A Comparison of Young Star Properties with Local Galactic Environment for LEGUS/LITTLE THINGS Dwarf Irregular Galaxies

Hunter, Deidre A.; Adamo, Angela; Elmegreen, Bruce G.; Gallardo, Samavarti; Lee, Janice C.; Cook, David O.; Thilker, David; Kayitesi, Bridget; Kim, Hwihyun; Kahre, Lauren; Ubeda, Leonardo; Bright, Stacey N.; Ryon, Jenna E.; Calzetti, Daniela; Tosi, Monica; Grasha, Kathryn; Messa, Matteo; Fumagalli, Michele; Dale, Daniel A.; Sabbi, Elena; Cignoni, Michele; Smith, Linda J.; Gouliermis, Dimitrios M.; Grebel, Eva K.; Aloisi, Alessandra; Whitmore, Bradley C.; Chandar, Rupali; Johnson, Kelsey E.

doi:10.3847/1538-3881/aac50e

A Comparison of Young Star Properties with Local Galactic Environment for LEGUS/LITTLE THINGS Dwarf Irregular Galaxies

Hunter, Deidre A.; Adamo, Angela; Elmegreen, Bruce G.; Gallardo, Samavarti; Lee, Janice C.; Cook, David O.; Thilker, David; Kayitesi, Bridget; Kim, Hwihyun; Kahre, Lauren; Ubeda, Leonardo; Bright, Stacey N.; Ryon, Jenna E.; Calzetti, Daniela; Tosi, Monica; Grasha, Kathryn; Messa, Matteo; Fumagalli, Michele; Dale, Daniel A.; Sabbi, Elena; Cignoni, Michele; Smith, Linda J.; Gouliermis, Dimitrios M.; Grebel, Eva K.; Aloisi, Alessandra; Whitmore, Bradley C.; Chandar, Rupali; Johnson, Kelsey E.

Authors

Deidre A. Hunter

Angela Adamo

Bruce G. Elmegreen

Samavarti Gallardo

Janice C. Lee

David O. Cook

David Thilker

Bridget Kayitesi

Hwihyun Kim

Lauren Kahre

Leonardo Ubeda

Stacey N. Bright

Jenna E. Ryon

Daniela Calzetti

Monica Tosi

Kathryn Grasha

Matteo Messa

Professor Michele Fumagalli michele.fumagalli@durham.ac.uk
Academic Visitor

Daniel A. Dale

Elena Sabbi

Michele Cignoni

Linda J. Smith

Dimitrios M. Gouliermis

Eva K. Grebel

Alessandra Aloisi

Bradley C. Whitmore

Rupali Chandar

Kelsey E. Johnson

Abstract

We have explored the role environmental factors play in determining characteristics of young stellar objects in nearby dwarf irregular and blue compact dwarf galaxies. Star clusters are characterized by concentrations, masses, and formation rates; OB associations by mass and mass surface density; O stars by their numbers and near-ultraviolet absolute magnitudes; and H ii regions by Hα surface brightnesses. These characteristics are compared to surrounding galactic pressure, stellar mass density, H i surface density, and star formation rate (SFR) surface density. We find no trend of cluster characteristics with environmental properties, implying that larger-scale effects are more important in determining cluster characteristics or that rapid dynamical evolution erases any memory of the initial conditions. On the other hand, the most massive OB associations are found at higher pressure and H i surface density, and there is a trend of higher H ii region Hα surface brightness with higher pressure, suggesting that a higher concentration of massive stars and gas is found preferentially in regions of higher pressure. At low pressures we find massive stars but not bound clusters and OB associations. We do not find evidence for an increase of cluster formation efficiency as a function of SFR density. However, there is an increase in the ratio of the number of clusters to the number of O stars with increasing pressure, perhaps reflecting an increase in clustering properties with SFR.

Citation

Hunter, D. A., Adamo, A., Elmegreen, B. G., Gallardo, S., Lee, J. C., Cook, D. O., …Johnson, K. E. (2018). A Comparison of Young Star Properties with Local Galactic Environment for LEGUS/LITTLE THINGS Dwarf Irregular Galaxies. Astronomical Journal, 156(1), Article 21. https://doi.org/10.3847/1538-3881/aac50e

Journal Article Type	Article
Acceptance Date	May 13, 2018
Online Publication Date	Jun 21, 2018
Publication Date	Jun 21, 2018
Deposit Date	Jul 5, 2018
Publicly Available Date	Jul 5, 2018
Journal	Astronomical Journal
Print ISSN	0004-6256
Publisher	IOP Publishing
Peer Reviewed	Peer Reviewed
Volume	156
Issue	1
Article Number	21
DOI	https://doi.org/10.3847/1538-3881/aac50e