Year: 2026
Type: article
Abstract: We report redshifted cool gas toward the central star-forming region of the nearby starburst dwarf galaxy NGC 4214. Hubble Space Telescope/Cosmic Origins Spectrograph (COS) spectra show low-ionization absorbers redshifted relative to the systemic velocity, most clearly in S ii (Δ v = 19.8 ± 2.6 km s −1 ) and supported by Mg ii (Δ v = 30.3 ± 3.0 km s −1 ), while P ii remains tentative (Δ v = 7.5 ± 3.4 km s −1 ). The Keck/HIRES spectra also reveal a redshifted Ca ii absorption component (Δ v = 25.6 ± 1.5 km s −1 ). Because the absorption is detected against the central UV or optical continuum, the gas must lie in the foreground of the star-forming region and be moving away from the observer and toward the background UV source in projection. A Very Large Array (VLA)–THINGS H i spectrum extracted at the COS position within one VLA beam also shows a redshifted neutral component at v hel = 329.2 ± 0.9 km s −1 , offset by 38.2 ± 1.3 km s −1 from systemic and by 27.6 ± 1.0 km s −1 from the dominant local H i component. The FAST H i mapping further reveals an extended, kinematically disturbed neutral disk, with residual structures relative to a warped-disk model. Together, the redshifted UV absorption, the redshifted H i component, and the disturbed large-scale H i velocity field show that the central anomalous cool gas is observed in a galaxy with a disturbed extended neutral disk. This geometry suggests that the redshifted cool gas may trace inflow or recycled fallback toward the central region, although warped-disk or noncircular disk motions cannot be fully excluded.
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,400
OpenAlex ID: W7221543347