| Summary table |
|---|
| Variable |
Value |
Source |
| T0 |
9:27:32 UTC |
GCN_circulars,Swift Det |
| ra |
98.1344° |
Swift |
| decl |
-58.6914° |
Swift |
| pos_error |
2.33e-04° |
Swift |
| T90 |
2.32 s |
Swift |
| T90_start |
9:27:32 UTC |
Swift |
| fluence |
2.40e-07 erg/cm² |
Swift |
| T100 |
2.32 s |
|
| GBM_located |
False |
|
| mjd |
58098.39412037037 |
GCN_circulars,Swift Det |
| IPN table |
|---|
| GRB_name |
GRB171211A |
| ra |
98.1083° |
| decl |
-58.6667° |
| pos_error |
5.00e-02° |
| Swift table |
|---|
| GRB_name |
GRB171211A |
| t_trigger |
9:27:32 UTC |
| ra |
98.1344° |
| decl |
-58.6914° |
| pos_error |
2.33e-04° |
| T90 |
2.32 s |
| fluence |
2.40e-07 erg/cm² |
| GCN 22234 table |
|---|
| GRB_name |
GRB171211A |
| GCN_number |
22234 |
| Detection_method |
Swift Det |
| t_trigger |
9:27:32 UTC |
| ra |
98.1080° |
| decl |
-58.6700° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22234
SUBJECT: GRB 171211A: Swift detection of a possibly short burst
DATE: 17/12/11 09:47:21 GMT
FROM: Jamie A. Kennea at PSU/Swift-XRT
J.D. Gropp (PSU), A. P. Beardmore (U Leicester),
A. A. Breeveld (UCL-MSSL), P. D'Avanzo (INAF-OAB),
P. A. Evans (U Leicester), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC)
and K. L. Page (U Leicester) report on behalf of the Swift Team:
At 09:27:32 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 171211A (trigger=796469). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 98.108, -58.670 which is
RA(J2000) = 06h 32m 26s
Dec(J2000) = -58d 40' 10"
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 3 sec. The peak count rate
was ~2000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 09:29:04.7 UT, 91.9 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source located at RA, Dec 98.13327, -58.69205 which
is equivalent to:
RA(J2000) = 06h 32m 31.98s
Dec(J2000) = -58d 41' 31.4"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 92 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 consistent with the Galactic value of 8.89
x 10^20 cm^-2 (Willingale et al. 2013).
There is no UVOT data available because of a bright source in the field of view.
Burst Advocate for this burst is J.D. Gropp (jdg44 AT psu.edu).
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 22236 table |
|---|
| GRB_name |
GRB171211A |
| GCN_number |
22236 |
| Detection_method |
Swift-XRT Det |
| ra |
98.1354° |
| decl |
-58.6921° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22236
SUBJECT: GRB 171211A: Enhanced Swift-XRT position
DATE: 17/12/11 13:39:36 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 1720 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 171211A, 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 = 98.13542, -58.69209 which is equivalent
to:
RA (J2000): 06h 32m 32.50s
Dec (J2000): -58d 41' 31.5"
with an uncertainty of 2.8 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 22239 table |
|---|
| GRB_name |
GRB171211A |
| GCN_number |
22239 |
| Detection_method |
Swift-UVOT Other |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22239
SUBJECT: GRB 171211A: Swift/UVOT Upper Limits
DATE: 17/12/11 17:01:01 GMT
FROM: Sam Emery at MSSL-UCL
S.W.K. Emery (UCL-MSSL) and J. D. Gropp (PSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 171211A
362 s after the BAT trigger (Gropp et al., GCN Circ. 22234).
No optical afterglow consistent with the XRT position
(Beardmore et al. GCN Circ. 22236)
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
v 387 6321 491 >19.0
uvw1 436 6731 491 >19.7
uvm2 5503 6526 393 >19.9
uvw2 362 6939 668 >20.2
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.11 in the direction of the burst
(Schlegel et al. 1998).
|
| GCN 22240 table |
|---|
| GRB_name |
GRB171211A |
| GCN_number |
22240 |
| Detection_method |
Swift-XRT Other |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22240
SUBJECT: GRB 171211A: Swift-XRT refined Analysis
DATE: 17/12/11 19:06:04 GMT
FROM: Phil Evans at U of Leicester
K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U.
Leicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo
(INAF-OAB), A. Tohuvavohu (PSU), S. J. LaPorte (PSU), J.A. Kennea (PSU)
and J.D. Gropp report on behalf of the Swift-XRT team:
We have analysed 7.4 ks of XRT data for GRB 171211A (Gropp et al. GCN
Circ. 22234), from 77 s to 24.5 ks after the BAT trigger. The data
comprise 33 s in Windowed Timing (WT) mode (the first 8 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Beardmore
et al. (GCN Circ. 22236).
The light curve can be modelled with a power-law decay with a decay
index of alpha=1.28 (+0.08, -0.07).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.60 (+0.27, -0.23). The
best-fitting absorption column is 1.3 (+1.0, -0.4) x 10^21 cm^-2,
consistent with the Galactic value of 8.9 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 4.3 x 10^-11 (4.9 x
10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.3 (+1.0, -0.4) x 10^21 cm^-2
Galactic foreground: 8.9 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.60 (+0.27, -0.23)
If the light curve continues to decay with a power-law decay index of
1.28, the count rate at T+24 hours will be 6.6 x 10^-4 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.8 x
10^-14 (3.3 x 10^-14) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00796469.
This circular is an official product of the Swift-XRT team.
|
| GCN 22241 table |
|---|
| GRB_name |
GRB171211A |
| GCN_number |
22241 |
| Detection_method |
Swift-BAT Det |
| ra |
98.1540° |
| decl |
-58.6890° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22241
SUBJECT: GRB 171211A: Swift-BAT refined analysis
DATE: 17/12/11 23:19:15 GMT
FROM: Amy Lien at GSFC
H. A. Krimm (NSF/USRA), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), J. D. Gropp (PSU),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
J. P. Norris (BSU), 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-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 171211A (trigger #796469)
(Gropp et al., GCN Circ. 22234). The BAT ground-calculated position is
RA, Dec = 98.154, -58.689 deg which is
RA(J2000) = 06h 32m 36.9s
Dec(J2000) = -58d 41' 19.0"
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 57%.
The mask-weighted light curve shows a single-peaked structure that starts and
peaks at ~ T0, and ends at ~T+3 s. T90 (15-350 keV) is 2.32 +- 0.59 sec
(estimated error including systematics).
The time-averaged spectrum from T+0.03 to T+2.70 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.77 +- 0.21. The fluence in the 15-150 keV band is 2.4 +- 0.3 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.03 sec in the 15-150 keV band
is 2.3 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
The duration and hardness of this burst show it to be intermediate between the
short and long burst populations.
Using a 64-ms binned light curve, the lag analysis finds a lag of
0.144 (+0.106, -0.066) s for the 50-100 keV to 15-25 keV band.
Despite the large error bars due to the weakness of this burst,
this value is more consistent with those of a long GRB.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/796469/BA/
|
| GCN 22250 table |
|---|
| GRB_name |
GRB171211A |
| GCN_number |
22250 |
| Detection_method |
Optical |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22250
SUBJECT: GRB 171211A iTelescope observation
DATE: 17/12/13 03:50:35 GMT
FROM: Takanori Sakamoto at AGU
Y. Kitaoka, T. Sakamoto (AGU)
We observed the field of GRB 171211A detected by Swift (Gropp et al., GCN Circ. 22234)
with the iTelescope.Net (http://www.itelescope.net) T27 (Planewave 27") telescope located
at the AstroCamp Observatory (Siding Spring Observatory, AU). 8 images of 60 sec exposures
were taken in the I filter starting from December 11 on 11:41:37 (UT) about 134 minutes after
the trigger and stopped on 11:54:45 (UT). We do not detect the optical afterglow both in
the individual images and the stacked image at the X-ray afterglow position. The estimated
five sigma upper limit of the combined image (total exposure of 480 sec) is ~17.2 using
the USNO-B1 catalog.
|