J/ApJ/921/23 C18O dense cores identified in the CMC region (Guo+, 2021)
A wide-field CO survey toward the California molecular filament.
Guo W., Chen X., Feng J., Sun Li, Wang C., Su Y., Sun Y., Ao Y., Zhang S.,
Zhou X., Yuan L., Yang Ji
<Astrophys. J., 921, 23 (2021)>
=2021ApJ...921...23G 2021ApJ...921...23G
ADC_Keywords: Interstellar medium; Carbon monoxide; Surveys; Molecular clouds;
Space velocities; YSOs
Keywords: Interstellar medium ; Interstellar filaments ;
Giant molecular clouds ; Star formation
Abstract:
We present the survey of 12CO/13CO/C18O (J=1-0) toward the
California molecular cloud (CMC) within the region of
161.75°≤l≤167.75°, -9.5°≤b≤-7.5° using the Purple
Mountain Observatory (PMO) 13.7m millimeter telescope. Adopting a
distance of 470pc, the mass of the observed molecular cloud estimated
from 12CO, 13CO, and C18O is about 2.59x104, 0.85x104, and
0.09x104M☉, respectively. A large-scale continuous filament
extending about 72pc is revealed from the 13CO images. A systematic
velocity gradient perpendicular to the major axis appears and is
measured to be ∼0.82km/s/pc. The kinematics along the filament shows
an oscillation pattern with a fragmentation wavelength of ∼2.3pc and
velocity amplitude of ∼0.92km/s, which may be related to core-forming
flows. Furthermore, assuming an inclination angle to the plane of the
sky of 45°, the estimated average accretion rate is
∼101M☉/Myr for the cluster LkHα 101 and ∼21M☉/Myr
for the other regions. In the C18O observations, the large-scale
filament could be resolved into multiple substructures, and their
dynamics are consistent with the scenario of filament formation from
converging flows. Approximately 225 C18O cores are extracted, of
which 181 are starless cores. Roughly 37% (67/181) of the starless
cores have αvir less than 1. Twenty outflow candidates are
identified along the filament. Our results indicate active early-phase
star formation along the large-scale filament in the CMC region.
Description:
The Milky Way Imaging Scroll Painting (MWISP) project is a large
CO(J=1-0) multiline survey toward the northern Galactic plane using
the Purple Mountain Observatory (PMO) 13.7m millimeter telescope.
As a part of the MWISP survey, we present in this work the results of
the three CO (J=1-0) isotopologue line observations toward the
California molecular cloud (CMC).
The three CO isotopologue line observations were simultaneously
performed from 2012 February to 2014 May with the PMO 13.7m millimeter
telescope located in Delingha, China.
The frequency of the local oscillator was carefully selected; thus,
12CO (115.271GHz) is at the upper sideband, and 13CO (110.201GHz)
and C18O (109.782GHz) are at the lower sideband.
We identify a total of 225 C18O dense cores with a mean size of
0.12pc and a mean mass of 3.3M☉ in the CMC region. Of the 225
dense cores, 181 are found to have no association with YSOs.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 88 225 Properties of the identified dense cores
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See also:
II/197 : ISM towards IC 348 and Per OB2 (Cernis, 1993)
J/A+A/487/993 : MAMBO Mapping of c2d Clouds and Cores (Kauffmann+, 2008)
J/ApJ/699/1092 : Giant molecular clouds (SRBY) (Heyer+, 2009)
J/ApJ/715/671 : X-ray and IR emission from YSOs (Wolk+, 2010)
J/A+A/554/A55 : C18O(1-0) and N2H+(1-0) in L1495/B213 (Hacar+, 2013)
J/ApJ/764/133 : Auriga-California giant molecular cloud (Harvey+, 2013)
J/ApJ/767/36 : APEX observations of HOPS protostars (Stutz+, 2013)
J/ApJ/786/37 : Auriga-California molecular cloud (Broekhoven-Fiene+, 2014)
J/A+A/588/A104 : Molecular clouds and star formation (Gong+, 2016)
J/A+A/606/A100 : YSOs in California Molecular Cloud (Lada+, 2017)
J/ApJ/838/49 : CO large-field observations around l=150° (Xiong , 2017)
J/A+A/616/A78 : Dust extinction map of the Nessie filament (Mattern+, 2018)
J/A+A/620/A163 : Cores in California molecular cloud (Zhang+, 2018)
J/A+A/642/A76 : California molecular cloud CO datacubes (Zhang+, 2020)
http://www.radioast.nsdc.cn/mwisp.php : MWISP home page
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- --- [MWISP]
7- 20 A14 --- MWISP Core position-based name (GLLL.lll+B.bbb)
22- 25 F4.2 arcmin amaj [0.97/6.8] Angular size, major axis
27- 30 F4.2 arcmin bmin [0.98/5.4] Angular size, minor axis
32- 37 F6.2 deg PA [-85.6/177.4] Position Angle
39- 43 F5.2 km/s Vlsr [-3.31/0.52] Velocity relative to LSR
45- 48 F4.2 km/s DV [0.17/0.71] Line FWHM
50- 53 F4.2 pc Reff [0.02/0.28] Effective (deconvolved) radius
55- 59 F5.2 K Tex [6.17/33.15] Excitation temperature
61- 65 F5.2 10+21cm-2 NH2 [0.56/14.03] Column density, H2
67- 72 F6.2 10+3cm-3 nH2 [2.15/294.71] Volume number density, H2
74- 77 F4.1 Msun MLTE [0.7/53.1] LTE Mass
79- 83 F5.2 Msun Mvir [0.61/22.21] Virial Mass
85- 88 F4.2 --- aVir [0.3/2.49] Virial α parameter, Mvir/MLTE
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 03-Feb-2023