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Astrophysics Seminars


The CASS Astrophysics Seminar features world-class astrophysicists from around the world speaking on current topics of research. Presentations are aimed at the graduate and post-graduate level, but are open to the general public. CASS seminars take place on Wednesdays from 3:00 - 4:00 p.m. in 383 SERF (Marlar Seminar Room), unless otherwise noted. You can watch a live stream of the talk or prior talks at the CASS Seminar YouTube Channel. The seminar organizer is Prof. Karin Sandstrom.

Upcoming Seminars

October 16, 2019

 "Measuring the Epoch of Reionization with TIME"

Abigail Crites
Keck Institute for Space Science Postdoctoral Fellow

 I will discuss TIME, an instrument being developed to study the faint objects in our universe using line intensity mapping (LIM). TIME allows us to study the epoch of reionization, illuminating how the first astronomical objects ionized the neutral hydrogen in the universe. The TIME instrument is a mm-wavelength spectrometer spanning the frequency range of 200-300 GHz with 60 spectral pixels and 16 spatial pixels. TIME will measure redshifted [CII] emission at redshift 5 to 9 to probe the evolution of our universe over that epoch of reionization. TIME will also detect low-redshift CO fluctuations and map the cosmic history of molecular gas in the epoch of peak cosmic star formation from redshift 0.5 to 2. This new instrument and this emerging technique will allow us to provide complementary measurements to typical galaxy surveys and illuminate the history of our universe. TIME was recently installed on a 12m ALMA prototype antenna on Kitt Peak for an engineering test and will return for 3 seasons of science observations in Fall of 2020.

October 23, 2019

 "ERQs are the BOSS of quasar samples: the highest velocity [O III]
quasar outflows"

Serena Perrotta
Postdoctoral Scholar, CASS

 I investigate extremely red quasars (ERQs), a remarkable population of heavily reddened quasars at redshift z ∼ 2-3 that might be caught during a short-lived ‘blow-out’ phase of quasar/galaxy evolution. I performed a near-IR observational campaign using Keck/NIRSPEC, VLT/X-shooter, and Gemini/GNIRS to measure rest-frame optical spectra of 28 ERQs with median infrared luminosity 〈log L (erg/s)〉∼ 46.2. They exhibit the broadest and most blueshifted [OIII ] λ4959,5007 emission lines ever reported, with widths ranging between 2053 and 7227 km/s, and maximum outflow speeds up to 6702 km/s. ERQs on average have [OIII ] outflows velocities about three times larger than those of luminosity-matched blue quasar samples. This discrepancy can be explained by a strong correlation between [OIII] kinematics and i-W3 colour, and not by radio loudness, or higher Eddington ratios. I estimate for these objects that at least 3-5 per cent of their bolometric luminosity is being converted into the kinetic power of the observed wind. My results reveal that ERQs have the potential to strongly affect the evolution of host galaxies.

October 30, 2019

Travis Barman
Professor, Lunar & Planetary Lab
University of Arizona

November 6, 2019

Coral Wheeler
CASS Postdoctoral Scholar, UC President's Postdoctoral Fellow

November 13, 2019

 "Decoding Galaxy Formation Physics with the UniverseMachine"

Peter Behroozi
Assistant Professor, Department of Astronomy
University of Arizona

 I discuss new methods that allow computers to recover the underlying physics of galaxy formation using only galaxy observations and dark matter simulations, and show how these methods have already changed our understanding of galaxy formation physics (including why galaxies stop forming stars). Basic extensions to the same techniques allow constraining internal galaxy processes, including coevolution between galaxies and supermassive black holes as well as time delays for supernova / GRB progenitors. Finally, I discuss how these methods will benefit from the enormous amount of upcoming data in widefield (HETDEX, LSST, Euclid, WFIRST) and targeted (JWST, GMT) observations, as well as ways they can benefit observers, including making predictions for future telescopes (especially JWST) and testing which of many possible targeted observations would best constrain galaxy formation physics.

November 20, 2019

Norman Murray
Professor, Canadian Institute for Theoretical Astrophysics (CITA)
University of Toronto

December 4, 2019

Simeon Bird
Professor, Department of Physics and Astronomy
UC Riverside

December 11, 2019

K. Decker French
Hubble Fellow
Carnegie Observatories

Winter 2020

January 22, 2020

Rebecca Bernstein
Staff Astronomer
Carnegie Observatories

February 19, 2020

Manoj Kaplinghat
Professor of Physics & Astronomy
UC Irvine

February 26, 2020

Gabriela Canalizo
Professor, Department of Physics and Astronomy
UC Riverside