| Summary table |
|---|
| Variable |
Value |
Source |
| T0 |
9:04:49 UTC |
GCN_circulars,Swift Det |
| ra |
167.5657° |
Swift |
| decl |
-45.3324° |
Swift |
| pos_error |
2.59e-04° |
Swift |
| T90 |
1.68 s |
Swift |
| T90_start |
9:04:49 UTC |
Swift |
| fluence |
1.10e-07 erg/cm² |
Swift |
| T100 |
1.68 s |
|
| GBM_located |
False |
|
| mjd |
58335.37834490741 |
GCN_circulars,Swift Det |
| IPN table |
|---|
| GRB_name |
GRB180805A |
| ra |
167.5292° |
| decl |
-45.3333° |
| pos_error |
5.00e-02° |
| Swift table |
|---|
| GRB_name |
GRB180805A |
| t_trigger |
9:04:49 UTC |
| ra |
167.5657° |
| decl |
-45.3324° |
| pos_error |
2.59e-04° |
| T90 |
1.68 s |
| fluence |
1.10e-07 erg/cm² |
| GCN 23074 table |
|---|
| GRB_name |
GRB180805A |
| GCN_number |
23074 |
| Detection_method |
Swift Det |
| t_trigger |
9:04:49 UTC |
| ra |
167.5300° |
| decl |
-45.3310° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 23074
SUBJECT: GRB 180805A: Swift detection of a burst
DATE: 18/08/05 09:23:39 GMT
FROM: Scott Barthelmy at NASA/GSFC
P. D'Avanzo (INAF-OAB), S. D. Barthelmy (GSFC),
S. W. K Emery (UCL-MSSL), N. P. M. Kuin (UCL-MSSL),
A. Y. Lien (GSFC/UMBC), A. Melandri (INAF-OAB),
M. J. Moss (George Washington University) and B. Sbarufatti (PSU)
report on behalf of the Neil Gehrels Swift Observatory Team:
At 09:04:49 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 180805A (trigger=851829). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 167.530, -45.331 which is
RA(J2000) = 11h 10m 07s
Dec(J2000) = -45d 19' 50"
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 1.5 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 09:06:15.1 UT, 86.1 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 167.5646, -45.3307
which is equivalent to:
RA(J2000) = 11h 10m 15.50s
Dec(J2000) = -45d 19' 50.5"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 87 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 1.68
x 10^21 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 89 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 0.19.
Burst Advocate for this burst is P. D'Avanzo (paolo.davanzo AT brera.inaf.it).
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 23075 table |
|---|
| GRB_name |
GRB180805A |
| GCN_number |
23075 |
| Detection_method |
Swift-XRT Det |
| ra |
167.5663° |
| decl |
-45.3322° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 23075
SUBJECT: GRB 180805A: Enhanced Swift-XRT position
DATE: 18/08/05 12:09:32 GMT
FROM: Phil Evans at U of Leicester
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1075 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 180805A, 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 = 167.56626, -45.33222 which is equivalent
to:
RA (J2000): 11h 10m 15.90s
Dec (J2000): -45d 19' 56.0"
with an uncertainty of 2.5 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 23081 table |
|---|
| GRB_name |
GRB180805A |
| GCN_number |
23081 |
| Detection_method |
Swift-BAT Det |
| ra |
167.5750° |
| decl |
-45.3270° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 23081
SUBJECT: GRB 180805A: Swift-BAT refined analysis
DATE: 18/08/06 01:48:56 GMT
FROM: Amy Lien at GSFC
D. M. Palmer (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), P. D'Avanzo (INAF-OAB),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), J. P. Norris (BSU),
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 180805A (trigger #851829)
(D'Avanzo et al., GCN Circ. 23074). The BAT ground-calculated position is
RA, Dec = 167.575, -45.327 deg which is
RA(J2000) = 11h 10m 18.1s
Dec(J2000) = -45d 19' 35.8"
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 64%.
The mask-weighted light curve shows a single-pulse structure that starts
at peaks at ~T0, and ends at ~T+1.9 s. T90 (15-350 keV) is 1.68 +- 0.41 sec
(estimated error including systematics).
The time-averaged spectrum from T+0.04 to T+1.90 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.58 +- 0.32. The fluence in the 15-150 keV band is 1.1 +- 0.3 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.13 sec in the 15-150 keV band
is 1.1 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
Both the temporal and spectral properties of this burst lie in the
intermediate region between short and long GRBs. The lag analysis
is unavailable due to the weakness of this burst. No extended emission
is found.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/851829/BA/
|
| GCN 23084 table |
|---|
| GRB_name |
GRB180805A |
| GCN_number |
23084 |
| Detection_method |
Swift-XRT Other |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 23084
SUBJECT: GRB 180805A: Swift-XRT refined Analysis
DATE: 18/08/06 09:25:04 GMT
FROM: Phil Evans at U of Leicester
J.A. Kennea (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U.
Leicester), S.L. Gibson (U. Leicester), V. D'Elia (ASDC), A. D'Ai
(INAF-IASFPA), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU) and P.
D'Avanzo report on behalf of the Swift-XRT team:
We have analysed 4.4 ks of XRT data for GRB 180805A (D'Avanzo et al.
GCN Circ. 23074), from 93 s to 12.5 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. 23075).
The light curve can be modelled with a power-law decay with a decay
index of alpha=0.32 (+/-0.14).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.50 (+0.54, -0.25). The
best-fitting absorption column is consistent with the Galactic value
of 1.7 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum is 4.5 x 10^-11 (5.0 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.7 (+/-2.2) x 10^21 cm^-2
Galactic foreground: 1.7 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.50 (+0.54, -0.25)
If the light curve continues to decay with a power-law decay index of
0.32, the count rate at T+24 hours will be 5.9 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.7 x
10^-13 (3.0 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/00851829.
This circular is an official product of the Swift-XRT team.
|