相关论文: Dense Gas in the Outer Spiral Arm of M51
We present the spatially-resolved observations of HCN J = 1 -- 0 emission in the nearby spiral galaxy M51 using the IRAM 30 m telescope. The HCN map covers an extent of $4\arcmin\times5\arcmin$ with spatial resolution of $28\arcsec$, which…
Observations of 12CO J=1-0 and HCN J=1-0 emission from NGC 5194 (M51) made with the 50~meter Large Millimeter Telescope and the SEQUOIA focal plane array are presented. Using the HCN to CO ratio, we examine the dense gas mass fraction over…
Stars form out of the densest parts of molecular clouds. Far-IR emission can be used to estimate the Star Formation Rate (SFR) and high dipole moment molecules, typically HCN, trace the dense gas. A strong correlation exists between HCN and…
We present maps and spectra of the HCN(1-0) and HCO$^+$(1-0) lines in the extreme outer Galaxy, at galactocentric radii between 14 and 22 kpc, with the 13.7 meter Delingha telescope. The 9 molecular clouds were selected from a CO/$^{13}$CO…
Dense, cold gas is the key ingredient for star formation. Over the last two decades, HCN(1-0) emission has been utilised as the most accessible dense gas tracer to study external galaxies. We present new measurements tracing the…
The star formation rate (SFR) is tightly connected to the amount of dense gas in molecular clouds. However, it is not fully understood how the relationship between dense molecular gas and star formation varies within galaxies and in…
We aim to better understand the emission of molecular tracers of the diffuse and dense gas in giant molecular clouds and the influence that metallicity, optical extinction, density, far-UV field, and star formation rate have on these…
It remains unclear what sets the efficiency with which molecular gas transforms into stars. Here we present a new VLA map of the spiral galaxy M51 in 33GHz radio continuum, an extinction-free tracer of star formation, at 3" scales (~100pc).…
We report observations made with the IRAM 30m radiotelescope in the HCN(1-0) and HCO+(1-0) lines towards a sample of molecular complexes (GMCs) in the disk of the Andromeda galaxy (M31). The targets were identified bright CO GMCs selected…
We use the CARMA millimeter interferometer to map the Antennae Galaxies (NGC4038/39), tracing the bulk of the molecular gas via the 12CO(1-0) line and denser molecular gas via the high density transitions HCN(1-0), HCO+(1-0), CS(2-1), and…
Studies both of entire galaxies and of local Galactic star formation indicate a dependency of a molecular cloud's star formation rate (SFR) on its dense gas mass. In external galaxies, such measurements are derived from HCN(1-0)…
We have mapped HCN and HCO$^{+}$ (J = 1 $\to$ 0) line emission toward a sample of seven star-forming regions (with 12 + log[O/H] range from 8.34 to 8.69) in the outer Milky Way (Galactocentric distance > 9.5 kpc), using the 14-meter radio…
We present the 3 mm wavelength spectra of 28 local galaxy merger remnants obtained with the Large Millimeter Telescope. Fifteen molecular lines from 13 different molecular species and isotopologues were identified, and 21 out of 28 sources…
Both Galactic and extragalactic studies on star formation suggest that stars form directly from dense molecular gas. To trace such high volume density gas, HCN and HCO+ J=1-0 have been widely used for their high dipole moments, relatively…
We present 3 mm and 2 mm band simultaneously spectroscopic observations of HCN 1-0, HCO$^{+}$ 1-0, HNC 1-0, and CS 3-2 with the IRAM 30 meter telescope, toward a sample of 70 sources as nearby galaxies with infrared luminosities ranging…
We present a new survey of HCN(1-0) emission, a tracer of dense molecular gas, focused on the little-explored regime of normal star-forming galaxy disks. Combining HCN, CO, and infrared (IR) emission, we investigate the role of dense gas in…
We report HCN J=4-3, HCO+ J=4-3, and CS J=7-6 observations in 20 nearby star-forming galaxies with the Acatama Pathfinder EXperiment 12-m telescope. Combined with 4 HCN, 3 HCO+, and 4 CS detections in literature, we probe the empirical link…
It is still poorly constrained how the densest phase of the interstellar medium varies across galactic environment. A large observing time is required to recover significant emission from dense molecular gas at high spatial resolution, and…
We present the results of high-resolution 13CO(1-0) mapping observations with the NRO 45m telescope of the area toward the southern bright arm region of M51, including the galactic center. The obtained map shows the central depression of…
We use new ALMA observations to investigate the connection between dense gas fraction, star formation rate, and local environment across the inner region of four local galaxies showing a wide range of molecular gas depletion times. We map…