Astrophysics

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Suvi Gezari: Hungry Black Holes

April 24, 2018, 4:00 PM - 5:00 PM

Title: Hungry Black Holes

Speaker: Suvi Gezari, University of Maryland

Host: Giacomo Terreran

Abstract:

We are entering an era of increasingly powerful wide-field optical imaging surveys that are transforming the study of the variable night sky. I will highlight the capability of time domain observations to probe supermassive black holes (SMBHs) lurking in the centers of galaxies by catching them light up in the act of feeding on stars and gas. Watching how these “hungry” black holes digest their meals can reveal their mass, spin, and binarity; the fundamental parameters of an astrophysical black hole. I will present results from our systematic studies of nuclear transients with the Pan-STARRS1, iPTF, and ZTF surveys, and conclude with a discussion of the exciting potential of the LSST to map the demographics of SMBHs over cosmic time.

 

Keywords: Physics, Astronomy, Astrophysics


Title: Momentum-driven winds from radiatively efficient black hole accretion and their impact on galaxy properties

Speaker: Rachel Somerville, Rutgers University

Host: Sarah Wellons

Abstract: Accretion onto supermassive black holes in galactic nuclei can produce energetic radiation and jets. The impact of these physical processes (collectively referred to as "AGN Feedback") on galaxies and the circum- and intergalactic gas is a central topic of investigation in galaxy formation and cosmology. Many state-of-the-art cosmological simulations of galaxy formation and evolution have focussed on the "jet mode" of AGN feedback, and have largely neglected the momentum that may be imparted to gas via radiation pressure on gas and dust. Observations indicate that most or perhaps even all active galaxies may contain high-velocity outflows, but there is an ongoing debate about the mass-loading factors and overall impact of these outflows on large scales. In this talk I will present results from a recent suite of high-resolution "zoom in" cosmological hydrodynamic simulations in which we model both thermal and momentum feedback from radiatively efficient accretion onto supermassive black holes in massive galaxies. We carry out an analysis of gas and metal inflows and outflows in these simulations, and in a matched suite that is identical except that they do not include black holes and AGN feedback. I will discuss the properties of the winds driven by the combined effects of stars and black holes, and how they differ in the full and no-AGN simulation suites. In addition I will discuss the impact of these winds on observable properties of galaxies and the circumgalactic medium.

Keywords: Physics, Astronomy, Astrophysics


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Justin Crepp: TBA

May 8, 2018, 4:00 PM - 5:00 PM

Title: TBA

Speaker: Justin Crepp, University of Notre Dame

Host: Ben Nelson

Abstract: TBA

Keywords: Physics, Astronomy, Astrophysics


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Jason Tumlinson: TBA

May 15, 2018, 4:00 PM - 5:00 PM

Title: TBA

Speaker: Jason Tumlinson

Host: 

Abstract: TBA

Keywords: Physics, Astronomy, Astrophysics


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Charlie Conroy: TBA

May 22, 2018, 4:00 PM - 5:00 PM

Title: TBA

Speaker: Charlie Conroy, Harvard University

Host: Cliff Johnson

Abstract: TBA

Keywords: Physics, Astronomy, Astrophysics


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Ramesh Narayan: TBA

May 29, 2018, 4:00 PM - 5:00 PM

Title: TBA

Speaker: Ramesh Narayan, Harvard University

Host: Sasha Tchekhovskoy

Abstract: TBA

Keywords: Physics, Astronomy, Astrophysics


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CIERA Astronomer Evenings

August 31, 2018, 9:00 PM - 11:00 PM

CIERA Astronomer Evenings are special programs that take place on the last Friday of every month at Northwestern's Dearborn Observatory.

Look through the historic telescope and meet and talk with astronomers from CIERA, Northwestern's Center for Interdisciplinary Exploration and Research in Astrophysics!

Each month, different experts will be available to answer your astronomy and astrophysics questions. These evenings begin with a 10-minute introduction to a topic in astronomy, followed by an open Q&A session and fun, interactive demonstrations.

The talks are free and open to all!