J/ApJS/261/13 High-velocity dispersion compact clouds in the CMZ (Oka+, 2022)
Catalog of high-velocity dispersion compact clouds in the central molecular zone
of our galaxy.
Oka T., Uruno A., Enokiya R., Nakamura T., Yamasaki Y., Watanabe Y.,
Tokuyama S., Iwata Y.
<Astrophys. J. Suppl. Ser., 261, 13 (2022)>
=2022ApJS..261...13O 2022ApJS..261...13O
ADC_Keywords: Molecular clouds; Galactic center; Velocity dispersion;
Carbon monoxide
Keywords: Galactic center
Abstract:
This study developed an automated identification procedure for compact
clouds with broad velocity widths in the spectral-line data cubes of
highly crowded regions. The procedure was applied to the CO J=3-2 line
data, obtained using the James Clerk Maxwell Telescope, to identify
184 high-velocity dispersion compact clouds (HVDCCs), which are a
category of peculiar molecular clouds found in the central molecular
zone of our Galaxy. A list of HVDCCs in the area -1.4°≤l≤+2.0°,
-0.25°≤b≤+0.25° was presented with their physical parameters,
CO J=3-2/J=1-0 intensity ratios, and morphological classifications.
Consequently, the list provides several intriguing sources that may
have been driven by encounters with pointlike massive objects, local
energetic events, or cloud-to-cloud collisions.
Description:
To identify high-velocity dispersion compact clouds (HVDCCs) in the
central molecular zone (CMZ), the CO J=3-2 (345.796GHz) line data
obtained using the James Clerk Maxwell Telescope (JCMT) by the JCMT
Galactic plane survey (JPS) team (Parsons+ 2018, J/ApJS/234/22) was
utilized. The observations were conducted in the periods ranging from
2013 July-September, in 2014 July, and from 2015 March to June.
The Hetrodyne Array Receiver Program was employed to obtain the
CO J=3-2 image of the CMZ. In addition, the autocorrelation spectral
imaging system (ACSIS) was also employed as a receiver backend with
the 1800MHz bandwidth and 0.97MHz spectral resolution mode.
The CO J=1-0 (115.271GHz) line data, used to calculate the CO J=1-0
luminosity and CO J=3-2/J=1-0 intensity ratio (R3-2/1-0), was obtained
from observations using the 45m telescope at the Nobeyama Radio
Observatory (NRO) in 2011 January.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 74 184 Catalog of high-velocity dispersion compact clouds
(HVDCCs)
table5.dat 53 184 Physical parameters of high-velocity dispersion
compact clouds (see Appendix A)
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See also:
J/A+A/391/159 : A search for Compact High-Velocity Clouds (De Heij+, 2002)
J/AJ/123/873 : HIPASS high-velocity clouds (Putman+, 2002)
J/ApJ/623/181 : Compact high-velocity cloud photometry catalog (Siegel+, 2005)
J/ApJ/768/77 : Ultra-compact high velocity clouds from ALFALFA (Adams+, 2013)
J/ApJ/806/95 : A search for ultra-compact HVC counterparts (Sand+, 2015)
J/ApJS/234/22 : SCUBA-2 Galactic Center compact source catalog (Parsons+, 2018)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/184] Running sequence number
5- 10 F6.3 deg GLON [-1.41/1.8] Galactic longitude
12- 17 F6.3 deg GLAT [-0.25/0.25] Galactic latitude
19- 24 F6.1 km/s Vlsr [-207.4/184.6] Local Standard of Rest velocity
26- 32 A7 --- Morph1 Morphological type, primary class, Type 1 (1)
34- 40 A7 --- Morph2 Morphological type, secondary class, Type 2
42- 68 A27 --- pID Previous identification(s) (see Section 4.1)
70- 74 A5 --- Ref Reference(s) (2)
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Note (1): Morphological type (see Section 4.2) as follows:
complex = few components with complex morphologies and/or kinematics
(46 occurrences)
simple = generally isolated in the l-b-V space, which has simple kinematics
(35 occurrences)
bridge = This type of high-velocity dispersion compact clouds (HVDCC)
connects two molecular clouds with different velocities in the
position-velocity space (18 occurrences)
shell = shell-/arc-shaped morphology and expanding kinematics, suggesting
an origin related to local explosive events (28 occurrences)
wing = a compact broad-velocity-width emission arises from a parent
normal-velocity-width cloud in position-velocity maps
(57 occurrences)
Note (2): Reference as follows:
a = Nagai M. 2008, PhD thesis The Univ. of Tokyo
b = Oka et al. (1999ApJ...515..249O 1999ApJ...515..249O)
c = Oka et al. (2001PASJ...53..787O 2001PASJ...53..787O)
d = Oka et al. (2008PASJ...60..429O 2008PASJ...60..429O)
e = Oka et al. (2011ApJ...732..120O 2011ApJ...732..120O)
f = Oka et al. (2012ApJS..201...14O 2012ApJS..201...14O)
g = Oka et al. (2016ApJ...816L...7O 2016ApJ...816L...7O)
h = Matsumura et al. (2012ApJ...756...87M 2012ApJ...756...87M)
i = Tsujimoto et al. (2018ApJ...856...91T 2018ApJ...856...91T)
j = Tsujimoto et al. (2021ApJ...910...61T 2021ApJ...910...61T)
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/184] Running sequence number
5- 8 F4.2 pc Size [0.23/6] Size, S (3)
10- 13 F4.1 km/s Sigma [20/61.6] Velocity dispersion, σV
15- 18 F4.1 10+2K.km.s-1.pc2 LCO [0.6/58.3] CO J=3-2 luminosity
20- 24 F5.1 10+2Msun MCO [1.8/178.3] Molecular gas mass
26- 30 F5.1 10+5Msun MVT [2.5/206.8] Virial theorem mass, MVT
32- 37 F6.1 10+41J Ekin [3.1/1064.9] Kinetic energy in 1048erg
39- 42 F4.1 10+4yr Texp [0.9/28] Expansion time
44- 48 F5.1 10+29W Pkin [4/751.1] Kinetic power in 1036erg/s
50- 53 F4.2 --- RCO [0.66/2.2]? CO J=3-2/J=1-0 intensity
ratio, R3-2/1-0
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Note (3): The size of the cloud can be calculated using the following formula:
Equation (A1): S=D.tan(σlσb)0.5
where σx is the dispersion in the x-direction, and
D represents the distance to the cloud. In addition, D=DGC was
employed here.
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 22-Sep-2022