J/AJ/150/95 Masses and ages of YSOs in Per OB2 (Azimlu+, 2015)
A WISE census of young stellar objects in the Perseus OB2 association.
Azimlu M., Martinez-Galarza J.R., Muench A.A.
<Astron. J., 150, 95 (2015)>
=2015AJ....150...95A 2015AJ....150...95A (SIMBAD/NED BibCode)
ADC_Keywords: Associations, stellar ; Stars, pre-main sequence ; YSOs ;
Stars, masses ; Stars, ages
Keywords: infrared: stars - stars: formation - stars: pre-main sequence -
stars: protostars
Abstract:
We have performed a Wide-Field Infrared Survey Explorer based study to
identify and characterize young stellar objects (YSOs) in the
12°x12° Perseus OB2 association. A spectral energy
distribution (SED) slope in the range of 3.4-12µm and 5σ
selection criteria were used to select our initial sample. Further
manual inspection reduced our final catalog to 156 known and 119 YSO
candidates. The spatial distribution of newly found YSOs all over the
field shows an older generation of star formation in which most of its
massive members have evolved into main-sequence stars. In contrast,
the majority of younger members lie within the Perseus molecular cloud
and currently active star-forming clusters such as NGC 1333 and IC
348. We also identified an additional 66 point sources that passed YSO
selection criteria but are likely AGB stars. However, their spatial
distribution suggests that they may contain a fraction of the YSOs.
Comparing our results with the commonly used color-color selections,
we found that while the color selection method fails in picking up
bright but evolved weak disks, our SED fitting method can identify
such sources, including transitional disks. In addition, we have less
contamination with background sources such as galaxies, but at a price
of losing fainter (Jmag>12) YSOs. Finally, we employed a Bayesian
Monte Carlo SED fitting method to determine the characteristics of
each YSO candidate. Distribution of SED slopes and model-driven age
and mass confirms separated YSO populations with three suggested age
groups of younger than 1Myr old, 1-5Myr old, and older than 5Myr,
which agrees with the age of the Per OB2 association and currently
star-forming sites within the cloud.
Description:
We have performed a Wide-field Infrared Survey Explorer (WISE) based
study to identify and characterize young stellar objects (YSOs) in the
12°*12° Perseus OB2 association. A spectral energy
distribution (SED) slope in the range of 3.4-12µm and 5σ
selection criteria were used to select our initial sample. Further
manual inspection reduced our final catalog to 156 known (see Table3)
and 119 (see Table2) new YSO candidates. We also identified an
additional 66 point sources (see Table 4) that passed YSO selection
criteria but are likely AGB stars. However, their spatial distribution
suggests that they may contain a fraction of the YSOs.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 118 119 Physical parameters measured for the 119 new
candidates
table3.dat 118 156 Physical parameters measured for the 156 known
candidates
table4.dat 118 66 Physical parameters measured for the 66 AGB
candidates
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See also:
II/311 : WISE All-Sky Data Release (Cutri+ 2012)
I/317 : The PPMXL Catalog (Roeser+ 2010)
J/ApJ/692/973 : Protostars in Perseus, Serpens and Ophiuchus (Enoch+, 2009)
J/ApJS/175/509 : Ammonia spectral atlas in Perseus (Rosolowsky+, 2008)
J/AJ/134/411 : Properties of IC 348 members (Muench+, 2007)
J/AJ/131/1574 : Infrared photometry of IC348 members (Lada+, 2006)
J/ApJ/646/1009 : Structures of dust in Perseus molecular cloud (Kirk+, 2006)
J/A+A/384/145 : Catalog of Per OB2 star forming complex (Belikov+, 2002)
J/ApJ/497/736 : The young cluster IC 348. (Herbig, 1998)
Byte-by-byte Description of file: table[234].dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/156] Internal sequential number
5- 23 A19 --- Name Catalog identifier (JHHMMSS.ss+DDMMSS.s)
25- 34 F10.7 deg RAdeg Right Ascension in decimal degrees (J2000)
36- 45 F10.7 deg DEdeg Declination in decimal degrees (J2000)
47- 75 A29 --- OName Other source identifier
77- 81 F5.2 --- alpha [-2.67/2.62] WISE 3-12µm spectral index
83- 86 F4.2 --- e_alpha [0.02/0.53] Uncertainty in alpha
88- 92 F5.2 Msun MassBF [0.1/17.26] Best fit model mass (1)
94- 98 F5.2 Msun Mpeak [0.11/25.69] Peak model mass (2)
100-103 F4.2 Msun e_Mpeak ? Uncertainty in MPeak
105-108 F4.2 Myr AgeBF [0/9.89] Best fit model age (1)
110-113 F4.2 Myr Apeak [0/9.6] Peak model age (2)
115-118 F4.2 Myr e_Apeak ? Uncertainty in APeak
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Note (1): The model that minimizes the χ2.
Note (2): The model that maximizes the probability distribution functions.
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 21-Oct-2015