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INAF – Osservatorio Astronomico di Trieste, Trieste, Italy
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Abstract Reference: 30815
Identifier: P1.6
Presentation: Poster presentation
Key Theme: 1 Reduction and Analysis Algorithms for Large Databases and Vice-versa

QSFit: a new software for AGN optical spectral analysis

Calderone Giorgio

I will present QSFit, a new software to automatically perform the analysis of Active Galactic Nuclei (AGN) optical spectra. The software provides estimates of: AGN continuum luminosities and slopes at 5 different rest frame wavelengths host galaxy luminosities (for sources with z<~0.8) luminosities, widths and velocity offsets of 20 emission lines (Halpha, Hbeta, MgII, OIII, CIV, etc...) and luminosities of iron blended lines at optical and UV wavelengths. The purpose is similar to previous works on AGN spectral analysis, but the analysis follows a different approach: instead of focusing on a single emission line and estimate the continuum in the surrounding region, we fit all the components simultaneously using an AGN continuum which extends over the entire available spectrum. The whole fitting process is customizable for specific needs and data sources. We adapted it to analyze the SDSS optical spectra and ran the code over ~80,000 specra of Type 1 AGN at z<2. Our results are generally in very good agreement with those available in literature where the considered quantitites are directly comparable (e.g. the continuum luminosities). The emission line decomposition, however, strongly depend on the adopted algorithm, and the comparison of our estimates with previous results shows significant scatter. QSFit is our first attempt to provide a standardized way to analyze the AGN optical spectra in a similar way as other software (such as XSPEC) are used to analyze X-ray data. The ultimate purpose of QSFit is to allow astronomers to run a standardized recipe to analyze the data, in a simple, replicable and shareable way. Moreover, it allows users to fine tune the analysis for specific needs. The QSFit code will be released as free software under the GPL license. Also, all data in our AGN catalog, as well as the plots of spectrum with best fitting model and residuals, will be publicly available online.