2026 Mid-American Regional Astrophysics Conference (MARAC)

MARAC will be held on the campus of the University of Arkansas in Fayetteville, AR on November 19-20, 2026

 

We invite abstracts for posters and contributed talks, especially from undergraduate students, graduate students, and postdocs! All professional scientists involved in teaching and/or research in astronomy, astrophysics, and space science are invited to attend.

 

Registration (Open Now through Nov 20): Registration at this link.

 

Abstract (Deadline Nov 6): Abstract submission at this link. 

 

The program will be announced here. 

 

Venue: The Janelle Y. Hembree Alumni House 

Parking is available on site for free.

 

Hotel: We have a block of rooms reserved at the Moxy hotel for Nov 19 and Nov 20 and will be held until Nov 5.  We will post information for how to reserve these rooms ASAP.

 

Keynote Speakers: Priyanka Chakraborty and Arnab Sarkar (University of Arkansas)

 

Thursday: Priyanka Chakraborty (University of Arkansas)

 

Title: Unlocking the High-Energy Universe with XRISM

 

Abstract: X-ray astronomy serves as a powerful probe of the high-energy Universe, enabling us to explore environments and phenomena otherwise hidden from view. By studying X-ray spectral lines, we can piece together the conditions and dynamics that drive some of the most powerful cosmic events. With the  launch of XRISM, we now have an observatory capable of capturing these signals in greater detail than ever before. Its high-resolution X-ray observations allow us to investigate the structure and behavior of superheated gas in accretion disks around black holes, as well as the complex interactions within X-ray binaries, where compact objects draw material from companion stars. These observations not only reveal the mechanisms driving accretion and outflows but also illuminate their role in regulating galaxy evolution. In this talk, I will share new XRISM results that, for the first time, reveal the inner workings of these cosmic engines, shedding light on the connection between compact objects and their larger-scale environments.

 

Friday:  Prof. Arnab Sarkar (University of Arkansas)

 

Title: Peering into the heart of cosmic giants: XRISM reveals complex thermal and velocity structures at the core of massive galaxy clusters

 

Abstract: Galaxy clusters grow through mergers and accretion along the cosmic web. The dynamics of their hot gas are central to understanding cluster evolution, since much of the injected kinetic energy drives bulk motions and turbulence. These motions can persist for billions of years, delaying thermalization and altering the energy balance of the ICM. While the hot ICM is often treated as being in hydrostatic equilibrium, both simulations and observations suggest that even apparently relaxed systems can harbor substantial gas motions. This raises a key question: do ‘relaxed’ clusters truly represent dynamical equilibrium, or does their calm appearance mask hidden bulk flows and turbulence?

 

X-ray astronomy has entered a new era with XRISM. Thanks to all engineers and scientists whose hard work made the XRISM mission possible. At the heart of XRISM is Resolve, a state-of-the-art X-ray microcalorimeter with unmatched spectral resolution capabilities. Resolve enables measurement of temperature, density, turbulence, and chemical composition of the ICM with unprecedented accuracy. These measurements will transform our understanding of galaxy clusters, shedding light on the impact of cooling flows, mergers, and feedback from supermassive black holes on their formation and evolution.

 

In this talk, I will present XRISM observations of several galaxy clusters. For the first time, these data reveal the intricate velocity and thermal structures present in cluster cores. These results highlight the complexity of intracluster dynamics and open a new window into the physics of cluster growth and evolution.

 

 

 

* Registration/Abstract Opened: Sep   

  - Registration will be open through the conference and on-site registration will be available.

* Abstract Deadline: Nov 6

* Program Announced: Nov 11

* Conference Dates: Nov 19-20 at The Janelle Y. Hembree Alumni House (https://www.arkansasalumni.org/s/1429/bp20/interior.aspx?pgid=3549&gid=1)

 

 

 

For questions, please contact Prof. Bret Lehmer