Related papers: Does the CO-to-H2 conversion factor depend on the …
The star formation efficiency (SFE) measures the proportion of molecular gas converted into stars, while the star formation rate (SFR) indicates the rate at which gas is transformed into stars. Here we propose such a model in the framework…
What main mechanisms set the star formation rate (SFR) of galaxies? This PhD thesis is a quest into the influences of gas and active galactic nuclei (AGNs) on the SFR, with particular focus on massive galaxies at z~2. First, a new code if…
To understand the impact of low metallicities on giant molecular cloud (GMC) structure, we compare far infrared dust emission, CO emission, and dynamics in the star-forming complex N83 in the Wing of the Small Magellanic Cloud. Dust…
H2 column densities towards CO clouds in the LMC and SMC are estimated from their far-infrared surface brightness and HI column density. N(H2)/I(CO) conversion factors are X(LMC) = 1.3 and X(SMC) = 12 (unit: 10**21 mol cm**-2 (K km/s)**-1).…
Cosmic rays (CRs) control the thermal, ionization and chemical state of the dense H_2 gas regions that otherwise remain shielded from far-UV and optical stellar radiation propagating through the dusty ISM of galaxies. It is in such…
A deep, wide-field, near-infrared imaging survey was used to construct an extinction map of the southeastern part of the California Molecular Cloud (CMC) with $\sim$ 0.5 arc min resolution. The same region was also surveyed in the…
Observations show that the coronal X-ray emission of the Sun and other stars depends on the surface magnetic field. Using power-law scaling relations between different physical parameters, we build an analytical model to connect the…
The relations between star formation and properties of molecular clouds are studied based on a sample of star forming regions in the Galactic Plane. Sources were selected by having radio recombination lines to provide identification of…
Star formation is one of the key factors that shapes galaxies. This process is relatively well understood from both simulations and observations on a small "local" scale of individual giant molecular clouds and also on a "global"…
We present evidence that super giant HII regions (GHRs) and other disk regions of the nearby spiral galaxy, M33, occupy distinct locations in the correlation between molecular gas, $\Sigma_{\rm H_2}$, and the star formation rate surface…
We present the first statistical survey of the properties of the 12CO(1-0) and 12CO(3-2) line emission from the nuclei of a nearly complete subsample of 60 infrared (IR) luminous galaxies selected from SCUBA Local Universe Galaxy Survey…
Observations of molecular gas in high-z star-forming galaxies typically rely on emission from CO lines arising from states with rotational quantum numbers J > 1. Converting these observations to an estimate of the CO J=1-0 intensity, and…
We present measurements of the dependence of the clustering amplitude of galaxies on their star formation rate (SFR) and stellar mass ($M_*$) at $0.7 < z < 1.5$ to assess the extent to which environment affects these properties. While these…
We investigate the properties of "star forming regions" in a previously published numerical simulation of molecular cloud formation out of compressive motions in the warm neutral atomic interstellar medium, neglecting magnetic fields and…
We present a new model to describe the star formation process in galaxies, which includes the description of the different gas phases -- molecular, atomic, and ionized -- together with its metal content. The model, which will be coupled to…
We devise a physical model of formation and distribution of molecular gas clouds in galaxies. We use the model to predict the intensities of rotational transition lines of carbon monoxide (CO) and the molecular hydrogen (H$_{\rm 2}$)…
The lines of HOC$^+$, HCO and CO$^+$ are considered good tracers of photon-dominated regions (PDRs) and X-ray dominated regions. We study these tracers towards regions of the Sgr B2 cloud selected to be affected by different heating…
We compare molecular gas traced by 12CO(2-1) maps from the HERACLES survey, with tracers of the recent star formation rate (SFR) across 30 nearby disk galaxies. We demonstrate a first-order linear correspondence between Sig_mol and Sig_SFR…
The observed star formation rate of the Milky Way can be explained by applying a metallicity-dependent factor to convert CO luminosity to molecular gas mass and a star formation efficiency per free-fall time that depends on the virial…
Collisions between giant molecular clouds (GMCs) have been proposed as a mechanism to trigger massive star and star cluster formation. To investigate the astrochemical signatures of such collisions, we carry out 3D magnetohydrodynamics…