PHANGS-Halpha : A narrow-band survey of nearby star-forming galaxies observed with ALMA

This work collects a representative sample of star-forming galaxies as part of a major effort the Physics at High Angular resolution in Nearby GalaxieS (PHANGS) collaboration has been making to build surveys with matched cloud-scale resolutions. Observations resolved at 50–150 pc are necessary to isolate individual Giant Molecular Clouds (GMCs) and HII regions to probe different phases of star formation from cold gas to stellar clusters. In this context, this sample stems from the PHANGS-ALMA survey to obtain Hα emission-line images from narrow-band photometry for each galaxy observed with ALMA. Integrated Hα emission-line fluxes are derived for 65 nearby galaxies observed during a two-year campaign conducted at MPG-ESO 2.2-meter telescope in La Silla and at du Pont 2.5-meter telescope in Las Campanas. Observations, data processing, astrometric and flux calibrations, as well as the procedure to extract the final emission-line fluxes, are described in this presentation. Comparisons with spectroscopic Hα fluxes are made as a sanity check on a sub-sample of galaxies with available PHANGS-MUSE observations. We finally explore the size distribution of the Hα emitting disk and present dust-corrected SFR maps from the Hα emission-line fluxes.

04/02/2021 - 12:30
Dr. Alessandro Razza
Univ Chile and Univ Granada. Granada, Spain