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Investigating Quasar Outflows in Absorption and Emission


Serena Perotta (UC Riverside)

October 31, 2017 @ 12:00 PM - 1:00 PM

In the last decade, the potential impact of galaxy-scale outflows driven by quasars on their environment has become widely recognized. Quasars not only provide radiative feedback in the form of pressure and photo heating, they also affect the ionization state of the gas in and around the host galaxies. In this talk I show that there is strong evidence of a different ionization state close to the quasar along and across the line of sight. I have exploited the spectra of 100 quasars at emission redshift zem = 3.5 – 4.5 to construct a large sample of narrow absorption line (NAL) systems. The observations have been carried out with VLT/X shooter in the context of the XQ-100 Legacy Survey. I statistically study their physical properties and distribution on different scales. I also present results from stacking Lyman alpha forest absorbers in the XQ-100 sample to look for metals signal at large velocity separation from the zem.

Finally, I briefly talk about the Extremely Red Quasars, a unique red-quasar population with exotic physical conditions. They are candidates to be young objects in a transition stage between dusty starbursts and unobscured blue quasars: the perfect laboratory where to study powerful outflows through their peculiar emission lines.