Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams -- Image credits

IAUC 8110: V838 Mon; 2003bg; GRB 030329

The following International Astronomical Union Circular may be linked-to from your own Web pages, but must not otherwise be redistributed (see these notes on the conditions under which circulars are made available on our WWW site).

Read IAUC 8109  SEARCH Read IAUC 8111

View IAUC 8110 in .dvi or .ps format.
IAUC number

                                                  Circular No. 8110
Central Bureau for Astronomical Telegrams
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
URL http://cfa-www.harvard.edu/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7440/7244/7444 (for emergency use only)

     M. Orio, Istituto Nazionale di Astrofisica, Torino, and
University of Wisconsin; S. G. Starrfield, Arizona State University;
and E. Tepedenlegliolu, University of Wisconsin, report that V838
Mon was observed with Chandra (+ ACIS-S) on Feb. 23 for 6800 s, and
it was not detected with a 3-sigma upper limit to the count rate of
approximately 0.04 count/s: "This translates into an upper limit to
the unabsorbed flux in the band 0.2-10 keV of F_x </= 6.5 x 10**-14
erg cm**-2 s**-1, assuming N_H = 4.76 x 10**21 cm**-2 [derived from
E(B-V) = 0.8 mag; Kimesweger et al. 2002, MNRAS 336, L43] and a
plasma emitting at temperature 1 keV, or F_x </= 4.5 x 10**-9 erg
cm**-2 s**-1, assuming instead a blackbody emitting with a
temperature of 30 eV.  Given a distance in the range 2000-6000 pc
(Bond et al. 2003, Nature, in press), the above upper limit to the
x-ray flux rules out that either the central source, or a wind from
it, emits x-ray luminosity at the level observed in symbiotic novae
a year after the outburst (see Muerset et al. 1997, A.Ap. 319, 201).
This is strong evidence against a nova-like thermonuclear runaway
as mechanism for the 2002 outburst of this object."

SUPERNOVA 2003bg IN MCG -05-10-15
     D. Pooley and W. H. G. Lewin, Massachusetts Institute of
Technology, on behalf of a larger collaboration, report the
detection of x-ray emission from SN 2003bg with the Chandra X-ray
Observatory.  A 50500-s ACIS-S3 observation on Mar. 24.49 UT
reveals a 560-count source (0.5-10 keV) at R.A. = 4h10m59s.42,
Decl. = -31o24'50".3 (equinox 2000.0; +/- 0".5 in R.A. and Decl.),
in close agreement with the optical position (cf. IAUC 8082).
Preliminary spectral analysis indicates much low-energy (< 1 keV)
emission, perhaps indicating little absorption.  A power-law fit
gives a photon index of 1.9, but the data are better represented by
hot plasma models (MEKAL models in XSPEC) and are equally well fit
by a two-component MEKAL model with solar elemental abundances
(kT_1 = 0.5 keV; kT_2 = 6.5 keV) or a single MEKAL plasma (kT = 5.7
keV) with significant overabundances of O, Ne, and Ni.  Both models
give an unabsorbed 0.5-10-keV luminosity of about 4 x 10**39 erg/s
(19.1 Mpc, H_0 = 70 km/s/Mpc).  A second Chandra observation is
planned in late May.  Further optical and radio observations are

GRB 030329
     Additional magnitudes from J. McGaha (cf. IAUC 8107):  Apr.
5.250 UT, R = 18.39; 5.252, V = 18.34; 5.255, B = 18.83; 5.257, I =

                      (C) Copyright 2003 CBAT
2003 April 8                   (8110)            Daniel W. E. Green

Read IAUC 8109  SEARCH Read IAUC 8111

View IAUC 8110 in .dvi or .ps format.

Our Web policy. Index to the CBAT/MPC/ICQ pages.

Valid HTML 4.01!