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AGN in the VVDS (Bongiorno, Gavignaud, Zamorani et al.) 1.What has been done: main results on Type 1 AGN evolution and accretion properties of faint AGN.

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Presentation on theme: "AGN in the VVDS (Bongiorno, Gavignaud, Zamorani et al.) 1.What has been done: main results on Type 1 AGN evolution and accretion properties of faint AGN."— Presentation transcript:

1 AGN in the VVDS (Bongiorno, Gavignaud, Zamorani et al.) 1.What has been done: main results on Type 1 AGN evolution and accretion properties of faint AGN 2.Work in progress : AGN – Host galaxies: M BH – stellar mass relation at z > 1 3. Still to be done (with the data at hands) : Type II AGN : evolution + fraction of AGN as a function of stellar mass, color etc.

2 Part1: The VVDS type-1 AGN Sample: Selection Pure magnitude limited sample I AB band Free of morphological or color selection biases Epoch 1 Sample: 130 BLAGN Optically selected ONLY Optically selected ONLY on the basis of their SPECTRA: on the basis of their SPECTRA: At least ONE broad line At least ONE broad line Wide sub-sample (I AB  22.5) Deep sub-sample (I AB  24.0) 56 AGN 74 AGN The VVDS type-1 AGN SAMPLE (Gavignaud, Bongiorno, Paltani et al, 2006)

3 23% I < 22.5 extended 35% I < 22.5 z<2.3 would be missed by standard pre-selection criteria Applying a morphological and colour analysis to our AGN sample: Morphological and color analysis 16/19 are at low redshift The VVDS type-1 AGN SAMPLE (Gavignaud, Bongiorno, Paltani et al, 2006)

4 Surface density: 32710823 47213024 1967622 712921 22920 10319 N(<I AB ) / deg 2 N I AB I AB < 24.0 N ~ 470  65 deg -2 Significantly higher than any other optically selected sample of BLAGN with spectroscopic confirmation z > 1.2 VVDS : N(R  24) = 340  47 COMBO-17: N(R  24) = 337 (Gavignaud, Bongiorno, Paltani et al, 2006) Number counts

5 Type-1 AGN Luminosity function: Model Fitting Luminosity-dependent density evolution (LDDE) PLE  variable:  2 = 130.4 =69 PLE+PDE:  2 = 91.4 =68 LDDE:  2 = 64.6 =67 Evolution of type-1 AGN (Bongiorno, Zamorani, Gavignaud et al., 2007) Double Power-law LF + evolution  (M B,z) =  (M B,0) * e(z(M B ) Good determination of the faint end of the LF Tests on various evolutionary laws

6 X-ray results on AGN evolution: The redshift at which the AGN density peaks, appears to be a function of luminosity NO Pure Luminosity or Density evolution but DIFFERENTIAL EVOLUTION Optical surveys: Evolution of type-1 AGN (Hasinger et al., 2005)(Wolf et al., 2003) M<-24 M<-25 M<-26 M<-27

7 From VVDS: The AGN activity as a function of redshift z peak ~ 2 @ M B < - 26 z peak ~ 0.65 @ -22 < M B < -20 Derived from our LDDE model fit Interpreted as evidence of AGN (i.e. black hole) “cosmic downsizing” The peak of the AGN comoving density shifts significantly towards lower redshift going to lower luminosity. Evolution of type-1 AGN (Bongiorno, Zamorani, Gavignaud et al., 2007)

8 From VVDS: AGN accretion as function of luminosity At z~1.5 the VVDS is sampling the faint end of the AGN LF. SMBH growth (Gavignaud, Wisotzki, Bongiorno et al., 2008) Epoch 2 sample: 298 BLAGN (222 wide +76 deep) Speculate that these AGN with low Eddington ratio correspond to a population of AGN which has exhausted most of its fuelling gas and is on its way to quiescence. Evidence for an evolution of accretion rate with luminosity: L ↓→ scatter in ε ↑ → ↓

9 IN PROGRESS… HST/NICMOS follow-up of the VVDS faintest AGN Link between M BH & Host properties Selection criteria: - Mg II virial mass (or ~ 1.1 < z < 1.8) - L bol < 10 45.5 erg/s → 14 targets Observation in H-band with NIC2 (Rest frame ~R; FOV 30”x30” ; 0.07” per pixel) All hosts are resolved with Host/Nucleus ranging from 0.4 to 20.0

10 Background… Link between M BH & Host properties bulge Locally we observe a tight correlation between BH mass and the bulge properties. The 3 main “flavours” of these relation are: M BH /σ * M BH /M dyn, bulge M BH /L bulge Haering & Rix 2004 Ferrarese & Meritt 2000 Marconi & Hunt 2003

11 Background… Link between M BH & Host properties Observing how these relations evolve with redshift constrains models of BH-Galaxy (co?-)evolution. (e.g. Granato 2004, Robertson 2006, Croton 2006,Hopkins 2009...) Currently for z>1, BH masses can be estimated only for broad line AGN MAIN PROBLEM: to estimate the properties of the host galaxies. This has been done with 3 main methods: Using gas emission lines (σ [OIII] and σ CO ) as surrogate for σ * Measuring the total luminosity of the host galaxy (best done with a B- V colour to constrain M/L ratio) SED fitting AGN+GALAXY decomposition --> K-band luminosity and host galaxy mass constrained (COSMOS; Merloni et al. - accepted) It seems that black holes have been growing faster at earlier epochs than their host galaxy (i.e. at high redshift SMBH are in “undersized” galaxies).

12 IN PROGRESS… HST/NICMOS follow-up of the VVDS faintest AGN Link between M BH & Host properties At z~1.4 AGN follow the local M BH /M* relation if we consider the total galaxy luminosity (i.e. no evolution) However, many hosts have a low Sersic index (n~1), indicating a significant disk component → transfer of mass from the disk to the bulges between z~1.5 and now? (A similar work with similar results (i.e. no evolution) has been done on COSMOS data (10 type 1 AGN with ACS and Nicmos observations) by Jahnke et al., 2009, submitted)

13 STILL to be Done (with the data at hands) A)Using this sample of type-1 AGN with Nicmos data Bulge/disk decomposition for the objects with the largest S/N ratio (IG). SED fitting AGN+GALAXY to derive the host galaxy mass and K-band luminosity (AB). Comparison with M* based on an assumed B-V color. To do B) Obscured/type-2 AGN Selection and properties of the obscured AGN population  Using spectral lines (AB+IG) (Based on work of the spectrophometric WG  do we have a problem here? )  Using SED (SP+MP) Evolution of type-2 AGN (VVDS+zCOSMOS+SDSS) and comparison with the evolution of the star forming galaxies … in progress (AB) …

14 PERSPECTIVES (on-going/future proposals...) Link M BH / Host: Get dynamical masses from the Ha emission of the disk (Submitted proposal: SINFONI) Reduce the uncertainties/systematic effects in BH virial masses: Get a direct calibration of the MgII and CIV line luminosity-size relations (Submitted proposal: VIMOS) Perspectives


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