Spectroscopic Follow Up of Variable Quasars
Abstract
Outflows are a key facet of accretion physics, but one that is poorly understood. We are studying the time variability of broad absorption line (BAL) quasar outflows to constrain the location(s), dynamics and structure of these outflows, and evaluate their importance as a source of feedback for galaxy formation and (co-)evolution. We have used time-series photometry from SDSS Stripe 82 to confirm that the colours of BAL quasars are more variable than those of non-BAL quasars, due to trough variability. Photometry from Stripe 82 and proposed CFHT imaging can therefore be used to identify candidate BAL quasars with variable absorption troughs as well as previously non-BAL quasars with newly emerged absorption troughs. The same can be done for quasars previously observed spectroscopically in both the original SDSS and SDSS- III DR9. Spectroscopy is needed to confirm and study variability in detail, but photometric pre-selection of candidates makes for efficient spectroscopic followup. We therefore propose to use the Hale/5m or KPNO/4m for spectroscopic followup of quasars with candidate trough variability.
- Publication:
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NOAO Proposal
- Pub Date:
- August 2012
- Bibcode:
- 2012noao.prop..538R