Charge coupled devices (CCD) photometry and long-term optical variability of gamma-ray-loud BL Lacertae object Mkn 421

2006 ◽  
Vol 15 (9) ◽  
pp. 2185-2192 ◽  
Author(s):  
Zhang Xiong ◽  
Zheng Yong-Gang ◽  
Zhang Hao-Jing ◽  
Hu Shao-Ming ◽  
Xie Zhao-Hua
Keyword(s):  
Gamma Ray ◽  
Optical Variability ◽  
Ccd Photometry ◽  
Bl Lacertae ◽  
Charge Coupled Devices

CCD Photometry and Optical Variability of Gamma-Ray-loud BL Lacertae Object OJ 287 in a Low, Fainter State

2007 ◽  
Vol 133 (5) ◽  
pp. 1995-2000 ◽  
Author(s):  
X. Zhang ◽  
G. Zhao ◽  
Y. G. Zheng ◽  
L. Ma ◽  
Z. H. Xie ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Optical Variability ◽  
Ccd Photometry ◽  
Bl Lacertae

VERITAS OBSERVATIONS OF RELATIVISTIC OUTFLOWS IN LOW- AND INTERMEDIATE-FREQUENCY-PEAKED BL LAC OBJECTS

2014 ◽  
Vol 28 ◽  
pp. 1460178
Author(s):  
◽  
HEIKE PROKOPH
Keyword(s):  
Gamma Ray ◽  
Intermediate Frequency ◽  
Bl Lac Objects ◽  
Bl Lacertae ◽  
Bl Lac ◽  
Bl Lacs ◽  
Gamma Ray Telescopes ◽  
Very High

The majority of blazars detected at very high energies (VHE; E > 100 GeV) are high-frequency-peaked BL Lac objects (HBLs). Low- and intermediate-frequency-peaked BL Lacs (LBLs/IBLs with synchrotron-peak frequencies in the infrared and optical regime) are generally more powerful, more luminous, and have a richer jet environment than HBLs. However, only a handful of these IBL and LBLs have been detected by ground-based gamma-ray telescopes, typically during high-flux states. The VERITAS array has been monitoring five known VHE LBLs/IBLs since 2009: 3C 66A, W Comae, PKS 1424+240, S5 0716+714 and BL Lacertae, with typical exposures of 5-10 hours per year. The results of these long-term observations are presented, including a bright, subhour-scale VHE flare of BL Lacertae in June 2011, the first low-state detections of 3C 66A and W Comae, and the detection and characterization of the IBL B2 1215+30.

scholarly journals The Long-Term Optical Variability of the BL Lacertae Object S5 0716+714: Evidence for a Precessing Jet

2005 ◽  
Vol 130 (4) ◽  
pp. 1466-1471 ◽  
Author(s):  
R. Nesci ◽  
E. Massaro ◽  
C. Rossi ◽  
S. Sclavi ◽  
M. Maesano ◽  
...  
Keyword(s):  
Optical Variability ◽  
Bl Lacertae

scholarly journals CCD photometry and long-term optical variability of PKS 2155-304

1996 ◽  
Vol 116 (2) ◽  
pp. 289-293 ◽  
Author(s):  
Y. H. Zhang ◽  
G. Z. Xie
Keyword(s):  
Optical Variability ◽  
Ccd Photometry

CCD Photometry and Optical Variability of the BL Lacertae Object H0323+022

2008 ◽  
Vol 174 (1) ◽  
pp. 111-116 ◽  
Author(s):  
X. Zhang ◽  
Y. G. Zheng ◽  
H. J. Zhang ◽  
S. M. Hu
Keyword(s):  
Optical Variability ◽  
Ccd Photometry ◽  
Bl Lacertae

scholarly journals Long-term and intra-day variability of BL Lacertae since the last great outburst

2006 ◽  
Vol 2 (S238) ◽  
pp. 419-420 ◽  
Author(s):  
Maria G. Nikolashvili ◽  
Omar M. Kurtanidze
Keyword(s):  
Ccd Camera ◽  
Active Phase ◽  
Optical Variability ◽  
Optical Photometry ◽  
Bl Lacertae ◽  
Maximum Variation

AbstractWe present the results of optical photometry of BL Lacertae carried out using ST-6 CCD camera attached to the Newtonian focus of the 70 cm meniscus telescope of Abastumani Observatory. On the basis of observations conducted since August 1997 during more than 550 nights about 17000 frames were collected. They have been reduced using Daophot II.It has been shown that optical variability of BL Lacertae is very complex. The maximum variation was observed at long-term scale and is equal to equals to 3.0 mag (rms=0.03) in B band, while the variation in V and R bands are within 2.71 mag (0.02) and 2.53 mag (0.01), respectively. This means that variations are larger at shorter wavelength or the object become bluer in the active phase. It were also demonstrated that BL Lacertae shows intra-day variability within 0.30 mag (0.02), while intra-hour variability within 0.10 mag (0.01) magnitudes.

scholarly journals VERITAS Long Term Monitoring of Gamma-Ray Emission from the BL Lacertae Object

2017 ◽  
Author(s):  
Anushka Abeysekara ◽  
Keyword(s):  
Gamma Ray ◽  
Bl Lacertae ◽  
Long Term Monitoring ◽  
Gamma Ray Emission ◽  
Term Monitoring

THE LONG-TERM OPTICAL VARIABILITY PROPERTIES OF GAMMA-RAY BLAZAR 3C 273

2006 ◽  
Vol 15 (02) ◽  
pp. 261-272 ◽  
Author(s):  
BEN-ZHONG DAI ◽  
BIN-KAI ZHANG ◽  
YANG XIANG ◽  
JIAN-PING YANG ◽  
LIN LIN ◽  
...  
Keyword(s):  
Correlation Function ◽  
Gamma Ray ◽  
The Other ◽  
Optical Variability ◽  
X Ray ◽  
Self Consistent ◽  
Data Points ◽  
Quasar 3C 273 ◽  
Good Agreement

We compile all the available optical B band data for the quasar 3C 273 from 1887 to 2001 from the literature, and obtain 1,890 data points. Using these data, we analyze the light curve properties by means of the Jurkevich method and the discrete correlation function (DCF) method. The analysis results of the two methods are self consistent; the cross-checked variability period is 13.51 years. The 13.51-year period variation in the optical band is in good agreement with the previous results in the optical and X-ray bands. However, the other claimed periods of the quasar 3C 273 are not confirmed in our work.

scholarly journals Spectral Modeling of Flares in Long-term Gamma-Ray Light Curve of PKS 0903-57

2021 ◽  
Vol 922 (2) ◽  
pp. 160
Author(s):  
Sandeep Kumar Mondal ◽  
Raj Prince ◽  
Nayantara Gupta ◽  
Avik Kumar Das
Keyword(s):  
Gamma Ray ◽  
Spectral Energy ◽  
Emission Region ◽  
Multiple Time ◽  
Emission Model ◽  
X Rays ◽  
Large Area ◽  
Bl Lacertae ◽  
First Time

Abstract A detailed study of the BL Lacertae PKS 0903-57 has been done for the first time with 12 yr of Fermi Large Area Telescope data. We have identified two bright gamma-ray flares in 2018 and 2020. Many substructures were observed during multiple time binning of these flares. We performed a detailed temporal and spectral study on all the substructures separately. A single-zone emission model is used for time-dependent leptonic modeling of the multiwavelength spectral energy distributions. Our estimated values of variability timescale, magnetic field in the emission region, and the jet power obtained from leptonic modeling of PKS 0903-57 are presented in this work. Currently, we have a minimal number of observations in X-rays and other bands. Hence, further simultaneous multiwavelength monitoring of this source is required to have a better understanding of the physical processes occurring in the jet of the blazar PKS 0903-57.

scholarly journals Multiband optical variability studies of BL Lacertae

2015 ◽  
Vol 450 (1) ◽  
pp. 541-551 ◽  
Author(s):  
Aditi Agarwal ◽  
Alok C. Gupta
Keyword(s):  
Optical Variability ◽  
Bl Lacertae
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