Тема: Вспыхнула RS Oph!!!!

[ctac]

 
--------------------------------------------------------------------------------
RS OPHIUCHI
--------------------------------------------------------------------------------
 

     T. J. O'Brien, T. W. B. Muxlow, S. T. Garrington, and R. J.
Davis, Jodrell Bank Observatory, University of Manchester; S. P. S.
Eyres, University of Central Lancashire; M. F. Bode, Liverpool John
Moores University; R. W. Porcas, Max-Planck-Institut fuer
Radioastronomie, Bonn; and A. Evans, Keele University, report that
5- and 6-cm MERLIN imaging has unambiguously resolved the expanding
radio source associated with the current outburst of RS Oph.  An
image taken on Mar. 2 at 5 cm is consistent with a radio source of
flux density 40  2 mJy, extended east-west.  Another image taken
on Mar. 6 at 6 cm shows a similar total flux density, but the
source has expanded sufficiently to enable some simple modelling of
the underlying structure.  Again the source is unambiguously
resolved east-west; careful imaging suggests that the source could
be either a double or triple structure.  Although it is difficult
to distinguish these from a single extended source, the more
complex models suggest that there is one main component of 30 mJy
with another 10 mJy distributed either in a second component to the
east or in two components, 60 mas apart, straddling the bright
central source --- the easterly being brighter than its western
counterpart.  This structure is very similar to that seen in an
image taken with the European VLBI Network 77 days after the 1985
outburst (Taylor et al. 1989, MNRAS 237, 81).  Assuming the three-
component structure to be correct and a distance to RS Oph of 1600
pc, these positions imply (symmetric) expansion velocities in the
plane of the sky of around 4000 km/s.  This is similar to the
highest velocities seen in optical spectroscopy (cf. CBET 403).
VLBA imaging on Feb. 26 and EVN imaging on Mar. 5/6 are awaiting
correlation.  Further VLBI imaging is being scheduled.

2006 March 8                   (8684)

[ctac]

--------------------------------------------------------------------------------
RS OPHIUCHI
--------------------------------------------------------------------------------
 

     G. C. Anupama, Indian Institute of Astrophysics, Bangalore;
and N. G. Kantharia, National Center for Radio Astrophysics, Pune,
report the low-frequency radio detection of the current outburst of
the recurrent nova RS Oph (cf. IAUC 8671) using the Giant Metrewave
Radio Telescope (GMRT), at the following flux densities:  Feb.
24.12 UT, 49.5 +/- 0.5 mJy at 23.3 cm; Mar. 2.04, 55.4 +/- 2.8 mJy
at 28.3 cm, 50.0 +/- 0.8 mJy at 23.3 cm, and 56.8 +/- 0.3 mJy at
21.6 cm; Mar. 5.09, 48.4 +/- 2.0 mJy at 49.2 cm.  This is the first
detection of the nova at wavelengths longer than 21 cm.  Further
GMRT observations at low frequencies are underway.

2006 March 13                  (8687)   

[ctac]

 А RS уже достигла 9 зв. вел.:

 
--------------------------------------------------------------------------------
RS OPHIUCHI
--------------------------------------------------------------------------------
 

     T. J. O'Brien, T. W. B. Muxlow, S. T. Garrington, and R. J.
Davis, Jodrell Bank Observatory, University of Manchester; R. W.
Porcas, Max-Planck-Institut fuer Radioastronomie, Bonn; M. F. Bode,
Liverpool John Moores University; S. P. S. Eyres, University of
Central Lancashire; and A. Evans, Keele University, write that 6-cm
radio observations made with the Very Long Baseline Array on Feb.
26 show radio emission from RS Oph in the form of a ring of
diameter approximately 18 mas, consistent with the size of the
single circular component fitted to the MERLIN imaging reported on
IAUC 8684.  The ring appears almost circular, clumpy, significantly
brighter on its eastern side, and with some evidence for a central
point source.  At a distance of 1600 pc, the diameter of the ring
is 29 AU and, assuming that it has expanded uniformly since
outburst, its expansion velocity is about 1800 km/s.  O'Brien et al.
suggest that this ring of radio emission may be identified with a
shock wave expanding through the red-giant wind following the nova
explosion, also resulting in the x-ray emission reported on IAUCs
8675, 8677, and 8683.  VLBA observations are continuing.
     Visual magnitude estimates, reported in part by E. Waagen,
AAVSO:  Feb. 17.249 UT, 6.5 (C. Labordena, Castellon, Spain);
21.847, 7.4 (A. Pearce, Nedlands, W. Australia); 26.180, 7.9 (B.
Granslo, Fjellhamar, Norway); Mar. 2.163, 8.1 (C. Otten, Kinrooi,
Belgium); 5.139, 8.2 (G. Mavrofridis, Nikea, Greece); 13.183, 8.9
(E. Muyllaert, Oostende, Belgium).

2006 March 16                  (8688)