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Abstract: A new, unbiased Spitzer-MIPS imaging survey ~1.8 square degs of the youngstellar content of the Vela Molecular Cloud-D is presented. The survey iscomplete down to 5mJy and 250mJy at 24micron mu and 70mu, respectively. 849sources are detected at 24mu and 52 of them also have a 70mu counterpart. TheVMR-D region is one that we have already partially mapped in dust and gasmillimeter emission, and we discuss the correlation between the Spitzer compactsources and the mm contours. About half of the 24mu sources are located insidethe region delimited by the 12CO1-0 contours corresponding to only one thirdof the full area mapped with MIPS with a consequent density increase of about100% of the 24mu sources four times for 70mu ones moving from outside toinside the CO contours. About 400 sources have a 2MASS counterpart. So we haveconstructed a Ks vs. Ks-24 diagram and identified the protostellarpopulation. We find an excess of Class I sources in VMR-D in comparison withother star forming regions. This result is reasonably biased by the sensitivitylimits, or, alternatively, may reflect a very short lifetime <=10^6yr of theprotostellar content in this cloud. The MIPS images have identified embeddedcool objects in most of the previously identified starless cores; in addition,there are 6 very young, possibly Class 0 objects identified. Finally we reportfinding of the driving sources for a set of five out of six very compactprotostellar jets previously discovered in near-infrared images.



Autor: T. Giannini 1, D. Lorenzetti 1, M. De Luca 1 and 2, B. Nisini 1, M. Marengo 3, L. Allen 3, H. A. Smith 3, G. Fazio 3, F. Massi 4,

Fuente: https://arxiv.org/







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