March 29, 2022

Speaker: Christopher Reynolds (in-person)

Contact Information: csr12@cam.ac.uk

Title: Searching for axion-like particles with X-ray observations of galaxy clusters.

Abstract: There has been a surge of interest within the particle-physics and dark matter communities in axions and axion-like particles (ALPs). These particles result from a possible extensions to the Standard Model that may solve the Strong-CP problem, and are further motivated by String Theory. Galaxy clusters are a superb laboratories for exploring ALP physics. Clusters are permeated by a magnetized hot intracluster medium (ICM) that can efficiently interconvert photons and ALPs. Here, I discuss how the transparency (or lack thereof) of the ICM to X-rays becomes a powerful way to constrain ALPs. I show that a careful examination of X-ray observations of cluster-hosted active galactic nuclei (AGN) by the Chandra X-ray Observatory allow the tightest constraints to date on ALP/photon coupling of ALPs in the low-mass regime (ALP masses less than ~peV). I finish by discussing the future prospects of these studies with the next generation X-ray observatories.

Visitor's room: 125

Visit Schedule:

Monday (28 Mar. 2022):

  • 10:30 a.m.: Astro Coffee (virtual)

  • 11:00 a.m.: Christopher Bambic

  • 11:30 a.m.:

  • 12:00 p.m.: CR unavailable (meeting)

  • 12:30 p.m.: CR unavaiable (meeting)

  • 2:00 p.m.: Archie Bott (Room 125)

  • 2:30 p.m.: Matt Coleman (Room 109a)

  • 3:00 p.m.: Jenny Greene (room 001)

  • 3:30 p.m.: Neta Bahcall (rm 137)

  • 4:00 p.m.: Jo Dunkley (rm 125)

  • 4:30 p.m.: Jeremy Goodman (rm 129)

  • 5:00 p.m.:

Tuesday (29 Mar. 2022):

  • 10:00 a.m.: Andy Goulding (117)

  • 10:30 a.m.: Prep time

  • 11:00 a.m.: Colloquium

  • 12:30 p.m.: Bahcall Lunch

  • 2:00 p.m.: Anatoly Spitkovsky (rm123)

  • 2:30 p.m.: Eve (rm. 136)

  • 3:00 p.m.: Grad Students/Grad Tea (033)

  • 3:30 p.m.: Grad Students/Grad Tea (033)

  • 4:00 p.m.: Bart Ripperda (rm 132)

  • 4:30 p.m.: Michael Strauss (Peyton 113)

  • 5:00 p.m.: Eliot 127

  • 5:30 p.m.: Alisa Galishnikova

  • 6:00 p.m.: DINNER - meet in Grand Central

Dinner Sign-up - add your name here:

  1. Christopher Reynolds

  2. Faculty host: Eve Ostriker

  3. Postdoc host: Archie Bott

  4. Matt Coleman

  5. Andy Goulding

  6. Keduse Worku


PLEASE NO MORE THAN 8 PEOPLE (it is more difficult to properly interact with the speaker with larger groups). STUDENTS HAVE PRIORITY.