|COOKIES: By using this website you agree that we can place Google Analytics Cookies on your device for performance monitoring.|
Illuminating the Dark Universe with quasar-induced Ly-alpha emission
If you have a question about this talk, please contact Martin Haehnelt.
Galaxy formation occurs along the densest part of the filamentary Intergalactic Medium where the gas can collapse and form stars. The proto-galactic phases preceding substantial star-formation are however unobservable – in emission – in most of the studies conducted so far and thus poorly constrained. Recent theoretical models have suggested that gas-rich, low-mass haloes at high redshift may have indeed very low or absent star formation, as a consequence of lower gas metallicity, H2 self-regulation effects or reduced cooling accretion due photoionization. These “dark” galaxies may represent an important gas baryonic reservoir for later star-formation in more massive systems and a crucial ingredient in order to reproduce the properties of current galaxy population. In this talk, I will present the result of a an ongoing, successful program that uses a new approach to directly detect and study these “dark” phases of galaxy formation: the key idea is to use an external ``source of illumination’’, a bright quasar, to light up with fluorescent Ly-alpha emission dark, proto- galactic clouds and dense streams around galaxies in a large cosmological volume. In the first part of the talk, I will discuss our pilot project based on deep narrow-band imaging on VLT /FORS centered on a z=2.4 hyper-luminous quasar: how we identified and characterized the physical properties of the first sample of high-redshift, “dark” galaxy candidates. In the second part of the talk, I will present the detection of fluorescent emission from the Circumgalactic Medium of star forming galaxies and very recent, spectacular results obtained with Keck/LRIS of the detection of hundred-kpc scale filaments surrounding bright quasars.
This talk is part of the Institute of Astronomy Galaxies Discussion Group series.
This talk is included in these lists:
Note that ex-directory lists are not shown.
Other listsCambridge University Amnesty International Public Understanding of Risk Ageing Research
Other talksThe 2016 Sleep Summit TBC GRAND ROUNDS Ethics of Big Data Workshop TBA Formal Materials RIG Seminar Art speak