Oral Presentation

3 mm Galaxy Number Counts and Physical Properties of Dusty Galaxies

Author(s): Qi-Ning, Hsu (Institute of Astronomy in National Tsing Hua University)

Presenter: Qi-Ning Hsu (NTHU)

Millimeter and submillimeter observations with the Atacama Large Millimeter/Submillimeter Array (ALMA) provide a unique window into the dust-obscured universe, revealing galaxies that remain hidden in optical and infrared surveys. Understanding these dusty galaxies is essential for advancing galaxy formation theories. This project focuses on the AS2COSPEC survey, which leverages ALMA to conduct a 3 mm study of dusty star-forming galaxies at z∼2−5 (Chen et al., 2022, ApJ, 929, 159). Using the deep ALMA 3 mm continuum data from AS2COSPEC, we aim to derive precise galaxy number counts and investigate the statistical distribution and physical properties of galaxies emitting at this wavelength. To further characterize these sources, we employ MAGPHYS to fit their spectral energy distributions (SEDs), estimating photometric redshifts and key physical properties such as stellar mass, dust content, and star formation rates. This analysis has the potential to identify dusty star-forming galaxies at high redshifts—an essential epoch for galaxy evolution studies—especially in light of recent discoveries from the James Webb Space Telescope (JWST). Additionally, we seek to constrain the redshift distribution of ALMA-detected 3 mm sources, which remains poorly understood and is critical for refining galaxy formation models.