Past Events
| Event | Date | Summary |
| Astronomy Colloquium: Benne Holwerde | Thu. March 5th, 2020 3:00 pm-4:00 pm |
What can the Occult Do for You? Using overlapping galaxies to probe dust properties in galaxies Interstellar dust is still a dominant uncertainty in Astronomy, limiting precision in e.g., cosmological distance estimates and models of how light is re-processed within a galaxy. When a foreground galaxy serendipitously overlaps a more distant one, the latter backlights the dusty structures in the nearer foreground galaxy. Such an overlapping or occulting galaxy pair can be used to measure the distribution of dust in the closest galaxy with great accuracy. |
| Astronomy Colloquium: Luca Casagrande | Fri. February 28th, 2020 2:15 pm-3:30 pm |
Cool stars for Galactic archaeology Owing to their long life-times, cool stars can be regarded as fossils from different epochs of the formation and evolution of the Galaxy. To write this narrative, accurate stellar parameters are vital. Here I focus on the importance of photometry to derive stellar parameters, as well as to assess selection functions, and target selection effects in present-day surveys. Cool stars are also characterised by solar like-oscillations, which allow us to determine stellar properties that otherwise we would not have access to. The study of solar-like oscillations is a powerful new tool to investigate stellar populations across the Galaxy, |
| Astronomy Colloquium: Steve Rodney | Fri. February 21st, 2020 2:15 pm-3:30 pm |
Stellar Explosions and Cosmic Lenses A new field of study is opening in astrophysics, at the intersection of strong gravitational lensing and stellar transient science. Very rarely a supernova (SN) or other stellar transient happens to appear in nearly perfect alignment behind a foreground galaxy or cluster. In this case the general relativistic effect of gravitational lensing may boost the transient’s apparent brightness by several magnitudes and cause it to appear as multiple images on the sky. Only a handful of these strongly-lensed transients have been observed to date, but the sample will soon grow to hundreds with upcoming wide-field surveys like LSST and WFIRST. |
| Astronomy Colloquium: Danielle Berg | Fri. February 14th, 2020 2:15 pm-3:30 pm |
Bridging Galaxy Evolution Across Cosmic Time: Tracing the Interplay Between Massive Stars and Their Surrounding Gas with Spectroscopy The first stars and galaxies initiated the epoch of reionization (EoR) and provided the seeds from which all galaxy evolution grew. Knowledge of the properties of these galaxies are needed to understand ionizing photon production and escape, and will provide the crucial missing link needed to weave a coherent picture of galaxy evolution. I will present several programs that are establishing the needed framework to interpret galaxies from z~0‒10, bridging the present-day and early universe. |
| Astronomy Colloquium: Tabetha Boyajian | Thu. December 5th, 2019 3:00 pm-4:00 pm |
Planet Hunters and the Most Mysterious Star in the Galaxy (Note: this is a “research-grade” version of Prof Boyajian’s public talk at the Cleveland Museum of Natural History later in the evening.) Abstract: The NASA Kepler Mission provided 4 year long, ultra-precise light curves for over 150,000 stars with a primary science goal of finding transiting planets. In Kepler’s field of view was KIC 8462852, a star citizen scientists identified to have unusual brightness variations. This otherwise seemingly normal F star underwent erratic and completely unpredictable dips in flux ranging from <1% to more than 20%, |
| Joint Astronomy and EEPS Colloquium: Emilie Dunham | Thu. October 24th, 2019 3:00 pm-4:00 pm |
Meteoritic Implications for the Galactic Environment of Solar System Formation Short-lived radionuclides (SLRs) once present in the solar nebula can be used to probe the Solar System’s galactic formation environment. Isotopic analyses reveal that the first solids formed in the Solar System, calcium- and aluminum-rich inclusions (CAIs) in chondritic meteorites, formed with the live SLRs 10Be (t1/2 = 1.4 Myr) and 26Al (t1/2 = 0.7 Myr). Beryllium-10 is produced when high-energy ions, solar energetic particles or galactic cosmic rays (GCRs), spall nuclei in gas or dust. The most likely source of Solar System 10Be is inheritance of GCR-irradiated protosolar molecular cloud material, Continue reading… Joint Astronomy and EEPS Colloquium: Emilie Dunham |
| Astronomy Colloquium: Sabine Hossenfelder | Thu. October 17th, 2019 3:00 pm-4:00 pm |
Dark matter – or what? In this talk I will explain (a) what observations speak for the hypothesis of dark matter, (b) what observations speak for the hypothesis of modified gravity, and (c) why it is a mistake to insist that either hypothesis on its own must explain all the available data. The right explanation, I will argue, is instead a suitable combination of dark matter and modified gravity, which can be realized by the idea that dark matter has a superfluid phase. |
| Joint Astronomy and EEPS Colloquium: Peter James | Thu. October 3rd, 2019 3:00 pm-4:00 pm |
The crust of Mercury, as seen by the MESSENGER spacecraft NASA’s MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft was the first craft to orbit Mercury, our solar system’s innermost planet. The MESSENGER mission team consisted of scientists from around the globe—including some from CWRU—and the data returned by MESSENGER revealed a planet unlike any other in our solar system. Mercury’s metal core is approximately 80% of the diameter of the planet, so Mercury is a type of a predominantly metal world that be orbiting around other stars. Mercury has a history of pervasive volcanic eruptions (no longer active) with distinct geochemical terranes, Continue reading… Joint Astronomy and EEPS Colloquium: Peter James |
| Astronomy Colloquium: K.S. Dwarakanath | Thu. September 19th, 2019 3:00 pm-4:00 pm |
Diffuse Radio Emission in Galaxy Clusters Galaxy clusters are some of the largest gravitationally bound structures in the Universe. Satellite observations during the early 70’s discovered diffuse X-ray emitting hot gas in the clusters. Cluster-wide non-thermal radio emission was also subsequently discovered in some of the X-ray bright clusters and has been a topic of multi-wavelength studies ever since. This radio emission, which is not associated with any of the cluster galaxies, arises due to relativistic particles and magnetic fields in the Intra Cluster Medium and is extended over millions of light years, |
| Astronomy Colloquium: Narendranath Patra | Thu. September 12th, 2019 3:00 pm-4:00 pm |
The missing satellite problem and the dark galaxies Though the Lambda-CDM model of cosmology has been immensely successful in explaining the observable universe at large scales, several inconsistencies yet persist between its predictions and observations in smaller scales. The `missing satellite’ problem is one of the significant ones. The number of predicted small galaxies within the virial radii of massive galaxies is found to be an order of magnitudes higher than what is observed as luminous satellites of such galaxies. Out of many proposed solutions to this problem, the ‘HVC-minihalo’ |