Events

Light-driven Molecular Transformations Captured by Ultrafast Spectroscopy
Dr. Chavdar Slavov, Assistant Professor, Department of Chemistry
University of South Florida

Femtosecond time-resolved spectroscopy reveals the excited-state pathways and chromophore dynamics that transform light absorption into photochemical and biological function. Using phytochromes, I will illustrate how the protein environment controls chromophore isomerization, which in turn initiates structural changes that regulate biological signaling.

Altermagnets: A New Technologically Relevant Class of Quantum Magnets
Daniel Agterberg
Professor, University of Wisconsin-Milwaukee

Magnetism underpins much of our current information technology. It also derives purely from quantum mechanics. Traditionally, discussion emphasizes two classes of magnets: usual ferromagnets, which underly data storage devices, and antiferromagnets, in which magnetic moments adopt an up-down structural motif. Recently, a new class of magnets, altermagnets, has generated tremendous interest. This class mixes properties of ferromagnets and antiferromagnets in a way that is promising for future applications.

From Extreme Binary Stars to Self-Driving Cars
Dr. Tony Rodriguez
Data Scientist, Waymo LLC (formerly Harvard CfA)

Compact objects -- white dwarfs (WDs), neutron stars, and black holes -- are laboratories for studying extreme physics under conditions unable to be replicated on Earth. When located in binaries, it becomes possible to measure properties of compact objects such as magnetic field strength, temperature, and the effects of mass transfer from a companion. In this talk, I will describe recent advancements in our understanding of WD magnetism.

Solving Atomic Structures of Molecules and Nanoclusters Using Superfluid Helium Droplet Cooling and Laser Alignment
Wei Kong
Department Head & Professor, Department of Chemistry - Oregon State University

We are building a prototype experimental apparatus to determine the atomic structures of molecules and nanoclusters using electron diffraction. We use superfluid helium droplets for cooling, thereby achieving effective field-induced orientation and alignment of the sample species. Electron diffraction patterns from the chosen orientation can then be accumulated until a satisfactory signal-to-noise ratio can be obtained.

How Dark is Space?
Tod R. Lauer
Astronomer, NOIRLab

We used NASA’s New Horizons spacecraft to measure the cosmic optical background (COB) intensity integrated over 0.4 ≲ λ ≲ 0.9 μm. The survey comprises 16 high Galactic-latitude fields. Images were obtained with the LORRI camera when New Horizons was 57 AU distant from the Sun. As such, the sky intensity measurements were unaffected by zodiacal light, which strongly interferes with COB measurements attempted from the inner solar system. T he survey yields a highly significant detection (6.8σ) of the COB at 11.16 ± 1.65 (1.47 sys, 0.75 ran) nW m−2 sr−1 at the LORRI pivot wavelength of 0.608 μm. The estimated integrated intensity from background galaxies, 8.17 ± 1.18 nW m−2 sr−1, can account for the great majority of this signal. The rest of the COB signal is formally classified as anomalous intensity but is not significantly different from zero. The simplest interpretation is that the COB is completely due to galaxies.

Better Together: Combining the Strengths of Rubin, Euclid, and Roman for Time-domain Science and Cosmology
Charlotte Ward
Assistant Professor, Department of Astronomy and Astrophysics in the Eberly College of Sciences at Penn State

We have entered an exciting decade for survey science, with space-based surveys such as Euclid and Roman and ground-based surveys such as Rubin Observatory's Legacy Survey of Space and Time (LSST) providing overlapping imaging datasets across the optical and IR. LSST will identify thousands of tidal disruption events (TDEs) and millions of AGN and supernovae – including hundreds of gravitationally lensed supernovae (gLSNe) from which we can measure the Hubble Constant.