UA Science

From left: Dennis Zaritsky, intensity map of hydrogen absorption in Milky Way halo (galactic coordinates), Huanian Zhang.

Neutral Hydrogen Permeating the Milky Way Halo

After combining hundreds of thousands of spectra of extragalactic objects, Steward Postdoc Huanian Zhang and Professor Dennis Zaritsky report the first detection of diffuse hydrogen wafting about in a vast halo surrounding the Milky Way. Such a halo had been postulated based on what astronomers knew about other galaxies, but never directly observed. The map of the H-alpha absorption across the areas of sky that were studied show a low, but consistent, level of absorption of light by hydrogen. You can read the UA press release HERE, and a WIRED UK article HERE. The preprint can be found HERE

Image courtesy of AAS.

New Quasars with Redshifts 5.3<z<5.7

A collaboration led by incoming Steward postdoc Jinyi Yang (Peking University, China and Steward Observatory, University of Arizona), and including Regents' Professor Xiaohui Fan, and Feige Wang, Ian McGreer, Richard Green, Minghao Yue, and Jiani Ding have found a significant number of new quasars in a redshift range, 5.3<z<5.7, that is difficult to probe with optical data alone. 

They used optical SDSS photometry combined with infrared photometry from several sources: UKIRT InfraRed Deep Sky Surveys - Large Area Survey (ULAS), VISTA Hemisphere Survey (VHS), and the WISE satellite (Wide Field Infrared Survey Explorer).  Candidates were followed up spectroscopically using Arizona's MMT and Bok telescopes, as...

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