Power-law Emission-line Wings and Radiation-driven Superwinds in Local Lyman Continuum Emitters
Year: 2025
Type: article
Abstract: We investigate broad emission-line wings, reaching ≤800 km s −1 , observed in 26 galaxies with Lyman continuum (LyC) observations, primarily from the Low-redshift Lyman Continuum Survey. Using Magellan/MIKE, Very Large Telescope/X-shooter, and WHT/ISIS high-resolution spectroscopy, we show that this fast gas appears to probe the dominant feedback mechanisms linked to LyC escape. We find that in 14 galaxies, the wings are best-fit with power laws of slope α ∼ −3.5 to −1.6, with four others best fit by Gaussians of width σ BW ∼ 300 km s −1 ; the remaining eight show ambiguous wing morphologies. Gaussian wings are found only at low O 32 = [O III ] λ 5007/[O II ] λ 3726, 3729 and high metallicity, while power-law wings span the full range of these parameters. The general evidence suggests a dual-mode paradigm for LyC escape: radiation-driven superwinds traced by power-law wings and supernova-driven feedback traced by Gaussian wings. For the former, the <3 Myr-old, pre-supernova stellar population correlates with more luminous, faster winds. The data also show that radiation-driven wind parameters like wind luminosity and power-law slope α depend on the UV luminosity more than the optically thick covering fraction, consistent with “picket-fence” radiative transfer. Observed α values flatten with both escaping LyC luminosity and higher extinction, while still preserving the anticorrelation between these two quantities. Additionally, the differential between red and blue slopes implies that extinction and dense gas are centrally concentrated relative to the wind emission. Overall, our results show that power-law emission-line wings probe LyC-driven winds and LyC escape in metal-poor starbursts.
Source: The Astrophysical Journal
Authors: Lena Komarova, M. S. Oey, Rui Marques-Chaves, Ricardo Amorín, Alaina Henry, Daniel Schaerer, Alberto Saldana-Lopez, Alexandra Le Reste, Claudia Scarlata, Matthew J. Hayes, Omkar Bait, Sanchayeeta Borthakur, Cody Carr, John Chisholm, Harry C. Ferguson, Vital Gutierrez Fernandez, Brian Fleming, Sophia R. Flury, Mauro Giavalisco, Andrea Grazian, Timothy Heckman, Anne E. Jaskot, Zhiyuan Ji, Göran Östlin, Laura Pentericci, Swara Ravindranath, Trinh Thuan, Jose M. Vílchez, Gabor Worseck, Xinfeng Xu
Institutions: Universitat de València, University of Michigan, University of Geneva, Consejo Superior de Investigaciones Científicas, Instituto de Astrofísica de Andalucía, Space Telescope Science Institute, Stockholm University, AlbaNova, University of Minnesota, SKA Observatory, Arizona State University, Zhejiang University, The University of Texas at Austin, Laboratory for Atmospheric and Space Physics, Royal Observatory, University of Edinburgh, University of Massachusetts Amherst, Osservatorio Astronomico di Padova, Johns Hopkins University, Williams College, University of Arizona, Astronomical Observatory of Rome, National Institute for Astrophysics, University of Virginia, University of Potsdam, Northwestern University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
OpenAlex ID: W4415330349