X-rays from the radio-quiet quasar PG 1407+265: relativistic jet or accretion disc emission?
Abstract
We present two XMM-Newton observations of the luminous (Lx > 1046ergs-1), radio-quiet quasar PG 1407+265, separated by 11 months. The data indicate two distinct states: a highly variable, bright state (first epoch); and a quiescent, low-flux one (second epoch). During the low-flux state the spectrum is consistent with a single, unabsorbed power law. However, during the brighter state a highly variable, steep component is statistically required. Contemporaneous ultraviolet data from the Optical Monitor allow an estimate of the optical-to-X-ray spectral index (αox), which appears typical of radio-quiet quasars during the low-flux state, but extremely flat during the high-flux state. The XMM-Newton data can be described as originating from a combination of jet and accretion disc processes, in which the (relativistic) X-ray jet only works intermittently. The scenario could help to describe some of the complexities seen in the broad-band spectral energy distribution of PG 1407+265, such as weak high-ionization emission lines, strong FeII, unbeamed continuum and the weak radio emission relative to the optical.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- January 2006
- DOI:
- 10.1111/j.1365-2966.2005.09780.x
- arXiv:
- arXiv:astro-ph/0510703
- Bibcode:
- 2006MNRAS.365..960G
- Keywords:
-
- galaxies: active;
- galaxies: jets;
- galaxies: nuclei;
- quasars: individual: PG 1407+265;
- X-rays: galaxies;
- Astrophysics
- E-Print:
- 9 pages, 8 figures. Accepted for publication in MNRAS. Correction made to reported aox value. No changes in conclusions