INFRARED SPECTRAL PROPERTIES OF WOLF-RAYET GALAXIES

We present infrared properties of 22 WR galaxies having optical classifications as Starburst Galaxies and having Spitzer IRS mid-infrared spectra available from CASSIS. To understand infrared properties of these galaxies we have compared our sample with two independent ultraviolet-selected starburst galaxy samples. We have compared the hardness of radiation of these three samples, using the ratio of total fluxes of [NeIII] 15.55 mu m and PAH 11.3 mu m, which shows a presence of younger stars in WR galaxies, compared to other UV samples. We also have calibrated the IR and UV SFRs. Our results show that the similar to 35% of the UV luminosity of WR SB galaxies is observed, compared to similar to 9% and similar to 25% of other UV samples. We determine that the classification of objects to pure SB based on criteria EW(6.2 mu m)>0.4 mu m is not applicable for SB galaxies with the youngest star populations.