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ASKAP Continuum Surveys of Local Galaxies Michael Brown ARC Future Fellow Monash University.

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Presentation on theme: "ASKAP Continuum Surveys of Local Galaxies Michael Brown ARC Future Fellow Monash University."— Presentation transcript:

1 ASKAP Continuum Surveys of Local Galaxies Michael Brown ARC Future Fellow Monash University

2 Where are we now? NVSS / FIRST / SUMMS 0.5 mJy RMS per beam 15”-1’ beam ~30 uJy RMS per beam in 12 hours Future ASKAP 12

3 K<9 Spiral Galaxies Catalogued sources Flux density per beam from NVSS images

4 K<9 Early-type Galaxies Brown et al. 2011

5 K<10.5 Spiral Galaxies & AGNs Floyd et al. (submitted)

6 Radio continuum Continuum detects “hot mode” AGNS. Continuum can be a good SFR indicator – Have we been misled by optical colours? – Are SFR indicators properly calibrated? ASKAP ADE-12 is great for low z science! – It will detect all* local galaxies (duty cycles, env). – One galaxy per beam and with known locations. – Spectroscopy, morphology, optical, mid-IR Done better with completed ASKAP but…

7 Galaxy Colour Bimodality

8 Galaxy Evolution

9 Bonne et al. (in prep.) K-band Absolute Magnitude Red Spiral / Total Spiral

10 Kennicutt et al. 2009 Corrected L H  L 1.4 L 1.4 & L H  SFR Indicator

11 Rescaling Spectra Spectra and H- alpha measurements from Moustakas et al. (2006, 2010) need to be increased by 10%.

12 UGCA 219 NVSS 4.5 mJy Optical g=14.78

13 UGCA 166 g~16 NVSS 2.0 mJy Optical g=16.05

14 Dolley et al. (in prep.) High star-formation Low star-formation Galaxy Clustering Strength Projected spatial Scale

15 Are Red Spirals Forming Stars? K AB <10.5 spiral galaxies – Bonne et al. (in prep) and Floyd et al. (sub.) NVSS 1.4 GHz as a star formation proxy – 1.4 GHz is not impacted by dust obscuration WISE mid-IR to search for warm dust – Dust is heated by star formation 21-cm to search for neutral hydrogen – Could star formation resume?

16 Sample Selection K AB <10.5 T-type > -1 NVSS 1.4 GHz coverage 228 galaxies Select galaxies with f 1.4 < 2.5 mJy 42 galaxies

17 SDSS Optical Colours K AB <10.5 f 1.4 <2.5 mJy All other spiral galaxies

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19 UV-optical similar to passive E H-alpha lost in the noise Spiral arms are blue in UV-optical IR excess Red and no NVSS, but Star Forming

20 Radio continuum Continuum detects “hot mode” AGNS. Continuum can be a good SFR indicator – Have we been misled by optical colours? – Are SFR indicators properly calibrated? ASKAP ADE-12 is great for low z science! – It will detect all* local galaxies (duty cycles, env). – One galaxy per beam and with known locations. – Spectroscopy, morphology, optical, mid-IR Done better with completed ASKAP but…

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22 NGC 2811 f 1.4 < 2.5 mJy X

23 Summary Have we been misled by colour bimodality? Red spirals are not faded blue spirals. – Red spirals are brighter than blue spirals (Bonne). High and low SFR spirals live in similar halos – The large-scale clustering is similar (Dolley). Low SFR spirals are not passive spirals – Infrared excess and PAH emission Red spirals generally have HI

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26 NVSS WISE 11 microns Spitzer 24 microns SDSS Optical

27 Infrared SEDs IR excess relative to passive elliptical galaxies NGC 4725 spectrum shows PAH and dust emission

28 21-cm Catalogued HI in red Uncatalogued HI in black 228 spirals with K AB < 10.5 186 spirals in HI catalogues 42 spirals f 1.4 < 2.5 mJy 31 spirals in HI catalogues

29 NGC 5188 f 1.4 =95 mJy X

30 NGC 7727 f 1.4 <2.5 mJy X


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