Events List

DateEvent TypeSpeaker
03/03/2025CCPP Brown BagRoman Scoccimarro [ + ]
03/04/2025Astro SeminarJJ Zanazzi [ + ]
03/05/2025HEP SeminarGiorgio Gratta [ + ]
03/06/2025Astro SeminarJanosz Dewberry [ + ]
03/06/2025Physics Dept ColloquiumGiorgio Gratta [ + ]
03/07/2025Oral DefenseCara Giovanetti [ + ]
03/07/2025Hep-Th Discussion SessionCalkins [ + ]
03/10/2025CCPP Brown BagJesse Liu [ + ]
03/11/2025Astro SeminarRichard Anantua [ -- ]

Title: A Message from the Horizon Scale by EHT: Deciphering Observational Signatures of Sgr A* and M87*
Abstract: With some of the highest resolution images in astronomy, the Event Horizon Telescope has ushered in an age of horizon-scale imaging of supermassive black holes– our most direct probe of plasma astrophysics in strong gravity and the modern physics pillar of general relativity. With the first black hole images taken for the giant elliptical galaxy M87 and in our own Galactic Center at Sgr A*, theoretical models varying plasma magnetization and content, emission processes and black hole spin among others have revealed striking similarities and differences between astrophysical sources and general relativistic magnetohydrodynamics (GRMHD) simulations. In this investigation, models of magnetized plasma in the jet (or outflow)/accretion flow/black hole (JAB) system Sagittarius A* based on turbulent heating and deviations from the equipartition of particle and magnetic energies are input into a High Accuracy Relativistic Magnetohydrodynamics (HARM) simulation. Spectra, movies and light curves simulating hourly timescales show that these models aggregate into four quasi-stationary types: 1.) thin, asymmetric photon ring with best fit spectrum; 2.) coronal boundary layer with thin photon ring and steep spectrum; 3.) thick photon ring with flat spectrum; and 4.) extended outflow with low frequency spectral knee. For M87, a jet model based on a force-free flow in a HARM jet simulation is used to generate Stokes maps at Very Long Baseline Array (VLBA, 43 GHz) and Event Horizon Telescope (EHT, 230 GHz) scales. Positrons are also incorporated into the general relativistic ray tracer IPOLE combined with turbulent heating models for M87 to display positron effects on GRMHD simulations varying plasma content from ionic (e-p) to pair (e-e+), showing stark differences in polarization signatures between standard and normal evolution (SANE) and magnetically arrested disk (MAD) accretion modes due to Faraday effects. The cleanest observational signature in the MAD Stokes maps is the vanishing of circular polarization for increasing positron content (particularly for times when flux eruptions are prominent) and for SANE rapidly varying electric vector polarization angles with changing positron content. The inclusion of electrons, positrons and protons in our radiative transfer pipeline thus provides a powerful probe of the composition of JAB systems-- and helps set the stage for time-dependent analysis in black hole movies. (2:00 PM - 3:15 PM, 726 Broadway, 940, CCPP Seminar)
03/11/2025office hoursMathew Calkins [ + ]
03/12/2025HEP Journal Club [ + ]
03/12/2025HEP SeminarJunwu Huang [ + ]
03/12/2025office hoursMathew Calkins [ + ]
03/13/2025Physics Dept ColloquiumJacob Barandes [ + ]
03/14/2025Hep-Th Discussion SessionCalkins [ + ]
03/17/2025CCPP Brown BagAnthony Pullen [ + ]
03/18/2025Informal HEP TalkTony Zhou (host) [ + ]
03/18/2025Astro SeminarCarol Cuesta Lazaro [ + ]
03/19/2025HEP Journal Club [ + ]
03/19/2025HEP SeminarDaniel Harlow [ + ]
03/21/2025Informal HEP TalkTianli Wang [ + ]
03/21/2025Hep-Th Discussion SessionCalkins [ + ]
03/24/2025Holiday [ + ]
03/24/2025OtherRhine Samajdar [ + ]
03/25/2025Holiday [ + ]
03/26/2025Holiday [ + ]
03/27/2025Holiday [ + ]
03/28/2025Holiday [ + ]
03/28/2025Hep-Th Discussion SessionCalkins [ + ]
03/31/2025Informal HEP TalkAurelio Amerio [ + ]
03/31/2025Informal HEP TalkWilliam Pannell [ + ]
04/01/2025Astro SeminarBart Ripperda [ + ]
04/02/2025HEP Journal Club [ + ]
04/02/2025HEP SeminarCsaba Csaki [ + ]
04/03/2025Physics Dept ColloquiumAlessandra Buonanno [ + ]
04/04/2025Hep-Th Discussion SessionCalkins [ + ]
04/07/2025Special SeminarDalimil Mazac [ + ]
04/09/2025HEP Journal Club [ + ]
04/09/2025HEP SeminarLorenzo Ricci [ + ]
04/09/2025Cosmic Happy HourCammie Norton [ + ]
04/10/2025Physics Dept ColloquiumJesse Thaler [ + ]
04/11/2025Hep-Th Discussion SessionCalkins [ + ]
04/15/2025Astro SeminarJulien Lavalle [ + ]
04/16/2025HEP Journal Club [ + ]
04/16/2025HEP SeminarMichael Baker [ + ]
04/18/2025Hep-Th Discussion SessionCalkins [ + ]
04/21/2025CCPP Brown BagMarius Kongsore [ + ]
04/21/2025Informal HEP TalkNat Levine [ + ]
04/22/2025Astro SeminarGabriela Sato-Polito [ + ]
04/23/2025HEP Journal Club [ + ]
04/23/2025HEP SeminarGiovanni Villadoro [ + ]
04/25/2025Hep-Th Discussion SessionCalkins [ + ]
04/28/2025CCPP Brown BagMarcus DuPont [ + ]
04/29/2025Astro SeminarRisa Wechsler [ + ]
04/30/2025HEP SeminarDan Green [ + ]
04/30/2025HEP Journal Club [ + ]
05/02/2025Hep-Th Discussion SessionCalkins [ + ]
05/06/2025Astro SeminarTetyana Pitik [ + ]
05/07/2025HEP Journal Club [ + ]
05/07/2025HEP SeminarHowie Haber [ + ]
05/07/2025HEP SeminarHowie Haber [ + ]
05/09/2025Hep-Th Discussion SessionCalkins [ + ]
05/14/2025HEP Journal Club [ + ]