1. 2006 December 6thMAGPOP La Palma Workshop Red Sequence formation ages Marc Balcells Collaborators GOYA Team: Carmen Eliche-Moral, David Cristóbal, Lilian Domínguez, Mercedes Prieto, Marc Vallbé, Carlos López Tenerife Nbody Team: Carmen Eliche-Moral, César González-García, Alfonso L. Aguerri Instituto de Astrofísica de Canarias

2. 2006 December 6thMAGPOP La Palma Workshop Summary Major epoch of E galaxy formation: 1 < z < 2 –Ancestors of L* ellipticals stopped making stars at z~1.5 (9 Gyr ago) Galaxies with centrally-peaked profiles (“with bulges”), 0.3 < z < 1.0: –Define a Red Sequence, of Bulge Colors –Galaxies without ~exponential profiles: color distribution does not show a Red Sequence –Galaxies with bulges: Integrated colors define a Red Sequence as well Redder bulges live in redder galaxies, with redder disks We don’t find red-old bulges surrounded by forming, blue disk Minor mergers make bulge grow from disk material

3. 2006 December 6thMAGPOP La Palma Workshop Work in preparation for GOYA survey Major study of high-z galaxy populations Using upcoming EMIR NIR multi-object spectrograph on 10.2 m GTC UFL, UCM, Toulouse, IAC –Guzmán, Gallego, Pelló, Balcells

4. 2006 December 6thMAGPOP La Palma Workshop Upcoming GTC Science funds “GTC Science ‘CONSOLIDER’ program –Spanish ministry of Science 5 yr, 5 Meuro Postdoc opportunities to be advertised ~2007 January Covering most science large programs with GTC –GOYA high-z NIR spectroscopy, EMIR –OTELO narrow-band tunable filter deep survey, OSIRIS –Massive stars in MW, OSIRIS, EMIR –Brown dwarfs, EMIR

5. 2006 December 6thMAGPOP La Palma Workshop GOYA Photometric Survey 0.5 square degree K=J=22 AB mag UBVRI=26 AB mag Fields: –Groth –GOODSN –V0226 –(COSMOS-10h) –Other, smaller fields (excluded from spectroscopic survey?) SA68 SIRTF-FLS Coppi

6. 2006 December 6thMAGPOP La Palma Workshop Galaxy number counts - Groth strip Blue band: power-law, up to B~25NIR band: break at K~17.5 Eliche-Moral et al (2006a) Cristóbal-Hornillos et al (2003)

7. 2006 December 6thMAGPOP La Palma Workshop Features in counts = features in LF Goal is to reproduce entire distribution of counts U,B,K 1.K counts change slope 2.U,B counts featureless power law Features in number counts = feature in LF Euclidean:

8. 2006 December 6thMAGPOP La Palma Workshop Modeling Evolution of local LF back in time –SDSS LFs, morphologically dependent Nakamura et al. 2003 –Ellipticals, early spirals, late spirals, Irregulars –No disappearing dwarf populations Observationally-motivated model ingredients –Number evolution ~(1+z) 2.0 –Extinction A B =0.6 (face-on), all galaxy classes –Salpeter IMF –Metallicities: Solar(E,Sa-b), 0.2solar(Sd), 0.1solar(Ir) Standard star formation histories –Instantaneous for ellipticals –Exponentially decaying for Spirals, Irregulars Only ‘free’ parameters: formation epoch for each galaxy class

9. 2006 December 6thMAGPOP La Palma Workshop Reproduce B,K counts Simultaneously reproduce number counts in Groth, U, B, Ks Eliche-Moral et al (2006a) Wide ranges - 18 mag in B, 10 mag in Ks Late z f =1.5 for ellipticals gives knee in Ks counts Ks~17.5 Extinction prevents bump from appearing in B Number evolution gives right overall slope

10. 2006 December 6thMAGPOP La Palma Workshop Limits on model parameters z f constrained for E. z f >2.5 does not work. For S0a-Sb, z f =1.5 to z f =4 good fit Extinction essential –A B =0.2 does not work Mergers essential –Otherwise, need to introduce a disappearing population –Moderate variations of rate are OK IMF, metallicities: little effect Instantaneous, SSP for ellipticals necessary

11. 2006 December 6thMAGPOP La Palma Workshop 9 Gyr broad agreement with other age determinations z=1.5: lookback-time 9 Gyr No major conflict with Population diagnostics –stellar populations of cluster ellipticals: age~12 Gyr Vazdekis –Field ellipticals, populations younger than 8 Gr Heavens et al 2005 Schiavon et al 2006 Distant Cluster Survey, CMD scatter: z form = 2.2 - 2.6 Taking ‘progenitor bias’ into account, ellipticals z form =2 Franx & Van Dokkum 1996 DEEP2 “picture”: RS starts at z=1.5 Michael Cooper, today GOODS-K20 morphology: E’s disappear by z=2 Cassata et al. (2004) –But is there a selection effect? –M K * =-23.6 has K S =20.6 at z=2

12. 2006 December 6thMAGPOP La Palma Workshop Duration of the elliptical formation epoch Model captures major growth phase of red sequence, 1<z<2 DRGs (Distant Red Gals) - evolved-SED galaxies 2<z<4 Franx et al 2003; Daddi et al. 2004; de Mello et al. 2004 –Model can accommodate a fraction of evolved galaxies at z>2 –Cluster ellipticals?; ours are field population. Many have star formation How much z<1 migration to red clump can be expected from data? 30% OK 50% (Bell et al. 2004; Faber et al 2005) probably OK, pushing it.

13. 2006 December 6thMAGPOP La Palma Workshop Physical processes? NCMOD did its best to reproduce the appearance of a red population at z~1.5 ?Seeing the formation of red, early types by mergers of Spirals? –Stars formed before –Merger-driven quenching of star formation ?Seeing the epoch when most halos reached M vir =6e11 M sun ? Birmboim & Dekel 03, Dekel & Birnboim 06 Cattaneo et al 2006 ?Mergers @ z<~1.5 involve more massive halos that shock the gas and inhibbit subsequent star formation? –Merger models not scale-free once gas cooling, heating is included ?Process probably related to morphological transition at z=1.5 Conselice 04

14. 2006 December 6thMAGPOP La Palma Workshop Inner structure of Red-Sequence galaxies Field galaxies, z=0.2 - 1.0 (Groth strip) Diameter-limited. Separate in two classes –With ~exponential surface brightness profile –With central surface brightness excess (“bulge galaxies”)

15. 2006 December 6thMAGPOP La Palma Workshop Colors of bulges and disks “Bulge” colors: on minor axis of inclined galaxy, choose bluest Disk colors: on face-on galaxies K-corrections (UBVIJK) –COSMOPACK tool Balcells & Cristóbal 2002 Completeness analysis –R>1.4” at z=0.8 matches large NGC spirals

16. 2006 December 6thMAGPOP La Palma Workshop Inner structure of Red-Sequence galaxies Find: –“Bulge galaxies” have a Red Sequence in bulge colors (R=0.2” ~ 1.5 kpc) –“Bulge galaxies” have Red Global colors U-B rest-frame BULGE colors, bulges vs no-bulges U-B rest-frame TOTAL colors, bulges vs no-bulges

17. 2006 December 6thMAGPOP La Palma Workshop Inner structure of Red-Sequence galaxies This means: –Disk galaxies in Red Sequence need to have a photometric bulge –Galaxies with Red bulges at z=0.8 had red disks at z=0.8 –Red bulges surrounded by a blue disk of active star formation are not seen in Groth up to z~0.8 B-R rest-frame nuclear colors strongly correlate with integrated galaxy colors Same as z=0 disk galaxies Peletier & Balcells 1996 For galaxies with and without bulges Domínguez & Balcells 2007

18. 2006 December 6thMAGPOP La Palma Workshop Cosmic Variance - GOODSN Mimicing analysis in GOODS-N Same red sequence in GOODSN ! –Previous claim for NO RED SEQ IN GOODS, due to an zeropoint error ….. (see our Abstract in Abstract book).

19. 2006 December 6thMAGPOP La Palma Workshop Minor mergers Accreting disk satellites onto disk galaxies –TF scaling primary-secondary Result: Little satellite mass deposition in bulge Inward transport of disk matter Bulge growth out of disk material triggered by accretion Eliche-Moral et al 2006b

20. 2006 December 6thMAGPOP La Palma Workshop Accretion-driven B/D growth B/D increases with each accretion, together with Sersic index of bulge. Even if no satellite matter reaches the center ! Eliche-Moral et al 2006b

21. 2006 December 6thMAGPOP La Palma Workshop Summary Major epoch of E galaxy formation: 1 < z < 2 –Ancestors of L* ellipticals stopped making stars at z~1.5 (9 Gyr ago) Galaxies with centrally-peaked profiles (“with bulges”), 0.3 < z < 1.0: –Define a Red Sequence, of Bulge Colors –Galaxies without ~exponential profiles: color distribution does not show a Red Sequence –Galaxies with bulges: Integrated colors define a Red Sequence as well Redder bulges live in redder galaxies, with redder disks We don’t find red-old bulges surrounded by forming, blue disk Minor mergers make bulge grow from disk material