Reconstructing f(R) theory according to holographic dark energy

AbstractIn this Letter a connection between the holographic dark energy model and the f(R) theory is established. We treat the f(R) theory as an effective description for the holographic dark energy and reconstruct the function f(R) with the parameter c>1, c=1 and c<1, respectively. We show the distinctive behavior of each cases realized in f(R) theory, especially for the future evolution

Color Behavior Of BL Lacertae Object OJ 287 During Optical Outburst

This paper aims to study the color behavior of the BL Lac object OJ 287 during optical outburst. According to the revisit of the data from the OJ-94 monitoring project and the analysis the data obtained with the 60/90 cm Schmidt Telescope of NAOC, we found a bluer-when-brighter chromatism in this object. The amplitude of variation tends to decrease with the decrease of frequency. These results are consistent with the shock-in-jet model. We made some simulations and confirmed that both amplitude difference and time delay between variations at different wavelengths can result in the phenomenon of bluer-when-brighter. Our observations confirmed that OJ 287 underwent a double-peaked outburst after about 12 years from 1996, which provides further evidence for the binary black hole model in this object.Comment: 25 pages, 13 figure