Revisiting the Protostellar Phase Lifetime with SESNA, the Spitzer Extended Solar Neighborhood Archive
Abstract
Spitzer-based surveys of star-forming clouds were a revolutionary step forward in their simultaneous extremely wide coverage and excellent mass completeness to dusty young stellar objects (YSOs). However, many of these surveys were analyzed by independent groups that emphasized differing primary science goals, thus even trivial analyses demonstrate clear discrepancies when compared. These issues can usually be traced back to qualitative differences in data treatment trade-offs, but progress beyond that is stymied without a more complete solution. Our solution is SESNA, a collection of uniformly produced Spitzer mosaics, source catalogs, and YSO identifications, all backed by complementary completeness mapping products, for most of the star-forming clouds within the nearest 1.5 kpc surveyed during the Spitzer cryogen mission. The collection includes most of the clouds closer than 500 pc in Gould's Belt, Cygnus-X at 1.4 kpc, and many other clouds at distances between those extremes. The full archive spans 92 sq. deg. (plus another 16 sq. deg. of extragalactic fields to explore residual contamination rates), and the catalog contains over ten million sources with tens of thousands of YSOs identified consistently across all surveys. Here we introduce SESNA and demonstrate its utility as a more precise and more powerful means to perform fundamental characterizations in star formation by way of the nominally simple example of constraining the protostellar phase lifetime. Specifically, we utilize the SESNA catalog and completeness maps to extract an extremely uniformly observed subset of YSOs, and then further constrain the sample based on relative surface densities of stars and gas at parsec scales to limit evolutionary differences across regions. The final subsample enables greater statistical leverage than has been achieved to date for constraining the protostellar phase lifetime. This research is supported by NASA ADAP NNX17AF24G.
- Publication:
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American Astronomical Society Meeting Abstracts #233
- Pub Date:
- January 2019
- Bibcode:
- 2019AAS...23336710G