New Worlds, New Horzions, New Science – 09 Mar S. T. Myers Cosmological Galaxy Surveys: The Molecular Perspective Steven T. Myers (NRAO) *National Radio Astronomy Observatory, Socorro, NM Atomic &

New Worlds, New Horzions, New Science – 09 Mar S. T. Myers Science Goal: Cosmology Cosmological Galaxy Survey –id and count galaxies (traditional survey) Spectra for galaxies to z > 1.5 in > Gpc volume –cosmological parameters “Dark Energy” via H(z) measurements (BAO &c) –growth of structure (counts, galaxy evolution) –alternative: “intensity mapping” (angular power spectrum) Galaxy Continuum Photometry –synchrotron / free-free in Milky Way-like galaxies –weak lensing studies (DE) –AGN surveys

New Worlds, New Horzions, New Science – 09 Mar S. T. Myers The Probes: Key Radio Lines 1 - Atomic Hydrogen –HI line (rest 1.42 GHz, z=1.5 at 568 MHz) –single line in “clean” part of spectrum single line redshift determination almost assured 2 - Molecular CO –CO ladder (1-0 rest GHz, z=1.5 at GHz) –whole J ladder of lines (115,230,346,461…) ambiguity in redshift –forested area of spectrum many weaker lines could contribute to correlated signal Other (will not discuss in detail)

New Worlds, New Horzions, New Science – 09 Mar S. T. Myers Past-gen O/IR Surveys Four published results 1. Eisenstein et al D map from SDSS 46,000 galaxies in 0.72 (h -1 Gpc) 3 2. Cole et al D map from 2dFGRS at AAO 221,000 galaxies in 0.2 (h -1 Gpc) 3 3. Padmanabhan et al 2007 Set of 2D maps from SDSS 600,000 galaxies in 1.5 (h -1 Gpc) 3 4. Blake et al 2007 (Same data as above) (spectro-z) 5% (spectro-z) 3% (photo-z) 5% Radio surveys are currently lagging in numbers of detections AAO 4-m telescope at Siding Spring, Australia SDSS 2.5-m telescope, Apache Point, NM Thanks to Pat McDonald (CITA)

New Worlds, New Horzions, New Science – 09 Mar S. T. Myers Complementarity: O/IR Spectroscopic Surveys SKA in context: ~1000 million galaxies z<2.5 in 8-60 Gpc 3 comoving! Warren Moos: presentation to BEPAC

New Worlds, New Horzions, New Science – 09 Mar S. T. Myers State of the Art: ALFALFA Local Cone The Arecibo ALFALFA survey will see galaxies with HI mass to 10 7 M sun The SKA-mid pathfinders will improve mapping speeds by 10-25x Optical Galaxies in Coma “cone” current science precursors can push us out to z~0.2 courtesy M. Haynes

New Worlds, New Horzions, New Science – 09 Mar S. T. Myers State of the Art: VLA VIVA survey Virgo cluster –47 galaxies47 galaxies –HI size magnified x10HI size magnified x10 –20 x 20 deg field20 x 20 deg field –A. Chung et al.A. Chung et al. High resolution –ID with O/IRID with O/IR –kinematics of gaskinematics of gas –dynamics of massdynamics of mass

New Worlds, New Horzions, New Science – 09 Mar S. T. Myers Ultimate Cosmology: Billion Galaxies SKA Survey of HI galaxy emission to z > 1

New Worlds, New Horzions, New Science – 09 Mar S. T. Myers SKA for Dark Energy SKA as w-machine –10 9 galaxy BAO survey –also weak lensing (continuum) –target 0.01 in w Design Driver –target precision requires survey speed of 4-6 x 10 9 m 4 K -2 deg 2 –this is a SK area with 10 deg 2 FOV –would also like to identify individual galaxies (need arcsecond resolution) –survey database for other science Options –might be able to do BAO power spectrum with ultra-compact Hydrogen array/telescope –but will not be of general use… Rawlings et al. SKA Science Book AR Model C Rawlings et al. SKA Science Book

New Worlds, New Horzions, New Science – 09 Mar S. T. Myers SKA for Dark Energy SKA as w-machine –10 9 galaxy BAO survey –also weak lensing (continuum) –target 0.01 in w Design Driver –target precision requires survey speed of 4-6 x 10 9 m 4 K -2 deg 2 –this is a SK area with 10 deg 2 FOV –would also like to identify individual galaxies (need arcsecond resolution) –survey database for other science Options –might be able to do BAO power spectrum with ultra-compact Hydrogen array/telescope –but will not be of general use… Rawlings et al. SKA Science Book SKA BAO Tang et al. arXiv: (astro-ph)

New Worlds, New Horzions, New Science – 09 Mar S. T. Myers The z>1 HI Challenge! HI mass function –z=2 HIMF steep above M sun need to characterize HIMF target for science precursors –if M lim x2 then N x to or worse! in danger of getting 1 –precision Dark Energy requires high survey speed need SSFoM > 4-6 x 10 9 m 4 K -2 deg 2 is this important enough? –upgrade path and technology development key to ultimate HI cosmology goals Rawlings et al. SKA Science Book AR Model C z=1 z=2 How do we get to precision “DE” sensitivity?

New Worlds, New Horzions, New Science – 09 Mar S. T. Myers Instrumenting the Science Current-gen facilities –Expanded Very Large Array EVLA (NM) –Allen Telescope Array ATA (CA) –Arecibo Observatory AO (PR) –Green Bank Telescope GBT (WV) Next-gen SKA Precursors –ASKAP (Australia) –MeerKAT (S.Africa) Ultimate Science –HI: the Square Kilometer Array (SKA) –CO: the North America Array (NAA)