GRB 060604
GCN Circular 5212
Subject
GRB 060604: Swift detection of a burst with possible optical counterpart
Date
2006-06-04T18:46:18Z (19 years ago)
From
Jamie A. Kennea at PSU/Swift-XRT <kennea@astro.psu.edu>
M. J. Page (UCL-MSSL), A. J. Blustin (UCL-MSSL),
J. R. Cummings (NASA/ORAU), N. Gehrels (NASA/GSFC),
O. Godet (U Leicester), J. A. Kennea (PSU), K. M. McLean (LANL/UTD),
K. L. Page (U Leicester), G. Sato (GSFC/JSPS/USRA) and
M. Stamatikos (NASA/ORAU) report on behalf of the Swift Team:
At 18:19:00 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 060604 (trigger=213486). Swift slewed immediately to the
burst. The BAT on-board calculated location is
RA,Dec 337.242, -10.905 {22h 28m 58s, -10d 54' 17"} (J2000)
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a single FRED
peak with a duration of about 8 sec. The peak count rate
was ~1000 counts/sec (15-350 keV), at ~3 sec after the trigger.
The XRT began observing the field at 18:20:48 UT, 109 seconds after the
BAT trigger. XRT found a variable, uncatalogued X-ray source
located at RA(J2000) = 22h 28m 54.9s, Dec(J2000) = -10d 55' 03.0", with an
estimated uncertainty of 4.7 arcseconds (90% confidence radius).
During the first 100s of data, the source shows bright flaring activity.
This location is 65 arcseconds from the BAT on-board position, within
the BAT error circle. The initial flux in the 2.5s image was
2.9e-09 erg/cm2/s (0.2-10 keV).
UVOT took a finding chart exposure of 100 seconds with the White
(160-650 nm) filter starting 117 seconds after the BAT trigger. There
is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image
at (RA,DEC) (J2000) of (337.2292,-10.9155) or
(22h28m55.01s,-10o54'55.8") with a 1-sigma error radius of about 0.6
arc sec. This position is 7.2 arc sec. from the center of the XRT
error circle. The estimated magnitude is 18.0 with a 1-sigma error of
about 0.5 mag. No correction has been made for the expected extinction
corresponding to E(B-V) of 0.04.
GCN Circular 5214
Subject
GRB 060604: BAT refined analysis
Date
2006-06-05T01:50:02Z (19 years ago)
From
Jay R. Cummings at NASA/GSFC/Swift <jayc@milkyway.gsfc.nasa.gov>
A. Parsons (GSFC), L. Barbier (GSFC), S. Barthelmy (GSFC),
J. Cummings (GSFC/ORAU), E. Fenimore (LANL), N. Gehrels (GSFC),
D. Hullinger (BYU-Idaho), H. Krimm (GSFC/USRA), M. Koss (GSFC/UMD),
C. Markwardt (GSFC/UMD), D. Palmer (LANL), T. Sakamoto (GSFC/ORAU),
G. Sato (GSFC/JSPS/USRA), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), on behalf of the Swift-BAT team:
Using the data set from T-119.2 to T+182.9 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 060604 (trigger #213486)
(Page, et al., GCN 5212). The BAT ground-calculated position is (RA,Dec)
337.233, -10.937 deg {22h 28m 55.8s, -10d 56' 14.8"} (J2000) +- 2.9 arcmin,
(radius, sys+stat, 90% containment). The partial coding was 72%.
The burst was very weak in BAT. There was some low-level soft emission
over ~25 seconds starting at T-50, followed by the main peak at T+0.
T90 (15-350 keV) is 10 +- 3 sec (estimated error including systematics).
The time-averaged spectrum from T-1.4 to T+8.3 is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.90 +- 0.41. The fluence in the 15-150 keV band is
1.3 +- 0.3 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from
T+2.28 sec in the 15-150 keV band is 0.6 +- 0.1 ph/cm2/sec. All the quoted
errors are at the 90% confidence level.
GCN Circular 5215
Subject
GRB 060604: Swift-XRT Team refined analysis
Date
2006-06-05T07:35:45Z (19 years ago)
From
Kim Page at U.of Leicester <kpa@star.le.ac.uk>
K.L. Page, E. Rol (U. Leicester) and M.J. Page (UCL-MSSL) report on behalf
of the Swift-XRT team:
We have analysed the first 3 orbits of X-ray data obtained for GRB 060604
(BAT trigger 213486). Using 5.1 ks of Photon Counting (PC) mode data, we
find a refined position of:
RA(J2000) = 22 28 54.97
Dec(J2000) = -10 54 59.9
with an uncertainty of 3.7 arcsec (90% containment). This is 3.3 and 4.1
arcsec from the on-board XRT and UVOT positions respectively (GCN 5212;
Page et al.) and 74.6 arcsec from the ground-calculated BAT position given
in GCN 5214 by Parsons et al.
The source was at a high enough count-rate to remain in Windowed Timing
(WT) mode for the whole of the (short) first orbit (117-255 seconds after
the trigger). During this time, the light-curve shows two strong flares,
peaking at ~137 and ~172 seconds after the burst. Underlying these flares
is a steep decay of alpha_1 = 3.07 +/- 0.20. Between the end of the WT
data and the start of the second orbit of (PC) data, there is a break to
a much shallower slope of alpha_2 = 0.48 +/- 0.20.
The WT flares show clear spectral evolution. The later PC data are well
fitted by a single power-law with Gamma = 1.89 +/- 0.14, with no evidence
for excess NH above the Galactic value of 4.57e20 cm^-2. (The 90% upper
limit for any excess is 7e20 cm^-2.)
Assuming the shallow decay contines, at 24 hours the count rate is
predicted to be 0.030 count s^-1, corresponding to an observed
(unabsorbed) flux of 1.40e-12 (1.57e-12) erg cm^-2 s^-1.
This circular is an official product of the Swift-XRT team.
GCN Circular 5216
Subject
GRB 060604 optical photometry
Date
2006-06-05T10:27:29Z (19 years ago)
From
Nial Tanvir at IofA U.Cambridge <nrt@ast.cam.ac.uk>
N. Tanvir (U. of Hertfordshire), E. Rol (U. of Leicester)
and P. Hewett (IoA, Cambridge) report:
We imaged the Swift detected burst GRB 060604 (Page et al. GCN 5212)
with the AUX-port camera on the WHT at June 5.169 UT. A 300s R-band exposure
shows a source at the position of the UVOT counterpart which has apparently
faded, thus confirming the afterglow ID.
By comparison with the two nearby USNO stars, we estimate a magnitude
of R=21.4 with an uncertainty (given the rough calibration) of 0.3 mag.
GCN Circular 5218
Subject
GRB 060604: redshift
Date
2006-06-05T12:24:51Z (19 years ago)
Edited On
2024-11-18T09:54:48Z (7 months ago)
From
Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
A. J. Castro-Tirado, P. Amado (IAA-CSIC Granada),
I. Negueruela (U. de Alicante), J. Gorosabel, M. Jelínek
and A. de Ugarte Postigo (IAA-CSIC),
report:
"We have observed the optical afterglow of GRB 060604 (Page et al.
GCN Circ. 5212) with the 2.5m Nordic Optical telescope (+ALFOSC)
at Observatorio del Roque de los Muchachos (La Palma). Observations
consisted of a 150 s V-band exposure with showed a faint object at
the location of the proposed Swift/UVOT candidate, in agreement with
Tanvir et al. (GCN Circ. 5216), plus a 1200 s exposure spectrum
covering the range 3200-9100 A with the grism#4. Based on the presence
of a strong continuum break around 4475 A which we identify as due to
Ly-alpha, we estimate a redshift of z = 2.68. Further analysis is in
progress"
This message is citeable.
GCN Circular 5219
Subject
GRB060604: Swift/UVOT detections
Date
2006-06-05T14:25:51Z (19 years ago)
From
Alexander Blustin at MSSL-UCL <ajb@mssl.ucl.ac.uk>
A. J. Blustin (UCL-MSSL) and M. J. Page (UCL-MSSL) report on behalf
of the Swift/UVOT team:
The Swift/UVOT began observing the field of GRB060604 at 18:20:39
on 2006-06-04, 100 s after the BAT trigger (Page et al., GCN 5212).
The afterglow candidate at the position reported by Page et al.
(GCN 5212) was detected at greater than 2 sigma significance in the
V, B, U, UVW1 and White filters. Magnitudes and 3-sigma upper limits
from co-added images in the colour filters, and from two single
images in the White filter, are given below. The weak detection in
the UVW1 band is consistent with the tentative redshift of 2.68
reported by Castro-Tirado et al. (GCN 5218).
Filter T_range(s) Exposure(s) Mag/3sig_UL Significance (sigma)
V 100-10165 1127 21.2 +/- 0.6 2.4
B 4086-23420 1956 21.2 +/- 0.2 5.8
U 3881-29206 2705 21.1 +/- 0.2 4.4
UVW1 3677-28601 2900 22.1 +/- 0.4 2.8
UVM2 3472-27694 2139 21.1 (3sig_UL)
UVW2 4496-6061 321 19.8 (3sig_UL)
White 117-217 98 18.3 +/- 0.1 13.4
White 4290-4490 190 20.5 +/- 0.3 3.9
These magnitudes are uncorrected for Galactic extinction
(E(B-V) = 0.043).
GCN Circular 5253
Subject
GRB 060604, optical observations
Date
2006-06-14T18:24:55Z (19 years ago)
From
Peter Garnavich at U of Notre Dame <pgarnavi@nd.edu>
Peter Garnavich and Agata Karska (Notre Dame)
We observed the position of GRB 060604 (Page et al., GCN 5212)
with the Vatican Advanced Technology Telescope and 2KCCD
camera on 2006 June 5.45 UT (16.5 hours after the burst).
Six R-band images, each with an exposure time of 120s, were
combined and a source detected at the Swift/UVOT position.
Using an average of five USNO-B1.0 stars (magR2) to set the
zero-point we estimate the brightness of the afterglow at
R=21.6 +/- 0.2 mag. This is only slightly fainter than
the observation by Tanvir et al. (GCN 5216) six hours earlier
and suggests a slow decay or contamination from the host
galaxy.
This message may be cited.
GCN Circular 5488
Subject
GRB 060604: VLA Observation
Date
2006-08-29T16:59:36Z (19 years ago)
From
Poonam Chandra at U Virginia/NRAO <pc8s@virginia.edu>
P. Chandra (UVA/NRAO) and D. A. Frail (NRAO) report on behalf of
the Caltech-NRAO-Carnegie GRB Collaboration:
"We observed the field centered on the BAT position of the Swift burst GRB
060604 (GCN#5215) using the VLA at a frequency of 8.46 GHz and starting
at 9.27 UT on Aug 21, about 76 days after the burst. There is no
detection of
the GRB with 2-sigma upper limit of 130 microJy.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."