Results 31 to 40 of about 20,094 (246)

A Left and Right Truncated Schechter Luminosity Function for Quasars

Galaxies, 2017
The luminosity function for quasars (QSOs) is usually fitted by a Schechter function. The dependence of the number of quasars on the redshift, both in the low and high luminosity regions, requires the inclusion of a lower and upper boundary in the ...
Lorenzo Zaninetti
doaj   +1 more source

Dust grain growth in the interstellar medium of 5 [PDF]

, 2010
We investigate whether stellar dust sources i.e. asymptotic giant branch (AGB) stars and supernovae (SNe) can account for dust detected in 55 QSOs. SNe (but not AGB stars) may deliver enough heavy elements to fuel this growth.Comment: A&A, accepted.
Alton, Aravena, Barlow, Beelen, Benford, Bertoldi, Bertoldi, Bianchi, Blair, Borkowski, C. Gall, Carilli, Carilli, Carilli, Cherchneff, Cherchneff, D. Watson, Draine, Dunne, Dunne, Dunne, Dunne, Dwek, Dwek, Dwek, E. J. Murphy, Ercolano, Ferrarotti, Gomez, Gomez, Green, Haas, Hauser, Hirashita, J. Hjorth, J. S. Dunlop, Knudsen, Kotak, Krause, Lee, Leech, Leipski, M. J. Michałowski, Maiolino, Maiolino, Matsuura, Meikle, Michałowski, Michałowski, Michałowski, Michałowski, Morgan, Morgan, Nozawa, Perley, Petric, Polletta, Priddey, Priddey, Priddey, Rho, Rho, Ridgway, Riechers, Robson, Sakon, Salpeter, Sandstrom, Sibthorpe, Sloan, Stratta, Sugerman, Todini, Valiante, Veilleux, Vlahakis, Walter, Walter, Walter, Wang, Wang, Wang, Wang, Wesson, Wilson, Wu, Zafar, Zhukovska   +87 more
core   +2 more sources

Crossing the Rubicon of Reionization with z ∼ 5 QSOs

The Astrophysical Journal, 2023
One of the key open questions in cosmology is the nature of sources that completed cosmological hydrogen reionization at z ∼ 5.2. High- z primeval galaxies have been long considered the main drivers of reionization, with a minor role played by high- z ...
Andrea Grazian, Konstantina Boutsia, Emanuele Giallongo, Stefano Cristiani, Fabio Fontanot, Manuela Bischetti, Angela Bongiorno, Giorgio Calderone, Guido Cupani, Valentina D’Odorico, Chiara Feruglio, Fabrizio Fiore, Francesco Guarneri, Matteo Porru, Ivano Saccheo   +14 more
doaj   +1 more source

The QSO Evolution Derived from the HBQS and Other Complete QSO Surveys [PDF]

The Astronomical Journal, 1997
Submitted to AJ, 14 pages: LaTex file ass2pp4.sty, 2 tabels: ass2pp4.sty.
LA FRANCA, Fabio, Cristiani S.
openaire   +4 more sources

Optical variability of some quasars important to ICRF-Gaia CRF link [PDF]

Serbian Astronomical Journal, 2019
The Gaia optical observations started a few years ago. As a result, the Gaia Celestial Reference Frame (Gaia CRF) should replace the International CRF (ICRF).
Jovanović Miljana D.
doaj   +1 more source

On discrete-time models of network worm propagation generated by quadratic operators

Mathematical Modelling and Analysis, 2023
In this paper we consider the discrete-time dynamical systems generated by network worm propagation models based on the theory of quadratic stochastic operators(QSO).
Fatima Adilova, Uygun Jamilov, Andrejs Reinfelds   +2 more
doaj   +1 more source

X-ray and optical properties of Broad Absorption Line Quasars in the Canada-France-Hawaii Telescope Legacy Survey [PDF]

, 2010
We study the X-ray and optical properties of 16 Broad Absorption Line (BAL) quasars detected in about 3 degree square region common to the wide synoptic (W-1) component of the Canada-France-HawaiiTelescope Legacy Survey (CFHTLS) and the XMM Large Scale ...
Allen, Anderson, Arav, Arnaud, Becker, Bolzonella, Brotherton, C. S. Stalin, Dai, Dickey, DiPompeo, Fan, Gallagher, Gallagher, Gallagher, Ganguly, Ghosh, Gibson, Giustini, Goodrich, Green, Green, Green, Green, Gupta, Hazard, Hewett, Hines, Hutsemekers, Just, Knigge, Laor, Laor, Lavalley, Lonsdale, Mathur, Miller, Murray, Oke, P. Petitjean, Piconcelli, Pierre, Pierre, Priddey, R. Srianand, Reichard, Richards, Sabra, Schmidt, Shankar, Sharp, Sprayberry, Srianand, Srianand, Stalin, Steffen, Stern, Stern, Streblyanska, Tolea, Trump, Urrutia, Wampler, Wang, Weymann, Willott   +65 more
core   +3 more sources

ALMA High-frequency Long-baseline Campaign in 2019: Band 9 and 10 In-band and Band-to-band Observations Using ALMA’s Longest Baselines

The Astrophysical Journal Supplement Series, 2023
The Atacama Large Millimeter/submillimeter Array high-frequency long-baseline campaign in 2019 (HF-LBC-2019) was arranged to undertake band 9 (690 GHz) and 10 (850 GHz) observations using the longest 16 km baselines in order to explore calibration ...
Luke T. Maud, Yoshiharu Asaki, Hiroshi Nagai, Takafumi Tsukui, Akihiko Hirota, Edward B. Fomalont, William R. F. Dent, Satoko Takahashi, Neil Phillips   +8 more
doaj   +1 more source

The High A(V) Quasar Survey: Reddened quasi-stellar objects selected from optical/near-infrared photometry - II [PDF]

, 2015
Quasi-stellar objects (QSOs) whose spectral energy distributions (SEDs) are reddened by dust either in their host galaxies or in intervening absorber galaxies are to a large degree missed by optical color selection criteria like the one used by the Sloan
Fynbo, J. P. U., Geier, S., Kangas, T., Krogager, J. -K., Ledoux, C., Møller, P., Noterdaeme, P., Pursimo, T., Saturni, F. G., Smirnova, O., Venemans, B. P., Vestergaard, M.   +11 more
core   +2 more sources

The evolution of QSO spectra [PDF]

Monthly Notices of the Royal Astronomical Society, 1995
We find that the spectra of QSOs evolve: high redshift QSOs (z > 1.5) have lower equivalent width emission lines than low redshift QSOs (z < 0.5) with the same luminosities and radio properties.
Francis, Paul, Koratkar, Anuradha
openaire   +2 more sources