24 citations · 114 across the 15 of their papers we have counts for
7 papers · 1 filter
Determination of the Hubble Constant Using Cepheids
Mohamed Abdel-Sabour, Mohamed Ebrahim Nouh, Issa Ali Issa +5
This paper introduces a statistical treatment to use Cepheid variable stars as distance indicators. The expansion rate of the Universe is also studied here through deriving the val…
Discovery of Dramatic Optical Variability in SDSS J1100+4421: A Peculiar Radio-Loud Narrow-Line Seyfert 1 Galaxy?
Masaomi Tanaka, Tomoki Morokuma, Ryosuke Itoh +55
We present our discovery of dramatic variability in SDSS J1100+4421 by the high-cadence transient survey Kiso Supernova Survey (KISS). The source brightened in the optical by at le…
Distortion of Infall Regions in Redshift Space-I
Mohamed H. Abdullah, Elizabeth A. Praton, Gamal B. Ali
We show that spherical infall models (SIMs) can better describe some galaxy clusters in redshift slice space than in traditional axially-convolved projection space. This is because…
Studying the Dynamical Properties of 20 Nearby Galaxy Clusters
Mohamed H. Abdullah, Gamal B. Ali, H. A. Ismail +1
Using SDSS-DR7, we construct a sample of 42382 galaxies with redshifts in the region of 20 galaxy clusters. Using two successive iterative methods, the adaptive kernel method and t…
Photometric Investigation of the Total-Eclipsing Contact Binary V12 in the Intermediate-age Open Cluster NGC 7789
S. -B. Qian, A. Essam, J. -J. Wang +3
NGC 7789 is an intermediate-age open cluster with an age that is similar to the mean age of contact binary stars. V12 is a bright UMa-type binary star with an orbital period of 0.3…
First photometric analyses and classification for the W UMa type binary systems GSC 2362-2866 and GSC 107-596
A. Essam, N. S. Awadalla, M. A. El-Sadek +1
The CCD observations for the W UMa type binary systems GSC 2362-2866 and GSC 107-596 have been analyzed using the Wilson-Devinney Code to determine their photometric orbital and ph…
Current and future capabilities of the 74-inch telescope of Kottamia astronomical observatory in Egypt
Y. A. Azzam, G. B. Ali, F. Elnagahy +4
In this paper, we are going to introduce the Kottamia Astronomical Observatory, KAO, to the astronomical community. The current status of the telescope together with the available…