Narrowband H$\alpha$ imaging of nearby Wolf-Rayet galaxies

TL;DR

This study uses narrowband Hα imaging to analyze star-forming regions and star formation rates in nearby Wolf-Rayet galaxies, revealing their morphological features and evolutionary similarities to normal star-forming galaxies.

Contribution

First to establish the Main-Sequence relation for nearby Wolf-Rayet galaxies, showing their evolution parallels that of normal star-forming galaxies.

Findings

Hα images reveal star-forming region morphology suggestive of mergers or interactions.

Hα-based SFRs correlate well with UV, IR, and radio indicators.

The derived Main-Sequence relation for WR galaxies is similar to that of normal galaxies.

Abstract

We present narrowband H$\alpha$ imaging of nearby Wolf-Rayet (WR) galaxies known as a subset of starburst galaxies. The H$\alpha$ images have been used to show morphology of star-forming regions in galaxies, which leads to speculate that the studied galaxies have most likely experienced merger or interaction with low luminous dwarf galaxies or \HI clouds. We further derive the H$\alpha$ based star formation rates (SFRs) in galaxies using our H$\alpha$ observations. These SFRs are well-correlated with SFRs derived using other indicators at far-ultraviolet, far-infrared and 1.4-GHz radio wavebands. It is noticed that the infrared excess (IRX) method gives the best SFR estimates, consistent with different models predication. These models also predict that the sample galaxies have probably gone through a continuous star formation at least for 1 Gyr over which the recent (< 10 Myr) star formation has taken place in WR phase. This study presents Main-Sequence (MS) relation for nearby WR galaxies for the first time. This derived MS relation is found to be similar to previously known MS relation for normal nearby star-forming galaxies, suggesting that WR systems evolve in a similar fashion as normal star-forming galaxies evolve.