Six z~2-3 quasars with extreme LoBAL outflows and weak UV lines are interpreted as weak-emission-line quasars emerging from dust cocoons via disc winds that shatter grains and produce steeper extinction.
Growing supermassive black holes in the late stages of galaxy mergers are heavily obscured
5 Pith papers cite this work. Polarity classification is still indexing.
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Pith papers citing it
abstract
Mergers of galaxies are thought to cause significant gas inflows to the inner parsecs, which can activate rapid accretion onto supermassive black holes (SMBHs), giving rise to Active Galactic Nuclei (AGN). During a significant fraction of this process, SMBHs are predicted to be enshrouded by gas and dust. Studying 52 galactic nuclei in infrared-selected local Luminous and Ultra-luminous infrared galaxies in different merger stages in the hard X-ray band, where radiation is less affected by absorption, we find that the amount of material around SMBHs increases during the last phases of the merger. We find that the fraction of Compton-thick (CT, $N_{\rm\,H}\geq 10^{24}\rm\,cm^{-2}$) AGN in late merger galaxies is higher ($f_{\rm\,CT}=65^{+12}_{-13}\%$) than in local hard X-ray selected AGN ($f_{\rm\,CT}=27\pm 4\%$), and that obscuration reaches its maximum when the nuclei of the two merging galaxies are at a projected distance of $D_{12}\simeq0.4-10.8$ kiloparsecs ($f_{\rm\,CT}=77_{-17}^{+13}\%$). We also find that all AGN of our sample in late merger galaxies have $N_{\rm\,H}> 10^{23}\rm\,cm^{-2}$, which implies that the obscuring material covers $95^{+4}_{-8}\%$ of the X-ray source. These observations show that the material is most effectively funnelled from the galactic scale to the inner tens of parsecs during the late stages of galaxy mergers, and that the close environment of SMBHs in advanced mergers is richer in gas and dust with respect to that of SMBHs in isolated galaxies, and cannot be explained by the classical AGN unification model in which the torus is responsible for the obscuration.
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Bayesian continuum fitting of 66 LRDs shows the BH* model fits ~6% best, rising to ~40% under AGN-disfavoring priors, with most objects stellar/AGN-dominated and possible evolutionary trends.
VLBI imaging detects a compact radio source with Tb > 10^7 K and flat spectrum in the northern core of UGC 2369S, confirming a buried low-luminosity AGN.
Multi-scale radio observations of 15 local U/LIRGs decompose emission to show nuclear components contribute ~50% on average while diffuse SF-related emission dominates ~80% of total power, with radio excess linked to AGN rather than boosted star formation.
Overview chapter summarizing traditional orientation-based and radiation-regulated unification models for AGN, including evolutionary aspects and changing-look AGN.
citing papers explorer
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Extreme outflow velocities and weak UV emission lines indicate quasars shedding their dust cocoons
Six z~2-3 quasars with extreme LoBAL outflows and weak UV lines are interpreted as weak-emission-line quasars emerging from dust cocoons via disc winds that shatter grains and produce steeper extinction.
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Between Degeneracy and Evolution: UV-to-optical Insights into the BH$^*$ Model in Little Red Dots
Bayesian continuum fitting of 66 LRDs shows the BH* model fits ~6% best, rising to ~40% under AGN-disfavoring priors, with most objects stellar/AGN-dominated and possible evolutionary trends.
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Direct VLBI evidence for a buried AGN in the triple-merger LIRG UGC 2369S
VLBI imaging detects a compact radio source with Tb > 10^7 K and flat spectrum in the northern core of UGC 2369S, confirming a buried low-luminosity AGN.
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The PARADIGM Project II: Characterising Nuclear and Diffuse Radio Components in Local U/LIRGs
Multi-scale radio observations of 15 local U/LIRGs decompose emission to show nuclear components contribute ~50% on average while diffuse SF-related emission dominates ~80% of total power, with radio excess linked to AGN rather than boosted star formation.
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Unification models of Active Galactic Nuclei
Overview chapter summarizing traditional orientation-based and radiation-regulated unification models for AGN, including evolutionary aspects and changing-look AGN.