GRB 180514A
GCN Circular 22723
Subject
GRB 180514A: Swift detection of a burst
Date
2018-05-14T13:48:36Z (7 years ago)
From
Boris Sbarufatti at PSU <bxs60@psu.edu>
S. J. LaPorte (PSU), A. P. Beardmore (U Leicester),
A. A. Breeveld (UCL-MSSL), D. N. Burrows (PSU), A. Deich (PSU),
S. W. K Emery (UCL-MSSL), J.D. Gropp (PSU), A. Y. Lien (GSFC/UMBC),
F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester),
B. Sbarufatti (PSU), M. H. Siegel (PSU) and A. Tohuvavohu (PSU) report
on behalf of the Neil Gehrels Swift Observatory Team:
At 13:25:33 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 180514A (trigger=832368). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 197.401, +36.969 which is
RA(J2000) = 13h 09m 36s
Dec(J2000) = +36d 58' 10"
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 40 sec. The peak count rate
was ~1300 counts/sec (15-350 keV), at ~5 sec after the trigger.
The XRT began observing the field at 13:26:51.3 UT, 77.8 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source with an enhanced position: RA, Dec 197.3713,
36.9720 which is equivalent to:
RA(J2000) = 13h 09m 29.12s
Dec(J2000) = +36d 58' 19.3"
with an uncertainty of 3.6 arcseconds (radius, 90% containment). This
location is 86 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 1.18
x 10^20 cm^-2 (Willingale et al. 2013).
The initial flux in the 2.5 s image was 1.69e-09 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 86 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.
The first BAT Position notice identified this trigger as a transient
from a known source because of proximity with the spiral galaxy NGC
5005. However, given the separation between the XRT position and NGC
5005 (~18 arcmin) and the look of the promptly downlinked BAT and XRT
data we believe this is a GRB not associated with the foreground
galaxy.
Burst Advocate for this burst is S. J. LaPorte (extragsam AT gmail.com).
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 22725
Subject
GRB 180514A: Enhanced Swift-XRT position
Date
2018-05-14T18:22:11Z (7 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 1002 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 180514A, 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 = 197.37112, +36.97231 which is equivalent
to:
RA (J2000): 13h 09m 29.07s
Dec (J2000): +36d 58' 20.3"
with an uncertainty of 2.4 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 22726
Subject
GRB 180514A: Swift-XRT refined Analysis
Date
2018-05-14T21:07:55Z (7 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
A. Tohuvavohu (PSU), Z. Liu (NAOC / U. Leicester), J.P. Osborne (U.
Leicester), K.L. Page (U. Leicester), V. D'Elia (ASDC), A. D'Ai
(INAF-IASFPA), A. Melandri (INAF-OAB), S. J. LaPorte (PSU), J.A. Kennea
(PSU) and S.J. LaPorte report on behalf of the Swift-XRT team:
We have analysed 7.0 ks of XRT data for GRB 180514A (LaPorte et al. GCN
Circ. 22723), from 84 s to 18.0 ks after the BAT trigger. The data
comprise 88 s in Windowed Timing (WT) mode with the remainder in Photon
Counting (PC) mode. The enhanced XRT position for this burst was given
by Goad et al. (GCN Circ. 22725).
The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=2.4 (+0.5, -0.8). At T+135 s the decay
steepens to an alpha of 4.9 (+1.0, -0.4) before breaking again at T+414
s to a final decay with index alpha=0.38 (+0.15, -0.17).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 3.7 (+0.4, -0.3). The
best-fitting absorption column is 2.9 (+0.7, -0.6) x 10^21 cm^-2, in
excess of the Galactic value of 1.2 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 2.1 x 10^-11 (9.6 x 10^-11) erg
cm^-2 count^-1.
A summary of the WT-mode spectrum is thus:
Total column: 2.9 (+0.7, -0.6) x 10^21 cm^-2
Galactic foreground: 1.2 x 10^20 cm^-2
Excess significance: 7.0 sigma
Photon index: 3.7 (+0.4, -0.3)
If the light curve continues to decay with a power-law decay index of
0.38, the count rate at T+24 hours will be 0.011 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.3 x
10^-13 (1.1 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00832368.
This circular is an official product of the Swift-XRT team.
GCN Circular 22727
Subject
GRB 180514A: Swift-BAT refined analysis
Date
2018-05-14T21:14:51Z (7 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
H. A. Krimm (NSF/USRA), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), S. J. LaPorte (PSU),
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-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 180514A (trigger #832368)
(LaPorte et al., GCN Circ. 22723). The BAT ground-calculated position is
RA, Dec = 197.382, 36.970 deg which is
RA(J2000) = 13h 09m 31.7s
Dec(J2000) = +36d 58' 13.0"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 91%.
The mask-weighted light curve shows a weak pulse that starts at ~T-8 s,
peaks at ~T0, and ends at ~T+55 s. T90 (15-350 keV) is 46.9 +- 14.5 sec
(estimated error including systematics).
The time-averaged spectrum from T-8.33 to T+54.71 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.77 +- 0.14. The fluence in the 15-150 keV band is 1.0 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+0.23 sec in the 15-150 keV band
is 0.7 +- 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/832368/BA/
GCN Circular 22728
Subject
GRB 180514A: GOTO Optical Observations
Date
2018-05-14T21:46:20Z (7 years ago)
From
Ben Gompertz at U of Warwick <b.gompertz@warwick.ac.uk>
B.Gompertz (U. Warwick), K.Ulaczyk (U. Warwick), M.Dyer (U. Sheffield),
E.Rol (Monash U.), K. Ackley (Monash U.), D.Steeghs (U. Warwick),
D.Galloway (Monash U.), G.Ramsay (Armagh O.),��V.Dhillon (U. Sheffield),
P.O'Brien (U. Leicester), S.Poshyachinda (NARIT), D.Pollacco (U.
Warwick), E.Thrane (Monash U.)
report on behalf of the GOTO collaboration:
The Gravitational-wave Optical Transient Observer observed the field of
GRB 180514A (trigger=832368, LaPorte et al. GCN Circ. 22723) from Roque
de los Muchachos Observatory beginning at 2018-05-14T21:09:12 UT, 7.73
hours since burst, in several wide-band filters.
In a combined L-band image (400-700nm passband), with a total exposure
time of 360s, we do not detect any optical source within the enhanced
XRT error circle (Goad et al., GCN Circ. 22725) down to a 5-sigma
limiting magnitude of V > 20.7��based on a comparison to APASS V-band
calibrators.
Further observations are planned.
GOTO is operated at the La Palma observing facilities of the University
of Warwick on behalf of a consortium including the University of
Warwick, Monash University, Armagh Observatory, the University of
Leicester, the University of Sheffield, the National Astronomical
Research Institute of Thailand (NARIT) and the Instituto de Astrofisica
de Canarias (IAC)
https://goto-observatory.org/
GCN Circular 22729
Subject
GRB 180514A: 1.5m OSN optical observations
Date
2018-05-14T22:10:10Z (7 years ago)
From
Antonio de Ugarte Postigo at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), D. A. Kann, L. Izzo, C. C. Thoene (all HETH/IAA-CSIC), and A. Sota (IAA-CSIC) report:
We have observed the field of GRB 180514A (LaPorte et al. GCN 22723) with the 1.5m telescope at the Sierra Nevada Observatory (Granada, Spain). Observations started at 20:50 UT (7.41 hr after the burst) and consisted of multiple 300 s exposures in the Ic-band.
No object is detected within the XRT error circle in the first combined 10 x 300 s exposure, which has been obtained at average time of 7.87 hr after the burst, down to a 3-sigma limit of Ic (AB) > 21.5 mag, as compared with SDSS DR14 field stars.
GCN Circular 22731
Subject
GRB 180514A: Detection limits from 2.5m NOT
Date
2018-05-15T01:04:01Z (7 years ago)
From
Antonio de Ugarte Postigo at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), D. Malesani (DAWN/NBI and DARK/NBI), P. Montanes-Rodriguez (IAC), and P. Sorensen (NOT) report:
We observed the field of GRB 180514A (LaPorte et al. GCN 22723) with the 2.5 m Nordic Optical Telescope (NOT) equipped with AlFOSC. The observation consisted of 3x300s exposures in r-band and 5x200s in z-band. The integrations started at 23:22 UT, 9.95 hr after the burst.
No credible counterpart is detected in any of the two bands within the XRT error box. For the r-band image we derive a 3-sigma limit of r > 23.8 mag, calibrated with respect to SDSS field stars.
GCN Circular 22732
Subject
GRB 180514A: MITSuME Akeno optical upper limits
Date
2018-05-15T01:05:34Z (7 years ago)
From
Ryosuke Itoh at Tokyo Institute of Tech. <itoh@hp.phys.titech.ac.jp>
R. Itoh, K. L. Murata, Y. Tachibana, S. Harita, K. Morita, T. Ozawa, H. Mamiya,
K. Shiraishi, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:
We searched for the optical counterpart of GRB 180514A
(LaPorte et al., GCN Circular #22723)
with the optical three color (g', Rc, and Ic) CCD cameras attached to
the MITSuME 50cm telescope of Akeno Observatory, Yamanashi, Japan.
The observation started on 2018-05-14 13:39:12 UT.
We did not find any point source at the position of the XRT error
circle in all three bands. We obtained following limits for the magnitudes.
T0+[min] MID-UT T-EXP[sec] g' Rc Ic
-------------------------------------------------------------------------------------------------------
~13.6 14:18:59 4,200 >18.7 >19.2 >18.1
-------------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used UCAC-4 catalog for flux calibration.
GCN Circular 22733
Subject
GRB 180514A: Swift/UVOT Upper Limits
Date
2018-05-15T06:58:41Z (7 years ago)
From
Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk>
A. A. Breeveld (UCL-MSSL) and S. J. LaPorte (PSU) report on behalf of
the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 180514A 87
s after the BAT trigger (LaPorte et al., GCN Circ. 22723).
No optical afterglow consistent with the enhanced XRT position (Goad et
al. GCN Circ. 22725) 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 87 237 147 >20.8
u_FC 300 549 246 >20.2
white 87 7353 688 >22.8
v 6129 6329 197 >20.1
b 5513 7148 393 >20.7
u 300 6943 639 >21.6
w1 5104 6739 393 >20.8
m2 6334 6533 197 >20.1
w2 5924 7540 374 >20.3
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 22735
Subject
GRB 180514A: CrAO/ZTSH optical observations and afterglow candidate
Date
2018-05-16T17:41:55Z (7 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Volnova (IKI), V. Rumyantsev (CrAO), A. Pozanenko (IKI), E.
Mazaeva (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of the GRB 180514A (LaPorte et al., GCN 22723)
with ZTSH 2.6m telescope of CrAO observatory starting on May 14 (UT)
18:16:14. We took several images in filter R with exposures of 120 s. We
detect one object within enhanced XRT (Goad et al., GCN 22725). The
coordinates of the object are (J2000) 13 09 29.01 +36 58 19.5 with
uncertainty of 0.3 arcsec in each coordinate.
Preliminary photometry of the object in a combined image is following
UT start t-T0 Filter Exp. OT err UL(3sigma)
(mid, days) (s)
2018-05-14 19:07:44 0.23321 R 36*120 22.90 0.07 23.9
The photometry is based on nearby SDSS stars:
SDSS-DR9_id R(Lupton)
J130934.98+365851.3 18.625 0.020
J130931.60+365838.3 18.933 0.023
J130931.36+365901.6 19.497 0.048
Based only on our observation we can not say about variability the
object. However taking into account deep upper limit of NOT observation
at 9.95 hrs (A. de Ugarte Postigo et al., GCN 22731) we can suggest that
the object is the afterglow of GRB 180514A.
The finding chat can be found in
http://grb.rssi.ru/GRB180514A/GRB180514A_ZTSh_fc.png
GCN Circular 22736
Subject
GRB 180514A: MITSuME Ishigakijima optical upper limits
Date
2018-05-17T01:11:15Z (7 years ago)
From
Ryosuke Itoh at Tokyo Institute of Tech. <itoh@hp.phys.titech.ac.jp>
T. Horiuchi, H. Hanayama, M. Honma (IAO, NAOJ),
R. Itoh, K. L. Murata, Y. Tachibana, S. Harita, K. Morita, T. Ozawa, H. Mamiya,
K. Shiraishi, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:
We searched for the optical counterpart of GRB 180514A
(LaPorte et al., GCN Circular #22723, Volnova et al., GCN Circular #22735)
with the optical three color (g', Rc, and Ic) CCD cameras attached to
the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory.
The observation started on 2018-05-14 13:46:55 UT.
We did not find any point source at the position of the XRT error
circle in all three bands. We obtained following limits for the magnitudes.
T0+[min] MID-UT T-EXP[sec] g' Rc Ic
-------------------------------------------------------------------------------------------------------
~21.4 14:18:37 3,300 >19.6 >19.2 >17.2
-------------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used UCAC-4 catalog for flux calibration.