GRB 180715A
GCN Circular 23217
Subject
GRB 180715A: 15 GHz upper limits from the AMI Short GRB Program
Date
2018-09-10T06:54:19Z (7 years ago)
From
Kunal Mooley at NRAO,Caltech <kmooley@caltech.edu>
J. Bright (Oxford), K. P. Mooley (NRAO, Caltech; Jansky Fellow), R. P.
Fender (Oxford)
We observed the field of short GRB 180718A (Ukwatta et al., GCN 22947)
with the AMI Large Array at 15 GHz. Our observations on 2018 Jul 16.80,
Jul 17.73, Jul 19.80 and Jul 23.80 (UT) (1.05 d, 1.98 d, 4.05 d and 7.05
d post-burst) does not reveal any potential afterglow candidate
consistent with the BAT location (Ukwatta et al., GCN 22947), and our
3sigma upper limit to the flux density are 137 uJy, 186 uJy, 106 uJy and
146 uJy respectively.
We thank the MRAO staff for scheduling these observations. Results from
the AMI Short GRB program are posted on the AMI-GRB database available
at http://4pisky.org/ami-grb/.
GCN Circular 23059
Subject
GRB 180715A: CALET CAL gamma-ray analysis
Date
2018-07-30T09:50:27Z (7 years ago)
From
Takanori Sakamoto at AGU <tsakamoto@phys.aoyama.ac.jp>
N. Cannady (LSU), K. Yoshikawa, Y. Asaoka (Waseda U),
A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita, Y. Kawakubo,
A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU),
S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU), S. Ricciarini (U of Florence),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:
Using the CALET CALorimeter (CAL) data, we report GeV gamma-ray search
analysis associated to GRB 180715A (Ukwatta, et al., GCN Circ. 22947, 22951;
Hamburg and Meegan, GCN Circ. 22952; Torii et al., GCN Circ. 22956)
The CAL was operating in low energy trigger mode at the trigger time of
the CALET Gamma-ray Burst Monitor (CGBM). We have searched for
gamma-ray events in the 1-10 GeV band from -60 sec to +60 sec from
the CGBM trigger time using the Swift-BAT position (Ukwatta et al.
GCN Circ. 22951) and found no candidates. The 90% upper limit of CAL is
3.2e-7 erg/cm2/s (1-10 GeV) assuming a power-law spectrum of a photon
index of -2.
All the quoted values are preliminary.
GCN Circular 23012
Subject
GRB 180715A: AstroSat CZTI detection
Date
2018-07-22T14:53:11Z (7 years ago)
From
Vidushi Sharma at IUCAA <vidushi@iucaa.in>
V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:
Analysis of Astrosat CZTI data showed the detection of a GRB 180715A, which was also detected by Swift (Palmer D. et al., GCN 22947), Fermi-GBM (Hamburg R. et. al., GCN 22952) and CALET (Torii S. et al.,GCN 22956).
The source was clearly detected in the 40-200 keV energy range. The light curve shows a single peak of emission with peak at 18:06:59.5 UT. The measured peak count rate is 403.6 cts/s above the background in combined data of four quadrants, with a total of 408 cts. The local mean background count rate was 476.4 cts/s. Using cumulative rates, we measure a T90 of 0.9 s.
It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.
CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.
GCN Circular 22978
Subject
GRB 180715A: MASTER optical observation
Date
2018-07-20T18:09:52Z (7 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
D. Vlasenko, N.Tiurina, E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Kuznetsov,
V.Chazov, I. Gorbunov, D.Zimnukhov, D.Kuvshinov, P.Balanutsa, V.Vladimirov
Lomonosov Moscow State University,SAI
4
A. Tlatov, V.Senik, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory
R. Podesta, F. Podesta, C. Lopez, C.Francile
Observatorio Astronomico Felix Aguilar (OAFA)
H.Levato,
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
O. Gres, N.M.Budnev , Yu.Ishmuhametova
Irkutsk State University (ISU)
A. Gabovich, V. Yurkov, Yu. Sergienko
Blagoveschensk Educational State University (BSPU)
D. Buckley,
South African Astronomical Observatory (SAAO)
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias (IAC)
MASTER-Tavrida robotic telescope (MASTER-Net: http://observ.pereplet.ru,
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in
Russia (SAI Crimea astronomical station) was pointed to the GRB180715A
(Ukwatta et al., GCN Circ #22947) 96 sec after trigger time at 2018-07-15
18:08:41 UT as sun altitude was -6.95 dec first image was at 2018-07-15
18:30:37. On our first (180s exposure) set we do not found optical
transients within Swift error-box (ra=235.069 dec=-0.925 r=0.05) brighter
then 20.7.
The observations made on zenit distance = 44.16 degrees, galaxy latitude b
= 40,1 degree.
The moon (10 % bright part) is 8 degrees above the horizon. The distance
between moon and object is 82
The sun altitude is -9.85 degree.
The object can be observed till 2018-07-15 21:36:28
MASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru,
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in
South Africa (South African Astronomical observatory) was pointed to the
GRB180715A (Ukwatta et al., GCN Circ #22947) 495 sec after trigger time at
2018-07-15 18:15:20 UT . On our first (100s exposure) set we do not
found optical transients within Swift error-box (ra=235.069 dec=-0.925
r=0.05) brighter then 20.8.
The observations made on zenit distance = 57.43 degrees, galaxy latitude b
= 40.1 degree.
The moon (10 % bright part) is 6.5 degrees above the horizon. The distance
between moon and object is 83
The sun altitude is -28.83 degree.
The object can be observed till 2018-07-15 22:48:22.
The visibility GRB error box (coord: 235.069 -0.925 error_box: 0.05) at
trigger time at different MASTER sites:
obj: 44.19 sun: -6.73 - Tavrida (Crimea, Russia)
obj: 36.94 sun: 23.52 - IAC, Teide (Tenerife,Spain)
obj: 57.43 sun: -28.83 - SAAO (Sutherland, SA)
obj: 43.89 sun: -11.87 - Kislovodsk (Russia)
obj: 27.30 sun: -7.55 - Ural (Kourovka, Russia)
obj: 9.49 sun: -15.74 - Tunka (near Baykal Lake, Russia)
obj: -5.64 sun: -10.73 - Amur(Blagoveschensk)
obj: -7.22 sun: 32.97 - OAFA (Argentina)
The message may be cited.
GCN Circular 22968
Subject
GRB 180715A: Gemini imaging upper limits
Date
2018-07-19T22:55:09Z (7 years ago)
From
Wen-fai Fong at Northwestern U <wfong@northwestern.edu>
W. Fong (Northwestern Univ.), A. J. Levan (U. Warwick), R. Chornock (Ohio Univ.) report on behalf of a larger collaboration:
"We observed the location of the short-duration GRB 180715A (Ukwatta et al., GCN 22947) with the twin Gemini-North and Gemini-South 8-meter telescopes located on Mauna Kea, Hawaii and Cerro Pachon, Chile, respectively. We used the pair of Gemini Multi-Object Spectrographs (GMOS) to obtain r-band imaging at mid-times of 5.9 hr, 13.0 hr and 1.2 days post-burst, spanning 2018 Jul 16-Jul 17 UT. Our observational coverage of the refined Swift/BAT position (90% containment; Ukwatta et al., GCN 22951) as well as the uncatalogued Swift/XRT sources (Kennea et al., GCN 22953) is as follows:
5.9 hr: ~70% of BAT position, XRT S7 and S11
13.0 hr: 100% of BAT position, XRT S8
1.2 days: 100% of BAT position, XRT S8
We identify optical sources in and around each of these 3 XRT sources (90% containment; Kennea et al., GCN 22953) in our imaging; however, all sources are clearly visible in archival PS1 or SDSS imaging and have measured magnitudes within +/- 0.3 mag of known values. Furthermore, we do not detect any uncatalogued optical sources in or around these 3 XRT sources to 3-sigma limits of r>23.6 AB mag (S7 and S11 at 5.9 hr) and r>25.2 AB mag (S8 at 13.0 hr). The photometry is calibrated to SDSS DR12 and is not corrected for Galactic extinction in the direction of the burst.
Finally, we perform image subtraction between the observations at 13.0 hr and 1.2 days, which each provide full coverage of the refined BAT position (90% containment). We note that there is significant contamination from the 8th mag star that affects ~20% of the BAT position in the subtraction. For the remaining, uncontaminated region, we place a 3-sigma limit of r>24 AB mag on the optical afterglow of GRB 180715A at 13.0 hr after the burst.
We thank the Gemini-North and Gemini-South queue observers and staff for their rapid assistance with these observations."
GCN Circular 22967
Subject
GRB 180715A: Swift/UVOT Upper Limits
Date
2018-07-19T15:46:40Z (7 years ago)
From
Mike Siegel at PSU/Swift MOC <siegel@swift.psu.edu>
M. H. Siegel (PSU) and T. N. Ukwatta (LANL)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 180715A
4312 s after the BAT trigger (Ukwatta et al., GCN Circ. 22947).
No optical afterglow consistent with the BAT position (Ukwatta et al., GCN
Circ. 22951) 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 4312 4462 147 >20.6
white 4312 5695 344 >21.0
v 4469 4669 197 >19.1
b 5290 5490 197 >20.1
u 5085 5284 197 >19.8
w1 4879 5079 197 >19.5
m2 4674 4874 197 >19.7
w2 5701 5726 25 >18.7
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.13 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 22956
Subject
GRB 180715A: CALET Gamma-Ray Burst Monitor detection
Date
2018-07-18T06:03:29Z (7 years ago)
From
Takanori Sakamoto at AGU <tsakamoto@phys.aoyama.ac.jp>
S. Torii (Waseda U), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita, Y. Kawakubo,
A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU), S. Ricciarini (U of Florence),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:
The short, hard GRB 180715A (Swift-BAT trigger #848048:
Ukwatta, et al., GCN Circ. 22947, 22951; Fermi-GBM detection:
Hamburg and Meegan, GCN Circ. 22952) triggered the CALET Gamma-ray
Burst Monitor (CGBM) at 18:07:04.799 UTC on 15 July 2018.
The burst signal was seen by all CGBM detectors.
The burst light curve shows a double-peaked pulse which starts
at T+0.192 sec and ends at T+0.784 sec.
The T90 and the T50 durations measured by the SGM data are
0.53 +- 0.07 sec and 0.34 +- 0.12 sec (40-1000 keV), respectively.
The time-averaged spectrum of the burst (measured by the SGM from
T+0.192 sec to T+0.784 sec) is best fit in the 0.03-10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.64(-0.37, +0.46) and Ep = 707(-195, +337) keV (chi2 = 29.4/32 dof).
The resulting fluence in this energy range is 2.32(-0.50, +0.65)x10^-6 erg/cm2.
The quoted errors are at 90% CL.
The ground processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1215713118/
All the quoted values are preliminary.
The CALET data used in this analysis are provided by the Waseda CALET
Operation Center located at the Waseda University.
GCN Circular 22955
Subject
GRB 180715A: LCO Sutherland observations
Date
2018-07-17T09:43:53Z (7 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
C. Guidorzi, R. Martone (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell
(U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU), A. Cucchiara,
D. Morris (U. of Virgin Islands) on behalf of a large collaboration report:
With reference to the observation of our previous report (Guidorzi et
al. GCN 22949), within the XRT error circles of the five X-ray sources
(Kennea et al. GCN 22953) we found no uncatalogued source down to
r'>20.0 mag at a mid time of 0.28 hours after the GRB trigger time
(5x120s exposure), as calibrated against nearby SDSS objects.
GCN Circular 22954
Subject
GRB 180715A: COATLI Optical Observations
Date
2018-07-17T04:44:52Z (7 years ago)
From
Alan M. Watson at Instituto de Astronomia UNAM <alan@astro.unam.mx>
Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), William
H. Lee (UNAM), Carlos Rom��n-Z����iga (UNAM), Alexander Kutyrev (GSFC), and
Eleonora Troja (GSFC) report:
We observed the field of the short GRB 180715A (Ukwatta et al., GCN Circ.
22947) with the COATLI 50-cm telescope and interim imager at the
Observatorio Astron��mico Nacional on the Sierra de San Pedro M��rtir
(http://coatli.astroscu.unam.mx) from 2018-07-16 03:40:25 to 08:07:12 UTC
(9.55 to 14.00 hours after the trigger), obtaining a total of 3.33 hours
of exposure in the w filter.
We do not detect any optical sources coincident with the five X-ray
sources reported by Kennea et al. (GCN Circ. 22953) to a 5-sigma limiting
magnitude of
w > 22.4
This magnitude is calibrated against the USNO-B1 catalog (adjusted to an
approximate AB system) and is not corrected for Galactic extinction in
the direction of the GRB.
We thank the COATLI technical team (Fernando ��ngeles, Oscar Chapa,
Salvador Cuevas, Alejandro Farah, Jorge Fuentes, Rosal��a Langarica,
Fernando Quir��s, and Carlos Tejada) and the staff of the Observatorio
Astron��mico Nacional.
GCN Circular 22953
Subject
GRB 180715A: Swift-XRT observations
Date
2018-07-16T23:29:17Z (7 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), S.L. Gibson (U.
Leicester), Z. Liu (NAOC / U. Leicester), J.P. Osborne (U. Leicester),
A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB),
D.N. Burrows (PSU) and T. N. Ukwatta (LANL) report on behalf of the
Swift-XRT team:
We have analysed 14 ks of Photon Counting (PC) mode XRT data for the
Swift/BAT-detected burst GRB 180715A (Ukwatta et al. GCN Circ. 22951),
collected between T0+11.0 ks and T0+67.7 ks.
Five uncatalogued X-ray sources have been detected consistent with
being within 296 arcsec of the Swift/BAT position, however none of them
is above the RASS limit or shows definitive signs of fading. Therefore,
at the present time we cannot identify which, if any, is the afterglow.
The 3-sigma upper limit at the BAT position is 9.5x10^-4 ct/sec.
Details of these sources are given below:
Source 5:
RA (J2000.0): 235.1362 = 15:40:32.68
Dec (J2000.0): -0.9559 = -00:57:21.2
Error: 6.1 arcsec (radius, 90% conf.)
Count-rate: (5.4 [+2.7, -2.1])e-4 ct s^-1
Distance: 266 arcsec from Swift/BAT position.
Source 7:
RA (J2000.0): 235.0967 = 15:40:23.21
Dec (J2000.0): -0.9760 = -00:58:33.6
Error: 5.4 arcsec (radius, 90% conf.)
Count-rate: (7.4 [+3.2, -2.6])e-4 ct s^-1
Distance: 210 arcsec from Swift/BAT position.
Source 8:
RA (J2000.0): 235.1256 = 15:40:30.15
Dec (J2000.0): -0.8791 = -00:52:44.8
Error: 6.5 arcsec (radius, 90% conf.)
Count-rate: (8.2 [+3.3, -2.7])e-4 ct s^-1
Distance: 261 arcsec from Swift/BAT position.
Flux: (5.6 [+2.3, -1.8])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)
Source 10:
RA (J2000.0): 234.9980 = 15:39:59.51
Dec (J2000.0): -0.9504 = -00:57:01.5
Error: 5.0 arcsec (radius, 90% conf.)
Count-rate: (1.85 [+0.46, -0.42])e-3 ct s^-1
Distance: 272 arcsec from Swift/BAT position.
Flux: (8.9 [+2.2, -2.0])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)
Source 11:
RA (J2000.0): 235.0291 = 15:40:6.98
Dec (J2000.0): -0.9196 = -00:55:10.6
Error: 10.7 arcsec (radius, 90% conf.)
Count-rate: (4.4 [+2.5, -2.0])e-4 ct s^-1
Distance: 144 arcsec from Swift/BAT position.
Ten uncatalogued sources were also detected too far from the GRB
position to be likely afterglow candidates.
The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
http://www.swift.ac.uk/ToO_GRBs/00848048.
This circular is an official product of the Swift-XRT team.
GCN Circular 22952
Subject
GRB 180715A: Fermi GBM detection
Date
2018-07-16T04:35:23Z (7 years ago)
From
Rachel Hamburg at UAH <rkh0007@uah.edu>
R. Hamburg (UAH) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:
"At 18:07:05.06 UT on 15 July 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 180715A (trigger 553370830 / 180715755)
which was also detected by the Swift/BAT (Ukwatta et al. 2018, GCN 22947).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 75
degrees.
The GBM light curve shows a single structured peak
with a duration (T90) of about 0.7 s (50-300 keV).
The time-averaged spectrum from T0-0.19 to T+0.51 s is
adequately fit by a power law function with an exponential
high-energy cutoff. The power law index is -0.14 +/- 0.21 and
the cutoff energy, parameterized as Epeak, is 852 +/- 182 keV.
The event fluence (10-1000 keV) in this time interval is
(1.7 +/- 0.1)E-06 erg/cm^2. The 64-ms peak photon flux measured
starting from T0-0.064s in the 10-1000 keV band
is 8.4 +/- 1.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
GCN Circular 22951
Subject
GRB 180715A: Swift-BAT refined analysis
Date
2018-07-16T00:39:59Z (7 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU) (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 180715A (trigger #848048)
(Ukwatta et al., GCN Circ. 22947). The BAT ground-calculated position is
RA, Dec = 235.085, -0.899 deg which is
RA(J2000) = 15h 40m 20.5s
Dec(J2000) = -00d 53' 57.6"
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 85%.
The mask-weighted light curve shows a double-peaked structure that starts
at ~T-0.1 and ends at ~T+0.6, The two peaks occur at ~T+0.1 and ~T+0.5,
respectively. T90 (15-350 keV) is 0.68 +- 0.09 sec (estimated error including
systematics).
The time-averaged spectrum from T-0.14 to T+0.63 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
0.74 +- 0.27. The fluence in the 15-150 keV band is 1.3 +- 0.2 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.26 sec in the 15-150 keV band
is 1.2 +- 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/848048/BA/
GCN Circular 22950
Subject
GRB 180715A: GOTO optical limits
Date
2018-07-15T23:27:04Z (7 years ago)
From
Joe Lyman at U of Warwick <j.d.lyman@warwick.ac.uk>
J.Lyman, D.Steeghs (U. Warwick), G.Ramsay (Armagh O.), M.Dyer
(U. Sheffield), K.Ulaczyk, B.Gompertz, A.Levan, R.Cutter (U. Warwick)
K. Ackley, D.Galloway, E.Rol (Monash U.), V.Dhillon (U. Sheffield),
P.O'Brien, N.Tanvir (U. Leicester), S.Poshyachinda (NARIT),
D.Pollacco (U. Warwick), E.Thrane (Monash U.)
report on behalf of the GOTO collaboration:
In response to GRB 180715A (Ukwatta et al. GCN 22947), the
Gravitational-wave Optical Transient Observer (GOTO) observed the
field near the Swift BAT detection.
Observations started at 2018-07-15T22:37:10 UT (4.5 hours after the
burst) consisted of a set of 3x120s exposures in our wide L filter
(400-700nm). We detect the source identified by Guidorzi et al.
(GCN 22949) but note that this source appears in PanSTARRS
images of the field and in the Gaia catalogue and is thus likely to
be unrelated. We did not detect any other uncatalogued source within
the BAT localisation uncertainty. A preliminary analysis of the stacked
image was used to derive a 5-sigma upper limit of V>20.5 mag.
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 22949
Subject
GRB 180715A: LCO Sutherland possible optical candidate
Date
2018-07-15T19:58:20Z (7 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
C. Guidorzi, R. Martone (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell
(U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU), A. Cucchiara,
D. Morris (U. of Virgin Islands) on behalf of a large collaboration report:
One of the LCO 1-m units at Sutherland Observatory (South Africa)
automatically began observing Swift GRB 180715A (Ukwatta et al. GCN
22947) on July 15, 18:17:37 UT (10.5 minutes after the GRB trigger time)
with the SDSS r' filter. Within the Swift-BAT error circle, well within
the glare of a 8-mag catalogued object we clearly detect a source which
is not present in the SDSS catalogue at the following position:
RA(J2000)=�� 15:40:22.30
DEC(J2000)= -00:54:44.4
with an error radius of ~1".
GCN Circular 22948
Subject
GRB 180715A: Swift-XRT observations
Date
2018-07-15T19:54:22Z (7 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
S. Campana (INAF-OAB), G. Cusumano (INAF-IASF PA), P.A. Evans (U.
Leicester), J.P. Osborne (U. Leicester), D.N. Burrows (PSU) and J.A.
Kennea (PSU) report on behalf of the Swift-XRT team:
The XRT began observing the field of GRB 180715A at 18:59:52.8 UT,
3167.8 seconds after the BAT trigger. No source was detected in 1.1 ks
of promptly downlinked data, which covered 73% of the BAT error circle.
We are waiting for the full dataset to detect and localise the XRT
counterpart.
GCN Circular 22947
Subject
GRB 180715A: Swift detection of a short hard burst
Date
2018-07-15T18:15:11Z (7 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC),
S. W. K Emery (UCL-MSSL), J.D. Gropp (PSU), S. J. LaPorte (PSU),
A. Y. Lien (GSFC/UMBC), Z. Liu (NAOC/U. Leicester),
D. M. Palmer (LANL) and A. Tohuvavohu (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:
At 18:07:05 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 180715A (trigger=848048). Swift could not immediately
slew to the location due to the Earth limb constraint.
The BAT on-board calculated location is
RA, Dec 235.069, -0.925 which is
RA(J2000) = 15h 40m 17s
Dec(J2000) = -00d 55' 28"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a single short
peak structure with a duration of about 0.7 sec. The peak count rate
was ~6000 counts/sec (15-350 keV), at ~0 sec after the trigger.
Due to an observing constraint, Swift will not slew until T0+50.9
minutes. There will be no XRT or UVOT data until this time.
Burst Advocate for this burst is T. N. Ukwatta (tilan.ukwatta 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.)