Quasi-periodic eruptions: past, present, and future
Riccardo Arcodia (Harvard University)

X-ray Quasi-Periodic Eruptions (QPEs) are the latest and perhaps the most peculiar addition to the zoo of extragalactic nuclear transients. They are high-amplitude bursts of X-ray radiation recurring every few hours to few days with a lifetime of years to decades, originating from the central black holes in the nuclei of low-mass galaxies. So far, only a dozen of such events has been found, although with rising interest in the broader community given their observational and theoretical connection with tidal disruption events and as possible low-frequency gravitational wave sources. I will begin with an outline of the observational properties of QPE sources and their current interpretation, and conclude with an outlook on the future of QPEs and X-ray nuclear transients in light of the next generation of X-ray missions.

Please join us for the SED Director’s Seminar, hosted by the X-ray Astrophysics Laboratory, Code 662!

Fundamental Atomic Spectroscopy for Astrophysics: From Benchmark Databases to Spectral Modeling
Dr. Yuri Ralchenko

Precision Spectroscopic Measurements for Space Science
Dr. Jacob Ward

Why Fermi Sees the Pulsars It Sees: Gamma-ray Visibility, Hidden MeV Pulsars, and the GeV-TeV Connection
Dr. Gabriel Grell

Reigniting the FUSE: A Modern Reanalysis of the Cooling Flow Problem with Archival UV Spectroscopy
Michael Reefe

Abstract: The “cooling flow problem“ refers to the discrepancy between the cooling rates of gas in the hot intracluster/circumgalactic medium and star formation rates in the central galaxy. This ~2 orders of magnitude disagreement have been explained by feedback from an active galactic nucleus, which reheats and redistributes the gas. While the evidence for AGN feedback is compelling, many details of the cooling and feedback cycle remain elusive. A promising avenue for studying cooling processes at a finer detail is through “coronal” emission lines, which probe gas at intermediate temperatures (between the hot gas and the star formation). In this talk, I will present the results of a comprehensive archival study of 29 massive elliptical galaxies observed by FUSE. This far-ultraviolet spectroscopy has been re-analyzed with modern methods, in tandem with broadband photometry in the optical to IR. These data provide the strongest constraints to date on (i) the metallicity of the young, still-forming stellar populations in massive galaxies, (ii) the rate of star formation in massive galaxies, and the likely origin for the star-forming gas, and (iii) the cooling rate out of the hot phase via the OVI emission line doublet. Additionally, a new collection of high-resolution UV stellar templates, necessitated by this project, has been ported to the popular stellar population synthesis code FSPS and made publicly available.

AGU's annual meeting to share research with the global Earth and space science community.

AGU's annual meeting to share research with the global Earth and space science community.

AGU's annual meeting to share research with the global Earth and space science community.