ESO

The other side of galaxy formation: radio line and continuum ‘Great Surveys’

Santa Fe November 2008Chris Carilli

NRAO

Cosmological deep fields: COSMOS

o Definitive study of galaxy and SMBG evolution vs. environmnent

o ACS: 600 orbits for 2deg2 to IAB = 26

o VLA, Spitzer, 11-band SUBARU++, Galex, Chandra/XMM

o Similar to SDSS in volume and resolution but at z > 1

o 2e6 galaxies from z~ 0 to 7

Star formation rate density vs. redshift

‘epoch of galaxy assembly’

Next level of detail: galaxy formation as function of M*

‘specific star formation rates’ = SFR/M*

‘Downsizing’

tH-1

‘active star formation’

‘red and dead’

Zheng+

Star formation history of Universe: dirty little secret

UV correction factor ~ 5x

Optical limitations

Dust obscuration: missing earliest, most active phases of galaxy formation

Only stars and star formation: not (cold) gas => missing the other half of the problem = ‘fuel for galaxy formation’

Radio astronomy: unveiling the cold, obscured universe

Wilson et al.

HST / OVRO CO

mm continuum: thermal emission from warm dust = star formation (see Yun)

(sub)mm lines: molecular gas, fine structure ISM cooling lines

(short) cm lines: low order molecular transitions, dynamics

cm continuum: synchrotron emission = star formation

(long) cm lines: HI 21cm (see Henning)

850um Class 0 protostar

COSMOS VLA deep

16x16x

Full field at 1.4GHz

1.5” resolution

rms ~ 8 uJy/beam

4000 sources (10xHUDF)

(mostly) star forming galaxies

9

10

11

12

13

14

Log

(FI

R L

um

inosi

ty)

ULIRGs~Arp220 SFR ~ 100 Mo/yrLIRGs~ M82 SFR~ 10 Mo/yr

AGN or

Radio Surveys - LimitsRadio Surveys - Limits

Milky Way SFR ~ 1 Mo/yr

40uJy

Submm gals: SFR > 103 Mo yr-1

Pushing uJy radio studies to z>2: Stacking Cosmos BzK, LBG and LAE

Median stacking of high-z ‘dropout’ samples in Cosmos field• 30,000 BzK at z~1.3 to 2.5• 8500 LBGs (U,B,V dropouts) at z~ 3, 4, 5• 100 LAE in NB850 at z = 5.7• ‘normal’ star forming galaxy populations at high redshift• Stacking analysis: ~ sub-uJy limits

4000A

Ly-break

BzK at z=1.7

30,000 sBzK galaxies in Cosmos (>5x previous): Pannella+

star forming

nearIR selected: KAB ~ 23

M* ~ 1010 to 1011 Mo

HST sizes ~ 1” ~ 9kpc

Photo z

z~1.3 to 2.5

Density ~ few x10-4 Mpc-3 ~ 30x SMG

Forming ‘normal’ ellipticals, large spirals?

3.2”

Daddi, McCracken +

HST

2e10 3e11

VLA stack 30,000 sBzK

Pannella +

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

=> <SFR> ~ 96 Mo yr-1 < 0.1x SMG

Size ~ 1”

SKA (sub-uJy) science before the SKA

S1.4 increases with M* => SFR increases with stellar mass

S1.4 increases with B-z => dust extinction increases with SFR (or M*)

Stacking in bins of 40001010 Mo 3x1011 Mo

Dawn of Downsizing: SFR/M* vs. M*

5x

tH-1 (z=1.8)

z=0.3

1.4GHz SSFR

z=1.5

z=2.1

UV SSFR

SSFR increases with z

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

z>1.5 sBzK well above the ‘red and dead’ galaxy line

Extinction increases with SFR, M*

<factor 5> UV dust correction needs to be differential wrt SFR, M*

Great Surveys: next gen radio deep fields

Arcsec resolution is required to avoid confusion and detect ‘normal’ star forming galaxies at z > 1.5

All confusion limited (res>5”)

Early Universe Molecular Line Galaxies

Submm galaxies: z ~ 1.5 to 4.5

SDSS J1335+3533 z=6.04

Gas mass (H2)~ 1010 to 1011 Mo (~ 10 to 100x MW)

FIR > 1013 Lo => Star formation rates > 103 Mo yr-1

Giant elliptical galaxy formation at high redshift?

COSMOS J1000+0234 z=4.52

Most distant SMG

QSO host galaxies: z ~ 1 to 6.4

• SMBH ~ 1e9 Mo

• Dust mass ~ 7e8 Mo

• Gas mass ~ 2e10 Mo

• CO size ~ 6 kpc• Dynamical Mass ~ 4e10 Mo

Gas, Dust, Star Form, in host galaxy of J1148+5251 z=6.42

Only direct observations of host galaxy properties

1”

FIR excess -- SED consistent with starburst: SFR ~ 3000 Mo/yr

CO excitation ~ starburst nucleus: Tkin ~ 100K, nH2 ~ 1e5 cm-3

Radio-FIR correlation

50KElvis QSO SED

Continuum SED and CO excitation: ISM physics at z=6.42

NGC253

MW

Building giant elliptical galaxies + SMBHs at tuniv < 1Gyr

z=6 QSO host stats (33 total)

10.5

8.1

6.5

Li, Hernquist, Roberston..

z=10

10 in dust: FIR > 1e13 Lo

5 in CO: Mgas > 1e10 Mo

10 at 1.4 GHz continuum

2 in [CII]

=> SFR > 103 Mo yr-1

• Rapid enrichment of metals, dust, molecules

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

LFIR vs L’(CO) ~ SFR vs. total gas mass

Integrated Schmidt-Kennicutt Law

High-z sources = 10 -- 100 x Mgas of Milky WayIndex=1.5

Low z

tdep~3e8 yr

Current sens ~ few x1010 Mo

1e3 Mo/yr

High z

tdep~1e7 yr

• Star formation efficiency = SFR per unit gas mass, increases with increasing SFR

• Gas depletion timescale = Mgas/SFR decreases with SFR

SFR

Gas Mass

sBzK: not extreme starbursts, but massive gas reservoirs

6 of 6 sBzK detected in CO with Bure

Gas mass > 1010 Mo ~ submm galaxies, but

SFR < 10% submm gal

5 arcmin-2 (~50x submm galaxies)

Daddi + 2008

Excitation = Milky Way (not starburst)

FIR/L’CO = spiral (not starburst)

Extreme gas rich galaxies without extreme starbursts

Gas depletion timescales > 5 x108 yrs

Starburst

Dannerbauer + Daddi +

sBzK

Low z ellipt

??

Current limitation: CO search requires optical pre-selection

Mgas >~ M*

Great Surveys: blind molecular line ‘piggy back’ surveys using 8GHz bandwidth

EVLA: CO 1-0 at z = 1.4 to 1.9 (48 to 40 GHz)

FoV ~ 1 arcmin2 => ~ 2 or 3 sBzK (M* > 1010 Mo)

rms (10hr, 300 km/s) = 50 uJy => L’(CO) = 1.9e9 K km/s pc2

4 mass limit: M(H2) = 3x1010 Mo (Galactic X factor)

=> Every ‘Q-band’ full synthesis will have ~ 1 sBzK CO detection

ALMA: CO 2-1 at z = 1.45 to 1.7 (93 to 85 GHz)

FoV ~ 1 arcmin2 , but fractional BW (z) ~ 1/2 EVLA

S2-1 ~ 4xS1-0 (in Jy) and rms (300 km/s) ~ 30uJy

Mass limit ~ 5x109 Mo

=> Every ‘Band 3’ full synthesis will have ~ 3 sBzK CO detections

What is EVLA? First steps to the SKABy 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 BW (8GHz)

• Antenna retrofits now 50% completed.• Early science Q1 2010, using new correlator. • Full receiver complement completed 2012.

AOS Technical Building

Array operations center

What is ALMA?International collaboration to build & operate largest millimeter/submm array at 5000m in northern Chile -> order of magnitude, or more, improvement in all areas of (sub)mm astronomy, including resolution, sensitivity, and frequency coverage.

Antenna commissioning in progress

•Antennas, receivers, correlator in production: best (sub)mm receivers and antennas ever!•Site construction well under way: Observation Support Facility, Array Operations Site, antenna pads•North American ALMA Science Center (C’Ville): support early science Q4 2010, full ops Q4 2012

ESO

END