Related papers: Enhanced Dense Gas Fraction in Ultra-Luminous Infr…

New HCN, HNC, and HCO+ measurements of 46 normal galaxies in transitions up to J=4-3 are included in a multitransition database covering HCN and HCO+ (130 galaxies) and HNC (94 galaxies). The near-linear luminosity relations are dominated…

Millimeter (CO) observations of 5 double-nucleus ultraluminous infrared galaxy (ULIG) mergers are presented. With nuclear separations of 3-5 kpc, these galaxies are in the ``intermediate'' stages of the merger process. A preliminary…

We fit the near-infrared to radio spectral energy distributions of 30 luminous and ultra-luminous infrared galaxies with pure starburst models or models that include both starburst and AGN components to determine important physical…

The observed molecular properties of a sample of FIR-luminous and OH megamaser (OH-MM) galaxies have been investigated. The ratio of high and low-density tracer lines is found to be determined by the progression of the star formation in the…

We present the results of our ALMA observations of eleven (ultra)luminous infrared galaxies ((U)LIRGs) at J=4-3 of HCN, HCO+, HNC and J=3-2 of HNC. This is an extension of our previously published HCN and HCO+ J=3-2 observations to multiple…

Compiling data from literature and the ALMA archive, we show enhanced HCN(4-3)/HCO$^+$(4-3) and/or HCN(4-3)/CS(7-6) integrated intensity ratios in circumnuclear molecular gas around active galactic nuclei (AGNs) compared to those in…

We present interferometric observations of three ultraluminous infrared galaxies (ULIRGs; UGC 5101, Mrk 273, and IRAS 17208-0014) in the 3-mm wavelength range, using the Nobeyama Millimeter Array. Both the HCN (J=1-0) and HCO+ (J=1-0)…

Nuclear regions of ultraluminous and luminous infrared galaxies (U/LIRGs) are powered by starbursts and/or active galactic nuclei (AGNs). These regions are often obscured by extremely high columns of gas and dust. Molecular lines in the…

Observations of carbon monoxide (CO) emission in high redshift (z>2) galaxies indicate the presence of large amounts of molecular gas. Many of these galaxies contain an active galactic nucleus (AGN) powered by accretion of gas onto a…

We examine the origin of molecular gas heating in a sample of 42 infrared-luminous galaxies at $z<0.3$ by combining two sets of archival data. First, integrated CO line luminosities in the 1-0 and 5-4 through 13-12 transitions. Second,…

We present new IRAM 30m spectroscopic observations of the $\sim88$ GHz band, including emission from the CCH (n=1-0) multiplet, HCN (1-0), HCO+ (1-0), and HNC (1-0), for a sample of 58 local luminous and ultraluminous infrared galaxies from…

We present a survey of 3 mm molecular lines in IRAS 04296+2923, one of the brightest known molecular-line emitting galaxies, and one of the closest LIRGs. Data are from the Owens Valley and CARMA millimeter interferometers. Species detected…

We study the r31=L'CO(3-2)/L'CO(1-0) luminosity line ratio in a sample of nearby (z < 0.05) galaxies: 25 star-forming galaxies (SFGs) from the xCOLD GASS survey, 36 hard X-ray selected AGN host galaxies from BASS and 37 infrared luminous…

The observational study of star formation relations in galaxies is central to unraveling the physical processes at work on local and global scales. We wish to expand the sample of extreme starbursts, represented by local LIRGs and ULIRGs,…

We perform photometric measurements on a large HST snapshot imaging survey sample of 97 ultraluminous infrared galaxies (ULIRGs). We select putative nuclei from bright clumps in all the sample targets, mainly based on a quantitative…

A tight linear correlation is established between the HCN line luminosity and the radio continuum (RC) luminosity for a sample of 65 galaxies (from Gao & Solomon's HCN survey), including normal spiral galaxies and luminous and ultraluminous…

Dense molecular gas and star formation are correlated in galaxies. The effect of low metallicity on this relationship is crucial for interpreting observations of high redshift galaxies, which have lower metallicities than galaxies today.…

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…

We present the results on millimeter interferometric observations of four luminous infrared galaxies (LIRGs), Arp 220, Mrk 231, IRAS 08572+3915, and VV 114, and one Wolf-Rayet galaxy, He 2-10, using the Nobeyama Millimeter Array (NMA). Both…

In order to understand the evolution and feedback of Active Galactic Nuclei (AGN) and star formation it is important to use molecular lines as probes of physical conditions and chemistry. We use H$_{2}$S to investigate the impact of…