New Eyes for Galaxies Investigation

D’Onofrio, M.; Zaggia, S.; Rampazzo, R.; Vallenari, A.; Gilmore, G.; Marziani, Paola; Stiavelli, M.; Calzetti, Daniela; Bianchi, Luciana; Trinchieri, G.; Bland-Hawthorn, J.; Kaifu, Norio; Combes, F.; Moss, D.; Paturel, G.

doi:10.1007/978-3-319-31006-0_9

Cited by 2 publications

(1 citation statement)

References 97 publications

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“…Quasars represent the most luminous stable sources in the Universe (e.g., D'Onofrio et al, 2012D'Onofrio et al, , 2016, and it is disturbing that some basic issues still remain unsolved in spite of decade-long efforts (e.g., Sulentic et al, 2012;Antonucci, 2013, and references therein). The overall most pressing issue is perhaps the inability to connect physical parameters (such as black hole mass; Marziani and Sulentic, 2012;Shen, 2013;Peterson, 2014, for recent reviews) to the observational properties of individual quasars.…”

Section: Introductionmentioning

confidence: 99%

The Phylogeny of Quasars and the Ontogeny of Their Central Black Holes

Fraix-Burnet

Marziani

D’Onofrio

et al. 2017

Front. Astron. Space Sci.

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The connection between multifrequency quasar observational and physical parameters related to accretion processes is still open to debate. In the last 20 year, Eigenvector 1-based approaches developed since the early papers by Boroson and Green (1992) and Sulentic et al. (2000b) have been proven to be a remarkably powerful tool to investigate this issue, and have led to the definition of a quasar "main sequence." In this paper we perform a cladistic analysis on two samples of 215 and 85 low-z quasars (z 0.7) which were studied in several previous works and which offer a satisfactory coverage of the Eigenvector 1-derived main sequence. The data encompass accurate measurements of observational parameters which represent key aspects associated with the structural diversity of quasars. Cladistics is able to group sources radiating at higher Eddington ratios, as well as to separate radio-quiet (RQ) and radio-loud (RL) quasars. The analysis suggests a black hole mass threshold for powerful radio emission and also properly distinguishes core-dominated and lobe-dominated quasars, in accordance with the basic tenet of RL unification schemes. Considering that black hole mass provides a sort of "arrow of time" of nuclear activity, a phylogenetic interpretation becomes possible if cladistic trees are rooted on black hole mass: the ontogeny of black holes is represented by their monotonic increase in mass. More massive radio-quiet Population B sources at low-z become a more evolved counterpart of Population A i.e., wind dominated sources to which the "local" Narrow-Line Seyfert 1s belong.

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Section: Introductionmentioning

confidence: 99%

The Phylogeny of Quasars and the Ontogeny of Their Central Black Holes

Fraix-Burnet

Marziani

D’Onofrio

et al. 2017

Front. Astron. Space Sci.

Self Cite

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Hot Stars in the GALEX Ultraviolet Sky Surveys (GUVcat_AISxSDSS_HS) and the Binary Fraction of Hot Evolved Stars

Bianchi

2024

ApJS

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We present a catalog of 71,364 pointlike UV sources with Sloan Digital Sky Survey (SDSS) photometry and GALEX far-UV (FUV)−near-UV (NUV) ≤0.1 mag. The limit corresponds to stellar T eff ≳15,000−20,000 K, slightly depending on gravity but nearly reddening independent for Milky Way−type dust. Most sources are hot white dwarfs (WDs) and subdwarfs. Comparing the spectral energy distribution (SED; GALEX FUV, NUV, SDSS u,g,r,i,z) of 35,294 sources having good photometry with colors of stellar models and known objects, we identify 12,404 ± 1267 1871 binary hot-compact stars with a cooler, less-evolved companion (with a possible 8%–15% contamination by low-redshift QSOs), and 22,848 ± 3853 1267 single-star candidates. Single-star counts are an upper limit because pairs of similar stars have single-star-like SEDs, and hot WDs with main-sequence companions of certain types (depending on the WD’s radius) are missed or counted as single in the available wavelength range and selection. The catalog offers unique leverage for identifying hot WDs, elusive at longer wavelengths when a cooler, larger companion dominates optical–IR fluxes: 51% of the binary-star and 20% of the single-star candidates are previously unknown objects. Gaia DR3 provides a parallax with error ≤20% for 34% of the binary-star candidates and 45% of single-star candidates, allowing T eff, E B−V , radius, and L bol to be derived from SED analysis. The binary-candidate sample usefully expands the overall current binary-WD census to subpopulations elusive to Gaia and to other searches. The binary fraction among this specific sample of hot compact objects, albeit with the mentioned biases, b f ≳ 46%, compared with that of their progenitors (>80%–50% for mass range 8−1M ⊙, according to M. Moe), implies a lower merging rate than found for massive stars by H. Sana et al.

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New Eyes for Galaxies Investigation

Cited by 2 publications

References 97 publications

The Phylogeny of Quasars and the Ontogeny of Their Central Black Holes

The Phylogeny of Quasars and the Ontogeny of Their Central Black Holes

Hot Stars in the GALEX Ultraviolet Sky Surveys (GUVcat_AISxSDSS_HS) and the Binary Fraction of Hot Evolved Stars

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