The results on the deep low dispersion (1250 Å/mm at Hɤ, 30° < I < 165°, 195° < I < 210°, |b| < 5°; 7000Å/mm at A band, 50° < I < 115°, b=0°, b=±3.5°) spectral surveys of the MILKY WAY are presented. More than 2250 carbon stars were identified among them 1440 new ones. The C/M5+ ratio increases from 0.02 to 0.3 when longitude varies from 30° to 210°. On the basis of A GENERAL CATALOG OF GALACTIC COOL CARBON STARS the surface distribution of carbon stars has been studied.

The imaging spectroscopic observations of the Magellanic irregular galaxy NGC 4449 were made to show the detailed kinematic structure of the galaxy. Many filamentary structures and Several bubble-like structures are recognized in a 3D data cube of H$\alpha$ 수식 이미지 emission line. Velocity field shows the kpc-scale mosaic structure and counter- rotation of ionized gas.

There is an excess gamma flux from the general direction of the Galactic North Pole compared with that from the south when allowance is made for the contribution from CR interactions with the HI gas (Osborne et al., 1994). The extent to which it is in accord with the predictions of Wdowczyk and Wolfendale (1990 a,b) for gamma rays secondary to very high energy CR escaping from the VIRGO cluster is examined and it is claimed that the observations may well be of the order of those expected.

We present VR CCD photometry and long-slit spectroscopy of a late type spiral galaxy NGC 7678. The grey scale images and isophotal maps illustrate the presence of a weak bar from which spiral arms emerge. There are many HII regions along the spiral arms, but bright giant HII regions are more concentrated in the massive southern arm. The bright compact nucleus of NGC 7678 is bluer than bulge and bar. The spectral features of the nucleus and HII regoins are very similar but the nuclear spectra shows higher [NII]⋋6583/Hα than those of the HII regions. The nucleus of NGC 7678 seems to be intermediate type between HII region nulcei and LINERs by the ratio of [NII]⋋6583/Hα, but it is more likely to be HII region-like nucleus if we consider the [NII]⋋6716,6731/Hα together. The star formation rate is estimated to be about 0.2 M⊙ yr-1 based on the Hα flux.

To examine the effect of neighboring galaxies on the gravitational lensing statistics, we performed numerical simulations of lensing by many galaxies. The models consist of a galaxy in the rich cluster like Coma, or a galaxy surrounded by field galaxies in Ω0 = 1 universe with Ωgal = 0.1, Ωgal = 0.3 or Ωgal=1.0, Ωgal is the total mass in galaxies. Field galaxies either have the same mass or follow Schechter luminosity function and luminosity-velocity relation. Each lensing galaxy is assumed to be singular isothermal sphere (SIS) with finite cutoff radius. In most simulations, the lensing is mainly due to the single galaxy. But in Ωgal = 0.3 universe, one out of five simulations have 'collective lensing' event in which more than two galaxies collectively produce multiple images. These cases cannot be incorporated into the simple 'standard' lensing statistics calculations. In cases where 'collective lensing' does not occur, distribution of image separation changes from delta function to bimodal distribution due to shear induced by the surrounding galaxies. The amount of spread in the distribution is from a few % up to ~50% of the mean image separation in case when the galaxy is in the Coma-like cluster or when the galaxy is in the field with Ωgal = 0.1 or Ωgal=0.3. The mean of the image separation changes less than 5% compared with a single lens case. Cross section for multiple image lensing turns out to be relatively insensitive to the presence of the neighboring galaxies, changing less than 5% for Coma-like cluster and Ωgal=0.1, 0.3 universe cases. So we conclude that Coma-like cluster or field galaxies whose total mass density Ωgal < 0.3 do not significantly affect the probability of multiple image lensing if we exclude the 'collective lensing' cases. However, the distribution of the image separations can be significantly affected especially if the 'collective lensing' cases are included. Therefore, the effects of surrounding galaxies may not be negligible when statistics of lensing is used to deduce the cosmological informations.

The previous study of chemical evolution of the Galaxy is extended to the radial properties of the Galactic disk. The present model includes radial dependency of the time-dependent bimodal IMF, radial flow of material in the disk, and the change of type I supernova explosion rate with radial distance from the disk center as model parameters and observed gas and stellar density distributions and metallicity abundance gradient as observational constraints. The results of two models in this study explain the observed gas and stellar density distributions well, with the slope of the gas density gradient in the region of 4.5 kpc<r<12kpc as -0.136dex/kpc in model Y1 and -0.123dex/kpc in model Y2, respectively, which fit well the observed gradient of -0.l1dex/kpc. The abundance gradient reproduced in model Y1 is getting flatter with decreasing radius, while that in model Y2 is getting steeper, which fits better the observed abundance gradient. This result shows the necessity of exponentially increasing type I supernova explosion rate with decreasing radius in order to explain the observed abundance gradient in the disk. The fitness of observed density distribution and star formation rate distribution justifies the reliability of time-dependent bimodal IMF as a compound quantitative chemical evolution model of the Galaxy. The temporal variations of metallicity gradients for carbon, nitrogen and oxygen are also shown.

Deep V I CCD photometry of the Pegasus dwarf irregular galaxy shows that the tip of the red giant branch (RGB) is located at I = 21.15±0.10 mag and (V - I) = 1.58±0.03. Using the I magnitude of the tip of the RGB (TRGB), the distance modulus of the Pegasus galaxy is estimated to be (m-M)o=25.13±0.11 mag (corresponding to a distance of d = 1060±50 kpc). This result is in a good agreement with the recent distance estimate based on the TRGB method by Aparicio [1994, ApJ, 437, L27], (m-M)o = 24.9 (d = 950 kpc). However, our distance estimate is much smaller than that based on the Cepheid variable candidates by Hoessel et al.[1990, AJ, 100, 1151], (m-M)o=26.22±0.20 (d = 1750±160 kpc) mag. The color-magnitude diagram illustrates that the Cepheid candidates used by Hoessel et al.are not located in the Cepheid instability strip, but in the upper part of the giant branch. This result shows that the Cepheid candidates studied by Hoessel et al.are probably not Cepheids, but other types of variable stars. Taking the average of our distance estimate and Aparicio's, the distance to the Pegasus galaxy is d= 1000±80 kpc. Considering the distance and velocity of the Pegasus galaxy with respect to the center of the Local Group, we conclude that the Pegasus galaxy is probably a member of the Local Group.

Recent redshift surveys suggest that most galaxies may be distributed on the surfaces of bubbles surrounding large voids. To investigate the quantitative consistency of this qualitative picture of large-scale structure, we study analytically the clustering properties of galaxies in a universe filled with spherical shells. In this paper, we report the results of the calculations for the spatial and angular two-point correlation functions of galaxies. With ∼20 ∼20 of galaxies in clusters and a power law distribution of shell sizes, nsh(R)∼R−α nsh(R)∼R−α , α≃4 α≃4 , the observed slope and amplitude of the spatial two-point correlation function ξgg(r) ξgg(r) can be reproduced. (It has been shown that the same model parameters reproduce the enhanced cluster two-point correlation function, ξcc(r) ξcc(r) ). The corresponding angular two-point correlation function w(θ) w(θ) is calculated using the relativistic form of Limber's equation and the Schecter-type luminosity function. The calculated w(θ θ ) agrees with the observed one quite well on small separations (θ≲2deg θ≲2deg ).