Calendar

Nov
6
Mon
Pizza Lunch: Ethan Dederick
Nov 6 @ 12:30 pm – 1:30 pm
Pizza Lunch: Ethan Dederick @ AY 119

Cool Science Results

Nov
9
Thu
Special Pizza Lunch: Jane Rigby
Nov 9 @ 1:00 pm – 2:00 pm
Special Pizza Lunch: Jane Rigby @ AY 119

Galaxy Evolution in High Definition Via Gravitational Lensing

Dr. Jane Rigby

Deputy Project Scientist for JWST, NASA Goddard Space Flight Center

Abstract: In hundreds of known cases, “gravitational lenses” have deflected, distorted, and amplified images of galaxies or quasars behind them.  As such, gravitational lensing is a way to “cheat” at studying how galaxies evolve:  lensing can magnify galaxies by factors of 10–100 times, transforming them from objects we can barely detect to bright objects we can study in detail.   For such rare objects, we are studying how galaxies formed stars at redshifts of 1–4, the epoch when most of the Universe’s stars were formed. For lensed galaxies, we can obtained spectral diagnostics that are currently unavailable for the distant universe, but will become routine with next-generation telescopes.

In particular, I’ll discuss MEGaSaURA, The Magellan Evolution of Galaxies Spectroscopic and Ultraviolet Reference Atlas, which comprises high signal-to-noise, medium spectral resolution (R~3300) spectra of 15 extremely bright gravitationally lensed galaxies at redshifts of 1.6<z<3.6.   The sample, drawn from the SDSS Giant Arcs Survey, are many of the brightest lensed galaxies known.  The MEGaSaURA spectra reveal a wealth of spectral diagnostics: absorption from the outflowing wind; nebular emission lines that will be key diagnostics for JWST, GMT, and TMT; and photospheric absorption lines and P Cygni profiles from the massive stars that power the outflow.

Nov
13
Mon
Pizza Lunch: James Lewis
Nov 13 @ 12:30 pm – 1:30 pm
Pizza Lunch: James Lewis @ AY 119

Multivariate Analysis of the CGM

Nov
27
Mon
Pizza Lunch: Rachel Marra and Trevor Picard
Nov 27 @ 12:30 pm – 1:30 pm
Pizza Lunch: Rachel Marra and Trevor Picard @ AY 119

ASTR 598 Talk

Dec
4
Mon
Pizza Lunch: Karen Kinemuchi
Dec 4 @ 12:30 pm – 1:30 pm
Pizza Lunch: Karen Kinemuchi @ AY 119

Life at Apache Point Observatory

Feb
26
Mon
Pizza Lunch: Shuo Wang
Feb 26 @ 12:30 pm – 1:30 pm
Pizza Lunch: Shuo Wang @ AY 119
Mar
2
Fri
Colloquium PhD Thesis Defense: Gordon MacDonald
Mar 2 @ 3:15 pm – 4:15 pm
Colloquium PhD Thesis Defense: Gordon MacDonald @ BX102

Colloquium Title

Gordon MacDonald, NMSU

Abstract

Mar
5
Mon
Pizza Lunch: Rene Walterbos
Mar 5 @ 12:30 pm – 1:30 pm
Pizza Lunch: Rene Walterbos @ AY 119
Mar
12
Mon
Pizza Lunch: Caitlin Doughty
Mar 12 @ 12:30 pm – 1:30 pm
Pizza Lunch: Caitlin Doughty @ AY 119

Using CGM metal absorbers to look for galaxies

Mar
28
Wed
Colloquium PhD Thesis Defense: Ethan Dederick
Mar 28 @ 3:15 pm – 4:15 pm
Colloquium PhD Thesis Defense: Ethan Dederick @ Science Hall 109

Seismic Inferences of Gas Giant Planets: Excitation & Interiors

Ethan Dederick, NMSU

Seismology has been the premier tool of study for understanding the interior structure of the Earth, the Sun, and even other stars. In this thesis we develop the framework for the first ever seismic inversion of a rapidly rotating gas giant planet. We extensively test this framework to ensure that the inversions are robust and operate within a linear regime. This framework is then applied to Saturn to solve for its interior density and sound speed profiles to better constrain its interior structure. This is done by incorporating observations of its mode frequencies derived from Linblad and Vertical Resonances in Saturn’s C-ring. We find that although the accuracy of the inversions is mitigated by the limited number of observed modes, we find that Saturn’s core density must be at least 8.97 +/- 0.01 g cm^{-3} below r/R_S = 0.3352 and its sound speed must be greater than 54.09 +/- 0.01 km s^{-1} below r/R_S = 0.2237. These new constraints can aid the development of accurate equations of state and thus help determine the composition in Saturn’s core. In addition, we investigate mode excitation and whether the \kappa-Mechanism can excite modes on Jupiter. While we find that the \kappa-Mechanism does not play a role in Jovian mode excitation, we discover a different opacity driven mechanism, The Radiative Suppression Mechanism, that can excite modes in hot giant planets orbiting extremely close to their host stars if they receive a stellar flux greater than 10^9~erg cm^{-2} s^{-1}. Finally, we investigate whether moist convection is responsible for exciting Jovian modes. Mode driving can occur if, on average, one cloud column with a 1-km radius exists per 6423 km^2 or if ~43 storms with 200 columns, each with a radius of 25 km, erupt per day. While this seems unlikely given current observations, moist convection does have enough thermal energy to drive Jovian oscillations, should it be available to them.