Fabrizio Nicastro

TL;DR: In this article, the first results from the pilot 500 ks Chandra-LETG Large Program observation of the soft X-ray brightest source in the z>=0.4 sky, the blazar 1ES 1553+113, aimed to secure the first uncontroversial detections of the missing baryons in the X-rays.

TL;DR: In this article, the authors present follow-up observations to the original discovery and characterization of this "changing-look" active galactic nucleus (AGN), showing that the soft excess is not due to reprocessed hard X-ray emission, but is connected to the UV continuum through warm Comptonization.

TL;DR: In this article, an analysis of X-ray high-quality grating spectra of the Seyfert 1 galaxy NGC 5548 was carried out using archival Chandra-High Energy Transmission Grating Spectrometer and low energy transmission Grating spectrometer observations for a total exposure time of 800 ks.

TL;DR: In this paper, a micro-calorimeters-based detector was proposed to detect and characterize the physical state of the missing baryons at low redshift by analyzing the X-ray absorption spectra of the Gamma Ray Burst [GRB] afterglows, measured by a micro calorimeters based detector with 3 eV resolution and 1000 cm2 effective area.

TL;DR: In this article, the authors presented a possible O VIII X-ray absorption line at z = 0.1183 {+-} 0.0001 which, if confirmed, will be the first one associated with a broad H I Ly{beta} (BLB: FWHM = 160{sup +50} {sub -30} km s{sup -1}) absorber.