ASCA and ROSAT Observations of NRAO 140 and IX Persei
Abstract
We report the results from observations of NRAO 140 carried out in the X-ray band using ROSAT and ASCA in 1992 and 1994. We find the source to be absorbed by an effective hydrogen column density of ~3 x 10^21^ atoms cm^-2^ during both epochs, consistent with the combined atomic and molecular column inferred from radio measurements along this line of sight through the Perseus cloud complex. We compare these results with previous X-ray absorption measurements and briefly comment upon the origin of the excess absorption which has been seen toward this source. We find the ASCA spectrum of NRAO 140 is well described by a power law of energy index α = 0.73 + 0.03 and also yields the tightest constraint to date on Fe K-shell emission, with 90% confidence upper limits of 38 and 31 eV for a narrow line at a rest frame energy of 6.4 and 6.7 keV respectively. This, along with a lack of hardening towards higher energies, suggests that either NRAO 140 is devoid of cold reprocessing material, the reprocessing material has a geometry in which the imprinted features are weak, and/or the X-ray emission is relativistically beamed towards us. We also report the detection of a serendipitous source in both the ASCA GIS and ROSAT fields of view. We identify this source as the binary star system IX Per and find its spectrum to be well fitted by a two- temperature Raymond-Smith plasma.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 1995
- DOI:
- 10.1086/175728
- Bibcode:
- 1995ApJ...445..660T
- Keywords:
-
- Data Reduction;
- Quasars;
- Radio Astronomy;
- Rosat Mission;
- X Ray Astronomy;
- X Ray Stars;
- Absorption Spectra;
- Active Galactic Nuclei;
- Energy Spectra;
- Imaging Spectrometers;
- Stellar Luminosity;
- Astrophysics;
- GALAXIES: QUASARS: INDIVIDUAL ALPHANUMERIC: NRAO 140;
- RADIATION MECHANISMS: NONTHERMAL;
- STARS: INDIVIDUAL CONSTELLATION NAME: IX PERSEI;
- X-RAYS: GALAXIES;
- X-RAYS: STARS