Tracing Winds through the Fog: A Comprehensive Survey of LMC's Galactic Outflows with ULLYSES
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 Hα 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 vLMCSR ≈ −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≲ vLSR ≲ +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 ∼1.8×107 M⊙, implying Ṁout≈0.15-0.33 M⊙ yr−1 and a mass-loading factor of η≈0.6-1.3. On regional scales, 30 Doradus contributes ∼10% and N11 contributes ∼3% 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.
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BibTeX
@misc{poudel2026tracing,
title = {{Tracing Winds through the Fog: A Comprehensive Survey of LMC's Galactic Outflows with ULLYSES}},
author = {Suraj Poudel and April Horton and Kathleen A. Barger and Frances H. Cashman and Jo Vazquez and Andrew J. Fox and Nicolas Lehner and J. Christopher Howk and Scott Lucchini and Dhanesh Krishnarao and Sabra Catalano and Anders Ripley and Wanyan Yuan and Natalie Van Tol and Citlali Alcala and Jordan Elliott and N. M. McClure Griffiths and Elena D'Onghia and Jason Tumlinson and Ananya Goon Tuli and Jacco Th. van Loon and Julia Roman-Duval and Yik Ki Ma and Callum Lynn},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.32137},
eprint = {2609.32137},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.32137},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Tracing Winds through the Fog: A Comprehensive Survey of LMC's Galactic Outflows with ULLYSES
AU - Suraj Poudel
AU - April Horton
AU - Kathleen A. Barger
AU - Frances H. Cashman
AU - Jo Vazquez
AU - Andrew J. Fox
AU - Nicolas Lehner
AU - J. Christopher Howk
AU - Scott Lucchini
AU - Dhanesh Krishnarao
AU - Sabra Catalano
AU - Anders Ripley
AU - Wanyan Yuan
AU - Natalie Van Tol
AU - Citlali Alcala
AU - Jordan Elliott
AU - N. M. McClure Griffiths
AU - Elena D'Onghia
AU - Jason Tumlinson
AU - Ananya Goon Tuli
AU - Jacco Th. van Loon
AU - Julia Roman-Duval
AU - Yik Ki Ma
AU - Callum Lynn
PY - 2026
DA - 2026/09/26
PB - arXiv
DO - 10.48550/arxiv.2609.32137
UR - https://arxiv.org/abs/2609.32137
AB - 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_LMCSR ≈ −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≲ v_LSR ≲ +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 ∼1.8×10^7 M_⊙, implying Ṁ_out≈0.15-0.33 M_⊙ yr^−1 and a mass-loading factor of η≈0.6-1.3. On regional scales, 30 Doradus contributes ∼10% and N11 contributes ∼3% 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.
ER -