2002/12/04 by Cs. Kiss, P. Abraham, P. Ábrahám +6 · 27 citations
Physics and Astronomy · #Astrophysics and Star Formation Studies #Brightness #COSMIC cancer database #Cirrus #Galaxies: Formation, Evolution, Phenomena #Sky #Sky brightness #Solar and Space Plasma Dynamics #Spectral density #Spectral index #Wavelength #astro-ph
paper · pdf · doi:10.1051/0004-6361:20021787
published in Astronomy and Astrophysics 399(1), 177-185 (EDP Sciences) · 10 pages; 7 figures; Astronomy & Astrophysics, accepted
arxiv created 2002/12/04 · openalex publication_date 2003/02/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We examined the Fourier power spectrum characteristics of cirrus structures in 13 sky fields with faint to bright cirrus emission observed with ISOPHOT in the 90–200 μ m wavelength range in order to study variations of the spectral index α . We found that α varies from field to field with –5.3 ≤ α ≤ –2.1. It depends on the absolute surface brightness and on the hydrogen column density. We also found different spectral indices for the same sky region at different wavelengths. Longer wavelength measurements show steeper power spectra. This can be explained by the presence of dust at various temperatures, in particular of a cold extended component. For the faintest areas of the far-infrared sky we derive a wavelength-independent spectral index of α = –2.3 ± 0.6 for the cirrus power spectrum. The application of the correct spectral index is a precondition for the proper disentanglement of the cirrus foreground component of the Cosmic Far-Infrared Background and its fluctuations.