http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
PHOTOMETRIC DECOMPOSITION OF MERGERS IN DISK GALAXIES
Mezcua, M.,Lobanov, A. P.,Mediavilla, E.,Karouzos, M. IOP Publishing 2014 The Astrophysical journal Vol.784 No.1
<P>Several observational studies and numerical simulations suggest that mergers must contribute to the evolution of galaxies; however, the role that they play is not yet fully understood. In this paper we study a sample of 52 double nucleus disk galaxies that are considered as candidates for a minor merger event. The luminosity of each of the nuclei and their relative separation are derived from a multi-component photometric fit of the galaxies in the Sloan Digital Sky Survey optical images. We find that the nuclei in most of the sources have projected separations <= 4 kpc. The ratio of nuclear luminosities indicates that most of the systems are likely in the coalescence stage of a major merger. This is supported by the existence of a single galaxy disk in 65% of the systems studied and the finding of a correlation between nuclear luminosity and host luminosity for the single-disk systems: those sources fitted with as single disk are in a more evolved stage of the merger and present an enhancement of the nuclear luminosity compared to the double-disk systems, as expected from simulations of galaxy mergers. Finally, we identify a sample of 19 double nucleus disk galaxies in which the two nuclei are physically separated by <= 1 kpc and constitute thus a sample of sub-kpc binary active galactic nucleus candidates.</P>
INTRA-NIGHT OPTICAL VARIABILITY OF ACTIVE GALACTIC NUCLEI IN THE COSMOS FIELD WITH THE KMTNET
김준호,Marios Karouzos,임명신,최상수,김도형,전현성,이준협,Mar Mezcua 한국천문학회 2018 Journal of The Korean Astronomical Society Vol.51 No.4
Active Galactic Nucleus (AGN) variability can be used to study the physics of the region in the vicinity of the central black hole. In this paper, we investigated intra-night optical variability of AGN in the COSMOS field in order to understand the AGN instability at the smallest scale. Observations were performed using the KMTNet on three separate nights for 2.5 to 5 hours at a cadence of 20 to 30 min. We find that the observation enables the detection of short-term variability as small as $\sim 0.02$ and 0.1 mag for $R \sim 18$ and 20 mag sources, respectively. Using four selection methods (X-rays, mid-infrared, radio, and matching with SDSS quasars), 394 AGN are detected in the 4 deg$^2$ field of view. After differential photometry and $\chi^2-$test, we classify intra-night variable AGN. The fraction of variable AGN (0--8\%) is statistically consistent with a null result. Eight out of 394 AGN are found to be intra-night variable in two filters or two nights with a variability level of 0.1 mag, suggesting that they are strong candidates for intra-night variable AGN. Still they represent a small population (2\%). There is no sub-category of AGN that shows a statistically significant intra-night variability.