相关论文: Verifying the Planetary Nebula Luminosity Function…

The measurement of precise galaxy distances by Cepheid observations out to the distance of the Virgo cluster is important for the determination of the Hubble constant ($H_0$). The Virgo cluster is thereby often used as an important stepping…

We present measurements of the galaxy luminosity and stellar mass function in a 3.71 deg$^2$ (0.3 Mpc$^2$) area in the core of the Virgo cluster, based on $ugriz$ data from the Next Generation Virgo Cluster Survey (NGVS). The galaxy sample…

We undertook a long term project, DIRECT, to obtain the direct distances to two important galaxies in the cosmological distance ladder -- M31 and M33 -- using detached eclipsing binaries (DEBs) and Cepheids. While rare and difficult to…

When astronomers study the dark matter halos of spiral galaxies, they normally assume that the disk mass-to-light ratio is *constant*. We describe a method of analyzing the kinematics of planetary nebulae (PNe) in nearby face-on spiral…

We revisit the filamentary structures of galaxies around the Virgo cluster, exploiting a larger dataset based on the HyperLeda database than previous studies. In particular, this includes a large number of low-luminosity galaxies, resulting…

We use the conditional luminosity function (CLF), which gives the number of galaxies with luminosities in the range [L, L+dL] that reside in a halo of mass M, to link the distribution of galaxies to that of dark matter haloes. We seek the…

We compare two methods for deriving distances to early-type galaxies: fundamental plane (FP) and surface brightness fluctuations (SBF) distances for 170 galaxies. A third set of distances is provided by predictions derived from the density…

We define here a standard candle to determine the distance of clusters of galaxies and to investigate their peculiar velocities by using the n^{th} rank galaxy (magnitude m$_n$). We address the question of the universality of the luminosity…

We present Surface Brightness Fluctuation distances of nine early-type dwarf galaxies and the S0 galaxy NGC 4150 in the Local Volume based on deep B- and R-band CCD images obtained with the 2.56 metre Nordic Optical Telescope. Typically,…

Classical and Type II Cepheids are used to reinvestigate specific properties of the Galaxy. A new Type II reddening-free Cepheid distance parameterization is formulated from LMC Cepheids (OGLE), with uncertainties typically no larger than…

We have applied the "Synthetic Field Method" on a sample of ~20 nearby galaxies in order to determine the opacity of their disks. We present preliminary results on the radial dependence of cold dust absorption for 3 examples. The spirals…

In this work, we discuss the determination of the distance to the Large Magellanic Cloud (LMC) using the Leavitt Law, utilizing the public catalog of Classical Cepheid Variable stars from the observational project OGLE-IV (The Optical…

In modern cosmology, determining the Hubble constant (H0) using distance ladder to percent level and comparing with the results from Planck satellite can shed light on the nature of the dark energy, the physics of neutrino, and the…

We constructed the composite Luminosity Function (LF) of cluster galaxies in the g,r and i bands from the photometry of a mixed (Abell and X-ray selected) sample of the cores of 65 clusters, ranging in redshift from 0.05 to 0.25. The…

Star clusters in 6 nearby spiral galaxies are examined using archive images from HST/WFPC2. The galaxies have previously been studied from the ground and some of them are known to possess rich populations of "young massive clusters" (YMCs).…

The diffuse extended outer regions of galaxies are hard to study because they are faint, with typical surface brightness of 1% of the dark night sky. We can tackle this problem by using resolved star tracers which remain visible at large…

We find that the bright part (M_B<-18.5 mag) of luminosity function of each Hubble type has the same shape in three poor clusters (Virgo, Fornax and Centaurus) and in two rich clusters (Coma and Cl0939+4713). The fact that these…

We first discuss why the uncomfortable fine-tuning of the parameters of the Lambda-CDM cosmological model provides continuing, strong motivation to investigate Hubble's Constant. Then we review evidence from the HST Key Project that there…

We investigated the optical properties of 7 clusters of galaxies observed in three colors over the range of absolute magnitudes -24 < M < -12. Our aim is to estimate the Luminosity Function and the total cluster luminosity of our sample in…

We have imaged an empty area of 34'x34' one and a half degree north of the Virgo cluster core to survey for intracluster planetary nebula candidates. We have implemented and tested a fully automatic procedure for the selection of emission…