TY - JOUR
T1 - The Environments of CO Cores and Star Formation in the Dwarf Irregular Galaxy WLM
AU - Archer, Haylee N.
AU - Hunter, Deidre A.
AU - Elmegreen, Bruce G.
AU - Cigan, Phil
AU - Jansen, Rolf A.
AU - Windhorst, Rogier A.
AU - Hunt, Leslie K.
AU - Rubio, Monica
N1 - Funding Information:
The VLA, now the Karl G. Jansky Very Large Array, is a facility of the National Radio Astronomy Observatory. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. Observations were made during the transition from the Very Large Array to the Karl G. Jansky Very Large Array. 8
Publisher Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.
PY - 2022/3/1
Y1 - 2022/3/1
N2 - The low metallicities of dwarf irregular galaxies (dIrr) greatly influence the formation and structure of molecular clouds. These clouds, which consist primarily of H2, are typically traced by CO, but low-metallicity galaxies are found to have little CO despite ongoing star formation. In order to probe the conditions necessary for CO core formation in dwarf galaxies, we have used the catalog of Rubio et al. for CO cores in WLM, a Local Group dwarf with an oxygen abundance that is 13% of solar. Here we aim to characterize the galactic environments in which these 57 CO cores formed. We grouped the cores together based on proximity to each other and strong FUV emission, examining properties of the star-forming region enveloping the cores and the surrounding environment where the cores formed. We find that high H i surface density does not necessarily correspond to higher total CO mass, but regions with higher CO mass have higher H i surface densities. We also find the cores in star-forming regions spanning a wide range of ages show no correlation between age and CO core mass, suggesting that the small size of the cores is not due to fragmentation of the clouds with age. The presence of CO cores in a variety of different local environments, along with the similar properties between star-forming regions with and without CO cores, leads us to conclude that there are no obvious environmental characteristics that drive the formation of these CO cores.
AB - The low metallicities of dwarf irregular galaxies (dIrr) greatly influence the formation and structure of molecular clouds. These clouds, which consist primarily of H2, are typically traced by CO, but low-metallicity galaxies are found to have little CO despite ongoing star formation. In order to probe the conditions necessary for CO core formation in dwarf galaxies, we have used the catalog of Rubio et al. for CO cores in WLM, a Local Group dwarf with an oxygen abundance that is 13% of solar. Here we aim to characterize the galactic environments in which these 57 CO cores formed. We grouped the cores together based on proximity to each other and strong FUV emission, examining properties of the star-forming region enveloping the cores and the surrounding environment where the cores formed. We find that high H i surface density does not necessarily correspond to higher total CO mass, but regions with higher CO mass have higher H i surface densities. We also find the cores in star-forming regions spanning a wide range of ages show no correlation between age and CO core mass, suggesting that the small size of the cores is not due to fragmentation of the clouds with age. The presence of CO cores in a variety of different local environments, along with the similar properties between star-forming regions with and without CO cores, leads us to conclude that there are no obvious environmental characteristics that drive the formation of these CO cores.
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U2 - 10.3847/1538-3881/ac4e88
DO - 10.3847/1538-3881/ac4e88
M3 - Article
AN - SCOPUS:85125713865
SN - 0004-6256
VL - 163
JO - Astronomical Journal
JF - Astronomical Journal
IS - 3
M1 - 141
ER -