About Event

Thu 21 Apr 2022




Lyman-alpha (Lya) surveys are an important tool to constrain the timing and topology of reionization. However, ground-based Lya surveys are not effective at z>8 largely due to the increasing night sky background, and even at z~7 Lya surveys must conduct expensive spectroscopic follow-up of their Lya candidates to eliminate contamination. The Roman Space Telescope's ability to obtain deep near-infrared spectra over a wide field of view offers the opportunity to revolutionize this field. To investigate this further, we have simulated a deep multi-position-angle Roman WFI grism survey and tested our ability to recover z>7 Lya emitters. We show how a novel data cube search technique — CUBGRISM — originally developed for GALEX grism data can be applied to Roman grism data to produce a Lya flux-limited sample without the need for a continuum detection. Given our adopted reduction technique, we investigate the impact of altering the number of independent position angles and total exposure time. Our results indicate that a proposed deep Roman grism survey can achieve Lyalpha line depths comparable to the deepest z=7 narrow-band surveys, allowing us to study the evolution of Lya populations and infer the ionization state of the intergalactic medium at cosmic dawn.

Speaker: Isak Wold (GSFC)


The Roman Lecture Series is a monthly virtual lecture series focused on the scientific capabilities and technology of the Nancy Grace Roman Space Telescope, organized by Roman Mission partners.


Nancy Grace Roman Space Telescope insignia

The NASA Nancy Grace Roman Space Telescope is managed by NASA/GSFC with participation of STScI, Caltech/IPAC, and NASA/JPL

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