ESO

ALMA, EVLA, and the Origin of Galaxies(Dense Gas History of the Universe)

Chris Carilli (NRAO)Bonn, Germany, September 2010

• The power of radio astronomy: dust, cool gas, and star formation

• Current State-of-Art z ~ 6: Quasar host galaxies = early formation of massive galaxies and SMBH z ~ 1 to 3: Normal galaxy formation during the epoch of galaxy assembly = probing the ‘Gas Rich Universe’

• Bright (near!) future: The Atacama Large Millimeter Array (and CCAT!) and Expanded Very Large Array – recent example!

Thanks: Wang, Riechers, Walter, Fan, Bertoldi, Menten, Cox, Daddi, Schinnerer, Pannella, Aravena, Smolcic, Neri, Dannerbauer…

Star formation history of the Universe (mostly optical view)

‘epoch of galaxy assembly’

~50% of present day stellar mass produced between z~1 to 3

Bouwens +

First light + cosmic reionization

Star formation as function of stellar mass

tH-1tH-1

‘active star formation’

‘red and dead’

Zheng ea

‘Downsizing’: Massive galaxies form most of stars quickly, at high z

(see also: stellar pop. synthesis at low z; evolved galaxies at z ~1 to 2)

specific SFR = SFR/M* ~

e-folding time-1

Optical Limitation 1: Dust

Bouwens +

Optical Limitation 2: Cold gas = fuel for star formation (‘The missing half of galaxy formation’)

Low z spirals

Integrated Kennicutt-Schmidt star formation law: relate SFR and gas content of galaxies

Power-law index = 1.5‘SFR’

‘Mgas’

Millimeter through centimeter astronomy: unveiling the cold, obscured universe

• cm/mm reveal the dust-obscured, earliest, most active phases of star formation in galaxies• cm/mm reveal the cool gas that fuels star formation

HST/CO/SUBMM

CO

Wilson et al.

CO image of ‘Antennae’ merging galaxies

GN20 z=4 submm galaxy

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

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

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

Spectral lines

Molecular rotational lines

Atomic fine structure lines

z=0.2

z=4

cm submmMolecular gas

• CO = total gas mass tracer

M(H2) = α L’(CO(1-0))

• Velocities => dyn. mass

• Gas excitation => ISM physics (densities, temperatures)

• Astrochemistry/biology, eg. dense gas tracers (HCN) directly associated with star formation (Smail, van Dishoeck)

•Gas supply: smooth accretion or major gas rich mergers?

Fine Structure lines

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

Principal ISM gas coolant: photo-electric heating by dust

Traces star forming regions and the CNM

[CII] most luminous line from meter to FIR, up to 1% Lgal

Herschel: revolutionary look at FSL in nearby Universe – AGN/star formation diagnostics (Hailey-Dunsheath)

[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

(Cox)

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

Theme I: Massive galaxy and SMBH formation at z~6 – Quasar hosts at tuniv<1Gyr

Why quasars?

Rapidly increasing samples: z>4: > 1000 known

z>5: > 100

z>6: 20

Spectroscopic redshifts

Extreme (massive) systems: Lbol ~1014 Lo=> MBH~ 109 Mo => Mbulge ~ 1012 Mo

Downsizing: study of very early massive galaxy formation intrinsically interesting

1148+5251 z=6.42

SDSSApache Point NM

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

• Mdust ~ 1.5 to 5.5 x108 Mo

• Dust formation at tuniv<1Gyr? AGB Winds ≥ 1.4e9yr

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

HyLIRG

Dust in high z quasar host galaxies

30% of z>2 quasars have S250 > 2mJy

Wang sample 33 z>5.7 quasars

MAMBO 30m 250GHz surveys

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/s• Accurate host galaxy redshifts

1mJy

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 (Papadopoulos, Smail)

LFIR vs L’(CO): 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

SFR

Mgas

MW

Size ~ 6 kpc, with two peaks ~ 2kpc separation

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

M(H2)/Mdyn ~ 0.3

Imaging => dynamics => weighing the first galaxies

z=6.42

-150 km/s

+150 km/s

7kpc

1” ~ 5.5kpc

CO3-2 VLA

+

0.15” TB ~ 25K

PdBI

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

z>4 QSO CO

z<0.2 QSO CO

Low z galaxies

MBH ~ 0.002Mbulge

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

(Maiolino)

•‘Causal connection between galaxy and SMBH formation’

• At high z, CO only method to derive Mbulge

For z>6 => redshifts to 250GHz => Bure! (Knudsen)

1”

[CII]

[NII]

Fine Structure Lines: [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

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

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

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

J1425+3254 CO at z = 5.9

Theme I summary: cm/mm observations of 33 quasars at z~6 – only direct probe of the host galaxies

EVLA160uJy

Building a giant elliptical galaxy + SMBH at tuniv< 1Gyr (‘extreme downsizing’)

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 high redshift

Li, Hernquist et al. Li, Hernquist+

HST

Theme II: ‘Normal’ star forming galaxies during epoch of galaxy assembly (‘sBzK’ at z ~ 2)

color-color diagrams identify thousands of z~ 2 star forming galaxies

near-IR selected => ‘stellar mass limited sample’: M* ~ 1010 to 1011Mo

Common ~ few x10-4 Mpc-3 (5 arcmin-2)

• HST imaging => disk sizes ~ 1” ~ 8kpc, punctuated by massive star forming regions

<SFR> = 96 Mo yr-1 [FIR ~ 3e11 Lo]

VLA size ~ 1” ~ HST

Pannella +

<S1.4> = 8.8 +/- 0.1 uJy

Unbiased star formation rates in z~2 sBzK

VLA 1.4GHz stacking: 30,000 in COSMOS

COSMOS 2 deg2 Deep Field (Scoville ea)

• Approaching SDSS volume at z > 1

• 2e6 galaxies from z~ 0 to 7

(Decarli)

SFR ~ independent of blue magnitude

SFR increases with B-z => dust extinction increases with SFR (or M*)

SFR increases with stellar mass

Stacking in bins of 30001010 Mo 3x1011 Mo

Dawn of Downsizing: SFR/M* vs. M* (Karim)

5x

tH-1 (z=1.8)

z=0.3

1.4GHz SSFR

z=1.5

z=2.1

UV SSFR

SSFR constant with M*, unlike z<1=> ‘pre-downsizing’ ~ constant efolding time

z>1.5 sBzK well above the ‘red and dead’ galaxy line => even large growing exponentially

UV dust correction = f(SFR, M*) [factor 5 at 2e10 Mo ~ LBG (Shapely+ 01)]

CO observations with Bure: Massive gas reservoirs without extreme starbursts (Daddi ea 2009)

6 of 6 sBzK detected in CO

Gas mass ~ 1011 Mo ~ gas masses in high z HyLIRG

but

SFR < 10% HyLIRG

Gas masses ≥ stellar masses => pushed back to epoch when galaxies are gas dominated!

Lower CO excitation: low J observations are key!

FIR/L’CO: Gas consumption timescales >= few x108 yrs

HyLIRG

Closer to Milky Way-type gas conditions (Dannerbauer)

1

1.5

Summary Theme II: Probing the Gas Rich Universe = Gas dominated, normal galaxy formation at z ~2

SSFR constant with M*: ‘pre-downsizing’

Well above ‘red + dead’ curve up to 1011 M*

Gas masses ~ 1011 Mo ≥ stellar masses

Gas consumption time > few x108 yrs

‘Secular (spiral) galaxy formation during epoch of galaxy assembly’

Great promise for ALMA + EVLA!

Genzel + 08

What is the EVLA? similar ten-fold improvement in most areas of cm astronomy

•frequencies = 1 to 50 GHz

•8 GHz BW => 80x old

•res = 40mas res at 43GHz

•rms = 6uJy in 1hr at 30GHz

What is ALMA? Tenfold improvement (or more), in all areas of (sub)mm astronomy, including resolution, sensitivity, and frequency coverage.

•antennas: 54x12m, 12x7m antennas

•frequencies: 80 GHz to 720 GHz

•res = 20mas res at 700 GHz

•rms = 13uJy in 1hr at 230GHz

ALMA+EVLA ~ Order magnitude improvement from 1GHz to 1 THz!

(Testi)

(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

100 Mo yr-1 at z=5

Pushing to normal galaxies

EVLA 1.4 GHz continuum: thousands of sBzK galaxies

ALMA and first galaxies: [CII]

100Mo/yr

10Mo/yr

ALMA ‘redshift machine’: [CII] in z>7 dropouts

Wide bandwidth spectroscopy

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

• 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

EVLA Status

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

•Early science in March 2010 using new correlator (2GHz)

•Full receiver complement completed 2012 + 8GHz

5 antennas on high site

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

0.4mJy

1000 km/s

0.3mJy

• SFR ~ 103 Mo/year

• Mgas ~ 1011 Mo

• Early, clustered massive galaxy formation

+250 km/s

-250 km/s

Dense gas history of the Universe Tracing the fuel for galaxy formation over cosmic time

Millennium Simulations Obreschkow & Rawlings

SF Law

Primary goal for studies of galaxy formation in next decade!

SFR

Mgas

EVLA/ALMA Deep fields: the‘missing half’ of galaxy formation

• 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

Millennium Simulations Obreschkow & Rawlings

ESO

END

CCAT: wide field ‘finder’ surveys