HOPCAT 6 d F Star Formation Rates Marianne

HOPCAT, 6 d. F & Star Formation Rates Marianne T. Doyle Ph. D. Project

Content Supervisor: Michael J. Drinkwater – UQ Assoc. Supervisors: Elaine Sadler – Uni Sydney John Ross - UQ Collaborators David J. Rohde - UQ Mike Read – WFAU Edinburgh Baerbel Koribalski – ATNF, Epping ¶Investigate the question: How does star HIPASS Team – ATNF Parkes & Epping, Universities of formation depend upon environment and : Melbourne, Cardiff, Western Sydney Macarthur, Wales, other factors? Swinburne, Technology Sydney, New Mexico, ¶Finding optical counterparts for the HIPASS Manchester, Colorado, Sydney, Leicester catalogue ASTRON The Netherlands, ¶Investigating the Morphology-density AAO Sydney, WIYN Tucson relation using Star Formation Rates, Star etc…. . . . ¶ The HIPASS - 6 d. FGS Connection ¶ My Project Formation Efficiency and Galaxy Density

The 6 d. FGS - HIPASS Connection ¶ HI Parkes Sky Survey (HIPASS) ¶ HI blind radio survey of the southern sky up to Dec=2 o ¶ October 2001: 2710 “additional” targets were added to the 6 df. GS (Thank you Michael Drinkwater) ¶ Optical objects included are: ¶ within 5 arcmin of the HIPASS positions ¶R mag < 17 ¶“NOT” already in one of the official optical target lists for 6 d. F ¶ 341 - highest priority: multiple matches to radio position 1558 - main sample 811 - faint sample (16. 7<R<17)

My Ph. D Project ¶ The question: How does the conversion of hydrogen to stars (star formation) depend upon environment and other factors? ¶ Testing two theories: ¶ Either fewer “star forming galaxies” actually form in regions of high galaxy density, OR ¶ There are physical processes that directly suppresses star formation.

Steps ¶ Use radio detected galaxy sample instead of optical sample ¶ Optical samples are biased towards star forming galaxies which is what we are trying to measure. ¶ Star Formation Rate (SFR) ¶ Star Formation Efficiency (SFE) ¶ Local galaxy density

Optical Counterpart - HOPCAT ¶ HIPASS Catalogue (HICAT) contains 4315 HI radio sources ¶ Find optical counterparts ¶ Accurate galaxy position needed to measure luminosity to calculate SFR ¶ Search for “Dark Galaxies”

Optical Data ¶ OPTICAL IMAGES ¶ Super. COSMOS 15’ x 15’ Images ¶ 7’ radius Radio-Optical position uncertainty Radio-Optical Position Uncertainty ¶ IMAGE ANALYSIS ¶ SExtractor Image Analysis.

Is that the right galaxy? ¶ Many images have multiple galaxies ¶ Crosscheck HIPASS velocity with optical or high resolution radio velocities ¶ Published velocities – NED ¶Information from catalogues, surveys & the literature Data varies in quality ¶ Need a high quality dataset Unobserved areas ¶ 6 d. F velocities (Kindly supplied by Heath) ¶ Developed an automated visual interactive program ADRIC

Results ¶ Optically Matched with velocity 58% 2516 26% 1107 11% 476 5% 216 ¶ Single Match (44% - 1882) ¶ Compact group member (14% - 634) ¶ Optically Matched with no velocity ¶ Single Match (20% - 851) ¶ Compact group member (6% - 256) ¶ No Guess ¶ Several galaxies no velocities ¶ Blank Field ¶ No visible galaxy

Any Isolated Dark Galaxies in HIPASS? ¶ ¶ ¶ 4315 HI detected objects Extinction cut at ABj < 1 - 3692 objects Use only blank fields - 13 objects Take out over crowded fields - 2 object remaining 2 remaining objects? ¶ 1 is a very faint previously observed galaxy in the Centaurus group ¶ 1 ruled out with Narrow-band follow-up observations at Parkes as a non-detection ¶ Conclusion: No isolated dark galaxies are present in the HIPASS survey

HOPCAT’s Galaxy density coverage ¶ Solution? ¶ Galaxies in regions with¶Low galaxy ATCA high resolution HI observations to density? find/confirm optical counterpart in regions of high density ¶ galaxy Large sample ¶ Galaxies in regions with High galaxy density? ¶ Very small sample

Star Formation & Density ¶ SUMSS radio continuum data ¶ 304 Sumss – HOPCAT matches ¶ Galaxy Density ¶ 10 th Galaxy radius ¶ Galaxy number / degree 2 ¶ Star Formation Rate ¶ Star Formation Efficiency

Ave density = 86 Ave SFR density = 12 Ave = 1. 2 Ave SFR = 0. 5 Star Formation Rate Vs Density Ave density =0. 9 Ave SFR = 0. 34 Ave density=0. 07 SFR ave=1. 3

Star Formation Efficiency Vs Density ¶ SUMSS – Sydney University Molonglo Sky Survey ¶ 304 Sumss – HOPCAT matches ¶ Galaxy Density ¶ 10 th Galaxy radius ¶ Galaxy number / degree 2

Summary ¶ 2710 optical galaxies near HIPASS positions were added to the 6 d. FGS list

ADRIC interactive visual matching program Original HICAT parameters 15 x 15 arcmin images to allow for the 7 arcmin position uncertainty Centred on HICAT positions Superimposed ellipses and listed Yellow for Published correct match velocities Selection parameters