HOPCAT, 6dFGS & Star Formation Rates THE MORPHOLOGY-DENSITY RELATION IS THE OBSERVATAION THAT THERE ARE FEW OF THESE SPIRAL GALAXIES IN AREAS OF HIGH GALAXY DENSITY WHAT WE ARE LOOKING AT IS WHY WE DON’T SEE THESE IN GALAXY DENSE REGIONS Marianne T. Doyle Ph.D. Project

Swinburne Galaxy Groups Workshop 24th & 25th May, 2005 Content Advisor: Michael J. Drinkwater – UQ Assoc. Advisors: Elaine Sadler – Uni Sydney John Ross - UQ Collaborators David J. Rohde - UQ Mike Read – WFAU Edinburgh Baerbel Koribalski – ATNF, Epping HIPASS Team – ATNF Parkes & Epping, Universities of : Melbourne, Cardiff, Western Sydney Macarthur, Wales, Swinburne, Technology Sydney, New Mexico, Manchester, Colorado, Sydney, Leicester ASTRON The Netherlands, AAO Sydney, WIYN Tucson etc…....... The HIPASS - 6dFGS Connection My PhD Project & 6dFGS Investigate the question: How does star formation depend upon environment and other factors? Part 1: Finding optical counterparts for the HIPASS catalogue Part 2: Investigate the 2 possible explanations for the Morphology-density Relation using Star Formation Rates, Star Formation Efficiency and Galaxy Density Swinburne Galaxy Groups Workshop 24th & 25th May, 2005

The 6dFGS - HIPASS Connection HI Parkes Sky Survey (HIPASS) HI blind radio survey of the southern sky up to Dec=+2o Velocity range of 300 to 12700 km s-1 October 2001: 2710 “additional” targets were added to the 6dFGS (Thank you Mike Read & Michael Drinkwater) Optical objects included are: within 5 arcmin of the HIPASS positions R < 17 mag “NOT” already in one of the official optical target lists for 6dFGS 341 - highest priority: multiple matches to radio position 1558 - main sample 811 - faint sample (16.7 < R < 17) HIPASS BLIND SURVEY OF THE SOUTHERN SKY HIPASS CATALOGUE (HICAT) COVERS HI DETECTIONS OUT TO 300 to 12700KM/S Swinburne Galaxy Groups Workshop 24th & 25th May, 2005

Swinburne Galaxy Groups Workshop 24th & 25th May, 2005 My PhD 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. FIND NO STAR FORMING GALAXIES OR VERY FEW IN GALAXY DENSE REGIONS FIRST PROVED FIND HI BUT NO STAR FORMATION THEN 2ND IS RIGHT Swinburne Galaxy Groups Workshop 24th & 25th May, 2005

Swinburne Galaxy Groups Workshop 24th & 25th May, 2005 Steps Part 1 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. Find optical counterparts for radio sample Part 2 Star Formation Rate (SFR) Star Formation Efficiency (SFE) Local galaxy density Which theory is correct to explain the Morphology-density relation OPTICAL SAMPLE BIASED TOWARD STAR FORMING GALAXIES WHICH IS WHAT WE ARE MEASURING RADIO GIVES A WIDER COVERAGE OF GALAXY TYPES SFR FROM LUMINOSITIES SFE SFR / MASS HI LOCAL GALAXY DENSITY FIND NO STAR FORMING GALAXIES OR VERY FEW IN GALAXY DENSE REGIONS FIRST PROVED FIND HI BUT NO STAR FORMATION THEN 2ND IS RIGHT Swinburne Galaxy Groups Workshop 24th & 25th May, 2005

1st Part: Optical Counterpart - HOPCAT HIPASS Catalogue (HICAT) contains 4315 HI radio sources Parkes beam 15’ - Radio-Optical position uncertainty 7’ Find optical counterparts Accurate optical positions are needed to measure luminosity to estimate SFR Search for Isolate Dark Galaxies HI source containing gas (and dark matter) No detectable stars Sufficiently far away from other galaxies, groups or clusters “HI SOURCE CONTAINING GAS (AND DARK MATTER) NO DETECTABLE STARS SUFFICIENTLY FAR AWAY FROM OTHER GALAXIES, GROUPS OR CLUSTERS SUCH THAT A TIDAL ORIGIN CAN BE EXCLUDED” Swinburne Galaxy Groups Workshop 24th & 25th May, 2005

Radio-Optical Position Uncertainty Optical Data OPTICAL IMAGES SuperCOSMOS 15’ x 15’ Images Parkes beam is 15’ 7’ radius Radio-Optical position uncertainty IMAGE ANALYSIS SExtractor Image Analysis. OPTICAL IMAGES: RADIO–OPTICAL UNCERTAINTY HIPASS SURVEY HAS 15’ BEAM WANTED IMAGE BIG ENOUGH TO COVER GALAXY GROUPS NOT CUT OF EDGES OF LARGER GALAXIES QUICK TEST SHOWED OPTICAL MATCH CAN BE UP TO 7’ FROM HICAT POSITION Swinburne Galaxy Groups Workshop 24th & 25th May, 2005

Is that the right galaxy? Unobserved areas Visually matched by 3 people to minimise galaxy selection bias Is that the right galaxy? Many images have multiple galaxies Crosscheck HIPASS velocity with: High quality dataset - 6dFGS velocities (Kindly supplied by Heath) Published velocities – NED Information from catalogues, surveys & the literature Data varies in quality Developed ADRIC Automated visual interactive program Swinburne Galaxy Groups Workshop 24th & 25th May, 2005

Swinburne Galaxy Groups Workshop 24th & 25th May, 2005 Results Optical counterparts for 84% of HICAT radio sources Optically Matched with velocity 58% 2512 Single Match (42% - 1798) Compact group member (16% - 714) Optically Matched with no velocity 26% 1106 Single Match (20% - 848) Compact group member (6% - 258) No Guess 11% 481 Several galaxies no velocities Blank Field 5% 216 No visible galaxy GO THROUGH THE NUMBERS AND EXPLAIN CATAGORIES CLASSIFICATION ERROR - EACH IMAGES VIEWED BY 3 PEOPLE AND THE UNANIMOUS % IS LISTED Swinburne Galaxy Groups Workshop 24th & 25th May, 2005

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 – Banks et al (1999) 1 ruled out with Narrow-band follow-up observations at Parkes as a non-detection (Thank you Ivy) Conclusion: No isolated dark galaxies are present in the HIPASS survey Doyle et al. (MNRAS in press) Swinburne Galaxy Groups Workshop 24th & 25th May, 2005

Part 2: Star Formation & Density (Preliminary work) First Pass: Sydney University Molonglo Sky Survey (SUMSS) 843MHz radio continuum data 304 SUMSS – HOPCAT matches Star Formation Rate Star Formation Efficiency Galaxy Density Galaxy separation between HICAT & SuperCOSMOS Galaxy Catalogue positions Area based on a radius to the 10th nearest galaxy Galaxy number / degree2 Swinburne Galaxy Groups Workshop 24th & 25th May, 2005

HOPCAT’s Galaxy density coverage Solution? ATCA high resolution HI observations to find/confirm optical counterpart in regions of high galaxy density Solution? ATCA high resolution HI observations to find/confirm optical counterpart in regions of high galaxy density Swinburne Galaxy Groups Workshop 24th & 25th May, 2005

Swinburne Galaxy Groups Workshop 24th & 25th May, 2005 AS EXPECTED - LARGER THE MHI, HIGHER THE SFR Swinburne Galaxy Groups Workshop 24th & 25th May, 2005

Swinburne Galaxy Groups Workshop 24th & 25th May, 2005 Distribution of SFR/unit Luminosity - Cluster & Field samples (Lewis et al. 2002) Cluster sample limited to galaxies within the virial radius Lewis et al. (2002) Field galaxies have a higher SFR than those in the clusters Swinburne Galaxy Groups Workshop 24th & 25th May, 2005

Swinburne Galaxy Groups Workshop 24th & 25th May, 2005

Swinburne Galaxy Groups Workshop 24th & 25th May, 2005

Swinburne Galaxy Groups Workshop 24th & 25th May, 2005 SUMMARY Positions for 2710 optical galaxies near HIPASS positions added to 6dFGS observing list HIPASS Optical Catalogue Used 6dFGS velocities Optical Counterparts for 84% Preliminary Work - SUMSS SFR vs. HI mass : Larger the HI mass the larger the SFR SFR vs. Density : Decreased SFR in galaxy dense regions? More analysis needed SFE vs. Density : Decreased SFE in galaxy dense regions? More analysis needed 1. (A) SFR FROM LUMINOSITIES = INFRARED, RADIO CONTINUUM & Sub sample of H-Alpha (B) LOCAL GALAXY DENSITY MEASURE - 3D & to 10th galaxy density – more work to do 3. (A) SFE - Formula 4. HOW DOES THE CONVERSION OF HYDROGEN TO STARS DEPEND UPON ENVIRONMENT AND OTHER FACTORS? EITHER - FEWER SF GALAXIES IN REGIONS OF HIGH DENSITY OR - THERE IS A PHYSICAL PROCESS THAT DIRECTLY SUPPRESSES SF IF NO DECREASE IN SF = GALAXIES OF DIFFERENT TYPES, WITH FEWER STAR FORMING GALAXIES, FORM IN REGIONS OF HIGH DENSITY. IF THERE IS A DECREASE IN SF IN REGIONS OF HIGH DENSITY = THEN THE THEORY THAT THERE IS A PHYSICAL PROCESS THAT DIRECTLY SUPPRESSES STAR FORMATION IS SUPPORTED. !!!!!BUT WE HAVE ATCA OBSERVATIONS IN FEB/MARCH 2005 – VOLUNTEERS?????? Swinburne Galaxy Groups Workshop 24th & 25th May, 2005

Future Data Resources for SFR Calculations IRAS 2MASS HIPASS Continuum 6dFGS Hα SINGG Hα Survey Gerhardt Meurer, Johns Hopkins University Complete Hα imaging for small subset of HIPASS Swinburne Galaxy Groups Workshop 24th & 25th May, 2005

15 x 15 arcmin images to allow for the 7 arcmin position uncertainty ADRIC interactive visual matching program Selection parameters 15 x 15 arcmin images to allow for the 7 arcmin position uncertainty Original HICAT parameters Superimposed and listed Published velocities Superimposed ellipses Yellow for correct match Centred on HICAT positions SCREEN SHOT OF THE ADRIC PROGRAM HICAT PARAMETERS FIELD CENTRED ON A HICAT SOURCE 15 ARCMIN SQUARE IMAGE – ~7ARCMIN HIPASS POSITION UNCERTAINITY IMAGES ANALYISED AND FROM DATA ELLIPSES PRODUCED (SELECTED GALAXY IN YELLOW). WITH 2 SOURCES OF PUBLISHED VELOCITIES THE BUTTONS CLASSIFY THE SELECTED TYPE OF OPTICAL COUNTERPART & QUALITY ALLOWING CASES OF POOR PHOTOMETRY – STAR INSIDE ELLIPSES POOR IMAGE SEGMENTATION – ELLIPSE NOT ENCAPUTLAING THE WHOLE GALAXY Swinburne Galaxy Groups Workshop 24th & 25th May, 2005

Swinburne Galaxy Groups Workshop 24th & 25th May, 2005 Analysis of SuperCOSMOS Images SExtractor Image Analysis SuperCOSMOS data catalogue? Ellipse segmentation problem for extended objects SExtractor Segmentation problems? Used 2 sets of ellipse analysis parameters Swinburne Galaxy Groups Workshop 24th & 25th May, 2005