Ionized Gas Kinematics and Star-forming Clumps in Extremely Metal-poor Galaxies

@misc{yadav2026ionized,
  title = {{Ionized Gas Kinematics and Star-forming Clumps in Extremely Metal-poor Galaxies}},
  author = {Jyoti Yadav and Casiana Muñoz Tuñón and Cecilia Farina and Alejandro Lumbreras-Calle and Jorge Sánchez Almeida and Bruce G. Elmegreen},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2610.27201},
  eprint = {2610.27201},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2610.27201},
}

TY  - UNPB
TI  - Ionized Gas Kinematics and Star-forming Clumps in Extremely Metal-poor Galaxies
AU  - Jyoti Yadav
AU  - Casiana Muñoz Tuñón
AU  - Cecilia Farina
AU  - Alejandro Lumbreras-Calle
AU  - Jorge Sánchez Almeida
AU  - Bruce G. Elmegreen
PY  - 2026
DA  - 2026/10/19
PB  - arXiv
DO  - 10.48550/arxiv.2610.27201
UR  - https://arxiv.org/abs/2610.27201
AB  - Extremely Metal Poor (XMP) galaxies are the least chemically evolved objects in the local Universe and provide important constraints on galaxy formation in low-metallicity environments. This work investigates the ionised gas kinematics and star formation properties of XMP galaxies to identify disturbed or multi-component gas motions and explore their connection with star formation. We analyse long-slit spectroscopic observations of nine XMP galaxies obtained with the Intermediate Dispersion Spectrograph on the 2.5m Isaac Newton Telescope. The study uses the Hα emission line to trace ionised gas and emission-line ratios to derive gas-phase metallicities. The kinematic analysis reveals that some galaxies exhibit ordered rotation, with kinematic centres not always coincident with the luminous star-forming heads. Most systems show disturbed, asymmetric, or declining velocity profiles, while localized distortions near bright star-forming heads suggest that massive clumps influence the surrounding gas dynamics. We derive dynamical masses for the dominant clumps and investigate the mass--metallicity and size--metallicity relations. The clumps exhibit low metallicities consistent with the XMP regime and comparable to those observed in low-mass dwarf galaxies. Three galaxies show counter-rotating or kinematically decoupled ionised-gas components, indicating complex gas kinematics and possible external gas acquisition. Our sample is predominantly composed of isolated systems, with metal-poor star formation concentrated in compact head regions. These properties may reflect gas accretion through mergers, interactions, or the acquisition of metal-poor gas from the intergalactic medium and cosmic filaments. Internal processes such as outflows, gas mixing, recycling, and stochastic star formation may also contribute to the observed properties.
ER  -