Dartmouth Events

Physics & Astronomy Virtual Colloquium - David Alexander, Durham University

Title: "Why is color special? Identifying fundamental differences between red and blue quasars"

Friday, May 14, 2021
3:00pm – 4:00pm
Zoom: Email for link and password
Intended Audience(s): Public
Categories: Lectures & Seminars

Abstract:  The majority of quasars are blue in color, revealing a direct view of the accreting
supermassive black hole that powers these cosmic beasts. However, a
minority of the quasar population are optically red, almost certainly due
to the presence of obscuring dust along the line of sight. The standard
model postulates that red quasars are essentially blue quasars
viewed at such an angle that we don't directly see the quasar engine.
I will report on a systematic and controlled multi-wavelength experiment
where we identify a variety of fundamental differences between red and blue
quasars, in direct confrontation with the standard model. I will use our results to
demonstrate that red quasars likely represent a specific phase in the
evolution of quasars. I will briefly discuss how we will use future surveys,
such as DESI, to extend our investigations towards even more extreme
subsets of the quasar population to put together a complete picture
on the evolution of quasars.

For more information, contact:
Tressena Manning
603-646-2854

Events are free and open to the public unless otherwise noted.