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111. CO obs. of molecular clouds in the MW midplane
ID:
ivo://CDS.VizieR/J/ApJS/254/3
Title:
CO obs. of molecular clouds in the MW midplane
Short Name:
J/ApJS/254/3
Date:
17 Jan 2022 11:34:49
Publisher:
CDS
Description:
In this work, we study the properties of molecular clouds in the second quadrant of the Milky Way Midplane, from l=104.75{deg} to l=119.75{deg}, and b=-5.25{deg} to b=5.25{deg}, using the ^12^CO, ^13^CO, and C^18^O J=1-0 emission line data from the Milky Way Imaging Scroll Painting project. We identify 857 and 300 clouds in the ^12^CO and ^13^CO spectral cubes, respectively, using the DENDROGRAM + SCIMES algorithms. The distances of the molecular clouds are estimated, and physical properties such as the mass, size, and surface densities of the clouds are tabulated. The molecular clouds in the Perseus Arm are about 30-50 times more massive, and 4-6 times larger than the clouds in the Local Arm. This result, however, is likely to be biased by distance selection effects. The surface densities of the clouds are enhanced in the Perseus Arm, with an average value of ~100M_{sun}_/pc^2^. Here. we select the 40 most extended (>0.35arcdeg^2^) molecular clouds from the ^12^CO catalog to build the H_2_ column density probability distribution function (N-PDF). Some 78% of the N-PDFs of the selected molecular clouds are well fitted with log-normal functions with only small deviations at high densities, corresponding to star-forming regions with scales of ~1-5pc in the Local Arm, and ~5-10pc in the Perseus Arm. About 18% of the selected molecular clouds have power-law N-PDFs at high densities. In these molecular clouds, the majority of the regions fitted with the power law correspond to molecular clumps at sizes of ~1pc, or filaments at widths of ~1pc.
112. CO obs. of molecular clouds in the 2nd quadrant
ID:
ivo://CDS.VizieR/J/ApJ/798/L27
Title:
CO obs. of molecular clouds in the 2nd quadrant
Short Name:
J/ApJ/798/L27
Date:
21 Oct 2021
Publisher:
CDS
Description:
Combining H I data from the Canadian Galactic Plane Survey and CO data from the Milky Way Imaging Scroll Painting project (MWISP), we have identified a new segment of a spiral arm between Galactocentric radii of 15 and 19kpc that apparently lies beyond the Outer Arm in the second Galactic quadrant. Over most of its length, the arm is 400-600pc thick in z. The new arm appears to be the extension of the distant arm recently discovered by Dame & Thaddeus (2011ApJ...734L..24D) as well as the Scutum-Centaurus Arm into the outer second quadrant. Our current survey identified a total of 72 molecular clouds with masses on the order of 10^2^-10^4^M_{sun}_ that probably lie in the new arm. When all of the available data from the CO molecular clouds are fit, the best-fitting spiral model gives a pitch angle of 9.3{deg}+/-0.7{deg}.
113. CO obs. of molecular outflows in the Cygnus complex
ID:
ivo://CDS.VizieR/J/ApJS/248/15
Title:
CO obs. of molecular outflows in the Cygnus complex
Short Name:
J/ApJS/248/15
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a survey of molecular outflows across the dark cloud complex in the Cygnus region, based on a 46.75deg^2^ field of CO isotopologue data from the Milky Way Imaging Scroll Painting (MWISP) survey. A supervised machine-learning algorithm, the support vector machine, is introduced to accelerate our visual assessment of outflow features in the data cube of ^12^CO and ^13^CO J=1-0 emission. A total of 130 outflow candidates are identified, 77 of which show bipolar structures and 118 are new detections. Spatially, these outflows are located inside dense molecular clouds, and some of them are found in clusters or in elongated linear structures tracing the underlying gas filament morphology. Along the line of sight, 97, 31, and 2 candidates reside in the Local, Perseus, and Outer Arms, respectively. Young stellar objects as outflow drivers are found near most outflows, while 36 candidates show no associated source. The clusters of outflows that we detect are inhomogeneous in their properties; nevertheless, we show that the outflows cannot inject turbulent energy on cloud scales. Instead, at best, they are restricted to affecting the so-called "clump" and "core" scales, and only on short (~0.3Myr) estimated timescales. Combined with outflow samples in the literature, our work shows a tight outflow mass-size correlation.
114. CO obs. of Planck Galactic cold clumps
ID:
ivo://CDS.VizieR/J/ApJS/247/29
Title:
CO obs. of Planck Galactic cold clumps
Short Name:
J/ApJS/247/29
Date:
21 Oct 2021
Publisher:
CDS
Description:
Sixty-five Planck Galactic cold clumps (PGCCs) from the first quadrant (IQuad) and 39 from the anticenter direction region (ACent) were observed in ^12^CO, ^13^CO, and C^18^O J=1-0 lines using the 13.7m telescope of the Purple Mountain Observatory. All the targets were detected in all three lines, except for 12 IQuad and 8 ACent PGCCs without C^18^O detection. Seventy-six and 49 velocity components were obtained in IQuad and ACent respectively; 146 cores were extracted from 76 IQuad clumps and 100 cores from 49 ACent clumps. The average Tex of IQuad cores and ACent cores is 12.4K and 12.1K, respectively. The average line widths of ^13^CO of IQuad cores and ACent cores are 1.55km/s and 1.77km/s, respectively. Among the detected cores, 24 in IQuad and 13 in ACent have asymmetric line profiles. The small blue excesses, ~0.03 in IQuad and 0.01 in ACent, indicate that star formation is not active in these PGCC cores. Power-law fittings of the core mass function to the high-mass end give indices of -0.57 in IQuad and -1.02 in ACent, which are flatter than the slope of the initial mass function given by Salpeter. The large turnover masses of 28M_{sun}_ for IQuad cores and 77M_{sun}_ for ACent cores suggest low star formation efficiencies in PGCCs. The correlation between virial mass and gas mass indicates that most PGCC cores in both regions are not likely pressure-confined.
115. CO obs. of the outer arm in the 2nd quadrant
ID:
ivo://CDS.VizieR/J/ApJS/224/7
Title:
CO obs. of the outer arm in the 2nd quadrant
Short Name:
J/ApJS/224/7
Date:
21 Oct 2021
Publisher:
CDS
Description:
The lack of arm tracers, especially remote tracers, is one of the most difficult problems preventing us from studying the structure of the Milky Way. Fortunately, with its high-sensitivity CO survey, the Milky Way Imaging Scroll Painting (MWISP) project offers such an opportunity. Since completing about one-third of its mission, an area of l=[100,150]{deg}, b=[-3,5]{deg} has nearly been covered. The Outer arm of the Milky Way first clearly revealed its shape in the second galactic quadrant in the form of molecular gas --this is the first time that the Outer arm has been reported in such a large-scale mapping of molecular gas. Using the 115GHz ^12^CO(1-0) data of MWISP at the LSR velocity ~[-100,-60]km/s and in the area mentioned above, we have detected 481 molecular clouds in total, and among them 332 (about 69%) are newly detected and 457 probably belong to the Outer arm. The total mass of the detected Outer arm clouds is ~3.1x10^6^M_{sun}__. Assuming that the spiral arm is a logarithmic spiral, the pitch angle is fitted as ~13.1{deg}. Besides combining both the CO data from MWISP and the 21cm HI data from the Canadian Galactic Plane Survey (CGPS), the gas distribution, warp, and thickness of the Outer arm are also studied.
116. Cool stars and brown dwarfs in Lupus clouds
ID:
ivo://CDS.VizieR/J/A+A/500/1045
Title:
Cool stars and brown dwarfs in Lupus clouds
Short Name:
J/A+A/500/1045
Date:
21 Oct 2021
Publisher:
CDS
Description:
Most studies of the stellar and substellar populations of star-forming regions rely on using the signatures of accretion, outflows, disks, or activity characterizing the early stages of stellar evolution. However, these signatures rapidly decay with time. We present the results of a wide-area study of the stellar population of clouds in the Lupus star-forming region. When combined with 2MASS photometry, our data allow us to fit the spectral energy distributions of over 150000 sources and identify possible new members based on their photospheric fluxes, independent of any display of the signposts of youth.
117. CO outflow cand. toward W3/4/5 complex. II.
ID:
ivo://CDS.VizieR/J/ApJS/251/26
Title:
CO outflow cand. toward W3/4/5 complex. II.
Short Name:
J/ApJS/251/26
Date:
21 Oct 2021
Publisher:
CDS
Description:
To date, few studies have focused on protostellar outflow feedback at scales larger than several parsecs. To address this paucity of research, we investigate the effects of feedback from CO outflow candidates on their parent clouds over ~110deg^2^ toward the W3/4/5 complex and its surroundings. Our search identified 265 ^13^CO clouds with radii being ~0.04-17.12pc. We estimate the turbulent support and potential disruptive effect of the outflow activities through analyzing physical properties of outflow candidates and their host clouds in terms of turbulence and gravitational binding energy. We find that (1) clouds of larger size might be less affected by feedback; (2) the possible scale break is >~4.7pc for both turbulent support and potential disruptive effect; (3) if outflows couple to dense gas where stars are forming, for clouds in the Perseus arm, a scale <~0.2-0.4pc is sufficient for the energy and momentum injected by outflow activity to maintain turbulence, while for clouds in the Local arm, the scale is <~0.1-0.2pc; and (4) for clouds in the Perseus arm, a scale <~0.3-1.0pc is needed for outflow activity to potentially disperse material away from the natal clouds, while for clouds in the Local arm, the scale is <~0.2-0.6pc. The strength of outflow activity may affect the values in points 3 and 4. Finally, we find that outflow feedback probably possesses the power to alter the line width-size relation.
118. Core mass function across Gal. env. II. IRDC clumps
ID:
ivo://CDS.VizieR/J/ApJ/862/105
Title:
Core mass function across Gal. env. II. IRDC clumps
Short Name:
J/ApJ/862/105
Date:
21 Oct 2021
Publisher:
CDS
Description:
We study the core mass function (CMF) within 32 dense clumps in seven infrared dark clouds (IRDCs) with the Atacama Large Millimeter/submillimeter Array via 1.3mm continuum emission at a resolution of ~1". We have identified 107 cores with the dendrogram algorithm, with a median radius of about 0.02pc. Their masses range from 0.261 to 178M_{sun}_. After applying completeness corrections, we fit the combined IRDC CMF with a power law of the form dN/d.logM{propto}M^-{alpha}^ and derive an index of {alpha}~0.86+/-0.11 for M>=0.79M_{sun}_ and {alpha}~0.70+/-0.13 for M>=1.26M_{sun}_, which is a significantly more top-heavy distribution than the Salpeter stellar initial mass function index of 1.35. We also make a direct comparison of these IRDC clump CMF results to those measured in the more evolved protocluster G286 derived with similar methods, which have {alpha}~1.29+/-0.19 and 1.08+/-0.27 in these mass ranges, respectively. These results provide a hint that, especially for the M>=1.26M_{sun}_ range where completeness corrections are modest, the CMF in high pressure, early-stage environments of IRDC clumps may be top-heavy compared to that in the more evolved, global environment of the G286 protoclusters. However, larger samples of cores probing these different environments are needed to better establish the robustness of this potential CMF variation.
119. Cores in California molecular cloud
ID:
ivo://CDS.VizieR/J/A+A/620/A163
Title:
Cores in California molecular cloud
Short Name:
J/A+A/620/A163
Date:
21 Oct 2021
Publisher:
CDS
Description:
We extracted 300 cores, of which 33 are protostellar and 267 are starless cores. About 51% (137 of 267) of the starless cores are prestellar cores. Three cores have the potential to evolve into high-mass stars. The prestellar core mass function (CMF) can be well fit by a log-normal form. The high-mass end of the prestellar CMF shows a power-law form with an index {alpha}=-0.9+/-0.1 that is shallower than that of the Galactic field stellar mass function. Combining the mass transformation efficiency ({epsilon}) from the prestellar core to the star of 15+/-1% and the core formation efficiency (CFE) of 5.5%, we suggest an overall star formation efficiency of about 1% in the CMC. In the single-pointing observations with the IRAM 30m telescope, we find that 6 cores show blue-skewed profile, while 4 cores show red-skewed profile. [HCO^+^]/[HNC] and [HCO^+^]/[N_2_H^+^] in protostellar cores are higher than those in prestellar cores; this can be used as chemical clocks. The best-fit chemical age of the cores with line observations is ~50000 years.
120. Cores in IR Dark Clouds for 300<=l<=330
ID:
ivo://CDS.VizieR/J/MNRAS/422/1071
Title:
Cores in IR Dark Clouds for 300<=l<=330
Short Name:
J/MNRAS/422/1071
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have used data taken as part of the Herschel infrared Galactic Plane survey (Hi-GAL) to study 3171 infrared dark cloud (IRDC) candidates that were identified in the mid-IR (8um) by Spitzer (we refer to these as 'Spitzer-dark' regions). They all lie in the range l=300-330{deg} and |b|<=1{deg}. Of these, only 1205 were seen in emission in the far-IR (250-500um) by Herschel (we call these 'Herschel-bright' clouds). It is predicted that a dense cloud will not only be seen in absorption in the mid-IR, but will also be seen in emission in the far-IR at the longest Herschel wavebands (250-500um). If a region is dark at all wavelengths throughout the mid-IR and far-IR, then it is most likely to be simply a region of lower background IR emission (a 'hole in the sky'). Hence, it appears that previous surveys, based on Spitzer and other mid-IR data alone, may have overestimated the total IRDC population by a factor of ~2. This has implications for estimates of the star formation rate in IRDCs in the Galaxy. We studied the 1205 Herschel-bright IRDCs at 250um and found that 972 of them had at least one clearly defined 250-um peak, indicating that they contained one or more dense cores. Of these, 653 (67 per cent) contained an 8-um point source somewhere within the cloud, 149 (15 per cent) contained a 24-um point source but no 8-um source and 170 (18 per cent) contained no 24- or 8-um point sources. We use these statistics to make inferences about the lifetimes of the various evolutionary stages of IRDCs.

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