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ASKAP Continuum S urveys of Local Galaxies

ASKAP Continuum S urveys of Local Galaxies. Michael Brown ARC Future Fellow Monash University. 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. K<9 Spiral Galaxies. Catalogued sources Flux density per

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ASKAP Continuum S urveys of Local Galaxies

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  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.) Red Spiral / Total Spiral K-band Absolute Magnitude

  10. SFRIndicator L 1.4 L 1.4 & L Ha Kennicutt et al. 2009 Corrected L Ha

  11. RescalingSpectra 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? • KAB<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 KAB<10.5 T-type > -1 NVSS 1.4 GHz coverage 228 galaxies Select galaxies with f1.4 < 2.5 mJy 42 galaxies

  17. SDSS Optical Colours KAB<10.5 f1.4<2.5 mJy All other spiral galaxies

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

  19. 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…

  20. NGC 2811 f1.4 < 2.5 mJy X

  21. 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

  22. NVSS WISE 11 microns Spitzer 24 microns SDSS Optical

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

  24. 21-cm Catalogued HI in red Uncatalogued HI in black 228 spirals with KAB < 10.5 186 spirals in HI catalogues 42 spirals f1.4 < 2.5 mJy 31 spirals in HI catalogues

  25. NGC 5188 f1.4=95 mJy X

  26. NGC 7727 f1.4<2.5 mJy X

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