Distances to molecular clouds in the second Galactic quadrant

Yan, Qing-Zeng; Yang, Ji; Sun, Yueqiang; Su, Yang; Xu, Ye; Wang, Hongchi; Zhou, Xin; Wang, Chen

doi:10.1051/0004-6361/202039768

Cited by 18 publications

(29 citation statements)

References 38 publications

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“…With the same method, Yan et al (2020) determined the distances for 28 local molecular clouds (d < 1.5 kpc, here d is the distance to the Sun) in the first Galactic quadrant. The distances for 76 molecular clouds were measured in the second Galactic quadrant by Yan et al (2021). Based on a sample of over 32 million stars with color excesses and Gaia distances, Chen et al (2019b) constructed new three-dimensional dust reddening maps of the Milky Way.…”

Section: Giant Molecular Cloudsmentioning

confidence: 99%

The Spiral Structure in the Solar Neighborhood

Hou

2021

Front. Astron. Space Sci.

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The spiral structure in the solar neighborhood is an important issue in astronomy. In the past few years, there has been significant progress in observation. The distances for a large number of good spiral tracers, i.e., giant molecular clouds, high-mass star-formation region masers, HII regions, O-type stars, and young open clusters, have been accurately estimated, making it possible to depict the detailed properties of nearby spiral arms. In this work, we first give an overview about the research status for the Galaxy’s spiral structure based on different types of tracers. Then the objects with distance uncertainties better than 15% and <0.5 kpc are collected and combined together to depict the spiral structure in the solar neighborhood. Five segments related with the Perseus, Local, Sagittarius-Carina, Scutum-Centaurus, and Norma arms are traced. With the large dataset, the parameters of the nearby arm segments are fitted and updated. Besides the dominant spiral arms, some substructures probably related to arm spurs or feathers are also noticed and discussed.

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Section: Giant Molecular Cloudsmentioning

confidence: 99%

The Spiral Structure in the Solar Neighborhood

Hou

2021

Front. Astron. Space Sci.

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“…The extracting method we used was developed by Yan et al (2020), based on the Density-Based Spatial Clustering of Applications with Noise (DBSCAN) algorithm, which was originally designed to discover clusters of arbitrary shape (Ester et al 1996). Yan et al (2021a) has completed the identification of molecular clouds using the DBSCAN algorithm in the second Galactic quadrant with 104.75 • < l < 150.25 • , |b| < 5.25 • , and −95 km s −1 < V LSR < 25 km s −1 . We check the averaged 12 CO(1-0) line profile and the velocity-integrated intensity map for each cloud, 18190 out of 18503 molecular clouds can be used for further analysis.…”

Section: An Unbiased Catalog Of Molecular Cloudsmentioning

confidence: 99%

“…The typical range of each parameter, which is from the quantile of 0.25 to 0.75 in its sequential data, has been listed in Table 2. Although Yan et al (2021a) has calculated the dis-tance of 76 molecular clouds in this catalog, most of the molecular clouds in this catalog do not have the available distance information. Thus, we group the 18190 molecular clouds into two parts, corresponding to the near and far ranges, respectively.…”

Section: An Unbiased Catalog Of Molecular Cloudsmentioning

confidence: 99%

“…In this paper, we focus on the unbiased catalog of molecular clouds in the Galactic plane with 104.75 • < l < 150.25 • , −5.25 • < b < 5.25 • , and −95 km s −1 < V LSR < 25 km s −1 provided by the MWISP (Yan et al 2021a). This catalog consists of 18190 molecular clouds.…”

Section: Introductionmentioning

confidence: 99%

“…Also, the well-known molecular clouds located within the map-regions have been noted. Parts of the observations in this region previously were published in Yan et al (2021a); Sun et al (2020); Du et al (2016Du et al ( , 2017.…”

Section: Introductionmentioning

confidence: 99%

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A Morphological Classification of 18190 Molecular Clouds Identified in $^{12}$CO Data from the MWISP Survey

Yuan,

Yang,

et al. 2021

Preprint

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We attempt to visually classify the morphologies of 18190 molecular clouds, which are identified in the 12 CO(1-0) spectral line data over ∼ 450 deg 2 of the second Galactic quadrant from the Milky Way Imaging Scroll Painting project (MWISP). Using the velocity-integrated intensity maps of the 12 CO(1-0) emission, molecular clouds are first divided into unresolved and resolved ones. The resolved clouds are further classified as non-filaments or filaments. Among the 18190 molecular clouds, ∼ 25 % are unresolved, ∼ 64% are non-filaments, and ∼ 11% are filaments. In the terms of the integrated flux of 12 CO(1-0) spectra of the whole 18190 molecular clouds, ∼ 90% are from filaments, ∼ 9% are from non-filaments, and the rest ∼ 1% are from unresolved sources. Although non-filaments are dominant in the number of the discrete molecular clouds, filaments are the main contributor of 12 CO emission flux. We also present the number distributions of physical parameters of the molecular clouds in our catalog, including their angular sizes, velocity spans, peak intensities of 12 CO(1-0) emission, and 12 CO(1-0) total fluxes. We find that there is a systematic difference between the angular sizes of the non-filaments and filaments, with the filaments tending to have larger angular scales. The H 2 column densities of them are not significantly different. We also discuss the observational effects, such as those induced by the finite spatial resolution, beam dilution and line-of-sight projection, on the morphological classification of molecular clouds in our sample.

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Large-field CO (J= 1−0) observations toward SNR G150.3+4.5

Feng,

Chen,

et al. 2024

A&A

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We aim to investigate the molecular environment of the supernova remnant (SNR) G150.3+4.5, and explore its association with ambient molecular clouds (MCs). We present large-field CO (J=1-0) molecular line observations toward SNR G150.3+4.5, using the 13.7 m millimeter telescope of the Purple Mountain Observatory. The observations have an angular resolution of $ 55 ''$. We analyzed the spatial distribution of MCs in relation to the SNR shell detected in previous Urumqi lambda 6 cm radio observations and examined the CO spectra for kinematics information. We find that MCs within the velocity range of km s$^ $ are spatially distributed along the radio shell of the SNR. Line broadening and asymmetries are observed in the CO spectra of the clouds. Moreover, we find that the molecular clouds around the shell have systematic velocity gradients in the position--velocity (PV) diagram. Both the morphology alignment and gas kinematics suggest that the SNR is associated with the ambient MCs at sim 740 pc. Based on the CO gas distance, the dimension and the age of the SNR are estimated to be 40 pc times 33 pc and 3.8 $ 10^4$ years, respectively. The very high energy emission of 1LHAASO J0428+5531 toward the SNR may originate from the interaction between the SNR and the surrounding MCs.

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Distances to molecular clouds in the second Galactic quadrant

Cited by 18 publications

References 38 publications

The Spiral Structure in the Solar Neighborhood

The Spiral Structure in the Solar Neighborhood

A Morphological Classification of 18190 Molecular Clouds Identified in $^{12}$CO Data from the MWISP Survey

Large-field CO (J= 1−0) observations toward SNR G150.3+4.5

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