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R. Smith

Publications and source records attributed to R. Smith.

146 records · Page 9Linked to original sources
arXiv2001

A first look at cataclysmic variable stars from the 2dF QSO survey

The 2dF QSO survey is a spectroscopic survey of 48,000 point-sources selected by colour with magnitudes in the range 18.35 < B < 20.95. Amongst QSOs, white dwarfs, narrow-line galaxies and other objects are some cataclysmic variables (CVs). This survey should be sensitive to intrinsically faint CVs. In the standard picture of CV evolution, these form the majority of the CV population. We present the spectra of 6 CVs from this survey. Four have the spectra of dwarf novae and two are magnetic CVs. We present evidence that suggests that the dwarf novae have period P < 2 h and are indeed intrinsically less luminous than average. However, it is not clear yet whether these systems are present in the large numbers predicted.

astro-ph↗
arXiv2001

A New ASCA and ROSAT Study of the Supernova Remnant: G272.2-3.2

G272.2-3.2 is a supernova remnant (SNR) characterized by an apparent centrally brightened X-ray morphology and thermally dominated X-ray emission. Because of this combination of Sedov-type (thermal emission) and non-Sedov type (non-shell like morphology) features, the remnant is classified as a ``thermal composite'' SNR. This class of remnant is still poorly understood due in part to the difficulties in modeling accurately all the physical conditions which shape the emission morphology. In this paper we present a combined analysis of data from the ASCA and ROSAT satellites coupled with previous results at other wavelengths. We find that the X-ray emission from G272.2-3.2 is best described by a non-equilibrium ionization (NEI) model with a temperature around 0.70 keV, an ionization timescale of 3200 cm^-3 yr and a relatively high column density (NH about 10^22 atoms/cm^2). We look into the possible explanations for the apparent morphology of G272.2-3.2 using several models (among which both cloud evaporation and thermal conduction models). For each of the models considered we examine all the implications on the evolution of G272.2-3.2.

astro-ph↗