The ultraviolet spectrum of the high redshift QSO B2 1225 + 31

Abstract

view Abstract Citations (16) References (32) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The ultraviolet spectrum of the high redshift QSO B2 1225+31. Snijders, M. A. J. ; Pettini, M. ; Boksenberg, A. Abstract We present low-resolution, near-ultraviolet observations of the bright (V=15.87), high redshift (Zem ≍ 2.2) QSO B2 1225+31, obtained with the IUE long wavelength camera. These spectra provide an important extension to the large body of optical and radio work carried out on this object. The QSO continuum in the ultraviolet agrees well with the extrapolated visible flux, and we find no evidence in the ultraviolet and optical data available of variations in the magnitude of the source over the past few years. The QSO exhibits a rich absorption spectrum consisting of many strong lines (as in the visible shortward of the Lα emission line) which, however, are mostly blended at the present resolution, and a deep Lyman discontinuity near Zabs = 1.795, the redshift of the richest absorption complex identified in the optical range. In contrast, we detect no absorption attributable to gas at or near the emission redshift. Unless all the features in the IUE spectrum are blends, the strengths of the Lyman lines at Zabs = 1.795 point to the existence of substantial column densities of metal-poor gas, which is close in redshift to the metal-rich material giving rise to the most prominent visible lines. The H I column densities implied exceed by orders of magnitude those typical of the intergalactic clouds of primordial material thought to be responsible for the "Lα only" class of QSO absorption systems and may be indicative of a region similar to the extensive H I halos detected at 21 cm around many spiral galaxies. The possible detection of strong O VI absorption at Zabs = 1.795 is consistent with the conclusion of earlier optical work that this complex system is most likely formed in an intervening galactic halo. Publication: The Astrophysical Journal Pub Date: April 1981 DOI: 10.1086/158817 Bibcode: 1981ApJ...245..386S Keywords: Intergalactic Media; Quasars; Ultraviolet Spectra; Absorption Spectra; Galactic Structure; Iue; Lyman Alpha Radiation; Red Shift; Astronomy full text sources ADS | data products SIMBAD (1) NED (1) MAST (1)