气候变化领域集成服务门户(CCPortal): Neutral Gas Properties and Lyα Escape in Extreme Green Pea Galaxies

CCPortal

DOI	10.3847/1538-4357/ab08eb
	Neutral Gas Properties and Lyα Escape in Extreme Green Pea Galaxies
	McKinney J.H.; Jaskot A.E.; Oey M.S.; Yun M.S.; Dowd T.; Lowenthal J.D.
发表日期	2019
ISSN	0004637X
卷号	874 期号:1
英文摘要	Mechanisms regulating the escape of Lyα photons and ionizing radiation remain poorly understood. To study these processes, we analyze Very Large Array 21 cm observations of one Green Pea (GP), J160810+352809 (hereafter J1608), and Hubble Space Telescope Cosmic Origins Spectrograph (COS) spectra of 17 GP galaxies at . All are highly ionized: J1608 has the highest [O iii] λ5007/[O ii] λ3727 for star-forming galaxies in Sloan Digital Sky Survey, and the 17 GPs have [O iii]/[O ii] ≥ 6.6. We set an upper limit on J1608's H i mass of , near or below average compared to similar-mass dwarf galaxies. In the COS sample, eight GPs show Lyα absorption components, six of which also have Lyα emission. The H i column densities derived from Lyα absorption are high, cm -2 = 19-21, well above the LyC optically thick limit. Using low-ionization absorption lines, we measure covering fractions (f cov ) of 0.1-1 and find that f cov strongly anticorrelates with Lyα escape fraction. Low covering fractions may facilitate Lyα and LyC escape through dense neutral regions. GPs with f cov sim; 1 all have low neutral gas velocities, while GPs with lower f cov = 0.2-0.6 have a larger range of velocities. Conventional mechanical feedback may help establish low f cov in some cases, whereas other processes may be important for GPs with low velocities. Finally, we compare f cov with proposed indicators of LyC escape. Ionizing photon escape likely depends on a combination of neutral gas geometry and kinematics, complicating the use of emission-line diagnostics for identifying LyC emitters.. The American Astronomical Society. All rights reserved.
英文关键词	dark ages, reionization, first stars; galaxies: dwarf; galaxies: evolution; galaxies: ISM; galaxies: star clusters: general; galaxies: starburst
来源期刊	Astrophysical Journal
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/176461
作者单位	Department of Astronomy, University of Massachusetts, Amherst, MA 01003, United States; Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, United States; Chandra X-Ray Center, Cambridge, MA 02138, United States; Department of Astronomy, Smith College, Northampton, MA 01063, United States
推荐引用方式 GB/T 7714	McKinney J.H.,Jaskot A.E.,Oey M.S.,et al. Neutral Gas Properties and Lyα Escape in Extreme Green Pea Galaxies[J],2019,874(1).
APA	McKinney J.H.,Jaskot A.E.,Oey M.S.,Yun M.S.,Dowd T.,&Lowenthal J.D..(2019).Neutral Gas Properties and Lyα Escape in Extreme Green Pea Galaxies.Astrophysical Journal,874(1).
MLA	McKinney J.H.,et al."Neutral Gas Properties and Lyα Escape in Extreme Green Pea Galaxies".Astrophysical Journal 874.1(2019).