Transcript Line vs Continuum Correlations Joe Shields Ohio University

Line vs Continuum Correlations
Joe Shields
Ohio University
Baldwin (1977)
The “Baldwin Effect” - Carswell & Smith (1979)
• Negative correlation between luminosity and line equivalent width
QSO spectra as function of
luminosity
(Dietrich et al. 2002)
Log EW 
Log L(line) 
Baldwin Effect
Log L(continuum) 
Log L(continuum) 
Baldwin Effect - Why Do We Care?
• Originally cosmology
• Early pattern emerging out of chaos of phenomenology
• Indicator of broad-line region/accretion physics
30 years later:
• Still interesting for BLR physics
(see Baldwin 1999 for cosmology)
• Much better data
• Context has grown (PCA, EV1, black hole masses, L/Ledd, etc.)
• EWs easy to measure
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Multiple Baldwin Effects ?
• Ensemble (“global”): single-epoch observations of multiple QSOs
• Intrinsic: multi-epoch observations of a single, variable AGN
• Broad lines
• Narrow lines
• X-ray (Fe K)
• WR stars??
• Novae??
Ensemble Baldwin Effect: what do we know?
UV/optical Broad Lines:
1)
It exists
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Formerly controversial
Lots of scatter common
Need sufficient range of L
Kinney et al. 1990
Ensemble Baldwin Effect: what do we know?
2)
Different slope for different lines
• Steeper slope for higher ionization lines
Dietrich et al. 2002
NV 1240 is an exception
Ensemble Baldwin Effect: lines of special interest
NV 1240 :
a)
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Most studies show no BE
Probable explanation: metallicity effect
N/H  Z2, higher Z goes with higher L (Hamann et al.)
Different behavior for NIII] 1750, NIV] 1486 (but weak lines)
H 4861 :
b)
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Recent studies show weak, inverse trend (negative BE)
Important for use of Balmer lines as tracer of luminosity
(e.g., Greene & Ho 2005, X.B. Wu talk)
EW  L0.2
EW  L0.1
(2dF, Croom et al. 2002)
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
(SDSS, Greene & Ho 2005)
Ensemble Baldwin Effect: explanations
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Luminosity-dependent covering factor/ionization parameter
(e.g. Mushotzky & Ferland 1984)
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Luminosity-dependent continuum shape
(e.g. Netzer et al. 1992, Korista et al. 1998)
Another fundamental parameter correlated with luminosity? E.g.
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redshift
L/Ledd
MBH
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Ensemble Baldwin Effect: L vs. z
Observational Problem:
L strongly correlated with z in most samples
(LBQS, Green et al. 2001)
Log (z)
Solution: fill in L-z plane
(Dietrich et al. 2002)
Ensemble Baldwin Effect: L vs. z
Bottom line:
z dependence weak compared to L
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
(Dietrich et al. 2002)
Ensemble Baldwin Effect: L vs. L/LEdd
LEdd: derive from MBH based on linewidth, L
BQS: Baskin & Laor 2004
(also Bachev et al. 2004)
 Tighter correlation with L/LEdd
Ensemble Baldwin Effect: L vs. L/LEdd
Results for H: Netzer et al. 2004
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Baldwin Effect in H ??
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Log EW
Ensemble Baldwin Effect: L vs. L/LEdd
Warner et al. 2004
Further correlations with L/LEdd
Ensemble Baldwin Effect: a function of L or …
Log L/LEdd
Caution: L, L/Ledd, MBH often highly correlated
Log L
Warner et al. 2004
Ensemble Baldwin Effect: L/LEdd vs MBH
Warner et al., submitted
 Stronger correlation with MBH
Ensemble Baldwin Effect: L vs MBH
Warner et al., submitted
 Stronger correlation with MBH
Ensemble Baldwin Effect and PCA Results
Shang et al. (2003):
• SPC1 mostly responsible for BE,
linked to L
SPC3 linked to Boroson & Green
EV1  L/LEdd or MBH
Shang et al. 2003
Narrow-Line Seyfert 1s and the Baldwin Effect
• Believed to be extreme EV1 or L/LEdd objects
Osmer, Porter,
& Green (1994)
Constantin & Shields (2003)
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Baldwin Effect in NLS1s
UV Baldwin Effect
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seen in NLS1s
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Offset to smaller EWs
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Points: NLS1 sample
Lines: Dietrich QSOs
(Leighly & Moore 2004)
(H shows negative trend also in NLS1s: Zhou et al. 2006)
Is BE more uniform in L/LEdd ?
Ensemble Baldwin Effect: L vs. L/LEdd
Log EW
Triangles: NLS1 average
Warner et al. 2004
 Additional parameter involved
Intrinsic Baldwin Effect
Example: NGC 4151 (Kong et al. 2006)
Intrinsic vs Ensemble Baldwin Effect
Kinney et al. (1990)
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Intrinsic Baldwin Effect: what do we know?
1)
Steeper than ensemble BE
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2)
Causes may be quite different
Curvature seen
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3)
Tighter relation seen if lag removed (e.g., Pogge & Peterson 1992)
(Lag is itself a function of L)
Consistent with photoionization theory
(Korista, Goad, Cackett, Horne, Knigge, …)
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Luminosity-dependent response a diagnostic tool for BLR
Intrinsic Baldwin Effect: what do we know?
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Some evidence of ionization-dependent slope
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e.g. CIV steeper than Ly
FeII:

Mixed results for slope (optical), e.g. NGC 5548 (Vestergaard &
Peterson 2005), NGC 4051 (= NLS1; Wang et al. 2005)
• FeII does respond to continuum photon excitation
• Measuring FeII is hard!
Wang et al. 2005
The Baldwin Effect in Narrow Lines
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Detection claimed in several studies, esp. [O III] 5007
[NeV]
MB
(Also IR: Keremedjev & Hao)
[OIII]
2dF: Croom et al. 2002
[OII]
[NeIII]
The Baldwin Effect in Narrow Lines
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Netzer et al. 2004
Popular explanation: high L NLR reaches limiting size = galaxy size
Implications for detection of Type II QSOs (e.g. Netzer et al. 2006)
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Weak lines  harder to find
Implications for star formation and detection via nebular lines? (cf. Ho 2005: weak [OII])
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Star formation suppressed? Or confined to dense regions with low filling factor?
X-Ray Baldwin Effect: Fe K (Iwasawa & Taniguchi 1993)
1)
Broad Fe K (Nandra 1997)
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Probable origin: “reflection” from accretion disk
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Models: luminosity-dependent ionization of disk (Nandra,
Nayakshin), and gravitational light-bending (Miniutti & Fabian 2004)
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Questions regarding broad component measurements
2)
Narrow Fe K (e.g. Page et al. 2004)
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Probable origin: reflection from outer disk or torus
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Model: luminosity dependent covering factor (receding torus)
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Due primarily to radio-loud sources with extra continuum
component? (Jiang et al. 2006)
Summary
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Baldwin Effect still significant for understanding AGN structure, physics
Seen in broad and narrow lines
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BE calibration useful when shifting between measures of luminosity
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Correlation with L may trace fundamental correlation(s)
with MBH, L/Ledd, … no consensus yet?
Some disagreement regarding PCA connection
NLS1s outliers
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Existence of X-ray Baldwin Effect uncertain
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Sample details still very important
Lots of progress, still work to do!