Results 101 to 110 of about 272 (130)
The multiwavelength behaviour of BL Lacertae explained by a wiggling filamentary jet
Raiteri C.
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Annual Review of Astronomy and Astrophysics, 1976
Although discovered relatively recently, the class of objects of which BL Lac is the prototype is currently the subject of very active study. The peculiar character of these objects became apparent after the identification (Schmitt 1968) of the "variable star" BL Lacertae with the unusual radio source VRO 42.22.01 (MacLeod & Andrew 1968) and subsequent
S L O'Dell, P A Strittmatter
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Although discovered relatively recently, the class of objects of which BL Lac is the prototype is currently the subject of very active study. The peculiar character of these objects became apparent after the identification (Schmitt 1968) of the "variable star" BL Lacertae with the unusual radio source VRO 42.22.01 (MacLeod & Andrew 1968) and subsequent
S L O'Dell, P A Strittmatter
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The ROSAT X-ray spectra of BL Lacertae objects [PDF]
Monthly Notices of the Royal Astronomical Society, 1996 We have analyzed the X-ray spectra of all BL Lacs observed (as pointed or serendipitous sources) by ROSAT. Spectral indices were obtained from the hardness ratios given in the WGA catalogue, a large list of X-ray sources generated from all the ROSAT PSPC pointed observations. The selection of the objects was done by cross-correlating the first revision
P Padovani, P Giommi, Padovani Paolo
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Scientific American, 1977
The properties of BL Lacertae objects are discussed including their spectra, variability, and brightness. The historical development of observation, and the conclusion that these objects are possibly quasar-related objects rather than variable stars as originally supposed are treated.
Michael J. Disney, Philippe Véron
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The properties of BL Lacertae objects are discussed including their spectra, variability, and brightness. The historical development of observation, and the conclusion that these objects are possibly quasar-related objects rather than variable stars as originally supposed are treated.
Michael J. Disney, Philippe Véron
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?Einstein? observations of BL Lacertae objects
Space Science Reviews, 1981Nine fields containing BL Lacertae objects have been observed with the Imaging Proportional Counter of the “Einstein” Observatory. We have detected seven BL Lacertae objects and eight serendipitous sources. In this paper we give a full account of the time variability of 3C 66A, by comparing its behaviour at X-ray energies and at the other frequencies ...
D. Maccagni, M. Tarenghi
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VHE observations of BL Lacertae objects: 1995–2000
New Astronomy Reviews, 2004 The results of observations of 29 BL Lacertae objects taken with the Whipple Observatory 10 m gamma-ray Telescope between 1995 and 2000 are presented.
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BeppoSAX observations of 1-Jy BL Lacertae objects -- II [PDF]
Monthly Notices of the Royal Astronomical Society, 2004 We present new BeppoSAX LECS and MECS observations, covering the energy range 0.1 - 10 keV (observer's frame), of four BL Lacertae objects selected from the 1 Jy sample. All sources display a flat (alpha_x ~ 0.7) X-ray spectrum, which we interpret as inverse Compton emission.
P Padovani, L Costamante, P Giommi
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NGC1275: a BL Lacertae object?
Nature, 1978NGC1275 APPEARS in Seyfert's list1 of galaxies which have many high excitation emission lines in the nuclei. Seyfert remarks that all the emission lines in these galaxies are unusually broad. Khachikian and Weedman2 separated the Seyfert galaxies into two classes In class 1, the Balmer lines are broader than the forbidden lines; in class 2, the ...
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On the close environment of BL Lacertae objects
Nature, 1990THE local environment of BL Lacertae objects, which resemble quasars but lack emission lines, is poorly understood. In the few cases where the surrounding nebulosity has been studied in detail, it is consistent with the presence of a giant elliptical galaxy1, but the evidence that the BL Lac and the putative galaxy are physically associated rests ...
Renato Falomo +2 more
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Detection of microvariability for BL Lacertae objects
Nature, 1989Large-amplitude, rapid optical variability is a well-known identifying characteristic for BL Lacertae objects ('blazars'). Although large-amplitude variations on timescales ranging from days to decades have been well documented1, considerable controversy surrounds the nature of microvariability, that is, optical variations on timescales significantly ...
H. R. Miller +2 more
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