scholarly journals The radio spectra of reddened Two Micron All Sky Survey quasi-stellar objects: evidence for young radio jets

2012 ◽  
Vol 421 (3) ◽  
pp. 2223-2231 ◽  
Author(s):  
A. Georgakakis ◽  
M. Grossi ◽  
J. Afonso ◽  
A. M. Hopkins
Keyword(s):  
Stellar Objects ◽  
Radio Jets ◽  
Sky Survey ◽  
Quasi Stellar Objects

scholarly journals Fundamental differences in the radio properties of red and blue quasars: insight from the LOFAR Two-metre Sky Survey (LoTSS)

2020 ◽  
Vol 494 (3) ◽  
pp. 3061-3079 ◽  
Author(s):  
D J Rosario ◽  
V A Fawcett ◽  
L Klindt ◽  
D M Alexander ◽  
L K Morabito ◽  
...  
Keyword(s):  
Star Formation ◽  
Control Sample ◽  
Low Frequency ◽  
Galactic Nuclei ◽  
Sloan Digital Sky Survey ◽  
Stellar Objects ◽  
Radio Detection ◽  
Sky Survey ◽  
Quasi Stellar Objects ◽  
First Time

ABSTRACT Red quasi-stellar objects (QSOs) are a subset of the luminous end of the cosmic population of active galactic nuclei (AGNs), most of which are reddened by intervening dust along the line of sight towards their central engines. In recent work from our team, we developed a systematic technique to select red QSOs from the Sloan Digital Sky Survey, and demonstrated that they have distinctive radio properties using the Faint Images of the Radio Sky at Twenty centimetres radio survey. Here we expand our study using low-frequency radio data from the LOFAR Two-metre Sky Survey (LoTSS). With the improvement in depth that LoTSS offers, we confirm key results: Compared to a control sample of normal ‘blue’ QSOs matched in redshift and accretion power, red QSOs have a higher radio detection rate and a higher incidence of compact radio morphologies. For the first time, we also demonstrate that these differences arise primarily in sources of intermediate radio loudness: Radio-intermediate red QSOs are × 3 more common than typical QSOs, but the excess diminishes among the most radio-loud systems and the most radio-quiet systems in our study. We develop Monte Carlo simulations to explore whether differences in star formation could explain these results, and conclude that, while star formation is an important source of low-frequency emission among radio-quiet QSOs, a population of AGN-driven compact radio sources is the most likely cause for the distinct low-frequency radio properties of red QSOs. Our study substantiates the conclusion that fundamental differences must exist between the red and normal blue QSO populations.

scholarly journals Quasi-stellar objects acting as potential strong gravitational lenses in the SDSS-III BOSS survey

2019 ◽  
Vol 625 ◽  
pp. A56 ◽  
Author(s):  
Romain A. Meyer ◽  
Timothée Delubac ◽  
Jean-Paul Kneib ◽  
Frédéric Courbin
Keyword(s):  
Emission Line ◽  
Sloan Digital Sky Survey ◽  
Emission Lines ◽  
Gravitational Lenses ◽  
Stellar Objects ◽  
Sky Survey ◽  
Quasi Stellar Objects ◽  
Unique Approach ◽  
Algorithmic Search ◽  
Emission Line Galaxies

We present a sample of 12 quasi-stellar objects (QSOs) that potentially act as strong gravitational lenses on background emission line galaxies (ELG) or Lyman-α emitters (LAEs) selected through a systematic search of the 297 301 QSOs in the Sloan Digital Sky Survey (SDSS)-III Data Release 12. Candidates were identified by looking for compound spectra, where emission lines at a redshift larger than that of the quasar can be identified in the residuals after a QSO spectral template is subtracted from the observed spectra. The narrow diameter of BOSS fibers (2″) then ensures that the object responsible for the additional emission lines must lie close to the line of sight of the QSO and hence provides a high probability of lensing. Among the 12 candidates identified, nine have definite evidence for the presence of a background ELG identified by at least four higher-redshift nebular emission lines. The remaining three probable candidates present a strong asymmetrical emission line attributed to a background Lyman-α emitter (LAE). The QSO-ELG (QSO-LAE) lens candidates have QSO lens redshifts in the range 0.24 ≲ zQSO ≲ 0.66 (0.75 ≲ zQSO ≲ 1.23 ) and background galaxy redshifts in the range 0.48 ≲ zS, ELG ≲ 0.94 (2.17 ≲ zS, LAE ≲ 4.48). We show that the algorithmic search is complete at > 90% for QSO-ELG systems, whereas it falls at 40−60% for QSO-LAE, depending on the redshift of the source. Upon confirmation of the lensing nature of the systems, this sample may quadruple the number of known QSOs acting as strong lenses. We have determined the completeness of our search, which allows future studies to compute lensing probabilities of galaxies by QSOs and differentiate between different QSO models. Future imaging of the full sample and lens modelling offers a unique approach to study and constrain key properties of QSOs.

scholarly journals Further Identifications Of Radio Sources Between Declinations 0° And 20°

1966 ◽  
Vol 19 (3) ◽  
pp. 471 ◽  
Keyword(s):  
Radio Sources ◽  
Stellar Objects ◽  
Sky Survey ◽  
Position Data ◽  
Quasi Stellar Objects

Clarke, Bolton, and Shimmins (1966) have recently suggested identifications for 138 of the radio sources listed in the Parkes catalogue for declinations 0� to +20� (Day, Shimmins, Ekers, and Cole 1966). The identifications were made from inspection of the Palomar Sky Survey plates in areas 2' arc square centred on the catalogue positions. In general, identifications were suggested only for galaxies or possible quasi-stellar objects brighter than 17m . 5, in order to avoid the possibility of chance coincidences. Where objects fainter than 17m . 5 were suggested, position data of higher accuracy were available, due principally to unpublished measurements by Shimmins, Clarke, and Ekers with the 210 ft telescope.

scholarly journals New Optical Identifications from the Parkes 2700 MHz Resurvey of the ± 4° Declination Zone

1982 ◽  
Vol 35 (2) ◽  
pp. 207 ◽  
Author(s):  
Ann Savage ◽  
JG Bolton ◽  
Jenny Trett
Keyword(s):  
Radio Sources ◽  
Stellar Objects ◽  
Sky Survey ◽  
Quasi Stellar Objects ◽  
Optical Identifications

Identifications are suggested for 59 radio sources from the resurvey of declination zone �4�, 27 with galaxies and 32 with stellar objects; 19 of the latter are confirmed as quasi-stellar objects (QSOs). The identifications were made from the Palomar Sky Survey prints plus supplementary plates taken with the Palomar and U.K. Schmidt telescopes and the Anglo-Australian 3�9 m telescope.

Two Highly Polarized Quasi-stellar Objects Discovered by the Two Micron All Sky Survey

2000 ◽  
Vol 545 (1) ◽  
pp. L19-L22 ◽  
Author(s):  
Paul S. Smith ◽  
Gary D. Schmidt ◽  
Dean C. Hines ◽  
Roc M. Cutri ◽  
Brant O. Nelson
Keyword(s):  
Stellar Objects ◽  
Sky Survey ◽  
Quasi Stellar Objects

scholarly journals Identification of Extragalactic Radio Sources Between Declinations ?20° and ?44°

1965 ◽  
Vol 18 (6) ◽  
pp. 627 ◽  
Author(s):  
JG Bolton ◽  
Margaret E Clarke ◽  
RD Ekers
Keyword(s):  
Radio Sources ◽  
Stellar Objects ◽  
Extragalactic Radio Sources ◽  
Sky Survey ◽  
Quasi Stellar Objects

Identifications with extragalactic objects are suggested for 55 radio sources with declinations between _200 and _44�. The identifications are based on a search of the Palomar Sky Survey plates in the position of sources in the Parkes catalogue. Eight of the identifications are with suspected quasi-stellar objects and the remainder with galaxies. Finding charts are provided for the fainter obje~ts.

scholarly journals Accurate Positions and Identifications of 75 Radio Sources Between Declinations +20º and +27º

1968 ◽  
Vol 21 (6) ◽  
pp. 903 ◽  
Author(s):  
Jeannette K Merkelijn
Keyword(s):  
Radio Sources ◽  
Stellar Objects ◽  
Sky Survey ◽  
Quasi Stellar Objects ◽  
Estimated Error

Accurate positions have been obtained for 75 sources between declinations +20� and +27�. For most sources the estimated error is less than 15" arc in each coordinate. Identifications are suggested for 27 sources from inspection of the Palomar Sky survey prints near the new positions. Fourteen of the suggested identifications are galaxies and 13 are quasi. stellar objects.

scholarly journals New Optical Identifications from the Fourteenth Part of the Parkes 2700 MHz Survey: Declinations ?4° to ?15°, Right Ascensions 10h to 15h

1979 ◽  
Vol 32 (4) ◽  
pp. 415
Author(s):  
Ann Savage ◽  
JG Bolton
Keyword(s):  
Radio Sources ◽  
Stellar Objects ◽  
Sky Survey ◽  
Quasi Stellar Objects ◽  
Optical Identifications

Identifications are suggested for 36 radio sources from a survey of 0�247 sr of the southern sky, 14 with galaxies and 22 with possible quasi-stellar objects. The identifications were made from prints of the Palomar Sky Survey.

Optical Spectropolarimetry of Quasi‐stellar Objects Discovered by the Two‐Micron All Sky Survey

2003 ◽  
Vol 593 (2) ◽  
pp. 676-699 ◽  
Author(s):  
Paul S. Smith ◽  
Gary D. Schmidt ◽  
Dean C. Hines ◽  
Craig B. Foltz
Keyword(s):  
Stellar Objects ◽  
Sky Survey ◽  
Quasi Stellar Objects
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