Fitting AGN/Galaxy X-Ray-to-radio SEDs with CIGALE and Improvement of the Code

Guang Yang, Médéric Boquien, W. N. Brandt, Véronique Buat, Denis Burgarella, Laure Ciesla, Bret D. Lehmer, Katarzyna Małek, George Mountrichas, Casey Papovich, Estelle Pons, Marko Stalevski, Patrice Theulé, Shifu Zhu

Research output: Contribution to journalArticlepeer-review

60 Scopus citations


Modern and future surveys effectively provide a panchromatic view for large numbers of extragalactic objects. Consistently modeling these multiwavelength survey data is a critical but challenging task for extragalactic studies. The Code Investigating GALaxy Emission (cigale) is an efficient python code for spectral energy distribution (SED) fitting of galaxies and active galactic nuclei (AGNs). Recently, a major extension of cigale (named x-cigale) has been developed to account for AGN/galaxy X-ray emission and improve AGN modeling at UV-to-IR wavelengths. Here, we apply x-cigale to different samples, including Cosmological Evolution Survey (COSMOS) spectroscopic type 2 AGNs, Chandra Deep Field-South X-ray detected normal galaxies, Sloan Digital Sky Survey quasars, and COSMOS radio objects. From these tests, we identify several weaknesses of x-cigale and improve the code accordingly. These improvements are mainly related to AGN intrinsic X-ray anisotropy, X-ray binary emission, AGN accretion-disk SED shape, and AGN radio emission. These updates improve the fit quality and allow for new interpretation of the results, based on which we discuss physical implications. For example, we find that AGN intrinsic X-ray anisotropy is moderate, and can be modeled as LX(θ)∝ 1+cosθ, where θ is the viewing angle measured from the AGN axis. We merge the new code into the major branch of cigale, and publicly release this new version as cigale v2022.0 on

Original languageEnglish (US)
Article number192
JournalAstrophysical Journal
Issue number2
StatePublished - Mar 1 2022

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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