GRB 020405
GCN Circular 1458
Subject
GRB 020405: HST observations reveal red bump
Date
2002-07-23T07:15:10Z (23 years ago)
From
Paul Price at RSAA, ANU <pap@mso.anu.edu.au>
P.A. Price (RSAA, ANU), S.R. Kulkarni, D.W. Fox and J.S. Bloom
(Caltech) report on behalf of the larger Caltech-NRAO-CARA GRB
collaboration:
We observed the afterglow of GRB 020405 (GCN #1326) with HST+WFPC2 at
several epochs spanning 19-31 days after the GRB in F555W, F702W and
F814W, with additional observations approximately two months after the
GRB to remove host contamination. These observations formed part of
our large Cycle 10 program to search for SNe underlying low redshift
GRBs.
We have performed Novicki-Tonry photometry (see astro-ph/0207187) on
both ground-based and HST imaging. The resultant light curve,
including data from Bersier et al. (astro-ph/0206465), is at
http://www.mso.anu.edu.au/~pap/grb020405/ .
An excess of flux is evident in the HST images, compared to an
extrapolation of the light-curve from early times. Based on the red
colour and the time of peak emission, we identify this excess as a SN
associated with GRB 020405. We have plotted the light-curve of SN
1998bw at z=0.695 (Masetti et al., GCN #1330) and dimmed by 0.5 mag as
a comparison. This SN appears to be red relative to SN 1998bw, but
this is sensitive to the amount of flux in the afterglow at the final
available HST images. Further HST observations to measure the host
galaxy and remove this ambiguity are planned for August.
This message may be cited.
GCN Circular 1431
Subject
GRB020405: polarimetric observations
Date
2002-06-19T10:15:48Z (23 years ago)
From
Stefano Covino at Brera Astronomical Observatory <covino@merate.mi.astro.it>
S. Covino, G. Ghisellini, D. Malesani, P. Saracco, G. Tagliaferri, F. Zerbi
(Observ. of Brera, Milan, Italy); S. Di Serego, A. Cimatti, M. Della Valle
(Observ. of Arcetri, Florence, Italy); F. Fiore, G.L. Israel, L. Stella
(Observ. of Monte Porzio, Rome, Italy); M. Vietri (Univ. Rome 3, I); N. Kawai
(Tokyo Tech, Japan); D. Lazzati (IoA, Cambridge, UK); S. Ortolani (Univ. of
Padua, Italy); L. Pasquini (ESO, Germany); G. Ricker (MIT, USA); E. Le Floch,
P. Goldoni, F. Mirabel (CEA, F) report:
On 2002 April 7.21 and April 8.26 we observed the optical counterpart to
GRB020405. The observations were performed with the ESO VLT-3 (Melipal)
telescope equipped with FORS1 with a Bessel V band filter in the imaging
polarimetry mode. The transient source is clearly detected superposed to a
bright galaxy. The acquisition images allowed us to derive the magnitude of
the transient as reported in GCN 1337 and GCN 1345 (Covino et al.).
On April 7.21 (2.1 days after the GRB) we found linear polarization at the
level of 1.93 +/- 0.33 per cent with position angle 154 +/- 5 degrees while
on April 8.26 (3.2 days after the GRB) we found linear polarization at the
level of 1.23 +/- 0.43 per cent with position angle 168 +/- 9 degrees.
Polarization measurements were corrected for any instrumental effect or
measurement bias and the reported polarization degrees and position angles
are derived from Stokes parameters normalized to the average of the field
stars.
This message is citeable.
GCN Circular 1388
Subject
GRB020405 field photometry at ESO
Date
2002-05-10T16:25:52Z (23 years ago)
From
Nicola Masetti at ITeSRE,CNR,Bologna <masetti@tesre.bo.cnr.it>
A. Simoncelli, E. Maiorano (U. Bologna), E. Palazzi, N. Masetti
(IASF/CNR, Bologna), E. Pian (INAF, OA Trieste), J. Hjorth (U.
Copenhagen), A. Castro-Tirado (IAA-CSIC, Granada), A. Fruchter
(STScI, Baltimore), J. Greiner (MPE Garching and AI Potsdam), L.
Kaper, E. van den Heuvel (U. Amsterdam), A. Delsanti, M. Billeres
(ESO), on behalf of the GRACE Collaboration, report:
"We have acquired BVRcIc photometry of the field of GRB020405 with the
Danish 1.54m and NTT 3.58m ESO telescopes at La Silla, Chile.
We placed the photometric data of 6 selected stars, together with an
R-band image of the field on which the stars are marked, at the URL:
http://tonno.tesre.bo.cnr.it/~masetti/grb020405_phot.html
The current photometry has a potential external zero-point error of about
three percent that needs to be added in quadrature to the Poisson errors
given for the magnitude uncertainties of the selected stars.
Specifically, the magnitudes of the USNO-A2.0 stars 0525-16813005 and
0525-16815468 (Palazzi et al., GCN #1328; Hjorth et al., GCN # 1329),
which are labeled as stars # 2 and # 5 of our sample, are
V = 19.01 +- 0.01, R = 18.48 +- 0.01 for the first one and
V = 17.92 +- 0.01 for the second.".
This message can be cited.
GCN Circular 1375
Subject
GRB020405: VLT observations of the OT environment
Date
2002-04-18T14:18:16Z (23 years ago)
From
Nicola Masetti at ITeSRE,CNR,Bologna <masetti@tesre.bo.cnr.it>
N. Masetti, E. Palazzi (IASF/CNR, Bologna), E. Maiorano, A. Simoncelli
(U. Bologna), E. Pian (INAF, OA Trieste), A. Castro-Tirado (IAA-CSIC,
Granada), A. Fruchter (STScI, Baltimore), J. Greiner (MPE Garching
and AI Potsdam), J. Hjorth (U. Copenhagen), L. Kaper, E. van den Heuvel
(U. Amsterdam), R. Cabanac, A. Kaufer (ESO), on behalf of the GRACE
Collaboration, report:
"We have obtained an R-band image (2 x 3 minutes integration) of GRB020405
from VLT-UT3 (Melipal) plus FORS1 on 2002 Apr. 15.244 under a seeing of
0.65 arcsec.
We find that the OT is located within a complex environment composed of
at least four extended objects, one of which is underlying the OT and
showing a bright knot (possibly a star-forming region, or alternatively
the host nucleus) ~1 arcsec south of the OT itself.
Also, the presumed host galaxy indicated by Hjorth et al. (GCN #1329)
and located ~2 arcsec southwest of the OT seems not to be the actual host
but a galaxy which is likely interacting with it.
Indeed, a spectrum of this galaxy taken with Melipal+FORS1 on
2002 April 7.310 shows that it is at the same redshift of the OT
(GCNs #1330, #1340).
This finding strengthens the suggestion that GRBs are sometimes associated
with interacting galaxies possibly displaying substantial star formation,
as seen e.g. for GRB001007 (Castro Ceron et al. 2002, A&A, in press
[astro-ph/0110049]).
No suggestion of a break in the light curve (see GCN #1369) is apparent
up to ~10 days after the GRB.
However, in the VLT image reported above, the OT brightness is already
substantially contamined by the host emission. For this reason it would
be quite difficult to see any future possible break in the OT light
curve with ground-based observations.
A close-up of the VLT R-band field around the OT can be found at:
http://tonno.tesre.bo.cnr.it/~masetti/grb020405.html
This message can be cited.".
GCN Circular 1369
Subject
GRB020405: predicted break
Date
2002-04-13T16:03:45Z (23 years ago)
From
Daniele Malesani at Obs.Astro. di Brera <malesani@merate.mi.astro.it>
D. Malesani, G. Ghisellini, S. Covino (Brera Observ., Milan) and
D. Lazzati (IoA Cambridge, UK) report:
According to the idea of Frail et al. (2001, ApJ, 562, L55) that the jet
energies of GRBs are universal, an achromatic jet break in the afterglow
lightcurve is predicted for all bursts at the time
t_jet = 20.4 (1+z) / (E_gamma/1e52) days,
where E_gamma is the observed (i.e. isotropic) energy of the prompt
emission. This result is independent of the unknown efficiency and
circumburst density.
For GRB020405, with z=0.69 (GCN 1330 and GCN 1340) and E_gamma>4.3e52
erg (assuming H_0=65, Omega_m=0.3, Omega_Lambda=0.7 and taking the
fluence to be larger than the reported value in the 25-100 keV band:
3e-5 erg/cm2, GCN 1325), we have t_jet<8 days. Hence the break
should have occured before April 13.
Our V-band data (GCN 1337, 1345) connect very well with a previous
measurement by Palazzi et al. (GCN 1328), who use the same calibration
stars. The decay slope is hence very well defined (1.52+-0.04), making
easier the possible detection of the predicted break (see the lightcurve
at: http://www.merate.mi.astro.it/~gabriele/020405.html ).
Since both the detection or the non-detection of the break would be very
important to constrain Frail et al. idea, we urge photometric
observations of the afterglow of this burst.
This message can be cited.
GCN Circular 1345
Subject
GRB020405: VLT optical observations and V band decay slope
Date
2002-04-09T12:52:29Z (23 years ago)
From
Stefano Covino at Brera Astronomical Observatory <covino@merate.mi.astro.it>
S. Covino, G. Ghisellini, P. Saracco, G. Tagliaferri, F. Zerbi
(Observ. of Brera, Milan, Italy); S. Di Serego, A. Cimatti, Della Valle
(Observ. of Arcetri, Florence, Italy); F. Fiore, G.L. Israel, L. Stella
(Observ. of Monte Porzio, Rome, Italy); M. Vietri (Univ. Rome 3, I);
N. Kawai (RICHEN, Japan); D. Lazzati (IoA, Cambridge, UK); S. Ortolani
(Univ. of Padua, Italy); L. Pasquini (ESO, Germany); G. Ricker (MIT,
USA); E. Le Floch, P. Goldoni, F. Mirabel (CEA, F), H. Boehnhardt (on
behalf of the Melipal team, ESO, Paranal, Chile) report:
On 2002 April 8.164 we observed the optical counterpart of GRB 020405
reported by Price et al. (GCN 1326). The observations were performed
with the ESO VLT-3 (Melipal) telescope equipped with FORS1 with a V
filter in the imaging polarimetry mode. The transient source is clearly
detected and the acquisition image allowed to derive the Bessel V
magnitude of the transient, V=22.0 +/- 0.1, assuming V=18.5 and V=17.6
for the comparison USNO-A2.0 stars 0525-16813005 and 0525-16815468,
respectively, as reported in Palazzi et al. (GCN 1328).
Relative photometry between our V band observations of April 7.143
and 8.164 shows that the OT decayed by 0.60 +- 0.05 magnitudes, implying
a decay slope of 1.52 +- 0.12, also consistent with
the previous V mesurement by Palazzi et al (GCN 1328).
This message is citeable.
GCN Circular 1340
Subject
GRB 020405: Moderate-resolution spectroscopy
Date
2002-04-08T19:25:15Z (24 years ago)
From
Paul Price at RSAA, ANU at CIT <pap@srl.caltech.edu>
P.A. Price (Caltech), M. Pettini (Cambridge), N. Reddy, C. Steidel
and S.R. Kulkarni (Caltech) report on behalf of the REACT GRB
collaboration:
We have observed the afterglow of GRB 020405 (GCN #1326) with the
Keck II telescope + ESI. Observations consisted of 2x1800 sec exposures
in the eschellete mode. In this mode we are able to resolve the sky
lines, which is particularly important since at the reported redshift
of z = 0.695 (Masetti et al., GCN #1330) the [O II] line is coincident
with a strong atmospheric line. A preliminary reduction of the spectra
reveals emission lines of [O II], Hbeta, and [O III], at a mean redshift
of z = 0.6898 +/- 0.0005. In particular, we resolve the [O II] doublet
and thus we consider the redshift to be secure.
This message may be cited.
GCN Circular 1337
Subject
GRB020405: VLT optical observations
Date
2002-04-07T21:12:03Z (24 years ago)
From
Stefano Covino at Brera Astronomical Observatory <covino@merate.mi.astro.it>
S. Covino, G. Ghisellini, P. Saracco, G. Tagliaferri, F. Zerbi
(Observ. of Brera, Milan, Italy); S. Di Serego, A. Cimatti, Della Valle
(Observ. of Arcetri, Florence, Italy); F. Fiore, G.L. Israel, L. Stella
(Observ. of Monte Porzio, Rome, Italy); M. Vietri (Univ. Rome 3, I);
N. Kawai (RICHEN, Japan); D. Lazzati (IoA, Cambridge, UK); S. Ortolani
(Univ. of Padua, Italy); L. Pasquini (ESO, Germany); G. Ricker (MIT,
USA); E. Le Floch, P. Goldoni, F. Mirabel (CEA, F), H. Boehnhardt (on
behalf of the Melipal team, ESO, Paranal, Chile) report:
On 2002 April 7.14 we observed the optical counterpart of GRB 020405
reported by Price et al. (GCN 1326). The observations were performed
with the ESO VLT-3 (Melipal) telescope equipped with FORS1 with a V
filter in the imaging polarimetry mode. The transient source is clearly
detected and the acquisition image allowed to derive the Bessel V
magnitude of the transient, V=21.45 +/- 0.1, assuming V=18.5 and V=17.6
for the comparison USNO-A2.0 stars 0525-16813005 and 0525-16815468,
respectively, as reported in Palazzi et al. (GCN 1328).
This message is citeable.
GCN Circular 1336
Subject
Revised Photometry of the Optical Afterglow of GRB 020405
Date
2002-04-07T13:07:51Z (24 years ago)
From
Jens Hjorth at U.Copenhagen <jens@astro.ku.dk>
Revised Photometry of the Optical Afterglow of GRB 020405
J. Hjorth (U. Copenhagen) reports:
The calibration of the PSF photometry reported in GCN #1329 relied on a
misidentification of the USNO A2.0 star 0525_16813005 with 0525_16812476.
Calibration to 0525_16813005 yields R = 19.8 and B - R = 1.0 at April 6.21 UT,
consistent with the reports of Palazzi et al. (GCN #1328), Price et al.
(GCN #1333), and Gal-Yam et al. (GCN #1335). The systematic error in these
values is of the order of +- 0.3 mag. I apologize for the impact this error
may have had on follow-up strategies and thank Javier Gorosabel and Paul Price
for pointing out the problem.
Additional data taken with the DK1.5m between Apr 7.13 and Apr 7.37 confirm
the continued fading of the source. A careful analysis of these data is in
progress!
GCN Circular 1335
Subject
GRB020405: OT observations
Date
2002-04-07T12:26:43Z (24 years ago)
From
Eran Ofek at Tel Aviv U. <eran@wise1.tau.ac.il>
A. Gal-Yam, E. O. Ofek and Y. Lipkin (Wise Observatory, TAU) report:
We have observed the center of the error box of GRB 020405 using
the Wise Observatory 1m telescope + Tek CCD camera at 2002 Apr 05.95 UT.
Three 900 s R-band images were obtained. We identify the candidate OT
proposed by Price et al. (GCN 1326) for which we measure an R-band
magnitude of 18.8 +/- 0.14 mag, using the R=17.8 mag reference star from
Hjorth et al. (GCN 1329). Our measured value seems to agree better
with those of Price et al. (GCN 1333) than those of Hjorth et al.
(GCN 1329).
GCN Circular 1333
Subject
GRB 020405: Decay index
Date
2002-04-07T02:46:33Z (24 years ago)
From
Paul Price at RSAA, ANU at CIT <pap@srl.caltech.edu>
P.A. Price, B.P. Schmidt (RSAA, ANU) and T.S. Axelrod (Arizona)
report:
We have re-observed the afterglow candidate (GCN #1326