CON-quest: Searching for the most obscured galaxy nuclei

摘要: Some luminous and ultraluminous infrared galaxies (LIRGs ULIRGs) host extremely compact dusty nuclei. The intense radiation arising from warm dust in these sources is prone to excite vibrational levels of molecules such as HCN. This results emission the rotational transitions vibrationally excited HCN (HCN-vib), with brightest found obscured nuclei (CONs). We aim establish how common CONs are local Universe, whether their prevalence depends on luminosity or other properties galaxy. have conducted an Atacama Large Millimeter/submillimeter Array (ALMA) survey J=3-2 transition HCN-vib a sample 46 far-infrared galaxies. Compact identified 38 percent ULIRGs, 21 LIRGs, 0 lower find no dependence inclination galaxy, but strong evidence IRAS 25 60 {\mu}m flux density ratios (f25/f60) compared rest sample. Furthermore, we that stronger silicate features (s9.7{\mu}m) similar PAH equivalent widths (EQW6.2{\mu}m) In primarily (U)LIRGs. High resolution continuum observations individual required determine if CON phenomenon related inclinations nuclear disks. f25/f60 well for mid-infrared diagnostics investigated consistent large columns shifting longer wavelengths, making mid- "photospheres" significantly cooler than interior regions. To assess importance context galaxy evolution, it necessary extend this study higher redshifts where (U)LIRGs more common.