Quasars, Black Holes & Host Galaxy Evolution Fred Hamann University of Florida (Quasar Metal Abundances)

Why quasars? Why high redshifts? Why metal abundances?  M BH   sph  SMBH growth linked to galaxy (spheroid) formation  Massive spheroids today have (mostly) old stellar pops.  Quasars mark the locations when and where the spheroids formed  Their metallicities trace the amount of star formation: When did the star formation occur during SMBH  galaxy evolution? How much star formation occurred before the visible quasar epoch?

Outline:  Metallicity diagnostics & results  Implications for SMBH  galaxy evolution  Significance of Fe/   Trends with z, L, L/L edd, Mass  Future Prospects

Broad Line Region (BLR) metallicities: Quasars have (broad) metal emission lines.  Prior star formation! Even for quasars at z > 6! Composite of z > 4 quasars (Hamann & Ferland 1999, Constantin et al. 2002) Shields 1976 Baldwin & Netzer 1978 Davidson & Netzer 1979 Uomoto 1984 ~ Solar metallicities +/- 1 dex Problem: As C/H increases, T gas decreases, and CIV/Ly   constant.

Shields (1976): Assume Nitrogen has secondary enrichment: N/O  O/H (as in galactic HII regions and stellar data) Use N III] 1750, N IV] 1486, etc., to avoid saturation issues (but weak and hard to measure) Hamann & Ferland (1992, 1993, 1999), Ferland et al. (1996): Include stronger UV lines: NV/CIV and NV/HeII  fainter quasars & larger samples Saturation/thermalization issued unavoidable Extensive photoionization simulations, with N/O  O/H

Hamann et al. (2002): Locally Optimally-emitting Cloud (LOC) model of BLR (Baldwin et al. 1995)  the BLR is stratified, a wide range in n H,  H coexist  not dependent on a particular choice Calculate line strengths & ratios for each n H,  H, Z Ionizing flux H density

Add line emission over each LOC grid  line ratios versus Z gas : Hamann et al. (2002) The metallicity dependence of these ratios is due mainly to N/O  O/H

Nagao et al. (2006): Include more lines, with sensitivities to n H,  H, temperature (Z gas )  less dependent on N lines and N/O  O/H  Find “best” solution for each quasar by tuning the weighted sums over LOC distrib. to match each quasar spectrum.

Nagao et al. (2006)  > 5000 SDSS quasars Dietrich et al. (2003)  Obtained spectra the old fashioned way.  Z gas  ~ 4-5 Z o

This quasar at z ~ 4.2 has many well- measured diagnostics We estimated: Z gas ~ 2 Z o Warner et al High redshift examples: Pentericci et al Z gas  Z o at redshift 6.28 based on NV/CIV, lower limit on NV/HeII

How much metal-rich gas? From what stellar population? LOC models suggest quasar M BLR ~ 1000 M o (Baldwin et al. 2003) But the amount of accretion over a quasar lifetime is  M BH If the BLR is continuously replenished by accretion, then the reservoir of metal-rich gas has mass: M gas  M BH ~ 10 9 M o Stellar mass needed to enrich this gas: M stars  few  10 9 M o  at least ~bulge-size stellar pops.

In our models, the NV ratios often suggest 1.5 to 2x higher Z gas than NIII]. Measurement error? (In “well-measured” - high EW - cases all the N lines agree.) (Dietrich et al. 2003)  Need independent checks

Narrow Line Region (NLR) metallicities: Groves et al. (2006): ~23,000 low-redshift Seyfert 2s from SDSS Visible emission-line ratios, e.g., [NII] 6584 Adopt: n H ~ 1000 cm 3, secondary N enrichment  All but 40 have Z gas  Z o  Typical values: Z gas ~ Z o Also: Storchi Bergmann & Pastoriza 1989 Storchi Bergmann et al. 1998, Nagao et al. 2002, Groves et al Much larger scales: 10 2 to 10 4 pc

Narrow Line Region (NLR) metallicities: Nagao et al. (2006): High-z quasar 2s and radio galaxies UV emission-line ratios (same lines at BLR) Adopt: n H ~ 10 2 or 10 5 cm 3, secondary N enrichment  Z gas = 0.2 to 5 Z o depending on n H

Associated Absorption Line (AAL) metallicities: Also posters: Nestor, Simon, Misawa, Ganguly Observed Wavelength AALs AALs appear in ~25% of quasars Probably form at a wide range of radii: ~10 to >10 4 pc A simpler analysis: Measure ionic column densities Apply ionization correction No assumptions about secondary N Foltz et al. 1986

Associated Absorption Line (AAL) metallicities:  Early results: Z gas  Z o and N/C  solar are typical (for bona fide near-quasar absorbers) Petitjean et al. 1994, Wampler et al. 1993, 1996, Savaglio et al. 1997, Hamann 1997, Tripp et al. 1995, 1997, Savage et al. 1998, …  Best/most recent: D’Odorico et al AAL quasars at redshifts 2.1 to 2.6 VLT/UVES spectra, resolution ~7 km/s 5 out of 6 have Z gas = 1 to 3 Z o  In progress: Leah Simon et al. 200x, poster n AAL quasars at redshifts at Keck, VLT, Magellan…

Other Indicators of star formation in quasar hosts: mm, sub-mm, CO, … ~30% of high-redshift, optically luminous quasars are ULIRGs based on mm and sub-mm (Cox et al. 2006, Beelen et al. 2006) Inferred SFRs ~ 1000 M o /yr Dust masses 10 8 to 10 9 M o  Enriched gas masses ~ to M o  Stellar pop. masses ~ few  to M o …formed prior to the quasar epoch. For example:  SF coincident with quasar  SF that preceded the quasar

Understanding Z gas  Z o near quasars: Galaxy Evolution Massive spheroids today are old and metal rich:  Z stars  ~ 1 to 3 Z o The gas that produced this population must have had Z gas >  Z stars  toward the end of the evolution. Central r e /8 in field ellipticals (Trager et al. 2000) Age (Gyr) log  Z stars 

Quasar Z’s are consistent with normal galactic chemical evolution… Friaca & Terlevich 1998 (and many others) if most of this star formation occurred before the quasar epoch, with  70% conversion of gas into stars.

Kauffmann & Haehnelt 2000, Granato et al In physically motivated models, e.g., to explain M BH   sph a major merger triggers a starburst and funnels gas toward the SMBH AGN (& SN) feedback halts the star formation… The visible/luminous quasar appears after the starburst, with central Z gas ~ 2-3 Z o Di Matteo et al. 2004, Hopkins et al. 2005, Springel et al obscured visible

Li et al In this GADGET-2 simulation, 8 galaxies merge to make an enormous starburst, then a quasar at z = 6.54

Li et al The total SFR reaches 10 4 M o /yr, creating a stellar mass of M o …before the quasar becomes bright/observable at z = 6.54 (final M BH  2  10 9 M o )

…leaving these metallicity distributions in gas and stars at the quasar epoch z =  Near solar on large scales, super-solar in dense pockets.  with Z gas ~ 2-3 Z o expected in the nucleus Li et al Di Matteo et al. 2004

solar Non-AGN data: Quasars metallicities are like massive SF galaxies: Z gas ~ 2-3 Z o e.g., in this SDSS sample of 53,000 at z ~ 0.1 (HII region emission-line diagnostics) Tremonti et al. 2004

Trends in the quasar data …can further constrain evolution models: Dietrich et al. (2003) 1) No significant trends with redshift, e.g., in these BLR studies Nagao et al. (2006) 

Trends in the quasar data: 2) More luminous quasars are more metal rich (based on BLR data). Nagao et al. (2006) Hamann & Ferland (1999)

Trends in the quasar data: 3) The fundamental trends are with Mass or L/L edd Shemmer et al. (2004) find a stronger relationship to L/L edd than to L or M BH, (based on 92 AGN with H  SMBH masses)  higher Z at earlier evolutionary stages?

Warner et al measured M BH (via CIV) in 578 AGN Create sub-samples to isolate trends with L and M BH … (Each sub-sample has ~150 quasars)

L  ergs/sM BH  10 9 M o Composite spectra for fixed L and M BH (Warner et al. 2006)  the underlying trend is mass-Z, possibly also driving the Baldwin Effect

These line ratios (metallicity) scale with M BH not Luminosity (L = constant)(M BH = constant) Mass  Metallicity is the main relation.

A physical explanation for the Baldwin Effect, driven by M BH : Metallicity increases with increasing M BH Korista et al. (1998), Warner et al. (2006) SED becomes softer with increasing M BH UV spectral index

All sources with both CIV and H  in Warner et al. sample CIV and H  yield similar M BH on average, e.g., in composites. with no systematic bias (Warner et al. 2003) Aside: M BH from CIV versus H 

Groves et al. (2006): Z in the NLR increases with galaxy mass (in their Seyfert 2 sample) 2x increase in O/H Galaxy mass  NLR mass  metallicity trend:

We might expect mass  metallicity in quasars based on the well-known mass  metallicity trend in galaxies: solar Lower mass galaxies expel their gas before it can be enriched to high metallicities. Tremonti et al. 2004Bender et al. 1993

Summary: Quasar environs are metal rich, Z gas  1-5, out to the highest redshifts. Enriched by at least bulge-size stellar pops. (  M o ), but maybe by the entire spheroid involved in M BH   sph High quasar metallicities require major star- forming episodes before the visible quasar epoch: major merger  ULIRG/starburst  transition object?  quasar Quasars in more massive hosts are more metal rich, …with an added dependence on L/L edd (age)? AALs and NLR lines at high redshifts Compare quasar Z’s to host galaxy properties (mass, age, Z stars, etc.) Transition objects (strong FIR, sub-mm) might be younger… Sort out trends with Mass or L/L edd Fe/  and other ratios… What’s next?

Hamann & Ferland 1999 Fe/  as a “clock”

Hamann & Ferland 1999

Understanding Z gas  Z o near quasars: 1)Massive/dense environments evolve quickly and are metal rich at all redshifts Quasars can uniquely probe galactic nuclei Log Metallicity Pettini 2001

Quasar metal abundances as probes of host galaxy evolution:  How “mature” are the surrounding stellar pops (at different redshifts)?  When did the first major star formation begin, relative to SMBH growth & quasar activity?  Does metallicity (star formation) correlate with L, M BH & L/Ledd ?  NLS1s, Baldwin Effect, broad line ratios…  AGN physics Dependence on L AGN, M BH & L/Ledd :

Dietrich et al. ( ) Warner, Hamann, & Dietrich ( ) 578 type I AGN measured at 950 < < 2050 Ǻ including 26 NLS1s Specifically targeted low L sources at high redshift

M BH = 1.4  10 6 M o ( ) FWHM(CIV) L (1450A) 1000 km/s ergs/s All sources with both CIV and H  measured (narrow H  components removed) There can be large differences between CIV and H  FWHMs in a given source, But in composites, CIV is ~  2 broader, consistent with reverberation and ~2x smaller R BLR + Peterson & Wandel (2000) Kaspi et al. (2000) Vestergaard (2002,04)

-26 A B C

A B C

Rest Wavelength Rest Wavelength Composite Spectra Sorted by SMBH massSorted by Luminosity Baldwin Effect plus changing NV line ratios 0

Fit the lines to deblend & measure line ratios

NV and possibly NIII] line ratios increase with M BH Log Z/Zo Log Z/Zo ?

Metallicity, based on N/O  O/H (Hamann & Ferland 1999, Hamann et al. 2001), is above solar and increases with M BH NV and possibly NIII] line ratios increase with M BH Log Z/Zo Log Z/Zo ?

AGN metallicity, from average of several Nitrogen line ratios......is above solar, and increases with both M BH and L. Log Z/Zo

 How “mature” are the surrounding stellar pops (at different redshifts)?  When did the first major star formation begin, relative to SMBH growth & quasar activity? High metallicities (even at the highest redshifts, Dietrich et al )  substantial conversion of gas  stars (>70% in simple closed box with “normal” galactic IMF) Major star formation before bright/visible AGN phase, accompanying SMBH growth (Dietrich & Hamann poster, and 2004). Stellar pop. masses > 10 4 to 10 5 M o (>3x M BLR ) (Baldwin et al. 2003) probably > M BH (>10 9 M o )

 Does metallicity (star formation) correlate with L, M BH ? Yes. How can we understand this? More massive galaxies produce:  more massive SMBHs  more luminous AGN  higher metallicities (in their cores)  The fundamental relationship “should” be mass-metallicity. How can we test this?

Log Z/Zo M BH and L correlate with each other (in this analysis), so: Create new composites to examine: a range in M BH at constant L, a range in L at constant M BH... Also spans range in LAlso spans range in M BH

Friaca & Terlevich 1998

 What about L/Ledd, NLS1s, …? Shemmer & Netzer (2002) noted higher NV/CIV in NLS1s, suggesting higher metallicities, for a given L.  Let’s look for trends with L/Ledd

L/Ledd = 1.6 ( ) FWHM(CIV) L 1000 km/s ergs/s  L Ledd

Distribution of derived L/Ledd values

Composite spectra sorted by L/Ledd. Note: constant peak heights constant line ratios

Log Z/Zo AGN metallicity from average of several Nitrogen line ratios... ▲ = NLS1s...shows no trend with L/Ledd. NLS1s may be slightly metal- rich for their L & M BH but not compared to high L quasars.

One last test: Examine composites spanning a range in L/Ledd at L = constant, M BH = constant.

L  3 x ergs/s Ledd  M BH  3 x 10 8 M o M BH L constant peak heights constant NV line ratios changing peak heights and NV line ratios Z

Conclusions:  Luminous, high M BH quasars are metal-rich (see also AALs), even at the highest redshifts,  substantial star formation before bright/visible AGN phase (during SMBH growth).  Nitrogen line ratios (metallicities) correlate strongly with M BH not with L or L/Ledd (AGN physics), probably tied to galactic mass-metallicity relation.  Enriching stellar populations probably have masses > M BH  very rare major starbursts beginning at z > 8.  NLS1s may be slightly more metal-rich for given L, M BH Based on CIV

Metallicity, based on N/O  O/H (Hamann & Ferland 1999, Hamann et al. 2001), is above solar and increases with M BH NV and possibly NIII] line ratios increase with M BH Log Z/Zo Log Z/Zo ?

Intrinsic Quasar NALs Hamann et al. (1997) Time variable, partial covering, broad & smooth troughs...

Discrete blobs. C f (v)  1. More accurate N i & abundances. ( Z  Z 0 ) Not discrete blobs. C f (v) < 1. Complex  (x,y) at each velocity. Analyze point by point in v. Use more lines, assume relative abundances of similar ions,  more constraints. Derive (limits on) N i (x) at each v. “Broad” AALs: Narrow AALs: