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Cracking the mystery of galaxy and black hole formation:
rachel somervilleMPIA/STScI
a Theorists’ Wish List for the next generation of Space Telescopes
Progress in the last 10-15 years
CDM paradigm shown to be consistent with broad range of observations (CMB, Ly- forest, weak lensing, galaxy clustering, galaxy clusters)galaxy surveys:
large homogeneous samples at low z huge progress in discovering & cataloging high-z
galaxies build-up of panchromatic view of the Universe
development of detailed simulations of dark matter and (to some extent) gas processes developments of (not totally im-)plausible picture for galaxy formation within this framework -- but...
Moster, rss et al. in prep; Benson et al. 2003; Somerville & Primack 1999
‘special’ scale Mh~1012 Msun
we still have to invoke several “tooth fairies” in order to reconcileCDM with fundamental observations:
stellar mass function andDM halo mass function
fract
ion o
f b
ary
on
s in
sta
rs
Moster, rss et al. in prep; Benson et al. 2003; Somerville & Primack 1999
we still have to invoke several “tooth fairies” in order to reconcileCDM with fundamental observations:
“Supernova feedback”
“AGN feedback”
The Biggest Outstanding Problems in Galaxy Formation
physics of star formation & stellar feedback from Giant Molecular Cloud (core) to galactic scalesinterconnection of galaxies and their (growing) black holes
The mysteries of cooling flows, overcooling, and quenched galaxies
z=1
Bell et al. 2005
Peterson & Fabian 2006
• why isn’t gas cooling (below 1/3 Tvir) in the centers of clusters?• what sets the maximum mass scale for galaxies (M* ~ 1012 Msun)?
• why is star formation“quenched” in massive, spheroidal galaxies?• why are galaxy propertiesstrongly bimodal?
gastrophysics or particle physics?
many dwarf & LSB galaxies have lower central densities and less “cuspy” density profiles than predicted by standard LCDM:
nature of dark matter or primordial power spectrum (e.g. Zentner & Bullock 2002; Strigari et al. 2007)
or stellar feedback (e.g. Mashchenko et al. 2007)?
rota
tion
velo
city
Simon et al. 2005(see also de Blok 2005)
Star formation and stellar/supernova feedback
what determines the efficiency of star formation on galactic scales? what drives the dependence on galaxy mass, redshift, or other properties?how effective are supernova-driven winds at heating and expelling gas from galaxies?
Kennicutt et al. 2007
Kennicutt et al. 1989
starbursts
galacticnuclei
normalgalaxies
requirements for sub-galactic resolution studies at high redshift
SDSS
HST z~1.2
the co-evolution of galaxies, AGN and SMBH
how did the first (seed) BH form and what were their masses?how was their growth triggered and regulated (mergers/bars, ADAFs, super-Eddington accretion)?How did BH spins evolve over time (related to efficiency of converting matter into energy)How does the energy from growing BH impact the host galaxy and its surroundings (winds, heating)?
understanding galaxy & BH formation: challenges
dynamic range: Gpc (luminous QSO) few 100 Mpc (LSS) 10’s of kpc - Mpc (ICM, jets) sub-kpc to kpc (star formation,
stellar FB) few 100 pc (nuclear gas inflows,
starbursts, AGN feeding, winds) pc & sub-pc (accretion disk, BH
mergers, etc)poorly understood physics (B-fields, conduction, cosmic ray pressure, turbulence, feeding problem, BH mergers...)
AGN feedback 1: bright mode
optical/X-ray luminous AGN/QSO, produced during periods of efficient feeding (mergers?)high accretion rates (0.1-1 LEdd), fueled by cold gas via thin accretion disk --> BH grows rapidlyrare-->duty cycle short radiation pressure can drive winds and perhaps galactic-scale outflows
Di Matteo, Springel & Hernquist 2005
lots of circumstantial evidence that (optical/X-ray bright) AGN are associated with quenching of SF...
weak AGN at z=0 live in massive, spheroids with young stellar pops; many are post-starburst (Kauffmann et al. 2003)strong correlation of with color; almost all ‘green valley’ galaxies host weak AGN (Kaviraj et al. 2006; Kauffmann et al. 2006; Salim et al. 2007)similar results seen for AGN to z~1 (GEMS: Sanchez et al. 2004; AEGIS: Pierce et al. 2006; Nandra et al. 2007)
Kauffmann et al. 2006
AGN
AGN-driven Winds
even more suspiciously, (a few of) these same post-starburst (green valley) galaxies show signatures of high velocity windssuch winds known to be fairly common in Seyferts and QSOs (e.g. Kriss 2002; Ganguly et al. 2001, 2007)but, typically covering fraction, column density & ionization state unknown -- hence mass outflow rates uncertain Tremonti, Moustakas, &
Diamond-Stanic 2007
AGN feedback 2: Radio ModeAGN feedback 2: Radio Mode
RadioRadio X-rayX-ray
3C843C84
many massive galaxies are ‘radio loud’radio activity believed to be associated with BH’s in ‘low accretion state’ (low Eddington ratio, <10-3) --(spherical, Bondi accretion or ADAF?)radio jets often associated with cavities visible in X-ray images; apparently they can very efficiently heat the surrounding hot gas and perhaps balance cooling...
FR IFR II
X-ray bubbles as ‘calorimeters’
Allen et al. 2006
the jet power (determined from energetics of X-ray bubbles) is proportional to the Bondi accretion rate.
Obtain X-ray maps &ancillary multi- datafor large sample of groups & clusters (tohigh redshift)
The BH Fundamental Planeblack hole masses in nearby galaxies are strongly correlated with many galaxy properties: L, Msph, , ns, re recently suggested that MBH possesses a “fundamental plane”, similar to that for galaxies (Hopkins et al. 2007)
Ferrarese & Merritt 2000Gebhardt et al. 2000
a similar “fundamental plane” is seen in the remnants of hydrodynamic simulations of galaxy mergers including BH growth and feedbackgas-rich mergers suffer dissipation and form a deeper potential well than gas-poor mergersrequires more energy, hence a larger BH to halt accretion in remnants of gas-rich mergers
Hopkins et al. 2007, astro-ph/0701351
gas fraction
BH/bulge mass
Physical origin of the BH FP?
strong prediction: evolution of mBH/msph with z; relationship with fgas and galaxy structural properties
Hopkins et al. 2007, astro-ph/0701351
measure BH masses and galaxy spheroid masses, sizes, and velocity dispersions over the broadest possible redshift range
Mission baseline: • 1.2m telescope• Visible: 0.5 deg2, pixels 0.10’’, broad R+I+Z, e2v CCDs• NIR: 0.5 deg2, pixels 0.15’’, Y,J,H, Teledyne HgCdTe• Dichroic Mirror• PSF FWHM 0.23’’, 2.2 pix/FWHM (vis)• GEO (or HEO) orbit with Soyuz Launch• 4-year mission
“All-sky” (20,000 sq.deg.)optical & NIR surveys
Imaging Survey Discovery Space:
Niche for wide field NIR imaging surveys -- HUGE advantages to going to space
High redshift (proto-) clusters from wide-field NIR imaging
use J-H to identify “red sequence” clusters to z=2-3 expect several 100 Virgo-mass
clusters & several 1000 M>1013 Msun “proto-clusters” at z>2
targets for study with ground-based radio facilities &next generation X-ray telescopes -- these should be theenvironments & redshifts of maximal AGN feedback!
Extreme Black Holesthe existence of luminous QSO’s at z>6 are already on the edge for the most “vanilla” picture of BH formation
super-Eddington accretion?
seed BH masses? spin up of BH? BH loss mechanisms
(recoil, rocket, slingshot)?
Jiang et al. 2007
Li et al. 2007; Volonteri & Rees 2006; Yoo & Miralda-Escude 2004; Haiman 2004; Bromley, rss & Fabian 2004
Searching for z>6.5 QSO’s“cloned” 215-some QSO spectra from SDSS (2.2<z<2.25) at higher redshift (including IGM absorption) to compute observed-frame colors in DUNE-like photometric system (ZYJH)
Fontanot, rss, Jester (astro-ph/0711.1440)
Color Selection of high-z QSO’s
can disentangleQSO’s from brown dwarfs
FSJ08
Luminosity Function Evolution
use observed QSO luminosity function at z=3.5-5.2, (SDSS+GOODS) plus simple model(s) for its evolution
Predicted high-z QSO counts
blue hatched: non-evolving F07 LF
yellow shaded: evolving F07 LF
red lines: steepestallowed LF at z~6,from Shankar &Mathur (2007) (evolving/non-evolving)
Fontanot, rss & Jester (2008)
DUNE
JWST
VISTA
Expected “backwards” evolution of most luminous z~6 QSO’s
r = 0.1
DUNE
JWST
Lyman break galaxies at z>7
Courtesy of C. Lacey
a DUNE Medium-deeplike survey would becomplementary to JWST for identifyinghigh redshift galaxies
JWST
DUNE
Wish List:
constrain relationship between DM and galaxies: mass maps from weak lensing, galaxy properties such as stellar mass, SFR, morphology, AGN activityconstrain mass outflow rates of stellar & AGN-driven winds (and dependence on luminosity, redshift, environment, etc) measure efficiency of “radio mode” heating via high spatial resolution X-ray imaging & radio observations of groups and clusters to z=2-3measure BH masses and galaxy masses, sizes, and kinematics to highest possible redshiftsfind the most luminous z>6 galaxies and QSOs
how wide do we need to go to overcome cosmic variance?
assuming redshiftshells z=0.1
how wide do we need to go to overcome cosmic variance?
‘typical’(b=1) galaxies
strongly clustered galaxies(EROs, proto-ellipticals, SCUBA galaxies)
constant minimum mass
constant number density
cosmic variance cheat sheet: rss et al. 2004
HOD model details in Moustakas & rss 2002
fract
ional ro
ot
vari
an
ce
how wide do we need to go to overcome cosmic variance?
‘typical’
(b=1) galaxies
strongly clustered galaxies
how wide do we need to go to overcome cosmic variance?
strongly clustered galaxies
‘typical’
(b=1) galaxies
how wide do we need to go to overcome cosmic variance?
‘typical’
(b=1) galaxies
strongly clustered galaxies
• DUNE Extragalactic All-Sky Survey: 20,000 deg2, |b|>30o, R+I+Z=24.5 (10s ext.), Y,J,H=24 (5s, PS), 40 WL galaxies/arcmin2, zm~1, photo-z with ground-based complement, 3 years• Medium Deep Survey: 2x50 deg2, R+I+Z=26.5 (10s extended), Y,J,H=26 (5s, PS), 6 months• DUNE Galactic Plane Survey: 21,000 deg2, |b|>30o R+I+Z=23.8, Y,J,H=22 (5s, PS), complete 4 coverage, 3 months• Microlensing Survey (DUNE-ML): 4 deg2 in the bulge, visited every 20 minutes over 3 months (Y,J,H~22 per visit), 3 months
Proposed DUNE Surveys
Galactic Plane21,000 deg2
Medium-Deep2x50 deg2
Microlensing4 deg2
Wide Extragalactic20,000 deg2
Weak Gravitational Lensing
z>1
z<1
• central goal of DUNE• constrain dark energy• map dark matter
Weak Lensing tomography:
Jain et al. 1997
130kpc resolution at supercluster redshift z=0.16
STAGES survey Heymans et al. submitted
Total Mass to stellar
mass ratio
Log
(M/M
*)
Old Red
Galaxies
Dusty Red Galaxies
Blue Galaxies
Courtesy of C. Heymans