S urveys of Local Galaxies Michael Brown ARC Future Fellow Monash University Where are we now NVSS FIRST SUMMS 05 mJy RMS per beam 151 beam 30 uJy RMS per beam in 12 hours ID: 344199
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ASKAP Continuum Surveys of Local Galaxies
Michael BrownARC Future FellowMonash UniversitySlide2
Where are we now?NVSS / FIRST / SUMMS0.5 mJy RMS per beam15”-1’ beam~30 uJy RMS per beam in 12 hours
Future ASKAP 12Slide3
K<9 Spiral Galaxies
Catalogued sources
Flux density per
beam from NVSS imagesSlide4
K<9 Early-type Galaxies
Brown et al. 2011Slide5
K<10.5 Spiral Galaxies & AGNs
Floyd et al. (submitted)Slide6
Radio continuumContinuum detects “hot mode” AGNS.Continuum can be a good SFR indicatorHave 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-
IRDone better with completed ASKAP but…Slide7
Galaxy Colour BimodalitySlide8
Galaxy EvolutionSlide9
Bonne et al. (in prep.)K-band Absolute MagnitudeRed Spiral / Total SpiralSlide10
Kennicutt et al. 2009Corrected L HaL
1.4L 1.4 & L HaSFRIndicatorSlide11
RescalingSpectraSpectra and H-alpha measurements from Moustakas et al. (2006, 2010) need to be increased by 10%.Slide12
UGCA 219NVSS 4.5 mJy Optical g=14.78Slide13
UGCA 166 g~16NVSS 2.0 mJy Optical g=16.05Slide14
Dolley et al. (in prep.)High star-formationLow star-formation
Galaxy Clustering StrengthProjected spatial ScaleSlide15
Are Red Spirals Forming Stars?KAB<10.5 spiral galaxiesBonne et al. (in prep) and Floyd et al. (sub.)NVSS 1.4 GHz as a star formation proxy1.4 GHz is not impacted by dust obscurationWISE mid-IR to search for warm dustDust is heated by star formation21-cm to search for neutral hydrogenCould star formation resume?Slide16
Sample SelectionKAB<10.5T-type > -1NVSS 1.4 GHz coverage228 galaxiesSelect galaxies with f1.4
< 2.5 mJy42 galaxiesSlide17
SDSS Optical ColoursKAB<10.5 f1.4<2.5
mJyAll other spiral galaxiesSlide18Slide19
UV-optical similar to passive EH-alpha lost in the noiseSpiral arms are blue in UV-opticalIR excessRed and no NVSS, but Star FormingSlide20
Radio continuumContinuum detects “hot mode” AGNS.Continuum can be a good SFR indicatorHave 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-
IRDone better with completed ASKAP but…Slide21Slide22
NGC 2811 f1.4 < 2.5 mJyXSlide23
SummaryHave 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 halosThe large-scale clustering is similar (Dolley).Low SFR spirals are not passive spiralsInfrared excess and PAH emission Red spirals generally have HISlide24Slide25Slide26
NVSSWISE 11 microns
Spitzer 24 micronsSDSS OpticalSlide27
Infrared SEDsIR excess relative to passive elliptical galaxiesNGC 4725 spectrum shows PAH and dust emissionSlide28
21-cmCatalogued HI in redUncatalogued HI in black228 spirals with KAB < 10.5186 spirals in HI catalogues42 spirals f
1.4 < 2.5 mJy31 spirals in HI cataloguesSlide29
NGC 5188 f1.4=95 mJyXSlide30
NGC 7727 f1.4<2.5 mJyX