E. Zari, M. Lombardi, J. Alves, C.J. Lada, H. Bouy. 2016. Herschel-Planck dust optical depth and column density maps II. Perseus. Astronomy and Astrophysics 587, DOI: 10.1051/0004-6361/201526597
We present optical depth and temperature maps of the Perseus molecular cloud, obtained combining dust emission data from the Herschel and Planck satellites and 2MASS/NIR dust extinction maps. The maps have a resolution of 36 arcsec in the Herschel regions, and of 5 arcmin elsewhere. The dynamic range of the optical depth map ranges from 1 x 10(-2) mag up to 20 mag in the equivalent K-band extinction. We also evaluate the ratio between the 2.2 mu m extinction coefficient and the 850 mu m opacity. The value we obtain is close to the one found in the Orion B molecular cloud. We show that the cumulative and the differential area function of the data ( which is proportional to the probability distribution function of the cloud column density) follow power laws with an index of respectively similar or equal to-2, and similar or equal to-3. We use WISE data to improve current YSO catalogs based mostly on Spitzer data and we build an up-to-date selection of Class I/0 objects. Using this selection, we evaluate the local Schmidt law, Sigma(YSO) proportional to Sigma(beta)(gas), showing that beta = 2.4 +/- 0.6. Finally, we show that the area-extinction relation is important for determining the star-formation rate in the cloud, which is in agreement with other recent works.