Astronomy and Astrophysics – Astrophysics – Cosmology and Extragalactic Astrophysics
Scientific paper
2009-09-09
Astronomy and Astrophysics
Astrophysics
Cosmology and Extragalactic Astrophysics
14 pages, 11 figures, accepted for publication in Astronomy and Astrophysics
Scientific paper
Polycyclic aromatic hydrocarbon (PAH) emission has been found in both starbursts and modestly starforming galaxies, but the relation between starforming activity and PAH luminosity is still a matter of debate. The different correlation degrees could be caused by the variety of optical and far-infrared sample selection criteria. In order to obtain a census of the typical properties of PAH emitting galaxies, we here study moderately distant galaxies which have been selected by their PAH emission. Combining the ISOCAM Parallel Survey at 6.7 micron with 2MASS we have colour-selected a sample of 120 candidates for strong PAH emission. We obtained optical and mid-infrared spectra of 75 and 19 sources, respectively, and analysed IRAS-ADDSCANs and available Spitzer 3.6-160 micron photometry. The Spitzer spectra exhibit clear PAH features and corroborate that our photometric selection criteria trace the PAH emission of galaxies fairly well. The optical spectra show emission lines, at median redshift z~0.1, as well as Hdelta and CaII absorption, indicating ongoing starformation as well as post-starbursts. The mid- and far-infrared spectral energy distributions (SEDs) provide evidence for a broad range of far-infrared (FIR) luminosities, but in general the dust is colder than for starburst galaxies like M82. For most galaxies the monocromatic luminosity peaks at about equal height at optical, 6.7 micron (PAH) and FIR wavelengths. In about 15% of the sources the FIR luminosity exceeds the optical and PAH energy output by about a factor 5-10 despite the cool dust temperature; in these galaxies a large dust mass of 10^8 - 10^9 M_sun is inferred.
Chini Rolf
Drass Holger
Haas Martin
Leipski Christian
Meusinger Helmut
No associations
LandOfFree
Polycyclic aromatic hydrocarbon selected galaxies does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Polycyclic aromatic hydrocarbon selected galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Polycyclic aromatic hydrocarbon selected galaxies will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-386327