1. New Worlds, New Horzions, New Science – 09 Mar 2011 1 S. T. Myers Cosmological Galaxy Surveys: The Molecular Perspective Steven T. Myers (NRAO) *National Radio Astronomy Observatory, Socorro, NM Atomic &

2. New Worlds, New Horzions, New Science – 09 Mar 2011 2 S. T. Myers Science Goal: Cosmology Cosmological Galaxy Survey –id and count galaxies (traditional survey) Spectra for 10 4 - 10 9 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

3. New Worlds, New Horzions, New Science – 09 Mar 2011 3 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 115.27 GHz, z=1.5 at 46.11 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)

4. New Worlds, New Horzions, New Science – 09 Mar 2011 4 S. T. Myers Past-gen O/IR Surveys Four published results 1. Eisenstein et al 2005 3D map from SDSS 46,000 galaxies in 0.72 (h -1 Gpc) 3 2. Cole et al 2005 3D 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)

5. New Worlds, New Horzions, New Science – 09 Mar 2011 5 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

6. New Worlds, New Horzions, New Science – 09 Mar 2011 6 S. T. Myers State of the Art: ALFALFA Local Cone The Arecibo ALFALFA survey will see 2000-3000 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

7. New Worlds, New Horzions, New Science – 09 Mar 2011 7 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

8. New Worlds, New Horzions, New Science – 09 Mar 2011 8 S. T. Myers Ultimate Cosmology: Billion Galaxies SKA Survey of HI galaxy emission to z > 1

9. New Worlds, New Horzions, New Science – 09 Mar 2011 9 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

10. New Worlds, New Horzions, New Science – 09 Mar 2011 10 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:0807.3140 (astro-ph)

11. New Worlds, New Horzions, New Science – 09 Mar 2011 11 S. T. Myers The z>1 HI Challenge! HI mass function –z=2 HIMF steep above 10 10 M sun need to characterize HIMF target for science precursors –if M lim x2 then N x 10 -3 to 10 -4 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?

12. New Worlds, New Horzions, New Science – 09 Mar 2011 12 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 2020+ –HI: the Square Kilometer Array (SKA) –CO: the North America Array (NAA)