FLASH Talks: Michael Jones (Steward) & Samuel Crowe (University of Virginia)
Friday, 29 September 2023 noon — 1 p.m. MST
NOIRLab Headquarters | 950 North Cherry Ave., Tucson, AZ 85719
Michael Jones, Steward Observatory
Pavo: Discovery of a new low-mass dwarf galaxy just outside the Local Group
I will present the discovery of a new extremely low-mass, isolated, and star-forming dwarf galaxy just outside the Local Group, which we have named Pavo. Pavo was identified as part of a search of the DESI Legacy Imaging surveys for semi-resolved, low-mass galaxies. This search relied on a convolutional neural network image classifier, retrained specifically to identify semi-resolved low-mass galaxies. Follow-up IMACS imaging of Pavo revealed both a young and old stellar population, and enabled a tip-of-the-red-giant branch distance estimate (2.0 Mpc). Given this distance, we estimate the total stellar mass of Pavo is just 4 x 10^5 Msol. Pavo is therefore a close analog of the famous dwarf galaxy Leo P, but is even more isolated and slightly lower mass. This discovery underscores the power of machine learning as a means to push imaging searches into regimes where traditional algorithms have struggled to make headway, and thus to maximize the discovery potential of upcoming imaging surveys.
Samuel Crowe, University of Virginia
Near-Infrared Observations of Massive Star Formation: Revealing Omnidirectional Outflows in AFGL 5180 with the LBT
Massive stars are significant throughout the universe, as they impact their surroundings from the early stages of their formation until they die in the form of supernova. Observations in the near-infrared (NIR) of the bright and large-scale (~pc) jets which young stars ubiquitously produce during their formation process can place important constraints on the phenomenon of massive star formation. Here, I present a detailed NIR view of the massive star-forming region AFGL 5180 utilizing imaging from the Large Binocular Telescope (LBT) with both seeing-limited and extremely high-resolution (~90 mas) Adaptive Optics data, as well as imaging from the Hubble Space Telescope (HST). This unprecedented view into the AFGL 5180 complex reveals highly clustered star formation, evidenced by the presence of several multidirectional outflows and confirmed by the detection of over a dozen compact sub-millimeter sources using data from the Atacama Large Millimeter/Submillimeter Array (ALMA). High stellar densities in the vicinity of the central massive (~12 Msun) protostar agree favorably with recent numerical simulations and indicate that low- and high-mass star formation is occurring in AFGL 5180 in a crowded manner, shedding light on the process of star formation.