400 likes | 529 Views
Research School of Astronomy & Astrophysics. Mount Stromlo Observatory. HI at moderate redshifts Philip Lah Science with MIRA workshop. What do I mean by “HI at moderate redshifts” ??. HI 21cm emission from galaxies with z > 0.08 look-backtime > 1 Gyr
E N D
Research School of Astronomy & Astrophysics Mount Stromlo Observatory HI at moderate redshiftsPhilip LahScience with MIRA workshop
What do I mean by “HI at moderate redshifts” ?? HI 21cm emission from galaxies with z > 0.08 look-backtime > 1 Gyr Enough time for significant cosmological evolution in galaxies
Talk Outline The Past • why HI emission detection is hard at moderate redshifts • older HI emission galaxy detections The Present • recent WSRT HI detections of galaxies in clusters at z0.2 • my result for HI in star-forming galaxies at z=0.24 The Future • what MIRA can do
Why HI detection is hard z=0.05
HI emission detections • Zwaan et al. 2001 z = 0.176 • galaxy in the outskirts ofgalaxy cluster Abell 2218 WSRT 200 hours • Verheijen 2004 z = 0.1887 • galaxy in the outskirts of galaxy cluster Abell 2192 VLA ~80 hours
WSRT Cluster Survey Verheijen et al. January 2007 – results from a completed pilot study of two galaxy clusters • Abell 2192 z=0.188 (1196 MHz) • Abell 963 z=0.206 (1178 MHz)
Observations Details HI masses detected range between 5109 M and 41010 M (0.8 M* to 6.3 M*)
An example galaxy in Abell 2192 z=0.1888
HI Coadded Signal no HI detection For both clusters, galaxies in surrounding field with optical redshifts MHI= 2109 M
Collaborators:Frank Briggs (ANU) Jayaram Chengalur (NCRA) Matthew Colless (AAO)Roberto De Propris (CTIO)Michael Pracy (ANU)Erwin de Blok (ANU)
The Suprime-Cam Field 24’ × 30’ Fujita et al. 2003 narrow band imaging - H emission at z=0.24 348 galaxies SFRDz=0.24 ~ 3 SFRDz=0 RA DEC
Fujita galaxies - B filter thumbnails 10 arcsec 10 arcsec ordered by increasing H luminosity
Fujita galaxies – 2dF redshifts thumbnails 10 arcsec 10 arcsec ordered by increasing H luminosity
neutral hydrogen gas measurement using 121 redshifts MHI = (2.26 ± 0.90) ×109 M 0.36 ± 0.14 M* HI spectrum all
Cosmic Neutral Gas Density vs. Redshift Rao et al. 2006 DLAs from MgII absorption Prochaska et al. 2005 DLAs Zwaan et al. 2005 HIPASS HI 21cm
Cosmic Neutral Gas Density vs. Redshift my new point
Cosmic Neutral Gas Density vs. Time my new point
MIRA: Frequency Parameters • frequency coverage from 700 - 1700 MHz HI from z=0 to 1 • instantaneous bandwidth is 300 MHz
MIRA: coadding HI signal observational constraint is the number of optical redshifts available redshift bins Δz =0.025
MIRA: coadding HI signal observational constraint is the number of optical redshifts available redshift bins Δz =0.025
MIRA: coadding HI signal observational constraint is the number of optical redshifts available redshift bins Δz =0.025
Future Optical Data AAOmega on AAT - ~3 sq degrees Wigglez Survey - due to be complete by 2009 • equation of state for dark energy from baryonic acoustic oscillations in galaxy clustering • redshift survey of 400,000 galaxies with active star formation z =0.5 to 1 over 1000 sq degrees • 10+ fields each ~81 sq degrees 400 targets/sq degree ANU SkyMapper1.3m telescope 8sq degreefield of view- operational sometime later this year