What is EVLA? Giant steps to the SKA-high ParameterVLAEVLAFactor Point Source Sensitivity (1- , 12 hr.)10  Jy1  Jy 10 Maximum BW in each polarization0.1 GHz 8 GHz80 # of frequency channels at max. BW1616, Maximum number of freq. channels5124,194, (Log) Frequency Coverage (1 – 50 GHz)22%100%5 By building on the existing infrastructure, replace 1970’s electronics => multiply 10 to 100-fold the VLA’s observational capabilities

VLA + IRAM studies of galaxy formation VLA Radio continuum = star formation Low order CO = total gas mass, dynamics Dense molecular gas tracers Resolution down to 0.1” Bure/30m Dust = star formation High order CO = gas excitation, ISM physics Atomic FS Lines = gas cooling Resolution down to 0.3”

Star formation rate density vs. redshift z ~ 1 to 3: ‘epoch of galaxy assembly’ ~50% of stellar mass forms z>6: First light + cosmic reionization

Star formation as function of galaxy stellar mass ‘Downsizing’ t H -1 ‘active star formation’ ‘red and dead’ Eg. Zheng, Noeske, Damen…  Massive galaxies form most of their stars at high z (see also: stellar pop. synthesis at low z; evolved galaxies at z ~1 to 2) specific SFR = SFR/M *

Galaxy formation: optical limitations UV correction factor ~ 5x  Dust obscuration: rest frame UV needs substantial dust- correction, missing earliest, most intense epochs of star formation  Only stars and star formation: not (cold) gas => missing the other half of the problem = ‘fuel for galaxy formation’

Obscuration-free SFR during epoch of galaxy assembly VLA observations of Cosmos  Full 2 deg 2 at 1.4GHz  1.5” resolution  rms ~ 10 uJy/beam  4000 sources (10xHUDF) Mostly SF gal at z < 1 AGN, or extreme starburst at z>1: SFR > 1000 M o yr -1

2” HST  Common ~ few x10 -4 Mpc -3 (5arcmin -2 )  M * ~ to M o  HST sizes ~ 1” ~ 7kpc  ‘clump-cluster’/’chain’ galaxies (Elmegreen et al. 2007)  Hα IFU imaging => clumps = star forming regions in smoothly rotating, turbulent disk (Genzel et al. 2008) Cosmos: 30,000 normal star forming galaxies (‘sBzK’) during epoch of galaxy assembly (z phot = 1.3 to 2.6)

 = 96 M o yr -1 [FIR ~ 3e11 L o ]  VLA size ~ 1” ~ HST [Who needs the SKA?!] = 8.8 +/- 0.1 uJy VLA radio stacking: 30,000 sBzK in Cosmos Pannella +

 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 M o 3x10 11 M o

Dawn of Downsizing: SFR/M * vs. M * 5x t H -1 (z=1.8) z= GHz SSFR z=1.5 z=2.1 UV SSFR  SSFR constant with M *, unlike z ‘pre-downsizing’  z>1.5 sBzK well above the ‘red and dead’ galaxy line  UV dust correction = f(SFR, M * ) [factor 5 at 2e10 M o ~ LBG]

1.4 GHz uJy source counts (Bondi et al. 07) Flattening below 1mJy = star forming galaxies at intermediate z Expect large population of z ~ 1 to 3 normal star forming galaxies (eg. sBzK ~ 5 arcmin -2 ) in EVLA deep field rms ~ 1 uJy EVLA ~ sBzK

CO observations of sBzK galaxies with Bure: Massive gas reservoirs Daddi  6 of 6 sBzK detected in CO  Gas mass ~ M o  Gas masses ≥ stellar masses => early evolutionary phase

VLA+Bure => Milky Way conditions: excitation, FIR/L’CO HyLIRG Dannerbauer + Daddi + First studies of normal galaxies during the dominant epoch of star formation in the Universe M gas ≥ M * => early evolutionary phase MW conditions => Gas depletion timescales > few x10 8 yrs SSFR => Active star formation over wide range in M *

GN20 proto-cluster at z=4.05: A unique laboratory for studying massive galaxy formation within 2Gyr of Big Bang  SMG group GN20, GN20.2a,b: L FIR ~ L o => SFR > 1000 M o yr -1  15 LBGs at z ~ 4.06+/-0.02, within 1’ = 6x over-density  Detected CO1-0, 2-1, 4-3, 5-4, 6-5, (7-6) CO1-0 VLA CO 6-5 Bure GN20 GN20.2b GN20.2a

CO ” CO ” HST, CO2-1, FIR GN20: Merger or cold mode accretion?  Highly obscured in optical  Big: 10kpc CO ring/disk  Resolved clumps ~ 1kpc (T B ~ 15K)  Rotation: Δv = 900 km/s 10kpc CO6-5

Gas density history of the Universe EVLA+Noema CO deep fields Unbiased survey for cold gas: EVLA survey of 1.4e5 Mpc 3  1000hrs, 50 arcmin 2, ν obs = 30 to 38GHz, down to 0.15” res.  z = 2 to 2.8 in CO 1-0 [CO 2-1 z=5 to 6.7]  Expect ~ 300 galaxies with M(H 2 ) > 2e10 10 M o Bell + SF law H 2 mass function z=0 z=4

17 Correlator + Receiver Availability Timescale VLA CorrelatorWIDAR Correlator Today

EVLA Status Early science: Q1,  complete18-50GHz (still can use old Rx <20GHz)  WIDAR with up to 2GHz  Resident shared risk proposal deadline: Tomorrow! 8GHz available 2011 Full receiver complement completed 2012.