High Frequency (> 10GHz)

Thermal science at centimeter wavelengths, and more!

Chicago III, Sept. 15, 2007

Washington DC

Chris Carilli (NRAO)

Laundry list of high frequency science with SKA

(what we lose without >10GHz)

• First light: molecular line studies of the first galaxies**

• Cradle of life: Terrestrial planet formation and pre-biotic molecules

• Cosmology: Extragalactic water masers and measurement of Ho

• Testing GR: Pulsars in the Galactic Center

• SZ effect at 30GHz

• Molecular abs line systems and the variation of the fundamental constants

• Stellar masers (SiO, H2O) -- late stages of stellar evolution

• NH3

• Solar system thermal objects: atmospheres, surfaces, asteroids, KBO, comets

• Spacecraft tracking and telemetry at 32GHz: movies from Mars

• Stellar photospheres, winds, outflows

• FF/RRL -- HII regions, SuperStarClusters ….

**Key Science Projects

ALMA/EVLA CO redshift coverageEpoch of Reionization:Benchmark indicating formation first luminous Objects = Last frontier

First galaxies: standard molecular transitions redshift to cm regime

•Total gas mass

•Gas dynamics

•Gas excitation

•High density gas tracers

CO Excitation

ladder

Weiss, Walter, Downes, Henkel, in prep.

ALM

A z

~1

0

Starbursts

Normal galaxies

^2

First galaxies -- Radio astronomy into cosmic reionization

z ~ 6 QSO host galaxies: molecular gas and dust

• Giant reservoirs of molecular gas ~2e10 Mo = fuel for star formation.

• Currently: 2 solid detections, 2 likely at z~6

FWHM=350 km/s

z=6.42

Radio-FIR correlation

50K

Mdust ~ 1e8 Mo

Dust heating: star formation or AGN?

Follows Radio-FIR correlation: SFR ~ 3000 Mo/yr

VLA

PdBI

J1148+52: VLA imaging of CO3-2

Separation = 0.3” = 1.7 kpc

TB = 20K => Typical of starburst nuclei

rms=50uJy at 47GHz

Not just circumnuclear disk.

Can AGN heat dust kpc-scales (geometry/rad transfer)?

1” 5.5kpc

0.4”res

0.15” res

VLA imaging of gas at subkpc resolution

Gas dynamics: Potential for testing MBH - Mbulge relation at high z -- only direct probe of host galaxies

Mdyn~ 2e10/(sin)^2 Mo

Mgas~ 2e10 Mo

Mbulge ~1e12 Mo (predicted)

1148+5251 z=6.42

z<0.5

MBH = 0.002 Mbulge

[CII] 158um ISM gas cooling line at z=6.4 30m 256GHz

Maiolino etal

CII PdBI Walter et al.

C+ = workhorse line for z>6 galaxies with ALMA

Structure identical to CO 3-2” (~ 5 kpc) => distributed gas heating = star formation?

SFR ~ 6.5e-6 L[CII] ~ 3000 Mo/yr

1”

CII + CO 3-2

Higher Density (>1e4 cm^-3) Tracers: HCN, CN, & HCO+,

HCO+ 1-0

•Cloverleaf (z=2.56) = SgrB2 of distant galaxies•Lines 5-10x fainter than CO•ncr > 1e7cm^-3 for higher orders => higher order not (generally) excited?•Dense gas tracers best studied with cm telescopes

HCN 1-0

200uJy

Riechers

CO vs. HCN: total vs. dense gas

Index = 1

HCN traces dense gas (> 1e4 cm^-3)

SFR / dense gas mass ~ universal in all galaxies: ‘Counting star forming clouds’

Index=1.5

• CO traces all molecular gas (>100 cm^-3)

• SFR / total gas mass = star formation efficiency, increases with FIR luminosity.

FIR

L’(CO) L’(HCN)

1e13

1e9

Building a giant elliptical galaxy + SMBH at tuniv < 1Gyr

Multi-scale simulation isolating most

massive halo in 3 Gpc^3 (co-mov)

Stellar mass ~ 1e12 Mo forms in series (7) of major, gas rich mergers from z~14, with SFR ~ 1e3 - 1e4 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

10.5

8.1

6.5

Li, Hernquist, Roberston..

• Enrichment of heavy elements, dust starts early (z > 8): good news for radio astronomy

• Extreme and rare objects: ~ 100 SDSS z~6 QSOs on entire sky

• Integration times of hours to days to detect HyLIGRs

10

(sub)mm: high order molecular lines + fine structure lines

cm telescopes: low order molecular transitions

The need for collecting area: pushing to normal galaxies at high redshift -- spectral lines

cm: Star formation, AGN

(sub)mm Dust, molecular gas

Near-IR: Stars, ionized gas, AGN

Arp 220 vs z

The need for collecting area: continuum

A Panchromatic view of galaxy formation

Bryden 1999

The Cradle of Life (Wilner)

• image terrestrial planet formation zone of disks– grain growth to pebbles

– embedded protoplanets and sub-AU tidal gaps

– Evolution ~ 1 year

• assess biomolecules– disk abundances

– locations

Remijan et al. 2006Remijan et al. 2006

• T Tauri, Herbig Ae stars: several l00’s of proto-Sun analogs, d ~ 140 pc, age 1-10 Myr

– How do terrestrial planets form? – How much orbital evolution (migration)? – Is our Solar System architecture typical?

• SKA: unique probe of disk habitable zone– mas resolution: 1AU = 7mas at 140pc– cm waves: avoid dust opacity– very high sensitivity: thermal emission

• Complementarity – ALMA: Chemistry, dynamics, dust on larger scales– Optical: scattered light

stardust

1.3 mm1.3 mm

Terrestrial Planet Formation

• SKA 8hrs, 22GHz, 2mas (1500km) =>

S(rms) = 0.02uJy, TB(rms) = 11K

• flux density emitted by a disk element dA

TB ~ 50 to 300 K on AU scales

• less than an Earth mass in sub-AU beam at 140 pc distance of nearby dark clouds

SKA Sensitivity: thermal science at mas resolution

QuickTime™ and aYUV420 codec decompressor

are needed to see this picture.

Embedded Protoplanets

• protoplanet interacts tidally with disk– transfers angular mom.– opens gap– viscosity opposes

• orbital timescales in habitable zone are short (t ~ 1 yr)

• synoptic studies track proper motions of mass concentrations

P. Armitage

Bate et al.

1AU Gap ~ 100 K

Grain Growth and Settling• detailed frequency dependence of dust emissivity

is diagnostic of particle properties, esp. size• SKA sensitive to cm sizes, predicted to settle to

disk mid-plane and seed planetesimals -- sticky question?

TW Hya3.5 cm dust

Wilner et al.

NASA/JPL R. Hurt

QuickTime™ and aYUV420 codec decompressor

are needed to see this picture.

Cosmology -- Water maser disks (Greenhill)

• Hubble constant through direct measurement of distances to galaxies in the Hubble flow.

• Distance to NGC 4258 = 7.4 Mpc +/- 4%

-- maser acceleration and proper motion

-- problem: NGC 4258 is too close => Cepheid calibrator

• Earth baselines => resolution > 0.4 mas => max. distance ~ 120 Mpc

• Currently ~ 30 NGC4258-like masers known

• SKA: ~ 100x more sources, with adequate sensitivity to image => easily 1% measure of Ho

Why do we need to know Ho to 1% ?

Future 1% measures of cosmological parameters via CMB studies require 1% measure of Ho for fully constrained cosmology: covariance!

Current Ho constraint

10% 4%

0.09

0.13

(w)

Ho accur.

Spergel et al. 2006

w ~ 1 +/-

GR tests: Galactic Center Pulsars (Cordes)

•Sgr A* = 3106 black hole with a surrounding star cluster with ~ 108 stars. Many of these are neutron stars.

•Detecting pulsars near Sgr A* is difficult because of the intense scattering screen in front of Sgr A*: d ~ 2000 ν-4 sec (but S ^-3)

•Solution: high sensitivity at high frequency: > 10GHz => width < 0.2sec

Key science:

• Highest probability of finding binary BH-pulsar: strong field GR tests and BH spin.

• Possibly 1000 pulsars orbiting Sgr A* with orbital periods < 100 yr

• Detailed studies of GC ISM -- DM…

Summary and Ruminations

KSP 10% Big step? Up to 45GHz? >1000km?

First light: mol. lines Y Y N

Terrestrial planet formation: PP disks

Y Y Y

Gal. Center Pulsars Y N N

Cosmology: water masers and Ho

Y N Y

• SKA-High is not being pursued by international partners.

• SKA-High is most consistent with current work in USA (EVLA, ATA, DSN).

Rayleigh-Jeans curve implies thermal objects are a factor four stronger (in Jy) at 45GHz relative to 22GHz => a 10% demonstrator becomes 40% of the SKA-22,

Or EVLA at 45GHz ~ 8% SKA-22GHz demonstrator

10% demonstrator

Case for frequencies up to 45 GHz: Thermal objects

0.1 x Arp220

25-50GHz

What we lose without 3 -- 10 GHz

• mas resolution -- Astrometry! Jets, AGN, XRBs

• GRBs, RSNe

• Methanol masers: massive star formation

• Large RM sources

• ms Pulsars with moderate DM

….

END