GRB 060502A, GRB 060502
GCN Circular 5195
Subject
GRB 060502A: Optical afterglow observations
Date
2006-06-02T15:06:26Z (20 years ago)
From
Pall Jakobsson at U Hertfordshire <palli@star.herts.ac.uk>
Pall Jakobsson (Univ. of Hertfordshire), Erik Zackrisson,
Janne Holopainen (Tuorla Observatory), Genoveva Micheva
(Stockholm Observatory), Brian L. Jensen, Johan P. U. Fynbo
and Jens Hjorth (DARK, NBI) report:
Using MOSCA on the 2.56-meter Nordic Optical Telescope, we
obtained 3*300 s R-band images of the GRB 060502A field
(La Parola et al., GCN#5047) on May 3.21 (1.08 days post
burst). At the location of the optical afterglow (Pool et al.,
GCN#5068), 0.7 arcsec outside the XRT borders (La Parola et al.,
GCN#5054), we detect a source with R = 22.5. Combined with
the R-band magnitude reported by Hicken & Garnavich (GCN#5070),
this implies a decay slope of alpha = 1.0.
An image of the field is shown at:
http://star-www.herts.ac.uk/~palli/grb060502A/grb060502A.jpg
GCN Circular 5070
Subject
GRB060502A, optical observation
Date
2006-05-03T15:33:17Z (20 years ago)
From
Peter Garnavich at U of Notre Dame <pgarnavi@nd.edu>
M. Hicken (CfA) and P. Garnavich (Notre Dame)
Images of the field around GRB 060502A (La Parola et al., GCN 5047)
were obtained with the FLWO 1.2m telescope and KepCAM beginning
on 2006 May 2.23 (UT). Four R-band exposures of 120 and 180
seconds were combined and the optical afterglow
(Cenko et al., GCN 5048) is detected but is faint.
The mean time of the combined exposures is 2.77 hours after
the burst. Using stars in the USNO-A2.0 for calibration, we
estimate the brightness of the afterglow to be R=20.1 +/- 0.3 mag.
Also using the USNO-A2.0 catalog we estimate the position of
the afterglow to be RA=16:03:42.63 DEC=66:36:03.7 (J2000)
with an error of 0.7" which is consistent with the Swift/UVOT
position (Poole et al., GCN 5068).
GCN Circular 5068
Subject
GRB 060502A: Swift/UVOT source detection
Date
2006-05-03T10:35:52Z (20 years ago)
From
Tracey Poole at MSSL <tsp@mssl.ucl.ac.uk>
T. S. Poole (UCL-MSSL), and V. La Parola (INAF-IASFPA) on behalf of the
Swift/UVOT team.
The Swift/UVOT began observing the field of GRB060502 (BAT
Trigger=208169, V. La Parola, et. al, GCN 5047) at 03:04:56 UT, 84s
after the BAT trigger.
We detect a fading source with a calculated position of RA = 16:03:42.48
and Dec = +66:36:02.5 (J2000) in the V, B and White filters, and the
summed UVW1 filter. The error in the coordinates of the UVOT source is
+/- 0.56 arcsec (90% confidence). The position is 4.4 arcseconds from
the centre of the XRT error circle reported by V. La Parola, et. al,
(GCN 5054). Checks against the Digitized Sky Survey images yield no
known source at this position on the sky.
The calculated magnitudes of the first afterglow observations in the
UVOT filters are given below. The limiting magnitudes are given to a 3
sigma limit. These values are not corrected for Galactic extinction;
E(B-V) = 0.033.
Filter T_range(s) T_exp(s) Magnitude Comments
V 190-536 346 18.70 +/- 0.14 - source detection
V 5092-5292 200 20.19 - 3 sigma upper limit
B 4478-4678 200 20.04 +/- 0.16 - source detection
B 5910-6110 200 20.91 +/- 0.34 - source detection
U 4273-4473 200 20.84 - 3 sigma upper limit
U 5706-5905 200 20.78 - 3 sigma upper limit
UVW1 4069-4269 200 20.63 - 3 sigma upper limit
UVW1 5501-5701 200 20.61 - 3 sigma upper limit
UVW1 4069-5701 400 20.89 +/- 0.40 - source detection
UVM2 3864-4064 200 20.85 - 3 sigma upper limit
UVM2 5296-5496 200 21.03 - 3 sigma upper limit
UVW2 4888-5087 200 21.60 - 3 sigma upper limit
WHITE 84-184 100 18.50 +/- 0.07 - source detection
WHITE 4682-4882 200 20.53 +/- 0.20 - source detection
WHITE 6115-6314 200 21.22 - 3 sigma upper limit
Where T_range is time post-trigger, and T_exp is the exposure time of
the observation. A 6 arcsec radius was used for all filters.
When summing the two UVW1 200s exposures we see a source detection above
3 sigma. This give a z upper limit of 1.9.
This message may be cited.
GCN Circular 5060
Subject
GRB 060502A: TTT Observations
Date
2006-05-02T22:44:08Z (20 years ago)
From
Melissa Nysewander at UNC,Chapel Hill <mnysewan@astro.unc.edu>
M. Nysewander, J. Harvey, A. Foster, D. Reichart, J. A. Crain, K. Ivarsen
report on behalf of the UNC team of the FUN GRB Collaboration:
Under the automated control of SkyNet, the 0.37-m TTT telescope, located
outside of Fort Collins, Colorado, began observing the localization of GRB
060502A (Parola et al., GCN 5047) 65 seconds after the initial
notification, and 17.8 minutes after the time of the burst in the V & Red
filters.
In our first 160-s exposure at a mean time of 19.1 minutes after the burst,
we do not see the afterglow (Parola et al. GCN 5047, Cenko et al., 5048)
down to a 3-sigma limiting magnitude of R ~ 17.5.
GCN Circular 5054
Subject
GRB060502: Swift-XRT refined analysis
Date
2006-05-02T15:17:44Z (20 years ago)
From
Eleonora Troja at INAF-IASFPA <nora@ifc.inaf.it>
V. La Parola, E. Troja, V. Mangano (INAF-IASFPA), S.
Campana (INAF-OAB), K. L. Page (U Leicester), J. Kennea,
D.N. Burrows (PSU), on behalf of the Swift-XRT team.
We have analyzed the first two orbit of data of GRB060502
(La Parola et al 2006, GCN 5047).
The XRT data set consists of 71 s exposure in Windowed
Timing (WT) mode followed by 355 s exposure in Photon
Counting (PC) mode in the first orbit and 2.4 ks in the
second orbit.
The refined position of the source is
RA (2000) = 16h 03m 42.9s
Dec (2000) = 66�� 35' 58.1"
with an uncertainty of 3.7 arcsec (90% confinement).
This position is only 1 arcsec from the one calculated
from early downlinked data (La Parola et al 2006, GCN 5047),
5.1 arcsec from the UVOT afterglow position and 17.6" from
the BAT refined position (Parsons et al. GCN5053).
The 0.2-10 keV X-ray light curve shows an initial
fast decay with slope -2.87 +/- 0.11 and a break at 252
+/- 17 s from the trigger followed by a second decay slope
of -0.54 +/- 0.05.
The WT spectrum (collected during the pre-break phase)
can be fitted with a power law (photon index 2.3 +/-0.5)
plus a soft thermal component (which can be modelled with
a blackbody at 0.13+/-0.02 keV), with intrinsic absorption
(0.45+/-0.15)e22 cm-2, assuming a redshift of 1.51
(Cucchiara et al. GCN5052).
The PC spectrum after the break is fitted with an absorbed
power law with photon index 1.99 +/-0.15 and intrinsic absorption
(0.6+/-0.2)e22 cm-2.
The Galactic absorption is 2.97e20 cm-2.
With the present decay slope, the 0.2-10 keV flux at 24h
after the trigger is expected to be ~2e-12 erg/s/cm-2
This Circular is an official product of the Swift XRT
Team.
GCN Circular 5053
Subject
GRB 060502: Swift-BAT refined analysis
Date
2006-05-02T13:50:00Z (20 years ago)
From
Takanori Sakamoto at NASA/GSFC <takanori@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 (UMD),
C. Markwardt (GSFC/UMD), D. Palmer (LANL), T. Sakamoto (GSFC/ORAU),
G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC),
on behalf of the Swift-BAT team:
Using the data set from T-119 to T+229 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 060502 (trigger #208169)
(La Parola, et al., GCN 5047). The BAT ground-calculated position is
(RA,Dec) = 240.941, 66.600 deg {16h 3m 45.8s, 66d 35' 59.5"} (J2000)
+- 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 49%.
The mask-weighted lightcurve shows a main peak starting at T-5 sec and
ending at T+30 sec. The second weak peak follows in a duration of ~15 sec.
T90 (15-350 keV) is 33 +- 5 sec (estimated error including systematics).
The time-averaged spectrum from T-5.8 to T+42.0 is best fit by
a simple power-law model. The power law index of the time-averaged spectrum
is 1.43 +- 0.08. The fluence in the 15-150 keV band is 2.2 +- 0.1 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T-0.10 sec in the 15-150 keV
band is 1.7 +- 0.2 ph/cm2/sec.
Eiso is 5.8e+49 ergs (16.5 - 164.9 keV in the GRB rest frame) and
1.5e+52 ergs (37.7 - 376.5 keV in the GRB rest frame) using
z = 0.099 (Chen et al. GCN 5051) and z = 1.51 (Cucchiara et al. GCN 5052)
respectively.
All the quoted errors are at the 90% confidence level.
GCN Circular 5052
Subject
GRB060502: Gemini spectroscopy
Date
2006-05-02T10:13:13Z (20 years ago)
From
Antonino Cucchiara at PSU <cucchiara@astro.psu.edu>
A. Cucchiara (Penn State), P.A. Price (IfA, Hawaii), D.B. Fox, (Penn
State), S.B. Cenko (SRL, Caltech) and B.P. Schmidt (RSAA, ANU) report on
behalf of a larger collaboration:
We have observed the optical afterglow of GRB 060502 (La Parola et al.,
GCN 5047, Cenko et al., 5048)
with the GMOS instrument on Gemini North telescope. Observations
consisted of 2 x
1800 sec exposures with the R400 grating, commencing at 2006 May 2.34
UTC. In the summed spectrum, we identify an absorption system
consisting of Fe II, Mg II and Mg I at a redshift of z ~ 1.51. No other
absorption or emission line systems are apparent.
We acknowledge the rapid response effort of Gemini personnel that
yielded these data.
GCN Circular 5051
Subject
GRB 060502: APO Spectroscopic Observations
Date
2006-05-02T10:12:43Z (20 years ago)
From
Hsiao-Wen Chen at U Chicago <hchen@oddjob.uchicago.edu>
H.-W. Chen (U Chicago), R. McMillan (APO), A. Bender (U Colorado), D.
York, and D. Lamb (U Chicago) report on behalf of a larger collaboration:
"We observed the afterglow of GRB060502A reported by La Parola et al. (GCN
5047) and confirmed by Cenko et al. (GCN5048), using the Dual Imaging
Spectrograph (DIS) with a 1.5-arcsec slit on the 3.5 m telescope at the
Apache Point Observatory. The observations started at UT 05:52:33 on
May 2, 2006, ~ 2.8 hours after the inital Swift/BAT trigger, and were
carried out under a mean seeing condition of 1.3 arcsec in a sequence of
two 1800-sec exposures. The final stacked spectrum covers the spectral
range from 3800 Ang to 8500 Ang with a spectral resolution of 2.4 Ang per
pixel, and appears to be featureless. The abundant fluxes observed below
4000 Ang and the lack of spectral discontinuity below 4500 Ang indicate
that the GRB originated at redshift z < 2.2. We determine a tentative
redshift for the GRB afterglow at z=0.099 +/0.001 based on the tentative
identifications of CaII H&K absorption features at around 4322 and 4361
Ang.
Further analysis is underway.
This message may be cited."
GCN Circular 5049
Subject
GRB060502: Super-LOTIS Observations
Date
2006-05-02T07:13:21Z (20 years ago)
From
Grant Williams at Steward Observatory <ggwilli@mmto.org>
G. G. Williams (MMTO), and P. A. Milne (Steward Observatory) on behalf of
the Super-LOTIS Collaboration, report:
The robotic 0.6-m Super-LOTIS telescope began observing the error box of
GRB060502 (Swift Trigger 208169, GCNC 5047) at 03:20:46 UT, 1034 seconds
after the burst (17.23 min; 33 seconds after the delayed GCN notice).
Our initial observations include 5 x 10s exposures, 5 x 20s exposures, and
30 x 60s exposures, all in the R-band.
Under thin cirrus we do not detect the Swift afterglow reported by La
Parola et al. and Cenko et al. (GCN 5047 & 5048) in our earliest 60 second
exposure to the following 3-sigma limiting magnitude estimated using
nearby USNO-B1.0 stars:
t_mid obs (UT) exp t (s) t-t_0 (s) Limit
--------------------------------------------------------
03:24:56 60 1284 R > 17.9
Additional observations and analysis, including image stacking, are
ongoing.
GCN Circular 5048
Subject
GRB 060502: P60 Afterglow Confirmation
Date
2006-05-02T04:45:42Z (20 years ago)
From
S. Bradley Cenko at Caltech <cenko@srl.caltech.edu>
S. B. Cenko, E. O. Ofek (Caltech), and D. B. Fox (Penn State) report on
behalf of a larger collaboration:
We have imaged the field of GRB060502 (La Parola et al., GCN 5047) with
the automated Palomar 60-inch telescope. Observations began immediately
following astronomical twilight. The UVOT optical candidate is detected
in individual 60 s R, g, and i' images and is cleary fading. We
therefore confirm this object as the afterglow of GRB060502.
We estimate the magnitude of the afterglow to be R ~ 19.8 approximately
40 minutes after the burst trigger (calculated with reference to several
nearby USNO-B objects).
Observations are continuing.
GCN Circular 5047
Subject
GRB 060502: Swift detection of a burst with an optical counterpart
Date
2006-05-02T03:55:38Z (20 years ago)
From
Scott Barthelmy at NASA/GSFC <Scott@lheamail.gsfc.nasa.gov>
V. La Parola (INAF-IASFPA), S. D. Barthelmy (GSFC),
D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU),
F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL),
P. Romano (INAF-OAB), T. Sakamoto (NASA/ORAU), E. Troja (INAF-IASFPA)
and D. E. Vanden Berk (PSU) report on behalf of the Swift Team:
At 03:03:32 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 060502 (trigger=208169). Swift slewed immediately to the burst.
The BAT on-board calculated location is RA,Dec 240.858, +66.595
{16h 03m 26s, +66d 35' 42"} (J2000) with an uncertainty of 3 arcmin
(radius, 90% containment, including systematic uncertainty). The BAT light
curve shows a roughly triangular shaped single peak starting at ~T-8 sec
and lasting until ~T+20 sec. The peak count rate was ~2500 counts/sec
(15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 03:04:48 UT, 76 seconds after the
BAT trigger. Ground analysis of the initial XRT data found a bright,
uncatalogued, fading X-ray source located at RA(J2000) = 16h 03m
42.9s, Dec(J2000) = +66d 35' 57.4", with an estimated uncertainty of
3.9 arcseconds (90% confidence radius). This location is 98
arcseconds from the BAT on-board position, within the BAT error
circle. The initial flux in the 2.5s image was 1.3e-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 85 seconds after the BAT trigger. There
is an 18.4 magnitude source that is not visible in the Digitized Sky
Survey images, at J2000 coordinate 16h 03m 42.48s, +66d 36' 02.5"
(240.9270, +66.6007). The position is 5.7 arcseconds from the center
of the XRT error circle.
This burst triggered BAT at the beginning of a Malindi telemetry
downlink session and so the downlink of the TDRSS notices was delayed
until the end of the pass (~18 min).