Red Parkes quasars: Evidence for soft X-ray absorption


Autoria(s): Masci, F. J.; Drinkwater, M. J.; Webster, R. L.
Data(s)

10/01/1999

Resumo

The Parkes Half-Jansky Flat-Spectrum Sample contains a large number of sources with unusually red optical-to-near-infrared (NIR) continua. If this is to be interpreted as extinction by dust in the line of sight, then associated material might also give rise to absorption in the soft X-ray regime. This hypothesis is tested using broadband (0.1-2.4 keV) data from the ROSAT All-Sky Survey. Significant (>3 sigma confidence level) correlations between the optical (and NIR)-to-soft X-ray continuum slope and optical extinction are found in the data, consistent with absorption by material with metallicity and a range in the gas-to-dust ratio as observed in the local ISM. Under this simple model, the soft X-rays are absorbed at a level consistent with the range of extinctions (0 < A(V) < 6 mag) implied by the observed optical reddening. Excess X-ray absorption by warm (ionized) gas, (i.e., a warm absorber) is not required by the data.

Identificador

http://espace.library.uq.edu.au/view/UQ:35432/UQ35432_OA.pdf

http://espace.library.uq.edu.au/view/UQ:35432

Idioma(s)

eng

Publicador

University of Chicago Press

Palavras-Chave #Astronomy & Astrophysics #Dust, Extinction #Ism #Quasars #X-rays #Magellanic Cloud #Optically Quiet #Dust #Spectra #Search
Tipo

Journal Article