Astro Lunch

Winter Quarter 2017

AU Mic’s Debris Disk Color Revealed Using Optical Coronagraphic Spectroscopy

PAB305
Speaker: Jamie Lomax (University of Washington)

I will present the first coronagraphic spectroscopy of the AU Mic debris disk system obtained with HST/STIS as part of GO-12512. Spectra of the system were taken by placing a long slit in the disk direction while blocking out the central star with an occulting bar. A naked star of similar spectral type was likewise observed for a PSF subtraction. This procedure results in a two dimensional spectrum as a function of disk position between 5200 and 10,200 angstroms for the system. I will report the results of these AU Mic spectra, which can be used to help determine the dust grain composition of the system by characterizing the disk’s color as a function of radial distance along the its midplane. In addition, I compare the spectra on either side of the disk in order to probe the presence of any compositional and structural asymmetries.  This reveals the dynamical perturbations and chemical processing occurring within the disk and traces the potential composition and architecture of any planetary bodies in the system.

Gas-rich Protoplanetary Disks within 100 pc: Observing Planet Formation at Close Range

PAB305
Speaker: Joel Kastner (RIT)

I will present an overview of the identification and investigation of the handful of “young solar system analogs” — star/disk systems — that lie within a mere ~100 pc of Earth. I describe advances in our understanding of protoplanetary disk structure and evolution enabled by these systems, with particular emphasis on the new discovery space that is now being opened by high-resolution imaging with ALMA as well as extreme AO cameras on large ground-based optical/IR telescopes.

Non-standard DM models and where to find them

PAB305
Speaker: Fabio Governato (University of Washington)

I will review a few recent results on theoretical models of galaxy formation in non standard DM models, with a focus on Warm Dark Matter and Self Interacting DM.

Benoit Côté

PAB305
Speaker: Benoit Côté (University of Victoria)

TBA

Autumn Quarter 2016

Massive Stars – Singles versus Couples

PAB356 (reading room)
Speaker: Claus Leitherer (STScI)

TBA

Wolf-Rayet Stars in the Local Group Galaxies

PAB356 (reading room)
Speaker: Kathryn Neugent (Northern Arizona University)

TBA

Massive White Dwarfs in Massive Binaries

PAB305
Speaker: Marina Orio (Padova/Wisconsin)

After briefly reviewing what is known and what we still need to know in order to correctly identify the supernovae Ia progenitors in different populations, I will talk about massive white dwarfs that are accreting mass in binary systems and are burning hydrogen in shell. I will review what we know about symbiotics and Be+white dwarf systems as possible progenitors of type Ia supernovae, and I will present new observational data about some of the hottest and massive white dwarf binaries in the Local Group.

Joe Burchett

PAB305
Speaker: Joe Burchett (UMass Amherst)

TBA

Jen Sobeck

PAB305
Speaker: Jen Sobeck (University of Virginia)

TBA

Ben Montet

PAB305
Speaker: Ben Montet (University of Chicago)

TBA

Study of AGN variability with the Palomar Transient Facility data

PAB305
Speaker: Neven Caplar (Institute for Astronomy, ETH Zurich)

TBA

Gwendolyn Eadie

PAB305
Speaker: Gwendolyn Eadie (McMaster University)

TBA

Spring Quarter 2016

Rotation and Activity in Low-mass Hyades and Praesepe Members, and the Implications for Gyrochronology

PAB356 (reading room)
Speaker: Stephanie Douglas (Columbia University)

TBA

Alireza Hojtat on lensing

Speaker: Alireza Hojtat

Key Processes of Galaxy Formation at High Redshift

PAB356 (reading room)
Speaker: Avishai Dekel (Hebrew University of Jerusalem)

TBA.

Winter Quarter 2016

Galactic winds on FIRE: the role of circumgalactic outflows in galaxy evolution

PAB356 (reading room)
Speaker: Sasha Muratov (UC San Diego)

Galactic winds blow through galaxies of all shapes and sizes, but they are particularly ubiquitous in high-redshift star-forming galaxies, where they may be driving galactic evolution by regulating the baryon cycle. Due to recent advances in the modeling of stellar feedback, cosmological simulations of galaxy formation can now generate galactic winds explicitly, while also matching many observed properties of galaxies at various epochs. We can therefore study simulated winds as an emergent phenomenon, and derive insights into galaxy evolution to compliment current observational knowledge. In my talk, I will discuss my progress in characterizing galactic outflows in the Feedback in Realistic Environments (FIRE) simulations. I will quantify the overall prevalence and intensity of galactic winds, their connection to physical galactic properties, and the observational implications of wind-driven evolution for galaxies and the circumgalactic medium.

APO General Update

PAB356 (reading room)
Speaker:

Please join us in the reading room on Tuesday Jan 12 at 4pm for a general meeting about APO, including new instrumentation on the 3.5m telescope, planning that is starting now for the 2.5m Sloan telescope in the 2020’s time frame (“After Sloan 4”), and current usage and availability of ARCSAT, the 0.5m photometric telescope.

You are particularly encouraged to participate if you have input about the new spectrograph (currently in planning stage) to replace DIS on the 3.5m. A committee is actively soliciting input from the users community for science requirements to determine design goals.

UW Ombud

PAB356 (reading room)
Speaker: Chuck Sloane

Intradepartment Research Talks

PAB356 (reading room)
Speaker: Various

Join us for 10 min talks by Chris Laws, Nicole Silvestri Kelly, Toby Smith, Oliver Fraser, Ana Larson, and Joe Huehnerhoff!

The GrayStar project: Moving computational stellar astrophysics into the Web browser

PAB356 (reading room)
Speaker: Ian Short (Saint Mary’s University, Halifax)

The goal of the GrayStar project is to turn any WWW browser running on any device into a didactic “teaching and learning” virtual star equipped with user-friendly input parameter knobs and instrumented with virtual observables and more advanced modeling outputs, so that stellar astronomy instructors can use physics education research (PER) methods in class. No special technical specifications are required of the user’s device, nor any special computational savviness on the part of the user. GrayStar3 is a physics-based general stellar atmosphere and spectral line modeling code written in JavaScript that displays its output in HTML. It is scientifically credible for pedagogical demonstration purposes, yet it adopts enough simplifying approximations to be almost instantaneously responsive and is suitable for classroom demonstration and lab-style homework projects. The HTML user interface is adaptable to be appropriate for a broad range of pedagogical levels, and there are more advanced physics modules that can be turned on to produce more realistic output and to address topics relevant at the introductory graduate level. GrayStar is publicly discoverable on-line and its accessibility as a WWW “activity” potentially “normalizes” the idea of scientific computational modeling and parameter inference. As JavaScript and HTML become more sophisticated, and as personal computational devices become more powerful, this approach may become increasingly important to the scientific education and research community. The application may be found here, and is most reliably responsive in the Chrome and Opera WWW browsers. Users are encouraged to download their own local installation and to modify it. Time permitting, I will address a recent extension of this idea, GrayStarServer, that performs on-demand spectrum synthesis on a server at Saint Mary’s and displays the result in the GrayStar client UI.

Dwarf galaxies and near-field cosmology in the APOSTLE simulations

PAB356 (reading room)
Speaker: Kyle Oman (University of Victoria)

TBA.

Intradepartment Research Talks (Grads)

PAB356 (reading room)
Speaker: Grads

10 min astro lunch talks by graduate students.

Fred Davies

Speaker: Matt McQuinn

The Fluctuating UV Background Across Cosmic Time

Intradepartment Research Talks (Grads)

PAB356 (reading room)
Speaker: Grads

10 min astro lunch talks by graduate students.

Cluster Cosmology: Models, Simulations and Reality?

PAB356 (reading room)
Speaker: Gus Evrard (University of Michigan)

TBA

Autumn Quarter 2015

Testing Asteroseismology with Red Giants in Eclipsing Binaries

PAB356 (reading room)
Speaker: Meredith Rawls (NMSU)

Oscillating stars in eclipsing binaries are powerful tools for testing stellar models because binarity allows for independent computation of physical stellar parameters. Thanks to advances in asteroseismology, red giants have become astrophysical laboratories for studying stellar evolution and probing the Milky Way. In this talk, I highlight an interesting pair of oscillating red giants in the eclipsing binary KIC 9246715, and I discuss work underway to characterize the 20 known red giants with eclipsing companions observed by Kepler. These are rapidly becoming some of the best-studied stars and an important benchmark for asteroseismology.

Astro Lunch

PAB356 (reading room)
Speaker: Various Faculty

This is the first of a series of astro lunches featuring short (10 minute) talks by the faculty in October. This event will contain talks by Julianne, Matt, Emily, Fabio, and Paula. See you there!

Rocky Planets and Rocks on Planets

PAB356 (reading room)
Speaker: Lauren Weiss (UC Berkeley)

I will discuss my work to determine the compositions of small planets.  The density-radius distribution of 72 exoplanets smaller than 4 Earth radii peaks at 1.5 Earth radii.  Planets smaller than 1.5 Earth radii usually increase in density with increasing planet radius, suggesting that planets up to 1.5 Earth radii can have rocky surfaces.  However, planets larger than 1.5 Earth radii typically decrease in density with increasing planet radius, suggesting that at around 1.5 Earth radii, planets begin to accrete volatile envelopes that reduce their bulk density. This trend is exemplified in two systems for which I present updated planet masses.  By simultaneously fitting radial velocities and transit timing variations with TTVFast, I determined that (1) Kepler-11 has six planets with volatile envelopes; and (2) Kepler-10 has one rocky planet, one planet with a volatile envelope, and one non-transiting planet candidate.  Finally, I will describe an instrument I am developing for topographic compositional mapping of rocks and ices on solar system worlds.

Astro Lunch (Faculty Research Talks)

PAB356 (reading room)
Speaker:

10 minute faculty research talks at noon in the reading room. Join us!

Astro Lunch (Postdoc/Researcher Talks)

PAB356 (reading room)
Speaker:

10 minute post-doc/research scientist research talks (+ 1 faculty member).

Astro Lunch (Postdoc/Researcher Talks)

PAB356 (reading room)
Speaker:

10 minute post-doc/research scientist research talks (+ 1 faculty member)

Astro Lunch (Postdoc/Researcher Talks)

PAB356 (reading room)
Speaker:

10 minute post-doc/research scientist research talks

Supermassive black hole formation in cosmological simulations

PAB356 (reading room)
Speaker: Melanie Habouzit (Institut d’Astrophysique de Paris)

TBA