Calendar

May
12
Thu
Colloquium PhD Defense: Kenz Arraki
May 12 @ 3:00 pm – 4:00 pm
Colloquium PhD Defense: Kenz Arraki @ Dominici106

Evolution of Dwarf Galaxy Properties in Local Group Environments

Kenz Arraki, NMSU

Sep
19
Mon
Pizza Lunch: Reta Beebe
Sep 19 @ 12:30 pm – 1:30 pm
Pizza Lunch: Reta Beebe @ AY 119

Title: JUNO

Reta Beebe

A .pdf of the talk can be found here.

 

 

Sep
20
Tue
Colloquium Thesis Proposal: Ethan Dederick
Sep 20 @ 3:00 pm – 4:00 pm
Colloquium Thesis Proposal: Ethan Dederick @ Science Hall 310

Utilizing Planetary Oscillations to Constrain the Interior Structure of the Jovian Planets

Ethan Dederick

Seismology has been the premier tool of study for understanding the
interior structure of the Earth, the Sun, and even other stars. Yet in this
thesis proposal, we wish to utilize these tools to understand the interior
structure of the Jovian planets, Saturn in particular. Recent observations
of spiral density structures in Saturn’s rings caused by its oscillations
have provided insight into which modes exist within Saturn and at what
frequencies. Utilizing these frequencies to compare to probable mode can-
didates calculated from Saturn models will also us to ascertain the interior
profiles of state variables such as density, sound speed, rotation, etc. Using
these profiles in a Saturn model, coupled with tweaking the interior struc-
ture of the model, i.e. the inclusion of stably stratified regions, should
allow us to explain which modes are responsible for the density structures
in the rings, as well as predict where to look to find more such structures.
In doing so, we will not only have a much greater understanding of Sat-
urn’s interior structure, but will have constructed a method that can also
be applied to Jupiter once observations of its mode frequencies become
available. In addition, we seek to explain if moist convection on Jupiter is
responsible for exciting its modes. We aim to do this by modeling Jupiter
as a 2D harmonic oscillator. By creating a resonance between moist con-
vective storms and Jovian modes, we hope to match the expected mode
energies and surface displacements of Jupiter’s oscillations.

Nov
18
Fri
Colloquium: Karen Olsen
Nov 18 @ 3:15 pm – 4:15 pm
Colloquium: Karen Olsen @ Biology Annex 102

Simulations of the interstellar medium at high redshift: What does [CII] trace?

Dr. Karen Olsen, Arizona State University

We are in an exciting era were simulations on large, cosmological scales meet modeling of the interstellar medium (ISM) on sub-parsec scales. This gives us a way to predict and interpret observations of the ISM, and in particular the star-forming gas, in high-redshift galaxies, useful for ongoing and future ALMA/VLA projects.

In this talk, I will walk you though the current state of simulations targeting the the fine structure line of [CII] at 158 microns, which has now been observed in several z>6 galaxies. [CII] can arise throughout the interstellar medium (ISM), but the brightness of the [CII] line depends strongly on local environment within a galaxy, meaning that the ISM phase dominating the [CII] emission can depend on galaxy type. This complicates the use of [CII] as a tracer of either SFR or ISM mass and calls for detailed modeling following the different ways in which [CII] can be excited.

I will present SÍGAME (Simulator of GAlaxy Millimeter/submillimeter emission) – a novel method for predicting the origin and strength of line emission from galaxies. Our method combines data from cosmological simulations with sub-grid physics that carefully calculates local radiation field strength, pressure, and ionizational/thermal balance. Preliminary results will be shown from recent modeling of [CII] emission from z~6 star-forming galaxies with SÍGAME. We find strong potential for using the total [CII] luminosity to derive the ISM and molecular gas mass of galaxies during the Epoch of Reionization (EoR).

 

Mar
3
Fri
Colloquium: Bart De Pontieu
Mar 3 @ 3:15 pm – 4:15 pm
Colloquium: Bart De Pontieu @ BX 102

Interface Region Imaging Spectrograph Views of How the Solar Atmosphere is Energized

Dr. Bart De Pontieu, Lockheed Martin

At the interface between the Sun’s surface and million-degree outer atmosphere or corona lies the chromosphere. At 10,000K it is much cooler than the corona, but also many orders of magnitude denser. The chromosphere processes all magneto-convective energy that drives the heating of the million-degree outer atmosphere or corona, and requires a heating rate that is at least as large as that required for the corona. Yet many questions remain about what drives the chromospheric dynamics and energetics and how these are connected to the transition region and corona.

The Interface Region Imaging Spectrograph (IRIS) is a NASA small explorer satellite that was launched in 2013 to study these questions. I will review recent results from IRIS in which observations and models are compared to study the onset of fast magnetic reconnection in the solar atmosphere, the generation of violent jets and how they feed plasma into the hot corona, and the role of nanoflares in heating the corona.

Mar
6
Mon
Pizza Lunch: F.X. Schmider
Mar 6 @ 12:30 pm – 1:30 pm
Pizza Lunch: F.X. Schmider

JIVE/JOVIAL, a network for Jupiter’s seismology and atmosphere dynamics

F.X. Schmider, Observatoire de la Cote d’Azur

Mar
10
Fri
Colloquium: Hazel Bain
Mar 10 @ 3:15 pm – 4:15 pm
Colloquium: Hazel Bain @ BX 102

Antarctic high altitude balloon observations of solar flares: Life and work on the ice

Dr. Hazel Bain, University of California, Berkeley

 

The Gamma-Ray Imager/Polarimeter for solar flares (GRIPS) instrument is a balloon-borne telescope designed to study particle acceleration in solar flares. The process through which stored magnetic energy is released and particles are accelerated to high energies in solar flares is not well understood. Hard x-rays and gamma-rays are direct signatures of these accelerated particles and can be used as a proxy to investigate particle acceleration mechanisms in these explosive events.

In the austral summer of 2016, GRIPS began its inaugural flight from NASA’s Long Duration Balloon (LDB) facility just outside McMurdo, Antarctica. During the 12 day flight, the balloon was carried around the Antarctic continent by the seasonal stratospheric polar vortex. At the end of the 2016 season, the data vaults were recovered however due to the lateness of the season a full recovery was scheduled for the following year.

In this talk I will discuss the GRIPS instrument design and science goals, the process of testing and integration leading up to a balloon launch, the inaugural flight and subsequent instrument recovery this year from the GRIPS landing site out in Antarctica’s “flat white”. I’ll also talk a little bit about life and work on the ice.

Apr
24
Mon
Pizza Lunch: Laurel Farris
Apr 24 @ 12:30 pm – 1:30 pm
Pizza Lunch: Laurel Farris @ AY 119

Determining the size of coronal bright points using cross-correlation methods

Laurel Farris

 

Sep
1
Fri
Colloquium: Isak Wold (Host: Moire Prescott)
Sep 1 @ 3:15 pm – 4:15 pm
Colloquium: Isak Wold (Host: Moire Prescott) @ BX102

A Faint Flux-Limited LAE Sample at z = 0.3

Isak Wold, UT Austin

Observational surveys of Lya emitters (LAEs) have proven to be an efficient method to identify and study large numbers of galaxies over a wide redshift range. To understand what types of galaxies are selected in LAE surveys – and how this evolves with redshift – it is important to establish a low-redshift reference sample that can be directly compared to high-redshift samples.  The lowest redshift where a direct Lya survey is currently possible is at a redshift of z~0.3 via the Galaxy Evolution Explorer (GALEX ) FUV grism data. Using the z~0.3 GALEX sample as an anchor point, it has been suggested that at low redshifts high equivalent width (EW) LAEs become less prevalent and that the amount of escaping Lya emission declines rapidly.  A number of explanations for these trends have been suggested including increasing dust content, increasing neutral column density, and/or increasing metallicity of star-forming galaxies at lower redshifts. However, the published z~0.3 GALEX sample is pre-selected from bright NUV objects.  Thus, objects with strong Lya emission but faint continuum (high-EW LAEs) could be missed.  In this talk, I will present my efforts to re-reduce the deepest archival GALEX FUV grism data and obtain a sample that is not biased against high-EW LAEs.  I will discuss the implications of this new sample on the evolutionary trends listed above.

Nov
9
Thu
Public Talk: “Preparing to Explore the Universe with the James Webb Space Telescope” – Dr. Jane Rigby (NASA Goddard)
Nov 9 @ 7:00 pm – 8:00 pm
Public Talk: "Preparing to Explore the Universe with the James Webb Space Telescope" - Dr. Jane Rigby (NASA Goddard) @ Gerald Thomas Hall, Room 194

Preparing to Explore the Universe with the James Webb Space Telescope

Dr. Jane Rigby (NASA Goddard, Deputy Project Scientist for JWST)

Abstract: NASA’s James Webb Space Telescope (JWST), scheduled to be launched in 2019, will revolutionize our view of the Universe.  As the scientific successor to the Hubble Space Telescope, JWST will rewrite the textbooks and return gorgeous images and spectra of our universe.   In my talk, I will show how JWST will revolutionize our understanding of how galaxies and supermassive black holes formed in the first billion years after the Big Bang, and how they evolved over cosmic time.  I’ll describe how our international team is preparing for launch, how we decide what targets to observe, and how we are testing the telescope to be sure it will work in space.

More information about the telescope can be found at https://www.jwst.nasa.gov/.