ESO

Radio observations of the formation of the first galaxies and supermassive Black Holes

Chris Carilli (NRAO)LANL Cosmology School, July 2010

• Concepts and tools in radio astronomy: dust, cool gas, and star formation

• Quasar host galaxies at z=6: coeval formation of massive galaxies and SMBH within 1 Gyr of the Big Bang

• Quasar near-zones and reionization

•Bright future: pushing to normal galaxies with the Atacama Large Millimeter Array and Expanded Very Large Array – recent examples!

Collaborators: R.Wang, D. Riechers, Walter, Fan, Bertoldi, Menten, Cox, Strauss, Neri

Millimeter through centimeter astronomy: unveiling the cold, obscured universe

GN20 SMG z=4.0

Galactic

Submm = dustoptical CO

• optical studies provide a limited view of star and galaxy formation• cm/mm reveal the dust-obscured, earliest, most active phases of star and galaxy formation

HST/CO/SUBMM

mid-IR

Cosmic ‘Background’ Radiation

Franceschini 2000

Over half the light in the Universe is absorbed by dust and reemitted in the FIR

30 nW m-2 sr-1

17 nW m-2 sr-1

Radio – FIR: obscuration-free estimate of massive star formation

Radio: SFR = 1x10-21 L1.4 W/Hz

FIR: SFR = 3x10-10 LFIR (Lo)

Magic of (sub)mm: distance independent method of studying objects in universe from z=0.8 to 10

LFIR ~ 4e12 x S250(mJy) Lo SFR ~ 1e3 x S250 Mo/yr

FIR = 1.6e12 L_sun

obs = 250 GHz

1000 Mo/yr

7

Spectral lines

Molecular rotational lines

Atomic fine structure lines

z=0.2

z=4

cm submm

Molecular gas

CO = total gas masses = fuel for star formation

M(H2) = α L’(CO(1-0))

Velocities => dynamical masses

Gas excitation => ISM physics (densities, temperatures)

Dense gas tracers (eg. HCN) => gas directly associated with star formation

Astrochemistry/biology

Wilson et al.

CO image of ‘Antennae’ merging galaxies

Fine Structure lines

[CII] 158um (2P3/2 - 2P1/2)

Principal ISM gas coolant: efficiency of photo-electric heating by dust grains.

Traces star formation and the CNM

COBE: [CII] most luminous cm to FIR line in the Galaxy ~ 1% Lgal

Herschel: revolutionary look at FSL in nearby Universe – AGN/star formation diagnostics

[CII] CO [OI] 63um [CII]

[OIII] 88um [CII][OIII]/[CII]

Cormier et al.

Fixsen et al.

Plateau de Bure Interferometer

High res imaging at 90 to 230 GHz

rms < 0.1mJy, res < 0.5”

MAMBO at 30m

30’ field at 250 GHz rms < 0.3 mJy

Very Large Array

30’ field at 1.4 GHz

rms< 10uJy, 1” res

High res imaging at 20 to 50 GHz

rms < 0.1 mJy, res < 0.2”

Powerful suite of existing cm/mm facilites

First glimpses into early galaxy formation

Massive galaxy and SMBH formation at z~6: gas, dust, star formation in quasar hosts Why quasars?

Rapidly increasing samples:

z>4: > 1000 known

z>5: > 100

z>6: 20

Spectroscopic redshifts

Extreme (massive) systems

MB < -26 =>

Lbol > 1014 Lo

MBH > 109 Mo (Eddington / MgII)

1148+5251 z=6.42

SDSSApache Point NM

Gunn-Peterson Effect

Fan et al 2006

SDSS z~6 quasars => tail-end of reionization and first (new) light?

z=6.4

5.7

6.4

QSO host galaxies MBH – Mbulge relation

All low z spheroidal galaxies have SMBH: MBH=0.002 Mbulge

‘Causal connection between SMBH and spheroidal galaxy formation’

Luminous high z quasars have massive host galaxies (1012 Mo)

Haaring & Rix

Nearby galaxies

Cosmic Downsizing

Massive galaxies form most of their stars rapidly at high z

tH-1tH-1

Currently active star formation

Red and dead => Require active star formation at early times

Zheng+

~(e-folding time)-1

• Massive old galaxies at high z• Stellar population synthesis in nearby ellipticals

• 30% of z>2 quasars have S250 > 2mJy

• LFIR ~ 0.3 to 1.3 x1013 Lo (~ 1000xMilky Way)

• Mdust ~ 1.5 to 5.5 x108 Mo

HyLIRG

Dust in high z quasar host galaxies: 250 GHz surveys

Wang sample 33 z>5.7 quasars

Dust formation at tuniv<1Gyr?

• AGB Winds ≥ 1.4e9yr

High mass star formation? (Dwek, Anderson, Cherchneff, Shull, Nozawa)

‘Smoking quasars’: dust formed

in BLR winds (Elvis)

ISM dust formation (Draine)

• Extinction toward z=6.2 QSO and z~6 GRBs => different mean grain properties at z>4 (Perley, Stratta)

Larger, silicate + amorphous carbon dust grains formed in core collapse SNe vs. eg. graphite

Stratta et al.

z~6 quasar, GRBs

Galactic

SMC, z<4 quasars

Dust heating? Radio to near-IR SED

TD = 47 K FIR excess = 47K dust

SED consistent with star forming galaxy:

SFR ~ 400 to 2000 Mo yr-1 Radio-FIR correlation

low z SED

TD ~ 1000K

Star formation?

AGN

Fuel for star formation? Molecular gas: 8 CO detections at z ~ 6 with PdBI, VLA

• M(H2) ~ 0.7 to 3 x1010 (α/0.8) Mo • Δv = 200 to 800 km/s1mJy

CO excitation: Dense, warm gas, thermally excited to 6-5

• LVG model => Tk > 50K, nH2 = 2x104 cm-3

• Galactic Molecular Clouds (50pc): nH2~ 102 to 103 cm-3

• GMC star forming cores (≤1pc): nH2~ 104 cm-3

Milky Way

starburst nucleus

230GHz 691GHz

LFIR vs L’(CO): ‘integrated Kennicutt-Schmidt star formation law’

Index=1.5

1e11 Mo

1e3 Mo/yr

• Further circumstantial evidence for star formation

• Gas consumption time (Mgas/SFR) decreases with SFRFIR ~ 1010 Lo/yr => tc~108yrFIR ~ 1013 Lo/yr => tc~107yr

=> Need gas re-supply to build giant elliptical

SFR

Mgas

MW

1148+52 z=6.42: VLA imaging at 0.15” resolution

IRAM

1” ~ 6kpc

CO3-2 VLA

‘molecular galaxy’ size ~ 6 kpc – only direct observations of host galaxy of z~6 quasar!

Double peaked ~ 2kpc separation, each ~ 1kpc

TB ~ 35 K ~ starburst nuclei

+0.3”

CO only method for deriving dynamical masses at these distances

Dynamical mass (r < 3kpc) ~ 6 x1010 Mo

M(H2)/Mdyn ~ 0.3

Gas dynamics => ‘weighing’ the first galaxies

z=6.42

-150 km/s

+150 km/s

7kpc

Dynamical masses ~ 0.4 to 2 x1011 Mo

M(H2)/Mdyn ≥ 0.5 => gas/baryons dominate inner few kpc

Gas dynamics: CO velocities

z=4.19z=4.4-150 km/s

+150 km/s

Break-down of MBH – Mbulge relation at very high z

z>4 QSO CO

z<0.2 QSO CO

Low z galaxies

Riechers +

<MBH/Mbulge> ~ 15 higher at z>4 => Black holes form first?

Wang z=6 sample: galaxy mass vs. inclination, assuming all have CO radii ~ J1148+5251

• Departure from MBH – Mbulge at highest z, or

•All face-on: i < 20o

Wang +

Low z MBH/Mbulge

For z>6 => redshifts to 250GHz => Bure!

1”

[CII]

[NII]

[CII] 158um search in z > 6.2 quasars

•L[CII] = 4x109 Lo (L[NII] < 0.1L[CII] )

•S250GHz = 5.5mJy

•S[CII] = 12mJy

• S[CII] = 3mJy

• S250GHz < 1mJy=> don’t pre-select on dust

1148+5251 z=6.42:‘Maximal star forming disk’

• [CII] size ~ 1.5 kpc => SFR/area ~ 1000 Mo yr-1 kpc-2

• Maximal starburst (Thompson, Quataert, Murray 2005)

Self-gravitating gas and dust disk

Vertical disk support by radiation pressure on dust grains

‘Eddington limited’ SFR/area ~ 1000 Mo yr-1 kpc-2

eg. Arp 220 on 100pc scale, Orion SF cloud cores < 1pc

PdBI 250GHz 0.25”res

[CII]

• [CII]/FIR decreases with LFIR = lower gas heating efficiency due to charged dust grains in high radiation environments

• Opacity in FIR may also play role (Papadopoulos)

Malhotra

[CII]

• HyLIRG at z> 4: large scatter, but no worse than low z ULIRG

• Normal star forming galaxies are not much harder to detect in [CII] (eg. LBG, LAE)

Maiolino, Bertoldi, Knudsen, Iono, Wagg

z >4

A starburst to quasar sequence at the highest z?Anticorrelation of EW(Lya) with submm detections

• Strong FIR => starburst• Weak Lya => young quasar, prior to build-up of BLR (?)• Consistent with ‘Sanders sequence’: starburst to composite to quasar

Submm dust

No Dust

Submm dust

No Dust

11 in mm continuum => Mdust ~ 108 Mo: Dust formation in SNe?

10 at 1.4 GHz continuum: Radio to FIR SED => SFR ~ 1000 Mo/yr

8 in CO => Mgas ~ 1010 Mo = Fuel for star formation in galaxies

High excitation ~ starburst nuclei, but on kpc-scales

Follow star formation law (LFIR vs L’CO): tc ~ 107 yr

3 in [CII] => maximal star forming disk: 1000 Mo yr-1 kpc-2

Departure from MBH – Mbulge at z~6: BH form first?

Anticorrel. EW(Lya) with submm detections => SB to Q sequence

J1425+3254 CO at z = 5.9

Summary cm/mm observations of 33 quasars at z~6: only direct probe of the host galaxies

EVLA160uJy

Extreme Downsizing: Building a giant elliptical galaxy + SMBH at tuniv< 1Gyr

Plausible? Multi-scale simulation

isolating most massive halo in 3 Gpc3

Stellar mass ~ 1e12 Mo forms in series (7) of major, gas rich mergers from

z~14, with SFR 1e3 Mo/yr

SMBH of ~ 2e9 Mo forms via Eddington-limited accretion + mergers

Evolves into giant elliptical galaxy in massive cluster (3e15 Mo) by z=0

6.5

10

• Rapid enrichment of metals, dust in ISM

• Rare, extreme mass objects: ~ 100 SDSS z~6 QSOs on entire sky

• Goal: push to normal galaxies at z > 6

Li, Hernquist et al. Li, Hernquist+

ESO

BREAKDiscussion points: 1.Dust formation within 1Gyr of Big Bang?2.Evolution of MBH – Mbulge relation?3.Starburst to quasar sequence: duty cycles and timescales?4.Gas resupply (CMA, mergers)?5.FIR – EW(Lya) anti-correlation?

Quasar Near Zones: J1148+5251

• Accurate host galaxy redshift from CO: z=6.419• Quasar spectrum => photons leaking down to z=6.32

White et al. 2003

• ‘time bounded’ Stromgren sphere ionized by quasar

• Difference in zhost and zGP =>

RNZ = 4.7Mpc [fHI Nγ tQ]1/3 (1+z)-1

HI

Loeb & Barkana

HII

Quasar Near-Zones: sample of 25 quasars at z=5.7 to 6.5 (Carilli et al. 2010)

I.Host galaxy redshifts: CO (6), MgII (11), UV (8)

I.GP on-set redshift:•Adopt fixed resolution of 20A•Find 1st point when transmission drops below 10% (of extrapolated) = well

above typical GP level.

Wyithe et al. 2010

z = 6.1

Quasar Near-Zones: Correlation of RNZ with UV luminosity

Nγ1/3

LUV

•<RNZ> decreases by factor 2.3 from z=5.7 to 6.5 => fHI increases by factor 9• Pushing into tail-end of reionization?

RNZ = 7.3 – 6.5(z-6)

Quasar Near-Zones: RNZ vs redshift

z>6.15

Alternative hypothesis to Stromgren sphere: Quasar Proximity Zones (Bolton & Wyithe)

• RNZ measures where density of ionizing photon from quasar > background photons (IGRF) =>

RNZ [Nγ]1/2 (1+z)-9/4

• Increase in RNZ from z=6.5 to 5.7 is then due to rapid increase in mfp and density of ionizing background during overlap or ‘percolation’ stage of reionization

• Either case (CSS or PZ) => rapid evolution of IGM from z ~ 6 to 6.5

What is Atacama Large Milllimeter Array?North American, European, Japanese, and Chilean collaboration to build & operate a large millimeter/submm array at high altitude site (5000m) in northern Chile => order of magnitude, or more, improvement in all areas of (sub)mm astronomy, including resolution, sensitivity, and frequency coverage.

ALMA Specs

• High sensitivity array = 54x12m

• Wide field imaging array = 12x7m antennas

• Frequencies = 80 GHz to 720 GHz

• Resolution = 20mas res at 700 GHz

• Sensitivity = 13uJy in 1hr at 230GHz

What is EVLA? First steps to the SKA-high

By building on the existing infrastructure, multiply ten-fold the VLA’s observational capabilities, including:

10x continuum sensitivity (1uJy)

Full frequency coverage (1 to 50 GHz)

80x Bandwidth (8GHz) + 104 channels

40mas resolution at 40GHz

Overall: ALMA+EVLA provide > order magnitude improvement from 1GHz to 1 THz!

(sub)mm: dust, high order molecular lines, fine structure lines -- ISM physics, dynamics

cm telescopes: star formation, low order molecular transitions -- total gas mass, dense gas tracers

Pushing to normal galaxies: spectral lines

100 Mo yr-1 at z=5

ALMA and first galaxies: [CII] and Dust

100Mo/yr

10Mo/yr

Wide bandwidth spectroscopy

• ALMA: Detect multiple lines, molecules per 8GHz band

• EVLA 30 to 38 GHz = CO2-1 at z=5.0 to 6.7 => large cosmic volume searches for molecular gas (1 beam = 104 cMpc3) w/o need for optical redshifts

J1148+52 at z=6.4 in 24hrs with ALMA

ALMA Status•Antennas, receivers, correlator in production: best submm receivers and antennas ever!•Site construction well under way: Observation Support Facility, Array Operations Site, 5 Antenna interferometry at high site!• Early science call Q1 2011

embargoed

first light image

EVLA Status

• Antenna retrofits 70% complete (100% at ν ≥ 18GHz).

• Full receiver complement completed 2012 with 8GHz bandwidth

• Early science started March 2010 using new correlator (up to 2GHz bandwidth) – already revolutionizing our view of galaxy formation!

GN20 molecule-rich proto-cluster at z=4CO 2-1 in 3 submm galaxies, all in 256 MHz band

4.051

z=4.055

4.056

0.7mJyCO2-1 46GHz

0.4mJy

1000 km/s

0.3mJy

• SFR ~ 103 Mo/year

• Mgas > 1010 Mo

• Early, clustered massive galaxy formation

GN20 z=4.0

VLA: ‘pseudo-continuum’ 2x50MHz channels

EVLA: well sampled velocity field

GN20 moment images

+250 km/s

-250 km/s

• Low order CO emitting regions are large (10 to 20 kpc)

• Gas mass = 1.3e11 Mo

• Stellar mass = 2.3e11 Mo

• Dynamical mass (R < 4kpc) = 3e11 Mo

=> Baryon dominated within 4kpc

CO excitation => ISM conditions • nH2 ~ 104.3 cm-3

• TK ~ 45 K

Most distant SMG: z=5.3 (Riechers et al)

EVLA

Bure

CO 1-0 in normal galaxies at z=1.5 (‘sBzK’ galaxies)

4”

• SFR ~ 10 to 100 Mo/year

• Find: MH2 > 1010 Mo> Mstars => early stage of MW-type galaxy formation?

• Again: low order CO is big (28kpc)

• Milky Way-like CO excitation (low order key!)

•10x more numerous than SMGs

500 km/s

Bure 2-1 HST

EVLA 1-0

0.3mJy

Dense gas history of the Universe: the ‘other half’ of galaxy formation Tracing the fuel for galaxy formation over cosmic time

SF law

Millennium Simulations Obreschkow & Rawlingn

Major observational goal for next decade

EVLA/ALMA Deep fields: 1000hr, 50 arcmin2

• Volume (EVLA, z=2 to 2.8) = 1.4e5 cMpc3

• 1000 galaxies z=0.2 to 6.7 in CO with M(H2) > 1010 Mo

• 100 in [CII] z ~ 6.5

• 5000 in dust continuum

ENDDiscussion points1.Stromgren spheres vs. Proximity zones?2.DGHU, star formation laws, and CO to H2 conversion factors?3.Role of EVLA/ALMA in first galaxy studies?

cm: Star formation, AGN

(sub)mm Dust, FSL, mol. gas

Near-IR: Stars, ionized gas, AGN

Pushing to normal galaxies: continuum

A Panchromatic view of 1st galaxy formation

100 Mo yr-1 at z=5

Comparison to low z quasar hosts

IRAS selected

PG quasars

z=6 quasars

Stacked mm non-detections

Hao et al. 2005

Molecular gas mass: X factor

M(H2) = X L’(CO(1-0))

Milky way: X = 4.6 MO/(K km/s pc^2) (virialized GMCs)

ULIRGs: X = 0.8 MO/(K km/s pc^2) (CO rotation curves)

Optically thin limit: X ~ 0.2

Downes + Solomon

CO excitation = Milky Way (but mass > 10xMW)

FIR/L’CO Milky Way

Gas depletion timescales > few x108 yrs

HyLIRG

Dannerbauer + Daddi +

Milky Way-type gas conditions

1

1.5

Mgas

SFR

Building a giant elliptical galaxy + SMBH at tuniv< 1Gyr

6.5

10

• Rapid enrichment of metals, dust in ISM

• Rare, extreme mass objects: ~ 100 SDSS z~6 QSOs on entire sky

Issues and questions:

• Duty cycle for star formation and SMBH accretion very high?

• Gas resupply: not enough to build GE

• Goal: push to normal galaxies at z > 6 IssuesLi, Hernquist et al.

Quasar Near-Zones

Nγ1/3

• Correlation of RNZ with UV luminosity• No correlation of UV luminosity with redshift

LUV