ESO ALMA, EVLA, and the Origin of Galaxies (Dense Gas History of the Universe) Chris Carilli (NRAO)...
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Transcript of ESO ALMA, EVLA, and the Origin of Galaxies (Dense Gas History of the Universe) Chris Carilli (NRAO)...
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