The Unusual Absorption Line System of PG 2302+029 -- Ejected or Intervening?
Abstract
A high-ionization broad absorption line system {C IV, N V, and O VI doublets; FWHM 3, 000 to 5, 000 km s^-1; z_rmabs=0.7} in the HST FOS UV spectrum of PG 2302+029 {z=1.052} has unprecedented properties. A distinct narrow line system {FWHM <250 km s^-1, z_abs=0.702} is also resolved within the broad system. If produced by material intrinsic to the quasar then the absorbing gas has been ejected from the quasar at more than sim56, 000 km s^-1. This extremely large ejection velocity as well as its ``detached'' nature {the reddest extent of the broad line absorption is more than 50, 000 km s^-1 from the quasar rest frame} would be unlike any known intrinsic absorber in QSOs. Alternatively, the broad and narrow systems could be produced by gas in a foreground cluster or super-cluster of galaxies. However, previous examples of such absorption have always included absorption by low-ionization species {e.g. Mg II, Si II}, which are not detected in the PG 2302+029 systems. We will undertake STIS and WFPC2 observations designed to help to identify the cause of this absorption system and allow us to determine whether the system is an extreme example of previously known classes of quasar absorption lines or represents an entirely new phenomenon.
- Publication:
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HST Proposal
- Pub Date:
- July 1997
- Bibcode:
- 1997hst..prop.7358J