GRB 160525B
GCN Circular 19564
Subject
GRB 160525B: 15 GHz upper limits from AMI
Date
2016-06-24T12:53:04Z (9 years ago)
From
Kunal Mooley at Oxford U <kunal.mooley@physics.ox.ac.uk>
K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), G. E. Anderson
(Curtin), T. Cantwell (Manchester), C. Rumsey, D. Titterington, S.
Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge),
K. Grainge, A. Scaife (Manchester)
The AMI Large Array robotically triggered on the Swift alert for GRB
160525B (Krimm et al., GCN 19459) as part of the 4pisky program, and
subsequent follow up observations were obtained up to 10 days
post-burst. Our observations at 15 GHz on 2016 May 25.55, May 26.66, May
28.66, and May 31.68 (UT) do not reveal any radio source at the XRT
location (Beardmore et al., GCN 19463), with 3sigma upper limits of 99
uJy, 63 uJy, 66 uJy, and 96 uJy respectively.
We thank the AMI staff for scheduling these observations. The AMI-GRB
database is a log of all GRB follow up observations with the AMI, and is
available at http://4pisky.org/ami-grb/.
GCN Circular 19475
Subject
GRB 160525B: MITSuME Akeno optical upper limits
Date
2016-05-31T10:05:57Z (10 years ago)
From
Taketoshi Yoshii at Tokyo Tech <yoshii.t.ac@m.titech.ac.jp>
K. Saisho, Y. Muraki, Y. Ono, T. Fujiwara, T. Yoshii, Y. Saito, Y. Tachibana,
H. Ohuchi, Y. Yano, S. Harita, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:
We searched for the optical counterpart of GRB 160525B (H. A. Krimm et al., GCN Circular #19459) 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 2016-05-25 10:03:51 UT (~0.65 h after the burst).
We did not find any new point source within XRT circle in all three bands.
We obtained following limits for the magnitudes.
T0+[hour] MID-UT T-EXP[sec] g' Rc Ic
----------------------------------------------------------------------------
0.65 15:58:53 1140 >18.6 >18.2 >17.6
----------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
GCN Circular 19470
Subject
GRB 160525B: Mondy optical upper limit
Date
2016-05-26T18:08:31Z (10 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), E. Klunko (ISTP), A. Volnova (IKI), I. Korobtsev
(ISTP), A. Pozanenko (IKI) report on behalf of larger GRB follow-up
collaboration:
We observed the field of the GRB 160525B (Krimm et al., GCN 19459) with
AZT-33IK telescope of Sayan observatory (Mondy) starting on May, 25
(UT) 15:54:47. We do not detect any source within enhanced Swift-XRT
position (Beardmore et al., GCN 19463). Preliminary photometry of the
combined image is following
Date UT start t-T0 Filter Exp. UpperLimit (3 sigma)
(mid, days) (s)
2016-05-25 15:54:47 0.29111 R 30*120 22.6
Photometry is based on nearby SDSS-DR9 stars, Lupton transformations into R:
SDSS-DR9_id R(Lupton)
J095742.79+511301.4 16.17
J095737.78+511402.4 16.43
J095736.76+511019.5 14.87
J095730.61+510914.1 17.74
J095737.35+510856.0 15.01
GCN Circular 19469
Subject
GRB 160525B: Khureltogot optical upper limit
Date
2016-05-26T18:06:16Z (10 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), S. Schmalz (ISON), A. Volnova (IKI), N. Tungalag
(Research Center of Astronomy and Geophysics MAS), I. Molotov (KIAM),
A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of the GRB 160525B (Krimm et al., GCN 19459) with
ORI-40 telescope of Khureltogot observatory starting on May, 25 (UT)
15:51:26. We do not detect any source within enhanced Swift-XRT
position (Beardmore et al., GCN 19463). Preliminary photometry of the
combined image is following
Date UT start t-T0 Filter Exp. UpperLimit (3 sigma)
(mid, days) (s)
2016-05-25 15:51:26 0.29070 clear 60*60 21.0
Photometry is based on nearby SDSS-DR9 stars, Lupton transformations into R:
SDSS-DR9_id R(Lupton)
J095742.79+511301.4 16.17
J095737.78+511402.4 16.43
J095736.76+511019.5 14.87
J095730.61+510914.1 17.74
J095737.35+510856.0 15.01
GCN Circular 19468
Subject
GRB 160525B: Swift-BAT refined analysis
Date
2016-05-26T04:07:57Z (10 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
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. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 160525B (trigger #687522)
(Krimm, et al., GCN Circ. 19459). The BAT ground-calculated position is
RA, Dec = 149.438, 51.197 deg, which is
RA(J2000) = 09h 57m 45.2s
Dec(J2000) = +51d 11' 48.9"
with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 81%.
The mask-weighted light curve shows weak emission starting at ~T-1 sec,
the main emission from ~T0 to ~T+0.3 sec, and weak emission out to ~T+0.6 sec.
T90 (15-350 keV) is 0.29 +- 0.05 sec (estimated error including systematics).
The time-averaged spectrum from T+0.02 to T+0.33 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.89 +- 0.35. The fluence in the 15-150 keV band is 3.2 +- 0.8 x 10^-8 erg/cm2.
The 1-sec peak photon flux measured from T-0.32 sec in the 15-150 keV band
is 0.9 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/687522/BA/
GCN Circular 19467
Subject
GRB 160525B: Swift-XRT refined Analysis
Date
2016-05-25T21:57:33Z (10 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Maselli (INAF-IASFPA),
L.M. McCauley (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU),
C. Pagani (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U.
Leicester) and H.A. Krimm report on behalf of the Swift-XRT team:
We have analysed 6.3 ks of XRT data for GRB 160525B (Krimm et al. GCN
Circ. 19459), from 91 s to 18.0 ks after the BAT trigger. The data are
entirely in Photon Counting (PC) mode. The enhanced XRT position for
this burst was given by Beardmore et al. (GCN Circ. 19460).
The light curve can be modelled with a power-law decay with a decay
index of alpha=1.27 (+/-0.10).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.91 (+0.26, -0.24). The
best-fitting absorption column is 6.0 (+6.5, -5.1) x 10^20 cm^-2,
consistent with the Galactic value of 8.3 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 3.4 x 10^-11 (3.9 x
10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 6.0 (+6.5, -5.1) x 10^20 cm^-2
Galactic foreground: 8.3 x 10^19 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.91 (+0.26, -0.24)
If the light curve continues to decay with a power-law decay index of
1.27, the count rate at T+24 hours will be 2.6 x 10^-4 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.8 x
10^-15 (10.0 x 10^-15) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00687522.
This circular is an official product of the Swift-XRT team.
GCN Circular 19466
Subject
GRB 160525B: Nanshan optical upper limit
Date
2016-05-25T21:32:53Z (10 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
D. Xu, Y.-H. Han (both NAOC/CAS), S.-G. Ma, A. Esamdin, J.-Z. Liu, L. Ma
(all XAO) report:
We observed the field of GRB 160525B (Krimm et al., GCN 19459) using the
1m telescope located at Nanshan, Xinjiang, China. We obtained 5x300s
R-band frames, starting at 15:26:24 UT on 2016-05-25, i.e., 6.02 hr
after the burst.
No optical source is detected at the XRT position (Beardmore et al., GCN
19463) in the stacked image, down to a limiting magnitude of m(R)>21.5,
calibrated with the nearby SDSS field.
GCN Circular 19465
Subject
GRB 160525B: Swift/UVOT Detection
Date
2016-05-25T20:09:20Z (10 years ago)
From
Massimiliano de Pasquale at IASF-Palermo <m.depasquale@ucl.ac.uk>
M. De Pasquale, N.P. Kuin (UCL-MSSL) and H. A. Krimm (CRESST/GSFC/USRA)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 160525B
88 s after the BAT trigger (Krimm et al., GCN Circ. 19459).
A source consistent with the XRT position (Evans GCN Circ. 19460)
is detected in the initial UVOT white filter exposure.
Preliminary detections and 3-sigma upper limits using the UVOT
photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early
exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 88 238 147 19.8 +/- 0.3
white 581 1894 284 >20.9
v 631 1945 156 >18.9
b 556 1870 136 >19.8
u 300 2018 379 >20.0
w1 680 1996 156 >19.5
m2 1603 1795 39 >18.2
w2 606 1573 58 >18.9
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).
--
Dr. Massimiliano De Pasquale
Research associate - Swift UVOT scientist
Mullard Space Science Laboratory, University College London
GCN Circular 19463
Subject
GRB 160525B: Enhanced Swift-XRT position
Date
2016-05-25T15:29:40Z (10 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1923 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 160525B, 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 = 149.38464, +51.20657 which is equivalent
to:
RA (J2000): 09h 57m 32.31s
Dec (J2000): +51d 12' 23.7"
with an uncertainty of 1.6 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 19460
Subject
GRB 160525B: Prompt enhanced Swift-XRT position
Date
2016-05-25T10:50:45Z (10 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Using 1.9 ks of promptly downlinked XRT event data for GRB 160525B, we
find an enhanced XRT position of the afterglow: RA, Dec: 149.3845,
51.2064 which is equivalent to:
RA (J2000) = 09 57 32.28
Dec (J2000) = +51 12 23.0
with an uncertainty of 2.1 arcseconds (radius, 90% confidence).
Analysis of the promptly available data is online at
http://www.swift.ac.uk/sper/687522.
Position enhancement is is described by Goad et al. (2007, A&A, 476,
1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular is an official product of the Swift-XRT team.
GCN Circular 19459
Subject
GRB 160525B: Swift detection of a burst
Date
2016-05-25T09:34:47Z (10 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
H. A. Krimm (CRESST/GSFC/USRA), S. D. Barthelmy (GSFC),
A. D'Ai (INAF-IASFPA), P.A. Evans (U Leicester), C. Gronwall (PSU),
F. E. Marshall (NASA/GSFC), A. Maselli (INAF-IASFPA),
K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of
the Swift Team:
At 09:25:07 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 160525B (trigger=687522). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 149.443, +51.180 which is
RA(J2000) = 09h 57m 46s
Dec(J2000) = +51d 10' 49"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows a single peak
structure with a duration of about 10 sec. The peak count rate
was ~1500 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 09:26:31.0 UT, 83.4 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 149.38688, 51.20658 which is equivalent
to:
RA(J2000) = 09h 57m 32.85s
Dec(J2000) = +51d 12' 23.7"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 158 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. No spectrum from the promptly downlinked
event data is yet available to determine the column density.
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 88 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 none of
the XRT error circle. 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 H. A. Krimm (hans.krimm 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.)