Browsing by Author "Boquien, Médéric"

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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.
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    SDSS IV Manga: dependence of global and spatially resolved SFR–M∗ relations on galaxy properties
    (2018) Pan, Hsi An; Lin, Lihwai; Hsieh, Bau Ching; Sánchez, Sebastián F.; Ibarra Medel, Héctor; Boquien, Médéric; Lacerna Zambrano, Iván Andrés; Argudo Fernández, Maria; Bizyaev, Dmitry; Cano Díaz, Mariana
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    The Accretion History of AGN: The Spectral Energy Distributions of X-Ray-luminous Active Galactic Nuclei
    (2023) Auge, Connor; Sanders, David; Treister, Ezequiel; Urry, C. Megan; Kirkpatrick, Allison; Cappelluti, Nico; Ananna, Tonima Tasnim; Boquien, Médéric; Baloković, Mislav; Civano, Francesca; Coleman, Brandon; Ghosh, Aritra; Kartaltepe, Jeyhan; Koss, Michael; LaMassa, Stephanie; Marchesi, Stefano; Peca, Alessandro; Powell, Meredith; Trakhtenbrot, Benny; Turner, Tracey Jane
    Spectral energy distributions (SEDs) from X-ray to far-infrared (FIR) wavelengths are presented for a sample of 1246 X-ray-luminous active galactic nuclei (AGNs; L0.5–10 keV > 1043 erg s−1), with zspec < 1.2, selected from Stripe 82X, COSMOS, and GOODS-N/S. The rest-frame SEDs show a wide spread (∼2.5 dex) in the relative strengths of broad continuum features at X-ray, ultraviolet (UV), mid-infrared (MIR), and FIR wavelengths. A linear correlation (log–log slope of 0.7 ± 0.04) is found between LMIR and LX. There is significant scatter in the relation between the LUV and LX owing to heavy obscuration; however, the most luminous and unobscured AGNs show a linear correlation (log–log slope of 0.8 ± 0.06) in the relation above this scatter. The relation between LFIR and LX is predominantly flat, but with decreasing dispersion at LX > 1044 erg s−1. The ratio between the "galaxy-subtracted" bolometric luminosity and the intrinsic LX increases from a factor of ∼10 to 70 from log Lbol/(erg s−1) = 44.5 to 46.5. Characteristic SED shapes have been determined by grouping AGNs based on relative strengths of the UV and MIR emission. The average L1μm is constant for the majority of these SED shapes, while AGNs with the strongest UV and MIR emission have elevated L1μm, consistent with the AGN emission dominating their SEDs at optical and near-infrared wavelengths. A strong correlation is found between the SED shape and both the LX and Lbol, such that Lbol/LX = 20.4 ± 1.8, independent of the SED shape. This is consistent with an evolutionary scenario of increasing Lbol with decreasing obscuration as the AGN blows away circumnuclear gas.