Only a handful of observations truly constrain the nature of dark matter, which is why dozens of different physical models are still viable. Several of the most popular alternatives predict that dark matter halos slowly “thermalize” over time, gradually changing shape and expanding until they form a central region of nearly constant density -- a core. This transformation would not occur if the dark matter particles were completely collision-less, as assumed in the standard model. Therefore, the presence or absence of such a core provides a powerful way to distinguish between the standard

Type 2 quasars (QSO2s) are active galactic nuclei (AGN) seen through a significant amount of dust and gas that obscures the central supermassive black hole and the broad-line region. Here, we present new mid-infrared spectra of the central kiloparsec of five optically selected QSO2s at redshift z ∼ 0.1 obtained with the Medium Resolution Spectrometer module of the Mid-Infrared Instrument (MIRI) aboard the James Webb Space Telescope (JWST). These QSO2s belong to the Quasar Feedback (QSOFEED) sample, and they have bolometric luminosities of log L bol  = 45.5 to 46.0 erg s −1 , global star

Dormant black holes in X-ray transients can be identified by the presence of broad Hα emission lines from quiescent accretion discs. Unfortunately, short-period cataclysmic variables can also produce broad Hα lines, especially when viewed at high inclinations, and are thus a major source of contamination. Here we compare the full width at half maximum (FWHM) and equivalent width (EW) of the Hα line in a sample of 20 quiescent black hole transients and 354 cataclysmic variables (305 from SDSS I to IV) with secure orbital periods (Porb) and find that: (1) FWHM and EW values decrease with Porb