Download LANL Cosmology Summer School Lectures, July 2010

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Astronomical spectroscopy wikipedia, lookup

Microplasma wikipedia, lookup

Cosmic distance ladder wikipedia, lookup

Gravitational lens wikipedia, lookup

Stellar evolution wikipedia, lookup

Star formation wikipedia, lookup

High-velocity cloud wikipedia, lookup

H II region wikipedia, lookup

Weak gravitational lensing wikipedia, lookup

Astrophysical X-ray source wikipedia, lookup

Transcript
Radio observations of the formation of the
first galaxies and supermassive Black Holes
Chris Carilli (NRAO)
LANL Cosmology School, July 2010
• Concepts and tools in radio astronomy: dust, cool gas, and star
formation
• Quasar host galaxies at z=6: coeval formation of massive galaxies
and SMBH within 1 Gyr of the Big Bang
• Quasar near-zones and reionization
•Bright future: pushing to normal galaxies with the Atacama Large
Millimeter Array and Expanded Very Large Array – recent examples!
ESO
Collaborators: R.Wang, D. Riechers, Walter, Fan, Bertoldi, Menten,
Cox, Strauss, Neri
Millimeter through centimeter astronomy: unveiling the cold,
obscured universe
optical
mid-IR
CO
Submm = dust
Galactic
GN20 SMG z=4.0
• optical studies provide a limited view of
star and galaxy formation
• cm/mm reveal the dust-obscured, earliest,
most active phases of star and galaxy
formation
HST/CO/SUBMM
Cosmic ‘Background’ Radiation
30 nW m-2 sr-1
17 nW m-2 sr-1
Over half the light in the
Universe is absorbed by
dust and reemitted in the
FIR
Franceschini 2000
Radio – FIR: obscuration-free estimate of massive star formation
 Radio: SFR = 1x10-21 L1.4 W/Hz
 FIR:
SFR = 3x10-10 LFIR (Lo)
Magic of (sub)mm: distance independent method of
studying objects in universe from z=0.8 to 10
LFIR ~ 4e12 x S250(mJy) Lo
SFR ~ 1e3 x S250 Mo/yr
FIR = 1.6e12 L_sun
1000 Mo/yr
obs = 250 GHz
7
Spectral lines
cm
submm
z=0.2
Atomic fine
structure lines
Molecular rotational
lines
z=4
Molecular gas
 CO = total gas masses = fuel
for star formation
M(H2) = α L’(CO(1-0))
 Velocities => dynamical
masses
 Gas excitation => ISM physics
(densities, temperatures)
 Dense gas tracers (eg. HCN)
=> gas directly associated with
star formation
 Astrochemistry/biology
Wilson et al.
CO image of ‘Antennae’
merging galaxies
Fine Structure lines
[CII] 158um (2P3/2 - 2P1/2)
 Principal ISM gas coolant:
efficiency of photo-electric
heating by dust grains.
 Traces star formation and the
CNM
Fixsen et al.
[CII] CO
[OI] 63um [CII]
 COBE: [CII] most luminous
cm to FIR line in the Galaxy ~
1% Lgal
 Herschel: revolutionary look at
FSL in nearby Universe –
AGN/star formation diagnostics
[OIII] 88um [CII]
Cormier et al.
[OIII]/[CII]
MAMBO at 30m
Powerful suite of existing
cm/mm facilites
First glimpses into early
galaxy formation
30’ field at 250 GHz
rms < 0.3 mJy
Very Large Array
Plateau de Bure Interferometer
30’ field at 1.4 GHz
High res imaging at 90 to 230 GHz
rms< 10uJy, 1” res
rms < 0.1mJy, res < 0.5”
High res imaging at 20 to 50 GHz
rms < 0.1 mJy, res < 0.2”
Massive galaxy and SMBH
formation at z~6: gas, dust,
star formation in quasar hosts
SDSS
Apache Point NM
Why quasars?
 Rapidly increasing samples:
z>4: > 1000 known
z>5: > 100
z>6: 20
 Spectroscopic redshifts
 Extreme (massive) systems
MB < -26 =>
Lbol > 1014 Lo
MBH > 109 Mo (Eddington / MgII)
1148+5251
z=6.42
6.4
Gunn-Peterson
Effect
SDSS z~6 quasars => tailend of reionization and
first (new) light?
z=6.4
5.7
QSO host galaxies
MBH – Mbulge relation
Nearby galaxies
Haaring & Rix
 All low z spheroidal galaxies have SMBH: MBH=0.002 Mbulge
‘Causal connection between SMBH and spheroidal galaxy formation’
 Luminous high z quasars have massive host galaxies (1012 Mo)
Cosmic Downsizing
Massive galaxies form most of their stars rapidly at high z
~(e-folding time)-1
Currently active
star formation
tH-1
Red and dead =>
Require active star
formation at early
times
Zheng+
• Massive old galaxies at high z
• Stellar population synthesis in nearby ellipticals
Dust in high z quasar host galaxies: 250 GHz surveys
HyLIRG
Wang sample 33
z>5.7 quasars
• 30% of z>2 quasars have S250 > 2mJy
• 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)
 ‘Smoking quasars’: dust formed
in BLR winds (Elvis)
SMC, z<4 quasars
Galactic
z~6 quasar, GRBs
 ISM dust formation (Draine)
• Extinction toward z=6.2 QSO
and z~6 GRBs => different
mean grain properties at z>4
(Perley, Stratta)
 Larger, silicate + amorphous
carbon dust grains formed in core
collapse SNe vs. eg. graphite
Stratta et al.
Dust heating? Radio to
near-IR SED
 FIR excess = 47K dust
 SED consistent with star
forming galaxy:
SFR ~ 400 to 2000 Mo yr-1
low z SED
TD = 47 K
TD ~ 1000K
Star formation?
AGN
Radio-FIR correlation
Fuel for star formation? Molecular gas: 8 CO detections at
z ~ 6 with PdBI, VLA
1mJy
• M(H2) ~ 0.7 to 3 x1010 (α/0.8) Mo
• Δv = 200 to 800 km/s
CO excitation: Dense, warm gas, thermally excited to 6-5
230GHz
691GHz
starburst nucleus
Milky
Way
• 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
LFIR vs L’(CO): ‘integrated Kennicutt-Schmidt star
formation law’
• Further circumstantial
evidence for star formation
SFR
• Gas consumption time
(Mgas/SFR) decreases with SFR
FIR ~ 1010 Lo/yr => tc~108yr
FIR ~ 1013 Lo/yr => tc~107yr
1e3 Mo/yr
Index=1.5
MW
1e11 Mo
Mgas
=> Need gas re-supply to build
giant elliptical
1148+52 z=6.42: VLA imaging at 0.15” resolution
CO3-2 VLA
IRAM
1” ~ 6kpc
+
0.3”
 ‘molecular galaxy’ size ~ 6 kpc – only direct observations of host
galaxy of z~6 quasar!
 Double peaked ~ 2kpc separation, each ~ 1kpc
 TB ~ 35 K ~ starburst nuclei
Gas dynamics => ‘weighing’ the first galaxies
z=6.42
-150 km/s
7kpc
+150 km/s
 CO only method for deriving dynamical masses at these distances
 Dynamical mass (r < 3kpc) ~ 6 x1010 Mo
 M(H2)/Mdyn ~ 0.3
Gas dynamics: CO velocities
-150 km/s
z=4.4
z=4.19
+150 km/s
 Dynamical masses ~ 0.4 to 2 x1011 Mo
 M(H2)/Mdyn ≥ 0.5 => gas/baryons dominate inner few kpc
Break-down of MBH – Mbulge relation at very high z
z>4 QSO CO
z<0.2 QSO CO
Low z galaxies
Riechers +
<MBH/Mbulge> ~ 15 higher at z>4 => Black holes form first?
Wang z=6 sample: galaxy
mass vs. inclination,
assuming all have CO
radii ~ J1148+5251
Wang +
Low z MBH/Mbulge
• Departure from MBH – Mbulge at highest z, or
•All face-on: i < 20o
[CII] 158um search in z > 6.2 quasars
For z>6 => redshifts to 250GHz => Bure!
[CII]
1”
[NII]
•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’
PdBI
250GHz
0.25”res
• [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
[CII]
• [CII]/FIR decreases with
LFIR = lower gas heating
efficiency due to charged
dust grains in high
radiation environments
• Opacity in FIR may also
play role (Papadopoulos)
Malhotra
[CII]
z >4
• HyLIRG at z> 4: large
scatter, but no worse than
low z ULIRG
• Normal star forming
galaxies are not much
harder to detect in [CII]
(eg. LBG, LAE)
Maiolino, Bertoldi, Knudsen,
Iono, Wagg
A starburst to quasar
sequence at the highest z?
Anticorrelation of EW(Lya)
with submm detections
No Dust
Submm dust
• Strong FIR => starburst
• Weak Lya => young quasar, prior to build-up of BLR (?)
• Consistent with ‘Sanders sequence’: starburst to composite to quasar
Submm dust
No Dust
Summary cm/mm observations
of 33 quasars at z~6: only
direct probe of the host galaxies
160uJy
EVLA
J1425+3254 CO at z = 5.9
 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
 3 in [CII] => maximal star forming disk: 1000 Mo yr-1 kpc-2
 Departure from MBH – Mbulge at z~6: BH form first?
 Anticorrel. EW(Lya) with submm detections => SB to Q sequence
10
Extreme Downsizing: Building a
giant elliptical galaxy + SMBH at
tuniv< 1Gyr
 Plausible? 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
6.5
 SMBH of ~ 2e9 Mo forms via
Eddington-limited accretion + mergers
 Evolves into giant elliptical galaxy in
massive cluster (3e15 Mo) by z=0
Li, Hernquist et al.
Li, Hernquist+
• 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 z > 6
BREAK
Discussion points:
1.Dust formation within 1Gyr of Big Bang?
2.Evolution of MBH – Mbulge relation?
3.Starburst to quasar sequence: duty cycles and
timescales?
4.Gas resupply (CMA, mergers)?
5.FIR – EW(Lya) anti-correlation?
ESO
Quasar Near Zones: J1148+5251
• Accurate host galaxy redshift from CO: z=6.419
• Quasar spectrum => photons leaking down to z=6.32
White et al. 2003
• ‘time bounded’ Stromgren sphere ionized by quasar
• Difference in zhost and zGP =>
RNZ = 4.7Mpc
[fHI Nγ tQ]1/3 (1+z)-1
HI
HII
Loeb & Barkana
Quasar Near-Zones: sample of 25 quasars at z=5.7 to 6.5
(Carilli et al. 2010)
I.Host galaxy redshifts: CO (6), MgII (11), UV (8)
I.GP on-set redshift:
•Adopt fixed resolution of 20A
•Find 1st point when transmission drops below 10% (of extrapolated) = well
above typical GP level.
z = 6.1
Wyithe et al. 2010
Quasar Near-Zones: Correlation of RNZ with UV luminosity
Nγ1/3
LUV
Quasar Near-Zones: RNZ vs redshift
RNZ = 7.3 – 6.5(z-6)
z>6.15
•<RNZ> decreases by factor 2.3 from z=5.7 to 6.5 =>
fHI increases by factor 9
• Pushing into tail-end of reionization?
Alternative hypothesis to Stromgren sphere: Quasar Proximity
Zones (Bolton & Wyithe)
• RNZ measures where density of ionizing photon from quasar >
background photons (IGRF) =>
RNZ
[Nγ]1/2 (1+z)-9/4
• Increase in RNZ from z=6.5 to 5.7 is then
due to rapid increase in mfp and density of
ionizing background during overlap or
‘percolation’ stage of reionization
• Either case (CSS or PZ) => rapid
evolution of IGM from z ~ 6 to 6.5
What is Atacama Large Milllimeter Array?
North American, European, Japanese, and Chilean collaboration to build &
operate a large millimeter/submm array at high altitude site (5000m) in
northern Chile => order of magnitude, or more, improvement in all areas of
(sub)mm astronomy, including resolution, sensitivity, and frequency coverage.
ALMA Specs
• High sensitivity array = 54x12m
• Wide field imaging array = 12x7m antennas
• Frequencies = 80 GHz to 720 GHz
• Resolution = 20mas res at 700 GHz
• Sensitivity = 13uJy in 1hr at 230GHz
What is EVLA? First steps to the SKA-high
By 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 Bandwidth (8GHz) + 104 channels
 40mas resolution at 40GHz
Overall: ALMA+EVLA provide > order magnitude
improvement from 1GHz to 1 THz!
Pushing to normal galaxies: spectral lines
100 Mo yr-1 at z=5
cm telescopes: star formation, low
order molecular transitions -- total
gas mass, dense gas tracers
(sub)mm: dust, high order
molecular lines, fine
structure lines -- ISM
physics, dynamics
ALMA and first galaxies: [CII] and Dust
100Mo/yr
10Mo/yr
Wide bandwidth spectroscopy
J1148+52 at z=6.4 in
24hrs with ALMA
• ALMA: Detect multiple lines, molecules per 8GHz band
• 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
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
embargoed
first light image
EVLA Status
• Antenna retrofits 70% complete (100% at ν ≥ 18GHz).
• Full receiver complement completed 2012 with 8GHz bandwidth
• Early science started March 2010 using new correlator (up to 2GHz
bandwidth) – already revolutionizing our view of galaxy formation!
GN20 molecule-rich proto-cluster at z=4
CO 2-1 in 3 submm galaxies, all in 256 MHz band
0.3mJy
z=4.055
4.051
4.056
0.7mJy
CO2-1
46GHz
0.4mJy
• SFR ~ 103 Mo/year
• Mgas > 1010 Mo
• Early, clustered massive
galaxy formation
1000 km/s
GN20 z=4.0
VLA: ‘pseudo-continuum’
2x50MHz channels
EVLA: well sampled velocity field
GN20 moment images
+250 km/s
-250 km/s
• Low order CO emitting regions are large (10 to 20 kpc)
• Gas mass = 1.3e11 Mo
• Stellar mass = 2.3e11 Mo
• Dynamical mass (R < 4kpc) = 3e11 Mo
=> Baryon dominated within 4kpc
Most distant SMG: z=5.3 (Riechers et al)
EVLA
Bure
CO excitation => ISM conditions
• nH2 ~ 104.3 cm-3
• TK ~ 45 K
CO 1-0 in normal galaxies at z=1.5 (‘sBzK’ galaxies)
Bure 2-1
HST
EVLA 1-0
4”
0.3mJy
500 km/s
• SFR ~ 10 to 100 Mo/year
• Find: MH2 > 1010 Mo> Mstars => early stage of MWtype galaxy formation?
• Again: low order CO is big (28kpc)
• Milky Way-like CO excitation (low order key!)
•10x more numerous than SMGs
Dense gas history of the Universe: the ‘other half’ of galaxy formation
 Tracing the fuel for galaxy formation over cosmic time
Millennium Simulations
Obreschkow & Rawlingn
SF law
Major observational goal for next decade
EVLA/ALMA Deep fields: 1000hr, 50 arcmin2
• 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
END
Discussion points
1.Stromgren spheres vs. Proximity zones?
2.DGHU, star formation laws, and CO to H2
conversion factors?
3.Role of EVLA/ALMA in first galaxy studies?
Pushing to normal galaxies: continuum
A Panchromatic view of 1st galaxy formation
100 Mo yr-1 at z=5
cm: Star formation,
AGN
(sub)mm Dust,
FSL, mol. gas
Near-IR: Stars,
ionized gas, AGN
Comparison to low z quasar hosts
z=6 quasars
IRAS selected
Stacked mm
non-detections
PG quasars
Hao et al. 2005
Molecular gas mass: X factor
M(H2) = X L’(CO(1-0))
Milky way: X = 4.6 MO/(K km/s pc^2) (virialized GMCs)
ULIRGs: X = 0.8 MO/(K km/s pc^2) (CO rotation curves)
 Optically thin limit: X ~ 0.2
Downes + Solomon
Milky Way-type gas conditions
Mgas
HyLIRG
1.5
Dannerbauer +
1
Daddi +
SFR
 CO excitation = Milky Way (but mass > 10xMW)
 FIR/L’CO  Milky Way
 Gas depletion timescales > few x108 yrs
Building a giant elliptical galaxy + SMBH at tuniv< 1Gyr
10
• Rapid enrichment of metals, dust in ISM
• Rare, extreme mass objects: ~ 100 SDSS z~6 QSOs on entire sky
Issues and questions:
• Duty cycle for star formation and SMBH accretion very
6.5 high?
• Gas resupply: not enough to build GE
• Goal: push to normal galaxies at z > 6Li,
Issues
Hernquist et al.
Quasar Near-Zones
Nγ1/3
LUV
• Correlation of RNZ with UV luminosity
• No correlation of UV luminosity with redshift