GRB 090529A, GRB 090529
GCN Circular 9612
Subject
GRB 090529: CrAO optical upper limit
Date
2009-07-03T22:27:56Z (17 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
D. Shakhovkoy, V. Rumyantsev (CrAO), A. Pozanenko (IKI) report on behalf of
larger GRB follow-up collaboration:
We observed the field of the Swift GRB 090529 (Sakamoto et al. GCN 9430)
with AZT-11 telescope of CrAO between (UT) May 29 18:41 -- 19:42 under poor
weather conditions. We do not detect optical afterglow (Xin et al. GCN
9431). Upper limit of a stacked image based on USNO-B1.0 star (RA=14 09
47.65 Dec=+24 27 44.30) assuming I=17.54 is following:
T0+ Filter, Exposure, mag.
(d) (s)
0.2075 I 20x180 > 20.3
GCN Circular 9611
Subject
GRB 090529: MTM-500 optical observations
Date
2009-07-03T22:16:50Z (17 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Volnova (SAI MSU), K. Naumov, V. Kouprianov, A. Devyatkin (Pulkovo
Observatory), A. Pozanenko (IKI) report on behalf of larger GRB follow-up
collaboration:
We observed the field of the Swift GRB 090529 (Sakamoto et al. GCN 9430)
with MTM-500 (0.5m) telescope of Kislovodsk solar station (43d 44.77' N,
42d 31.42' W) of the Pulkovo observatory in two series in R-filter starting
May 29 (UT) 19:58. We do not detect optical afterglow
(Xin et al. GCN 9431). The upper limits of combined images based on
USNO-B1.0 are following:
T0+ Filter, Exposure, mag.,
(d) (s)
0.2817 R 60x60 > 19.3
0.3324 R 55x60 > 19.4
GCN Circular 9610
Subject
GRB 090529: Mt.Terskol optical observations
Date
2009-07-03T22:10:53Z (17 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
M. Andreev, A. Sergeev (Terskol Branch of Institute of Astronomy), A.
Pozanenko (IKI) on behalf of larger GRB follow up collaboration report:
We report a photometry of the optical afterglow (Xin et al. GCN 9431) of
the Swift GRB 090529 (Sakamoto et al. GCN 9430) observed with the Z-600
telescope of Mt.Terskol observatory in R-filter (Andreev et al, GCN 9437).
The photometry is based on reference star USNO-B1.0 1144-0210607 (J2000)
14 09 58.32 +24 27 35.6), assuming R=16.46:
T0+ Filter, Exposure, mag.,
(d) (s)
0.2420 R 20x120 21.13 +/- 0.2
GCN Circular 9485
Subject
GRB 090529A: RTT150 Optical Observations
Date
2009-06-03T15:51:34Z (17 years ago)
From
Solen Balman at METU <solen@astroa.physics.metu.edu.tr>
S. Balman (METU), M. Parmaksizoglu (TUG)
Z. Eker (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.)
I. Bikmaev, N. Sakhibullin (KSU/AST)
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI),
report:
We observed the field of GRB090529A (trigger=353540, Sakamato et al. 2009
GCN Circ. 9430, also GCN Circ. 9431-9436,9448,9449,9457) with the
Russian-Turkish 1.5-m telescope (RTT150, Bakirlitepe, TUBITAK National
Observatory, Turkey) on 30 May starting at 00:09:01.86 UT about 9.94 hours
(0.414 d) after the burst
using the TFOSC CCD (burst detected at 14:12:35 UT with Swift Burst Alert
Telescope (BAT)).
We obtained one 900 sec exposure using the R band filter (Bessell filter). We
found the afterglow candidate at the location designated by the Swift XRT
position given by Osborne et al. 2009 GCN Circ. 9433. We performed PSF
photometry using DAOPHOT within MIDAS software on the 13.3 by 13.3 arcmin field
around the afterglow candidate. We calibrated the R band magnitude
using the same USNO-B1 reference star noted by Kann et al. 2009 GCN Circ.
9436. The GRB090529 afterglow candidate is detected at R = 21.2+/-0.2 mag.
This message can be cited.
[GCN OPS NOTE(03jun09): Per author's request, the Subject line was changed.]
GCN Circular 9482
Subject
GRB090529: Further NOT optical observations
Date
2009-06-02T21:57:20Z (17 years ago)
From
Dong Xu at DARK,NBI <dong@astro.ku.dk>
D. Xu, G. Leloudas, D. Malesani, J. P. U. Fynbo, J. Maund (DARK/NBI), P.
Jakobsson (Univ. Iceland), and T. Liimets (NOT & Tartu Obs.) report on
behalf of a larger collaboration:
We continued to observe the field of GRB 090529 (Sakamoto et al., GCN
9430) with the Nordic Optical Telescope equipped with ALFOSC. We
obtained 3x600 s R-band frames staring on June 01, 21:26:31 UT and
ending on June 01, 22:00:52 UT. The mid-exposure time is 3.31 days after
the burst.
The optical afterglow (Xin et al., GCN 9431; Schady et al., GCN 9435) is
still detected in the stacked frame. Using the same reference star as in
Kann et al. (GCN 9436) and in Leloudas et al. (GCN 9453), we obtain
R=22.8+/-0.1 for the afterglow.
Measurements by Kann et al. (0.3 day after the burst) and Leloudas et
al. (1.29 days after the burst) indicate an optical power-law decay
index of alpha1=0.72. Our new observation indicates that the optical
decay became even slower, with an index of alpha2=0.3 between our two
obs epochs. In contrast, during the whole period of 0.3 - 3.31 days the
X-ray afterglow decays with the index of ~1.0 (ref, Evans et al. 2009).
The slow optical decay may be also due to the presence of a fairly
bright host galaxy.
Further optical observations are encouraged.
GCN Circular 9467
Subject
GRB 090529: MITSuME optical observation
Date
2009-06-01T07:55:52Z (17 years ago)
From
Michitoshi Yoshida at Okayama Astrophysical Obs <yoshida@oao.nao.ac.jp>
M. Yoshida, D. Kuroda, K. Yanagisawa, Y. Shimizu, S. Nagayama,
H. Toda (OAO, NAOJ) and N. Kawai (Tokyo Tech) report on behalf
of the MITSuME collaboration:
We observed the field of GRB 090529 (Sakamoto et al. GCN 9430)
with optical three color (g', Rc and Ic) CCD camera attached to
the MITSuME 50cm telescope of Okayama Astrophysical Observatory.
The observation started on 2009-05-29 14:51:47 UT. We found a
faint source at the UVOT position reported by Schady et al. (GCN
9435) in g' band.
Photometric results are listed below. We used USNO B1 catalog
for flux calibration.
#PDAY MID-UT T-EXP g' g'_err Rc Ic
----------------------------------------------------------
0.03564 15:03:55 1200sec 20.3 0.4 >19.7 >18.9
----------------------------------------------------------
GCN Circular 9457
Subject
GRB 090529: VLT spectroscopic redshift
Date
2009-05-31T10:39:47Z (17 years ago)
From
Valerio D'Elia at INAF-OAR <delia@oa-roma.inaf.it>
D. Malesani, J. P. U. Fynbo, (DARK/NBI), V. D'Elia (INAF/OAR),
A. de Ugarte Postigo (ESO), P. Jakobsson (U. Iceland),
C. C. Thoene (INAF/OAB), report on behalf of a larger collaboration:
Using FORS2 on the ESO Very Large Telescope, we have obtained
low-resolution spectra (2 x 30 min) of the optical afterglow of GRB
090529 (Sakamoto et al., GCN 9430; Xin et al., GCN 9431) with the grism
300V, covering the wavelength range 3500-9200 AA. In the acquisition
image the afterglow has a magnitude of R ~ 22.60 +-0.05. The first spectrum
was taken starting on May 31.0778 UT (1.48 days after the GRB).
In a preliminary analysis we detect strong absorption around 4416 AA
which we interpret as Lyman-alpha at a redshift of
z = 2.63. This value is supported by the detection of several metal
absorption features, e.g., SiII 1526, CII 1335, SiII 1402 and CIV 1549, all
at the common z=2.625, which we interpret as the redshift of the GRB.
We thank the Paranal staff for excellent support, in particular
Thomas Szeifert, Alain Smette, and Karla Aubel. We are also grateful to Lipin Xin
for providing us with a finding chart.
-------------------------------------------------
This mail sent through IMP: http://horde.org/imp/
GCN Circular 9453
Subject
GRB 090529: NOT optical observations
Date
2009-05-30T23:53:10Z (17 years ago)
From
Giorgos Leloudas at Dark Cosmology Centre <giorgos@dark-cosmology.dk>
G. Leloudas, D. Malesani, D. Xu, J.P.U. Fynbo (DARK/NBI), P.
Jakobsson (Univ. Iceland),
M. E. Brown (Caltech), E.L. Schaller (Univ. Hawaii) and T. Liimets
(NOT & Tartu Obs.)
report on behalf of a larger collaboration:
We observed the field of GRB 090529 (Sakamoto et al., GCN 9430) with
the Nordic Optical Telescope equipped with MOSCA.
3x600s R-band frames were obtained starting on May 30, 21:22 UT, 1.29
days after the GRB.
The optical afterglow (Xin et al., GCN 9431; Schady et al., GCN 9435)
is well detected in our images. Using the same reference star as in
Kann et al. (GCN 9436), we obtain R=22.5 for the afterglow.
Comparison with the measurement by Kann et al., taken 0.3 days after
the GRB, provides a decay index alpha = 0.72, assuming a power-law F
(t) propto t^-alpha.
GCN Circular 9449
Subject
GRB 090529: Swift-XRT refined analysis
Date
2009-05-30T16:48:02Z (17 years ago)
From
Boris Sbarufatti at INAF-IASF-Pa <sbarufatti@ifc.inaf.it>
Sbarufatti B., Mangano V. (INAF-IASFPA) and T. Sakamoto (NASA/UMBC)
report on behalf of the Swift Team:
We have analyzed the first eleven orbits of Swift-XRT data of
GRB 090529 (trigger 353540; Sakamoto, et al., GCN Circ. 9430),
comprising 148 s taken in Windowed Timing (WT) mode, from T+203 s
to T+352 s, and 8.2 ks in Photon Counting (PC)
mode from T+353 s to T+46.7 ks.
The best position for the X-ray afterglow is the XRT UVOT-enhanced
position:RA, Dec = 212.46850, +24.45919 which is equivalent
to:
RA (J2000): 14h 09m 52.44s
Dec (J2000): +24d 27' 33.1"
with an uncertainty of 1.8 arcsec (radius, 90% confidence), as given
by Osborne, et al., GCN Circ 9433.
The 0.3-10 keV X-ray light curve is best fitted by a broken power-law
wit early decay index -3.5+/-0.1, late decay index -0.7+/-0.2 and the
break at (1100+180-140) s after the trigger. Faint flaring activity is
detected along the decay. If decaying at the present rate, the
predicted rate for T+ 48h is 2.8e-3 counts/s. However, we remark that
a second break followed by a steepening of the light-curve is
expected. The issue will be clarified when new data from the Swift
observations (resumed today at 14:35 UT) will be available.
The average spectrum of the steep decay part of the afterglow (WT + PC
from T+203s to T+1.1 ks) is best fit by a power-law with indices
2.5+/-0.12 for the WT data and 2.2+/-0.15 for the PC data. The
absorbing column is NH = (2.3-1.5+1.7)E20 cm^-2 slightly in excess
with respect to the Galactic value of 1.61E20 cm^-2 (Kalberla et
al. 2005). The average observed (unabsorbed) fluxes are
4.5(5.1)E-10 ergs cm^-2 s^-1 for the WT data and 1.5(1.6)E-11 for the
PC data.
The average spectrum of the flat decay part of the afterglow,
consisting of 7.5 ks of PC data, observed from T+1.1 ks to T+46.7 ks
(containing 120 photons) was fitted using Cash statistics with an
absorbed power-law model. The absorbing column NH is (9 -7 +9)E20
cm^-2, consistent with the Galactic value, the photon index is
2.3+/-0.5. The observed (unabsorbed) flux is 5.3(7.2)E-13 ergs cm^-2
s^-1. The C-statistic is 66.4 with 101 bins.
The count-rate to flux conversion factor is 4.7E-11.
All quoted errors are at 90% confidence level.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00353540.
This circular is an official product of the Swift-XRT team.
GCN Circular 9448
Subject
GRB 090529: OSN optical observations
Date
2009-05-30T16:04:33Z (17 years ago)
From
Javier Gorosabel at Danish Space Res Inst <jgu@space.dtu.dk>
J. Gorosabel (IAA-CSIC), A. de Ugarte Postigo (ESO, Santiago),
F.J. Aceituno (OSN, IAA-CSIC), A.J. Castro-Tirado (IAA-CSIC), report
on behalf of a larger collaboration:
"We carried out R-band observations of the GRB 090529 XRT error circle
(Sakamoto et al. GCN 9430; Osborne et al. GCN 9433) with the 1.5m OSN
telescope. On May 29.87-29.93 UT (0.27-0.33 days afer the GRB) we detected
the optical afterglow (Xin et al. GCN 9431) at R=21.44+/-0.06, against the
same reference star used by Kann et al. (GCN 9436)."
This message can be quoted.
GCN Circular 9437
Subject
GRB 090529: optical observations
Date
2009-05-30T01:39:58Z (17 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
M. Andreev, A. Sergeev (Terskol Branch of Institute of Astronomy), A.
Pozanenko (IKI) on behalf of larger GRB follow up collaboration report:
We observed the optical afterglow (Xin et al. GCN 9431) of the Swift GRB
090529 (Sakamoto et al. GCN 9430) with the Z-600 telescope of Mt.Terskol
observatory in R-filter between (UT) May 29 19:40 -- 20:20. In a combined
image (20x120 s) we clearly detect the afterglow at the position (J2000)
RA=14 09 52.55 Dec=+24 27 31.2 which is comparable with the afterglow
position (Schady et al. GCN 9435, Kann et al. GCN 9436). The combined image
finding chart can be found at
http://grb.rssi.ru/GRB090529/GRB090529_Z600.JPG
The photometry of the afterglow is undergoing.
GCN Circular 9436
Subject
GRB 090529: TLS Afterglow Observations
Date
2009-05-30T00:12:12Z (17 years ago)
From
Alexander Kann at TLS Tautenburg <kann@tls-tautenburg.de>
D. A. Kann, U. Laux and B. Stecklum (TLS Tautenburg) report:
We observed the optical afterglow (Xin et al., GCN 9431) of the Swift GRB
090529 (Sakamoto et al., GCN 9430) with the 1.34m Schmidt telescope of the
Thueringer Landessternwarte Tautenburg, Germany. Observations began at
twilight, which, together with the setting moon, caused an elevated sky
background. Airmass was low and conditions were excellent until clouds
came in during the last Rc image. We obtained 6 x 300 sec dithered images
in the Ic band and 3 x 600 sec images in the Rc band. The afterglow is
very faintly visible on several Ic frames, clearly visible on the first
two Rc frames and hardly visible on the last Rc frame.
Using the USNOB1.0 catalog as a reference, we derive the following
position (J2000) for the afterglow:
RA = 14:09:52.53
Dec. = +24:27:32.77
with an error of 0".5. This position lies 0".7 from the UVOT position
(Schady et al., GCN 9435), in full agreement with it.
We find several sources of roughly similar magnitude within 10" of the
afterglow. These may slightly affect the photometry.
To calibrate, we use the isolated star with USNO catalog # 1144-0210566 at
position
RA = 14:09:47.50
Dec. = +24:27:44.5
which has R2 = 18.32 mag and I = 17.54 mag. (Note that it is 0.54 mag
brighter in R1.)
We derive the following magnitudes 0.3 days after the GRB:
time (d) Mag dMag Exposure Filter
0.287871 20.98 0.13 6 x 300 Ic
0.304668 21.39 0.12 1 x 600 Rc
0.312191 21.40 0.12 1 x 600 Rc
0.319703 21.47 0.35 1 x 600 Rc
Compared to the magnitude found by Xin et al., GCN 9431, this indicates
the afterglow has faded by two magnitudes. The normal Rc - Ic color as
well as the confirmation by Swift UVOT of a rising afterglow (Schady et
al., GCN 9435) implies that it is not overly reddened, an alternate
explanation by Holland et al., GCN 9432.
No further observations are planned.
This message may be cited.
GCN Circular 9435
Subject
GRB090529: UVOT/Swift detection of a brightening optical afterglow
Date
2009-05-29T22:12:44Z (17 years ago)
From
Patricia Schady at MSSL/Swift <ps@mssl.ucl.ac.uk>
P. Schady (MSSL-UCL), T. Sakamoto (NASA/UMBC), S. T. Holland
(CRESST/GSFC/USRA) 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 090529 206s
after the BAT trigger (Sakamoto et al., GCN Circ. 9430) and no new source
was detected within the XRT position in the first white finding chart (fc)
(Sakamoto et al., GCN Circ. 9430; Holland et al., GCN Circ. 9432).
However, a new source is detected within the refined XRT error circle
(Osborne et al., GCN Circ. 9433) in a second white finding chart, taken at
883s after the BAT trigger, as well as in a co-added b-band exposure at
RA (J2000) 14:09:52.56 = 212.46892 (deg)
Dec (J2000) +24:27:32.2 = +24.45892 (deg)
with an estimated uncertainty of 0.7 arcsec (radius, 90% confidence,
statistical + systematic). This source detection is consistent with the
white band detection reported by Xin et al. (GCN Circ. 9431). We note that
there is weak evidence that the source could be extended.
The magnitudes and 3-sigma upper limits for the observations currently
available are as follows:
Filter T_start(s) T_stop(s) Exp(s) Mag/3-sigma UL
white_fc1 206 355 147 > 21.09
white_fc2 883 1032 147 20.81 +/- 0.22
white 1185 2587 175 21.55 +/- 0.31
v 363 2637 253 > 20.24
b 461 2564 233 20.97 +/- 0.36
b 2716 2824 107 > 20.70
u 436 2691 253 > 20.87
uvw1 412 2667 156 > 20.60
uvm2 387 2661 253 > 20.20
uvw2 510 2594 253 > 20.65
The values quoted above are not corrected for the Galactic extinction due
to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel
et al. 1998). The photometry is on the UVOT photometric system described
in Poole et al. (2008, MNRAS, 383, 627).
GCN Circular 9434
Subject
GRB 090529: Swift-BAT refined analysis
Date
2009-05-29T20:10:34Z (17 years ago)
From
Hans Krimm at NASA-GSFC <hans.krimm@nasa.gov>
C. B. Markwardt (GSFC/UMD), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC),
T. N. Ukwatta (GWU) (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 090529 (trigger #353540)
(Sakamoto, et al., GCN Circ. 9430). The BAT ground-calculated position is
RA, Dec = 212.446, 24.450 deg which is
RA(J2000) = 14h 09m 47.1s
Dec(J2000) = +24d 26' 58.5"
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 83%.
The mask-weighted light curve shows that the burst was in progress when it
came into the BAT field of view at ~T-50 sec, following a pre-planned slew.
The detectable part of the light curve shows an exponentially falling rate,
which some possible superimposed peaks at ~T-45, ~T-25 and ~T-15 sec. The
count rate is down to background by T+50 seconds. Given that we did not
observe the start of the burst, we can only provide a lower limit to T90:
T90 (15-350 keV) is > 100 sec.
The time-averaged spectrum from T-49.0 to T+39.3 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
2.00 +- 0.3. The fluence in the 15-150 keV band is 6.8 +- 1.7 x 10-7 erg/cm2.
The 1-sec peak photon flux measured from T-50.0 sec in the 15-150 keV band
is 0.4 +- 0.1 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/353540/BA/
GCN Circular 9433
Subject
GRB 090529: Enhanced Swift-XRT position
Date
2009-05-29T19:11:24Z (17 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester)
report on behalf of the Swift-XRT team.
Using 2467 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 090529, 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 = 212.46850, +24.45919 which is equivalent
to:
RA (J2000): 14h 09m 52.44s
Dec (J2000): +24d 27' 33.1"
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, arXiv:0812.3662).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
GCN Circular 9432
Subject
GRB 090529: Preliminary Swift/UVOT Upper Limit
Date
2009-05-29T17:12:13Z (17 years ago)
From
Stephen Holland at USRA/NASA/GSFC/SSC <sholland@milkyway.gsfc.nasa.gov>
S. T. Holland (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC),
P. Schady (MSSL-UCL), and T. Sakamoto (NASA/UMBC) report on the behalf
of the Swift UVOT team:
The Swift/UVOT took a 150 s exposure of the field of GRB 090529
with its white filter starting 204 s after the BAT trigger (Sakamoto,
et al., 2009, GCN Circ. 9430). The preliminary 3-sigma upper limit at
the XRT position is white > 20.3. This upper limit has not been
corrected for the expected Galactic extinction along the line of sight
corresponding to a reddening of E_{B-V} = 0.02 mag (Schlegel, et al.,
1998, ApJS, 500, 525). The photometry is on the UVOT photometric
system described in Poole et al. (2008, MNRAS, 383, 627).
The non-detection in the white filter at 204 s, combined with the
observation at 28 minutes of R ~ 19.4 (Xin, et al., 2009, GCN Circ.
9431) implies either that this afterglow is unusually red, or that it
has brightened during the first half hour after the BAT trigger. Such
a long brightening would be highly unusual (Oates, et al., 2009,
MNRAS, 395, 450).
GCN Circular 9431
Subject
GRB 090529: Xinglong TNT optical observation
Date
2009-05-29T15:51:34Z (17 years ago)
From
L.P. Xin at NAOC <xlp@bao.ac.cn>
L.P. Xin, W.K. Zheng, Y. Urata, Y.L. Qiu, J.Y. Wei,
J. Wang, J.S. Deng and J.Y. Hu on behalf of EAFON report:
We have observed GRB 090529 (Sakamoto et al. GCN 9430)
with Xinglong TNT telescope from May 29, 14:36:54 (UT),
24.3 min after the burst. After combined 20*20s white
band images and preliminary analysis, An new source was
found in our combined image within the XRT errorbox.
The brightness is estimated to be about R~19.4 mag
derived from USNO-B1.0 R2 magnitude, at the mean time
of 28 min since the trigger.
The observation is still going.
This message may be cited.
For more information about Xinglong GRBs Follow-up
observations, please visit the website:
http://www.xinglong-naoc.org/grb/
GCN Circular 9430
Subject
GRB 090529: Swift detection of a burst
Date
2009-05-29T14:40:28Z (17 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
T. Sakamoto (NASA/UMBC), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU),
J. R. Cummings (NASA/UMBC), P. A. Evans (U Leicester),
O. Godet (U Leicester), C. Gronwall (PSU), C. Guidorzi (U Ferrara),
S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU),
H. A. Krimm (CRESST/GSFC/USRA), V. Mangano (INAF-IASFPA),
J. Mao (INAF-OAB), R. Margutti (Univ Bicocca&OAB),
C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC),
P. T. O'Brien (U Leicester), J. P. Osborne (U Leicester),
K. L. Page (U Leicester), D. M. Palmer (LANL),
B. Sbarufatti (INAF-IASFPA), M. H. Siegel (PSU) and
T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:
At 14:12:35 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090529 (trigger=353540). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 212.474, +24.437 which is
RA(J2000) = 14h 09m 54s
Dec(J2000) = +24d 26' 13"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve does not show anything
but this is typical for an image trigger.
The XRT began observing the field at 14:15:52.3 UT, 197.1 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source located at RA, Dec 212.46882,
24.45889 which is equivalent to:
RA(J2000) = 14h 09m 52.52s
Dec(J2000) = +24d 27' 32.0"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 80 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 (1.61e+20
cm^-2, Kalberla et al. 2005), with an excess column of 2.9
(+1.72/-1.51) x 10^21 cm^-2 (90% confidence).
The initial flux in the 2.5 s image was 1.48e-09 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 205 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
0.02.
Burst Advocate for this burst is T. Sakamoto (Taka.Sakamoto AT 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.)