相关论文: Rethinking a Mysterious Molecular Cloud
The dwarf elliptical galaxy NGC 185- the closest early-type galaxy with detectable molecular gas- offers a unique opportunity for high angular resolution studies of the interstellar medium in early-type galaxies. I present interferometric…
We study the relationship between molecular gas and dust in the California Molecular Cloud over an unprecedented dynamic range of cloud depth (Av = 3 - 60 magnitudes). We compare deep Herschel-based measurements of dust extinction with…
(abridged) We report a study of the relation between dust and gas over a 100deg^2 area in the Taurus molecular cloud. We compare the H2 column density derived from dust extinction with the CO column density derived from the 12CO and 13CO J=…
We investigate how the X factor, the ratio of H_2 column density (NH2) to velocity-integrated CO intensity (W), is determined by the physical properties of gas in model molecular clouds (MCs). We perform radiative transfer calculations on…
Three molecular clouds have been mapped in the nearby metal-poor dwarf irregular galaxy NGC 6822 using the Owens Valley Millimeter-Wave Interferometer. Based on upper limits to the virial masses of the clouds, the CO-to-H2 conversion factor…
The general lack of molecular oxygen in molecular clouds is an outstanding problem in astrochemistry. Extensive searches with SWAS, Odin and Herschel have only produced two detections; upper limits to the O_2 abundance in the remaining…
We made CO(1-0) observations of 103 lines of sight in the core and envelope of the high-latitude cloud MBM 40 to determine how the CO-H_2 conversion factor (X_CO) varies throughout the cloud. Calibrating X_CO with CH data at similar…
The outer Galaxy presents an optimal setting for investigating molecular clouds and star formation in environments with low metallicity. A total of 72 Galactic edge clouds were surveyed using the CO\,(2--1) line with the IRAM\,30\,m…
We present the ALMA survey of CO(2-1) emission from the 1/5 solar metallicity, Local Group dwarf galaxy NGC 6822. We achieve high (0.9 arcsec ~ 2 pc) spatial resolution while covering large area: four 250 pc x 250 pc regions that encompass…
We present an analysis of the outer Galaxy giant molecular filament (GMF) G214.5-1.8 (G214.5) using IRAM 30m data of $^{12}$CO, $^{13}$CO and C$^{18}$O. We find that the $^{12}$CO (1-0) and (2-1) derived excitation temperatures are near…
We analyze the hierarchical structure in the Rosette Molecular Cloud (RMC) using $^{13}$CO J=1-0 data from the Milky Way Imaging Scroll Painting (MWISP) survey with a non-binary Dendrogram algorithm that allows multiple branches to emerge…
We present a large-scale simultaneous survey of the CO isotopologues ($\rm {}^{12}{CO}$, $\rm{}^{13}{CO}$, and $\rm{C}{}^{18}{O}$) J = 1 ${-}$ 0 line emission toward the Galactic plane region of l = 106.65$^\circ$ to 109.50$^\circ$ and b =…
We have constructed three-dimensional models for the equilibrium abundance of molecular hydrogen within diffuse interstellar clouds of arbitrary geometry that are illuminated by ultraviolet radiation. The position-dependent photo-…
We discuss the interstellar absorption from many atomic and molecular species seen in high-resolution $HST$/STIS UV and high-S/N optical spectra of the moderately reddened B3-5~V star HD~62542. This remarkable sight line exhibits both very…
We study the molecular gas properties of two star-forming galaxies separated by 6 kpc in the projected space and belonging to a galaxy cluster selected from the Irac Shallow Cluster Survey, at a redshift $z=1.2$, i.e., $\sim2$ Gyr after the…
We present a large catalogue of molecular clouds with accurate distance estimates in the southern sky. Based on the three-dimensional (3D) dust extinction map and the best-fit extinction and distance information of over 17 million stars…
We present new observations of the quiescent giant molecular cloud GCM0.253+0.016 in the Galactic center, using the upgraded Karl G. Jansky Very Large Array. Observations were made at wavelengths near 1 cm, at K (24 to 26 GHz) and Ka (27…
Young massive stars and stellar clusters continuously form in the Galactic disk, generating new HII regions within their natal giant molecular clouds and subsequently enriching the interstellar medium via their winds and supernovae. Massive…
The most usual tracer of molecular gas is line emission from CO. However, the reliability of that tracer has long been questioned in environments different from the Milky Way. We study the relationship between H2 and CO abundances using a…
We present observations of CO(3-2) and $^{13}$CO(3-2) emission near the supernebula in the dwarf galaxy NGC 5253, which contains one of the best examples of a potential globular cluster in formation. The 0.3" resolution images reveal an…