Skip to main content
Toward A High-Definition View of the Baryon Cycle and Its Impact on Galaxy Evolution
Add to Calendar 2024-02-21T20:45:00 2024-02-21T22:00:00 UTC Toward A High-Definition View of the Baryon Cycle and Its Impact on Galaxy Evolution Davey Laboratory 538
Start DateWed, Feb 21, 2024
3:45 PM
End DateWed, Feb 21, 2024
5:00 PM
Presented By
Fakhri Zahedy (University of North Texas and Carnegie Observatories)
Event Series: Astronomy Colloquium

The growth of galaxies is profoundly influenced by the interplay of gas accretion from/outflows into their surroundings. Observations of diffuse gas in this circum-galactic medium (CGM) provide the most direct means to understand this baryon cycle. However, traditional observations of the CGM are limited by the use of single background sightlines, providing only a 1D view of the CGM of individual galaxies. With my research program, I aim to study the CGM in higher spectral and spatial definitions than previously possible, to achieve a deeper understanding of the coevolution of galaxies and their gas. My talk will be in two parts:  (1) First, I will highlight my work using high-quality spectroscopic data from large ground- space-based telescopes to obtain the most robust constraints on the physical properties of the CGM to date. By using a novel spectral analysis technique I developed to extract physical properties of individual CGM gas clouds, I have found that the CGM is multiphase and complex, with large variations in elemental abundances and gas densities that indicate a multitude of physical origins. I will show that the absolute and relative abundances of different elements convey critical information about the origin of the gas and its physical connection to stars and star-forming regions within galaxies. (2) In the second part of my talk, I will introduce my current work and future plan to use gravitationally lensed distant quasars to characterize large-scale gas flows in the CGM over 12+ Gyr of cosmic history. With the multiple images of a lensed quasar acting as independent probes of the CGM of foreground galaxies, we can now move beyond traditional one-point sampling of the CGM and begin to spatially resolve its gas flows and characterize their physical properties. Next-generation telescopes and astronomical surveys are poised to transform our understanding of galaxy evolution within the coming decade, and I will end by showing that high-spatial definition studies of the CGM will be key to realizing that goal.

Astro Colloquium and 'coffee & cookies' department gathering (3:30-3:45pm)

Please join in 538 Davey or click the link to join: