Calendar

Apr
27
Fri
Galaxy Group Meeting
Apr 27 @ 12:30 pm – 1:00 pm
Apr
30
Mon
Pizza Lunch: Jon Holtzman
Apr 30 @ 12:30 pm – 1:30 pm
Pizza Lunch: Jon Holtzman @ AY 119

APOGEE and the Milky Way disk

PDS Atmospheres Node meeting
Apr 30 @ 3:00 pm – 4:00 pm
May
3
Thu
Inclusive Astronomy
May 3 @ 12:30 pm – 1:30 pm
May
4
Fri
Galaxy Group Meeting
May 4 @ 12:30 pm – 1:00 pm
May
7
Mon
Pizza Lunch: Sean Sellers and Alysha Shugart
May 7 @ 12:30 pm – 1:30 pm
Pizza Lunch: Sean Sellers and Alysha Shugart @ AY 119

ASTR 598

May
9
Wed
Colloquium Thesis Proposal: Caitlin Doughty
May 9 @ 2:15 pm – 3:15 pm
Colloquium Thesis Proposal: Caitlin Doughty @ Science Hall 107

Metal Absorption in the Circumgalactic Medium During the Epoch of Reionization

Caitlin Doughty, NMSU

The characteristics of metal absorption arising from the circumgalactic medium of galaxies have been demonstrated to be related to conditions in the galaxy which sourced them, as well as to the ambient ultraviolet background. I propose a three- pronged thesis in order to better understand and utilize these relationships. First, I will explore whether the spectral energy distributions of binary stars, incorporated into a custom version of GADGET-3, can explain the discrepancy between observed and simulated absorber statistics. Second, I will study the relationship between neu- tral oxygen absorbers and the neutral hydrogen fraction in simulated quasar sight- lines and relate the results to observations of neutral oxygen at z ≥ 4.0. Third, I will study the relationships between the emissive properties of galaxies, stemming from their nebular gas, and the metal absorbers which they source. Taken as a whole, this thesis will improve the ability of cosmological simulations to reproduce realistic metal absorption, probe the local progress and topology of reionization, and under- stand what emissive galaxy traits we expect at z > 5 based on observations of metal absorbers.

May
11
Fri
Colloquium PhD Thesis Defense: Kathryn Steakley
May 11 @ 2:15 pm – 3:30 pm
Colloquium PhD Thesis Defense: Kathryn Steakley @ BX102

Impact heating of the early Martian climate

Kathryn Steakley, NMSU Astronomy

The nature of Mars’ ancient climate has been the subject of debate for decades. Abundant geologic evidence suggests that liquid water flowed on the surface of Mars during the late Noachian and early Hesperian eras (~3.5 – 3.8 billion years ago), but climate models struggle to reproduce such warm and wet conditions. Characterizing the climate that supported this aqueous activity and constraining the duration and intensity of warm and wet periods is crucial to understanding whether Mars was habitable in the past. 1-D climate modeling studies suggest that asteroid impacts are capable of inducing greenhouse warming on early Mars due to the substantial amounts of energy and water that are injected into the atmosphere (Segura et al., 2008). We use a 3-D global climate model (GCM) to simulate the post-impact climate conditions presented in Segura et al. (2008) (30-, 50-, and 100-km impactors in 150 mbar, 1 bar, and 2 bar atmospheres) and examine the resulting global distributions of surface temperatures and precipitation to assess whether these post-impact climates can facilitate valley network formation in Mars’ southern highlands. We find that these post-impact scenarios do result in above-freezing temperatures and 10s of cm of rainfall in the southern highlands, but that ultimately these warm and wet periods are short lived (on the order of years) and do not support the sustained warm and wet conditions that facilitate valley network formation. We find that scenarios with high surface pressures and scenarios with radiatively active clouds experience longer periods of above-freezing temperatures and result in higher final mean annual temperatures (up to 272.8K in our warmest scenario). In future work, we will investigate other greenhouse gases delivered by impacts in addition to water, including hydrogen and/or methane, to test whether this prolongs the warm and wet periods following impacts.

Observatory Open House
May 11 @ 9:00 pm – 10:00 pm
Observatory Open House

Your hosts for the May Campus Observatory Open House are Nancy Chanover, Trevor Picard, and Drew Chojnowski.

Jun
21
Thu
Pizza Lunch: Michael Hayden
Jun 21 @ 12:00 pm – 1:00 pm
Pizza Lunch: Michael Hayden @ AY 119

Chemical Cartography of the Milky Way

Michael Hayden, Sydney Institute for Astronomy (NMSU alumnus)