Department Calendar

Monday, March 19, 2018

Time Items
All day
 
2pm
"Dispatches from the sub-GeV Dark Matter Frontier"

"Dispatches from the sub-GeV Dark Matter Frontier"

Date: 
Mon, 03/19/2018 - 2:10pm
Location: 
Pupin Hall Theory Center, 8th Floor

Tien-Tien Yu

CERN

"Dispatches from the sub-GeV Dark Matter Frontier"

The sub-GeV dark matter mass range has received increased interest in the last several years, owing to the lack of any unambiguous signal of the canonical WIMP in the GeV-TeV mass range. The sub-GeV mass range is relatively unexplored due to the difficulty of detecting such light dark matter with traditional techniques. However, there have been recent experimental developments that finally make sub-GeV direct detection viable. I will discuss some of the theoretical principles and strategies to explore sub-GeV dark matter candidates, as well as some current and proposed experimental techniques. I will focus predominantly on semiconductor targets, such as the new SENSEI experiment which utilizes silicon CCDs, and demonstrate the potential for exploring the eV-GeV dark matter mass range in the near future. 
 
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03/19/2018 - 2:10pm
 
4pm
"Life after Death: Transient Emission from Compact Objects in Galactic Nuclei"

"Life after Death: Transient Emission from Compact Objects in Galactic Nuclei"

Date: 
Mon, 03/19/2018 - 4:15pm
Location: 
428 Pupin Hall

Nicholas Stone

Columbia University

"Life after Death: Transient Emission from Compact Objects in Galactic Nuclei"

In most regions of the Universe, stellar orbits have enormous mean free paths, and the timescale for a strong two-body encounter exceeds a Hubble time.  However, in dense stellar systems, such as open, globular, and nuclear star clusters, close encounters between stars and/or compact objects are frequent, and may lead to the production of transient electromagnetic or gravitational-wave radiation.  I will present my research showing how the densest stellar systems in the Universe — galactic nuclei — are dynamical factories that manufacture transient sources such as X-ray binaries, tidal disruption events, and LIGO-band black hole mergers.  I will discuss my past and ongoing work to understand the transient electromagnetic and gravitational radiation from these dynamically assembled systems, focusing especially on ways in which time domain astronomy can probe general relativity.

About the speaker

Nicholas Stone is a NASA Einstein Fellow (2015-2018) at Columbia University, where he works on a variety of topics in theoretical astrophysics. Nicholas' primary collaborators at Columbia are Professors Brian Metzger, Jerry Ostriker, and Zoltan Haiman. Prior to this Nicholas worked as a postdoc at Columbia for two years. He received his PhD in Astronomy and Astrophysics from the Harvard Astronomy department in May 2013. At Harvard, Nicholas was advised by Professor Avi Loeb. Together they worked mainly on the tidal disruption of stars by supermassive black holes. In 2008, Nicholas graduated from from Cornell University with a triple major in Physics, Mathematics, and Economics.  From 2000-2004, Nicholas was a student at Montgomery Blair High School.

More details can be found here.

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03/19/2018 - 4:15pm
 
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