J/ApJ/786/37 The Auriga-California molecular cloud (Broekhoven-Fiene+, 2014)
The Spitzer survey of interstellar clouds in the Gould belt.
VI. The Auriga-California molecular cloud observed with IRAC and MIPS.
Broekhoven-Fiene H., Matthews B.C., Harvey P.M., Gutermuth R.A.,
Huard T.L., Tothill N.F.H., Nutter D., Bourke T.L., DiFrancesco J.,
Jorgensen J.K., Allen L.E., Chapman N.L., Cieza L.A., Dunham M.M.,
Merin B., Miller J.F., Terebey S., Peterson D.E., Stapelfeldt K.R.
<Astrophys. J., 786, 37 (2014)>
=2014ApJ...786...37B 2014ApJ...786...37B (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; YSOs ; Photometry, infrared ; Extinction
Keywords: infrared: general - ISM: clouds - stars: formation
Abstract:
We present observations of the Auriga-California Molecular Cloud (AMC)
at 3.6, 4.5, 5.8, 8.0, 24, 70, and 160 µm observed with the IRAC
and MIPS detectors as part of the Spitzer Gould Belt Legacy Survey.
The total mapped areas are 2.5 deg2 with IRAC and 10.47 deg2 with
MIPS. This giant molecular cloud is one of two in the nearby Gould
Belt of star-forming regions, the other being the Orion A Molecular
Cloud (OMC). We compare source counts, colors, and magnitudes in our
observed region to a subset of the SWIRE data that was processed
through our pipeline. Using color-magnitude and color-color diagrams,
we find evidence for a substantial population of 166 young stellar
objects (YSOs) in the cloud, many of which were previously unknown.
Most of this population is concentrated around the LkHα 101
cluster and the filament extending from it. We present a quantitative
description of the degree of clustering and discuss the relative
fraction of YSOs in earlier (Class I and F) and later (Class II)
classes compared to other clouds. We perform simple SED modeling of
the YSOs with disks to compare the mid-IR properties to disks in other
clouds and identify 14 classical transition disk candidates. Although
the AMC is similar in mass, size, and distance to the OMC, it is
forming about 15-20 times fewer stars.
Description:
We have mapped a significant fraction of the AMC with the Infrared
Array Camera (IRAC; Fazio et al. 2004ApJS..154...10F 2004ApJS..154...10F) and the
Mid-Infrared Photometer for Spitzer (MIPS; Rieke et al.
2004ApJS..154...25R 2004ApJS..154...25R) on board the Spitzer Space Telescope (Werner et al.
2004ApJS..154....1W 2004ApJS..154....1W), with a total overlapping coverage of 2.5 deg2 in
the four IRAC bands (3.6, 4.5, 5.8 and 8.0 um) and 10.47 deg2 in the
three MIPS bands (24, 70, and 160 um). The mapped areas are not all
contiguous and were chosen to include the areas with AV>3, as given
by the Dobashi et al. (2005PASJ...57....1S 2005PASJ...57....1S) extinction maps. The goal
of these observations is to identify and characterize the young stellar
object (YSO) and substellar object populations. The data presented
here are the first mid-IR census of the YSO population in this region.
Objects:
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RA (ICRS) DE Designation(s)
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04 10.0 +39 00 Auriga-California Molecular Cloud = NAME California MCld
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 186 138 YSOs in the AMC Based on IRAC and MIPS
table5.dat 186 28 YSO Candidates in the AMC Based on WISE and MIPS
table7.dat 37 91 SED modelling results in Class II sources
table8.dat 37 17 SED modelling results in Class III sources
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See also:
J/ApJ/680/495 : Survey of Interstellar clouds in the Gould belt
(Harvey+, 2008)
J/ApJS/185/198 : The Cepheus flare observed with IRAC and MIPS (Kirk+, 2009)
J/ApJS/194/43 : YSOs candidates and knots in CrA cloud (Peterson+, 2011)
J/ApJ/764/133 : Auriga-California giant molecular cloud (Harvey+, 2013)
J/ApJS/220/11 : SEDs of Spitzer YSOs in the Gould Belt (Dunham+, 2015)
Byte-by-byte Description of file: table4.dat table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- ID [1/166] YSO ID number
5- 20 A16 --- Name Name specifying J2000 coordinates
(HHMMSSss+DDMMSSs)
22- 24 A3 --- Class [I II III F] YSO SED Class
26- 30 F5.2 --- alpha Infrared spectral slope
32- 39 F8.3 mJy Flux3.6 ? Flux at IRAC1 3.6 micron band
41- 46 F6.3 mJy e_Flux3.6 ? Error in Flux3.6
48- 54 F7.2 mJy Flux4.5 ? Flux at IRAC2 4.5 micron band
56- 61 F6.2 mJy e_Flux4.5 ? Error in Flux4.5
63- 69 F7.2 mJy Flux5.8 ? Flux at IRAC3 5.8 micron band
71- 76 F6.2 mJy e_Flux5.8 ? Error in Flux5.8
78- 84 F7.2 mJy Flux8.0 ? Flux at IRAC4 8.0 micron band
86- 91 F6.2 mJy e_Flux8.0 ? Error in Flux8.0
93- 99 F7.2 mJy Flux3.4 ? Flux at WISE1 3.4 micron band
101-106 F6.2 mJy e_Flux3.4 ? Error in Flux3.4
108-114 F7.2 mJy Flux4.6 ? Flux at WISE2 4.6 micron band
116-121 F6.2 mJy e_Flux4.6 ? Error in Flux4.6
123-129 F7.2 mJy Flux12 ? Flux at WISE3 12 micron band
131-135 F5.2 mJy e_Flux12 ? Error in Flux12
137 A1 --- l_Flux12 [<] Limit flag on Flux12
138-143 F6.2 mJy Flux22 ? Flux at WISE4 22 micron band
145-149 F5.2 mJy e_Flux22 ? Error in Flux22
151 A1 --- l_Flux24 [<] Limit flag on Flux24
152-159 F8.2 mJy Flux24 ? Flux at MIPS1 24 micron band
161-167 F7.2 mJy e_Flux24 ? Error in Flux24
169-175 F7.1 mJy Flux70 ? Flux at MIPS2 70 micron band
177-184 F8.3 mJy e_Flux70 ? Error in Flux70
186 A1 --- lowNH2 [LN] Low column density flag (1)
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Note (1): Flag as follows:
L = The YSO is in a region of low column density, NH2<5x1021cm-2, and
so is a possible contaminant;
N = The YSO lies beyond the NH2 column density map from Harvey et al.
(2013, J/ApJ/764/133) and so NH2 at its position is unknown.
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Byte-by-byte Description of file: table7.dat table8.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- ID [2/166] YSO ID number
5- 6 A2 --- Fitted [K7-A0] Fitted stellar spectrum to the SED
8- 11 F4.1 mag Av Extinction value fitted to the optical data
13- 18 F6.2 Lsun L* Luminosity of the fitted stellar component
20- 23 F4.1 um lambda-TO Last wavelength before an excess >80%
is measured (1)
25- 28 F4.1 --- alpha-ex ? Slope of SED across wavelengths longward
of lambda-TO (2)
30- 37 F8.6 --- Ld/L* Ratio of disk luminosity to luminosity of
fitted stellar component
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Note (1): If no excess >80% is observed, then lambda-TO is set to 24 microns.
Note (2): No alpha-ex value is listed for sources with lambda-TO at 24 micron
because there are not enough data points to measure the slope of
the excess.
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History:
From electronic version of the journal
References:
Harvey et al. Paper I 2008ApJ...680..495H 2008ApJ...680..495H, Cat. J/ApJ/680/495
Kirk et al. Paper II 2009ApJS..185..198K 2009ApJS..185..198K, Cat. J/ApJS/185/198
Peterson et al. Paper III 2011ApJS..194...43P 2011ApJS..194...43P, Cat. J/ApJS/194/43
Spezzi et al. Paper IV 2011ApJ...730...65S 2011ApJ...730...65S
Hatchell et al. Paper V 2012ApJ...754..104H 2012ApJ...754..104H
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 16-Jun-2017