Browsing by Author "Parra Tello, Miguel Agustín"

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    BASS XLIV. Morphological preferences of local hard X-ray selected AGNs
    (EDP Sciences, 2025) Parra Tello, Miguel Agustín; Bauer, Franz E.; Cicco, Demetra de; Doll, Goran; Koss, Michael; Treister, Ezequiel; Finlez, Carolina; Troncoso Balbiano, Marco Javier; Auge, Connor; Moral Castro, Ignacio del; Chung, Aeree; Gupta, Kriti K.; Kim, Jeein; Oh, Kyuseok; Ricci, Claudio; Ricci, Federica; Rojas, Alejandra; Caglar, Turgay; Harrison, Fiona; Powell, Meredith C.; Stern, Daniel; Trakhtenbrot, Benny; Urry, C. Megan
    We present detailed morphological classifications for the hosts of 1189 hard X-ray selected (14–195 keV) active galactic nuclei (AGNs) from the Swift-BAT 105-month catalog as part of the BAT AGN Spectroscopic Survey (BASS). BASS provides a powerful all-sky census of nearby AGNs, minimizing obscuration biases and providing a robust dataset for studying AGN-host galaxy connections. Classifications are based on a volunteer-based visual inspection workflow on the Zooniverse platform, adapted from the Galaxy Zoo DECaLS (GZD) project. Dual-contrast grz color composite images, generated from public surveys (e.g., NOAO Legacy Survey, Pan-STARRS, SDSS) and dedicated observations enabled key morphological features to be identified. Our analysis reveals that, with respect to a control sample of inactive galaxies, BASS AGN hosts show a deficiency of smooth elliptical galaxies (∼70%) and spiral galaxies with prominent arms (∼80%), while displaying an excess of mergers or disturbed systems (∼400%), and disk galaxies without a spiral structure (∼300%). These trends are found after controlling for redshift and i-band magnitude, which suggests a preference for AGN activity in gas-rich, dynamically disturbed environments or transitional disk systems. We also find a higher bar fraction among AGN hosts than in a control sample (∼50% vs. ∼30%). We further explore the relationships between AGN properties (e.g., X-ray luminosity, black hole mass, and Eddington ratio) and host morphology, and find that high-luminosity and high-accretion AGNs preferentially reside in smooth or point-like hosts. At the same time, lower-luminosity AGNs are more common in disk galaxies. These results underscore the importance of morphological studies in understanding the fueling and feedback mechanisms that drive AGN activity and their role in galaxy evolution. Our dataset provides a valuable benchmark for future multiwavelength surveys (e.g. LSST, Roman, and Euclid) and automated morphological classification efforts.
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    BASS. LIV. Physical Properties of AGN-hosting Galaxy Mergers from Multiwavelength SED Fitting
    (2025) Troncoso Balbiano, Marco Javier; Treister, Ezequiel; Rojas, Alejandra; Boquien, Médéric; Bauer, Franz; Koss, Michael J.; Assef, Roberto J.; Parra Tello, Miguel Agustín; Moral-Castro, Ignacio del; Ricci, Claudio; Dai, Sophia; Oh, Kyuseok; Ricci, Federica; Peca, Alessandro; Urry, C. Megan; Gupta, Kriti Kamal; Venturi, Giacomo; Signorini, Matilde; Mushotzky, Richard; Sanders, David
    Galaxy mergers are believed to play an important role in triggering rapid supermassive black hole (SMBH) growth. As merging nuclei approach each other, the physical properties of the participating galaxies and the associated SMBH growth are expected to evolve significantly. This study measures and characterizes these physical properties throughout the merger sequence. We constructed multiwavelength Spectral Energy Distributions (SEDs) from hard X-rays to the far-infrared (FIR) for a sample of 72 nearby Active Galactic Nuclei (AGN) host galaxies. The sample comprises 64 interacting systems, including single AGNs in mergers and dual AGNs, with nuclear separations 30 kpc, as well as eight isolated active galaxies with merging features. We carefully adapted available photometric measurements at each wavelength to account for their complex morphologies and varying spatial resolutions, to perform SED fitting using CIGALE, aimed to derive critical physical properties. Our results reveal that merging galaxies hosting AGN(s) show deviations from the star-forming main sequence, and a wide range of star formation rates (SFRs). Both AGN activity and star formation are significantly influenced by the merger process, but these effects are more prominent in major, mass ratios 4:1, interactions. We find that the projected nuclear separation is not a good tracer of the merger stage. Instead, morphological classification accurately assesses the merger progression. Based on this morphological analysis, late-stage mergers exhibit elevated SFRs (5.1), AGN luminosities (2.4), and nuclear obscuration (2.8) compared to earlier stages, supporting previous findings and reinforcing the link between merger-driven galaxy evolution and SMBH growth.