Searcharxiv⌕ Search

arXiv subjects

Georgi P. Petrov

Publications and source records attributed to Georgi P. Petrov.

2 recordsLinked to original sources

On the relationship between the ellipticity of Galactic globular clusters and their X-ray luminosity

We examine the dependence of the ellipticity of globular clusters in the Milky Way on their X-ray luminosity using two modern catalogs and combine them with optical and X-ray data from the literature. Kolmogorov-Smirnov tests applied across multiple subsets reveal statistically significant differences in the ellipticity distributions when both $L_{\rm X}$ and optical luminosity are considered. Two X-ray luminosity thresholds, $L_{\rm X}^*(M_{\rm{V}}=-7)=10^{33.05}$ erg/s and $L_{\rm X}^*(M_{\rm{V}}=-7)=10^{32.01}$ erg/s, yield the most reliable distinction. In contrast to earlier findings based solely on optical data, our results demonstrate that globular clusters with the highest X-ray luminosity tend to have higher ellipticity on average.

astro-ph.GA↗

A search for non-hidden broad-line region Seyfert 2 galaxies

According to the unified model of active galactic nuclei, Seyfert 2 galaxies are physically the same as Seyfert 1 objects and they possess a broad-line region (BLR), but it is hidden from the observer due to their orientation. In the past few years, various authors reported that not all Seyfert 2 galaxies harbor a BLR. We compiled a sample of 38 Seyfert 2 galaxies to find non-hidden broad-line region (non-HBLR) objects. Using the theory of Nicastro et al. which suggests the existence of a critical value of the Eddington ratio below which BLR can't be formed, we found 26 non-HBLR Seyfert 2 candidates. We found also that 5 of these 26 non-HBLR objects could be low-ionization nuclear emission-line regions (LINERs).

astro-ph.GA↗