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HI in Galaxies at Redshifts 0.1 to 1.0: Current and Future Observations Using Optical Redshifts for HI Coadding Deep Surveys of the Radio Universe with SKA Pathfinders Philip Lah
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Collaborators: Frank Briggs (ANU) Jayaram Chengalur (NCRA) Matthew Colless (AAO) Roberto De Propris (CTIO) Michael Pracy (ANU)
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Talk Outline Current Observations HI in star forming galaxies at z = 0.24 HI in Abell 370, a galaxy cluster at z = 0.37 Future Observations using ASKAP and WiggleZ using MeerKAT and zCOSMOS
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Current Observations - HI coadding
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Giant Metrewave Radio Telescope
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Anglo-Australian Telescope
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multi-object, fibre fed spectrograph 2dF/AAOmega instrument
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The Fujita galaxies H emission galaxies at z = 0.24
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The Fujita Galaxies Subaru Field 24’ × 30’ narrow band imaging Hα emission at z = 0.24 (Fujita et al. 2003, ApJL, 586, L115) 348 Fujita galaxies 121 redshifts using AAT GMRT ~48 hours on field DEC RA
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Coadded HI Spectrum
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HI spectrum all Fujita galaxies neutral hydrogen gas measurement using 121 redshifts - weighted average M HI = (2.26 ± 0.90) ×10 9 M raw binned
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The Cosmic Hydrogen Gas Density
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my new point The Cosmic Gas Density vs. Redshift
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my new point Cosmic Neutral Gas Density vs. Time
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Abell 370 a galaxy cluster at z = 0.37
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Abell 370 large galaxy cluster at z = 0.37, of order same size of Coma similar cluster velocity dispersion and X-ray gas temperature optical imaging ANU 40 inch telescope spectroscopic follow-up with the AAT GMRT ~34 hours on cluster
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Abell 370 galaxy cluster 324 galaxies with redshifts z = 0.345 to 0.387 105 blue galaxies 219 red galaxies Abell 370 galaxy cluster
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3σ extent of X-ray gas R 200 radius at which cluster 200 times denser than the general field
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The Measuring the HI signal
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Galaxy Sizes For HI stacking I want the galaxies to be unresolved. For the Fujita galaxies I used an estimate of the HI size from the optical properties using information on nearby spiral and irregular field galaxies. Complication! The Abell 370 galaxies are a mixture of early and late types in a variety of environments. Solution I made multiple measurements of the galaxies HI mass using different smoothing sizes.
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Galaxy Sizes For HI stacking I want the galaxies to be unresolved. For the Fujita galaxies I used an estimate of the HI size from the optical properties using information on nearby spiral and irregular field galaxies. Complication! The Abell 370 galaxies are a mixture of early and late types in a variety of environments. Solution I made multiple measurements of the galaxies HI mass using different smoothing sizes.
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Galaxy Sizes For HI stacking I want the galaxies to be unresolved. For the Fujita galaxies I used an estimate of the HI size from the optical properties using information on nearby spiral and irregular field galaxies. Complication! The Abell 370 galaxies are a mixture of early and late types in a variety of environments. Solution I made multiple measurements of the galaxies HI mass using different smoothing sizes.
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The Average HI Mass Measurements
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HI mass 324 galaxies 219 galaxies 105 galaxies 94 galaxies 168 galaxies 156 galaxies 104 galaxies 220 galaxies
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HI mass 324 galaxies 219 galaxies 105 galaxies 94 galaxies 168 galaxies 156 galaxies 104 galaxies 220 galaxies
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HI mass 324 galaxies 219 galaxies 105 galaxies 94 galaxies 168 galaxies 156 galaxies 104 galaxies 220 galaxies
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HI mass 324 galaxies 219 galaxies 105 galaxies 94 galaxies 168 galaxies 156 galaxies 104 galaxies 220 galaxies
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HI mass 324 galaxies 219 galaxies 105 galaxies 94 galaxies 168 galaxies 156 galaxies 104 galaxies 220 galaxies
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HI spectra – Large Smoothing M HI = (6.6 ± 3.5) ×10 9 M M HI = (23.0 ± 7.7) ×10 9 M
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HI Flux – All Galaxies 30 arcsec across ~150 kpc across
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HI Flux – The Blue Galaxies Outside X-ray Gas 30 arcsec across ~150 kpc across
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Future Observations - HI coadding
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What I could do with the SKA pathfinders if you gave them to me TODAY.
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ASKAP and MeerKAT parameters ASKAPMeerKAT Number of Dishes 4580 Dish Diameter 12 m Aperture Efficiency 0.8 System Temp. 35 K30 K Frequency range 700 – 1800 MHz700 – 10000 MHz Instantaneous bandwidth 300 MHz512 MHz Field of View: at 1420 MHz (z = 0) at 700 MHz (z = 1) 30 deg 2 1.2 deg 2 4.8 deg 2 Maximum Baseline Length 8 km10 km
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ASKAP and MeerKAT parameters ASKAPMeerKAT Number of Dishes 4580 Dish Diameter 12 m Aperture Efficiency 0.8 System Temp. 35 K30 K Frequency range 700 – 1800 MHz700 – 10000 MHz Instantaneous bandwidth 300 MHz512 MHz Field of View: at 1420 MHz (z = 0) at 700 MHz (z = 1) 30 deg 2 1.2 deg 2 4.8 deg 2 Maximum Baseline Length 8 km10 km
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ASKAP and MeerKAT parameters ASKAPMeerKAT Number of Dishes 4580 Dish Diameter 12 m Aperture Efficiency 0.8 System Temp. 35 K30 K Frequency range 700 – 1800 MHz700 – 10000 MHz Instantaneous bandwidth 300 MHz512 MHz Field of View: at 1420 MHz (z = 0) at 700 MHz (z = 1) 30 deg 2 1.2 deg 2 4.8 deg 2 Maximum Baseline Length 8 km10 km z = 0.4 to 1.0 in a single observation z = 0.2 to 1.0 in a single observation
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WiggleZ and zCOSMOS WiggleZzCOSMOS Instrument/TelescopeAAOmega on the AATVIMOS on the VLT Target Selection ultraviolet using the GALEX satellite optical I band I AB < 22.5 Survey Area 1000 deg 2 total 7 fields minimum size of ~100 deg 2 COSMOS field single field ~2 deg 2 Primary Redshift Range 0.5 < z < 1.00.1 < z < 1.2 Survey Timeline2006 to 20102005 to 2008 n z by survey end176,00020,000 n z in March 2008~62,000~10,000
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WiggleZ and zCOSMOS WiggleZzCOSMOS Instrument/TelescopeAAOmega on the AATVIMOS on the VLT Target Selection ultraviolet using the GALEX satellite optical I band I AB < 22.5 Survey Area 1000 deg 2 total 7 fields minimum size of ~100 deg 2 COSMOS field single field ~2 deg 2 Primary Redshift Range 0.5 < z < 1.00.1 < z < 1.2 Survey Timeline2006 to 20102005 to 2008 n z by survey end176,00020,000 n z in March 2008~62,000~10,000
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WiggleZ and zCOSMOS WiggleZzCOSMOS Instrument/TelescopeAAOmega on the AATVIMOS on the VLT Target Selection ultraviolet using the GALEX satellite optical I band I AB < 22.5 Survey Area 1000 deg 2 total 7 fields minimum size of ~100 deg 2 COSMOS field single field ~2 deg 2 Primary Redshift Range 0.5 < z < 1.00.1 < z < 1.2 Survey Timeline2006 to 20102005 to 2008 n z by survey end176,00020,000 n z in March 2008~62,000~10,000
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WiggleZ and zCOSMOS WiggleZzCOSMOS Instrument/TelescopeAAOmega on the AATVIMOS on the VLT Target Selection ultraviolet using the GALEX satellite optical I band I AB < 22.5 Survey Area 1000 deg 2 total 7 fields minimum size of ~100 deg 2 COSMOS field single field ~2 deg 2 Primary Redshift Range 0.5 < z < 1.00.1 < z < 1.2 Survey Timeline2006 to 20102005 to 2008 n z by survey end176,00020,000 n z in March 2008~62,000~10,000
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WiggleZ and zCOSMOS WiggleZzCOSMOS Instrument/TelescopeAAOmega on the AATVIMOS on the VLT Target Selection ultraviolet using the GALEX satellite optical I band I AB < 22.5 Survey Area 1000 deg 2 total 7 fields minimum size of ~100 deg 2 COSMOS field single field ~2 deg 2 Primary Redshift Range 0.5 < z < 1.00.1 < z < 1.2 Survey Timeline2006 to 20102005 to 2008 n z by survey end176,00020,000 n z in March 2008~62,000~10,000
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WiggleZ and zCOSMOS WiggleZzCOSMOS Instrument/TelescopeAAOmega on the AATVIMOS on the VLT Target Selection ultraviolet using the GALEX satellite optical I band I AB < 22.5 Survey Area 1000 deg 2 total 7 fields minimum size of ~100 deg 2 COSMOS field single field ~2 deg 2 Primary Redshift Range 0.5 < z < 1.00.1 < z < 1.2 Survey Timeline2006 to 20102005 to 2008 n z by survey end176,00020,000 n z in March 2008~62,000~10,000
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WiggleZ and zCOSMOS WiggleZzCOSMOS Instrument/TelescopeAAOmega on the AATVIMOS on the VLT Target Selection ultraviolet using the GALEX satellite optical I band I AB < 22.5 Survey Area 1000 deg 2 total 7 fields minimum size of ~100 deg 2 COSMOS field single field ~2 deg 2 Primary Redshift Range 0.5 < z < 1.00.1 < z < 1.2 Survey Timeline2006 to 20102005 to 2008 n z by survey end176,00020,000 n z in March 2008~62,000~10,000
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WiggleZ and ASKAP
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WiggleZ field data as of March 2008 z = 0.1 to 1.0 ASKAP beam size Diameter 6.2 degrees Area 30 deg 2 ~10 degrees across
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ASKAP & WiggleZ 100hrs n z = 5975
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ASKAP & WiggleZ 100hrs n z = 5975
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ASKAP & WiggleZ 100hrs n z = 5975
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ASKAP & WiggleZ 1000hrs n z = 5975
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zCOSMOS and MeerKAT
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zCOSMOS field data as of March 2008 z = 0.1 to 1.0 MeerKAT beam size at 1420 MHz z = 0 MeerKAT beam size at 1000 MHz z = 0.4 ~1.3 degrees across
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MeerKAT & zCOSMOS 100hrs n z = 7615
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MeerKAT & zCOSMOS 100hrs n z = 7615
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MeerKAT & zCOSMOS 100hrs n z = 7615
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MeerKAT & zCOSMOS 1000hrs n z = 7615
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Conclusion
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can use coadding with optical redshifts to make measurement of the HI 21 cm emission from galaxies at redshifts z > 0.1 the measured cosmic neutral gas density at z = 0.24 is consistent with that from damped Lyα measurements galaxy cluster Abell 370 at z = 0.37 has significantly amounts of neutral hydrogen gas the SKA pathfinders ASKAP and MeerKAT can measure significant amounts of HI 21 cm emission out to z = 1.0 using the coadding technique with existing optical redshift surveys Conclusion
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