Outflows in Emission and Outflows in Emission and Absorption: The SDSS PerspectiveAbsorption: The SDSS Perspective
Gordon Richards, John Hopkins University
With thanks to Pat Hall, Jon Trump, Tim Reichard, Sarah Gallagher, and others
OutlineOutline
• Evidence for outflows from emission linesEvidence for outflows from emission lines– CIV blueshiftsCIV blueshifts– Relationship between blueshifts and the Baldwin Effect Relationship between blueshifts and the Baldwin Effect
(which may, in fact, be the same phenomenon)(which may, in fact, be the same phenomenon)
• Clues to the nature of the wind from absorption linesClues to the nature of the wind from absorption lines– Emission line properties of BALQSOsEmission line properties of BALQSOs– NALs in BALsNALs in BALs
• Conclusions -- All quasars have winds/outflows, but Conclusions -- All quasars have winds/outflows, but the nature of the winds change as a function of their the nature of the winds change as a function of their SEDsSEDs
Emission Line BlueshiftsEmission Line Blueshifts
• Numerous papers (e.g. Tytler & Fan 1992, Marziani+ 1996) Numerous papers (e.g. Tytler & Fan 1992, Marziani+ 1996) confirm this result (and extend it to other emission lines, mostly confirm this result (and extend it to other emission lines, mostly high ionization [but Hhigh ionization [but H is redshifted]) is redshifted])
• Richards et al. (2002) study emission line shifts in a large sample Richards et al. (2002) study emission line shifts in a large sample of SDSS quasars, finding that CIV blueshifts are the norm, not the of SDSS quasars, finding that CIV blueshifts are the norm, not the exception, and argue that the blueshifts result from “missing” flux exception, and argue that the blueshifts result from “missing” flux in the red wingin the red wing
• Baskin & Laor (2004) summarize arguments for L/LBaskin & Laor (2004) summarize arguments for L/LEddEdd as the as the
driver (but we will not consider this further as it does not driver (but we will not consider this further as it does not [directly] relate to the structure of the wind)[directly] relate to the structure of the wind)
• Gaskell (1982), Wilkes (1984) Gaskell (1982), Wilkes (1984) find that some emission lines find that some emission lines (particularly CIV) are blueshifted (particularly CIV) are blueshifted with respect to the quasars’ systemic with respect to the quasars’ systemic redshiftredshift
Richards et al. 2002 SummaryRichards et al. 2002 Summary
• The blueshifts are not correlated with MThe blueshifts are not correlated with Mii (but this may be mis-(but this may be mis-leading if the shape of the SED or UV luminosity is the important quantity leading if the shape of the SED or UV luminosity is the important quantity to measure).to measure).
• The blueshift is not a bulk line shift, but rather a The blueshift is not a bulk line shift, but rather a reduction/suppression/obscuration of the red wing. reduction/suppression/obscuration of the red wing. This is not necessarily This is not necessarily meant to say that the red wing flux is absorbed, but simply that the process 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 may be more complex than is generally assumed. This may be important for masses determined from the FWHM of CIV and for metallicity for masses determined from the FWHM of CIV and for metallicity measurements.measurements.
• Blueshifts may be an orientation indicator. Blueshifts may be an orientation indicator. This need not be the This need not be the external orientation, but may reflect the opening angle of the wind (which external orientation, but may reflect the opening angle of the wind (which may depend on L/Lmay depend on L/LEddEdd).).
• CIV blueshifts are ubiquitous in radio-CIV blueshifts are ubiquitous in radio-quiet quasars (radio loud quasars quiet quasars (radio loud quasars having smaller [or zero] blueshift.having smaller [or zero] blueshift.• Large CIV blueshift quasars have Large CIV blueshift quasars have larger FWHM lines, but smaller larger FWHM lines, but smaller equivalent widths.equivalent widths.
CIV Blueshifts in SDSS QuasarsCIV 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.
CIV Blueshifts Not Just a WindCIV Blueshifts Not Just a WindSaying that this is due to a wind is an over simplification.
1) Mean maximum outflow velocity does not increase
2) Rather the peak is blueshifted
3) Equivalent width decreases
4) Bicones can produce redshifts as well as blueshifts depending on viewing angle relative to opening angle
R+02
Elvis00
The Baldwin Effect (BEff)The Baldwin Effect (BEff)
• There are notable exceptions (e.g. SiIV)There are notable exceptions (e.g. SiIV)
• The effect may be due to SED shape rather than luminosity The effect may be due to SED shape rather than luminosity (e.g., Binette ete al. 1989, Zheng & Malkan 1993, Korista et al. (e.g., Binette ete al. 1989, Zheng & Malkan 1993, Korista et al. 1998, etc.)1998, etc.)
• For example: the LFor example: the Luvuv - L - Lxx relationship (Avni & Tannanbaum relationship (Avni & Tannanbaum
1982, Wilkes et al. 1994, Green et al. 1995, Vignali et al. 2003, 1982, Wilkes et al. 1994, Green et al. 1995, Vignali et al. 2003, Strateva et al. 2005)Strateva et al. 2005)
• See Dietrich et al. 2002 for a recent reviewSee Dietrich et al. 2002 for a recent review
• Baldwin (1977) shows that more Baldwin (1977) shows that more luminous quasars have weaker CIV luminous quasars have weaker CIV emission linesemission lines
• Numerous papers confirm this effect and Numerous papers confirm this effect and extend it to other emission lines, generally extend it to other emission lines, generally high ionizationhigh ionization
BEff vs. BlueshiftsBEff vs. BlueshiftsThere are many similarities between the BEff and the CIV emission line blueshifts.• Weaker CIV lines
• Which lines show the effect
• SED/Luminosity dependence
• Velocity dependenceSuggests that the 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).
Blueshifts = Baldwin Effect IBlueshifts = 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)
Blueshifts = Baldwin Effect IIaBlueshifts = 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)
Blueshifts = Baldwin Effect IIbBlueshifts = Baldwin Effect IIbIt 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.
Blueshifts = Baldwin Effect IIIBlueshifts = Baldwin Effect III
Francis & Koratkar (1995) found that the Baldwin Effect is strongest in the the red wing of the CIV emission line.
CIV Blueshifts in CIV Blueshifts in SDSS QuasarsSDSS 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.
Blueshift/Color CompositesBlueshift/Color CompositesSiIV CIV HeII
CIV Blueshifts in CIV Blueshifts in SDSS QuasarsSDSS Quasars
X-ray strong quasars
X-ray weak quasars
Blueshifted quasars tend to be weaker X-ray sources.
CIV Blueshifts and X-ray CIV Blueshifts and X-ray AbsorptionAbsorption
Gallagher et al. 2004
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.
CIV Blueshifts in CIV Blueshifts in SDSS QuasarsSDSS 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.
BALQSO Emission Line PropertiesBALQSO 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.
1) 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.)
2) The BAL trough structure appears to be correlated with emission line (and SED) properties. See Turnshek (1988).
BALQSOs Have Large BlueshiftsBALQSOs Have Large BlueshiftsComposite 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
Red/Blue BALQSOsRed/Blue BALQSOs
Reichard et al. 2003
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.
Absorption Correlated w/ EmissionAbsorption Correlated w/ Emission
Fast drop-off
Rolling Hills
BALs with NALs?BALs with NALs?
BALQSOs can also have NALs. These quasars tend to have broad, but weak emission lines.
15% of Quasars are BALQSOs15% of Quasars are BALQSOs
1)1) BALQSOs are a separate class of quasars, BALQSOs are a separate class of quasars, amounting to 15% of the populationamounting to 15% of the population
2)2) All quasars are BALQSOs, but the BAL All quasars are BALQSOs, but the BAL covering fraction is 15%covering fraction is 15%
15% of Quasars are BALQSOs15% 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.
SummarySummaryThis is a BALQSO
This is a BALQSO -- probably a LoBAL
This is NOT a BALQSO
