| Summary table |
|---|
| Variable |
Value |
Source |
| T0 |
2:04:02 UTC |
GCN_circulars,Swift Det |
| ra |
248.3290° |
Swift |
| decl |
19.5705° |
Swift |
| pos_error |
1.81e-04° |
Swift |
| T90 |
58.0 s |
Swift |
| T90_start |
2:04:02 UTC |
Swift |
| fluence |
1.30e-06 erg/cm² |
Swift |
| T100 |
58.0 s |
|
| GBM_located |
False |
|
| mjd |
58414.08613425926 |
GCN_circulars,Swift Det |
| IPN table |
|---|
| GRB_name |
GRB181023A |
| ra |
248.3292° |
| decl |
19.5667° |
| pos_error |
5.00e-02° |
| Swift table |
|---|
| GRB_name |
GRB181023A |
| t_trigger |
2:04:02 UTC |
| ra |
248.3290° |
| decl |
19.5705° |
| pos_error |
1.81e-04° |
| T90 |
58.0 s |
| fluence |
1.30e-06 erg/cm² |
| GCN 23366 table |
|---|
| GRB_name |
GRB181023A |
| GCN_number |
23366 |
| Detection_method |
Swift Det |
| t_trigger |
2:04:02 UTC |
| ra |
248.3290° |
| decl |
19.5640° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 23366
SUBJECT: GRB 181023A: Swift detection of a burst
DATE: 18/10/23 02:21:45 GMT
FROM: Jamie A. Kennea at PSU/Swift-XRT
F. E. Marshall (NASA/GSFC), A. D'Ai (INAF-IASFPA), V. D'Elia (SSDC),
J. A. Kennea (PSU), S. J. LaPorte (PSU), A. Y. Lien (GSFC/UMBC),
M. J. Moss (George Washington University) and D. M. Palmer (LANL)
report on behalf of the Neil Gehrels Swift Observatory Team:
At 02:04:02 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 181023A (trigger=868427). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 248.329, +19.564 which is
RA(J2000) = 16h 33m 19s
Dec(J2000) = +19d 33' 51"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). As is usual with an image trigger, the available
BAT light curve shows no significant structure.
The XRT began observing the field at 02:07:17.8 UT, 195.7 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 248.32979, 19.57140 which is equivalent
to:
RA(J2000) = 16h 33m 19.15s
Dec(J2000) = +19d 34' 17.0"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 26 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.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (6.04 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 3.4
(+2.82/-2.40) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 199 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
0.05.
Burst Advocate for this burst is F. E. Marshall (marshall AT milkyway.gsfc.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.)
|
| GCN 23368 table |
|---|
| GRB_name |
GRB181023A |
| GCN_number |
23368 |
| Detection_method |
Optical |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 23368
SUBJECT: GRB 181023A: KAIT Optical Upper Limit
DATE: 18/10/23 04:24:34 GMT
FROM: Weikang Zheng at UC Berkeley
Xuhui Han (NAOC), WeiKang Zheng (UC Berkeley) and Alexei V. Filippenko
(UC Berkeley) report on behalf of the KAIT GRB team:
The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory, responded to Swift GRB 181023A (Marshall et al.,
GCN 23366) starting at 02:16:07 UT, ~12 minutes after the burst
under dusk twilight condition. Observations were performed in the
clear (roughly R) filters, and the exposure time was 60s per image.
Observations lasted for about 25 minutes before it set beyond KAIT
hour agnle limit. We do not detect any optical afterglow candidate
within the XRT position error circle (Marshall et al., GCN 23366)
neither in single image, nor in the co-add images. The typical
limiting magnitude of our single clear image is about 19.0 mag
calibrated to the Pan-STARRS1 catalog.
|
| GCN 23369 table |
|---|
| GRB_name |
GRB181023A |
| GCN_number |
23369 |
| Detection_method |
Swift-XRT Det |
| ra |
248.3287° |
| decl |
19.5706° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 23369
SUBJECT: GRB 181023A: Enhanced Swift-XRT position
DATE: 18/10/23 04:59:08 GMT
FROM: Phil Evans at U of Leicester
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1424 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 181023A, 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 = 248.32870, +19.57062 which is equivalent
to:
RA (J2000): 16h 33m 18.89s
Dec (J2000): +19d 34' 14.2"
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 23373 table |
|---|
| GRB_name |
GRB181023A |
| GCN_number |
23373 |
| Detection_method |
Swift-XRT Other |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 23373
SUBJECT: GRB 181023A: Swift-XRT refined Analysis
DATE: 18/10/23 15:40:45 GMT
FROM: Phil Evans at U of Leicester
A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB),
D.N. Burrows (PSU), A. Tohuvavohu (PSU), S. J. LaPorte (PSU), A.P.
Beardmore (U. Leicester), P.A. Evans (U. Leicester), J.P. Osborne (U.
Leicester) and F.E. Marshall report on behalf of the Swift-XRT team:
We have analysed 10 ks of XRT data for GRB 181023A (Marshall et al. GCN
Circ. 23366), from 214 s to 36.1 ks after the BAT trigger. The data
comprise 493 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Osborne et al. (GCN Circ. 23369).
The late-time light curve (from T0+5.4 ks) can be modelled with a
series of power-law decays. The initial decay index is alpha=1.56
(+0.16, -0.18). At T+12.4 ks the decay steepens to an alpha of 3.9
(+2.1, -0.4). The light curve breaks again at T+18.1 ks to a decay with
alpha=-1.5 (+0.0, -0.7), before a final break at T+22.9 ks s after
which the decay index is 2.9 (+0.9, -0.7).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.79 (+/-0.08). The
best-fitting absorption column is 2.3 (+/-0.3) x 10^21 cm^-2, in
excess of the Galactic value of 6.0 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 4.1 x 10^-11 (5.2 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 2.3 (+/-0.3) x 10^21 cm^-2
Galactic foreground: 6.0 x 10^20 cm^-2
Excess significance: 9.0 sigma
Photon index: 1.79 (+/-0.08)
If the light curve continues to decay with a power-law decay index of
2.9, the count rate at T+24 hours will be 4.5 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.8 x
10^-13 (2.4 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/00868427.
This circular is an official product of the Swift-XRT team.
|
| GCN 23376 table |
|---|
| GRB_name |
GRB181023A |
| GCN_number |
23376 |
| Detection_method |
Swift-UVOT Other |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 23376
SUBJECT: GRB 181023A: Swift/UVOT Upper Limits
DATE: 18/10/24 00:52:14 GMT
FROM: Sam LaPorte at PSU
GRB 181023A: Swift/UVOT Upper Limits
S. J. LaPorte (PSU) and F. E. Marshall (NASA/GSFC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 181023A
200 s after the BAT trigger (Marshall et al., GCN Circ. 23366).
No optical afterglow consistent with the XRT position
(Osborne et al. GCN Circ. 23369)
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 200 350 147 >20.1
white 200 2078 470 >20.8
v 356 2128 194 >19.4
b 455 2054 175 >20.3
u 430 2029 175 >19.6
w1 406 2005 175 >19.6
m2 554 1803 78 >19.2
w2 679 2104 175 >19.2
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.05 in the direction of the burst
(Schlegel et al. 1998).
|
| GCN 23377 table |
|---|
| GRB_name |
GRB181023A |
| GCN_number |
23377 |
| Detection_method |
Swift-BAT Det |
| ra |
248.3220° |
| decl |
19.5810° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 23377
SUBJECT: GRB 181023A: Swift-BAT refined analysis
DATE: 18/10/24 01:39:15 GMT
FROM: Amy Lien at GSFC
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),
F. E. Marshall (NASA/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 181023A (trigger #868427)
(Marshall et al., GCN Circ. 23366). The BAT ground-calculated position is
RA, Dec = 248.322, 19.581 deg which is
RA(J2000) = 16h 33m 17.4s
Dec(J2000) = +19d 34' 51.2"
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 53%.
The mask-weighted light curve shows a complex structure with some
weak overlapping pulses that starts at ~T-30 s and ends at ~T+40 s.
Note that the burst entered the BAT FOV at T-48 s, and hence there might
be additional emission beforehand. T90 (15-350 keV) is 58.0 +- 8.8 sec (estimated
error including systematics).
The time-averaged spectrum from T-27.62 to T+36.68 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.74 +- 0.24. The fluence in the 15-150 keV band is 1.3 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+32.18 sec in the 15-150 keV band
is 1.0 +- 0.3 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/868427/BA/
|