GRB 090102
GCN Circular 8856
Subject
GRB 090102: HST observations and host galaxy
Date
2009-01-27T22:33:21Z (17 years ago)
From
Nial Tanvir at IofA U.Cambridge <nrt@ast.cam.ac.uk>
A.J. Levan (Warwick), D. Malesani (DARK/NBI), N.R. Tanvir (Leicester),
A. Fruchter (STScI), J.P.U. Fynbo (DARK/NBI), J. Hjorth (DARK/NBI),
A. de Ugarte Postigo (ESO), P. Curran (MSSL), J. Graham (STScI),
K. Wiersema (U. Leicester) report:
We observed the afterglow of GRB 090102 (Mangano et al. GCN 8762;
Klotz et al. GCN 8761) using the Hubble Space Telescope and Wide Field
Planetary Camera on the 26th Jan 2009. Observations were obtained over
3 orbits (6400s), using the F606W filter. At the location of GRB 090102
we find an obvious host galaxy underlying the GRB afterglow. The magnitude
of the combined afterglow+ host at this time is R~24.5 (AB).
Astrometry utilizing early images obtained at the NOT (de Ugarte Postigo
et al GCN 8766) shows that the location of GRB 090102 is consistent with
the centroid of the galaxy/afterglow combined light (offset = 0.09 +/-
0.06"). This suggests that the afterglow may still be contributing
significantly at the current epoch. Estimates of the magnitude of any
likely point source coincident with this are inevitably uncertain, but do
allow for a continued decay with temporal index alpha~1. Later time
observations are planned, and will allow an accurate subtraction of the
host galaxy light.
Images can be found at
http://www.star.le.ac.uk/~anl/090102
GCN Circular 8816
Subject
GRB090102: MAGIC telescope GeV observation
Date
2009-01-16T12:16:42Z (17 years ago)
From
Markus Garczarczyk at MPI/MAGIC <garcz@mppmu.mpg.de>
Gaug M. (IAC Tenerife), Antonelli L. A. (INAF Rome),
Bastieri D. (Univ. Padova), Becerra J. G. (IAC Tenerife),
Carosi A. (INAF Rome), Covino S. (INAF Rome), Galante N. (MPI Munich),
Garczarczyk M. (IFAE Barcelona), La Barbera A. (INAF Palermo),
Longo F. (INFN Trieste), Persic M. (Univ. Udine), Scapin V. (Univ. Udine),
and Teshima M. (MPI Munich) for the MAGIC collaboration
The MAGIC Imaging Atmospheric Cherenkov Telescope performed a follow-up
observation of GRB090102 (Mangano et al., circular 8762). We started data
taking with MAGIC at 03:14:52 UT under excellent observation conditions.
The observation continued for 13149 s.
No evidence for VHE gamma-ray emission above a (preliminary) analysis
threshold of 89 GeV was found.
A preliminary analysis, for the hypothesis of steady emission and
assumption of a differential photon spectral index of -2.5, yields the
following 95% CL differential flux upper limits, including a 30%
systematic uncertainty on the telescope efficiency. (Because of the
changing telescope sensitivities due to different zenith angle ranges
during the observation of GRB090102, the data sample was split into
5 parts):
E ( 80- 125 GeV): 2.30 * 10^-10 erg/cm^2/s
E ( 125- 175 GeV): 1.61 * 10^-10 erg/cm^2/s
E ( 175- 300 GeV): 0.34 * 10^-10 erg/cm^2/s
E ( 300-1000 GeV): 0.04 * 10^-10 erg/cm^2/s
for a time window from 03:14:01 UT to 04:21:01 UT
E ( 80- 125 GeV): 1.12 * 10^-10 erg/cm^2/s
E ( 125- 175 GeV): 0.50 * 10^-10 erg/cm^2/s
E ( 175- 300 GeV): 0.20 * 10^-10 erg/cm^2/s
E ( 300-1000 GeV): 0.07 * 10^-10 erg/cm^2/s
for a time window from 04:21:01 UT to 05:31:00 UT
E ( 125- 175 GeV): 1.02 * 10^-10 erg/cm^2/s
E ( 175- 300 GeV): 0.30 * 10^-10 erg/cm^2/s
E ( 300-1000 GeV): 0.20 * 10^-10 erg/cm^2/s
for a time window from 05:39:00 UT to 06:02:00 UT
E ( 125- 175 GeV): 2.40 * 10^-10 erg/cm^2/s
E ( 175- 300 GeV): 0.49 * 10^-10 erg/cm^2/s
E ( 300-1000 GeV): 0.25 * 10^-10 erg/cm^2/s
for a time window from 06:02:00 UT to 06:25:00 UT
E ( 175- 300 GeV): 0.40 * 10^-10 erg/cm^2/s
E ( 300-1000 GeV): 0.11 * 10^-10 erg/cm^2/s
for a time window from 06:25:00 UT to 07:02:00 UT
We can also exclude emission of a constant flux in any 100s time bin
smaller than:
E ( 80- 125 GeV): 12.58 * 10^-10 erg/cm^2/s
E ( 125- 175 GeV): 7.53 * 10^-10 erg/cm^2/s
E ( 175- 300 GeV): 3.27 * 10^-10 erg/cm^2/s
E ( 300-1000 GeV): 1.41 * 10^-10 erg/cm^2/s
for a time window from 03:14:01 UT to 04:21:01 UT
E ( 80- 125 GeV): 18.16 * 10^-10 erg/cm^2/s
E ( 125- 175 GeV): 15.56 * 10^-10 erg/cm^2/s
E ( 175- 300 GeV): 3.46 * 10^-10 erg/cm^2/s
E ( 300-1000 GeV): 1.40 * 10^-10 erg/cm^2/s
for a time window from 04:21:01 UT to 05:31:00 UT
E ( 125- 175 GeV): 11.61 * 10^-10 erg/cm^2/s
E ( 175- 300 GeV): 2.47 * 10^-10 erg/cm^2/s
E ( 300-1000 GeV): 0.91 * 10^-10 erg/cm^2/s
for a time window from 05:39:00 UT to 06:02:00 UT
E ( 125- 175 GeV): 12.38 * 10^-10 erg/cm^2/s
E ( 175- 300 GeV): 5.38 * 10^-10 erg/cm^2/s
E ( 300-1000 GeV): 1.53 * 10^-10 erg/cm^2/s
for a time window from 06:02:00 UT to 06:25:00 UT
E ( 175- 300 GeV): 10.06 * 10^-10 erg/cm^2/s
E ( 300-1000 GeV): 1.28 * 10^-10 erg/cm^2/s
for a time window from 06:25:00 UT to 07:02:00 UT
Further analysis, exploiting the recently upgraded event trigger, is still
underway for energies below 80 GeV.
This message can be cited.
GCN Circular 8792
Subject
GRB 090102: WSRT Radio Observations
Date
2009-01-09T16:39:06Z (17 years ago)
From
Alexander van der Horst at NASA/MSFC <Alexander.J.VanDerHorst@nasa.gov>
A.J. van der Horst (NASA/MSFC/ORAU), R.A.M.J. Wijers and A.P. Kamble
(University of Amsterdam) report on behalf of a larger collaboration:
"We observed the position of the GRB 090102 afterglow at 4.9 GHz with the
Westerbork Synthesis Radio Telescope at January 8 18.88 UT to January 9
6.86 UT, i.e. 6.66 - 7.16 days after the burst (GCN 8762).
We do not detect a radio source at the position of the optical counterpart
(GCN 8766). The three-sigma rms noise in the map around that position is
72 microJy per beam. The formal flux measurement for a point source at the
position of the optical counterpart is 12 +/- 24 microJy.
We would like to thank the WSRT staff for scheduling and obtaining these
observations."
GCN Circular 8780
Subject
GRB 090102: optical decay
Date
2009-01-05T12:15:18Z (17 years ago)
From
Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <malesani@astro.ku.dk>
D. Malesani, J. P. U. Fynbo (DARK/NBI), A. de Ugarte Postigo (ESO), J.
Gorosabel (IAA/CSIC), S. Barros, E. Simpson (QUB), report on behalf of a
larger collaboration:
We observed the afterglow of GRB 090102 (Mangano et al., GCN 8762; Klotz
et al., GCN 8761) with the Nordic Optical Telescope equipped with
ALFOSC, at several epochs. The decay in the R band is consistent with a
single power law with slope alpha ~ 0.9 between 0.1 and 3 days after the
GRB. This is in agreement with the early-time slopes reported by Afonso
et al. (GCN 8771) and Cenko et al. (GCN 8773). There is marginal
indication that the light curve may flatten at late times, which could
be due to the presence of a host galaxy. Further observations are
encouraged.
A plot with the light curve, including data from GROND (GCN 8771), P60
(GCN 8773), and IAC80 (de Ugarte Postigo et al., GCN 8772) is posted at
the following URL:
http://www.astro.ku.dk/~malesani/GRB/090102/lc.png
[GCN OPS NOTE(05jan09): Per author's request, the Klotz reference
was changed from 8762 to 8761.]
GCN Circular 8779
Subject
VLA radio upper limit on GRB 090102
Date
2009-01-04T19:25:06Z (17 years ago)
From
Poonam Chandra at U Virginia/NRAO <pc8s@virginia.edu>
Poonam Chandra (RMC) and Dale A. Frail (NRAO) report on
behalf of the Caltech-NRAO-Carnegie GRB Collaboration:
"We used the Very Large Array to observe the field of view toward
GRB 090102 (GCN 8762) at a frequency of 8.46 GHz on 2009 Jan 03.35
UT. The GRB radio afterglow is undetected at 3-sigma level. The
flux density at the Swift UVOT afterglow position (GCB 8762) is
91 +/- 49 uJy.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."
GCN Circular 8778
Subject
GRB 090102: GRT Optical Observation
Date
2009-01-04T17:13:41Z (17 years ago)
From
Takanori Sakamoto at NASA/GSFC <takanori.sakamoto-1@nasa.gov>
T. Sakamoto (UMBC/GSFC), D. Donato (ORAU/GSFC), N. Gehrels (GSFC),
T. Okajima (JHU/GSFC), T. N. Ukwatta (GWU/GSFC), Y. Urata (Saitama U),
C. Wallace (FGCU)
We observed the field of GRB 090102 detected by Swift (trigger #338895;
Mangano et al., GCN #8762) with the 14-inch Goddard Robotic Telescope (GRT)
located at the Goddard Geophysical and Astronomical Observatory
(http://cddisa.gsfc.nasa.gov/ggao/).
Ten set of 5 sec and five set of 10 sec and 30 sec exposures were taken in
the R filter starting from Jan. 2 03:11:58 (UT) about 16.2 min after
the trigger. We do not detect the optical afterglow (Klotz et al.,
GCN #8761, Mangano et al., GCN #8762) both in the individual
images and the combined image. The estimated three sigma upper limit
of the combined image (total exposure of 250 sec) is ~17.9 mag using
the USNO-B1 catalog.
GCN Circular 8776
Subject
Konus-Wind observation of GRB 090102
Date
2009-01-03T12:32:25Z (17 years ago)
From
Valentin Pal'shin at Ioffe Inst <val@mail.ioffe.ru>
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P.
Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind
team, report:
The long GRB 090102 (Swift-BAT trigger #338895: Mangano et al., GCN
8762; Sakamoto et al., GCN 8769) triggered Konus-Wind at T0=10536.283 s
UT (02:55:36.283).
The burst light curve shows a multipeaked structure with a duration of
~30 s.
As observed by Konus-Wind the burst
had a fluence of 3.09(-0.25, +0.29)x10^-5 erg/cm2,
and a 256-ms peak flux measured from T0+12.016 s
of 5.10(-0.72, +0.74)x10^-6 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).
The time-integrated spectrum of the burst
(from T0 to T0+33.024 s) can be fitted (in the 20 keV - 2 MeV
range) by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.86(-0.13, +0.14),
and Ep = 451(-58, 73) keV (chi2 = 48.8/65 dof).
Fitting by GRB (Band) model yields the same alpha and Ep,
and only an upper limit on the high energy
photon index: beta < -2.73 (chi2 = 68.8/64 dof).
All the quoted errors are at the 90% confidence level.
Assuming z = 1.547 (de Ugarte Postigo et al., GCN 8766)
and a standard cosmology model with H_0 = 70 km/s/Mpc, Omega_M = 0.27,
Omega_\Lambda = 0.73, the isotropic energy release E_iso ~1.9x10^53 erg,
the peak luminosity (L_iso)_max ~ 7.8x10^52 erg/s, and Ep_rest ~1100keV.
The Konus-Wind light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB090102_T10536/
GCN Circular 8774
Subject
GRB 090102: Hobby-Eberly Telescope Spectroscopy
Date
2009-01-03T07:13:58Z (17 years ago)
From
Antonino Cucchiara at PSU <cucchiara@astro.psu.edu>
A. Cucchiara and D. B. Fox (Penn State) report:
"Starting on 2009 January 2.24 UT we used the Marcario LRS spectrograph
on the Hobby-Eberly Telescope (R ~ 230) to obtain a 1000s spectrum of
the optical afterglow of GRB 090102 (Mangano et al., GCN 8762, Covino
et al., GCN 8763).
The spectrum covers the wavelength range 4200 to 10,000 Angstrom.
Unfortunately the data were taken under bad seeing conditions and the
average S/N is ~5.
Based on a preliminary calibration we detect some absorption features which
we identify as the MgII doublet (2796,2803) and MgI(2856) at redshift z
= 1.55.
This value is consistent with the redshift reported by de Ugarte Postigo
et al.
(GCN 8766) and Cenko et al. (GCN 8773).
We thank the HET staff for performing this observation, in particular
John Caldwell."
GCN Circular 8773
Subject
GRB 090102: P60 Imaging and P200 Spectroscopy
Date
2009-01-03T01:55:08Z (17 years ago)
From
S. Bradley Cenko at Caltech <cenko@srl.caltech.edu>
S. B. Cenko (UC Berkeley), A. Rau and M. Salvato (Caltech) report on
behalf of a larger collaboration:
We have imaged the field of GRB090102 (Mangano et al., GCN 8762) with the
automated Palomar 60-inch telescope beginning at 03:46 on 2 Jan 2008 UT (~
50 min after the burst). Observations were taken in the R, i', and g'
filters and continued throughout the night until sunrise roughly 10 hours
later.
The optical afterglow (Klotz et al., GCN 8761, Covino et al., GCN 8763) is
well detected in all three filters. All three bands exhibit a relatively
smooth power-law decay with index ~ 0.9, consistent with the value
reported by Afonso et al. (GCN 8771). We report here the following subset
of our R-band observations:
Tmid (s) Texp (s) Mag Err
--------------------------------------
3190.2 120.0 19.75 0.13
5266.2 120.0 20.02 0.06
7704.3 120.0 20.41 0.07
9973.9 120.0 20.56 0.07
11911.5 120.0 20.78 0.08
14068.6 120.0 21.01 0.09
16144.7 120.0 21.09 0.09
18522.6 600.0 21.23 0.06
20631.5 600.0 21.42 0.06
22756.7 600.0 21.58 0.07
24832.6 600.0 21.86 0.08
27994.7 1200.0 21.72 0.05
32188.5 1200.0 22.02 0.06
36411.3 1200.0 21.93 0.11
Photometric calibration was performed relative to the SDSS DR7, with
photometric transformations from Jordi, Grebel, & Ammons (A&A, 460, 2006).
In addition, we have obtained a single 1800 s spectrum of the afterglow
with the Double Beam Spectrograph mounted on the Palomar 200" Hale
telescope at a mean epoch of Jan 2.22. The spectrograph was configured to
provide wavelength coverage from the atmospheric cutoff to ~ 8000 A. We
confirm the results of de Ugarte Postigo (GCN 8766), finding a single
strong absorption system at z = 1.546. Given the lack of strong
Ly-alpha absorption, we place a slightly stricter limit on the host
redshift of z < 1.9.
GCN Circular 8772
Subject
GRB 090102 Observations from IAC80
Date
2009-01-03T01:31:48Z (17 years ago)
From
Antonio Deugarte at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (ESO), L. Blanco (IAC)
A.J. Castro-Tirado (IAA-CSIC), report on behalf
of a larger collaboration:
We have observed the field of GRB090102 (Mangano et al.,
GCN 8762) from the IAC80 telescope at Iza�a Observatory in
Tenerife (Spain). A 6x300s combined exposure with mean
epoch 2.92 Jan 2009 (19.2h after the burst) shows the afterglow
(Klotz et al., GCN 8761) with R=22.6+/-0.3, as compared to
stars of the UNSO-B1.0. This is consistent with the prediction
of Afonso et al. (GCN 8771) for day 1.
GCN Circular 8771
Subject
GRB 090102: GROND observations of the optical afterglow
Date
2009-01-02T23:59:05Z (17 years ago)
From
Paulo M. J. Afonso at MPE <pafonso@mpe.mpg.de>
GRB 090102: GROND observations of the optical afterglow
P. Afonso, T. Kruehler (both MPE Garching), S. Klose (TLS Tautenburg), and
J. Greiner (MPE Garching) report on behalf of the GROND team:
GROND (Greiner et al. 2008, PASP 120, 405), mounted at the 2.2m ESO/MPI
telescope at La Silla Observatory (Chile),started observations of the field
of GRB 090102 (Mangano et al. 2008, GCN #8762) in g'r'i'z'JHK at 05:25 UTC,
2.50 h after the burst.
Preliminary photometry yields the following r' band magnitudes of the
optical afterglow (Klotz et al., GCN #8761, and also GCNs #8762, #8763,
#8764, #8766 and #8770), calibrated against SDSS field stars.
T_mid[s] Exp[s] AB Mag MagErr
-------------------------------
9042 66 20.58 0.05
9158 66 20.59 0.04
9265 66 20.58 0.03
9373 66 20.59 0.06
9515 115 20.59 0.04
9711 115 20.65 0.02
9903 115 20.67 0.02
10091 115 20.66 0.03
10423 375 20.70 0.02
10868 375 20.78 0.02
11320 375 20.79 0.02
11780 375 20.86 0.02
The quoted error is statistical only. There is an additional systematic
error in the absolute calibration using SDSS field stars which is expected
to be in the 0.05 mag range.
In this time interval, the light curve is well described with a single power
law of index 1.0 +/- 0.1, compatible with the value reported by Curran et
al. (GCN #8770). Comparing against the early TAROT data (Klotz et al., GCN
#8764), this indicates a flattening of the light curve. If the afterglow
continues to decline with this power law, we predict r' band magnitudes of
~23.1 at 1 day and ~24.3 at 3 days after the burst.
After correcting for a Galactic foreground extinction corresponding to a
reddening of E_(B-V)=0.05 (Schlegel et al. 1998), the g' to K band SED is
well described with a power law of spectral index beta = 1.0 +- 0.2.
GCN Circular 8770
Subject
Swift UVOT observations of GRB 090102
Date
2009-01-02T17:15:34Z (17 years ago)
From
Peter Curran at MSSL <pac@mssl.ucl.ac.uk>
P.A. Curran (UCL-MSSL), V. Mangano (INAF-IASF PA) and S.T. Holland
(GSFC) on behalf of the Swift/UVOT team.
The Swift Ultra-Violet/Optical Telescope (UVOT) began settled
observations of the Swift localised GRB 090102 (#338895; Mangano et al.,
GCN 8762) ~400 seconds after the BAT trigger.
An afterglow, consistent with the enhanced XRT position (Beardmore et
al., GCN 8765) and with the afterglow candidate of Klotz et al. (GCN
8761), is detected at the position reported by Mangano et al. (GCN
8762). The source is detected in the initial optical observations but
quickly fades (with alpha ~ 0.9 +/- 0.2 in white filter) below detection
limits. The initial magnitudes (or 3 sigma limits) are:
Filter t_mid(s) Exp(s) Mag
wh 470. 147. 18.04 +/- 0.04
v 382. 10. 17.02 +/- 0.29
b 660. 19. 18.35 +/- 0.27
u 635. 19. 17.89 +/- 0.26
uvw1 3547. 255. >19.99
uvm2 6278. 197. >19.67
uvw2 1035. 388. >20.45
The detection in u along with the limits in uvw1 and bluer is consistent
with a redshift of approximately ~1.8 < z < ~2.5 and with the
spectroscopic redshift suggested by de Ugarte Postigo et al. (GCN 8766).
The values quoted above are in the UVOT photometric system (Poole et al.
2008, MNRAS, 383, 627). They are not corrected for the expected
Galactic extinction corresponding to a reddening of E(B-V)=0.047 mag in
the direction of the burst (Schlegel et al. 1998).
GCN Circular 8769
Subject
GRB 090102: Swift-BAT refined analysis
Date
2009-01-02T16:35:19Z (17 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
T. Sakamoto (GSFC/UMBC), 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), V. Mangano (INAF-IASFPA), C. B. Markwardt (GSFC/UMD),
D. M. Palmer (LANL), 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-239 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 090102 (trigger #338895)
(Mangano, et al., GCN Circ. 8762). The BAT ground-calculated position is
RA, Dec = 128.248, 33.107 deg, which is
RA(J2000) = 08h 32m 59.5s
Dec(J2000) = +33d 06' 25.7"
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 6%.
The mask-weighted light curve shows approximately 4 overlapping peaks
starting at ~T-14 sec, peaking at ~T+2 sec, and ending at ~T+15 sec.
T90 (15-350 keV) is 27.0 +- 2.2 sec (estimated error including systematics).
The time-averaged spectrum from T-13.9 to T+18.7 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.36 +- 0.08. The fluence in the 15-150 keV band is 6.8 +- 0.3 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+1.68 sec in the 15-150 keV band
is 5.5 +- 0.8 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/338895/BA/
GCN Circular 8768
Subject
GRB 090102: Swift burst of interest
Date
2009-01-02T16:34:41Z (17 years ago)
From
Vanessa Mangano at INAF-IASFPA <vanessa@ifc.inaf.it>
V. Mangano (INAF-IASF PA), S. Bathelemy (GSFC), P. A. Curran
(UCL-MSSL), N. Gehrels (NASA/GSFC), D. Burrows (PSU)
report on behalf the Swift team:
Based on its bright multiwavelength emission and good sun angle,
the Swift team declares GRB 090102 to be a burst of interest
to be followed by Swift to late time. We encourage ground
based follow-ups and cooperation of the scientific community in
revising Swift observation plans according to results. Please post
your results / plans or send us informal information.
GCN Circular 8767
Subject
GRB 090102: Swift XRT refined analysis
Date
2009-01-02T16:30:08Z (17 years ago)
From
Vanessa Mangano at INAF-IASFPA <vanessa@ifc.inaf.it>
V. Mangano, V. La Parola, B. Sbarufatti (INAF-IASF PA)
report of behalf the Swift XRT team:
We have analysed 6 orbits of Swift XRT data of GRB 090102
(Mangano et al. GCN Circ. 8762), consisting of 241 s in WT mode
and 6.7 ks in PC mode.
The XRT observation started 393 s after the trigger.
The XRT light curve is well fitted by a single power-law
with slope -1.32 +/- 0.01, and if decaying at this rate
the source will reach a count rate level of 0.02 counts/s
after one day.
The WT spectrum is well fitted by an absorbed power-law
with photon index 1.7 +/- 0.1, Galactic NH = 4.0e20 cm^-2
(Kalberla et al. 2005) and intrinsic absorption column of
(3.8 +/- 2.0) e21 cm^-2 at the measured redshift z = 1.547
(De Ugarte Postigo et al. GCN Circ. 8766).
The average observed [unabsorbed] flux during the WT observation
is 6.2e-10 [7.2e-10] erg cm^-2 s^-1.
The PC spectrum, extracted from about T+630 s to T+25 ks,
is also well fitted by an absorbed power law with photon
index 1.8 +/- 0.1, Galactic NH = 4.0e20 cm^-2 and
and intrinsic NH = (7.0 +/- 2.0) e21 cm^-2 at z = 1.547.
The average observed [unabsorbed] flux during the PC observation is
2.8e-11 [3.5e-11] erg cm^-2 s^-1.
The rate to flux conversion factor is 1.3e-10 erg cm^-2 counts^-1.
This is an official product of the Swift XRT team.
GCN Circular 8766
Subject
GRB 090102: NOT redshift
Date
2009-01-02T09:29:37Z (17 years ago)
From
Pall Jakobsson at U Hertfordshire <P.Jakobsson@herts.ac.uk>
Antonio de Ugarte Postigo (ESO), Pall Jakobsson (U. Iceland),
Daniele Malesani, Johan P. U. Fynbo (DARK/NBI), Elaine Simpson
and Susana Barros (Queen's University Belfast) report:
We observed the field of GRB 090102 (Mangano et al., GCN 8762)
with the NOT/ALFOSC starting on Jan 2 at 03:33 (38 minutes after
the burst onset). The optical afterglow detected by Klotz et al.
(GCN 8761) and Mangano et al. is detected with R ~ 19.6 (based on
unfiltered images) at the following coordinates (J2000, 0.5" error):
RA: 08:32:58.54
Dec.: +33:06:51.1
A 45-min low-resolution spectrum was also obained (2 hours post
burst). A firm upper limit of z < 2.1 can be placed on the
redshift of GRB 090102 from the lack of Ly-alpha forest lines in
the spectrum of the afterglow.
The spectrum also displays several metal lines, including Fe II,
Mg II, Mg I, Al II, Al III and C IV, at a redshift of z = 1.547.
No other significant lines are visible. We therefore conclude
that z = 1.547 is the redshift of GRB 090102.
GCN Circular 8765
Subject
GRB 090102: Enhanced Swift-XRT position
Date
2009-01-02T07:31:44Z (17 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1798 s of XRT Photon Counting mode data and 4 UVOT
images for GRB 090102, 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 = 128.2442, +33.1145 which is equivalent
to:
RA (J2000): 08h 32m 58.60s
Dec (J2000): +33d 06' 52.1"
with an uncertainty of 1.7 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
http://www.swift.ac.uk/xrt_positions/Goad.pdf), the current algorithm is an
extension of this method.
This circular was automatically generated, and is an official product of the
Swift-XRT team.
GCN Circular 8764
Subject
GRB 090102: TAROT Calern observatory optical light curve
Date
2009-01-02T05:14:46Z (17 years ago)
From
Alain Klotz at CESR-CNRS <Alain.Klotz@free.fr>
Klotz, A. (CESR-OMP), Gendre, B. (OAMP),
Boer M. (OHP), Atteia J.L. (LATT-OMP) report:
We analyzed images of GRB 090102 detected by SWIFT
(trigger 338895) with the TAROT at the Calern
observatory, France.
In our previous GCN Circ. (9761) we made a mistake
in the celestial coordinates of the optical afterglow.
TAROT position is compatible with UVOT (Mangano et
al. GCNC 8762).
The first image is trailed with a duration of 60.0s
(see the description in Klotz et al., 2006, A&A 451, L39)
and we detect the growth of the optical light curve
that culminates at t0+60s (+/- 3s) with a brightness R=13.4
(i.e. ~40s after the end of the gamma activity).
We calibrated magnitudes in R band using
NOMAD1 1231-0209716 (R=13.31).
After t0+60s, the decay of the afteglow is classic with
a decay of alpha=1.6 +/- 0.2. Hereafter, TAROT Calern
data (tstart and tend are expressed in seconds after
the BAT trigger t0):
tstart tend R dR
40.8 46.8 14.3 0.2
46.8 52.8 13.6 0.1
52.8 58.8 13.4 0.1
58.8 64.8 13.4 0.1
64.8 70.8 13.5 0.1
70.8 76.8 13.7 0.1
76.8 82.8 13.7 0.1
82.8 88.8 14.0 0.1
88.8 94.8 14.1 0.1
94.8 100.8 14.3 0.1
107.6 137.6 14.4 0.2
144.6 174.6 14.9 0.2
181.6 211.6 15.5 0.3
Further observations are in progress
GCN Circular 8763
Subject
GRB 090102: REM observations of a bright afterglow
Date
2009-01-02T03:30:14Z (17 years ago)
From
Stefano Covino at Brera Astronomical Observatory <stefano.covino@gmail.com>
S. Covino, P. D'Avanzo, L.A. Antonelli, D. Malesani, D. Fugazza, L.
Calzoletti, S. Campana, G. Chincarini, M.L. Conciatore, S. Cutini,
V. D'Elia, F. D'Alessio, F. Fiore, P. Goldoni, D. Guetta, C.
Guidorzi, G.L. Israel, E. Maiorano, N. Masetti, A. Melandri, E.J.A.
Meurs, L. Nicastro, E. Palazzi, E. Pian, S. Piranomonte, L. Stella,
G. Stratta, G. Tagliaferri, G. Tosti, V. Testa, S.D. Vergani, F.
Vitali report on behalf of the REM team:
The robotic 60-cm REM telescope located at La Silla (Chile) observed
automatically the field of the GRB 090102 (Mangano et al. GCN8762)
starting about 35s after the burst (26s after the alert). We detect
a bright object in
our first R- and H-band images consistent with the optical
counterpart identified by UVOT (Mangano et al. GCN8762) and TAROT
(Klotz et al. GCN 8761).
The object is approximately R~14.2 (relative to nearby USNO-B1 stars)
and H~12 (relative to nearby 2MASS stars)
at about 1min after the burst.
Further observations are in progress
GCN Circular 8762
Subject
GRB 090102: Swift detection of a burst with an optical counterpart
Date
2009-01-02T03:08:41Z (17 years ago)
From
David Burrows at PSU/Swift <dxb15@psu.edu>
V. Mangano (INAF-IASFPA), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),
N. Gehrels (NASA/GSFC), S. T. Holland (CRESST/USRA/GSFC),
E. A. Hoversten (PSU), J. A. Kennea (PSU),
V. La Parola (INAF-IASFPA), W.B Landsman (GSFC),
C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC) and
B. Sbarufatti (INAF-IASFPA) report on behalf of the Swift Team:
At 02:55:45 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090102 (trigger=338895). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 128.259, +33.092 which is
RA(J2000) = 08h 33m 02s
Dec(J2000) = +33d 05' 29"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a multi-peaked
structure with a duration of about 30 sec starting about 15 sec before
the trigger. The peak count rate was ~7000 counts/sec (15-350 keV),
at ~2 sec after the trigger.
The XRT began observing the field at 03:02:13.1 UT, 387.2 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 128.2423, +33.1142 which is equivalent to:
RA(J2000) = 08h 32m 58.15s
Dec(J2000) = +33d 06' 51.1"
with an uncertainty of 6.1 arcseconds (radius, 90% containment). This
location is 94 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy.
UVOT took a finding chart exposure of nominal 150 seconds with the White filter
starting 395 seconds after the BAT trigger. There is a candidate afterglow in
the list of sources generated on-board at
RA(J2000) = 08:32:58.54 = 128.24391
DEC(J2000) = +33:06:51.2 = 33.11421
with a 90%-confidence error radius of about 1.10 arc sec. This position is 4.8
arc sec. from the center of the XRT error circle. The estimated magnitude is
18.11. No correction has been made for the expected extinction corresponding to
E(B-V) of 0.05.
Burst Advocate for this burst is V. Mangano (vanessa AT ifc.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 Circular 8761
Subject
GRB 090102: TAROT Calern observatory optical observations
Date
2009-01-02T03:08:29Z (17 years ago)
From
Alain Klotz at CESR-CNRS <Alain.Klotz@free.fr>
Klotz, A. (CESR-OMP), Gendre, B. (LAM_OAMP),
Boer M. (OHP), Atteia J.L. (LATT-OMP) report:
We imaged the field of GRB 090102 detected by SWIFT
(trigger 338895) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.
The observations started 40.8s after the GRB trigger
(6.8s after the notice). The elevation of the field decreased from
from 68 degrees above horizon and weather conditions
were good.
We detect a new fading source in the error box given by SWIFT
at the following position (+/- 1 arcsec):
RA(J2000.0) = 08h 32m 38.1s
DEC(J2000.0) +33d 11' 45.3"
OT was R~15.3 at about 100s after GRB.
Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.
N.B. Galactic coordinates are lon=189.8804 lat=+34.6651
and the galactic extinction in R band is 0.1 magnitudes
estimated from D. Schlegel et al. 1998ApJ...500..525S.
This message may be cited.