What is EVLA Giant steps to the SKAhigh

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What is EVLA? Giant steps to the SKA-high
By building on the existing infrastructure,
replace 1970s electronics gt multiply 10 to
100-fold the VLAs observational capabilities
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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

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Star formation rate density vs. redshift
z 1 to 3 epoch of galaxy assembly 50 of
stellar mass forms
zgt6 First light cosmic reionization
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Star formation as function of galaxy stellar mass
active star formation
specific SFR SFR/M
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tH-1
red and dead
Downsizing
1011
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)

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Galaxy formation optical limitations

• 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 gt
  missing the other half of the problem fuel for
  galaxy formation

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Obscuration-free SFR during epoch of galaxy
assembly VLA observations of Cosmos

• Full 2 deg2 at 1.4GHz
• 1.5 resolution
• rms 10 uJy/beam
• 4000 sources (10xHUDF)

Mostly SF gal at z lt 1 AGN, or extreme starburst
at zgt1 SFR gt 1000 Mo yr-1
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Cosmos 30,000 normal star forming galaxies
(sBzK) during epoch of galaxy assembly (zphot
1.3 to 2.6)

• Common few x10-4 Mpc-3 (5arcmin-2)
• M 1010 to 1011 Mo
• HST sizes 1 7kpc
• clump-cluster/chain galaxies (Elmegreen et
  al. 2007)
• Ha IFU imaging gt clumps star forming regions
  in smoothly rotating, turbulent disk (Genzel et
  al. 2008)

HST
2
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VLA radio stacking 30,000 sBzK in Cosmos

• ltSFRgt 96 Mo yr-1 FIR 3e11 Lo
• VLA size 1 HST
• Who needs the SKA?!

ltS1.4gt 8.8 /- 0.1 uJy
Pannella
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Stacking in bins of 3000
1010 Mo
3x1011 Mo

• SFR independent of blue magnitude
• SFR increases with B-z gt dust extinction
  increases with SFR (or M)
• SFR increases with stellar mass

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Dawn of Downsizing SFR/M vs. M
1.4GHz SSFR

• SSFR constant with M, unlike zlt1gt
  pre-downsizing
• zgt1.5 sBzK well above the red and dead galaxy
  line
• UV dust correction f(SFR, M) factor 5 at
  2e10 Mo LBG

z2.1
z1.5
5x
tH-1 (z1.8)
z0.3
UV SSFR
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1.4 GHz uJy source counts (Bondi et al. 07)
EVLA sBzK

• 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

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CO observations of sBzK galaxies with Bure
Massive gas reservoirs Daddi 2009

• 6 of 6 sBzK detected in CO
• Gas mass 1011 Mo
• Gas masses stellar masses gt early
  evolutionary phase

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VLABure gt Milky Way conditions excitation,
FIR/LCO
HyLIRG
1.5
Daddi
Dannerbauer
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First studies of normal galaxies during the
dominant epoch of star formation in the Universe

• Mgas M gt early evolutionary phase
• MW conditions gt Gas depletion timescales gt few
  x108 yrs
• SSFR gt Active star formation over wide range in
  M

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GN20 proto-cluster at z4.05 A unique laboratory
for studying massive galaxy formation within 2Gyr
of Big Bang

• SMG group GN20, GN20.2a,b LFIR 1013 Lo gt SFR
  gt 1000 Mo 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)

GN20.2b
CO1-0 VLA
CO 6-5 Bure
GN20.2a
GN20
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HST, CO2-1, FIR

• GN20 Merger or cold mode accretion?
• Highly obscured in optical
• Big 10kpc CO ring/disk
• Resolved clumps 1kpc (TB 15K)
• Rotation ?v 900 km/s

CO2-1 0.45
CO2-1 0.15
10kpc
CO6-5
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Gas density history of the Universe EVLANoema CO
deep fields
Bell
H2 mass function
z0
SF law
z4

• Unbiased survey for cold gas EVLA survey of
  1.4e5 Mpc3
• 1000hrs, 50 arcmin2, ?obs 30 to 38GHz, down
  to 0.15 res.
• z 2 to 2.8 in CO 1-0 CO 2-1 z5 to 6.7
• Expect 300 galaxies with M(H2) gt 2e1010 Mo

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Correlator Receiver Availability Timescale
Today
VLA Correlator
WIDAR Correlator
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• EVLA Status
• Early science Q1,2 2010
• complete18-50GHz (still can use old Rx lt20GHz)
• WIDAR with up to 2GHz
• Resident shared risk proposal deadline
  Tomorrow!
• 8GHz available 2011
• Full receiver complement completed 2012.