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Costa di Rovigo, Italy

Clemens M.S.,National institute for astrophysics | Negrello M.,National institute for astrophysics | De Zotti G.,National institute for astrophysics | De Zotti G.,International School for Advanced Studies | And 17 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2013

We combine Planck High Frequency Instrument data at 857, 545, 353 and 217 GHz with datafrom Wide-field Infrared Survey Explorer (WISE), Spitzer, IRAS and Herschel to investigatethe properties of a well-defined, flux-limited sample of local star-forming galaxies. A 545 GHzflux density limit was chosen so that the sample is 80 per cent complete at this frequency, andthe resulting sample contains a total of 234 local, star-forming galaxies. We investigate the dustemission and star formation properties of the sample via various models and calculate the localdust mass function. Although single-component-modified blackbodies fit the dust emissionlongward of 80 μm very well, with a median β = 1.83, the known degeneracy between dusttemperature and β also means that the spectral energy distributions are very well described bya dust component with dust emissivity index fixed at β = 2 and temperature in the range 10-25 K. Although a second, warmer dust component is required to fit shorter wavelength data, and contributes approximately a third of the total infrared emission, its mass is negligible. No evidence is found for a very cold (6-10 K) dust component. The temperature of the colddust component is strongly influenced by the ratio of the star formation rate to the total dustmass. This implies, contrary to what is often assumed, that a significant fraction of even theemission from ~20K dust is powered by ongoing star formation, whether or not the dust itselfis associated with star-forming clouds or 'cirrus'. There is statistical evidence of a free-freecontribution to the 217 GHz flux densities of ≲20 per cent. We find a median dust-to-stellarmass ratio of 0.0046; and that this ratio is anticorrelated with galaxy mass. There is goodcorrelation between dust mass and atomic gas mass (median Md/MHI = 0.022), suggestingthat galaxies that have more dust (higher values of Md/M*) have more interstellar medium ingeneral. Our derived dust mass function implies a mean dust mass density of the local Universe(for dust within galaxies), of 7.0 ± 1.4 × 105M⊙ Mpc-3, significantly greater than that foundin the most recent estimate using Herschel data. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Source

Negrello M.,National institute for astrophysics | Clemens M.,National institute for astrophysics | Gonzalez-Nuevo J.,Institute Of Fisica Of Cantabria Csic Uc | De Zotti G.,National institute for astrophysics | And 20 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2013

The Planck Early Release Compact Source Catalogue (ERCSC) has offered the first opportunity to accurately determine the luminosity function of dusty galaxies in the very local Universe (i.e. distances ≲ 100 Mpc), at several (sub-)millimetre wavelengths, using blindly selected samples of low-redshift sources, unaffected by cosmological evolution. This project, however, requires careful consideration of a variety of issues including the choice of the appropriate flux density measurement, the separation of dusty galaxies from radio sources and from Galactic sources, the correction for the CO emission, the effect of density inhomogeneities and more. We present estimates of the local luminosity functions at 857 GHz (350 μm), 545 GHz (550 μm) and 353 GHz (850 μm) extending across the characteristic luminosityL, and a preliminary estimate over a limited luminosity range at 217 GHz (1382 μm). At 850 μm and for luminosities L ≲ L* our results agree with previous estimates, derived from the Submillimeter Common-User Bolometer Array (SCUBA) Local Universe Galaxy Survey, but are higher than the latter at L ≲ L*. We also find good agreement with estimates at 350 and 500 μm based on preliminary Herschel survey data. © 2012 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Source

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