| Summary table |
|---|
| Variable |
Value |
Source |
| T0 |
2:12:49 UTC |
GCN_circulars,Swift Det |
| ra |
111.3367° |
Swift |
| decl |
-37.7808° |
Swift |
| pos_error |
2.33e-04° |
Swift |
| T90 |
144.0 s |
Swift |
| T90_start |
2:12:49 UTC |
Swift |
| fluence |
1.80e-06 erg/cm² |
Swift |
| T100 |
144.0 s |
|
| GBM_located |
False |
|
| mjd |
57199.0922337963 |
GCN_circulars,Swift Det |
| IPN table |
|---|
| GRB_name |
GRB150626A |
| ra |
111.3417° |
| decl |
-37.7667° |
| pos_error |
5.00e-02° |
| Swift table |
|---|
| GRB_name |
GRB150626A |
| t_trigger |
2:12:49 UTC |
| ra |
111.3367° |
| decl |
-37.7808° |
| pos_error |
2.33e-04° |
| T90 |
144.0 s |
| fluence |
1.80e-06 erg/cm² |
| GCN 17960 table |
|---|
| GRB_name |
GRB150626A |
| GCN_number |
17960 |
| Detection_method |
Swift Det |
| t_trigger |
2:12:49 UTC |
| ra |
111.3410° |
| decl |
-37.7640° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 17960
SUBJECT: GRB 150626A: Swift detection of a burst
DATE: 15/06/26 02:26:12 GMT
FROM: David Palmer at LANL
T. G. R. Roegiers (PSU), S. D. Barthelmy (GSFC), J. A. Kennea (PSU),
F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and M. H. Siegel (PSU)
report on behalf of the Swift Team:
At 02:12:49 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 150626A (trigger=646603). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 111.341, -37.764 which is
RA(J2000) = 07h 25m 22s
Dec(J2000) = -37d 45' 50"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a complex
structure with a duration of about 30 sec. The peak count rate
was ~2000 counts/sec (15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 02:14:17.3 UT, 87.8 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 111.33758, -37.78043 which
is equivalent to:
RA(J2000) = 07h 25m 21.02s
Dec(J2000) = -37d 46' 49.5"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 59 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 3.51
x 10^21 cm^-2 (Willingale et al. 2013).
The initial flux in the 2.5 s image was 3.03e-09 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 98 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 coverage of the XRT error circle by the 8'x8' region for the list of
sources generated on-board is uncertain because the large number of sources
filled the available telemetry. 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 0.36.
Burst Advocate for this burst is T. G. R. Roegiers (troegiers AT swift.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 17961 table |
|---|
| GRB_name |
GRB150626A |
| GCN_number |
17961 |
| Detection_method |
Swift-XRT Other |
| ra |
111.3364° |
| decl |
-37.7804° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 17961
SUBJECT: GRB 150626A: Prompt enhanced Swift-XRT position
DATE: 15/06/26 03:05:00 GMT
FROM: Phil Evans at U of Leicester
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Using promptly downlinked XRT event data for GRB 150626A, we find an
enhanced XRT position of the afterglow: RA, Dec: 111.3364, -37.7804
which is equivalent to:
RA (J2000) = 07 25 20.74
Dec (J2000) = -37 46 49.5
with an uncertainty of 2.0 arcseconds (radius, 90% confidence).
Analysis of the promptly available data is online at
http://www.swift.ac.uk/sper/646603.
Position enhancement is is described by Goad et al. (2007, A&A, 476,
1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular is an official product of the Swift-XRT team.
|
| GCN 17962 table |
|---|
| GRB_name |
GRB150626A |
| GCN_number |
17962 |
| Detection_method |
Swift-XRT Det |
| ra |
111.3368° |
| decl |
-37.7808° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 17962
SUBJECT: GRB 150626A: Enhanced Swift-XRT position
DATE: 15/06/26 05:37:38 GMT
FROM: Phil Evans at U of Leicester
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester)
report on behalf of the Swift-XRT team.
Using 2166 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 150626A, 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 = 111.33677, -37.78081 which is equivalent
to:
RA (J2000): 07h 25m 20.82s
Dec (J2000): -37d 46' 50.9"
with an uncertainty of 1.8 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 17964 table |
|---|
| GRB_name |
GRB150626A |
| GCN_number |
17964 |
| Detection_method |
Swift-UVOT Other |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 17964
SUBJECT: GRB 150626A: Swift/UVOT Upper Limits
DATE: 15/06/26 13:57:17 GMT
FROM: Massimiliano de Pasquale at IASF-Palermo
M. De Pasquale (UCL-MSSL) and T. Roegiers (PSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 150626A
98 s after the BAT trigger (Roegiers et al., GCN Circ. 17960).
No optical afterglow consistent with the XRT position (Evans
GCN Circ. 17961) 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) exposures and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 98 248 147 >20.4
u_FC 311 561 246 >19.6
white 98 1540 392 >21.1
u 311 1490 324 >19.8
v 641 1590 95 >18.8
b 566 1514 97 >19.7
uw1 690 1465 78 >18.8
um2 665 1440 97 >18.6
uw2 616 1390 97 >19.0
The magnitudes in the table are not corrected for the substantial
Galactic extinction due to the reddening of E(B-V) = 0.37 in the
direction of the burst (Schlegel et al. 1998).
|
| GCN 17965 table |
|---|
| GRB_name |
GRB150626A |
| GCN_number |
17965 |
| Detection_method |
Swift-XRT Other |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 17965
SUBJECT: GRB 150626A: Swift-XRT refined Analysis
DATE: 15/06/26 14:32:33 GMT
FROM: Phil Evans at U of Leicester
V. Mangano (PSU), C. Pagani (U. Leicester), A.P. Beardmore (U.
Leicester), P.A. Evans (U. Leicester), V. D'Elia (ASDC), A. D'ai
(INAF-IASFPA), A. Maselli (INAF-IASFPA), M.C. Stroh (PSU), D.N.
Burrows (PSU) and T.G.R. Roegiers report on behalf of the Swift-XRT
team:
We have analysed 9.2 ks of XRT data for GRB 150626A (Roegiers et al.
GCN Circ. 17960), from 77 s to 31.2 ks after the BAT trigger. The data
comprise 206 s in Windowed Timing (WT) mode (the first 9 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 Evans et
al. (GCN Circ. 17961).
The late-time light curve (from T0+6.3 ks) can be modelled with a
power-law decay with a decay index of alpha=0.65 (+/-0.17).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.08 (+/-0.06). The
best-fitting absorption column is 3.74 (+0.31, -0.24) x 10^21 cm^-2,
consistent with the Galactic value of 3.5 x 10^21 cm^-2 (Willingale et
al. 2013). The PC mode spectrum has a photon index of 2.06 (+0.19,
-0.18) and a best-fitting absorption column of 4.5 (+1.0, -0.9) x 10^21
cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 3.9 x 10^-11 (6.4 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 4.5 (+1.0, -0.9) x 10^21 cm^-2
Galactic foreground: 3.5 x 10^21 cm^-2
Excess significance: 1.8 sigma
Photon index: 2.06 (+0.19, -0.18)
If the light curve continues to decay with a power-law decay index of
0.65, the count rate at T+24 hours will be 0.018 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 6.8 x
10^-13 (1.1 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00646603.
This circular is an official product of the Swift-XRT team.
|
| GCN 17973 table |
|---|
| GRB_name |
GRB150626A |
| GCN_number |
17973 |
| Detection_method |
Swift-BAT Det |
| ra |
111.3530° |
| decl |
-37.8030° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 17973
SUBJECT: GRB 150626A: Swift-BAT refined analysis
DATE: 15/06/27 14:12:33 GMT
FROM: Takanori Sakamoto at AGU
T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. G. R. Roegiers (PSU),
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 150626A (trigger #646603)
(Roegiers, et al., GCN Circ. 17960). The BAT ground-calculated position is
RA, Dec = 111.353, -37.803 deg which is
RA(J2000) = 07h 25m 24.8s
Dec(J2000) = -37d 48' 10.8"
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 37%.
The mask-weighted lightcurve shows overlapping peaks starting at
~T-35 sec, peaking at ~T+2 sec, and ending at ~T+140 sec. T90 (15-350 keV)
is 144 +- 66 sec (estimated error including systematics).
The time-averaged spectrum from T-47.30 to T+144.70 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
2.11 +- 0.19. The fluence in the 15-150 keV band is 1.8 +- 0.2 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T+8.20 sec in the 15-150 keV band
is 0.4 +- 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/646603/BA/
|