GRB 060218
GCN Circular 5376
Subject
GRB 060218 / SN 2006aj Nebular Spectrum
Date
2006-08-01T03:39:43Z (19 years ago)
From
Ryan Foley at UC Berkeley <rfoley@astro.berkeley.edu>
Spectroscopic Detection of the Late Nebular Phase of
SN 2006aj (associated with GRB 060218)
R. J. Foley, J. S. Bloom, D. A. Perley, and N. R. Butler
(UC Berkeley) report:
"We obtained 2x600 sec spectra of GRB 060218 / SN 2006aj
(GCN 4775) on 20060726 UT, 153 rest-frame days past the
GRB trigger, with Keck I (+ LRIS). The spectrum shows
prominent nebular emission lines attributed to [O I]
6300, 6364, Na D, and the Ca II IR triplet. The spectrum
resembles the nebular spectrum of GRB 980425 / SN 1998bw
at a similar epoch. With a redshift of z = 0.033
(Mirabal & Halpern, GCN 4792), this is the most distant
GRB-SN with a observed nebular spectrum.
The [O I] line has a velocity width of 10700 km/s, which
is quantitatively similar to SN 1998bw 157 rest-frame
days past the GRB trigger. The line has one strong peak,
with a slight shoulder, attributed to [O I] 6364. There
is no obvious asymmetry in this spectrum, consistent with
the models of Mazzali et al. (2005, Science, 308, 1284).
Further spectroscopic observations are encouraged.
A comparison of our spectrum of GRB 060218 / SN 2006aj to
a spectrum of GRB 980425 / SN 1998bw can be found at
http://astro.berkeley.edu/~rfoley/foley_etal-grb060218.jpg
GCN Circular 5358
Subject
GRB 060218 (SN 2006aj): IR afterglow detection six months after the
Date
2006-07-25T11:53:01Z (19 years ago)
From
Evgeni Semkov at Inst.of Astronomy,Bulgaria <evgeni@skyarchive.org>
E. Semkov (IA, BAS) on behalf of the BAS/CNRS collaboration report:
We observed the afterglow of GRB 060218 (SN 2006aj) six months after the
burst. Observations were made with the 2m RCC telescope at the National
Astronomical Observatory Rozhen (Bulgaria) on July 24 (UT=01h). The
calibration was made using comparison stars from Hicken et al. (GCN
4898) and Modjaz et al. (astro-ph/0603377). Observations were made under
good atmospheric conditions, but through high airmass (>2.5). A standard
Johnson-Cousins set of filters was used.
The optical counterpart was detected at the following magnitudes:
I=19.53 (+/-0.07), R=19.97 (+/-0.09)
This message may be cited.
GCN Circular 4929
Subject
GRB060218, optical observations
Date
2006-03-27T16:57:54Z (20 years ago)
From
Adalberto Piccioni at Astronomy, Bologna U. <adb@piccio.org>
F. Terra, (Second University of Roma "Tor Vergata"), D. Nanni
(INAF/OAR and Second University of Roma "Tor Vergata"), G. Greco,
C. Bartolini, A. Guarnieri, A. Piccioni (Bologna University), R.
Gualandi, A. De Blasi (INAF Bologna) and G. Pizzichini (INAF/IASF
Bologna) report:
We observed the OT of GRB 060218/SN 2006aj (Cusumano et al. GCN 4775)
in the V and R bands with the 152 cm Loiano telescope equipped with
the BFOSC camera system.
Observations were carried out on 2006 Mar 7 and 11 under poor
observing conditions (seeing=2.7-3.2 arcsec).
Using the comparison stars reported by Hicken et al. (GCN 4898), we
find the following magnitudes, in agreement with those given by other
authors, e.g. Sollerman et al., astro-ph/0603495 and Pian et al.,
astro-ph/0603530:
Mean UT.........filter.....Exptime(s)....... magnitude
Mar 07.7506 ......Rc...........300..........17.31+/-0.06
Mar 07.7633.......Rc......... 1200..........17.36+/-0.03
Mar 07.7779.......V...........1200..........17.76+/-0.04
Mar 11.7865.......V............300..........18.15+/-0.08
Mar 11.7962.......V...........1200..........18.11+/-0.06
Mar 11.8123.......Rc..........1200..........17.63+/-0.04
Mar 11.8302.......Rc..........1200..........17.60+/-0.04
One of our images is posted in our public directory from where it
can be retrieved by sftp using:
hostname: ermione.bo.astro.it
username: publicGRB
password: GRB_bo.
GCN Circular 4900
Subject
GRB060218/SN2006aj: optical observations
Date
2006-03-22T00:45:36Z (20 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
D. Sharapov (MAO, and NOT, La Palma), A. Pozanenko (IKI), and M. Ibrahimov
(MAO) on behalf of larger GRB follow up collaboration report:
We have observed GRB060218/SN 2006aj (Cusumano et al. GCN 4775) with
Maidanak 1.5m telescope in BVR on Feb.27, Mar.08, and in BR bands with
NOT/StanCam on Mar.15. The following photometry is based on Modjaz, et. al.
(2006, astro-ph/0603377) calibration and the same reference stars in each
epochs:
Mid time (UT), B, V, R
Feb.27.63 18.08 (.01) 17.40 (.01) 17.21 (.01)
Mar.08.66 18.98 (.02) 17.83 (.02) 17.39 (.01)
Mar.15.86 19.66 (.03) - 17.84 (.02)
Only measurement errors are presented. The photometry is preliminary,
reduction and observations are continuing. Our observations confirm a
maximum of the light curve (Modjaz, et. al. 2006, astro-ph/0603377) between
Feb.27 and Mar.08. It is also evident gradual reddening of the SN.
The message may be cited.
GCN Circular 4899
Subject
GRB 060218/SN 2006aj, LNA optical observation
Date
2006-03-21T00:14:36Z (20 years ago)
From
Antonio Pereyra at IAG-U.Sao Paulo <antonio@astro.iag.usp.br>
A. Pereyra and A. M. Magalh�es (IAG, Univ. of S�o Paulo) report:
We obtained optical imaging of GRB 060218/SN 2006aj (Cusumano et al., GCN 4775) on
2006/March 3.958 (UT) using the IAG-USP 60cm telescope at the Laborat�rio Nacional de
Astrof�sica (LNA), Brazil. The observation was made under poor sky conditions and
through high airmass (>2). A 90-second exposure in the I filter yielded I = (17.06 +/-
0.10) mag. The zero point calibration was obtained using comparison stars in the GRB
field from Hicken et al. (GCN 4898) and Modjaz et al. (astro-ph/0603377).
This message can be cited.
GCN Circular 4898
Subject
GRB060218: Refined photometric calibration of comparison stars
Date
2006-03-20T20:19:10Z (20 years ago)
From
Malcolm Hicken at Harvard/Physics <mhicken@cfa.harvard.edu>
Malcolm Hicken (CFA), Maryam Modjaz (CFA), Peter Challis (CFA), Robert
Kirshner (CFA), Jose Luis Prieto (OSU), Krzystof Stanek (OSU) and Richard
Cool (Arizona) report:
The CFA Supernova Group obtained UBVRr'i' photometry of 9 comparison stars
in the field of GRB060218/SN2006aj on March 4, 2006 UT. Data was taken
using the FLWO 1.2m telescope at Mt. Hopkins, Arizona. We present our
V-band light curve in Modjaz, et. al. (2006), astro-ph/0603377, submitted
to ApJL. A finding chart, coordinates and photometry can be found at the
following website:
http://cfa-www.harvard.edu/oir/Research/supernova/sn2006aj_compstars.html
It should be noted that our V magnitudes are approximately 0.27 mag
fainter than those derived in GCN 4777 by Cool, et. al. at
http://mizar.as.arizona.edu/~grb/public/GRB060218.
There is also an offset in the other bands. In investigating this
photometric offset, Richard Cool has discovered calibration offsets
between the two SDSS photometric reductions of this field indicating
possible non-photometric conditions or other calibration problems in the
SDSS photometry. The problem is being investigated to ensure data with
suspicious photometric quality will be flagged as such in future SDSS GRB
releases.
GCN Circular 4866
Subject
GRB060218: SARA Observations of SN2006aj
Date
2006-03-12T23:37:38Z (20 years ago)
From
Autumn Homewood at Clemson U <ahomewo@clemson.edu>
A.L. Homewood, C.A. Riddle, K.V. Garimella, M.R. Troutman, D.H. Hartmann
(Clemson University) and G.D. Henson (ETSU) report on behalf of the
Clemson GRB Follow-Up Team:
We have imaged the field of GRB060218 (GCN 4775, 4776) beginning
approximately 4 days after the trigger notice with the SARA 0.9-m at Kitt
Peak, under good weather conditions. We obtained 9 300-seconds exposures
in V filter and 7 300-second exposures in B filter. We detect the
supernova in each exposure and have carried out the following data
analysis:
Observations in V began at UT Feb. 22.0923958 and ended at 22.1539931. We
observe magnitudes ranging from V=17.3 to 17.7 +/- 0.2 mag during that
time period.
Similiarly, observations in B began at UT Feb. 22.096088 and ended at
22.1504167. We observed magnitudes ranging from B=18.2 to 18.7 +/-0.2
mag.
These values correspond to single 300-second exposures, and quoted errors
are 1-sigma. Further analyses of observations from additional nights are
in progress.
The Clemson Unversity GRB Response Site may be found at:
http://people.clemson.edu/~kgarime/burst/index.php
The SARA Homepage can be found at:
http://saraobservatory.org
This message may be cited.
GCN Circular 4863
Subject
GRB 060218/SN 2006aj, high resolution spectra
Date
2006-03-12T15:05:08Z (20 years ago)
From
Sylvio Klose at TLS Tautenburg <klose@tls-tautenburg.de>
E. W. Guenther, S. Klose, Thueringer Landessternwarte Tautenburg,
P. Vreeswijk, University of Chile/ESO,
E. Pian, INAF-OA Trieste, and
J. Greiner, MPE Garching, on behalf of the GRACE collaboration
report:
ESO's VLT-Kueyen (UT 2) observed SN 2006aj (GRB 060218) around the
time of maximum light on March 3/4, 2006. Observations were performed
using the Ultraviolet and Visual Echelle Spectrograph (UVES) at a
spectral resolution of 46 000. The signal-to-noise ratio of the
spectrum (2100 sec exposure time) is about 30 per resolution element,
which is sufficient to measure the equivalent width (EW) of the Na I D
lines along the line of sight.
For the Na I D2 component (lambda 5889.95) produced in our Galaxy we
find EW = (0.321 +/- 0.008) Angstrom. Using the empirical relation
between the equivalent width of the 5889.95 line and the interstellar
reddening (Munari & Zwitter A&A 318, 269, 1997), this corresponds to
a Galactic reddening of E(B-V) = (0.127 +/- 0.005) mag. Assuming a
ratio of total-to-selective extinction of R_V = 3.1, we obtain a
Galactic visual extinction along the line of sight of A_V = (0.39 +/-
0.02) mag. This is slightly less than what follows from the COBE
maps (Schlegel, Finkbeiner, & Davis 1998).
In the GRB host galaxy we identify two redshift systems at a
heliocentric velocity of 10008.1 km/s and 10032.3 km/s (Na I D2) with
the following equivalent widths in the observer frame: system I:
EW(D2) = (0.084 +/- 0.008) Angstrom, system II: EW(D2) = (0.072 +/-
0.008) Angstrom. Assuming that the aforementioned empirical relation
is also representative for the interstellar medium in the GRB host
galaxy, and correcting EW for a factor of 1/(1+z) for the host frame, we
arrive at a combined reddening of E(B-V) = (0.042 +/- 0.003) mag. If
again R_V = 3.1, we obtain a host extinction along the line of sight
of A_V = (0.13 +/- 0.01) mag.
We finally note that the tiny error bars should not be overinterpreted.
They just include the measurement errors but not the systematic error
of the method itself, which we cannot quantify.
We thank the ESO staff, in particular Dominique Naef, for performing
the observations and Alain Smette, ESO, for valuable comments.
This message may be quoted.
GCN Circular 4853
Subject
GRB060218: analysis of the XMM-Newton observation
Date
2006-03-06T19:28:13Z (20 years ago)
From
Andrea De Luca at IASF-CNR,Milano <deluca@iasf-milano.inaf.it>
Andrea De Luca (INAF/IASF, Milano) on behalf
of a larger collaboration reports:
We have analyzed the XMM-Newton observation
of the field of GRB060218, discovered by
Swift/BAT on 2006, February 18 at 03:34:30 UT
(GCN4775, Cusumano et al.)
The XMM-Newton observation started on 2006,
February 20 at 17:21:45 UT (~61.8 hours after
the GRB trigger) and lasted for 14 ks.
The observation is affected by a high
particle background, which hampers a detailed
temporal and spectral analysis of the faint X-ray
afterglow.
We report here on data collected by the EPIC/pn camera.
spanning the time range 223.9-234.9 ks after the trigger.
The afterglow of GRB060218 is detected at the
following coordinates:
RA(J2000): 03h 21m 39.63s, Dec(J2000): 16d 52' 03.4"
with an uncertainty of 1.2 arcsec (1sigma),
fully consistent with the coordinates of the
optical (GCN4779, Marshall et al.) and radio
(GCN4828, Soderberg & Frail) afterglow, as well as
with the Swift/XRT position (GCN4786, Cusumano et al.).
Extracting source events from a circle of 10 arcsec
radius (containing ~50% of the total counts) the pn
time-averaged, background-subtracted count rate in the
0.5-8 keV range is of 0.017+/-0.002 cts/s.
No significant fading of the X-ray flux is detected along
the XMM-Newton observation.
The time-integrated X-ray spectrum is well fit
(reduced chi2=0.98, 14 d.o.f.) by a steep power
law absorbed by the Galactic column (NH=1.1e21 cm^-2,
Dickey & Lockman, 1990), with a photon index Gamma=3.3+/-0.6
(90% conf. level for a single parameter).
The observed flux (0.5-10 keV) is of 5.7x10^-14 erg
cm^-2 s^-1, corresponding to an unabsorbed flux of
8.4x10^-14 erg cm^-2 s^-1.
GCN Circular 4847
Subject
GRB 060218: RTT150 optical observations
Date
2006-03-02T19:13:25Z (20 years ago)
From
Rodion Burenin at IKI, Moscow <rodion@hea.iki.rssi.ru>
R. Burenin, A. Mescheryakov, M. Pavlinsky, R. Sunyaev (IKI),
I. Khamitov, Z. Aslan (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.),
I. Bikmaev, N. Sakhibullin (KSU/AST)
report:
We observed GRB 060218/SN 2006aj (Cusumano et al., GCN 4775) with
Russian-Turkish 1.5-m telescope (RTT150, Bakirlitepe, TUBITAK National
Observatory, Turkey) over 3 nights in BVRI. The magnitudes of the object
are:
Time (UT) B V R I
Feb 21.84 18.49 - 17.82 17.53
Feb 22.75 18.20 17.80 17.62 17.40
Feb 25.75 17.98 17.57 17.30 16.89
The photometry is preliminary and is based on our observations of Landolt
stars in these and previous nights.
This message may be cited.
GCN Circular 4846
Subject
GRB060218: Ep,i - Eiso correlation
Date
2006-03-01T16:43:33Z (20 years ago)
From
Cristiano Guidorzi at ARI,Liverpool JMU <crg@astro.livjm.ac.uk>
L. Amati (INAF-IASF Bologna), F. Frontera (Ferrara University and
INAF-IASF Bologna), C. Guidorzi (Liverpool JM University) and E. Montanari
(Ferrara University) report:
"Based on the photon index measured by Swift/BAT (2.5+/-0.1 in 15-150 keV,
Sakamoto et al., GCN #4822) and Swift/XRT during the prompt emission
(1.82+/-0.01 in 0.2-10 keV, Cusumano et al., GCN #4786), it can be inferred
that the intrinsic peak energy Ep,i of GRB060218/SN2006aj (at the suggested
redshift z=0.03) is < 10 keV and lies probably towards the low energy bound of
XRT (i.e. a few keV at most). This information, when combined with the Eiso
(1-10000 keV) value of about (5 - 8)x10^(49) erg, as derived on the basis of
the preliminary BAT and XRT (first orbit) fluxes and spectra, shows that
GRB060218 is likely consistent with the Ep,i - Eiso (Amati) correlation. This
behaviour, if confirmed by more refined analysis, is at odds with that of
GRB980425/SN1998bw and of the other possibly sub-energetic event
GRB031203/SN2003lw, which showed Ep,i and Eiso values completely inconsistent
with the correlation (see e.g. Amati, 2006, astro-ph/0601553 for a discussion).
Given that one of the most popular explanations of the inconsistency of
GRB980425 and GRB031203 with the Ep,i-Eiso correlation is that they were
'normal' GRBs seen at very high off-axis angles (e.g. Yamazaki, Yonetoku &
Nakamura, 2003, ApJ 594 L79 , Ramirez-Ruiz et al., 2005, ApJ, 625 L91), this
evidence shows that GRB060218 may not be an off-axis event, as also
suggested by Nousek et al. (GGN #4805) based on the 'chromatic' behaviour of
afterglow light curves measured by Swift."
This message may be cited.
GCN Circular 4845
Subject
GRB060218: R-band CCD photmetry
Date
2006-02-28T11:19:33Z (20 years ago)
From
Rudolf Novak at N.Copernicus Obs/Czech Rep <exebece@gmail.com>
R. Novak (N. Copernicus Observatory in Brno, Czech Republic),
report:
We have observed filed of GRB060218 (sn 2006aj) for 133 min during night
24./25.2.2006 with the 40cmreflector at N. Copernicus Observatory
equipped with ST-7 CCD (R band
filter) camera. we have detected source as R aprox. 18mag close to the
limit of the combined dframe beacuse of very bad weather conditions (high
altitude clouds, wind). More precise photometry may be available in
future.
This message may be cited.
GCN Circular 4843
Subject
GRB060218/SN 2006aj: optical observation in V
Date
2006-02-28T10:49:31Z (20 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
M. Andreev (Institute of Astronomy), E. Pavlenko (CrAO), A. Pozanenko
(IKI) on behalf of larger GRB follow up collaboration report:
We observed GRB 060218/SN 2006aj (Cusumano et al. GCN 4775) in V-band with
the 60 cm telescope of peak Terskol observatory on Feb. 22 and Feb. 23. A
series of 60 s exposures were taken in both epochs.
Using SDSS pre-burst observations (Cool et al. GCN 4777) we estimate
brightness of the optical afterglow + SN:
Mid time, exp., V mag
(UT) (s)
Feb.22 17:08 147x60 s 18.00 +/- 0.01
Feb.23 18:20 12x60 s 17.82 +/- 0.03
The brightening rate in V between Feb. 22 and Feb. 23 is 0.16m per day.
GCN Circular 4842
Subject
GRB060218/SN 2006aj: optical observation
Date
2006-02-28T10:44:29Z (20 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Pavlenko, Yu. Efimov, A. Shlyapnikov, V.Rumyantsev (CrAO), A.Pozanenko
(IKI) on behalf of a larger collaboration report:
We observed GRB 060218/SN 2006aj (Cusumano et al. GCN 4775) with CrAO Shajn
2.6m telescope on Feb. 23. A series of BVRI 30 s exposures were taken
starting (UT) 19:27.
Using SDSS pre-burst observations (Cool et al. GCN 4777) we estimate
brightness of the optical afterglow + SN in R:
Mid time, exp., R mag
(UT) (s)
Feb.23 19:32 8x30 s 17.40 +/- 0.01
Feb.23 19:58 8x30 s 17.41 +/- 0.01
The values is compatible with the brightening rate ~0.2 per day between Feb.
20 and Feb. 23 reported earlier (Ovaldsen et al, GCN 4818, Pavlenko et al,
GCN 4838).
GCN Circular 4840
Subject
GRB 060218 : GMRT observation [Correction and Improvement]
Date
2006-02-27T16:41:08Z (20 years ago)
From
Atish Kamble at Raman Research Inst <atish@rri.res.in>
Atish Kamble (Raman Research Institute [RRI], Bangalore, India),
C. H. Ishwara Chandra (NCRA, Pune, India) and D. Bhattacharya (RRI)
report on behalf of a larger GRB collaboration :
The date of GMRT observation of GRB 060218 reported in GCN 4832
has a typo. The correct date of observation was 21 Feb 2006 and
not 20 Feb 2006.
Our apologies for the inconvenience it might have caused.
With further analysis of the data (same observation) we could
improve the upper limits on the radio afterglow flux
of GRB 060218. We now put a 3 sigma upper limit of ~ 0.3 mJy.
This messege may be cited.
GCN Circular 4838
Subject
GRB 060218/SN 2006aj: K-380 optical observations
Date
2006-02-27T12:07:53Z (20 years ago)
From
Sergei Guziy at IAA <gss@iaa.es>
Elena Pavlenko(CrAO, Crimea), Alex Shlyapnikov (CrAO,Crimea),
Sergey Guziy (IAA-CSIC, Granada) , on behalf of a larger collaboration,
report:
"We imaged the field of GRB 060218 (Cusumano et al., GCNs 4775, 4781)
with the K-380 Cassegrain telescope of the Crimean Astrophysical
Observatory.
Observations of the afterglow have been carried out on 2006 Feb 20 -
Feb 23.
A series of 2-minute exposures in R(Johnson) band were acquired.
Calibration was
based on the SDSS catalog. On Feb 20 19:18 - 20:00 UT for 20 combined
images,
afterglow has magnitude R = 18.00 +/- 0.06 and displayed the brightening
of 0.15 mag/day.
Further observations are planned."
This message may be cited.
GCN Circular 4837
Subject
GRB 060218/SN 2006aj, SMARTS optical/IR observations
Date
2006-02-26T18:43:22Z (20 years ago)
From
Bethany Cobb at Yale U <cobb@astro.yale.edu>
B. E. Cobb and C. D. Bailyn (Yale), part of the larger SMARTS
consortium, report:
Using the ANDICAM instrument on the 1.3m telescope at CTIO, we
obtained optical/IR imaging of the position of GRB 060218/SN 2006aj
(GCN 4775, Cusumano et al.) over 5 nights. Total summed exposure time
on each night amounted to 36 minutes in I and 30 minutes in J.
The object shows continued brightening over our images. The preliminary
I magnitude of the object on 2006-02-22 is calculated based
on contemporaneous observations of Landolt RU149. The preliminary J
magnitude on the same day is calculated in comparison to 2MASS
stars in the field.
Mid-Exposure
UT Date and Time
2006-02-22 00:35 I = 17.58 +/- 0.05 J = 17.31 +/- 0.05
I mag relative to 1st epoch J mag relative to 1st epoch
2006-02-23 00:27 -0.18 +/- 0.02 -0.11 +/- 0.05
2006-02-24 00:20 -0.29 +/- 0.02 -0.24 +/- 0.05
2006-02-25 00:16 -0.39 +/- 0.02 -0.28 +/- 0.05
2006-02-26 00:18 -0.46 +/- 0.02 -0.38 +/- 0.05
GCN Circular 4834
Subject
GRB 060218/SN 2006aj: ABT observations
Date
2006-02-25T17:40:22Z (20 years ago)
From
Klaas Wiersema at GRACE/U of Amsterdam <kwrsema@science.uva.nl>
K. Wiersema (University of Amsterdam) and F. Nieuwenhout report on
behalf of the AWSV "Metius" ABT collaboration:
"We observed GRB060218/SN 2006aj (Cusumano et al., GCN 4775)
with the amateur 0.25m ABT telescope, from Alkmaar, The Netherlands,
under moderate observing conditions.
Starting from Feb 24 17:58 UT, a series of 1 minute exposures in
V band were acquired, ending at 18:38 UT. 28 exposures were combined.
The object is detected and we measure V = 17.37 +/- 0.21, using
SDSS g' and r' data from Cool et al. (GCN 4777) and the transformation
equations by Smith et al. (2002).
We like to point out the suitability of this supernova for intensive
amateur follow-up.
The ABT telescope is an internet-controlled 0.25m telescope
located in Alkmaar, The Netherlands, built and operated by members of
local amateur astronomy club "Metius".
This detection of GRB060218/SN 2006aj is the first reported
detection of an optical GRB afterglow/SN from Dutch soil.
We acknowledge the assistance of E. Rol and R. Wijers in making the
ABT GRB follow-up program possible."
GCN Circular 4833
Subject
GRB 060218/SN 2006aj: REM optical and near-infrared observations
Date
2006-02-25T16:53:52Z (20 years ago)
From
Daniele Malesani at SISSA-ISAS,Trieste,Italy <malesani@sissa.it>
S. Covino, D. Malesani, E. Molinari, G. Chincarini, F.M. Zerbi, V.
Testa, G. Tosti, F. Vitali, L.A. Antonelli, P. Conconi, G. Cutispoto, G.
Malaspina, L. Nicastro, E. Palazzi, E. Meurs, P. Goldoni, on behalf of
the REM/ROSS team, report:
We imaged the field of GRB 060218 (Cusumano et al., GCNs 4775, 4781)
with the robotic 60-cm REM telescope located at La Silla, Chile.
Observations were performed on 2006 Feb 25 from 00:16 to 00:30 UT under
mediocre conditions just after the La Silla sunset with the R and J
filters. REM is equipped with the REMIR near-infrared camera (10x10
arcmin^2 FoV, JHK filters) and the ROSS optical spectrograph/imager
(10x10 arcmin^2 FoV, VRI filters and AMICI prism).
The optical counterpart (Cusumano et al., GCN 4775; Marshall et al., GCN
4779; Mirabal et al., GCN 4784) was detected in both bands with magnitudes:
R = 17.05 +- 0.17
J = 16.90 +- 0.20
Calibration was based on the SDSS and 2MASS catalogs for the optical and
near-infrared observations, respectively.
This message is citeable.
GCN Circular 4832
Subject
GRB 060218 : Radio upper limits from GMRT
Date
2006-02-25T10:42:05Z (20 years ago)
From
Atish Kamble at Raman Research Inst <atish@rri.res.in>
Atish Kamble (Raman Research Institute [RRI], Bangalore, India),
C. H. Ishwara Chandra (NCRA, Pune, India) and D. Bhattacharya (RRI)
report on behalf of a larger GRB collaboration :
The Giant Meterwave Radio Telescope (GMRT), India observed the field of
GRB 060218 (GCN 4775, GCN 4776, GCN 4779) on 20 Feb. 2006
(between 14.0 UT to 17.0 UT) at 1280 MHz using a bandwidth of 32 MHz.
We do not detect any source coincident with the position of optical
afterglow (GCN 4779). The 3-sigma upper limit achieved is ~ 0.45 mJy.
We thank GMRT and the National Centre for Radio Astrophysics (NCRA) staff.
This TOO was done under the GMRT Director's Discretionary Time.
GMRT is run by NCRA-TIFR, Pune (INDIA).
This messege may be cited.
GCN Circular 4831
Subject
GRB 060218/SN 2006aj: WIRO optical observations
Date
2006-02-25T09:00:04Z (20 years ago)
From
Chris Rodgers at U of Wyoming <crodgers@uwyo.edu>
C. Rodgers, D. Allen, B. Barlow, C. Garcia, M. Pierce, R. Canterna (U of
Wyoming) report on behalf of the Wyoming Infra-Red Observatory (2.3m) GRB
Team as part of the FUN GRB Collaboration.
GRB 060218/SN 2006aj was observed at the postion reported by Kennea et al.
(GCN 4776) at 2006/02/25 02:03:49 UT in Johnson B. The following B
magnitudes were determined using the USNO B1.0 catalog with a S/N ~ 180.
B (mag) B err (mag) UT
18.250 0.007 02:03:49
18.281 0.006 02:09:48
18.276 0.006 02:33:12
18.295 0.006 02:51:45
18.282 0.007 02:57:13
18.259 0.006 03:14:08
18.245 0.006 03:19:32
18.293 0.011 04:52:09
18.245 0.010 04:57:32
This message may be cited.
GCN Circular 4830
Subject
GRB 060218/SN 2006aj: RBO optical observations
Date
2006-02-25T07:56:19Z (20 years ago)
From
Chris Rodgers at U of Wyoming <crodgers@uwyo.edu>
C. Rodgers (U of Wyoming), D. Allen (U of Wyoming), Marc Herman (U of
Wyoming), R. Rodgers (ACSD#1), R. Canterna (U of Wyoming) report on behalf
of the Red Buttes Observatory (0.6m) GRB Team as part of the FUN GRB
Collaboration.
We responded to the rebrightening of GRB 060218/SN 2006aj at the position
reported by Kennea et al. (GCN 4776) at 2006/02/25 01:47:07 UT. We took
10 minute exposures in BVRI over 4 different epochs. The data are presented
below in magnitudes with a S/N > 14.0. Each of the BRI magnitudes were
obtained using the USNO B1.0 catalog, and the V magntudes were determined
from Cool et al. (GCN 4777) SDSS g and r data by using Smith et al. (2002)
transformation equations.
B V R I UT (B)
18.140 17.116 17.240 16.369 01:47:07
18.134 17.294 17.214 16.248 02:46:14
18.188 17.312 17.243 16.301 03:46:55
18.054 17.288 17.212 16.128 04:30:42
This message may be cited.
GCN Circular 4828
Subject
GRB 060218: Refined analysis of the radio afterglow
Date
2006-02-24T23:31:34Z (20 years ago)
From
Dale A. Frail at NRAO <dfrail@nrao.edu>
Alicia M. Soderberg (Caltech) and Dale A. Frail (NRAO) report on
behalf of a larger collaboration:
"Using additional data we have been able to obtain a flux calibration
of the radio afterglow detected with the VLA on February 20.01 UT
(GCN 4794). At 8.46 GHz the peak flux density was 453 +/- 77 microJy at
a position (epoch J2000) of R.A.=03:21:39.683, dec.+16:52:01.82, with
conservative errors of +/-0.06 arcsec. Further observations are planned.
The National Radio Astronomy Observatory is a facility of the National
Science
Foundation operated under cooperative agreement by Associated
Universities, Inc."
GCN Circular 4822
Subject
GRB 060218/SN 2006aj: Swift-BAT fluence and peak flux
Date
2006-02-23T21:19:22Z (20 years ago)
From
Takanori Sakamoto at NASA/GSFC <takanori@milkyway.gsfc.nasa.gov>
T. Sakamoto (GSFC/ORAU), L. Barbier (GSFC), S. Barthelmy (GSFC),
J. Cummings (GSFC/ORAU), E. Fenimore (LANL), N. Gehrels (GSFC),
D. Hullinger (UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD),
D. Palmer (LANL), A. Parsons (GSFC), G. Sato (ISAS), J. Tueller (GSFC),
on behalf of the Swift-BAT team:
We report further analysis of BAT GRB 060218/SN 2006aj (trigger #191157)
(Cusumano, et al., GCN 4775, Barbier, et al., GCN 4780,
Nousek, et al., GCN 4805).
The time-averaged spectrum from T-8 to T+2732 is best fit by
a simple power-law model. The power law index of the time-averaged
spectrum is 2.5 +- 0.1. The fluence in the 15-150 keV band is
6.8 +- 0.4 x 10^-6 erg/cm2. The peak energy flux in 1.6 sec time
interval starting from T+455.2 sec in the 15-150 keV band is
2.0 +- 1.1 x 10^-8 erg/cm2/sec.
Using the redshift of z=0.033 (Soderberg, et al., GCN 4804), the
isotropic equivalent energy, Eiso, is 1.9 +- 0.1 x 10^49 erg,
and the peak luminosity, Liso, is 6 +- 3 x 10^46 erg/s in
15.5 keV - 154.8 keV at the GRB rest frame. This Eiso is
comparable to that of the one of the softest X-ray flash XRF 020903
observed by HETE-2 (Sakamoto et al., ApJ, 602, 875, Soderberg et al.,
ApJ, 606, 994). The Liso is comparable to that of GRB 980425/SN 1998bw
(Galama et al., Nature, 395, 670). Note that the BAT Eiso and Liso
of GRB 060218 are not bolometric values due to its narrow energy band.
All the quoted errors are at the 90% confidence level. We use
Omega_M = 0.3, Omega_lamda = 0.7, and H0 = 65 in the calculation
of the luminosity distance.
GCN Circular 4819
Subject
GRB 060218: rebrightening
Date
2006-02-23T17:24:47Z (20 years ago)
From
Daniele Fargion at Phys.Dept, Rome Univ1,It <Daniele.Fargion@roma1.infn.it>
The very recent GRB 060218 long burst, brightening,
decline and rebrightening are puzzling, but consistent
with a model for GRB (and later on for SGR),
made by precessing spinning and blazing gamma
collimated Jets (solid angle about 10^-8 sr). See ref. below.
The GRB is associated to a blazing Jet whose
peak power is like a Supernova one (but apparent as GRB power).
In a very small near-by cosmic volumes as GRB 060218 at z=0.0331
or GRB980425 at z=0.008, it is quite off-axis (a few degree).
The off-axis geometry increase the probability to be found and reduce
its apparent luminosity (underluminous GRB).
The spinning-precessing jet lead to inner fast variability,
rebrightenings and while shining away, the smooth GRB decay.
In analogy, but at much lower power and therefore at nearer distances
later on, comparable and longeve X-Jet-pulsars are blazing as SGR.
The persistent precessing jet offer multi optical rebrightening
and-or permits un-correlation with earlier SN.
Hadron material around the SN make the GRB event a
possible TeV source observable by Milagro or ARGO,Hess and MAGIC,
an UHECR source in Auger and Hires,a UHE neutrino source for AMANDA
and Baikal (see DF and M.G. Nuovo Cim. 28 C.N 4-5.p.813-816.
astro-ph/0505150). The GRB maybe obsevable by its PeVs Glashow
neutrino while inducing air-showers at horizons
or EeV Tau air-showers below the MAGIC horizons
(see astro-ph/0511597).
In conclusion:
The presence (but even the already absence)
in near days of a complete SN rise combined with multi-bumps
(optical and-or radio rebrightening)
will stand for a definitive long live
(but decaying) precessing Jet,
blazing within an earlier SN shell.
Its possible late Jet blaze has been and it maybe
observed in future X flare again (if shining online to us).
On the contrary the rise of an unique dramatic SN bump
a few days later the observed brightening
and rebrightening of the GRB,
will be the clear hint that GRB-SN explosion maybe preceeded
by a persistent SGR Jet activity whose culmination ends into a the
catastrophic SN-GRB most powerfull beamed event. This scenario
may be still marginally coexisting with previous one ,
if a Jet activity may trigger the star collapse
and survive the SN explosion.
see D.F.
ATEL # 31; by DF, 15 Jul 1998;
"On the nature of GRB-SGRs blazing jets" in
Astron. Astrophys. Suppl. Ser. 138, 507-508;
and or more recent astro-ph/0501403 in
D.F. Chin.J.Astron.Astrophys.3,3 (2003) 472-482.
This message may be cited
Daniele Fargion
E_mail: daniele.fargion@roma1.infn.it
Phone: +390649914287
Fax: +39064957697
----------------------------------------------
GCN Circular 4818
Subject
Correction to GCN 4816 on GRB060218
Date
2006-02-23T11:32:27Z (20 years ago)
From
Andreas O. Jaunsen at ESO <ajaunsen@astro.uio.no>
Jan-Erik Ovaldsen (ITA) et al. report:
Due to a typo the time of the brightening event was incorrectly
reported in GCN 4816.
The text should read:
"From observations of GRB060218/SN 2006aj (Cusumano et al., GCN #4775)
with DFOSC on the Danish 1.5m telescope at La Silla/ESO we find that
the optical afterglow + SN 2006aj has brightened by 0.2 (+/- 0.01) mag
in R and 0.1 (+/- 0.02) mag in V from Feb 21.03 UT to Feb 22.03 UT. An
optical brightening is in line with the notion that the underlying SN
2006aj has still to reach its maximum, as noted in previous reports."
GCN Circular 4817
Subject
GRB 060218/SN 2006aj: optical observations
Date
2006-02-23T10:37:29Z (20 years ago)
From
Daniele Malesani at SISSA-ISAS,Trieste,Italy <malesani@sissa.it>
D. Malesani (SISSA/ISAS), P. D'Avanzo (INAF/OABr), M. Della Valle
(INAF/OAA), L.A. Antonelli, V. D'Elia, F. Fiore, S. Piranomonte, L.
Stella (INAF/OAR), S. Campana, G. Chincarini, S. Covino, G. Tagliaferri
(INAF/OABr), N. Masetti, E. Palazzi (INAF/IASF Bo), E. Pian (INAF/OATs),
M. Pedani (INAF/TNG) report:
We observed the optical counterpart of GRB 060218 (Cusumano et al., GCN
4775, 4781; Marshall et al., GCN 4800) with the TNG telescope under good
observing conditions. Comparison of the new data with our earlier
photometry (D'Avanzo et al., GCN 4810) reveals further brightening of
the source between Feb 21.85 and Feb 22.86 UT. This is consistent with
the underlying supernova being in the rise phase (Masetti et al., GCN
4803; Soderberg et al., IAUC 8674; Fugazza et al., GCN 4807, CBET 410;
Mirabal et al., CBET 409; Fatkhullin et al., GCN 4809; Mazzali & Pian,
GCN 4812).
This message can be cited.
GCN Circular 4816
Subject
GRB060218: Optical brightening in V and R
Date
2006-02-23T10:35:09Z (20 years ago)
From
Andreas O. Jaunsen at ITA <ajaunsen@astro.uio.no>
Jan-Erik Ovaldsen (ITA), Dong Xu (DARK, NBI), Josefine H. Selj (ITA),
Andreas O. Jaunsen (ITA), Chloe Feron, Christina Thoene, Johan
P. U. Fynbo, and Jens Hjorth (DARK, NBI) report:
From observations of GRB060218/SN 2006aj (Cusumano et al., GCN #4775)
with DFOSC on the Danish 1.5m telescope at La Silla/ESO we find that
the optical afterglow + SN 2006aj has brightened by 0.2 (+/- 0.01) mag
in R and 0.1 (+/- 0.02) mag in V from Feb 20.03 UT to Feb 21.03 UT. An
optical brightening is in line with the notion that the underlying SN
2006aj has still to reach its maximum, as noted in previous reports.
GCN Circular 4812
Subject
Spectral properties of GRB060218/SN2006aj
Date
2006-02-23T02:09:54Z (20 years ago)
From
Elena Pian at ITESRE-CNR,Bologna <pian@iasfbo.inaf.it>
Paolo A. Mazzali (MPA, INAF-Ts) and Elena Pian (INAF-Ts) report:
inspection of the VLT-FORS2 spectrum of GRB060218/SN2006aj taken on 21 Feb
2006 (Masetti et al. 2006, GCN 4803), i.e. ~3 days after the GRB event,
indicates that the observed features are similar to those of the energetic
type Ic SN 2002ap at a comparable epoch (Mazzali et al. 2002, Ap. J. 572,
L21, Fig. 2). In particular, broad absorptions near 4800 Ang and 5800 Ang
can be identified as due to FeII and SiII lines, respectively. This
suggests that the SN and the GRB occurred within ~1 day of one another.
The observed luminosity of the optical counterpart of GRB060218 is larger
than that of SN2002ap at the same epoch, and is consistent with the
luminosity of SN1998bw.
If an afterglow is still present, we estimate that it does not contribute
for more than 25% of the total flux. If it has a power-law shape, this is
not bluer than nu^{-2}.
Although spectroscopy of SN1998bw did not begin until day 8 (Galama et al.
1998, Nature 395, 670), and therefore a direct comparison is not yet
possible, it is likely that SN2006aj will evolve to resemble SN1998bw.
GCN Circular 4810
Subject
GRB 060218: rebrightening
Date
2006-02-22T03:48:28Z (20 years ago)
From
Daniele Malesani at SISSA-ISAS,Trieste,Italy <malesani@sissa.it>
P. D'Avanzo (INAF/OABr), D. Malesani (SISSA/ISAS), M. Della Valle
(INAF/OAA), D. Fugazza (INAF/OABr), N. Masetti, E. Palazzi (INAF/IASF
Bo), E. Pian (INAF/OATs), L.A. Antonelli, V. D'Elia, F. Fiore, S.
Piranomonte, L. Stella (INAF/OAR), S. Campana, G. Chincarini, S. Covino,
G. Tagliaferri (INAF/OABr), L. Di Fabrizio (INAF/TNG), report:
We observed again the optical counterpart of GRB 060218 (Moretti et al.
GCN 4775; Marshall et al., GCN 4779) with the TNG telescope. Comparison
between our previous photometry (taken on Feb 20.85 UT) and the new
observations (Feb 21.84 UT) reveals a rebrightening by 0.20+-0.05 mag in
both the V and R filters.
Following the earlier decay (e.g. Marshall et al., GCN 4800; Berger et
al., GCN 4808), this behaviour may mark the emergence of the underlying
SN 2006aj already suggested on spectroscopic grounds (Masetti et al.,
GCN 4803; Soderberg et al., IAUC 8674; Fugazza et al., GCN 4807, CBET
410; Mirabal et al., CBET 409; Fatkhullin et al., GCN 4809). The
rebrightening may also suggest that the SN is still before its maximum.
This message can be cited.
GCN Circular 4809
Subject
GRB 060218: emergence of the underlying SN spectrum
Date
2006-02-22T01:06:34Z (20 years ago)
From
Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>
T. A. Fatkhullin, V.V. Vlasyuk, V. V. Sokolov, A. V. Moiseev (SAO-RAS Nizhnij Arkhyz),
S. Guziy and A. J. Castro-Tirado (IAA-CSIC Granada), on behalf
of a larger collaboration, report:
"We have obtained optical spectroscopy of the GRB 060218 optical
counterpart (Cusumano et al. GCNC 4775) with the 6.0m BTA telescope
of SAO-RAS in Zelenchuk, equipped with SCORPIO. First epoch
spectroscopy in the 3500-7500 A range was obtained on Feb 20.65 UT,
confirming z = 0.033 (Mirabal and Halpern GCNC 4792). Second epoch
data was gathered on Feb 21.65 UT. Comparison between the two datasets
clearly reveals continuum variations that we interpret as the emergence
of the underlying type-Ic SN spectrum, strengthening the SN-GRB 060218
relationship first suggested by Masetti et al. (GCNC 4803). In
particular, an "emission peak" at ~4500 A is showing up, possibly as
a result of the blending of the Fe lines redward of this feature,
giving rise to a broad absorption trough, as it was seen in the type
Ic SNe 1997ef (Iwamoto et al. 2000, ApJ 534, 660) and 2002ap (Foley
et al. 2003, PASP 115, 1220). Further spectroscopic observations are
encouraged."
[GCN OPS NOTE(22feb06): Per author's request, the 2nd author was added.]
GCN Circular 4808
Subject
GRB 060218: Decline in r-band flux
Date
2006-02-21T22:58:14Z (20 years ago)
From
Edo Berger at Carnegie Obs <eberger@ociw.edu>
E. Berger (Carnegie), B. P. Schmidt (ANU), and A. M. Soderberg (Caltech)
report on behalf of a larger collaboration:
"As part of our spectroscopic observations with GMOS on Gemini-south (GCN
4804) we obtained a single 30-sec r-band image of the field on 2006, Feb
21.01 UT. Calibration against 9 nearby stars from SDSS (GCN 4777) yields
r = 17.92+/-0.12 mag for the afterglow+SN+host. Subtracting off the
contribution of the host (r = 19.93+/-0.03; GCN 4777) we find that the
afterglow+SN faded by 0.43+/-0.22 mag compared to the measurement by
Mirabal (GCN 4784). This corresponds to a decay rate of -0.4+/-0.2, which
is relatively shallow compared to typical optical afterglows, and
furthermore indicates a turnover in the flux evolution following the
initial period of brightening in the B,V bands observed with UVOT (GCN
4800)."
GCN Circular 4807
Subject
GRB 060218: spectroscopic observations
Date
2006-02-21T19:21:07Z (20 years ago)
From
Daniele Malesani at SISSA-ISAS,Trieste,Italy <malesani@sissa.it>
D. Fugazza, P. D'Avanzo (INAF/OABr), D. Malesani (SISSA/ISAS), M. Della
Valle (INAF/OAA), N. Masetti, E. Palazzi (INAF/IASF Bo), E. Pian
(INAF/OATs), L.A. Antonelli, V. D'Elia, F. Fiore, S. Piranomonte, L.
Stella (INAF/OAR), S. Campana, G. Chincarini, S. Covino, G. Tagliaferri
(INAF/OABr), L. Di Fabrizio (INAF/TNG) report:
We observed the optical counterpart of GRB 060218 (Moretti et al., GCN
4775; Marshall et al., GCN 4779; Quimby et al., GCN 4782) with the 3.6m
TNG telescope located at the Canary Islands.
Spectroscopy in the range 4000-8000 AA reveals a blue continuum with
prominent star-forming emission features (Mirabal & Halpern, GCN 4792;
Masetti et al., GCN 4803).
A weak, broad bump is seen at ~5000 A, which is consistent with the peak
of a broad-lined SN like SN\1998bw (see also Masetti et al., GCN 4803;
Soderberg et al., GCN 4804). The overall observed shape would imply a
roughly equal contribution from the afterglow and the SN.
This message can be cited.
GCN Circular 4806
Subject
GRB 060218: Further refined analysis of the Swift-BAT burst
Date
2006-02-21T19:17:31Z (20 years ago)
From
Scott Barthelmy at NASA/GSFC <Scott@lheamail.gsfc.nasa.gov>
S. Barthelmy (GSFC), J. Cummings (GSFC/NRC), T. Sakamoto (GSFC/NRC),
C. Markwardt (GSFC/UMD), N. Gehrels (GSFC)
on behalf of the Swift-BAT team:
Using the data set from T-50 to T+2000 sec from telemetry downlinks,
we report further analysis of BAT GRB 060218 (trigger #191157)
(Cusumano, et al., GCN 4745; Barbier, et al., GCN 4780; Gehrels, GCN 4787).
The BAT ground-calculated position is RA,Dec = 50.379,+16.904 deg
{3h 21m 30.9s, 16d 54' 14.2"} (J2000) +- 2.6 arcmin, (radius, sys+stat,
90% containment). The partial coding was 88%.
Extending the mask-weighted lightcurve beyond T+120 sec (GCN 4780),
it continues the weak, flat, soft emission out to T+280 sec. This flux
is 0.06 +- 0.02 counts/cm2/sec in the 15-50 keV band. At T+290 sec
there is a 10-sec wide spike which is spectrally harder than the
flat emission (all the emission is in the 25-100 keV band).
Starting at ~T+200 the lightcurve starts an approximately
linear increase to a peak flux of 0.1 counts/cm2/sec (15-100 keV),
and then begins a roughly exponential decay out to at least
T+2000 sec.
We note that this is a very long event. It is among the very longest
of GRBs. At this point, using BAT results alone, we can not rule out
a non-GRB nature for this event.
GCN Circular 4805
Subject
GRB 060218: Likely an underluminous GRB
Date
2006-02-21T19:13:26Z (20 years ago)
From
John Nousek at Penn State U/Swift <nousek@astro.psu.edu>
J. Nousek (PSU), G. Cusumano (IASF-Pa INAF), A. Moretti (INAF-OAB), G.
Tagliaferri
(INAF-OAB), S. Campana (INAF-OAB), J. Kennea (PSU), D. Burrows (PSU), P. Roming
(PSU), D. VandenBerk (PSU), P. Brown (PSU), N. Gehrels (GSFC), S. Barthelmy
(GSFC), F. Marshall(GSFC), P. Boyd (GSFC), T. Sakamoto (GSFC), J. Osborne
(U. Leicester), P. O'Brien (U. Leicester), G. Chincarini (Univ.
Milano-Bicocca),
B. Zhang (UNLV) and M. de Pasquale (MSSL)
report on behalf of the Swift Team:
The Swift team now believes that GRB 060218 is most likely an underluminous
GRB. This view is supported by the remarkably long duration of the prompt
emission seen by all three Swift instruments and the probable association
with a
low-z (z=0.033) galaxy (Mirabel GCN 4783; Masetti et al GCN 4803). Although
there are unusual aspects to this event (cf. Gehrels GCN 4787), the high
galactic
latitude seems to make a Galactic X-ray transient origin unlikely. Moreover,
the extremely rapid X-ray decay after T+3000 seconds (3 orders of magnitude
in an hour), followed by a slow power law decay in time (alpha = 1.2), looks
very much like a normal GRB XRT lightcurve.
We also draw attention to the chromatic nature of the Swift light curves.
The BAT emission peaked substantially earlier than the XRT emission,
which preceded the UVOT emission peak. Although the low
luminosity inferred from the low-z might suggest a highly off-axis viewing
angle for this burst, an off-axis burst should show achromatic emission
variation, which is not seen here (see predictions by Kumar, P. & Granot, J.
2003, ApJ, 591, 1075, for example.)
The burst continues to be bright in the UVOT, (V= 18.29 +/- 0.07
at 21:29 UT on 20 Feb 2006), so we suggest additional follow-up observations
that might confirm signatures of a host supernova or other evidence that
might clarify the nature of this highly unusual GRB.
GCN Circular 4804
Subject
GRB060218: Optical Spectroscopy of GRB-SN
Date
2006-02-21T19:11:20Z (20 years ago)
From
Alicia Soderberg at Caltech <ams@astro.caltech.edu>
A. M. Soderberg (Caltech), E. Berger (Carnegie), and B. P. Schmidt (ANU)
report on behalf of a larger collaboration:
"We obtained an optical spectrum of the afterglow of GRB 060218 (GCN 4775)
with GMOS on the Gemini-south telescope starting on 2006 Feb 21.024 UT,
for a total of 1800 sec. We confirm the presence of narrow emission lines
at z=0.033 (GCNs 4792,4803), as well as the presence of broad absorption
features similar to those seen in SN1998bw and other broad-lined
Type Ibc supernovae (GCN 4803).
A plot of our spectrum is available at:
http://www.ociw.edu/~eberger/grb060218_gemini.ps
Further observations are planned."
GCN Circular 4803
Subject
GRB060218: VLT spectroscopy
Date
2006-02-21T16:59:19Z (20 years ago)
From
Nicola Masetti at INAF-IASF,Bologna <masetti@iasfbo.inaf.it>
N. Masetti, E. Palazzi (INAF-IASF, Bologna), E. Pian (INAF, OA
Trieste) and F. Patat (ESO), on behalf of the GRACE collaboration, report:
"On 2006 February 21.051 UT we acquired a 30-min spectrum of the optical
transient associated with the possible GRB060218 (Cusumano et al., GCN
4775) with VLT-Antu equipped with FORS2 and low resolution grating
300V+GG435. We confirm the presence of narrow nebular lines at redshift
z = 0.033 (Mirabal & Halpern, GCN 4792). We also note that the spectral
continuum shows an overall shape which resembles that of supernova 1997ef
around maximum (Iwamoto et al., 2000, ApJ, 534, 660).
This may suggest that, if this object is a SN associated with GRB060218,
it is either rapidly evolving or it exploded days before the GRB.
We acknowledge the assistance of the ESO-Paranal staff.
This message may be cited."
GCN Circular 4802
Subject
GRB 060218: Optical Observations at Xinglong Obs.
Date
2006-02-21T15:17:57Z (20 years ago)
From
Yulei Qiu at Nat.Astro.Obs.of China <qiuyl@ns.bao.ac.cn>
W.K. Zheng, M.Zai, Y.L. Qiu, J.Y. Wei,J.Y. Hu and J.S Deng
reports on behalf of the Xinglong GRB follow-up team report:
"We observed the optical counterpart of the GRB 20060218
(Cusumano et al. (GCN 4775)) with the 0.8m and the 1m telescopes
at Xinglong Observatory, National Astronomical Observatories,
Chinese Academy of Sciences. We began observations in R band
7.1953 hours after the trigger. Preliminary analyses show the
object has a R magnitude of 17.79 0.1 on Feb 18.4522 UT
and 18.25 0.1 on Feb 20.4471 UT (reference stars from
USNO-A2.0), which is brighter than the pre-burst counterpart
observed by SDSS(GCN 4777). Further analysis is under processing."
This message may be cited
GCN Circular 4800
Subject
GRB060218: UV Detection and Light Curves
Date
2006-02-21T01:17:18Z (20 years ago)
From
Frank Marshall at GSFC <marshall@milkyway.gsfc.nasa.gov>
F. Marshall (GSFC), P. Brown (PSU), S. Immler (GSFC/USRA), and
G. Cusumano (IASF-Pa INAF) report on behalf of the Swift team:
The optical counterpart of the unusual GRB 060218
(Cusumano et al. (GCN 4775), Marshall et al. (GCN 4779))
is detected in all 6 of the Swift/UVOT broad-band filters
(V, B, U, UVW1, UVM2, UVW2). The filters collectively cover
the wavelength range from 180 to 560 nm. The light curves
for all the filters have similar shapes. The emission steadily
brightens by 1 to 2 magnitudes from the first detection about
150 s. after the burst trigger, peaks in a broad plateau
about 10 hours after the trigger, and then slowly declines for
at least the next 20 hours. Peak magnitudes
are 17.8, 17.7, 16.3, 16.2, 16.1, and 16.0 for the
V, B, U, UVW1, UVM2, and UWW2 filters respectively.
UVOT observations are continuing.
GCN Circular 4794
Subject
GRB060218: Radio Afterglow Discovery
Date
2006-02-20T04:24:40Z (20 years ago)
From
Alicia Soderberg at Caltech <ams@astro.caltech.edu>
Alicia M. Soderberg (Caltech) and Dale A. Frail (NRAO) report on behalf
of a large collaboration:
"We observed the field of GRB 060218 (GCN 4775) with the Very Large Array
at 8.46 GHz on February 20.0 UT. We detect a source coincident with the
optical afterglow candidate (GCN 4779) and host galaxy (GCN 4783).
Further observations are planned."
GCN Circular 4792
Subject
GRB 060218: MDM Redshift
Date
2006-02-20T03:32:23Z (20 years ago)
From
Jules Halpern at Columbia U. <jules@astro.columbia.edu>
N. Mirabal (U. Michigan) and J. P. Halpern (Columbia U.) report on behalf
of the MDM Observatory GRB follow-up team:
"We obtained a low-resolution spectrum of the optical afterglow and
host galaxy of GRB 060218 using the MDM 2.4m telescope and Boller &
Chivens (CCDS) Spectrograph on Feb. 20 02:20 UT. Strong, narrow emission
lines of H-beta, [O III] 4959,5007, and H-alpha at z=0.0331 are seen,
superposed on a blue continuum, which is still much brighter than the
SDSS pre-burst magnitudes. The line ratios are typical of a high-excitation
starburst. This confirms the low-redshift, extragalactic nature of this
unusual GRB.
This message may be cited."
GCN Circular 4790
Subject
GRB 060218: optical/nIR observations at La Palma
Date
2006-02-20T01:59:46Z (20 years ago)
From
Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>
A. de Ugarte Postigo, A. J. Castro-Tirado,
S. B. Pandey (IAA-CSIC, Granada), D. Barrado-
Navascu�s, A. Bayo, B. Montesinos (LAEFF-INTA, Madrid),
K. Mishra (ARIES, Nainital),and S. Dehaes
(Inst. voor Sterrenkunde, K.U. Leuven), on
behalf of a larger collaboration report:
"Following the detection by SWIFT of "GRB" 060218
(Cusumano et al. GCN Circ. 4770, Gehrels et al.
GCN Circ. 4787) we have obtained UBVRIJHK images
with the 1.2m Mercator (+MEROPE) and 3.5m TNG (+NICS)
telescopes at La Palma (Canary Islands), starting on
Feb 19.85 UT (i.e. 40.8 hr after the event).
We detect a near-IR counterpart to the hard energy
source on a stacked 150s image in the K'-band with
K about 17 (with respect to 2MASS catalogue).
Astrometry against USNO-A2.0 yields RA(2000) =
03 21 39.71, Dec(2000) = +16 52 02.1 (+/-0.5").
This position is fully consistent with the optical
counterpart proposed by Cusumano et al. (op. cit.)
and Marshall et al. (GCN Circ. 4779) and with the
faint object reported by Mirabal (GCN Circ. 4783)
on the SDSS archival data (Cool et al. GCN Circ.
4777). However, we do not find evidence of underlying
extended emission in our K'-band frame (0".7 seeing).
Together with the fact that the colour index of the
source is J-K = 0, unlike GRB afterglow colours
(see fig. 2 of Gorosabel et al. 2002, A&A 384, 11),
it clearly favours a high-energy transient in our
Galaxy."
This Circular might be cited.
[GCN OPS NOTE(20feb06): Per author's request, A. Bayo
was added to the author list.]
GCN Circular 4787
Subject
Oddball GRB 060218, transient or GRB?
Date
2006-02-19T21:49:58Z (20 years ago)
From
Neil Gehrels at GSFC <gehrels@gsfc.nasa.gov>
N. Gehrels (NASA-GSFC) on behalf of the Swift team:
We point out that GRB 060218 (Cusumano et al. GCN 4775) is a
strange event. It has
- a gamma-ray light curve that is flat and a soft spectrum
(Barbier et al. GCN 4780)
- an X-ray light curve with a long, slow rise and gradual
decline (Cusumano et al. GCN 4786)
- an optical light curve with brightening after 10 hours
(Marshall et al. GCN 4785).
These characteristics are unlike previous GRBs.
It has properties that are also atypical of a transient:
- it is far off the galactic plane (b = -32.9 deg) and
far away from the bulge (l = 166.9 deg)
- there is a possible association (Mirabel GCN 4783) with
a galaxy in the SDSS pre-burst field (Cool et al. GCN 4777).
Further observations are warranted.
GCN Circular 4786
Subject
GRB060218: Swift/XRT Team preliminary analysis of the possible burst
Date
2006-02-19T13:54:11Z (20 years ago)
From
Giancarlo Cusumano at INAF-IASFA <cusumano@pa.iasf.cnr.it>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 8bit
G. Cusumano (IASF-Pa INAF), A. Moretti (INAF-OAB), G. Tagliaferri
(INAF-OAB), J. Kennea (PSU) and D. Burrows (PSU), report on behalf of
the Swift/XRT Team:
We analised the first 14 orbits of data (the first orbit is fully in
Windowed Timing (WT) mode, the second is in WT mode for the first 84
seconds, the rest of the data are all in Photon Counting (PC) mode). The
following refined position for the X-ray afterglow was determined:
RA(J2000) = 03h 21m 39.7s
Dec(J2000) = +16d 52' 01.8"
with an estimated uncertainty of 3.6 arcsec (90% containment). This is
3.0 arcmin from the BAT position reported in GCN 4780, 3.4 arcsec from
the XRT position given in GCN 4781 and 0.8 arcsec from the UVOT source
given in GCN 4779.
The WT light curve starts 159 s after the BAT trigger with a count rate
that rises from about 40 counts/s up to about 110 counts/s. The peak
occurs around 990 s after the trigger, then the count rate decays and at
2770 s after the trigger, when the first observation orbit ends, the
count rate is about 50 counts/s. At the beginning of the second orbit
(5944 s post-trigger) the count rate has faded to a value of about 1.1
cts/s and decays very fast. The light curve after the first orbit is
modelled by a broken power law characterized by a decay index of 6.38 �
0.05 up to 9250 � 270 s post trigger, followed by an intensity decrease
with a decay index of 1.15+/- 0.15.
The light curve can be seen at
http://www.merate.mi.astro.it/~moretti/lc_060218.gif
The spectrum obtained for the first orbit of data (159 - 2770 s
post-trigger) can be fitted with a power-law of photon index Gamma =
1.82 � 0.01, with an absorbing column density of (1.9 � 0.01)e21 cm^-2
in excess of the Galactic column of 1.1e21 cm^-2. Over this time span,
the mean 0.2-10 keV observed (unabsorbed) flux is 3.6e-9 (5.6e-9) erg
cm^-2 s^-1.
The spectrum obtained in the following orbits can be fitted with a
power-law of photon index Gamma = 3.3 � 0.2, with an excess of absorbing
column density of (3.2 � 0.4)e21 cm^-2. The mean 0.2-10 keV observed
(unabsorbed) flux is 1.5e-12 (1.4e-11) erg cm^-2 s^-1.
If the burst continues to decay at the current rate we estimate an XRT
count rate of 2.5e-3 counts/s at T+48hr, which corresponds to an
unabsorbed 0.2-10 keV flux of 7.6e-13 erg cm^-2 s^-1.
The long, slow flux increase and gradual decrease are unlike any
previous GRB prompt or afterglow emission seen by the XRT. Combined
with the unusual spectral evolution, this suggests that this source may
be an X-ray transient rather than a GRB.
This circular is an official product of the Swift XRT Team.
GCN Circular 4785
Subject
Brightening of the Optical Counterpart of the Possible GRB 060218
Date
2006-02-19T06:07:32Z (20 years ago)
From
Frank Marshall at GSFC <marshall@milkyway.gsfc.nasa.gov>
F. Marshall (GSFC), S. Immler (GSFC/USRA) and G. Cusumano (IASF-Pa INAF)
report on behalf of the Swift team:
Continuing UVOT observations of the possible GRB 060218 show that
the candidate optical afterglow reported by Cusumano et al. (GCN 4775)
and Marshall et al. (GCN 4779) has brightened by a factor of about 5
in the 10 hours since the BAT trigger. Consequently, this source is unlikely
to be the optical afterglow of a GRB. This brightening, the extended emission
detected with BAT, and the possible BAT detection a month earlier
(Barbier et al. GCN 4780) suggest that the UVOT source is the optical
counterpart of a hard X-ray transient.
GCN Circular 4784
Subject
GRB 060218: MDM Observations
Date
2006-02-19T04:26:33Z (20 years ago)
From
Nestor Mirabal at U Michigan <mirabal@umich.edu>
N. Mirabal (U. Michigan) reports on behalf of the MDM Observatory GRB
follow-up team:
"I observed the candidate optical afterglow of Swift GRB 060218 detected
by the Swift UVOT (Cusumano et al. GCN #4775, Marshall et al. GCN #4779,
Quimby et al. GCN #4782) with the MDM 2.4m telescope and RETROCAM imager
under partly cloudy conditions. Calibration with SDSS pre-burst
observations (Cool et al. GCN #4777) yields r = 17.55 +/- 0.1 on Feb.
19.1438 UT for the OT. This is brighter than the pre-burst observations
and confirms it as the OT of GRB 060218."
GCN Circular 4783
Subject
GRB 060218: Pre-burst detection of a possible host galaxy
Date
2006-02-19T02:55:07Z (20 years ago)
From
Nestor Mirabal at U Michigan <mirabal@umich.edu>
N. Mirabal (U. Michigan) reports:
"Analysis of the SDSS pre-burst observations of the GRB 060218 field
(Cool et al. GCN #4777) reveals an extended object at 03h21m39.68s
+16:52:01.66 (J2000). Given the proximity of this object to the reported
XRT and UVOT positions for a candidate afterglow (Cusumano et al. GCN
#4775, Marshall et al. GCN #4779), this should be considered a potential
host galaxy of a low-redshift GRB. Further multiwavelength observations
are encouraged to confirm the reality of this trigger (Barbier et al. GCN
#4780), and its possible association with this nearby galaxy. I
acknowledge useful conversations with Richard Cool."
GCN Circular 4781
Subject
GRB060218: Swift/XRT refined position of a possible burst
Date
2006-02-18T23:18:46Z (20 years ago)
From
Giancarlo Cusumano at INAF-IASFA <cusumano@pa.iasf.cnr.it>
G. Cusumano (IASF-Pa INAF), A. Moretti (INAF-OAB), G. Tagliaferri
(INAF-OAB), J. Kennea (PSU) and D. Burrows (PSU), report on behalf of
the Swift/XRT Team:
We have performed a preliminary analysis of Swift/XRT ground-linked data
associated to the possible burst GRB060218 (trigger=191157; Cusumano et
al., GCN 4775, Kennea et al. 4776). We confirm the presence of a bright
X-ray source at the following location:
RA(J2000): 3h 21m 39.9s
Dec(J2000): 16d 52m 03.7s
with an estimated uncertainty of 7 arcseconds (90% containment). Note
that this position lies 3.7" from the previous XRT position (GCN 4775),
3' from the BAT position reported in GCN 4780 and 2.9" from the UVOT
position. A full analysis of the XRT data will follow.
This circular is an official product of the Swift XRT Team.
GCN Circular 4779
Subject
Further UVOT Observations of the Candidate Optical Afterglow for GRB 060218
Date
2006-02-18T17:01:28Z (20 years ago)
From
Frank Marshall at GSFC <marshall@milkyway.gsfc.nasa.gov>
F. Marshall (GSFC), S. Immler (GSFC/USRA) and G. Cusumano (IASF-Pa INAF)
report on behalf of the Swift team:
The UVOT source reported by Cusumano et al. (GCN 4775) is detected in all
four UVOT finding chart exposures ranging from 153s to 1036s
from the burst trigger as shown in the table below. There is marginal
evidence for brightening in the V filter. The revised source position is
03:21:39.71 +16:52:02.6 (J2000) with an estimated 1-sigma error of about 1.0".
This position is within the XRT error circle (Kennea et al. GCN 4776).
We note the existence of a source in the USNO-B1 catalog
at 03:21:39.69 +16:52:02.2 with a B2 magnitude of 20.67
and an R2 magnitude of 20.3. Further UVOT observations
are underway to search for fading of this afterglow candidate.
T_start Exposure Filter Mag Mag. Range (1-sigma)
153 200 V 19.6 19.1 - 20.3
359 155 B 19.4 19.2 - 19.6
830 127 B 19.3 19.1 - 19.5
1036 148 V 18.4 18.2 - 18.6
GCN Circular 4777
Subject
GRB060218 : SDSS pre-burst observations
Date
2006-02-18T11:27:26Z (20 years ago)
From
Richard J. Cool at U.of AZ/Steward Obs <rcool@as.arizona.edu>
Richard J. Cool (Arizona), Daniel J. Eisenstein (Arizona),
David W. Hogg (NYU), Michael R. Blanton (NYU), David
J. Schlegel (LBNL), J. Brinkmann (APO), Donald P. Schneider
(PSU), and Daniel E. Vanden Berk (PSU) report:
The Sloan Digital Sky Survey (SDSS) imaged the field of
burst GRB060218 prior to the burst. As these data should
be useful as a pre-burst comparison and for calibrating
photometry, we are supplying the images and photometry
measurements for this GRB field to the community.
Data from the SDSS, including 5 FITS images, 3 JPGS, and
3 files of photometry and astrometry, are being placed
at http://mizar.as.arizona.edu/~grb/public/GRB060218
We supply FITS images in each of the 5 SDSS bands of a
8'x8' region centered on the GRB position (ra=50.4154
(03:21:39.7), dec=16.8670 (16:52:01.3); GCN 4776),
as well as 3 gri color-composite JPGs (with different
stretches). The units in the FITS images are nanomaggies
per pixel. A pixel is 0.396 arcsec on a side. A nanomaggie
is a flux-density unit equal to 10^-9 of a magnitude
0 source or, to the extent that SDSS is an AB system,
3.631e-6 Jy. The FITS images have WCS astrometric
information.
In the file GRB060218_sdss.calstar.dat, we report
photometry and astrometry of 308 bright stars (r<20.5)
within 15' of the burst location. The magnitudes presented
in this file are asinh magnitudes as are standard in the
SDSS (Lupton 1999, AJ, 118, 1406). Beware that some of
these stars are not well-detected in the u-band; use the
errors and object flags to monitor data quality.
In the files GRB060218_sdss.objects_flux.dat and
GRB060218_sdss.objects_magnitudes.dat, we report photometry
of 947 objects detected within 6' of the GRB position.
We have removed saturated objects and objects with
model magnitudes fainter than 23.0 in the r-band.
The fluxes listed in GRB060218_sdss.objects_flux.dat
are in nanomaggies while the magnitudes listed in
GRB060218_sdss.objects_magnitudes.dat are asinh magnitudes.
All quantities reported are standard SDSS photometry,
meaning that they are very close to AB zeropoints
and magnitudes are quoted in asinh magnitudes.
Photometric zeropoints are known to about 2% rms.
None of the photometry is corrected for dust extinction.
The Schlegel, Finkbeiner, and Davis (1998) predictions
for this region are A_U=0.749 mag, A_g=0.551 mag, A_r =
0.400 mag, A_i=0.303 mag, and A_z=0.215 mag.
There are currently no objects within 6 arcminutes of the
GRB position in the SDSS spectroscopic database.
SDSS astrometry is generally better than 0.1 arcsecond
per coordinate. Users requiring high precision astrometry
should take note that the SDSS astrometric system can
differ from other systems such as those used in other
notices; we have not checked the offsets in this region.
More detailed information pertaining to our SDSS GRB
releases can be found in our initial data release paper
(Cool et al. 2006, astro-ph/0601218). See the SDSS DR4
documentation for more details: http://www.sdss.org/dr4.
These data have been reduced using a slightly different
pipeline than that used for SDSS public data releases.
We cannot guarantee that the values here will exactly match
those in the data release in which these data are included.
In particular, we expect the photometric calibrations to
differ by of order 0.01 mag.
This note may be cited, but please also cite the SDSS data
release paper, Adelman-McCarthy et al. (2006, ApJS, in
press, astro-ph/0507711), when using the data or referring
to the technical documentation.
GCN Circular 4776
Subject
GRB 060218: Swift XRT Position
Date
2006-02-18T10:49:54Z (20 years ago)
Edited On
2025-04-09T18:44:56Z (6 months ago)
From
Giancarlo Cusumano at INAF-IASFA <cusumano@pa.iasf.cnr.it>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Tyler Barna at University of Minnesota <tylerpbarna@gmail.com>
J. A. Kennea, D. N. Burrows (PSU), G. Cusumano (INAF-Pa), and G.
Tagliaferri (INAF-OAB) report on behalf of the Swift XRT team:
The Swift XRT observed the position of GRB 060218 (Cusumano et al., GCN
4775) beginning at 03:37:04 UT, 153 s after the BAT trigger. The
on-board centroiding algorithm did not find a source. Ground-processing
of the data was delayed, but we have now partially analyzed data from
the first two orbits, using Level 0 data from the MOC. The XRT was in
Windowed Timing mode for the entire first orbit and therefore no
position is available from that orbit. The XRT switched into PC mode
during the second orbit, during which we clearly detect a bright, fading
point source located at:
RA(J2000): 03h 21m 39.7s
Dec(J2000): 16d 52' 01.33"
We estimate the uncertainty to be about 5 arcseconds (90% confidence
radius). This position lies 39 arcseconds from the BAT position reported
in GCN 4775. A full analysis of the XRT data will follow.
This circular is an official product of the Swift XRT Team.
GCN Circular 4775
Subject
GRB 060218: Swift-BAT detection of a possible burst
Date
2006-02-18T04:28:55Z (20 years ago)
From
Scott Barthelmy at NASA/GSFC <Scott@lheamail.gsfc.nasa.gov>
G. Cusumano (IASF-Pa INAF), S. Barthelmy (GSFC), N. Gehrels (GSFC),
S. Hunsberger (PSU), S. Immler (GSFC), F. Marshall (GSFC),
D. Palmer (LANL), T. Sakamoto (GSFC/ORAU)
on behalf of the Swift team:
At 03:34:30 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 060218 (trigger=191157). Swift slewed immediately to the burst.
The BAT on-board calculated location is RA,Dec 50.404, +16.866 deg
{03h 21m 37s, +16d 51' 58"} (J2000) with an uncertainty of 3 arcmin
(radius, 90% containment, including systematic uncertainty). The TDRSS
lightcurve shows nothing, which is consistent and common for an image trigger.
The XRT began taking data at 03:37:04 UT, 153 seconds after the BAT trigger.
The XRT on-board centroid algorithm did not find a source in the image and
no prompt position is available. We are waiting for down-linked data
to detect and determine a position for the source.
The UVOT began taking data 152 seconds after the BAT trigger.
There is an indication of an afterglow candidate at RA,Dec
03h 21m 39.8s,+16d 52' 06" +/- 1 arcsec with an estimated B magnitude of 19.4.