Intrinsic Absorption in Quasars: BALs & NALs Jonathan Trump February 11, 2007

Quasar Absorption Lines Intrinsic –Caused by material in the AGN engine itself Host –From gas in the host galaxy Intervening –From an intervening galaxy This all has nothing to do with Type 2 AGN: we’re talking about absorption lines by diffuse gas, not global obscuration of the BLR by lots of dust!

Why Should We Care? Dynamics –Mechanism for losing angular momentum? –Accretion disk as power source for winds –Effects on host? Composition –Densities –Abundances Unified Model –Evolution? Orientation?

Broad Absorption Line Quasars from Trump et al. 2006

Broad absorption –Typically >1000 km/s –Up to ~20,000 km/s Blueshifted from emission line –Typically few thousand km/s (~0.01c) –Up to ~60,000 km/s (0.2c) Outflowing gas “wind” –High velocity dispersion –High velocity Broad Absorption Line Quasars

The Zoo of BAL types from Reichard et al. 2003

High-Ionization BALs –CIV 1550 Å, also SiIV, NV, Lyα –~15% of quasars Low-Ionization BALs –MgII 2800 Å, also Al II, Al III –~1-2% of quasars FeLoBALs –FeII or FeIII (widespread) –<0.1% of quasars Rarer objects: absorption in He, Balmer lines… Broad Absorption Line Quasars

FeLoBALs (they’re weird) from Trump et al. 2006

FeLoBALs (they’re weird) For more about FeLoBALs, see Hall et al. 2002, ApJ, 141, 267 from Hall et al. 2007

Characterizing BALs Balnicity Index (BI) –Weymann et al –Limits width, min/max blueshift, depth Absorption Index (AI) –Hall et al –Less limiting than BI, includes mini-BALs Characterization limited by S/N of spectra BALQSOs are red, and LoBALs are redder BALQSO fraction –Underestimated by all surveys: fainter, redder, obscured in X-rays Typically saturated, but with partial coverage     km/s km/s 0 '1dvCvf

What Causes BALs? Evolution –Young quasars in a dusty cocoon –Especially considered for LoBALs Orientation –Disk-driven wind in all quasars –Only visible in BALs because of orientation –Supporting evidence: Increased trough velocity with luminosity (Trump et al. 2006) –See models by Murray & Chiang 1998, Proga et al. 2000, etc.

from Elvis 2000

BALQSOs in Radio LBQS (Weymann et al. 1991): surprising lack of radio-loud BALQSOs SDSS (Reichard et al. 2003): same findings… –10% of quasars are radio-loud, but only a few percent of BALQSOs are radio-loud Supports orientation

BALQSOs in X-rays From Brandt et al More UV absorption -> weaker in soft X-rays

BALQSOs in X-rays weaker X-rays - > harder spectrum Absorbed in soft X-rays only Gallagher et al. 2006

BALQSOs in IR If BALQSOs are in a dusty cocoon, we’d expect stronger IR emission –Not the case! Spitzer survey of Gallagher et al find similar properties to normal QSOs Occasionally, some narrow absorption in IR

BALs from Orientation Different absorption mechanisms originate at different scales from the central engine from Gallagher & Everett 2007

Narrow Absorption Lines from Narayanan et al from Wise et al. 2004

Narrow Absorption Lines In >20% of all quasars (Wise et al. 2004), but hard to ID because of S/N & host/intervening lines Variability –Variable on the order of ~1 yr –Implies scales of <100 pc from the central source –> Intrinsic! –Really, the only way to determine intrinsic from host/intervening… but time-consuming

BALs & NALs: In Summary BALs: big, broad, blueshifted absorption –High velocities & velocity dispersions require AGN engine NALs: narrow, blueshifted absorption –High velocities & variability require AGN engine Typically weaker in X-rays, radio Mid-IR “normal” Probably caused by orientation –Disk-driven winds –But LoBALs are tougher to explain…

BALs from Orientation from Gallagher & Everett 2007