Leader: Jong Chul Lee

Email: jclee@kasi.re.kr

Collaborators: Anyone interested in this subject

Topic:

The unexpected dynamics of low-mass dwarf galaxies
The kinematic properties of Milky Way analogues
Inflows and outflows at large radius
The future fate of ram-pressure affected cluster galaxies

Status: under review by Science Committee

Abstract: The dust attenuation effects should be accounted for when deriving intrinsic galaxy properties. It is well known that dust attenuation towards gas emission lines (gas attenuation) is a factor of two larger than dust attenuation applied to the stellar continuum (stellar attenuation), and stellar attenuation curves vary from galaxy to galaxy and/or region to region. However, there is little information on the shape of gas attenuation curves. By using three or more Balmer lines simultaneously (Hα, Hβ, Hγ, and Hδ) from the deep Hector spectra, we plan to constrain the slope of gas attenuation curves and investigate how this slope varies with physical properties.

With recent IFS surveys, maps of star formation rate (SFR) and dust attenuation can be obtained for a large number of galaxies. However, most previous studies have focused on the radial distributions of SFR and dust, not fully utilizing the spatial information. We plan to explore both their compactness and clumpiness along and across the star-forming main sequence.

The observed Hα/Hβ line ratio (the so-called Balmer decrement) is generally higher than its theoretical value of ~2.86 in HII regions due to the dust reddening effect. The number fraction of cases with a Balmer decrement less than 2.86 is usually negligible in integrated spectra, but it appears to be up to 20 percent in IFS data. We need to compare these spaxels with others in various parameter spaces to understand their origin (maybe diffuse ionized gas regions).

Numerous studies of SFR and dust attenuation have been conducted using typical star-forming galaxies. We hope to expand these studies to more extreme cases, such as starburst, early-type, and dwarf galaxies, based on the Hector survey data, which covers a variety of galaxies.

Needed data products: emission line maps, stellar mass map, and galaxy parameters

Publication Date: 30/06/2026