TY - JOUR

T1 - The Spitzer c2d survey of large, nearby, insterstellar clouds. II. Serpens observed with IRAC

AU - Harvey, Paul M.

AU - Chapman, Nicholas

AU - Lai, Shih Ping

AU - Evans, Neal J.

AU - Allen, Lori E.

AU - Jørgensen, Jes K.

AU - Mundy, Lee G.

AU - Huard, Tracy L.

AU - Porras, Alicia

AU - Cieza, Lucas

AU - Myers, Philip C.

AU - Merín, Bruno

AU - Van Dishoeck, Ewine F.

AU - Young, Kaisa E.

AU - Spiesman, William

AU - Blake, Geoffrey A.

AU - Koerner, David W.

AU - Padgett, Deborah L.

AU - Sargent, Anneila I.

AU - Stapelfeldt, Karl R.

PY - 2006/6/10

Y1 - 2006/6/10

N2 - We present maps of 0.89 deg2 of the Serpens dark cloud at 3.6, 4.5, 5.8, and 8.0 μm observed with the Spitzer Space Telescope Infrared Array Camera (IRAC). We discuss in detail the data processing carried out by the c2d team on IRAC data. More than 100,000 compact sources have been extracted, but we confine most of our discussion to the most reliable subset of these sources. This includes those that are detected above 7 σ in all four IRAC bands or those detected in the two shorter IRAC bands together with 2MASS. We estimate completeness limits for our survey from Monte Carlo tests with artificial sources inserted into the Spitzer maps. We compare source counts, colors, and magnitudes in the Serpens cloud to two reference data sets, a 0.10 deg2 set of low-extinction regions near the dark cloud and a 1 deg2 subset of the SWIRE Elais N1 data that was processed through our pipeline. We find that it is possible to identify more than 200 young stellar object (YSO) candidates from color-magnitude and color-color diagrams, most of which were previously unknown. In addition to the dense area of new star formation known before in the "core" region (cluster A), we also find a moderately rich area to the south (cluster B). Our mapped area also includes the Herbig Ae star VV Ser, whose Spitzer images have been carefully modeled in a separate study. The extreme sensitivity of Spitzer IRAC allows us to search to very low luminosity limits for young substellar objects. The comparison of the Serpens region with the reference areas suggests that a population of infrared excess sources exists in Serpens at least down to luminosities of L ∼ 10-3 L⊙ and possibly lower.

AB - We present maps of 0.89 deg2 of the Serpens dark cloud at 3.6, 4.5, 5.8, and 8.0 μm observed with the Spitzer Space Telescope Infrared Array Camera (IRAC). We discuss in detail the data processing carried out by the c2d team on IRAC data. More than 100,000 compact sources have been extracted, but we confine most of our discussion to the most reliable subset of these sources. This includes those that are detected above 7 σ in all four IRAC bands or those detected in the two shorter IRAC bands together with 2MASS. We estimate completeness limits for our survey from Monte Carlo tests with artificial sources inserted into the Spitzer maps. We compare source counts, colors, and magnitudes in the Serpens cloud to two reference data sets, a 0.10 deg2 set of low-extinction regions near the dark cloud and a 1 deg2 subset of the SWIRE Elais N1 data that was processed through our pipeline. We find that it is possible to identify more than 200 young stellar object (YSO) candidates from color-magnitude and color-color diagrams, most of which were previously unknown. In addition to the dense area of new star formation known before in the "core" region (cluster A), we also find a moderately rich area to the south (cluster B). Our mapped area also includes the Herbig Ae star VV Ser, whose Spitzer images have been carefully modeled in a separate study. The extreme sensitivity of Spitzer IRAC allows us to search to very low luminosity limits for young substellar objects. The comparison of the Serpens region with the reference areas suggests that a population of infrared excess sources exists in Serpens at least down to luminosities of L ∼ 10-3 L⊙ and possibly lower.

KW - Infrared: ISM

KW - ISM: clouds

UR - http://www.scopus.com/inward/record.url?scp=33747033110&partnerID=8YFLogxK

U2 - 10.1086/503520

DO - 10.1086/503520

M3 - Journal article

AN - SCOPUS:33747033110

VL - 644

SP - 307

EP - 325

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1

ER -