Outflows in Emission and Absorption: The SDSS Perspective

1. Outflows in Emission and Absorption: The SDSS Perspective Gordon Richards, John Hopkins University With thanks to Pat Hall, Jon Trump, Tim Reichard, Sarah Gallagher, and others

2. Outline • Evidence for outflows from emission lines • CIV blueshifts • Relationship between blueshifts and the Baldwin Effect (which may, in fact, be the same phenomenon) • Clues to the nature of the wind from absorption lines • Emission line properties of BALQSOs • NALs in BALs • Conclusions -- All quasars have winds/outflows, but the nature of the winds change as a function of their SEDs

3. Emission Line Blueshifts • Gaskell (1982), Wilkes (1984) find that some emission lines (particularly CIV) are blueshifted with respect to the quasars’ systemic redshift • Numerous papers (e.g. Tytler & Fan 1992, Marziani+ 1996) confirm this result (and extend it to other emission lines, mostly high ionization [but H is redshifted]) • Richards et al. (2002) study emission line shifts in a large sample of SDSS quasars, finding that CIV blueshifts are the norm, not the exception, and argue that the blueshifts result from “missing” flux in the red wing • Baskin & Laor (2004) summarize arguments for L/LEdd as the driver (but we will not consider this further as it does not [directly] relate to the structure of the wind)

4. Richards et al. 2002 Summary • CIV blueshifts are ubiquitous in radio-quiet quasars (radio loud quasars having smaller [or zero] blueshift. • Large CIV blueshift quasars have larger FWHM lines, but smaller equivalent widths. • The blueshifts are not correlated with Mi(but this may be mis-leading if the shape of the SED or UV luminosity is the important quantity to measure). • The blueshift is not a bulk line shift, but rather a reduction/suppression/obscuration of the red wing. This is not necessarily meant to say that the red wing flux is absorbed, but simply that the process may be more complex than is generally assumed. This may be important for masses determined from the FWHM of CIV and for metallicity measurements. • Blueshifts may be an orientation indicator. This need not be the external orientation, but may reflect the opening angle of the wind (which may depend on L/LEdd).

5. CIV Blueshifts in SDSS Quasars Blueshift of CIV emission line with respect to MgII for 12,700 SDSS quasars. N.B. If CIV blueshifts are an indicator of outflows, then virtually all quasars have them.

6. CIV Blueshifts Not Just a Wind Elvis00 R+02 Saying that this is due to a wind is an over simplification. Mean maximum outflow velocity does not increase Rather the peak is blueshifted Equivalent width decreases Bicones can produce redshifts as well as blueshifts depending on viewing angle relative to opening angle

7. The Baldwin Effect (BEff) • Baldwin (1977) shows that more luminous quasars have weaker CIV emission lines • Numerous papers confirm this effect and extend it to other emission lines, generally high ionization • There are notable exceptions (e.g. SiIV) • The effect may be due to SED shape rather than luminosity (e.g., Binette ete al. 1989, Zheng & Malkan 1993, Korista et al. 1998, etc.) • For example: the Luv - Lx relationship (Avni & Tannanbaum 1982, Wilkes et al. 1994, Green et al. 1995, Vignali et al. 2003, Strateva et al. 2005) • See Dietrich et al. 2002 for a recent review

8. BEff vs. Blueshifts There are many similarities between the BEff and the CIV emission line blueshifts. • Weaker CIV lines • Which lines show the effect • SED/Luminosity dependence • Velocity dependence Suggests thatthe Baldwin Effect and CIV Blueshifts are the same phenomenon. We just don’t normally realize it because the CIV redshift is usually taken to be systemic (and because luminosity effects can be hard to disentangle from SED effects).

9. Blueshifts = Baldwin Effect I Large blueshift quasars have larger FWHM CIV emission lines. The CIV lines are also much weaker. (See also Corbin 1990, Marziani+ 96)

10. Blueshifts = Baldwin Effect IIa In R02, we argued that the blueshifts are not a luminosity effect (in Mi), but that the quasars with blueshifts are bluer. It is likely that these relationships are driven not so much by luminosity, but by the SED (e.g. Zheng & Malkan 1993)

11. Blueshifts = Baldwin Effect IIb It has been long known (e.g., Avni & Tannanbaum 1982; Wilkes et al. 1994; Green et al. 1995) that more UV luminous quasars are (relatively) weaker X-ray sources (ox more negative). Vignali, Brandt & Scheneider (2003) and Strateva et al. (2005) have confirmed this correlation and characterized it for a large population of quasars. Given that the ionizing photons that produce CIV come from the far-UV/soft-X-ray, it seems unlikely that the Baldwin Effect/CIV blueshifts are independent of this fact.

12. Blueshifts = Baldwin Effect III Francis & Koratkar (1995) found that the Baldwin Effect is strongest in the the red wing of the CIV emission line.

13. CIV Blueshifts in SDSS Quasars Blueshifted quasars are bluer than average. But not all blue quasars have blueshifts. It may be important to further consider the colors in addition to blueshifts. Thus we make composite spectra for 3 blueshift/color combinations.

14. Blueshift/Color Composites SiIV CIV HeII

15. CIV Blueshifts in SDSS Quasars X-ray strong quasars X-ray weak quasars Blueshifted quasars tend to be weaker X-ray sources.

16. CIV Blueshifts and X-ray Absorption This is consistent with our results from Gallagher et al. (2004), where large blueshift objects (dots) were seen to show evidence for soft X-ray absorption. Gallagher et al. 2004

17. CIV Blueshifts in SDSS Quasars Radio-loud quasars tend to have small blueshifts. Comparison with de Vries, Becker & White (astro-ph/0510747) suggests that FRIIs may have smaller blueshifts than core dominated sources.

18. BALQSO Emission Line Properties We may be able to get an additional handle on the nature of winds using CIV blueshifts as there are correlations between BALQSOs and emission line features. Bona-fide BALQSOs appear have intrinsically blue optical colors and have weaker CIV lines that are also blueshifted. (Richards+02, Reichard+03, see also Corbin90.) The BAL trough structure appears to be correlated with emission line (and SED) properties. See Turnshek (1988).

19. BALQSOs Have Large Blueshifts Composite BALQSO spectra best match non-BALQSO composites with larger than average blueshifts. (Using the red wing of CIV, HeII and CIII] as the basis for comparison.) LoBALs appear to have even larger blueshifts than HiBALs. Richards et al. 2002

20. Red/Blue BALQSOs BALQSOs with redder power-law continua (after dust correction) have stronger emission lines and narrower, lower-velocity BAL troughs. In non-BALQSOs we see the same emission line trends with color. Reichard et al. 2003

21. Absorption Correlated w/ Emission Fast drop-off Rolling Hills

22. BALs with NALs? BALQSOs can also have NALs. These quasars tend to have broad, but weak emission lines.

23. 15% of Quasars are BALQSOs • BALQSOs are a separate class of quasars, amounting to 15% of the population • All quasars are BALQSOs, but the BAL covering fraction is 15%

24. 15% of Quasars are BALQSOs • All quasars have winds/outflows. • The structure of those outflows depends on the SED. • Bona-fide BAL troughs are found in quasars with certain SEDs (blue, large blueshift, X-ray weak). • All such quasars have BAL troughs (which are only seen along certain lines of sight). • The fraction of such quasars that exhibit BAL troughs is much larger than 15%. • 15% is simply the BALQSO fraction integrated over all SEDs.

25. Summary This is a BALQSO This is a BALQSO -- probably a LoBAL This is NOT a BALQSO