1. The Low-Redshift Lyman Continuum Survey: The Roles of Stellar Feedback and ISM Geometry in LyC Escape
- Author
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Flury, Sophia R., Jaskot, Anne E., Saldana-Lopez, Alberto, Oey, M. S., Chisholm, John, Amorín, Ricardo, Bait, Omkar, Borthakur, Sanchayeeta, Carr, Cody, Ferguson, Henry C., Giavalisco, Mauro, Hayes, Matthew, Heckman, Timothy, Henry, Alaina, Ji, Zhiyuan, Komarova, Lena, Leclercq, Floriane, Reste, Alexandra Le, McCandliss, Stephan, Marques-Chaves, Rui, Östlin, Göran, Pentericci, Laura, Ravindranath, Swara, Rutkowski, Michael, Scarlata, Claudia, Schaerer, Daniel, Thuan, Trinh, Trebitsch, Maxime, Vanzella, Eros, Verhamme, Anne, Wang, Bingjie, Worseck, Gábor, and Xu, Xinfeng
- Subjects
Astrophysics - Astrophysics of Galaxies ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
One of the fundamental questions of cosmology is the origin and mechanism(s) responsible for the reionization of the Universe beyond $z\sim6$. To address this question, many studies over the past decade have focused on local ($z\sim0.3$) galaxies which leak ionizing radiation (Lyman continuum or LyC). However, line-of-sight effects and data quality have prohibited deeper insight into the nature of LyC escape. To circumvent these limitations, we analyze stacks of a consolidated sample of {\it HST}/COS observations of the LyC in 89 galaxies at $z\sim0.3$. From fitting of the continuum, we obtain information about the underlying stellar populations and neutral ISM geometry. We find that most LyC non-detections are not leaking appreciable LyC ($f_{esc}^{\rm LyC}<1$\%) but also that exceptional cases point to spatial variations in the LyC escape fraction $f_{esc}^{\rm LyC}$. Stellar populations younger than 3 Myr lead to an increase in ionizing feedback, which in turn increases the isotropy of LyC escape. Moreover, mechanical feedback from supernovae in 8-10 Myr stellar populations is important for anisotropic gas distributions needed for LyC escape. While mechanical feedback is necessary for any LyC escape, high $f_{esc}^{\rm LyC}$ ($>5$\%) also requires a confluence of young stars and ionizing feedback. A two-stage burst of star formation could facilitate this optimal LyC escape scenario., Comment: Submitted to AAS publications, 42 pages, 25 figures
- Published
- 2024