Oral Presentation
ALMA observations of infrared-bright dust-obscured galaxies
Presenter: Yoshiki Toba (ASIAA)
We present ALMA observations of extremely infrared-bright dust-obscured galaxies (DOGs). A prominent feature of DOGs is very faint in the optical, but bright in the infrared (IR), i.e., flux (mid-IR) / flux (optical) > 1000. This implies dust heating either by significant star formation (SF), an active galactic nucleus (AGN) , or both, and the bulk of the optical and UV emission from them is absorbed by surrounding dust. In particular, IR-bright DOGs are likely to be a key population to understand the growing phase of the co-evolution between galaxies and supermassive black holes. Investigating how the molecular gas outflow affects the SF activity in the IR-bright DOGs is crucial to tackle the mystery of the co-evolution behind the dust.
We are performing the IR-bright DOGs search and have investigated their statistical properties (Toba et al. 2015, 2016, 2017a). Recently, we discovered 67 extremely IR-bright DOGs over the largest survey footprint so far combining the SDSS (optical) data with WISE (mid-IR) data (Toba & Nagao 2016). Among them, we discovered four curious objects that show a clear outflow associated with ionized gasses ([OIII]) outflow in their optical spectra (Toba et al. 2017b in prep.), although whether or not the molecular gasses are also associated with outflow is unclear. We present the physical properties of molecular gasses in two DOGs through the observations of 12CO (J=4--3), 12CO (J=2--1) as well as continuum.
asiaa.sinica.edu.tw