Add to ORKGAbstract. Seven BL Lac objects have been photometri-cally observed in an eort to study the dierence of optical intraday variability between the radio-selected BL Lac ob-jects (RBLs) and X-ray-selected BL Lac objects (XBLs). The objects we observed are selected arbitrarily. They are four RBLs, PKS 0735+178, PKS 0754+101, OJ 287 and BL Lac, and three XBLs, H 0323+022, H 0548−322 and H 2154−304. During the observation all of them exhibited microvariation, and H 0323+022 and H 0548−322 some-times showed brightness oscillation. PKS 0735+178 and BL Lac were in their faint states and not very active. It seems that RBLs do not show microvariability more fre-quently than XBLs. Key words: BL Lacertae objects: general | galaxies: photometry 1
Aims. We present an XMM–Newton catalogue of BL Lac X-ray, optical, and UV properties based on cross-...
We present the results of recent BeppoSAX observations of the two BL Lac objects OJ 287 and MS 1458...
Abstract. | The paper presents the rst evidence for long-term optical variability and colour behavio...
Seven BL Lac objects have been photometrically observed in an effort to study the difference of opt...
Observations at millimetre wavelengths are presented for a representative sample of 22 X-ray-selecte...
We investigate the nature of the BL Lac candidates in the northern part of the 2BL sample (Londish e...
ROSAT data as well as archival radio and optical data are used for a broad band study of a large gro...
Abstract. | We present V RcIc Johnson-Cousins magnitudes of eld comparison stars for twelve BL Lacer...
Submitted to: Astron. Astrophys. Abstract: We present a new well defined sample of BL Lac objects s...
The results of optical photometric $(BVRI)$ monitoring of three BL Lac objects over a time interval ...
Many properties of BL Lacs have become explicable in terms of the "relativistic beaming" hypothesis ...
BL Lacertae objects are the most extreme members of a class of objects known as Active Galactic Nucl...
We present single-epoch infrared photometry of two complete samples of BL Lacertae objects, one radi...
SUMMARY: We present the radio detection of 18 BL Lac objects from our sur-vey of over 575 deg2 of sk...
We report on seven nights of optical observation taken over a two-week period, and the resultant ana...
Aims. We present an XMM–Newton catalogue of BL Lac X-ray, optical, and UV properties based on cross-...
We present the results of recent BeppoSAX observations of the two BL Lac objects OJ 287 and MS 1458...
Abstract. | The paper presents the rst evidence for long-term optical variability and colour behavio...
Seven BL Lac objects have been photometrically observed in an effort to study the difference of opt...
Observations at millimetre wavelengths are presented for a representative sample of 22 X-ray-selecte...
We investigate the nature of the BL Lac candidates in the northern part of the 2BL sample (Londish e...
ROSAT data as well as archival radio and optical data are used for a broad band study of a large gro...
Abstract. | We present V RcIc Johnson-Cousins magnitudes of eld comparison stars for twelve BL Lacer...
Submitted to: Astron. Astrophys. Abstract: We present a new well defined sample of BL Lac objects s...
The results of optical photometric $(BVRI)$ monitoring of three BL Lac objects over a time interval ...
Many properties of BL Lacs have become explicable in terms of the "relativistic beaming" hypothesis ...
BL Lacertae objects are the most extreme members of a class of objects known as Active Galactic Nucl...
We present single-epoch infrared photometry of two complete samples of BL Lacertae objects, one radi...
SUMMARY: We present the radio detection of 18 BL Lac objects from our sur-vey of over 575 deg2 of sk...
We report on seven nights of optical observation taken over a two-week period, and the resultant ana...
Aims. We present an XMM–Newton catalogue of BL Lac X-ray, optical, and UV properties based on cross-...
We present the results of recent BeppoSAX observations of the two BL Lac objects OJ 287 and MS 1458...
Abstract. | The paper presents the rst evidence for long-term optical variability and colour behavio...