DETECTION OF Ne VIII IN AN INTERVENING MULTIPHASE ABSORPTION SYSTEM TOWARD 3C 263

Journal Article · Sun Sep 20 04:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/703/1/74· OSTI ID:21372035

Narayanan, Anand; Wakker, Bart P

We report the detection of Ne VIII in an intervening multiphase absorption line system at z = 0.32566 in the Far Ultraviolet Spectroscopic Explorer spectrum of the quasar 3C 263 (z{sub em} = 0.646). The Ne VIII lambda770 A detection has a 3.9sigma significance. At the same velocity, we also find absorption lines from C IV, O III, O IV, and N IV. The line parameter measurements yield log [N(Ne VIII) cm{sup -2}] = 13.98{sup +0.10}{sub -0.13} and b = 49.8 +- 5.5 km s{sup -1}. We find that the ionization mechanism in the gas phase giving rise to the Ne VIII absorption is inconsistent with photoionization. The absorber has a multiphase structure, with the intermediate ions produced in cool photoionized gas and the Ne VIII most likely in a warm collisionally ionized medium in the temperature range (0.5-1.0) x 10{sup 6} K. This is the second ever detection of an intervening Ne VIII absorption system. Its properties resemble the previous Ne VIII absorber reported by Savage and colleagues. Direct observations of H I and O VI are needed to better constrain the physical conditions in the collisionally ionized gas phase of this absorber.

• OSTI ID: 21372035
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 703; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABSORPTION
COSMIC RADIO SOURCES
COSMOLOGY
ELECTROMAGNETIC RADIATION
FAR ULTRAVIOLET RADIATION
IONIZATION
PHOTOIONIZATION
QUASARS
RADIATIONS
SORPTION
SPECTRA
TEMPERATURE RANGE
TEMPERATURE RANGE OVER 4000 K
ULTRAVIOLET RADIATION