Calendar

Apr
5
Fri
Colloquium: Ylva Pihlström (Host: Moire Prescott)
Apr 5 @ 3:15 pm – 4:15 pm
Colloquium: Ylva Pihlström (Host: Moire Prescott) @ BX102

A Masing BAaDE’s Window

Ylva Pihlström, University of New Mexico

Evolved, intermediate mass stars are tracers of an intermediate age stellar population. Due to high mass-loss rates, they harbor circumstellar envelopes, in which different types of molecular maser emission can be observed. The maser emission allows not only studies of the physical conditions in the circumstellar envelope itself, but also can be used to test Galactic dynamics. Both these facets are investigated in the Bulge Asymmetries and Dynamical Evolution (BAaDE) survey, using 28,000 SiO maser emitting stars in the Milky Way galaxy observed by the VLA and ALMA. I will give an overview of this survey and discuss a few of our results and challenges: A marginal flux bias exists in our sample due to two different sets of frequencies observed, which could partly be corrected for using longer integration times at ALMA. We have collected an extensive infrared data set for our sample, providing a means of modeling parameters such as bolometric luminosities and mass loss rates. Infrared colors further helps to separate C-rich from O-rich stars, and may also be tied to line ratios, tying back to the conditions in the circumstellar envelope.

Apr
17
Wed
Special Colloquium: Amanda Wilber (Host: Moire Prescott)
Apr 17 @ 3:15 pm – 4:15 pm
Special Colloquium: Amanda Wilber (Host: Moire Prescott) @ AY 119

Searching for diffuse radio emission in merging galaxy clusters with LOFAR

Amanda Wilber, Universität Hamburg

Galaxy cluster mergers are powerful drivers of turbulence and shocks, which can accelerate cosmic-ray electrons within the magnetic field of the intracluster medium (ICM) to generate Megaparsec-sized radio structures. Actively merging clusters are excellent astrophysical laboratories for studying the nature of magnetic fields and the physics of particle acceleration. Questions still remain in identifying the source of cosmic-ray electrons that appear to fill the ICM so uniformly, and in determining the origin and amplification mechanisms of cluster magnetic fields. With its high-resolution, extended coverage, and sensitivity to radio emission with low surface brightness, the LOw Frequency ARray (LOFAR) Two-metre Sky Survey (LoTSS) gives us an unparalleled opportunity to hunt for diffuse radio sources in distant galaxy clusters. In this talk I present the results of LoTSS observations which reveal never-before-seen diffuse radio emission in the merging galaxy clusters Abell 1132 and Abell 1314.

Apr
22
Mon
Pizza lunch: Sarah Kovac/David DeColibus
Apr 22 @ 12:30 pm – 1:30 pm
Pizza lunch: Sarah Kovac/David DeColibus @ AY 119

ASTR 598

Apr
26
Fri
Colloquium: Megan Reiter (Host: Kristian Finlator)
Apr 26 @ 3:15 pm – 4:15 pm
Colloquium: Megan Reiter (Host: Kristian Finlator) @ BX102

The Role of Ecology in Star and Planet Formation

Megan Reiter, Royal Observatory Edinburgh

Understanding how feedback regulates star and planet formation is one of the outstanding unsolved problems in astrophysics. Stellar feedback affects all astrophysical scales: it shapes the interstellar medium and mass function of galaxies, determines the fragmentation and star formation efficiency of molecular clouds, and plays a central role in the geochemical evolution of terrestrial planets. High-mass stars shape the local star-forming environment – the ecology – via radiation pressure, stellar winds, photoionization, and supernovae. Photoionization is the least explored of these; however, recent numerical work suggests that it dominates the destruction of molecular clouds and planet-forming disks around stars born in clusters. These predictions depend critically on the dynamics of newborn stars and feedback-altered gas, but these quantities are poorly unconstrained. I will talk about two on-going surveys using ALMA, MUE/VLT, and M2FS/Magellan to measure gas and stellar kinematics in order to test the role of environment in shaping the outcome of star and planet formation.

Apr
29
Mon
Pizza lunch: Kristen Luchsinger
Apr 29 @ 12:30 pm – 1:30 pm
Pizza lunch: Kristen Luchsinger @ AY 119

ASTR 598

May
3
Fri
No Colloquium
May 3 @ 3:15 pm – 4:15 pm
No Colloquium @ BX102

Colloquium Title

Colloquium Speaker Name, Affiliation

Abstract text

May
10
Fri
No Colloquium (Final Exam Week)
May 10 @ 3:15 pm – 4:15 pm
No Colloquium (Final Exam Week) @ BX102

Colloquium Title

Speaker, Affiliation

Abstract text

Dec
2
Mon
Pizza lunch: ASTR 598 (Farhan and Oana)
Dec 2 @ 12:30 pm – 1:30 pm
Pizza lunch: ASTR 598 (Farhan and Oana) @ AY 119

ASTR 598

Farhan Hasan and Oana Vesa

Dec
4
Wed
Pizza lunch: ASTR 598 (Ali and Matt)
Dec 4 @ 12:00 pm – 1:00 pm
Pizza lunch: ASTR 598 (Ali and Matt) @ AY 119

ASTR 598

Ali Hyder and Matt Varakian

Dec
9
Mon
Pizza lunch: ASTR 598 (Minje)
Dec 9 @ 12:30 pm – 1:15 pm
Pizza lunch: ASTR 598 (Minje) @ AY 119

ASTR 598

Minje Boem