2017 - 2018 Astro Seminar Schedule

DateEvent TypeSpeakerTitle
09/08/2017Astro SeminarMarcel SchmittfullFundamental physics from the nonlinear Universe [ + Description ]
09/15/2017Astro SeminarNicholas BattagliaLarge-Scale Structure Information Encoded in CMB Photons [ + Description ]
09/22/2017Astro SeminarVivian PoulinCosmological signatures of exotic electromagnetic energy injection [ + Description ]
09/29/2017Astro SeminarTjitske StarkenburgThe diverse history of counterrotating galaxies [ + Description ]
10/06/2017Astro SeminarMansi KasliwalThe Dynamic Infrared Sky [ + Description ]
10/20/2017Astro SeminarJulie ComerfordAGN Fueling and Feedback in Galaxies [ + Description ]
10/27/2017Astro SeminarRenee HlozekNew cosmology with small-scale CMB data: ultra light dark matter, isocurvature and cosmic voids [ + Description ]
11/03/2017Astro SeminarJames PeeblesA Tale of Two Theories: Missing Mass in 1980 and Galaxy Formation Today [ + Description ]
11/10/2017Astro SeminarMatias ZaldarriagaThe spin of the black holes detected by LIGO [ + Description ]
11/17/2017Astro SeminarSarah PearsonThe Milky Way’s Galactic bar can punch holes in stellar streams [ -- Description ]

Description: As clusters of stars orbit our own Milky Way, a gravitational tidal interaction unfolds and the clusters tear apart into distinct morphological and kinematic structures. From our detailed understanding of gravity, the distribution and motion of these stellar structures enable us to work backwards in time and thereby study our Milky Way's past and evolution. Palomar 5 (Pal 5) is an old globular cluster orbiting our Galaxy, while disrupting into thin leading and trailing stellar arms. In this talk, I will show that a previous encounter between the Pal 5 stellar stream and the Milky Way’s Galactic bar has punched a hole in the stream which can explain why the leading arm of Pal 5 appears to be a lot shorter than the trailing arm. The discovery that the bar can punch holes in stellar streams has important implications for near-field cosmology as the Milky Way should be filled with dark matter subhalos of various sizes according to the cold dark matter paradigm. One proposed method to detect subhalos is to search for them through disturbances in the structure of stellar streams, as dark subhalos should create gaps if they pass through or close by stellar streams. My work implies that caution should be applied before interpreting stream gaps as evidence for dark matter subhalos. Additionally, I will demonstrate how the Galactic bar’s interaction with the Palomar 5 stream provides an intriguing methodology for studying our Milky Way’s Galactic bar in more detail. (11:00 AM, 726 Broadway, 940, CCPP Seminar)
12/01/2017Astro SeminarVera GluscevicTBA (Theoretical Cosmology) [ + Description ]
12/08/2017Astro SeminarIlsedore CleevesTBA (planetary astronomy) [ + Description ]
01/19/2018Astro Seminar[none]No seminar this week; competing event at Flatiron CCA [ + Description ]
02/09/2018Astro SeminarJackie FahertyTBA (low-mass stars) [ + Description ]
04/13/2018Astro SeminarChris HaywardTBA (galaxy formation) [ + Description ]