Calendar

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

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
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

 

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

Mar
29
Thu
Colloquium (Joint with Physics): Jim Fuller (Host: Ethan Dederick)
Mar 29 @ 4:00 pm – 5:00 pm
Colloquium (Joint with Physics): Jim Fuller (Host: Ethan Dederick) @ Gardiner Hall 230

Surprising Impacts of Gravity Waves

Jim Fuller, Caltech

Gravity waves are low frequency fluid oscillations restored by buoyancy forces in planetary and stellar interiors. Despite their ubiquity, the importance of gravity waves in evolutionary processes and asteroseismology has only recently been appreciated. For instance, Kepler asteroseismic data has revealed gravity modes in thousands of red giant stars, providing unprecedented measurements of core structure and rotation. I will show how gravity modes (or lack thereof) can also reveal strong magnetic fields in the cores of red giants, and I will demonstrate that strong fields appear to be common within “retired” A stars but are absent in their lower-mass counterparts. In the late phase evolution of massive stars approaching core-collapse, vigorous convection excites gravity waves that can redistribute huge amounts of energy within the star. I will present preliminary models of this process, showing how wave energy redistribution can drive outbursts and enhanced mass loss in the final years of massive star evolution, with important consequences for the appearance of subsequent supernovae.
Apr
6
Fri
Colloquium PhD Thesis Defense: Sten Hasselquist
Apr 6 @ 3:15 pm – 4:15 pm
Colloquium PhD Thesis Defense: Sten Hasselquist @ BX102

Colloquium Title

Sten Hasselquist, NMSU

Abstract

Sep
21
Fri
Colloquium: Dave Thilker (Host: Rene Walterbos)
Sep 21 @ 3:15 pm – 4:15 pm
Colloquium: Dave Thilker (Host: Rene Walterbos) @ BX102

Fresh Perspectives on Star Formation from LEGUS, the Legacy ExtraGalactic Ultraviolet Survey

David Thilker, Johns Hopkins University

The Legacy ExtraGalactic Ultraviolet Survey (LEGUS) was a Cycle 21 Large Treasury HST program which obtained ~parsec resolution NUV- to I-band WFC3 imaging for 50 nearby, representative star-forming Local Volume galaxies, with a primary goal of linking the scales of star formation from the limit of individual stars, to clusters and associations, eventually up through the hierarchy to giant star forming complexes and galaxy-scale morphological features.

I will review the basics of the survey, public data products and science team results pertaining to clusters and the field star hierarchy.  I will then describe work to optimize photometric selection methods for massive main sequence O star candidates and LBV candidates, in the former case establishing a means to statistically constrain the fraction of O stars in very isolated locales.  I will introduce new ideas on how to quantify the complex spatio-temporal nature of hierarchical star formation using multi-scale clustering methods. The first steps of this work have yielded a landmark OB association database for 36 LEGUS target fields (in 28 of the nearest available galaxies), with tracer stellar populations selected and interpreted uniformly.  I will finish with discussion of a pilot HST program to demonstrate remarkably increased survey efficiency of WFC3 UV imaging enabled by use of extra-wide (X) filter bandpasses.  Such efficiency is required as we move beyond LEGUS and begin to rigorously explore low surface brightness star-forming environments where canonical results for the IMF and cluster formation efficiency are increasingly called into question.

 

Aug
30
Fri
Colloquium: Lisa Young (Host: Rene Walterbos)
Aug 30 @ 3:15 pm – 4:15 pm
Colloquium: Lisa Young (Host: Rene Walterbos) @ BX102

Cold Gas and the Evolution of Early-type Galaxies

Lisa Young, New Mexico Tech

A major theme of galaxy evolution is understanding how today’s Hubble sequence was
established — what makes some galaxies red spheroidals and others blue disks, and what
drives their relative numbers and their spatial distributions. One way of addressing these
questions is that galaxies themselves hold clues to their formation in their internal
structures. Recent observations of early-type galaxies in particular (ellipticals and
lenticulars) have shown that their seemingly placid, nearly featureless optical images can
be deceptive. Kinematic data show that the early-type galaxies have a wide variety of
internal kinematic structures that are the relics of dramatic merging and accretion
events. A surprising number of the early-type galaxies also contain cold atomic and
molecular gas, which is significant because their transitions to the red sequence must
involve removing most of their cold gas (the raw material for star formation). We can now
also read clues to the evolution of early-type galaxies in the kinematics and the
metallicity of their gas, and possibly also in the rare isotope abundance patterns in the
cold gas. Numerical simulations are beginning to work on reproducing these cold gas
properties, so that we can place the early-type galaxies into their broader context.

(incomplete video)

Oct
28
Mon
Pizza Lunch: Sultan Hassan
Oct 28 @ 12:30 pm – 1:30 pm
Pizza Lunch: Sultan Hassan @ AY 119

What can DLAs tell us about galaxy formation?

Nov
22
Fri
Colloquium: Rixin Li (Host: Wladimir Lyra)
Nov 22 @ 3:15 pm – 4:15 pm
Colloquium: Rixin Li (Host: Wladimir Lyra) @ BX102

Simulating Planetesimal Formation in the Kuiper Belt and Beyond

Rixin Li, University of Arizona

A critical step in planet formation is to build super-km-sized planetesimals in protoplanetary disks. The origin and demographics of planetesimals are crucial to understanding the Solar System, circumstellar disks, and exoplanets. I will overview the current status of planetesimal formation theory. Specifically, I will present our recent simulations of planetesimal formation by the streaming instability, a mechanism to aerodynamically concentrate pebbles in protoplanetary disks. I will then discuss the connections between our numerical models and recent astronomical observations and Solar System explorations. I will explain why all planetesimals likely formed as binaries.