ASD Colloquium Series - Spring 2025
ASD Colloquium Series - Spring 2025
The Astrophysics Science Division colloquia occur on Tuesdays at 3:45 pm in a Hybrid format. For in person attendees, the colloquia will be held in building 34, room W150 (unless otherwise noted), with an opportunity to meet the speaker at 3:30 pm. Virtual attendees should use connection information in the calendar invites.
Below is the list of scheduled talks for this period. Confirmed speakers are shown in bold face, while tentatively scheduled speakers are listed in normal face.
Schedules from past colloquium seasons are available.
Contact: Scott C. Noble
| January | |
|---|---|
| Jan 7 | Binary Black Hole Formation: A Multimessenger, Multiband Puzzle Katelyn Breivik (Carnegie Mellon University) |
| Jan 14 | No Colloquium - Winter AAS Meeting |
| Jan 21 | No Colloquium - MLK/Inaugaration Day |
| Jan 28 | TBD |
| February | |
| Feb 4 | Special Location: B34, W130 Precision interferometry: Towards exo-Earth imaging and 30m-class telescopes Steve Ertel (Steward Observatory and the Large Binocular Telescope Observatory) |
| Feb 11 | Standing Out from The Crowd: Finding Supermassive Black-hole Binaries in Gravity & Light Stephen Taylor (Vanderbilt University) |
| Feb 18 | No Colloquium - Washington's Birthday |
| Feb 25 | TBD Krista Lynne Smith (Texas A&M University, College Station, USA) |
| March | |
| Mar 4 | TBD |
| Mar 11 | TBD Renee Ludlum (Wayne State U) |
| Mar 18 | TBD Klaus Pontoppidan (STScI/JPL) |
| Mar 25 | TBD Alexander Cooper (Oxford) |
| April | |
| Apr 1 | TBD Anna Ho (Cornell) |
| Apr 8 | TBD |
| Apr 15 | TBD Chris Richardson (Elon U) |
| Apr 22 | TBD Grace Telford (Princeton) |
| Apr 29 | TBD Julia Roman-Duval (STScI) |
May |
| May 6 | TBD Nico Cappelluti (U Miami) |
| May 13 | TBD |
| May 20 | TBD Chiara Mingarelli (Yale) |
| May 27 | No Colloquium - Memorial Day |
| June | |
| June 3 | TBD Margaret Lazzarini CSU-LA) |
Abstract
Binary star populations play a pivotal role in nearly all subfields of astronomy and cosmology, yet the quantitative details of how they evolve are still poorly described. This is due both to a wide array of uncertain physical interaction processes like mass exchange and supernova explosions that can work in compounding ways and a lack of large data sets that contain binary populations across different evolutionary phases. In this talk, I'll review how binary-star interactions shape stellar populations hosting black holes and introduce recent and upcoming gravitational wave and electromagnetic survey data releases that can be used to constrain models for binary evolution. I'll finish with a discussion of the discovery of a new population of compact objects in binaries with stellar companions made by the Gaia satellite that offer a unique window into compact object formation.
Abstract
Compared to filled-aperture telescopes, astronomical optical long-baseline interferometry typically provides higher angular resolution and higher-precision spatial measurements at the cost of fidelity, dynamic range, and consequently contrast of reconstructed images. I use the term precision interferometry to refer to efforts of overcoming this limitation through more precise measurements of the classical interferometric observables (visibilities and closure phases) or though circumventing them altogether using nulling or Fizeau (imaging) interferometry. Over the past almost two decades, these efforts have enabled the spatially resolved observations of the habitable zones and closer in of planetary systems with a sensitivity to detect circumstellar, exozodiacal dust. This dust poses both an opportunity to study the architectures and dynamics of planetary systems near their habitable zones and a potential obstacle to directly imaging rocky, habitable-zone planets. It's study is thus crucial for enabling and preparing for a future exo-Earth imaging mission such as the Habitable Worlds Observatory. I will review our work on exozodiacal dust with the Large Binocular Telescope Interferometer (LBTI) and the Very Large Telescope Interferometer (VLTI). I will further present our efforts to enable high-fidelity imaging at the angular resolution of a 23m telescope with the LBTI for general astronomical observations. This work makes the LBTI a critical pathfinder for future 30m-class telescopes. Both exo-Earth imaging and the completion and exploitation of 30m-class telescopes are major priorities of the US community as outlined in the National Academy's Astro2020 Decadal Survey. I will then close the loop and conclude my talk by outlining our efforts to obtain the first direct-imaging detection of a rocky, habitable-zone planet around a nearby, Sun-like star with the LBTI.
Abstract
The Universe is thrumming with gravitational waves. June 2023 brought the first evidence for an all-sky background of nanohertz-frequency gravitational waves, discovered by collaborations including the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) and groups in Europe, Australia, India, and China. This was an endeavor decades in the making, requiring painstakingly precise timing observations of scores of millisecond pulsars across the Milky Way using flagship radio telescopes. While the results from separate groups are consistent with one another—and the leading interpretation of a cosmic population of supermassive black-hole binaries as the source—the observations provoke many new questions. Do the results imply a population of binaries more massive than expected? What are the observational milestones as the first resolvable massive black-hole binary signals come into focus? Can we link these signals to host galaxies and leverage electromagnetic counterparts to do multi-messenger astronomy with massive black holes? In this talk, I will chart the path to discovery, reflect on what we have learned during our year+ since our announcement, and explore the exciting opportunities ahead—including the role of next-generation instruments in expanding our pulsar network to explore the low-frequency gravitational-wave and supermassive binary black-hole landscape.