New DESI Data Confirms Universe's Large-Scale Homogeneity, Supporting Standard Cosmological Model
The Euclid Collaboration has published findings from its first Quick Data Release (Q1) showing that active galactic nuclei (AGN) emission significantly distorts estimates of galaxy physical properties derived from spectral energy distribution (SED) fitting. When AGN light is not properly accounted for in SED modeling, key parameters such as stellar mass, star formation rate, and dust attenuation can be systematically over- or underestimated. This has important implications for large-scale galaxy surveys, as unaccounted AGN contamination could introduce biases into statistical studies of galaxy evolution.
The Euclid Collaboration's Q1 data release includes a detailed investigation into how AGN emission affects the recovery of galaxy physical properties through SED fitting, a standard technique used to infer stellar masses, star formation rates, and other characteristics from multi-wavelength photometry. The study finds that AGN contributions to the overall spectral energy distribution can mimic or obscure stellar population signatures, leading to systematic errors when AGN components are not included in the fitting procedure. The team analyzed a sample of galaxies and AGN hosts identified in the Euclid Q1 fields, comparing SED-derived properties with and without AGN modeling components. Results indicate that stellar masses and star formation rates are among the most affected parameters, with biases that vary depending on AGN luminosity relative to the host galaxy. The findings underscore the necessity of incorporating AGN templates or hybrid models in SED fitting pipelines for surveys like Euclid, which will observe hundreds of millions of galaxies over its mission lifetime. Properly handling AGN contamination is critical to ensuring the scientific integrity of Euclid's galaxy evolution and cosmological studies.
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- arXiv astro-phCenter
$\delta$-CDM: A Minimal Deformation of $\Lambda$CDM with Scalar Field Reconstruction
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