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THE UNIVERSITY OF QUEENSLAND Star Formation Efficiency and Environment Marianne T. *1, Doyle 1 Drinkwater , 1 Rohde , David J. Michael J. Mike 3 Koribalski and The HIPASS Team 2 Read , Baerbel S 1. Department of Physics, University of Queensland, Brisbane, Queensland 4072, Australia. 2. WFAU, Institute for Astronomy, Royal Observatory, Blackford Hill Edinburgh, EH9 3HJ, UK 3. ATNF, PO Box 76 Epping NSW 1710 Australia Email: [email protected] SUMMARY OPTICAL COUNTERPARTS OF HIPASS SOURCES New HIPASS Optical Catalogue (HOPCAT) Optical counterparts for the HI Parkes All-Sky 21cm Survey (HIPASS) (1) have been identified using SuperCOSMOS optical sky survey images Input Data Radio: HIPASS catalogue (HICAT) (2) - 4329 sources Optical: SuperCOSMOS (3): Optical images SExtractor (4): new image catalogue with BRI photometry 6dF Galaxy Survey (5): velocity matching NED Database (6): velocity matching Using the new optical sample we will investigate Estimators of Star Formation Rates (SFR) Dependence of Star Formation on local galaxy density Matching Process – ADRIC ADRIC: Matlab Program to display and select optical data for each HIPASS source Velocities from the NED Database and the 6dF Galaxy Survey were used to match those for the HIPASS radio sources to confirm optical matches When no velocities were available proximity to the HIPASS co-ordinates and other image features were used to assist optical matching Log HIPASS Peak Flux Vs Optical Apparent Magnitude for objects matched by velocities from NED and 6dF, educated guesses without velocity match and velocity matches where multiple galaxies match. Results Analysis of 4329 Radio Sources 78% identified Velocity Match 57% With published velocity Good Guesses 10% But no published velocity Multi Match 11% Compact group of galaxies No Guess 15% Several galaxies no velocities Blank Field 7% Screen shot of the ADRIC program showing 15’ SuperCOSMOS field centred on a HICAT source, with published velocities in red, blue ellipses from SExtractor catalogue (selected galaxy in purple). The buttons classify the selected optical counterpart (allowing cases of poor photometry due to merged objects or poor image segmentation to be noted). Log Mass HI Vs Log Luminosity for objects matched by velocities from NED and 6dF, educated guesses without velocity match and velocity matches where multiple galaxies match. Skyplot of the position of each HIPASS radio source co-ordinates. Note the concentration of “blank fields” in the Galactic Plane. Position offsets: Radio - Optical Position offset (RA) vs Peak Radio Flux Velocity offsets: Radio – Optical vs Peak Flux STAR FORMATION AND ENVIRONMENT Star Formation Estimators 5 4 Future Work 3 2 1 0 -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 B-R 6dF Hα Equivalent Width Vs B-R References 1. 2. 3. 4. 5. Stavely-Smith et al (2001) Stavely-Smith, Lister, 2001, MNRAS, 322, Zwaan & Meyer et al (in preparation) Hambly et al, 2001, MNRAS, 326,1279-1294,1295-1314,1315-1327 Bertin E., Arnouts S., AASS, (1996) 117, 393-404 Wakamatsu, K., Colless M.M., Jarrett T., Parker Q., Saunders W. and Watson F., 2002, IAU Regional Assembly, ASP Conf. Series (in press) 6. Madore Barry F., Helou George, Corwin Harold G. Jr.,Schmitz Marion, Wu Xiuqiv and Bennett Judy, 1992, ADASS I ASP Conf Series, 25 Background: M83: The Southern Pinwheel Galaxy from VLT, FORS Team, 8.2-meter VLT, ESO, http://antwrp.gsfc.nasa.gov/apod/ap030511.html 0.6 Estimators of TOTAL Star Formation Rate to be investigated: Radio Continuum High resolution radio observations HIPASS continuum catalog in preparation Mid Infrared Correlation of SFR with local galaxy density Tentative evidence that galaxies in highdensity regions are redder (see figure) 3.5 3 2.5 (Local/HIPASS) Density ) Alpha Log Eq Width (H Hα emission line equivalent width from 6dF Galaxy Survey shows expected weak correlation with colour 6dF spectra measured using 7 arcsec fibres Measure only the centre of the galaxy 6 2 1.5 1 0.5 0 -1.5 -1 -0.5 0 0.5 1 B-R Density Ratio Vs B-R for 6dF Galaxy Survey observation -22< dec <-42. Density ratio: ratio of galaxy density within a 10MParsec radius for each optically matched galaxy to the galaxy density of HICAT within 5MParsec radius volumes IAU SYMPOSIUM 216 - MAPS OF THE COSMOS – 14 -17 JULY XXV\TH GENERAL ASSEMBLY, SYDNEY JULY 13-26, 2003