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Related papers: The 2dF BL Lac Survey II

200 papers

Six BL Lac objects from the complete 1 Jy radio-selected sample of 34 objects were observed in Cycle 5 with the HST WFPC2 camera to an equivalent limiting flux of mu_I~26 mag/arcsec^2. Here we report results for the second half of this…

A search of the Two Micron All Sky Survey and Sloan Digital Sky Survey reveals 36 previously unknown high proper motion objects with J<17. Their red-optical colors indicate that 27 are M dwarfs, 8 are early-type L dwarfs, and 1 is a…

Astrophysics · Physics 2009-11-13 Scott S. Sheppard , Michael C. Cushing

We report the discovery of twenty-one hitherto unknown bright southern ultracool dwarfs with spectral types in the range M7 to L5.5, together with new observations of a further three late M dwarfs previously confirmed. Three more objects…

We present updated and complete radio, optical and X-ray data for BL Lacs in the Einstein Medium Sensitivity Survey (EMSS). The complete "M91" sample first presented in Morris et al. is updated to include 26 BL Lacs in total and we define a…

Astrophysics · Physics 2009-10-31 T. A. Rector , J. T. Stocke , E. S. Perlman , S. L. Morris , I. M. Gioia

We present a radio/optical study of a sample of BL Lac objects at arcsecond and milliarcsecond resolution. The sample consists of 30 nearby (z<0.2) BL Lacs, mostly X-ray selected. These nearby objects are weak in the radio, yet we have…

Astrophysics · Physics 2007-05-23 M. Giroletti , G. Giovannini , G. B. Taylor , R. Falomo

We present the final spectroscopic QSO catalogue from the 2dF-SDSS LRG and QSO (2SLAQ) Survey. This is a deep, 18<g<21.85 (extinction corrected), sample aimed at probing in detail the faint end of the broad line AGN luminosity distribution…

We report the discovery of 27 quasars with redshifts between 3.58 and 4.49. The objects were identified as high-redshift candidates based on their colors in Sloan Digital Sky Survey commissioning data. The redshifts were confirmed with low…

Context. The study of BL Lac objects (BLL) detected in gamma-rays gives insights on the acceleration mechanisms in play in such systems and is also a valuable tool to constrain the density of the extragalactic background light. As their…

High Energy Astrophysical Phenomena · Physics 2014-05-08 Santiago Pita , Paolo Goldoni , Catherine Boisson , Jean-Philippe Lenain , Michael Punch , Lucie Gérard , François Hammer , Lex Kaper , Hélène Sol

A search of more than 3,000 square degrees of high latitude sky by the Sloan Digital Sky Survey has yielded 251 faint high-latitude carbon stars (FHLCs), the large majority previously uncataloged. We present homogeneous spectroscopy,…

We present radio observations for 29 southern Seyfert galaxies selected from a volume limited sample with cz<3600 km s^-1, and declination delta<0degr. Objects with declination -30degr<delta<0degr were observed with the Very Large Array…

Astrophysics · Physics 2009-10-31 R. Morganti , Z. I. Tsvetanov , J. Gallimore , M. G. Allen

High energy observations of extreme BL Lac objects, such as 1ES 0229+200 or 1ES 0347-121, recently focused interest both for blazar and jet physics and for the implication on the extragalactic background light and intergalactic magnetic…

High Energy Astrophysical Phenomena · Physics 2015-06-25 Giacomo Bonnoli , Fabrizio Tavecchio , Gabriele Ghisellini , Tullia Sbarrato

We report on optical spectroscopy obtained at the 10.4m Gran Telescopio Canarias of 28 Fermi gamma-ray sources that completes the study of a sample of 60 targets of unidentified objects for which the detection of an X-ray and/or radio…

Astrophysics of Galaxies · Physics 2019-05-01 Simona Paiano , Renato Falomo , Aldo Treves , Alberto Franceschini , Riccardo Scarpa

We present HST observations of seven unusual objects from the HST ``snapshot survey'' of BL Lac objects, of which four are gravitational lens candidates. In three cases a double point sources is observed: 0033+595, with 1.58 arcsec…

Astrophysics · Physics 2009-10-31 R. Scarpa , C. M. Urry , R. Falomo , J. E. Pesce , R. Webster , M. O'Dowd , A. Treves

We investigate the spectroscopic optical properties of gamma-ray sources detected with high significance above 50 GeV in the Third Catalog of Hard Fermi-LAT Sources (3FHL) and that are good candidates as TeV emitters. We focus on the 91…

Astrophysics of Galaxies · Physics 2020-07-08 Simona Paiano , Renato Falomo , Aldo Treves , Riccardo Scarpa

BL Lac objects are known to have compact jets inclined to our line of sight at a small angle, showing prominent radio emission. Two radio-weak BL Lac candidates with no counterparts in current radio surveys were recently reported by Massaro…

Astrophysics of Galaxies · Physics 2018-10-17 Hong-Min Cao , Sándor Frey , Krisztina É. Gabányi , Jun Yang , Lang Cui , Xiao-Yu Hong , Tao An

High-resolution images of 7 newly identified BL Lac objects (among them one BL Lac candidate) at z < 0.2 from the Einstein Slew Survey are presented for the first time. In all cases we were able to resolve the host galaxy. Our 2-dimensional…

Astrophysics · Physics 2007-05-23 J. Heidt , K. Nilsson , A. Sillanpaeae , L. O. Takalo , T. Pursimo

We present the soft X-ray (0.1--2.4 keV) properties of a complete sample of 88 southern radio sources derived from the Wall \& Peacock 2-Jy sample. It comprises 68 radio galaxies, 18 quasars and 2 BL Lac objects. Whereas both BL Lac objects…

We present 5 filter photometry of 21 carbon stars, 15 asteroids, 15 cataclysmic variables, 6 metal-poor stars, 5 Cepheids, 1775 field stars, blue horizontal branch (BHB) stars and RR Lyrae stars in the globular clusters M 15 and M 2, two…

Astrophysics · Physics 2015-06-24 Kevin Krisciunas , Bruce Margon , Paula Szkody

Due to their almost featureless optical/UV spectra, it is challenging to measure the redshifts of BL Lacs. As a result, about 50% of gamma-ray BL Lacs lack a firm measurement of this property, which is fundamental for population studies,…