Astronomy Colloquium
Colloquia are held every Wednesday during the academic year at 4pm in the Cahill Hameetman auditorium. Wine and cheese will be served in the Cahill Foyer from 5-5:30pm.
ASTRONOMY COLLOQUIUM
Following the success of our lightning talk colloquium last year, several incoming Astronomy postdocs and research scientists will give lightning presentations and introduce themselves and their research to the department.
ASTRONOMY COLLOQUIUM
Explosive growth in digital technology has created a radio interferometry renaissance, enabling current and upcoming astronomical facilities such as ALMA, ngVLA, SKA, and DSA-2000. These same breakthroughs led to the Event Horizon Telescope (EHT), a global very-long-baseline interferometry (VLBI) network operating at 230 GHz that recently produced the first images of black holes. I will summarize our major EHT discoveries, which have led to new insights in black hole accretion and jet formation. I will also describe ongoing efforts to develop the Black Hole Explorer (BHEX), a mission that will produce the sharpest images in the history of astronomy by extending the EHT to space. Submillimeter space-VLBI will provide access to the bright and narrow "photon ring" that is predicted to exist in images of black holes, produced from light that has orbited the black hole before escaping. In addition to studying the properties of the nearby supermassive black holes M87* and Sgr A*, BHEX will measure the properties of dozens of additional supermassive black holes and will connect them to their relativistic jets, elucidating the power source for the brightest and most efficient engines in the universe.
ASTRONOMY COLLOQUIUM
The high-redshift transient universe has been an unexplored field of astrophysics due to the vast amount of resources required to discover supernovae (SNe) at z>1. Even with the Hubble Space Telescope (HST), discoveries of the most distant stellar explosions have been restricted to z~2, including with the aid of gravitational lensing. Spectroscopy is critical to both classification and characterization of high-redshift SNe, but it is even more difficult than imaging and has been limited to z~1.5. With the launch of the James Webb Space Telescope (JWST), we have entered a new era of high-redshift SN discovery and understanding. In a relatively short time JWST has expanded our view of the transient universe to z~5, including hundreds of SNe and dozens of rest-frame UV-IR spectra for transients reaching z=3.6. The JWST SN sample with both imaging and spectroscopy now includes the most distant Type Ia SNe (used for cosmological measurements) yet discovered, three strongly lensed SNe, and a wide variety of core-collapse SN sub-types from a previously unexplored phase of the transient universe. I will summarize the range of discoveries made in the first ~2 years of JWST observations, the constraints gleaned from these exciting new objects, and our ongoing efforts to build the first statistical samples of high-redshift SNe. Looking ahead, these SNe give us a glimpse at what we can expect from the upcoming Nancy Grace Roman Space Telescope, which will revolutionize the discovery of distant stellar explosions.