2/8/2021

Galaxies & Cosmology & Stars & Planets Seminar

Monday, February 8, 2021 - 11:00am

Zoom

The Formation of Isolated Ultra-Diffuse Galaxies in Romulus25

Speaker:

Anna Wright

Institution:

Johns Hopkins

Visitor Schedule

Host:

Anna Rosen

Abstract

Although low surface brightness (LSB) galaxies make up a significant fraction of the galaxy population, it is only within the last few years that they have been studied in large numbers. Consequently, the methods by which they form and evolve, as well as the extent to which these processes fit within the commonly accepted paradigms of galaxy evolution and cosmology lack a consensus. In this talk, I discuss the properties and evolution of ultra-diffuse galaxies (UDGs), a subset of the LSB galaxy population characterized by dwarf-like luminosities, but light profiles that can extend as far as those of Milky-Way-mass galaxies. In the Romulus25 cosmological simulation, we find that isolated UDGs are the products of early major mergers that produce a temporary boost in spin and cause star-forming gas to be redistributed from the centers of the galaxies to larger radii.

New Ways of Magnetic Field Tracing: Implications for ISM, Cluster of Galaxies and CMB polarization studies

Speaker2:

Alex Lazarian

Institution2:

UW Madison

Visitor Schedule

Host2:

Marion Dierickx

Abstract

What is the key information that is important for very distant branches of research, e.g. search for cosmological B-modes, studies HI at high redshifts, cosmic ray studies, star formation research? The answer is simple: detailed information about astrophysical magnetic fields. While Planck, ALMA, SOFIA and other projects advanced our knowledge of these mysterious fields, the limitations related to far-infrared polarimetry constrain our progress. The work that I am going to advertise during my short talk is intended to change this situation by employing the vast amount of data that has not been used earlier for magnetic field studies. In particular, I am going to discuss the use of existing large data sets of spectroscopic data for obtaining magnetic field direction and magnetic field strength over a wide range of astrophysical scales. I am going to show magnetic field maps obtained with our new Gradient Technique for various objects from molecular clouds, Milky Way, nearby galaxies to clusters of galaxies. If time permits, I will describe the physical foundations of the new technique and outline its prospects for determining the full 3D maps of 3D magnetic field vectors using observational data.

Event Status:

Active

2/8/2021

Events