2005/04/06 by Roberto Fusco-Femiano, R. Fusco‐Femiano, R. Landi +3 · 2 citations
Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Star Formation Studies #Cluster (spacecraft) #Coma Cluster #Epoch (astronomy) #Flux (metallurgy) #Galaxy #Galaxy cluster #Gamma-ray bursts and supernovae #Materials science #Physics #Range (aeronautics) #Spectral line #astro-ph
paper · pdf · doi:10.1086/430736
published as Astrophys.J. 624 (2005) L69-L72 · 12 pages, 3 figures, 1 table - ApJL, in press
arxiv created 2005/04/06 · openalex publication_date 2005/04/19 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
After confirmation of the presence of a nonthermal hard X-ray excess with respect to the thermal emission in the Coma Cluster from two independent observations, obtained using the Phoswich Detection System on board BeppoSAX , we also present in this Letter the results of two observations of A2256 performed with a time interval of about 2.5 yr. In both spectra a nonthermal excess is present at a confidence level of ~3.3 σ and ~3.7 σ, respectively. The combined spectrum obtained by adding up the two spectra allows us to measure an excess at the level of ~4.8 σ in the 20-80 keV energy range. The nonthermal X-ray flux is in agreement with the published value of the first observation (Fusco-Femiano et al.) and with that measured by a Rossi X-Ray Timing Explorer observation (Rephaeli & Gruber).