This work aims to study the evolution of galaxies, located in the dense environment of the NGC 4095 compact group, which have recession velocities 6,000 < v (km s-1) < 8,000. Imaging observations for BV Rc broad-band, and [S ii] and red-continuum narrow-band were carried out with the 2.4 m Thai National Telescope (TNT) at Doi Inthanon, Chiang Mai, Thailand. The sample contains 13 galaxies, consisting of 8 spirals, 4 ellipticals and 1 irregular morphological type. Late type galaxies tend to be bluer than early type galaxies. The results show that most of the late type galaxies have ongoing star formation activity, which could be triggered by galaxy-galaxy or tidal interactions, and that young massive stars in these galaxies cause their colors to be bluer than the early type galaxies.

We presents a study of interactions between galaxies in the low-redshift group known as the NGC 4065 group. Imaging data were taken using the 2.4 meter telescope at the Thai National Observatory (TNO) for B, V and Rc broadband filters and [S ii] and Red-continuum narrowband filters. There are 21 galaxies in our sample. The results show that most early type galaxies (ETGs) with equivalent width EW(Hα) < 10 Å are gas-deficient galaxies, while late type galaxies (LTGs) show more EW(Hα) and are bluer than the ETGs. This means that star formation activity in the LTGs could be triggered by tidal interactions between galaxy members due to dense environmental effects in the compact group.

Recently, cosmic voids have been recognized as a powerful cosmological probe. A number of studies have focused on the effects of the gravitational lensing by voids on the temperature (and in some cases polarization) anisotropy of the Cosmic Microwave Background (CMB) background at relatively large to medium scales, l ~ 1000. Many of these studies attempt to explain the unusually large cold spot in CMB temperature maps and dynamical evidence of dark energy via detections of late-time integrated Sachs Wolfe (ISW) effect. Here, the effects of lensing by voids on the CMB temperature anisotropy at small scales, up to l = 3000, will be investigated. This work is carried out in the light of the benefits of adding large catalogues of cosmic voids, to be identified by future large galaxy surveys such as EUCLID and LSST, to the analysis of CMB data such as those from Planck mission. Our numerical simulation utilizes two methods, namely, the small-de ectionangle approximation and full ray-tracing analysis. Using the fitted void density profiles and radius (RV ) distribution available in the literature from N-body simulations, we simulated the secondary temperature anisotropy (lensing) of CMB photons induced by voids along a line of sight from redshift 0 to 2. Each line of sight contains approximately 1000 voids of effective radius RV;eff = 35 h-1Mpc with randomly distributed radial and projected positions. Both methods are used to generate temperature maps. The two methods will be compared for their accuracy and effciency in the implementation of theoretical modeling.