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QAL. group. 1/15. The Central Engine of AGN in Xi’an (Oct. 17, 2006). Probing quasar outflows with intrinsic narrow absorption lines. T. Misawa, M. Eracleous, J. C. Charlton (PSU), R. Ganguly (University of Wyoming), D. Tytler, D. Kirkman, N. Suzuki, D. Lubin (UCSD). 2/15. Background.
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QAL group 1/15 The Central Engine of AGN in Xi’an (Oct. 17, 2006) Probing quasar outflows with intrinsic narrow absorption lines T. Misawa, M. Eracleous, J. C. Charlton (PSU), R. Ganguly (University of Wyoming), D. Tytler, D. Kirkman, N. Suzuki, D. Lubin (UCSD)
2/15 Background • A fraction of narrow quasar absorption lines (NALs) have • been thought to be produced by gas ejected from the quasar • central engines rather than by the intervening structures. • These lines (intrinsic absorption lines) are believed to arise in • a wind from the accretion disk around the super-massive • black hole. • Quasar absorption lines are historically classified into three • categories by their line widths:
3/15 Outline Introduction: How to separate intrinsic NALs from intervening NALs - Covering factor analysis - Time variability analysis PART I --- Statistical analysis: search for intrinsic absorption lines in spectra of 37 quasars (at z = 2-4) obtained with Keck to investigate global properties of wind material around the quasars (submitted to ApJ). → see a poster Ganguly et al. (P-ID088) for low-z targets PART II --- Monitoring project: monitoring the variability of an intrinsic NAL in the quasar HS1603+3820 with the Subaru telescope, which enables us to investigate the detailed structure of absorbers (1AJ, 1ApJ, and 1ApJ submitted).
Introduction → e.g., ISM, HVC in MW → e.g., DLA, LLS, metal lines → e.g., Lyα forest → e.g., BAL profile halo gas quasar (2) (3) (2) observer (4) intergalactic gas disk gas around quasar (1) Lyαforest BAL profile MW DLA metal lines Redshift 4/15 What produces NALs? There are several types of absorbers: (1) absorbers in our Galaxy (2) disk/halo-gas in intervening galaxies (3) the intergalactic gas (4) gas physically associated with the quasars Absorption lines in the spectra of quasars are produced whenever the line of sight to the quasars pass through clouds of gas. intervening intrinsic gas in our galaxy
Introduction R~45000 R~3000 5/15 How to identify intrinsic absorption lines With high-dispersion spectroscopy, individual intrinsic NALs have been resolved into narrower multiple components. Time variability of line profiles: e.g., depth, equivalent width, and line centroid, Cf within a few years in the absorber’s rest frame. (e.g., Hamann et al. 1997) (B) Gas motion across the line of sight (A) Change of ionization condition in absorbing gas absorber Covering factor analysis QSO Time variability analysis (e.g., Wampler et al. 1995)
Census 6/15 RESULTS: PART 1 - Census of intrinsic NALs - 150 NAL systems in 37 Keck/HIRES quasar spectra Class B (possible intrinsic) Class A (reliable intrinsic) Class C (intervening/unclassified) 28 class-A 11 class-B 111 class-C
Census 7/15 Fraction of intervening NALs associated (vej<5,000 km/s) non-associated (vej >5,000 km/s) Total C IV N V N/A Si IV C IV: 11-19% of all C IV NALs have partial coverage. Among “associated” NALs (AALs; within 5,000 km/s of the quasar emission redshift), 33% show partial coverage. N V: Because of the Lya forest, we were unable to study N V doublets with vej < -5,000 km/s. Of the associated N V NALs, 75% show partial coverage. Si IV: 14-18% of all Si IV NALs have partial coverage. None of them are associated NALs.
Census 0 1 3 3 2 17 4 3 10 4 8/15 Fraction of Quasars that have Intrinsic NALs NAL (~50%) BAL (~10-15%) Proga et al. (1998,1999,2000) Number of quasars that have 0-4 intrinsic NAL systems At least half of all quasars have one or more intrinsic NAL systems. - If we assume that NAL absorbers are in the region with opening angle of 60 degree from the axis, then they cover 50% of the total solid angle. - The model of Proga et al. (2000) shows that the column density of this region is too low (and IP is too high) to produce C IV NALs. Therefore, the NAL gas would be denser filaments embedded in the higher ionization gas.
Census 9/15 Ionization Conditions of Intrinsic NALs (1) Strong N V system Strong C IV system Strong (sometimes saturated) C IV and Lyα with weak/no N V Strong N V and weak C IV and Lyα(less than twice the N V EW) 28 C IV systems 11 N V systems
Census 10/15 Ionization Conditions of Intrinsic NALs (2) Lo-NAL Hi-NAL detected detected detected Not detecetd Not detected detected Not detected IP detected detected IP Not detected 16 NALs 23 NALs detected About 2% of quasars are LoBAL quasar (Sprayberry & Foltz 1992; Reichard et al. 2003). ~25% of quasars are LoNAL quasars
E F G H A B C D Monitoring Cf ~ 1.0 Cf < 1.0 Cf ~ 1.0 11/15 RESULTS: PART 2 Monitoring a quasar HS 1603+3820 E F G H A B C D System B System A
Monitoring 12/15 Time Variability Analysis C IV lines in HS1603+3820
Monitoring 13/15 Model Fittings
Monitoring 14/15 • No clear correlations are seen • between fit parameters • → inhomogeneous internal structure • All absorption components • changed in concert • → change of ionization condition Variable screening by another absorber.
Future Plans VLT+UVES archive data Chandra and XMM-Newton archive data we are now proposing to get additional spectra with Subaru and VLT. 15/15 Extend sample size and study of NAL demographics based on quasar properties (e.g., radio-loudness) monitor other NAL systems with more than one transition, and apply photoionization model to monitor ionization conditions. Investigate inner regions of the accretion disks, and compare our optical results.