Tracing Winds through the Fog: A Comprehensive Survey of LMC's Galactic Outflows with ULLYSES
Year: 2026
Type: preprint
Abstract: We investigate nearside stellar-driven outflows from the Large Magellanic Cloud (LMC) using UV absorption-line spectroscopy of 170 OB stars, complemented by HI 21-cm emission and H$_α$ emission. Using Voigt-profile fitting and AOD analysis of SiII, OI, and SII transitions, we map the velocity-dependent structure of foreground gas. The SiII column densities for the Voigt-fitted components decline smoothly from the LMC disk and reach a minimum at $v_{\rm LMCSR} \approx -100$ to $-200~{km~s^{-1}}$, marking the transition from a denser, slower wind to more diffuse high-velocity material. Comparisons with local star-formation rate surface densities reveal a modest positive correlation for the slower wind component, linking it to recent massive-stellar feedback. Photoionization modeling of 13 absorbers in the $+100\lesssim v_{\rm LSR} \lesssim +150~{km~s^{-1}}$ range reveals wide diversity in metallicity, dust depletion, and ionization conditions, consistent with multiple possible origins. While a substantial fraction of this predominately ionized gas is consistent with the high-velocity extension of the LMC wind, part of it may arise from contamination by Milky Way (MW) high-velocity clouds (HVCs) and Magellanic circumgalactic medium (CGM). We estimate a nearside cool-gas outflow mass of ${\sim}1.8\times10^{7}\,M_{\odot}$, implying $\dot{M}_{\rm out}\approx0.15$-$0.33\,M_{\odot}\,\mathrm{yr^{-1}}$ and a mass-loading factor of $η\approx0.6$-1.3. On regional scales, 30 Doradus contributes $\sim10\%$ and N11 contributes $\sim3\%$ of the total outflow mass, while the trailing side contains more wind material than the leading side, consistent with ram-pressure stripping. These results provide the comprehensive kinematic and physical characterization of how stellar feedback, galactic environment, and foreground contamination shape the multiphase wind emerging from the LMC.
Source: arXiv (Cornell University)
Authors: Poudel, Suraj, Horton, April, Barger, Kathleen A., Cashman, Frances H., Vazquez, Jo, Fox, Andrew J., Lehner, Nicolas, Howk, J. Christopher, Lucchini, Scott, Krishnarao, Dhanesh, Catalano, Sabra, Ripley, Anders, Yuan, Wanyan, Van Tol, Natalie, Alcala, Citlali, Elliott, Jordan, Griffiths, N. M. McClure, D'Onghia, Elena, Tumlinson, Jason, Tuli, Ananya Goon, van Loon, Jacco Th., Roman-Duval, Julia, Ma, Yik Ki, Lynn, Callum
Institutions: Texas Christian University, Presbyterian College, Space Telescope Science Institute, University of Notre Dame, Center for Astrophysics Harvard & Smithsonian, Colorado College, University of Wisconsin–Madison, Keele University, Max Planck Institute for Radio Astronomy, Australian National University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, National Aeronautics and Space Administration, Science and Industry Endowment Fund, Space Telescope Science Institute, Australian Government, Commonwealth Scientific and Industrial Research Organisation, Universität Wien, Uppsala Universitet, Government of Western Australia
OpenAlex ID: W7214794727