NOAO >   Observing Info >   Approved Programs >   2017B-0811

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Program Information for 2017B-0811


PI: Kyoung-Soo Lee, Purdue U., soolee@purdue.edu
Address: Physics Department, 525 Northwestern Avenue, West Lafayette, Indiana 47907 United States

CoI: Yun Huang, Purdue U.
CoI: Rui Xue, Purdue U.

Title: First Comprehensive Characterization of Lya Escape Fraction

Abstract: As a tracer of the ionizing photons produced by massive young stars, redshifted Lya emission offers a window into the high-redshift universe. Even though our ability to identify and study high-redshift galaxies often critically rests on Lya line identification and progressively more so for higher-redshift and lower-luminosity galaxies, it is poorly understood how Lya photons propagate and eventually escape the galaxy. As a resonant line prone to scattering and easily absorbed by dust, the expectation is that the dynamical state can impact the likelihood of Lya photons' escape by controlling the modes of mergers, gas accretion, and feedback. We propose to elucidate the role of galaxies' dynamical state -- measured by morphology -- on the escape of Lya photons. A key missing piece in the existing measures has been to account for diffuse Lya emission extending out to 5-10 times the galaxy size, which can contain up to 90% of the integrated Lya flux. Utilizing a novel technique we developed, we will combine the data from multiple redshift samples thereby maximizing the statistical power to discern and fully characterize the Lya emission down to an exceedingly low surface brightness limit. This project will enable a first complete characterization of Lya emission in and around high-redshift galaxies by determining the true Lya escape fraction and by quantifying how the ratio of Lya flux emerging from the galaxy and diffuse halo varies across different morphological types.

Program Type: Purdue

Scheduled Nights:
Run 1 (2017B):  WIYN/ODI -- 2n on Jan 16 - Jan 19 2018


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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