Calendar

Sep
15
Fri
Colloquium: Lisa Winter (Host: Laura Boucheron)
Sep 15 @ 3:15 pm – 4:15 pm
Colloquium: Lisa Winter (Host: Laura Boucheron) @ BX102

Long duration solar gamma ray flares

Lisa Winter, LANL

Long duration solar gamma ray flares (LDGRFs) present a challenge to models of solar flares. While the gamma ray emission initially was thought to be the high energy extension of emission produced at the footprints of flare loops, LDGRFs are more energetic than expectations and last hours after the X-ray emission subsides. Evidence of gamma ray emission from flares on the backside of the Sun prompted the idea that LDGRFs instead are created from acceleration of particles in the shock waves of coronal mass ejections (CMEs). To determine which of these scenarios is more likely, we conducted a study of the flare and CME properties for LDGRFs detected by the Fermi Gamma-Ray Observatory. We also performed a reverse association analysis to determine which flares and CMEs do not produce gamma-ray emission. In this talk, these results are presented, showing that LDGRFs are most likely associated with CME acceleration.

Sep
20
Wed
Colloquium PhD Defense: Jean McKeever
Sep 20 @ 3:00 pm – 4:15 pm
Colloquium PhD Defense: Jean McKeever @ Business College 103

Asteroseismology of Red Giants: The Detailed Modeling of Red Giants in Eclipsing Binary Systems

Jean McKeever, NMSU

Asteroseismology is an invaluable tool that allows one to peer into the inside of a star and know its fundamental stellar properties with relative ease. There has been much exploration of solar-like oscillations within red giants with recent advances in technology, leading to new innovations in observing. The Kepler mission, with its 4-year observations of a single patch of sky, has opened the floodgates on asteroseismic studies. Binary star systems are also an invaluable tool for their ability to provide independent constraints on fundamental stellar parameters such as mass and radius. The asteroseismic scaling laws link observables in the light curves of stars to the physical parameters in the star, providing a unique tool to study large populations of stars quite easily. In this work we present our 4-year radial velocity observing program to provide accurate dynamical masses for 16 red giants in eclipsing binary systems. From this we find that asteroseismology overestimates the mass and radius of red giants by 15% and 5% respectively. We further attempt to model the pulsations of a few of these stars using stellar evolution and oscillation codes. The goal is to determine which masses are correct and if there is a physical cause for the discrepancy in asteroseismic masses. We find there are many challenges to modeling evolved stars such as red giants and we address a few of the major concerns. These systems are some of the best studied systems to date and further exploration of their asteroseismic mysteries is inevitable.

 

Sep
29
Fri
Campus Observatory Open House
Sep 29 @ 8:00 pm – 9:00 pm
Campus Observatory Open House @ Campus Observatory

Welcome to the first open house of the 2017 Fall Semester. Your hosts will be: James McAteer, Jodi Berdis, Carlos Vargas, and Julie Imig.

The (September) Autumnal Equinox.

September Night Sky Chart.

Oct
2
Mon
Pizza Lunch: Sarah Kovac
Oct 2 @ 12:30 pm – 1:30 pm
Pizza Lunch: Sarah Kovac @ AY 119

The Citizen Cate Project

Oct
13
Fri
Colloquium: Kyoung-Soo Lee (Host: Moire Prescott)
Oct 13 @ 3:15 pm – 4:15 pm
Colloquium: Kyoung-Soo Lee (Host: Moire Prescott) @ BX102

Colloquium Title

Kyoung-Soo Lee, Purdue University

Abstract text

Oct
16
Mon
Pizza Lunch: Ken Naiff
Oct 16 @ 12:30 pm – 1:30 pm
Pizza Lunch: Ken Naiff @ AY 119

Dark Sky Images

Ken Naiff

Ken, an retired engineer, is a highly technically skilled and artistic
astrophotographer.  He will be sharing some of his work and elaborating on
the technical methods and processing techniques he applies to obtain his
unique and enhanced images.  You can see Ken’s work at:

https://darkskyimagesbyken.com/products

 

Oct
20
Fri
Colloquium: Benjamin Oppenheimer (Host: Kristian Finlator)
Oct 20 @ 3:15 pm – 4:15 pm
Colloquium: Benjamin Oppenheimer (Host: Kristian Finlator) @ BX102

Breaking the Self-Similarity of Galaxy Formation: A Circumgalactic Medium Perspective

Benjamin Oppenheimer, University of Colorado Boulder

If you could see a dark matter halo directly without knowing the scale, you probably could not distinguish a Milky Way halo from a cluster-sized halo.  However, if you look at the galaxies, you would likely see a dominant spiral galaxy in the former and a many quenched and quenching galaxies in the latter.  The study of galaxy formation aims to understand how very different galaxies form in dark matter halos of different masses.  I will argue for the importance of understanding the gaseous baryons in this context.  In contrast to the hot intracluster medium detected in emission in clusters, the circumgalactic medium (CGM) has to be probed by absorption lines toward background quasars and tells a vastly different and complicated story.  I will demonstrate, with the aid of hydrodynamic simulations, how the CGM is multi-phase (with cool ~10^4 K clouds embedded in a hot, ambient medium), plus how non-equilibrium ionization processes altering the heavy element ions we probe in spectra.  The next frontiers in the CGM require understanding the dynamics encoded not only in absorption line spectra of the UV, but in the X-ray via emission and absorption.

 

 

Oct
23
Mon
Pizza Lunch: Kristian Finlator
Oct 23 @ 12:30 pm – 1:30 pm
Pizza Lunch: Kristian Finlator @ AY 119

Vastly Improved Simulations of the Hydrogen Reionization Epoch: Too Much for One Paper?

Oct
27
Fri
Observatory Open House
Oct 27 @ 8:00 pm – 9:00 pm
Observatory Open House

Your hosts for the October Open House at the Campus Observatory are Kristian Finlator, Sten Hasselquist, Rachel Marra, and Aleczander Herczeg.

The Calendar of Astronomical Events for October 2017

October Night Sky Chart.

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

Cool Science Results