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GRB 181003A

GCN Circular 23295

Subject
GRB 181003A: Swift detection of a burst
Date
2018-10-03T05:25:47Z (7 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
A. P. Beardmore (U Leicester),
M. J. Moss (George Washington University), K. L. Page (U Leicester)
and D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 05:11:03 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 181003A (trigger=865179).  Swift did not slew immediately
to the burst due to an observing constraint. 
The BAT on-board calculated location is 
RA, Dec 52.569, -34.023 which is 
   RA(J2000) = 03h 30m 17s
   Dec(J2000) = -34d 01' 23"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single-peaked
structure with a duration of about 30 sec.  The peak count rate
was ~600 counts/sec (15-350 keV), at ~0 sec after the trigger. 

Due to an observing constraint, Swift will not slew until T0+46.3
minutes. There will be no XRT or UVOT data until this time. 

Burst Advocate for this burst is A. P. Beardmore (apb AT star.le.ac.uk). 
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 23296

Subject
GRB 181003A: Swift-XRT observations
Date
2018-10-03T06:56:48Z (7 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), D.N. Burrows
(PSU), J.A. Kennea (PSU), M. Perri (ASDC) and G. Tagliaferri (INAF-OAB)
report on behalf of the Swift-XRT team:

The XRT began observing the field of GRB 181003A at 06:02:32.6 UT,
3089.4 seconds after the BAT trigger. Using promptly downlinked data we
find an uncatalogued X-ray source located at RA, Dec 52.52910,
-33.96445 which is equivalent to:
   RA(J2000)  = 03h 30m 06.98s
   Dec(J2000) = -33d 57' 52.0"
with an uncertainty of 4.5 arcseconds (radius, 90% containment). This
location is 242 arcseconds from the BAT onboard position. 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. As this position is
significantly outside the BAT error circle, it is probably unrelated to
the trigger. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 1.24
x 10^20 cm^-2 (Willingale et al. 2013).

GCN Circular 23299

Subject
GRB 181003A: MASTER optical observation
Date
2018-10-03T13:57:37Z (7 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, N.Tyurina, P.Balanutsa,A.Kuznetsov, V.V.Chazov, D. Vlasenko
Lomonosov Moscow State University, Sternberg Astronomical Institute

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias

Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias

D. Buckley,
South African Astronomical Observatory

A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory

O. Gres, N.M. Budnev, Yu.Ishmuhametova
Applied Physics Institute of Irkutsk State University

V. Yurkov, A. Gabovich, Yu. Sergienko
Blagoveschensk Educational State University, Blagoveschensk

MASTER-IAC robotic telescope  (MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)
located in Spain (IAC Teide Observatory) was pointed to Swift GRB181003A (Beardmore et al. GCN 23295, Evans et al. GCN 23296)
  4 sec after notice time and 59 sec after trigger time at 2018-10-03 05:12:02 UT, with 
upper limit up to  19.1 mag.
The observations started on zenit distance = 65 deg.
The sun  altitude  was -23.8 deg.

MASTER-OAFA robotic telescope  located in Argentina (OAFA observatory of San Juan National University)
was pointed to the  GRB181003A
10 sec after notice time and 64 sec after trigger time at 2018-10-03 05:12:08 UT, 
with upper limit up to  20.3 mag.
The observations started on zenit distance = 27 deg.
The sun  altitude  was -53.3 deg.

The galactic latitude b = -60 deg., longitude l = 98 deg.

We obtained the following upper limits:

Tmid-T0  |  MASTER observatory |Filt.| Exp.,s| m_lim | Comment
_________|_____________________|_____|_______|_______|________

       89 |          MASTER-IAC |  P- |    10 | 16.29 |
       89 |          MASTER-IAC |  P- |    50 | 17.38 |  Coadd
       89 |          MASTER-IAC |  P- |   710 | 19.12 |  Coadd
       96 |         MASTER-OAFA |   C |    10 | 16.88 |
       96 |         MASTER-OAFA |   C |    70 | 18.69 |  Coadd
       96 |         MASTER-OAFA |   C |   550 | 19.83 |  Coadd
      131 |          MASTER-IAC |  P- |    20 | 16.75 |
      176 |         MASTER-OAFA |   C |    20 | 17.54 |
      185 |          MASTER-IAC |  P- |    20 | 16.75 |
      242 |          MASTER-IAC |  P- |    30 | 17.31 |
      242 |          MASTER-IAC |  P- |   120 | 17.94 |  Coadd
      272 |         MASTER-OAFA |   C |    40 | 18.17 |
      312 |          MASTER-IAC |  P- |    40 | 17.05 |
      393 |         MASTER-OAFA |   C |    50 |  18.4 |
      393 |         MASTER-OAFA |   C |   210 |  19.3 |  Coadd
      399 |          MASTER-IAC |  P- |    50 | 17.53 |
      500 |          MASTER-IAC |  P- |    70 | 17.66 |
      500 |          MASTER-IAC |  P- |   250 | 18.41 |  Coadd
      531 |         MASTER-OAFA |   C |    70 |  18.7 |
      632 |          MASTER-IAC |  P- |    80 | 17.66 |
      701 |         MASTER-OAFA |   C |    90 | 18.81 |
      774 |          MASTER-IAC |  P- |   100 | 17.92 |
      900 |         MASTER-OAFA |   C |   120 | 19.05 |
      900 |         MASTER-OAFA |   C |   450 | 19.72 |  Coadd
      951 |          MASTER-IAC |  P- |   130 | 17.92 |
     1145 |         MASTER-OAFA |   C |   150 | 19.18 |
     1170 |          MASTER-IAC |  P- |   160 | 17.92 |
     1434 |         MASTER-OAFA |   C |   180 | 19.31 |
     1434 |         MASTER-OAFA |   C |  1800 | 20.16 |  Coadd
     1436 |          MASTER-IAC |  P- |   180 | 18.15 |
     1436 |          MASTER-IAC |  P- |  1800 | 19.11 |  Coadd
     1749 |          MASTER-IAC |  P- |   180 | 18.16 |
     1749 |          MASTER-IAC |  P- |   540 |    19 |  Coadd
     1764 |         MASTER-OAFA |   C |   180 | 19.26 |
     1764 |         MASTER-OAFA |   C |   540 | 19.84 |  Coadd
     2070 |          MASTER-IAC |  P- |   180 | 18.16 |
     2097 |         MASTER-OAFA |   C |   180 | 19.27 |
     2382 |          MASTER-IAC |  P- |   180 | 18.16 |
     2429 |         MASTER-OAFA |   C |   180 |  19.3 |
     2709 |          MASTER-IAC |  P- |   180 | 18.14 |
     2709 |          MASTER-IAC |  P- |   540 | 18.97 |  Coadd
     2760 |         MASTER-OAFA |   C |   180 | 19.26 |
     2760 |         MASTER-OAFA |   C |   540 | 19.81 |  Coadd
     3027 |          MASTER-IAC |  P- |   180 | 18.14 |
     3093 |         MASTER-OAFA |   C |   180 | 19.26 |
     3428 |         MASTER-OAFA |   C |   180 | 19.25 |
     3761 |         MASTER-OAFA |   C |   180 |  19.3 |
     3761 |         MASTER-OAFA |   C |   540 |  19.9 |  Coadd
     3887 |          MASTER-IAC |  P- |   180 | 17.93 |
     4094 |         MASTER-OAFA |   C |   180 | 19.27 |
     4203 |          MASTER-IAC |  P- |   180 | 17.89 |
     4203 |          MASTER-IAC |  P- |   540 | 18.43 |  Coadd
     4428 |         MASTER-OAFA |   C |   180 |  19.3 |
     4515 |          MASTER-IAC |  P- |   180 | 17.73 |
     4758 |         MASTER-OAFA |   C |   180 |  19.3 |
     4758 |         MASTER-OAFA |   C |   540 | 19.85 |  Coadd
     4758 |         MASTER-OAFA |   C |  1800 | 20.26 |  Coadd
     4835 |          MASTER-IAC |  P- |   180 | 17.45 |
     5093 |         MASTER-OAFA |   C |   180 |  19.3 |
     5151 |          MASTER-IAC |  P- |   180 | 17.08 |
     5151 |          MASTER-IAC |  P- |   540 | 17.39 |  Coadd
Filter C is unfiltred band (clear), calibrated by USNO B1 thousands field 
stars as 0.2B+0.8R.

The observation and reduction will continue.
The message may be cited.

GCN Circular 23300

Subject
GRB 181003A: LCO Cerro Tololo observations
Date
2018-10-03T14:56:21Z (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:

We automatically observed Swift GRB 181003A (Beardmore et al. GCN 23295) 
with one LCO 1-m unit at Cerro Tololo from October 03, 05:26:07 UT 
(corresponding to 15 minutes from the GRB trigger time) with the SDSS r' 
filter. Within the Swift-XRT error circle (Evans et al. GCN 23296) we 
marginally detect an uncatalogued source with r'=22.11 +- 0.25 mag from 
a 9x60s exposure at a mid time of 0.35 hours post GRB, as calibrated 
against nearby Pan-STARRS objects, at the following position:

RA(J2000) =� 03:30:06.86
DEC(J2000)= -33:57:54.2

with an error radius of about 1".

GCN Circular 23303

Subject
GRB 181003A: Swift/UVOT Upper Limits
Date
2018-10-03T17:47:56Z (7 years ago)
From
Sam LaPorte at PSU <sjl5346@psu.edu>
GRB 181003A: Swift/UVOT Upper Limits

S. J. LaPorte (PSU) and A. P. Beardmore (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 181003A
3095 s after the BAT trigger (Beardmore et al., GCN Circ. 23295).
No optical afterglow consistent with the XRT position
(Evans et al. GCN Circ. 23296)
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 initial exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

b              5040         5240           196            >20.83  
uvm2           3452         3652           196            >19.46 
u              3862         3902            39            >19.19 
v              3427         3447           196            >19.79 
uvw1           3658         3857           196            >19.85
uvw2           5451         5597           144            >19.37 
white          3091         3240           294            >21.73  

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 23305

Subject
GRB 181003A: Swift-XRT afterglow detection
Date
2018-10-03T18:08:13Z (7 years ago)
From
Andy Beardmore at U Leicester <ab271@leicester.ac.uk>
A. Tohuvavohu (PSU), A.P. Beardmore (U. Leicester), J.P. Osborne (U.
Leicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo
(INAF-OAB), S. J. LaPorte (PSU), J.A. Kennea (PSU) and P.A. Evans (U.
Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has performed follow-up observations of the
Swift/BAT-detected burst GRB 181003A (Beardmore et al. GCN Circ.
23295), collecting 8.6 ks of Photon Counting (PC) mode data between
T0+3.1 ks and T0+34.3 ks. 

Six uncatalogued X-ray sources are detected consistent with being
within 296 arcsec of the Swift/BAT position, of which one ("Source 1")
is fading with 3-sigma significance, and is therefore likely the GRB
afterglow. Using 1905 s of PC mode data and 1 UVOT image, we find an
enhanced XRT position (using the XRT-UVOT alignment and matching UVOT
field sources to the USNO-B1 catalogue): RA, Dec = 52.52869, -33.96466
which is equivalent to:

RA (J2000): 03h 30m 06.89s
Dec(J2000): -33d 57' 52.8"

with an uncertainty of 6.3 arcsec (radius, 90% confidence). This
position is 4.0 arcmin from the Swift/BAT position.  The source is
fading with alpha >0.8.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00865179.
The results of the full analysis of the XRT observations are available
at http://www.swift.ac.uk/ToO_GRBs/00865179.

This circular is an official product of the Swift-XRT team.

GCN Circular 23306

Subject
GRB 181003A: Swift-BAT refined analysis
Date
2018-10-03T22:34:55Z (7 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
H. A. Krimm (NSF/USRA), S. D. Barthelmy (GSFC),
A. P. Beardmore, J. R. Cummings (CPI),
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 181003A (trigger #865179)
(Beardmore et al., GCN Circ. 23295).  The BAT ground-calculated position is
RA, Dec = 52.481, -33.991 deg which is
  RA(J2000)  =  03h 29m 55.4s
  Dec(J2000) = -33d 59' 25.8"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 96%.

The mask-weighted light curve shows a weak structure that starts at ~T-10 s
and ends at ~ T+20 s. The burst went out of the BAT field of view at ~T+97 s.
T90 (15-350 keV) is 21.5 +- 4.8 sec (estimated error including systematics).

The time-averaged spectrum from T-11.20 to T+18.01 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index -0.20 +- 1.12,
and Epeak of 56.5 +- 14.4 keV (chi squared 52.40 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 4.2 +- 0.7 x 10^-7 erg/cm2
and the 1-sec peak flux measured from T+1.86 sec in the 15-150 keV band is
0.6 +- 0.1 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.54 +- 0.19 (chi squared 63.13 for 57 d.o.f.).  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/865179/BA/

GCN Circular 23307

Subject
GRB 181003A: RATIR Optical and NIR Observations
Date
2018-10-04T19:27:17Z (7 years ago)
From
Alan M. Watson at Instituto de Astronomia UNAM <alan@astro.unam.mx>
Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC),
William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J.
Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI),
Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz
(UCSC), Jes��s Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM), Harvey
Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki
Toy (UMD) report:

We observed the field of GRB 181003A (Beardmore et al., GCN Circ. 23295)
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 2018/10 4.32 to
2018/10 4.46 UTC (26.59 to 29.89 hours after the BAT trigger), obtaining
a total of 1.41 hours exposure in the r and i bands and 0.58 hours
exposure in the Z, Y, J, and H bands.

For a source within the Swift-XRT error circle (Tohuvavohu et al., GCN
Circ. 23305), in comparison with the USNO-B1 and 2MASS catalogs, we
obtain the following 3-sigma upper limits:

  r	> 23.40
  i	> 23.15
  Z	> 22.01
  Y	> 21.53
  J	> 21.19
  H	> 20.73

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.

We thank the staff of the Observatorio Astron��mico Nacional in San Pedro
M��rtir.

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