.659 deg which is
RA(J2000) = 10h 56m 52.1s
Dec(J2000) = +53d 39' 33.6"
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 35%.
The mask-weighted light curve shows a multiple peak structure starting
at T0-30 sec and ending at T0+50 sec. Although there is a hint of
a emission after T0+100 sec, no data are available after T0+150 sec because
the spacecraft slewed away to the GRB. T90 (15-350 keV) is 157 +- 70 sec
(estimated error including systematics).
The time-averaged spectrum from T-30.38 to T+135.29 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.55 +- 0.23. The fluence in the 15-150 keV band is 1.6 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+37.13 sec in the 15-150 keV band
is 1.0 +- 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/675998/BA/
GCN Circular 19089
Subject
GRB 160225A: MASTER-Amur observations
Date
2016-02-26T09:27:38Z (10 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
N.Tyurina, E. Gorbovskoy, V. Lipunov, V.Kornilov, P.Balanutsa,
A.Kuznetsov, D.Kuvshinov
Lomonosov Moscow State University,
Sternberg Astronomical Institute, Moscow State University
A.Gabovich, V.Yurkov, Yu.Sergienko, D.Varda
Blagoveschensk Educational State University, Blagoveschensk
D.Buckley, S. Potter, M.Kotze
South African Astronomical Observatory
K.Ivanov, N.M.Budnev, O.Gres, V.A.Poleshchuk
Irkutsk State University
A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory
R. Rebolo, M. Serra-Ricart, N. Lodieu, G. Israelian
The Instituto de Astrofisica de Canarias
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru)
located in Blagoveschensk was pointed to the GRB160225A 20 sec after
notice time and 204 sec after Swift BAT trigger (Siegel et al, 19075)
time at 2016-02-25 14:24:20 UT (Gabovich et al, 19076).
We did not see any OT brighter 2-sigma. Our unfiltered camera sensitive up
to 10 mk.
Id t_start-t_trigger t_mean-t_trig Exp.time Limit
s s s unfiltered
767291 204 224 40 17.4
767293 256 281 50 17.6
767295 318 348 60 17.0
769139 318 768 600 18.7
769244 318 1187 1200 19.0
Our unfiltered magnitude calibrated to USNOB1 stars as m =0.2B + 0.8R .
The message may be cited.
GCN Circular 19088
Subject
GRB 160225A: RATIR Optical and NIR Observations
Date
2016-02-26T07:25:27Z (10 years ago)
From
Nat Butler at Az State U <natbutler@asu.edu>
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William
H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier
Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (GSFC/STScI),
Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC),
Jos�� A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes��s Gonz��lez (UNAM),
Carlos Rom��n-Z����iga (UNAM), Neil Gehrels (GSFC), Harvey Moseley (GSFC),
John Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:
We observed the field of GRB 160225A (Siegel, et al., GCN 19075) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the
1.5m Harold Johnson Telescope at the Observatorio Astron��mico Nacional on
Sierra San Pedro M��rtir from 2016/02 26.13 to 2016/02 26.28 UTC (12.72 to
16.34 hours after the BAT trigger), obtaining a total of 2.47 hours
exposure in the r and i bands and 1.04 hours exposure in the Z, Y, J, and H
bands.
We detect the WHT afterglow candidate (Wiersema, et al., GCN 19082), and
find it to have faded. In comparison with the SDSS DR9 and 2MASS catalogs,
we obtain the following detections and upper limits (3-sigma):
r > 24.09
i = 23.03 +/- 0.16
Z = 22.17 +/- 0.19
Y > 22.35
J = 22.06 +/- 0.33
H > 21.74
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB. The r-band faintness suggests that
this may be a moderate to high-z source. Fitting Milky Way, LMC, and SMC
Exctinction Laws in Addition to the IGM (see, Littlejohns, et al. 2014), we
find a photo-z of 5.54 (+0.35,-5.11; 90% conf.). Hence, a high-z solution
is preferred, but a low-z origin is not ruled out.
We thank the staff of the Observatorio Astron��mico Nacional in San Pedro
M��rtir.
GCN Circular 19087
Subject
GRB 160225A: Swift/UVOT Upper Limits
Date
2016-02-26T05:10:10Z (10 years ago)
From
Mike Siegel at PSU/Swift MOC <siegel@swift.psu.edu>
M. H. Siegel (PSU) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 160225A
839 s after the BAT trigger (Siegel et al., GCN Circ. 19075).
No optical afterglow consistent with the XRT position
(Goad et al. GCN Circ. 19077) or the previously reported
optical position (Wierema, et al., GCN Circ. 19082)
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 839 989 147 >20.7
white 839 2657 342 >21.1
v 1121 2708 194 >19.9
b 1047 2632 194 >20.8
u 1022 2608 156 >19.9
w1 998 3036 311 >20.1
m2 1494 2912 236 >20.2
w2 1446 2683 78 >20.0
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 19086
Subject
GRB 160225A: Xinglong TNT optical observation
Date
2016-02-26T03:35:09Z (10 years ago)
From
L.P. Xin at NAOC <xlp@bao.ac.cn>
L. P. Xin, X. F. Wang, J. Y. Wei, X. H. Han, Y. L. Qiu,
J. Wang, C. Wu, J. S. Deng report:
We observed GRB 160225A (Siegel et al. GCN 19075) with
80cm TNT telescope, located at Xinglong obervatory, China,
at 14:24:26 UT, about 3.5 min after the burst.
The optical afterglow (Wiersema et al., GCN 19082) near the
enhanced XRT errorbox (Goad et al., GCN 19082) was detected
in our white and R-band images.
The brightness of the optical afterglow is about 17.58 mag
at the mid time of 3.67 min afer the burst, calibrated by
the USNO B1.0 star (RA=10:56:59.4 DEC=+53:40:45 R2=15.26mag).
We thank excellent support of the Xinglong 80cm TNT staff,
particularly YunPeng Wang.
The message may be cited.
GCN Circular 19084
Subject
GRB 160225A: Swift-XRT refined Analysis
Date
2016-02-26T02:36:49Z (10 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
J.A. Kennea (PSU), K.L. Page (U. Leicester), C. Pagani (U. Leicester),
A.P. Beardmore (U. Leicester), A. D'Ai (INAF-IASFPA), A. Maselli
(INAF-IASFPA), A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU),
D.N. Burrows (PSU) and M.H. Siegel report on behalf of the Swift-XRT
team:
We have analysed 9.4 ks of XRT data for GRB 160225A (Siegel et al. GCN
Circ. 19075), from 841 s to 31.8 ks after the BAT trigger. The data
are entirely in Photon Counting (PC) mode. The enhanced XRT position
for this burst was given by Goad et al. (GCN Circ. 19077).
The light curve can be modelled with a power-law decay with a decay
index of alpha=0.91 (+/-0.06).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.11 (+/-0.14). The
best-fitting absorption column is 5.7 (+3.0, -2.7) x 10^20 cm^-2, in
excess of the Galactic value of 9.7 x 10^19 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 (3.6 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 5.7 (+3.0, -2.7) x 10^20 cm^-2
Galactic foreground: 9.7 x 10^19 cm^-2
Excess significance: 2.9 sigma
Photon index: 2.11 (+/-0.14)
If the light curve continues to decay with a power-law decay index of
0.91, the count rate at T+24 hours will be 0.013 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.9 x
10^-13 (4.5 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00675998.
This circular is an official product of the Swift-XRT team.
GCN Circular 19083
Subject
GRB 160225A: NOT optical observations
Date
2016-02-26T02:10:23Z (10 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
D. Xu (NAOC/CAS), D. Malesani (DARK/NBI), N. Tanvir (U. of Leicester),
A. Kvammen (NOT) report on behalf of a large collaboration:
We observed the field of GRB 160225A (Siegel et al. GCN 19075) using the
2.56m Nordic Optical Telescope (NOT) equipped with the ALFOSC camera.
Observations started at 23:31:27 UT on 2016-02-25 (i.e., 8.56 hr
post-burst) and 9x200s exposures were obtained in the Sloan r- and
i-band, respectively.
The optical afterglow is detected at the WHT position (Wiersema et al.,
GCN 19082) and presumably also the MITSuME position (Yoshii et al. GCN
19080). We measured m(r)=23.25 +/- 0.15 at 8.86 hr post-burst and m(i) =
22.55 +/- 0.07 at 9.48 hr post-burst, calibrated with nearby SDSS stars.
GCN Circular 19082
Subject
GRB 160225A: WHT LIRIS observations
Date
2016-02-26T00:01:37Z (10 years ago)
From
Klaas Wiersema at U Leicester <kw113@leicester.ac.uk>
K. Wiersema, N. Tanvir (U. of Leicester), A. Levan (U. of Warwick)
and G. Pugliese (API/UvA) report:
We observed the position of GRB 160225A (Siegel et al. GCN 19075) with
the 4.2m William Herschel Telescope (WHT). Using the LIRIS instrument
we obtained 20x60 sec in Y band, 20x60 sec in J band and 60x20 sec in Ks band.
Observations started at 19:57 UT on 25 February 2016 (i.e. 5.62 hours after
burst).
A point source is clearly detected near the enhanced XRT position
(Goad et al. GCN 19077), at position:
RA (J2000): 10 56 55.18
Dec (J2000): +53 40 13.7
with an uncertainty of 0.5 arc seconds. The source is seen in all three
filters, and has magnitudes J~20.6 mag and Ks~19.2 mag (Vega magnitudes,
calibrated using 2MASS objects in the field).
We acknowledge excellent support from Raine Karjalainen (ING).
GCN Circular 19081
Subject
GRB 160225A: MITSuME Okayama Optical Observation
Date
2016-02-25T23:50:50Z (10 years ago)
From
Daisuke Kuroda at OAO/NAOJ <dikuroda@oao.nao.ac.jp>
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 160225A (Siegel et al., GCNC 19075)
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 2016-02-25 14:26:51 UT (~5.9 min after
the burst). We detected the previously reported afterglow (Yoshii
et al., GCNC 19080) in Rc and Ic bands.
Photometric results and three sigma upper limit of the OT are
listed below. We used SDSS-DR7 catalog for flux calibration.
#T0+[day] MID-UT T-EXP[sec] g' Rc Rc_err Ic Ic_err
------------------------------------------------------------------
0.00777 14:32:08 540.0 >19.4 18.6 0.2 17.8 0.2
------------------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
GCN Circular 19080
Subject
GRB 160225A: MITSuME Akeno Optical Observation
Date
2016-02-25T17:53:11Z (11 years ago)
From
Taketoshi Yoshii at Tokyo Tech <yoshii.t.ac@m.titech.ac.jp>
T. Yoshii, Y.Saito, T.Fujiwara, Y. Tachibana,
Y.Ono, S.Harita, Y.Muraki, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:
We searched for the optical counterpart of GRB 160225A (M. H. Siegel et al., GCN
Circular #19075) 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 2016-01-04 14:24:14 UT (198 sec after the burst) and
we detected the optical counterpart in Rc and Ic band.
The measured magnitudes were listed as follows.
We obtained following limits for the magnitudes.
T0+[sec] MID-UT T-EXP[sec] g' Rc Ic
-------------------------------------------------------------------------------------------------------
378 14:27:14 270 > 19.4 18.2 +/- 0.1 17.1 +/- 0.2
-------------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
GCN Circular 19078
Subject
GRB 160225A: TSHAO optical upper limit
Date
2016-02-25T17:37:58Z (11 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), A. Kusakin (Fesenkov Astrophysical Institute), I.
Reva (Fesenkov Astrophysical Institute), A. Volnova (IKI), A. Pozanenko
(IKI) report on behalf of larger GRB follow-up collaboration:
We observed the Swift GRB 160225A (Siegel et al., GCN 19075) with
Zeiss-1000 (West) 1-m telescope of Tien Shan Astronomical Observatory.
We obtained several images in R filter starting on Feb. 25 (UT)
14:46:05. In the first images we do not detect any optical source within
enhanced Swift-XRT position (Goad et al., GCN 19077). Preliminary
photometry of one of single 90 s image is following
Date UT start t-T0 Filter Exp. UL (3sigma)
(mid, days) (s)
2016-02-25 14:47:35 0.01903 R 1*90 18.90
GCN Circular 19077
Subject
GRB 160225A: Enhanced Swift-XRT position
Date
2016-02-25T17:22:20Z (11 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester)
report on behalf of the Swift-XRT team.
Using 2168 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 160225A, 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 = 164.22971, +53.66998 which is equivalent
to:
RA (J2000): 10h 56m 55.13s
Dec (J2000): +53d 40' 11.9"
with an uncertainty of 1.7 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 19076
Subject
GRB 160225A: MASTER-Amur early observations
Date
2016-02-25T14:47:57Z (11 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
A.Gabovich, V.Yurkov, Yu.Sergienko, D.Varda
Blagoveschensk Educational State University, Blagoveschensk
E. Gorbovskoy, N.Tyurina, V. Lipunov, V.Kornilov,
P.Balanutsa, A.Kuznetsov, D.Kuvshinov
Lomonosov Moscow State University,
Sternberg Astronomical Institute, Moscow State University
D.Buckley, S. Potter, M.Kotze
South African Astronomical Observatory
K.Ivanov, N.M.Budnev, O.Gres, V.A.Poleshchuk
Irkutsk State University
A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory
R. Rebolo, M. Serra-Ricart, N. Lodieu, G. Israelian
The Instituto de Astrofisica de Canarias
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru)
located in Blagoveschensk was pointed to the GRB160225A 20 sec after
notice time and 204 sec after Swift BAT trigger time at 2016-02-25
14:24:20 UT (Siegel et al, 19075). On
our first (40s exposure) set we haven`t found optical transient within
SWIFT error-box (ra=10 56 58 dec=+53 39 17 r=0.050000).
The 5-sigma upper limit has been about 17.5 mag
The message may be cited.
GCN Circular 19075
Subject
GRB 160225A: Swift detection of a burst
Date
2016-02-25T14:42:58Z (11 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
M. H. Siegel (PSU), A. P. Beardmore (U Leicester),
P.A. Evans (U Leicester), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU),
N. P. M. Kuin (UCL-MSSL), L. M. McCauley (PSU),
K. L. Page (U Leicester), D. M. Palmer (LANL),
T. G. R. Roegiers (PSU), T. Sakamoto (AGU),
B. Sbarufatti (INAF-OAB/PSU) and T. N. Ukwatta (LANL) report on behalf
of the Swift Team:
At 14:20:56 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 160225A (trigger=675998). Swift's slew was briefly
delayed due to an observing constraint.
The BAT on-board calculated location is
RA, Dec 164.242, +53.655 which is
RA(J2000) = 10h 56m 58s
Dec(J2000) = +53d 39' 19"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed multiple spikes
over a 50 second interval. The peak count rate
was ~1500 counts/sec (15-350 keV) at ~3 sec after the trigger.
The XRT began observing the field at 14:34:50.6 UT, 834.2 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 164.22846, 53.66991 which is equivalent
to:
RA(J2000) = 10h 56m 54.83s
Dec(J2000) = +53d 40' 11.7"
with an uncertainty of 3.8 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 in excess of the Galactic value (9.69 x
10^19 cm^-2, Willingale et al. 2013), with an excess column of 3.8
(+4.26/-3.38) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 839 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 expected extinction corresponding to E(B-V) of
0.01.
Burst Advocate for this burst is M. H. Siegel (siegel AT swift.psu.edu).
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.)