NOAO >   Observing Info >   Approved Programs >   2013B-0306

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Proposal Information for 2013B-0306


PI: Sebastiano Cantalupo, UC Santa Cruz, cantal@ucolick.org
Address: Astronomy and Astrophysics Board of Study, Natural Sciences II, Santa Cruz, CA, 95064, USA

CoI: Fabrizio Arrigoni Battaia, Max Planck Institut fuer Astronomie
CoI: Joseph F. Hennawi, Max Planck Institut fuer Astronomie
CoI: Jason X. Prochaska, UC Santa Cruz

Title: Deep Lyman-alpha Imaging of Luminous z 2 Quasars: Testing the Cold Accretion Paradigm

Abstract: The current galaxy formation paradigm postulates that a significant amount of gas accretes onto galaxies from the IGM in a cold T 10^4 K phase, and many have argued that this gas should be detectable in diffuse Ly-alpha emission. We have discovered the largest Ly-alpha nebulosities known around two luminous QSOs at z 2. With sizes of the order of 500 kpc, they represent the first images of gas extending into the IGM, and could be the first direct detection of this cold accretion. Our limited statistics suggest 10-30% of QSOs could exhibit similar giant nebulosities, which have not yet been uncovered because previous searches lacked the required sensitivity. We propose to conduct deep GMOS-S narrow-band imaging of 5 QSOs at z 2 using our custom-made filter Lya395, which has already been commissioned at Gemini South. These observations will enable the first deep statistical census of extended Ly-alpha emission around QSOs, which will test the predictions of our galaxy formation paradigm. Additionally, the same dataset will allow us to continue our statistical survey for QSO-powered fluorescent Ly-alpha emission from proto-galactic clouds, or so called `dark-galaxies', around the QSOs. We will make an end-to-end comparison of the proposed observations to our state-of-the-art cosmological radiative transfer simulations.


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