Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Planetary nebula wikipedia , lookup
Leibniz Institute for Astrophysics Potsdam wikipedia , lookup
Outer space wikipedia , lookup
Dark matter wikipedia , lookup
Astrophysical X-ray source wikipedia , lookup
Cosmic distance ladder wikipedia , lookup
Gravitational lens wikipedia , lookup
Weak gravitational lensing wikipedia , lookup
Star formation wikipedia , lookup
H II region wikipedia , lookup
The Evolution of Gas in Galaxies Philip Lah End of Thesis Colloquium Chair of Supervisory Panel: Frank Briggs (ANU) Supervisory Panel: Jayaram Chengalur (NCRA) Matthew Colless (AAO) Roberto De Propris (CTIO) Erwin De Blok (UCT) With Assistance From: Michael Pracy (ANU) Talk Outline Introduction • HI 21-cm emission, galaxies and star formation • the cosmic star formation rate density and the cosmic HI density • high redshift HI 21-cm emssion observations and the coadding technique Current Observations with the HI coadding technique • HI in star-forming galaxies at z = 0.24 • HI in galaxies around Abell 370, a galaxy cluster at z = 0.37 Future Observations with SKA pathfinders • using ASKAP and WiggleZ • using MeerKAT and zCOSMOS • ideas on the evolution of gas in galaxies Talk Outline Introduction • HI 21-cm emission, galaxies and star formation • the cosmic star formation rate density and the cosmic HI density • high redshift HI 21-cm emssion observations and the coadding technique Current Observations with the HI coadding technique • HI in star-forming galaxies at z = 0.24 • HI in galaxies around Abell 370, a galaxy cluster at z = 0.37 Future Observations with SKA pathfinders • using ASKAP and WiggleZ • using MeerKAT and zCOSMOS • ideas on the evolution of gas in galaxies Talk Outline Introduction • HI 21-cm emission, galaxies and star formation • the cosmic star formation rate density and the cosmic HI density • high redshift HI 21-cm emssion observations and the coadding technique Current Observations with the HI coadding technique • HI in star-forming galaxies at z = 0.24 • HI in galaxies around Abell 370, a galaxy cluster at z = 0.37 Future Observations with SKA pathfinders • using ASKAP and WiggleZ • using MeerKAT and zCOSMOS • ideas on the evolution of gas in galaxies HI 21-cm Emission Neutral atomic hydrogen creates 21-cm radiation proton electron Neutral atomic hydrogen creates 21-cm radiation Neutral atomic hydrogen creates 21 cm radiation Neutral atomic hydrogen creates 21-cm radiation Neutral atomic hydrogen creates 21-cm radiation photon Neutral atomic hydrogen creates 21-cm radiation decay half life ~10 million years (31014 s) HI 21-cm Emission From Galaxies Galaxy M33: optical Galaxy M33: HI 21-cm emission Galaxy M33: optical and HI Galaxy M33: optical HI Gas and Star Formation neutral atomic hydrogen gas cloud (HI) molecular gas cloud (H2) star formation Galaxy HI mass vs Star Formation Rate Galaxy HI Mass vs Star Formation Rate HIPASS & IRAS data z~0 Doyle & Drinkwater 2006 The Star Formation Rate Density of the Universe Star Formation Rate Density Evolution Compilation by Hopkins 2004 The HI Gas Density of the Universe HI Gas Density Evolution Not a log scale HI Gas Density Evolution Lah et al. 2007 coadded HI 21cm Prochaska et al. 2005 & 2009 DLAs Zwaan et al. 2005 HIPASS HI 21cm Rao et al. 2006 DLAs from MgII absorption HI 21cm Emission at High Redshift HI 21cm emission at z > 0.1 Zwaan et al. 2001 WSRT 200 hours HI 21cm emission at z > 0.1 Verheijen et al. 2004 VLA 80 hours HI 21cm emission at z > 0.1 Verheijen et al. 2007 WSRT 180 & 240 hours HI 21cm emission at z > 0.1 Catinella et al. 2007 Arecibo 2-6 hours per galaxy HI 21cm emission at z > 0.1 Lah et al. 2007 coadded GMRT 81 hours Lah et al. 2009 coadded GMRT 63 hours Coadding HI signals Coadding HI signals Radio Data Cube DEC RA Coadding HI signals Radio Data Cube DEC positions of optical galaxies RA flux Coadding HI signals frequency Coadding HI signals z1 flux z2 z3 frequency z1, z2 & z3 optical redshifts of galaxies Coadding HI signals z1 flux z2 z3 velocity z1, z2 & z3 optical redshifts of galaxies Coadding HI signals z1 flux z2 Coadded HI signal z3 velocity velocity z1, z2 & z3 optical redshifts of galaxies Current Observations HI coadding Giant Metrewave Radio Telescope Giant Metrewave Radio Telescope Giant Metrewave Radio Telescope Giant Metrewave Radio Telescope Anglo-Australian Telescope 2dF/AAOmega instrument multi-object, fibre fed spectrograph The Fujita galaxies H emission galaxies at z = 0.24 The Fujita Galaxies Subaru Field 24’ × 30’ narrow band imaging Hα emission at z = 0.24 look-back time ~3 billion years (Fujita et al. 2003, ApJL, 586, L115) DEC 348 Fujita galaxies 121 redshifts using AAT GMRT ~48 hours on field RA Star Formation Rate Density Evolution Compilation by Hopkins 2004 Star Formation Rate Density Evolution Fujita et al. 2003 value Compilation by Hopkins 2004 Coadded HI Spectrum Fujita galaxies coadded HI spectrum raw HI spectrum allusing 121 redshifts - weighted average Fujita galaxies coadded HI spectrum raw HI spectrum allusing 121 redshifts - weighted average binned MHI = (2.26 ± 0.90) ×109 M The HI Gas Density of the Universe HI Gas Density Evolution Lah et al. 2007 coadded HI 21cm Galaxy HI mass vs Star Formation Rate Galaxy HI Mass vs Star Formation Rate HIPASS & IRAS data z~0 Doyle & Drinkwater 2006 HI Mass vs Star Formation Rate at z = 0.24 all 121 galaxies line from Doyle & Drinkwater 2006 HI Mass vs Star Formation Rate at z = 0.24 42 bright L(Hα) galaxies 42 medium L(Hα) galaxies line from Doyle & Drinkwater 2006 37 faint L(Hα) galaxies Abell 370 a galaxy cluster at z = 0.37 Galaxy Clusters and HI gas Galaxy Cluster: Coma Nearby Galaxy Clusters Are Deficient in HI Gas HI Deficiency in Clusters DefHI = log(MHI exp. / MHI obs) DefHI = 1 is 10% of expected HI gas expected gas estimate based on optical diameter and Hubble type interactions between galaxies and interactions with the inter-cluster medium removes the gas from the galaxies Gavazzi et al. 2006 Why target moderate redshift clusters for HI gas? Why target moderate redshift clusters? • at moderate redshifts the whole of the galaxy cluster core and its outskirts are within the field of view of a radio telescope (nearby this not the case – one has to target individual galaxies in clusters one by one) • around a cluster there are many more galaxies that lie within a single telescope pointing than for a typical field pointing • the Butcher-Oemler effect Why target moderate redshift clusters? • at moderate redshifts the whole of the galaxy cluster core and its outskirts are within the field of view of a radio telescope (nearby this not the case – one has to target individual galaxies in clusters one by one) • around a cluster there are many more galaxies that lie within a single telescope pointing than for a typical field pointing • the Butcher-Oemler effect Why target moderate redshift clusters? • at moderate redshifts the whole of the galaxy cluster core and its outskirts are within the field of view of a radio telescope (nearby this not the case – one has to target individual galaxies in clusters one by one) • around a cluster there are many more galaxies that lie within a single telescope pointing than for a typical field pointing • the (Harvey) Butcher-Oemler effect Blue Fraction, fB The Butcher-Oemler Effect Redshift, z Blue Fraction, fB The Butcher-Oemler Effect Abell 370 Redshift, z Abell 370 a galaxy cluster at z = 0.37 Abell 370, a galaxy cluster at z = 0.37 large galaxy cluster of order same size as Coma similar cluster velocity dispersion and X-ray gas temperature optical imaging ANU 40 inch telescope spectroscopic follow-up with the AAT Abell 370 cluster core, ESO VLT image GMRT ~34 hours on cluster HI z = 0.35 to 0.39 look-back time ~4 billion years Abell 370 galaxy Abell 370 galaxy cluster cluster 324 galaxies 105 blue (B-V 0.57) 219 red (B-V > 0.57) Abell 370 galaxy Abell 370 galaxy cluster cluster 3σ extent of X-ray gas R200 radius at which cluster 200 times denser than the general field Coadded HI Mass Measurements HI mass 324 galaxies 219 galaxies 105 galaxies Inner Regions Outer Regions 94 galaxies 156 galaxies The galaxies around Abell 370 are 168a galaxies mixture of early and late types in a variety of environments. 110 galaxies 214 galaxies HI mass 324 galaxies 219 galaxies 105 galaxies 94 galaxies 156 galaxies 168 galaxies 110 galaxies 214 galaxies HI mass 324 galaxies 219 galaxies 105 galaxies 94 galaxies 156 galaxies HI deficient 11 blue galaxies within X-ray gas 168 galaxies 110 galaxies 214 galaxies HI mass 324 galaxies 219 galaxies 105 galaxies 94 galaxies 156 galaxies 168 galaxies 110 galaxies 214 galaxies HI mass 324 galaxies 219 galaxies 105 galaxies 94 galaxies 156 galaxies 168 galaxies 110 galaxies 214 galaxies HI Density Comparisons HI density Whole Redshift Region z = 0.35 to 0.39 Outer Cluster Region Inner Cluster Region Distribution of galaxies around Abell 370 cluster redshift HI density Whole Redshift Region z = 0.35 to 0.39 Outer Cluster Region Inner Cluster Region Distribution of galaxies around Abell 370 cluster redshift within R200 region HI density Whole Redshift Region z = 0.35 to 0.39 Outer Cluster Region Inner Cluster Region Galaxy HI mass vs Star Formation Rate Galaxy HI Mass vs Star Formation Rate HIPASS & IRAS data z~0 Doyle & Drinkwater 2006 HI Mass vs Star Formation Rate in Abell 370 all 168 [OII] emission galaxies Average line from Doyle & Drinkwater 2006 HI Mass vs Star Formation Rate in Abell 370 81 blue [OII] emission galaxies Average 87 red [OII] emission galaxies line from Doyle & Drinkwater 2006 Future Observations HI coadding with SKA Pathfinders SKA – Square Kilometer Array • SKA promises both high sensitivity with a wide field of view • possible SKA sites – South Africa and Australia • both South Africa and Australia are currently building SKA pathfinder telescopes to strengthen their case for site selection • the SKA pathfinder telescopes will also do interesting science SKA – Square Kilometer Array • SKA promises both high sensitivity with a wide field of view • possible SKA sites – South Africa and Australia (RFI quiet areas) • both South Africa and Australia are currently building SKA pathfinder telescopes to strengthen their case for site selection • the SKA pathfinder telescopes will also do interesting science SKA – Square Kilometer Array • SKA promises both high sensitivity with a wide field of view • possible SKA sites – South Africa and Australia (RFI quiet areas) • both South Africa and Australia are currently building SKA pathfinder telescopes to strengthen their case for site selection • the SKA pathfinder telescopes will also do interesting science The SKA pathfinders ASKAP MeerKAT South African SKA pathfinder ASKAP and MeerKAT ASKAP parameters MeerKAT 30 (36) 80 12 m 12 m 0.8 0.8 50 K 30 K 700 – 1800 MHz 500 – 2500 MHz 300 MHz 512 MHz Field of View: at 1420 MHz (z = 0) at 700 MHz (z = 1) 30 deg2 30 deg2 1.2 deg2 4.8 deg2 Maximum Baseline Length 2 (6) km 10 km Number of Dishes Dish Diameter Aperture Efficiency System Temp. Frequency range Instantaneous bandwidth ASKAP and MeerKAT ASKAP parameters MeerKAT 30 (36) 80 12 m 12 m 0.8 0.8 35 K 30 K 700 – 1800 MHz 500 – 2500 MHz 300 MHz 512 MHz Field of View: at 1420 MHz (z = 0) at 700 MHz (z = 1) 30 deg2 30 deg2 1.2 deg2 4.8 deg2 Maximum Baseline Length 2 (8) km 10 km Number of Dishes Dish Diameter Aperture Efficiency System Temp. Frequency range Instantaneous bandwidth ASKAP and MeerKAT ASKAP parameters MeerKAT Number of Dishes Dish Diameter Aperture Efficiency System Temp. Frequency range Instantaneous bandwidth Field of View: at 1420 MHz (z = 0) at 700 MHz (z = 1) Maximum Baseline Length 30 (36) 80 12 m 12 m 0.8 0.8 35 K 30 K 700 – 1800 MHz 500 – 2500 MHz 300 MHz 512 MHz z = 0.4 to 1.0 in a z = 0.2 to 1.0 in a single30 observation single1.2 observation deg2 deg2 30 deg2 4.8 deg2 2 (8) km 10 km Simulated ASKAP HI detections (Johnston et al. 2007) z = 0.45 to 1.0 one year observations (8760 hours) single telescope pointing, assumes no evolution in the HI mass function Light grey 30 dishes Tsys = 50 K Dark grey 45 dishes Tsys = 35 K MeerKAT ~4 times more sensitive but smaller field of view Coadding HI with the SKA Pathfinders Optical Redshift Surveys WiggleZ and zCOSMOS WiggleZ zCOSMOS Instrument/Telescope AAOmega on the AAT VIMOS on the VLT Target Selection ultraviolet using the GALEX satellite optical I band IAB < 22.5 Survey Area 1000 deg2 total 7 fields minimum size of ~100 deg2 COSMOS field single field ~2 deg2 Primary Redshift Range 0.5 < z < 1.0 0.1 < z < 1.2 Survey Timeline 2006 to 2010 2005 to 2008 nz by survey end 200,000 20,000 WiggleZ and zCOSMOS WiggleZ zCOSMOS Instrument/Telescope AAOmega on the AAT VIMOS on the VLT Target Selection ultraviolet using the GALEX satellite optical I band IAB < 22.5 Survey Area 1000 deg2 total 7 fields minimum size of ~100 deg2 COSMOS field single field ~2 deg2 Primary Redshift Range 0.5 < z < 1.0 0.1 < z < 1.2 Survey Timeline 2006 to 2010 2005 to 2008 nz by survey end 200,000 20,000 WiggleZ and zCOSMOS WiggleZ zCOSMOS Instrument/Telescope AAOmega on the AAT VIMOS on the VLT Target Selection ultraviolet using the GALEX satellite optical I band IAB < 22.5 Survey Area 1000 deg2 total 7 fields minimum size of ~100 deg2 COSMOS field single field ~2 deg2 Primary Redshift Range 0.5 < z < 1.0 0.1 < z < 1.2 Survey Timeline 2006 to 2010 2005 to 2008 nz by survey end 200,000 20,000 WiggleZ and ASKAP WiggleZ field square ~10 degrees across data as of May 2009 z = 0.45 to 1.0 ASKAP Field of View Area 30 deg2 ASKAP & WiggleZ 100hrs nz = 7009 ASKAP & WiggleZ 100hrs nz = 7009 ASKAP & WiggleZ 100hrs nz = 7009 ASKAP & WiggleZ 1000hrs Can break up observations among multiple WiggleZ fields nz = 7009 zCOSMOS and MeerKAT zCOSMOS field MeerKAT beam size at 1420 MHz z = 0 MeerKAT beam size at 1000 MHz z = 0.4 square ~1.3 degrees across data as of March 2008 z = 0.2 to 1.0 7118 galaxies MeerKAT & zCOSMOS 100hrs ~65 per cent of zCOSMOS galaies are star-forming, blue, diskdominate galaxies (Mignoli et al. 2008) nz = 4627 MeerKAT & zCOSMOS 100hrs nz = 4627 MeerKAT & zCOSMOS 100hrs nz = 4627 MeerKAT & zCOSMOS 1000hrs nz = 4627 HI Science with SKA Pathfinders at High Redshift Why is there a dramatic evolution in the Cosmic Star Formation Rate Density and only minimal evolution in the Cosmic HI Gas Density? SFRD & HI density Evolution Star Formation Rate Density Evolution HI Density Evolution Evolution of HI Gas in Galaxies log(SFR) log(MHI) SFR = a (MHI)m HI = MHI SFRD = SFR Vol Vol SFRD = a × (MHI)m Vol m ~ 1.7 at z = 0 (Doyle & Drinkwater 2006) Evolution of HI Gas in Galaxies log(SFR) log(MHI) SFR = a (MHI)m HI = MHI SFRD = SFR Vol Vol SFRD = a × (MHI)m Vol m ~ 1.7 at z = 0 (Doyle & Drinkwater 2006) Evolution of HI Gas in Galaxies log(SFR) log(MHI) SFR = a (MHI)m HI = MHI SFRD = SFR Vol Vol SFRD = a × (MHI)m Vol m ~ 1.7 at z = 0 (Doyle & Drinkwater 2006) Evolution of HI Gas in Galaxies log(SFR) log(MHI) SFR = a (MHI)m HI = MHI SFRD = SFR Vol Vol SFRD = a × (MHI)m Vol m ~ 1.7 at z = 0 (Doyle & Drinkwater 2006) Evolution of HI Gas in Galaxies log(SFR) log(MHI) SFR = a (MHI)m HI = MHI SFRD = SFR Vol Vol SFRD = a × (MHI)m Vol m ~ 1.7 at z = 0 (Doyle & Drinkwater 2006) Testing Ideas on HI Gas Evolution Generated HI Mass Functions Integrated HI density = current value (~5×107 M Mpc-3) Integrated SFRD = maximum value observed (~0.3 M yr-1 Mpc-3) Generated HI Mass Functions Integrated HI density = twice current value (~108 M Mpc-3) Integrated SFRD = maximum value observed (~0.3 M yr-1 Mpc-3) Varying Galaxy SFR-HI Gas Relationship SFR = a (MHI)m Integrated HI density = current value (~5×107 M Mpc-3) Integrated SFRD = maximum value observed (~0.3 M yr-1 Mpc-3) current values Observational Evidence Downsizing • the bulk of the stellar populations of the most massive galaxies formed at early times (Heavens et al. 2004, Thomas et al. 2005 & others) • the sites of active star formation shift from the high-mass galaxies at earliest times to the lower-mass galaxies at later periods (Cowie et al. 1996, Gunzman et al. 1997 & others) • high mass galaxies with active star formation highest HI gas content? • SKA pathfinders observations test hypotheses Downsizing • the bulk of the stellar populations of the most massive galaxies formed at early times (Heavens et al. 2004, Thomas et al. 2005 & others) • the sites of active star formation shift from the high-mass galaxies at earliest times to the lower-mass galaxies at later periods (Cowie et al. 1996, Gunzman et al. 1997 & others) • high mass galaxies with active star formation highest HI gas content? • SKA pathfinders observations test hypotheses Downsizing • the bulk of the stellar populations of the most massive galaxies formed at early times (Heavens et al. 2004, Thomas et al. 2005 & others) • the sites of active star formation shift from the high-mass galaxies at earliest times to the lower-mass galaxies at later periods (Cowie et al. 1996, Gunzman et al. 1997 & others) • high mass galaxies with active star formation highest HI gas content? • SKA pathfinders observations test hypotheses Downsizing • the bulk of the stellar populations of the most massive galaxies formed at early times (Heavens et al. 2004, Thomas et al. 2005 & others) • the sites of active star formation shift from the high-mass galaxies at earliest times to the lower-mass galaxies at later periods (Cowie et al. 1996, Gunzman et al. 1997 & others) • high mass galaxies with active star formation highest HI gas content? • use SKA pathfinders observations to test hypotheses Bonus Material Two Unusual Radio Continuum Objects in the Field of Abell 370 1. The DP Structure Single RC Single Radio Contiuum Source Double RC Double Radio Contiuum Source The DP Structure GMRT image resolution ~3.3 arcsec at 1040 MHz Peak flux = 1.29 mJy/Beam Total flux density ~ 23.3 mJy 60 arcsec across The DP Structure V band optical image from ANU 40 inch WFI 60 arcsec across The DP Structure Radio contours at 150, 300, 450, 600, 750, 900 & 1150 Jy/beam RMS ~ 20 Jy The DP Structure Optical as Contours The DP Structure Galaxies all at similar redshifts z ~ 0.3264 The DP Group The DP Group Abell 370 ~167 Mpc difference between cluster Abell 370 and DP group in commoving distance NOT related objects DP Group group well outside GMRT HI redshift range DP Structure Galaxy 4 – source of DP Structure The DP Group The DP Group 10 arcmin square box ~2800 kpc at z = 0.326 galaxy group/small cluster Explaining the Structure DP 1 a galaxy DP 2 pair of radio jets DP 3 DP 4 DP 5 galaxy moving through intercluster medium DP 6 DP 7 DP 8 currently I have the radio jets orientated along page with respect to the observer DP 9 changing orientation of the radio jets with respect to the observer DP 10 DP 11 2. A Radio Gravitational Arc? Radio Arc V band optical image from ANU 40 inch Abell 370 cluster 8 arcmin square Radio Arc V band optical image from ANU 40 inch Abell 370 cluster 8 arcmin square Radio Arc V band optical image from ANU 40 inch image centred on one of the two cD galaxies near the centre of the Abell 370 cluster 50 arcsec square Radio Arc optical image from Hubble Space Telescope optical arc in Abell 370 was the first detected gravitational lensing event by a galaxy cluster (Soucail et al. 1987) Radio Arc GMRT image resolution ~3.3 arcsec at 1040 MHz Peak flux = 490 Jy/Beam cD galaxy Peak flux = 148 Jy/Beam Noise ~20 Jy noise Radio Arc Radio contours at 80, 100, 120, 140, 180, 220, 260, 320, 380 & 460 Jy/beam RMS ~ 20 Jy Radio Arc Optical as Contours Conclusion Conclusion • one can use coadding with optical redshifts to make measurement of the HI 21-cm emission from galaxies at redshifts z > 0.1 • using this method the cosmic neutral gas density at z = 0.24 (look-back time of ~3 billion years) has been measured and the value is consistent with that from damped Lyα measurements • galaxy cluster Abell 370 at z = 0.37 (look-back time of ~4 billion years) has significantly more gas than similar clusters at z ~ 0 • the SKA pathfinders ASKAP and MeerKAT can measure the HI 21-cm emission from galaxies out to z = 1.0 (look-back time of ~8 billion years) using the coadding technique with existing optical redshift surveys