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 H o 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 coverage Epoch 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. ALMA z~10 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 M o = fuel for star formation. Currently: 2 solid detections, 2 likely at z~6 FWHM=350 km/s z=6.42 Radio-FIR correlation 50K  M dust ~ 1e8 M o  Dust heating: star formation or AGN?  Follows Radio-FIR correlation: SFR ~ 3000 M o /yr VLA PdBI

J : VLA imaging of CO3-2  Separation = 0.3” = 1.7 kpc  T B = 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 M BH - M bulge relation at high z -- only direct probe of host galaxies M dyn ~ 2e10/(sin  )^2 M o M gas ~ 2e10 M o M bulge ~1e12 M o (predicted) z=6.42 z<0.5 M BH = M bulge

[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 M o /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 n cr > 1e7cm^-3 for higher orders => higher order not (generally) excited? Dense gas tracers best studied with cm telescopes HCN uJy 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 t univ < 1Gyr  Multi-scale simulation isolating most massive halo in 3 Gpc^3 (co-mov)  Stellar mass ~ 1e12 M o forms in series (7) of major, gas rich mergers from z~14, with SFR ~ 1e3 - 1e4 M o /yr  SMBH of ~ 2e9 M o forms via Eddington-limited accretion + mergers  Evolves into giant elliptical galaxy in massive cluster (3e15 M o ) by z= 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. 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 star dust 1.3 mm Terrestrial Planet Formation

SKA 8hrs, 22GHz, 2mas (1500km) => S(rms) = 0.02uJy, T B (rms) = 11K flux density emitted by a disk element dA T B ~ 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

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 Hya 3.5 cm dust Wilner et al. NASA/JPL R. Hurt

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 H o

Why do we need to know H o to 1% ? Future 1% measures of cosmological parameters via CMB studies require 1% measure of H o for fully constrained cosmology: covariance! Current Ho constraint 10%4%  (w) H o accur. Spergel et al w ~ 1 +/- 

GR tests: Galactic Center Pulsars (Cordes) Sgr A* = 3  10 6 black hole with a surrounding star cluster with ~ 10 8 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 KSP10% Big step?Up to 45GHz?>1000km? First light: mol. linesYYN Terrestrial planet formation: PP disks YYY Gal. Center PulsarsYNN Cosmology: water masers and H o YNY 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 Arp GHz

What we lose without GHz mas resolution -- Astrometry! Jets, AGN, XRBs GRBs, RSNe Methanol masers: massive star formation Large RM sources ms Pulsars with moderate DM ….

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