J/ApJS/264/35 C18O dense cores in Orion A molecular cloud (Takemura+, 2023)
CARMA-NRO Orion survey: unbiased survey of dense cores and core mass functions
in Orion A.
Takemura H., Nakamura F., Arce H.G., Schneider N., Ossenkopf-Okada V.,
Kong S., Ishii S., Dobashi K., Shimoikura T., Sanhueza P., Tsukagoshi T.,
Padoan P., Klessen R.S., Goldsmith P.F., Burkhart B., Lis D.C.,
Sanchez-Monge A., Shimajiri Y., Kawabe R.
<Astrophys. J. Suppl. Ser., 264, 35 (2023)>
=2023ApJS..264...35T 2023ApJS..264...35T
ADC_Keywords: Carbon monoxide; Surveys; Molecular clouds; Interstellar medium;
YSOs; Space velocities; Stars, masses
Keywords: Star formation ; Interstellar medium ; Molecular clouds ;
Protostars
Abstract:
The mass distribution of dense cores is a potential key to
understanding the process of star formation. Applying dendrogram
analysis to the CARMA-NRO Orion C18O (J=1-0) data, we identify
2342 dense cores, about 22% of which have virial ratios smaller than
2 and can be classified as gravitationally bound cores. The derived
core mass function (CMF) for bound starless cores that are not
associate with protostars has a slope similar to Salpeter's initial
mass function (IMF) for the mass range above 1M☉, with a peak at
∼0.1M☉. We divide the cloud into four parts based on decl.,
OMC-1/2/3, OMC-4/5, L1641N/V380 Ori, and L1641C, and derive the CMFs
in these regions. We find that starless cores with masses greater than
10M☉ exist only in OMC-1/2/3, whereas the CMFs in OMC-4/5,
L1641N, and L1641C are truncated at around 5-10M☉. From the
number ratio of bound starless cores and Class II objects in each
subregion, the lifetime of bound starless cores is estimated to be
5-30 freefall times, consistent with previous studies for other
regions. In addition, we discuss core growth by mass accretion from
the surrounding cloud material to explain the coincidence of peak
masses between IMFs and CMFs. The mass accretion rate required for
doubling the core mass within a core lifetime is larger than that of
Bondi-Hoyle accretion by a factor of order 2. This implies that more
dynamical accretion processes are required to grow cores.
Description:
We obtained the data by combining the Combined Array for Research in
Millimeter-wave Astronomy (CARMA) interferometer and the Nobeyama
Radio Observatory (NRO) 45m single-dish telescope data as described in
the dense core survey in the Orion Nebula Cluster (ONC) region (Paper I;
Takemura+ 2021ApJ...910L...6T 2021ApJ...910L...6T). Details of the procedure are described
in detail in Kong+ (2018ApJS..236...25K 2018ApJS..236...25K). We used the C18O (J=1-0,
109.78218GHz) data, which cover the 1°x2° area of the Orion A
molecular cloud. The angular and velocity resolutions are the same as
in the previous map, corresponding to an angular resolution of 8" and
a velocity resolution of 0.1km/s. See Section 2.1.
In this paper, we estimate the core masses using the H2 column
density map. The H2 column density map was determined from
observations of the Herschel fluxes and is shown in Figure 1. Orion A
was observed in 2010 October within the Gould Belt key program
(Andre+ 2010A&A...518L.102A 2010A&A...518L.102A). See Section 2.2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table9.dat 114 2342 Physical properties of the starless C18O cores
in Orion A
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See also:
J/ApJ/428/693 : Rosette Nebula & Maddalena Cloud structures (Williams+ 1994)
J/ApJS/123/233 : Catalog of Optically selected cores (Lee+, 1999)
J/A+A/462/L17 : Dense cores in interstellar molecular clouds (Alves+, 2007)
J/ApJ/665/1194 : Dense cores in the Orion A cloud survey (Ikeda+, 2007)
J/MNRAS/374/1413 : SCUBA survey of Orion (Nutter+, 2007)
J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)
J/ApJ/748/14 : ONC population data from WFI observations (Da Rio+, 2012)
J/ApJ/764/114 : BVRI photometry of stars in Orion A (Hsu+, 2013)
J/A+A/564/A68 : Orion A GMC 13CO and C18O maps (Shimajiri+, 2014)
J/A+A/584/A91 : Dense cores in Aquila from Herschel (Konyves+, 2015)
J/ApJS/217/7 : Orion A dense cores based on 1.1mm & C18O (Shimajiri+, 2015)
J/ApJS/224/5 : Herschel Orion Protostar Survey (HOPS): SEDs (Furlan+, 2016)
J/A+A/587/A153 : VISION I. VISTA Orion A Survey (Meingast+, 2016)
J/A+A/604/A6 : SgrB2 ALMA continuum & spectral index (Sanchez-Monge+, 2017)
J/A+A/619/A106 : 3D shape of Orion A from Gaia DR2 (Grossschedl+, 2018)
J/A+A/610/A77 : Orion Integral Filament ALMA+IRAM30m N2H+ (Hacar+, 2018)
J/ApJ/862/105 : Core mass function across Gal. env. II. IRDCs (Liu+, 2018)
J/ApJ/886/102 : ALMA obs. of 70um dark high-mass clumps (Sanhueza+, 2019)
J/A+A/635/A2 : NGC6334 ALMA 87.6GHz cont. emission map (Sadaghiani+, 2020)
J/ApJ/912/156 : Core kinematics in the Dragon IRDC from ALMA (Kong+, 2021)
J/PASJ/73/487 : C18O cores in Orion A (Takemura+, 2021)
Byte-by-byte Description of file: table9.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Seq [1/2342] Internal index identifier
6 I1 h RAh [5] Hour of Right Ascension (J2000)
8- 9 I2 min RAm [37/42] Minute of Right Ascension (J2000)
11- 12 I2 s RAs Second of Right Ascension (J2000)
14 A1 --- DE- [-] Sign of the Declination (J2000)
15 I1 deg DEd [4/6] Degree of Declination (J2000)
17- 18 I2 arcmin DEm Arcminute of Declination (J2000)
20- 21 I2 arcsec DEs Arcsecond of Declination (J2000)
23- 27 F5.2 km/s VLSR [0.74/16.5] Local Standard of Rest velocity
29- 33 I5 arcsec2 Area [172/13228] Area, A
35- 39 F5.3 pc 2RCore [0.03/0.3] Core diameter
41- 44 F4.2 km/s FWHM [0.1/1.1] Full-Width at Half-Maximum
46- 50 F5.3 pc amaj [0.007/0.12] Semi-Major axis
52- 56 F5.3 pc bmin [0.004/0.051] Semi-Minor axis
58- 64 F7.2 deg PA [-180/180] Position angle
66- 70 F5.2 K TPeak [2.7/18.4] Peak temperature
72- 78 F7.1 K TTot [269.5/42895] Total temperature
80- 84 F5.2 Msun MCore [0/72.21] Core mass
86- 89 F4.2 Msun MVir [0/8.3] Virial mass
91- 95 F5.2 --- alpha [0/39.3] Virial ratio of a core
97-102 F6.2 10+4/cm-3 nCore [0/615.5] Core density
104 A1 --- St Starless core (1)
106-114 A9 --- Region Region identifier ("L1641C", "L1641N",
"OMC-1/2/3" or "OMC-4/5")
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Note (1): Flag as follows:
Y = starless core (2296 occurrences);
N = core is a protostellar core (46 occurrences).
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History:
From electronic version of the journal
References:
Takemura et al. Paper I. 2021ApJ...910L...6T 2021ApJ...910L...6T
Takemura et al. Paper II. 2021PASJ...73..487T 2021PASJ...73..487T Cat. J/PASJ/73/487
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 08-Mar-2023