HI at moderate redshifts Philip Lah Science with MIRA workshop Research School of Astronomy & Astrophysics Mount Stromlo Observatory

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 z  0.2 my result for HI in star-forming galaxies at z=0.24 The Future what MIRA can do

The Past

Why HI detection is hard z=0.05

Older HI emission at moderate redshifts

HI emission detections Zwaan et al z =  galaxy in the outskirts of galaxy cluster Abell 2218  WSRT 200 hours Verheijen 2004 z =  galaxy in the outskirts of galaxy cluster Abell 2192  VLA ~80 hours

The Present

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 ClusterAbell 2192Abell 963 redshift Look-backtime2.28 Gyr2.47 Gyr Integration Time180 hrs240 hrs Noise Level91 μJy/beam68 μJy/beam HI Detections3020 Secure Detections (optical counterparts in SDSS) 2217 HI masses detected range between 5  10 9 M  and 4  M  (0.8 M* to 6.3 M*)

z= An example galaxy in Abell 2192

HI Coadded Signal For both clusters, galaxies in surrounding field with optical redshifts M HI = 2  10 9 M  no HI detection

HI in star-forming galaxies at z=0.24

Collaborators: Frank Briggs (ANU) Jayaram Chengalur (NCRA) Matthew Colless (AAO) Roberto De Propris (CTIO) Michael Pracy (ANU) Erwin de Blok (ANU)

Giant Metrewave Radio Telescope

The Suprime-Cam Field RA DEC 24’ × 30’ Fujita et al narrow band imaging - H  emission at z= galaxies SFRD z=0.24 ~ 3  SFRD z=0

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

GMRT data for the field GMRT Observation Time Useful Time on Field 80.5 hours~40 hours Primary Beam Size Synthesis Beam Size ~29’ ~2.9’’ Instantaneous Bandwidth Number of Channels Channel Bandwidth Channel Width 32 MHz 2 × kHz 32.6 kms -1 Observing Frequency HI Redshift 1150 MHz 0.24 RMS per channel Continuum RMS ~130  Jy15  Jy

Coadded HI Spectrum

HI spectrum all neutral hydrogen gas measurement using 121 redshifts M HI = (2.26 ± 0.90) ×10 9 M  0.36 ± 0.14 M*

The Cosmic Neutral Gas Density

Zwaan et al HIPASS HI 21cm Rao et al DLAs from MgII absorption Prochaska et al DLAs Cosmic Neutral Gas Density vs. Redshift

my new point Cosmic Neutral Gas Density vs. Redshift

Cosmic Neutral Gas Density vs. Time my new point

The Future

MIRA: Frequency Parameters frequency coverage from MHz  HI from z=0 to 1 instantaneous bandwidth is 300 MHz Frequency Range Redshift Range Look-backtime range MHz Gyr MHz Gyr

MIRA HI Coadding

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 SkyMapper 1.3m telescope  8 sq degree field of view - operational sometime later this year

The End