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High Redshift Galaxies/Galaxy Surveys

High Redshift Galaxies/Galaxy Surveys. ALMA Community Day April 18, 2011 Neal A. Miller University of Maryland. Overview. ALMA as IFU Imaging (continuum) and spectroscopy (line) rolled into one Up to 8GHz bandwidth per polarization, small channels

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High Redshift Galaxies/Galaxy Surveys

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  1. High Redshift Galaxies/Galaxy Surveys ALMA Community Day April 18, 2011 Neal A. Miller University of Maryland

  2. Overview • ALMA as IFU • Imaging (continuum) and spectroscopy (line) rolled into one • Up to 8GHz bandwidth per polarization, small channels • Talk arranged continuum then line • General Topics • SFH of universe • General birth/building of galaxies • Galaxies in the epoch of reionization • Co-evolution of bulges and black holes ALMA Community Day, STScI

  3. Linear Resolution Rough rules of thumb Compact Array: ~5 to 35 kpc resolution Most sources unresolved spatially Extended Array: ~50 pc to 350 pc Angular resolutions a few times better than HST ALMA Community Day, STScI

  4. Continuum: Negative K Correction ALMA Community Day, STScI

  5. Negative K Correction in Play cLanzetta ALMA Community Day, STScI

  6. Continuum: Early Science Possibilities Mosaic observations of significant fields? Tradeoffs: • Intrinsic flux of sources greater at higher frequencies • Field of view is smaller at higher frequencies (about 1’ at Band 3, under 10” at Band 9) • Receiver temperatures higher at higher frequencies ALMA Community Day, STScI

  7. ALMA: Imaging the HUDF Band 3: 100 GHz ~23 pointings to mosaic full 2.2’ square of HUDF Arp 220 sources about 3 μJy flux density 4.7 μJy per pointing, a 3σ detection requires 1.6 μJy rms Over 12 days per pointing! Not enough time in Early Science Full Array: still over a day per pointing ALMA Community Day, STScI

  8. ALMA: Imaging the HUDF Band 6: 240 GHz ~115 pointings to mosaic Full 2.2’ square of HUDF (too many for Early Science) Arp 220 sources about 30 μJy flux density 47 μJy per pointing, a 3σ Detection requires 16 μJyrms 6.9 hr per pointing in Early Science (not enough time in Early Science) Full Array: ~100 hours Total with overheads ALMA Community Day, STScI

  9. Continuum Science • Contiguous area survey observations of deep fields not well suited for Early Science, good for Full Array • Surveys to follow-up individual sources are more appealing • SCUBA, AzTEC, LABOCA, etc. • SMGs, QSOs, HzRGwith flux densities of a few mJy • Band 6 or 7 (800μm to 1.4mm) • Band 7 to reach 0.2 mJy just 9 minutes Early Science • Resolutions of ~1” to ~0.01” (10 kpc to 100 pc) ALMA Community Day, STScI

  10. Individual Source Continuum Surveys • Better positions • Single dish observations with bolometer arrays, tens of arcseconds resolution • Prior follow-up was radio, expensive time requirement • FIR luminosities through SED fitting • Pair with non-RJ data (Spitzer, Herschel) • SFR in absence of AGN • Dust temperatures, masses • Other sources – GRBs? ALMA Community Day, STScI

  11. Spectral Line: CO CO(J=1-0) traces total molecular gas mass Higher J for warmer, denser gas Ratios give excitation properties of molecular gas Line widths for estimate of dynamical mass CO correlates with FIR, hence rough SFR Also for SF efficiency: FIR for current SF, CO for gas reservoir ALMA Community Day, STScI

  12. CO Rotational Ladders Figure from Weiss et al (2007) Sources: Central regions of local starbursts (NGC253, M82) SMGs (SMM16359, highly lensed) QSOs (BR1202, SDSS J1148 at z=6.4) BAL QSO (APM0827) Strength: Peak flux densities of several mJy, integrated lines of a few Jy km/s Widths of a few hundred km/s ALMA Community Day, STScI

  13. Spectral Line: Additional Lines HCN only from dense gas, stronger indicator of star formation HCN line luminosities much higher in SMGs and related objects than in normal spirals [CII] strongest atomic line, cooling line for atomic gas Also [CI]; similar critical density for excitation as CO ALMA Community Day, STScI

  14. Spectral Line Possibilities • Redshift search for SMGs • Difficult to get optical (position, dust obscuration) • Look for CO lines, get 8 GHz per polarization to cover full bands in multiple observations • Line spacing as 1/(1+z) • Absorption lines • CO in host of object types • High z quasars • Lensed “normal” galaxies • LAEs, LBGs? ALMA Community Day, STScI

  15. Possible Questions • Black hole mass from HST, dynamical mass from CO? • SF efficiency? Pair FIR with line luminosity • Morphology – big disks or mergers for SMGs? • Formation of present day massive ellipticals? • AGN unification and evolutionary models? • Starburst to obscured AGN to unobscured AGN? ALMA Community Day, STScI

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