- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 13 Jul 05 04:29:14 UT
NOTICE_TYPE: Swift-BAT GRB Position
TRIGGER_NUM: 145675, Seg_Num: 0
GRB_RA: 320.536d {+21h 22m 09s} (J2000),
320.522d {+21h 22m 05s} (current),
320.659d {+21h 22m 38s} (1950)
GRB_DEC: +77.072d {+77d 04' 20"} (J2000),
+77.096d {+77d 05' 45"} (current),
+76.857d {+76d 51' 25"} (1950)
GRB_ERROR: 4.00 [arcmin radius, statistical only]
GRB_INTEN: 3396 [cnts] Image_Peak=215 [image_cnts]
TRIGGER_DUR: 0.512 [sec]
TRIGGER_INDEX: 40 E_range: 25-100 keV
BKG_INTEN: 33380 [cnts]
BKG_TIME: 16128.00 SOD {04:28:48.00} UT
BKG_DUR: 8 [sec]
GRB_DATE: 13564 TJD; 194 DOY; 05/07/13
GRB_TIME: 16142.39 SOD {04:29:02.39} UT
GRB_PHI: 114.33 [deg]
GRB_THETA: 32.96 [deg]
SOLN_STATUS: 0x3
RATE_SIGNIF: 31.27 [sigma]
IMAGE_SIGNIF: 11.32 [sigma]
MERIT_PARAMS: +1 +0 +0 +0 +2 +17 +0 +0 -17 +1
SUN_POSTN: 112.59d {+07h 30m 21s} +21.81d {+21d 48' 53"}
SUN_DIST: 79.69 [deg]
MOON_POSTN: 184.27d {+12h 17m 04s} -0.62d {-00d 37' 20"}
MOON_DIST: 99.90 [deg]
MOON_ILLUM: 36 [%]
GAL_COORDS: 112.15, 18.83 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 56.12, 71.95 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: SWIFT-BAT GRB Coordinates.
COMMENTS: This is a rate trigger.
COMMENTS: A point_source was found.
COMMENTS: This does not match any source in the on-board catalog.
COMMENTS: This does not match any source in the ground catalog.
COMMENTS: This is a GRB.
- red DSS finding chart
ps-file
- GCN/SWIFT NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 13 Jul 05 04:32:44 UT
NOTICE_TYPE: Swift-BAT GRB Lightcurve
TRIGGER_NUM: 145675, Seg_Num: 0
GRB_RA: 320.536d {+21h 22m 09s} (J2000),
320.522d {+21h 22m 05s} (current),
320.659d {+21h 22m 38s} (1950)
GRB_DEC: +77.072d {+77d 04' 20"} (J2000),
+77.096d {+77d 05' 45"} (current),
+76.857d {+76d 51' 25"} (1950)
GRB_DATE: 13564 TJD; 194 DOY; 05/07/13
GRB_TIME: 16142.39 SOD {04:29:02.39} UT
TRIGGER_INDEX: 40
GRB_PHI: 114.33 [deg]
GRB_THETA: 32.96 [deg]
DELTA_TIME: 38.00 [sec]
LC_URL: sw00145675000msb.lc
SUN_POSTN: 112.59d {+07h 30m 21s} +21.81d {+21d 48' 53"}
SUN_DIST: 79.69 [deg]
MOON_POSTN: 184.27d {+12h 17m 04s} -0.62d {-00d 37' 20"}
MOON_DIST: 99.90 [deg]
MOON_ILLUM: 36 [%]
GAL_COORDS: 112.15, 18.83 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 56.12, 71.95 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-BAT GRB Lightcurve.
COMMENTS:
COMMENTS: The next comments were copied from the BAT_POS Notice:
COMMENTS: This is a rate trigger.
COMMENTS: A point_source was found.
COMMENTS: This does not match any source in the on-board catalog.
COMMENTS: This does not match any source in the ground catalog.
COMMENTS: This is a GRB.
- GCN notice #3580
S.A. Yost, E.S. Rykoff, W. Rujopakarn (U Mich), K. Alatalo (Berkeley), B.
Schaefer (Louisiana State) report on behalf of the ROTSE collaboration:
ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB
050713A (Swift trigger 145675), producing images beginning 10.7 s
after the GCN notice time. An automated response took the first image
at 04:29:24.8 UT, 22.4 s after the burst, under fair conditions. We
took 10 5-sec, 10 20-sec and 10 60-sec eposures. These unfiltered
images are calibrated relative to USNO A2.0 (R).
Comparison to the DSS (second epoch) reveals no new sources within the
3-sigma error circle or at the XRT position, for both single images
and coadding into sets of 10. Individual images have limiting
magnitudes ranging from 16.2-17.7; we set the following limit, noting
it is adversely affected by the glare from the nearby bright star SAO
10034 (V=6.6), 67" from the XRT position.
start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd?
--------------------------------------------------------------------
04:29:24.8 4:30:46.8 82 17.7 22.4 Y
- GCN notice #3581
A. Falcone (PSU), D. Palmer (LANL), A. Blustin (MSSL), S. Barthelmy
(GSFC), J. Cummings (GSFC/NRC), H. Krimm (GSFC/USRA), D. Burrows, D.
Morris, C. Gronwall (PSU), C. Markwardt (GSFC/UMD), K. Page
(Leicester), N. Gehrels (GSFC)
At 04:29:02.39 UT, the Swift Burst Alert Telescope (BAT) triggered and
located on-board GRB050713 (trigger=145675). The spacecraft slewed
immediately and was on target at approximately 70 seconds. The
flight-determined location is RA,Dec 320.536,+77.072 {+21h 22m 09s, +77d
04' 20"} (J2000) with an uncertainty of 3 arcmin (radius, stat+sys).
This is a bright burst with a peak count rate of 6000 cts/sec in the
15-350 keV band. The brightest part of the burst duration is ~20
seconds, followed by smaller peaks at T+50, T+65 and T+105 seconds.
The spacecraft slewed immediately and the XRT began observing the burst
at 04:30:14.9 UT (72.6 s after the BAT trigger). XRT found a very
bright, uncataloged, fading X-ray source at:
RA: +21h 22m 09.6s (J2000),
DEC: +77d 04' 30.3" (J2000).
This position is 11 arcseconds from the BAT position. The estimated
uncertainty is 6 arcseconds radius (90% containment).
The Swift Ultra Violet/Optical Telescope (UVOT) observations began at
04:30:17.7 UT, 75 seconds after the BAT trigger. The first data taken
after the spacecraft settled was a 100 sec exposure using the V filter
with the midpoint of the observation at 125 sec after the BAT trigger.
Based on comparisons to the DSS and USNO, we detect no new source at the
XRT position. The 3-sigma upper limit in the V-filter is approximately
17.81 mag.
- GCN notice #3582
D. Malesani (SISSA), P. D'Avanzo (INAF-OAB), E. Palazzi (INAF/IASF, Bo),
G.L. Israel (INAF, OARm), G. Chincarini (Univ. Milano-Bicocca), L.
Stella (INAF, OARm), M. Pedani (INAF, TNG) report on behalf on a larger
collaboration:
We observed the field of GRB 050713 (Falcone et al., GCN 3581) with the
Italian TNG telescope, located at the Canary Islands.
The object was observed after twilight, with a seeing of ~1.4", starting
at 5.274 UT (0.8 h after the GRB). A 2-minutes exposure was acquired in
the I filter.
Inside the XRT error circle, we detect one source at the coordinates
(J2000):
alpha = 21:22:09.6, delta = +77:04:29
with an uncertainty of ~1".
We note two further objects lying just outside the nominal XRT error circle:
1: alpha = 21:22:11.8, delta = +77:04:27
2: alpha = 21:22:08.4, delta = +77:04:39
All these object are fainter than the DSS limit, so we cannot confirm if
any of them is related to the GRB. Further analysis is in progress.
A finding chart can be found here:
http://www.sissa.it/~malesani/GRB/050713/GRB050713_finder.jpg
This message can be cited.
- GCN notice #3583
F. Hearty (Colorado), G. Stringfellow (Colorado), D. Q. Lamb (Chicago), D.
G. York (Chicago), G. Wallerstein (Washington), V. Woolf (Washington), S.
Anderson (Washington), J. Dembicky (APO), J. Barentine (APO), R. McMillan
(APO), B. Ketzeback (APO), and D. Reichart (North Carolina) report on
behalf of the ARC GRB team of the FUN GRB collaboration:
We began observations of the localization of GRB 050713 (Falcone et al.,
GCN 3525) with NIC-FPS on the 3.5m ARC at APO beginning 53 min after the
burst. We detect all three of the candidates identified by Malesani et al.
(GCN 3582) in J,H,Ks in 80-sec integrations, and identify their first
candidate as fading.
NIC-FPS is currently in its commissioning phase.
This message may be cited.
- GCN notice #3584
S. Guziy, A. J. Castro-Tirado, A. de Ugarte Postigo,
J. Gorosabel (IAA-CSIC Granada), J. de Le=F3n Cruz
(IAC Tenerife), O. Bogdanov (Nikolaev State Univ.)
and M. Jel=EDnek (IAA-CSIC),
report:
"Following the detection of GRB 050713 by Swift
(Falcone et al. GCNC 3581), we obtained R-band
images at the 2.5m Nordic Optical Telescope
(+ ALFOSC) starting on June 13.295 UT (about
47 min after the burst onset). We confirm the
presence of an optical source fainter than the DSS-2
limiting magnitude within the reported Swift/XRT
error box, at RA(2000) =3D 21 22 09.53, Dec(2000) =3D
+77 04 29.5 (+/- 0.4"), consistent with the position
reported by Malesani et al. (GCNC 3582). Further
observations are needed in order to confirm if this
is the optical afterglow to GRB 050713. "
This message can be cited.
- GCN notice #3586
XMM-Newton will observe GRB 050713 at location
(RA=21h 22m 09.6s, DEC=+77d 04' 30.3", J2000),
starting at 09:41:00 UT, on July 13, 2005,
for an exposure of 33000 seconds.
- GCN notice #3588
A. Monfardini, A. Gomboc, C. Guidorzi, C.G. Mundell, R.J. Smith,
I. A. Steele, C.J. Mottram, D. Carter, M.F. Bode (Liverpool JMU) report:
"The 2-m Liverpool Telescope followed up robotically the GRB050713
detected by SWIFT (GCN 3581). Three prompt images (2-4 minutes) have
been acquired. No later time observations have been acquired.
We clearly detect the first object suggested by Malesani (GCN 3582) at:
RA = 21:22:09.6, DEC = +77:04:29 (1 arcsec error)
At a mean epoch of 3 minutes after the reported GRB time we preliminarly
estimate a magnitude of r'=19.2 with large errors due to comparison
with USNOB1.0 and magnitude conversion. Further analysis is ongoing.
The afterglow is detected on individual images.
This message can be cited."
- GCN notice #3591
C. Rodgers, E. Hausel, and R. Canterna report on behalf of the Red Buttes Observatory GRB Team as part of the FUN GRB Collaboration. We responded to GRB 050713A (Swift trigger 145675; 4:29 UT) at 04:54 UT with a series of 5 minute R and I exposures centered on the location of the original Swift-BAT GRB position under excellent conditions. We did not observe the afterglow candidate (Malesani GCN 3582) brighter than the following magnitude limits:
UT Time Since Filter Limiting
Start GRB Magnitude
04:56 0:27 R 19.4
05:01 0:31 I 18.2
06:02 1:33 R 19.4
06:08 1:38 I 18.7
10 sigma limiting magnitudes were derived from the USNO-B1.0 catalogue
- GCN notice #3594
N. Loiseau, P. Munuera, R. Gonzalez-Riestra,
M. Santos-Lleo, P. Calderon, and M. Sierra-Gonzalez report:
Quick-Look-Analysis of the XMM-Newton observation of the
GRB 050713A field based on the EPIC PN exposure started
at 10:54:50 UT, shows the presence of a source with
coodinates coincident with SWIFT/XRT coordinates
(Falcone et al., GCN Circ. 3581).
The average EPIC PN source count rate for the first 3ks was
estimated to be 1.0 [counts/sec]
GRB 050713A is also detected with the RGS spectrometer.
- GCN notice #3595
Z.Y. Lin, K.Y. Huang, W.H. Ip (NCU), Y. Urata(RIKEN),
Y. Qiu (BAO), Y.Q. Lou (THCA) on behalf of EAFON report:
"We have imaged the GRB 050713A afterglow position (Malesani et al.;
Hearity et al.; Guziy et al.; and Monfardini et al.) at 10.3 hours
after the burst using Lulin 1-m telescope. The afterglow was not
detected in our R band co-add image (300s x 5 frames). Compare with
USNOB1.0 stars, we estimate the afterglow would be fainter than 22.4
mag during our observations.
This message may be cited."
- GCN notice #3597
D. Palmer (LANL), S. Barthelmy, L. Barbier (GSFC),
J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC),
D. Hullinger (GSFC/UMD), H. Krimm (GSFC/USRA),
C. Markwardt (NASA GSFC/UMD), J. Nousek (PSU), A. Parsons (GSFC),
T. Sakamoto (GSFC/NRC), G. Sato (ISAS), M. Suzuki (Saitama),
M. Tripicco (GSFC/SSAI), J. Tueller (GSFC)
on behalf of the Swift-BAT team:
Using the full data set from the recent telemetry downlink, further
analysis of Swift-BAT GRB 050713A (Trigger #145675; Falcone et al., GCN
Circ 3581) yields a refined position of RA, Dec 320.587, +77.070 {21h
22m 21s, +77d 04' 12"} (J2000) with an uncertainty of 3 arcmin
(radius, 90% confidence, statistical+systematic).
The burst duration (T90) was determined to be 70 +/- 10 seconds (15-350
keV) starting at T-1.0 seconds. There is an initial ~12 second long basically
square hump which shows some structure: three separate peaks of roughly
equal intensity in the 15-50 keV energy band, but falling in intensity with time
above 100 keV. There are additional, much smaller peaks at T-60, T+50
T+65, and T+105 seconds.
The spectrum over the interval from T-70 to T+121 seconds can be fit
with a power law with photon index 1.58 +/- 0.07 and yields a fluence of
9.1 +/- 0.6 X 10^-6 erg/cm^2 in the 15-350 keV band. The peak flux
in a 1-sec wide window starting at T+1.2 seconds is 6.0 +/- 0.4 ph/cm^2/sec.
- GCN notice #3598
A. Blustin (MSSL), A. Falcone (PSU), D. Hinshaw
(GSFC-SPSYS), P. Meszaros (PSU) report on behalf of
the Swift UVOT team:
Using summed images from Swift/UVOT of the field of
GRB 050713A, taken from 75 seconds after the BAT
trigger, no new source is detected within the XRT
error circle (Falcone et al., GCN 3581) in any of
the six filters down to the following 3-sigma
magnitude upper limits:
Filter Exposure (s) T_mid (s) 3-sig limit
V 129 252 17.98
B 36 351 18.08
U 39 309 17.81
UVW1 39 325 16.85
UVM2 39 311 17.13
UVW2 29 326 17.08
where T_mid is the mid-point of the summed observation.
The image background is significantly higher than
expected at this location due to the proximity of a
6.56 V magnitude star (HD 204408).
We caution that the instrument is not yet fully
calibrated and that the magnitude limits presented here
may need to be refined.
- GCN notice #3604
J. Wren, W.T. Vestrand, P. Wozniak, R. White, S. Evans report
on behalf of the RAPTOR team.
The RAPTOR-S telescope at Los Alamos National Laboratory began
imaging the field of GRB 050713A (Swift trigger 145675) 22.4
seconds after the GRB trigger -- before the end of the interval
of prompt gamma-ray emission (Falcone et al. GCN circ 3581).
At the location of the fading optical and NIR counterpart identified
in later images by Malesani et al. (GCN circ 3582) and Hearty et al.
(GCN circ 3583), respectively, we detected a transient optical
counterpart. In a stack of eight 10 second unfiltered images
starting at 04:29:24.8 UT (with midpoint at 99.3 s after the GRB
trigger), we measured the optical transient to have a R-band
magnitude of 18.4 (+/- 0.18). Our preliminary transformation to
R-band magnitudes was based on field stars from the USNO-B1 catalog.
- GCN notice #3606
D. Morris, D. N. Burrows, A. Falcone, P. Roming (PSU), K. Page, M. Goad (=
Leicester), M. Trippico (GSFC-SSAI), F. Marshall=20
and N. Gehrels (GSFC) report on behalf of the Swift XRT team:
We have analysed the first three orbits of data for GRB050713a (GCN 3581,=
=20
Falcone et al., 2005). Using xrtcentoid, the refined position is:
RA(J2000) =3D 21h 22m 09.9s
Dec(J2000) =3D +77d 04' 24.2"
RA(J2000) =3D 320.5411
Dec(J2000) =3D +77.0734
with an uncertainty of 6 arcsec. This is 6 arcsec from the original=20
XRT position (GCN 3581, Falcone et al., 2005).
The XRT began taking data at 04:30:14UT, just 72 seconds after the BAT tr=
igger=20
and while the prompt gamma-ray emission was still in progress. The early =
XRT
lightcurve shows flares coincident with the BAT reported peaks (GCN 3597,
Palmer et al., 2005) at T+65 (caught on the tail end of the peak) and at =
T+105.
A decay rate has not been determined for the first orbit due to the flari=
ng
nature of the emission at that point, with count rates varying between 10=
-300 cts/s.
Data from the 2nd and 3rd orbits span the timeframe 5ks-10ks after the tr=
igger and
show a smoothly decaying afterglow at much lower flux, fit well by a powe=
rlaw with
alpha =3D 0.82+/- 0.11.
The spectrum from all 3 orbits are well fit by an absorbed power-law with=
NH significantly=20
greater than the galactic value of 1.1e21
gamma=3D2.1+/-0.05
NH=3D4.5e21 =B1 0.5e21
The count rate at 5000s after the trigger is ~0.35 cts/s which converts to
an
unabsorbed flux of 2.24e-11 ergs cm^-2 s^-1.
- GCN notice #3619
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and
T. Cline on behalf of the Konus-Wind team report:
The long GRB 050713A (Swift-BAT trigger #145675;=20
Falcone et al., GCN 3581, Palmer et al., GCN 3597)
triggered Konus-Wind at T0=3D16141.745 s UT (04:29:01.745).
As observed by Konus-Wind it had a duration of ~16 s,
fluence (1.22 =B1 0.08)10-5 erg/cm2,
peak flux on 64-ms time scale (1.7 =B1 0.4)10-6 erg/cm2 s
(both in the 20 keV - 4 MeV energy range).
Konus-Wind did not detect additional smaller peaks,
reported by Swift-BAT.
Probably they were too weak to be detected by Konus-Wind.
The spectrum integrated over the most instense part of the GRB
(from T0 to T0+8.448 s) is well fitted (in 20 keV-4 MeV range)
by a power law with exponential cutoff model:
dN/dE ~ E^(-alpha) exp(-E/E0)=20
with alpha =3D 1.12 +/- 0.08,
and E0 =3D 355 =B1 70 keV.
The peak energy Ep =3D 312 =B1 50 keV.
Valentin Pal'shin
Ioffe Physico-Technical Institute
Laboratory for Experimental Astrophysics
26 Polytekhnicheskaya, St Petersburg 194021,
Russian Federation
email: val@mail.ioffe.ru
Tel: (7)-812-2479177
Fax: (7)-812-2471963
- GCN notice #3648
P. B. Cameron reports on behalf of the Caltech-NRAO-Carnegie
collaboration:
"We observed the field of GRB050713a (GCN 3581) with the Very Large Array
at 8.5 GHz on July 17.51. No radio source is detected at the position of
the optical/NIR transient (GCN 3582, 3583) with a 2-sigma upper limit of
96 uJy.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."
- GCN notice #3695
Andrea De Luca (IASF Mi) on behalf of a larger collaboraton
report:
We have analyzed the data from the XMM-Newton observation
of GRB050713A, discovered by Swift on 2005, July 13 at
04:29:02.39 UT (Falcone et al., GCN3581).
The XMM-Newton observation started on 2005, July 13 at
10:18 UT and lasted for 30.7 ks. We report here on the
analysis of data collected with the EPIC/pn detector,
which started observing the field at 10:54 UT (~6h 20min
after the GRB).
As reported by Loiseau et al. (GCN3594), the afterglow of
GRB050713A is clearly detected in the pn image, at a
position fully consistent with the refined Swift/XRT one
(Morris et al., GCN3606).
Extracting source events from a circle of 25 arcsec radius
(containing ~80% of the total counts), the time-averaged,
background-subtracted count rate in the 0.2-8 keV range
is 0.547+/-0.005 cts/s.
The afterglow is clearly seen to fade along the XMM-Newton
observation, spanning the time range 23.5-51.5 ks after
the GRB. The background-subtracted light curve (0.5-5 keV)
is well fitted (reduced chi2=0.9, 26 d.o.f.) by a power law
decay with index delta=1.45+/-0.07 (90% c.l.).
The afterglow decay has significantly steepened with
respect to the epoch of the earlier Swift observation:
Morris et al. (GCN 3606) observed an index delta=0.82+/-0.11
in the time range 5-10 ks after the burst using Swift/XRT data.
This implies the presence of a break in the afterglow X-ray
light curve between 10 ks and 23.5 ks from the GRB.
We extracted the time-averaged spectrum and generated ad-hoc
response and effective area files. We quote here errors at
90% level for a single interesting parameter, unless otherwise
specified.
A fit in the energy range 0.2-8 keV with an absorbed power
law model yields a reduced chi2 of 1.25 for 172 d.o.f.
The resulting NH=(3.25+/-0.15)x10^21 cm^-2 is higher than
the expected Galactic value in the burst direction (NH=1.1x10^21
cm^-2, Dickey & Lockman, 1990); the best fitting power law photon
index is Gamma=2.16+/-0.05.
Such results are consistent with the XRT ones (Morris et al.,
GCN 3606), which implies no significant spectral evolution with
respect to the earlier phase of the afterglow.
A better fit to the pn spectrum (reduced chi2=0.97, 171 dof)
may be obtained fixing the NH to the expected Galactic value
(NH=1.1x10^21 cm^-2) and adding a neutral, redshifted absorber
component to the spectral model. With a simple F-test we evaluate
the chance occurrence probability of the improvement to be
of 5x10^-11. The best fit value for the intrinsic NH is 4.0x10^21
cm^-2, while the best fit value for the redshift z is 0.55.
At 90% c.l. for 2 parameters, we obtain the following ranges:
intrinsic NH=(0.4-3.2)x10^22 cm^-2; redshift z=(0.4-2.6).
Using such model, the resulting power law photon index is
Gamma=2.04+/-0.05.
The observed flux is of 2.2x10^-12 erg cm^-2 s^-1 in 0.2-10 keV;
the corresponding unabsorbed flux is of 3.8x10^-12 erg cm^-2 s^-1.
As a last step, we divided the pn dataset into two time intervals
of ~9500 s and ~14600 s (each containing about half of the counts
from the afterglow) and we repeated the spectral analysis.
We found no significant spectral changes in the two considered
intervals.
- GCN notice #3703
D. Morris, D. N. Burrows, A. Falcone, P. Roming (PSU), K. Page, M. Goad
(Leicester), M. Trippico (GSFC-SSAI), F. Marshall and N. Gehrels (GSFC)
report on behalf of the Swift XRT team:
The Swift XRT has continued to monitor the light curve of GRB050713a with
data taken as late as 10 days after the burst trigger.
We confirm the XMM observation of a decaying lightcurve with powerlaw slope
consistent with alpha=1.45 during the epoch 20ks-50ks after the burst
trigger (De Luca et al, GCN3695). We note, however, that the entire XRT
dataset, from 4ks to 1000ks after the burst trigger, shows a powerlaw shape
very well fit by an alpha=1.15 decay index, with no evidence for a jet
break. We suggest that the steeper slope seen between 20ks-50ks may be due
to flaring activity.
The XRT count rate during the last observation, on July 23rd, was 6e-4
cts/s, equivalent to a flux of 4e-14 ergs/cm^2/s
- GCN notice #3747
TITLE: GCN GRB OBSERVATION REPORT
SUBJECT: GRB 050713A: Observation at very high energy by MAGIC
N. Galante and Stamerra (INFN/Siena)
D. Bastieri, M. Fagiolini, M. Gaug, M. Garczarczyk, T. Lenisa, F. Longo,
K. Mannheim, S. Mizobuchi, A. Moralejo, R. Paoletti, L. Peruzzo, A Piccioli, S.
Shore
on behalf of the MAGIC Collaboration:
"The MAGIC Cherenkov telescope in La Palma has observed GRB050713A 40s after
T0.
This observation, started 20 seconds after the alert given
by Swift (Trigger #145675; Falcone et al., GCN Circ 3581), thanks to the
capability of fast pointing by MAGIC and to the prompt reaction by the
operators; it
overlapped for around 30 seconds with Swift during the main burst,
and lasted 2400 s. The first look at the MAGIC data did not reveal strong gamma
ray
emission above 175GeV. The flux limit derived at very
high energies by MAGIC is 2-3 orders of magnitude lower than the extrapolation
from
the X band [1]. A detailed analysis is in progress. To our knowledge, this is
the first
simultaneous observation of a GRB in the X band and in the HE gamma region."
[1] A. Falcone, private communication.
- astro-ph/0602231 from 10 Feb 2006
Albert etal: Flux upper limit of gamma-ray emission by GRB050713a from
MAGIC Telescope observations
The long-duration GRB050713a was observed by the MAGIC Telescope, 40 seconds after the burst onset, and followed up for 37 minutes, until twilight. The observation, triggered by a SWIFT alert, covered energies above ~175 GeV. Using standard MAGIC analysis, no evidence for a gamma signal was found. As the redshift of the GRB was not measured directly, the flux upper limit, estimated by MAGIC, is still compatible with the assumption of an unbroken power-law spectrum extending from a few hundred keV to our energy range.
- astro-ph/0602387 from 17 Feb 2006
Guetta:
We present a detailed study of the spectral and temporal properties of the
X-ray and optical emission of GRB050713a up to 0.5 day after the main GRB
event. The X-ray light curve exhibits large amplitude variations with several
rebrightenings superposed on the underlying three-segment broken powerlaw that
is often seen in Swift GRBs. Our time-resolved spectral analysis supports the
interpretation of a long-lived central engine, with rebrightenings consistent
with energy injection in refreshed shocks as slower shells generated in the
central engine prompt phase catch up with the afterglow shock at later times.
Our sparsely-sampled light curve of the optical afterglow can be fitted with a
single power law without large flares. The optical decay index appears flatter
than the X-ray one, especially at later times.
- astro-ph/0602490 from
22 Feb 2006
Morris:
Swift discovered GRB 050713A and slewed promptly to begin observing with its
narrow field instruments 72.6 seconds after the burst onset, while the prompt
gamma-ray emission was still detectable in the BAT. Simultaneous emission from
two flares is detected in the BAT and XRT. This burst marks just the second
time that the BAT and XRT have simultaneously detected emission from a burst
and the first time that both instruments have produced a well sampled,
simultaneous dataset covering multiple X-ray flares. The temporal rise and
decay parameters of the flares are consistent with the internal shock
mechanism. In addition to the Swift coverage of GRB 050713A, we report on the
Konus-Wind (K-W) detection of the prompt emission in the energy range 18-1150
keV, an upper limiting GeV measurement of the prompt emission made by the MAGIC
imaging atmospheric Cherenkov telescope and XMM-Newton observations of the
afterglow. Simultaneous observation between Swift XRT and XMM-Newton produce
consistent results, showing a break in the lightcurve at T+~15ks. Together,
these four observatories provide unusually broad spectral coverage of the
prompt emission and detailed X-ray follow-up of the afterglow for two weeks
after the burst trigger. Simultaneous spectral fits of K-W with BAT and BAT
with XRT data indicate that an absorbed broken powerlaw is often a better fit
to GRB flares than a simple absorbed powerlaw. These spectral results together
with the rapid temporal rise and decay of the flares suggest that flares are
produced in internal shocks due to late time central engine activity.
- Limit on redshift of host of <3.6 due to g-R = 0.4 color.
See
AJ 138 (2009) 1690
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