Calendar

Sep
14
Mon
Pizza Lunch: Kristian Finlator
Sep 14 @ 12:30 pm – 1:30 pm
Pizza Lunch: Kristian Finlator

The Slope of the Extragalactic UVB

Oct
2
Fri
Colloquium: Rodolfo Montez Jr.
Oct 2 @ 3:15 pm – 4:15 pm
Colloquium: Rodolfo Montez Jr. @ BX102

Insights into Binary Stars, Stellar Winds, and Astrophysical Plasmas from X-ray Observations of Planetary Nebulae

Rodolfo Montez Jr., Vanderbilt University

 

Dec
4
Fri
Colloquium: Brian Jackson
Dec 4 @ 3:15 pm – 4:15 pm
Colloquium:  Brian Jackson @ BX102

On the Edge: Exoplanets with Orbital Periods Shorter Than a Peter Jackson Movie

Brian Jackson, Boise State Univeristy

From wispy gas giants to tiny rocky bodies, exoplanets with orbital periods of several days and less challenge theories of planet formation and evolution. Recent searches have found small rocky planets with orbits reaching almost down to their host stars’ surfaces, including an iron-rich Mars-sized body with an orbital period of only four hours. So close to their host stars that some of them are actively disintegrating, these objects’ origins remain unclear, and even formation models that allow significant migration have trouble accounting for their very short periods. Some are members of multi-planet system and may have been driven inward via secular excitation and tidal damping by their sibling planets. Others may be the fossil cores of former gas giants whose atmospheres were stripped by tides.

In this presentation, I’ll discuss the work of our Short-Period Planets Group (SuPerPiG), focused on finding and understanding this surprising new class of exoplanets. We are sifting data from the reincarnated Kepler Mission, K2, to search for additional short-period planets and have found several new candidates. We are also modeling the tidal decay and disruption of close-in gaseous planets to determine how we could identify their remnants, and preliminary results suggest the cores have a distinctive mass-period relationship that may be apparent in the observed population. Whatever their origins, short-period planets are particularly amenable to discovery and detailed follow-up by ongoing and future surveys, including the TESS mission.

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.

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