Date

Speaker

Title

Aug 28

Shardha Jogee

University of Texas at Austin

Organizational meeting.

Sep 4

No talk scheduled.

Sep 11

Sarah Tuttle

University of Texas at Austin

"Star Formation in Surprising Places: Investigating Blue Bulge/Red Disk Galaxies"

Sep 18

No talk scheduled.

Sep 25

Dr. Niall I. Gaffney & Dr. Weijia Xu

University of Texas at Austin: Texas Advanced Computing Center (TACC)

"Supporting Data Research at TACC"

Oct 2

Chao-Ling Hung

University of Hawaii, and Harvard/SAO

(host: Steve Finkelstein) "Origin and Evolution of High-Redshift Infrared-Luminous Galaxies"

abstract

Oct 9

Jeff Silverman

University of Texas at Austin

"High-Velocity Features in the Spectra of Type-Ia Supernovae"

Oct 16

No talk scheduled.

Oct 23

Brett W. Salmon

Texas A&M University

"Star-Forming Galaxies in the z>4 Universe"

Oct 24
Fri
2 PM

Mimi Song

University of Texas at Austin

(note: special rescheduled day and time) "Early Galaxies at Cosmic Dawn and Cosmic Noon"

Oct 30

Elena D'Onghia

University of Wisconsin-Madison

(host: Shardha Jogee) "Phase Wrapping in the Galactic Disk and Formation of the Thick Disk"

The formation of the thick disk in our Galaxy remains a challenge. Recent speculations about its origin tend to focus on feedback processes or radial stellar migration by resonant scattering as viable mechanisms to thicken the stellar disk. Using high-resolution simulations of disk galaxies, I will show first the (modest) role of radial stellar migration in thickening the disk. Second, I will present a study on the vertical heating and thickening of the Galaxy disk due to the impact of a visible satellite like Sagittarius dwarf galaxy and by dark matter clumps as predicted by the current cosmological framework.

Unlike earlier work, I find that direct heating of disk stars by a large satellite is not significant, because the satellite gravitational perturbation has little power at the frequencies resonant with the vertical stellar orbits. The satellite, instead, excites the formation of long bending waves in the stellar disk that are perpendicular to the Galactic plane, and the formation of retrograde rings that wobble and thicken the disk by a mechanism that I term "phase wrapping".

These results provide new insight about the formation of the thick disk, and have interesting implications in reproducing the recent observations of spatially dependent bulk vertical motions in the solar neighborhood and the Monoceros stream. I will show tests to discriminate among different theories for the upcoming GAIA and SDSS-IV data.

close

Nov 6

Daniel Perley

California Institute of Technology (Caltech)

(host: Jeff Silverman) "13 Billion Years of Cosmic History as Seen by Gamma-Ray Bursts"

abstract

Nov 13

No talk scheduled.

Nov 20

Brandon Bozek

University of Maryland

(host: Shardha Jogee) "Constraints on Axion Dark Matter"

abstract

Nov 27

Thanksgiving Day Holiday: Staff Holiday. No classes scheduled.

Dec 4
NHB 1.720
4 PM

C. Megan Urry

Yale University, and DeVaucouleurs Medalist

UT College of Natural Sciences 'Women in Science' Lecture: "Why so Few? The Dearth of Women in Science"