New method of eclipse mapping and an application to HT Cas in the 2017 superoutburst

Abstract

We have developed a new eclipse mapping method with Total Variation Minimization (TVM). TVM uses a concept of sparse modeling, which recovers information from sparse data. TVM sets a summation of difference in the brightness of adjacent elements in a map to be sparse. We included this concept to the eclipse mapping method and evaluated consistency of the reconstruction of the model disk. The reconstruction of the model light curve seems to be fine but that of the model disk seems to be failed, smearing the brightness distribution along the ingress/egress arcs produced by the shadow of the secondary. We applied our method to the 2017 superoutburst of HT Cas. The artifacts smearing along the ingress/egress arcs of the secondary also exist. Unaccounted noise and the short phase coverage of the input light curves seem to affect the results, leading to small artificial bright spots in the reconstructed disk.