相关论文: The luminosity function of white dwarfs and M dwar…

We perform a deep survey of planetary nebulae (PNe) in the spiral galaxy NGC 300 to construct its planetary nebula luminosity function (PNLF). We aim to derive the distance using the PNLF and to probe the characteristics of the most…

We analyze 166 spheroid subdwarfs $(6.5<M_V<14.5)$ found in 53 fields observed with the Wide Field Camera on the {\it Hubble Space Telescope}. The fields cover 221 square arcmin over a wide range of directions. The spheroid luminosity…

Redshift surveys like the Sloan Digital Sky Survey (SDSS) have given a very precise measurement of the galaxy luminosity function down to about M_R = -17 (~ M_B = -16). Fainter absolute magnitudes cannot be probed because of the flux limit…

We present CCD surface photometry of 16 nearby dwarf galaxies, many of which were only recently discovered. Our sample comprises both isolated galaxies and galaxies that are members of nearby galaxy groups. The observations were obtained in…

We have used public data from the Next Generation Virgo Survey (NGVS) to investigate the dwarf galaxy population of the Virgo cluster beyond what has previously been discovered. We initially mask and smooth the data, and then use the object…

M dwarfs are prime targets in the hunt for habitable worlds around other stars. This is due to their abundance as well as their small radii and low masses and temperatures, which facilitate the detection of temperate, rocky planets in orbit…

Deep measurements are presented of four rich clusters of galaxies: Abell 1367 (z=0.022), Abell 2199 (z=0.030), Abell 1795 (z=0.063), and Abell 1146 (z=0.141). All clusters have an excess of galaxies at faint magnitudes above blank sky…

Deep photometric observations in three colours of the cluster A 496 show that the luminosity function is bimodal with a deep gap at g about 19.0. That is there is a net separation between E/SO galaxies that are nicely fitted by a gaussian…

We have conducted a search of a 9 deg$^{2}$ region of the CFHTLS around the Milky Way analog M101 (D$\sim$7 Mpc), in order to look for previously unknown low surface brightness galaxies. This search has uncovered 38 new low surface…

Context. M dwarfs are an ideal laboratory for hunting Earth-like planets, and the study of chromospheric activity is an important part of this task. On the one hand, its short-term activity show high levels of magnetic activity that can…

We present maps of 1.5 square degrees of the Serpens dark cloud at 24, 70, and 160\micron observed with the Spitzer Space Telescope MIPS Camera. More than 2400 compact sources have been extracted at 24um, nearly 100 at 70um, and 4 at 160um.…

We measure the luminosity function (LF) of the Milky Way's stellar halo, using a magnitude complete, distance limited sample of stars from $Gaia$ DR3. Stars with high transverse velocities are selected, to isolate a high purity sample of…

We carried out the largest ($>3.5\times10^5$ Mpc$^3$, 26 deg$^2$) H$\alpha$ narrow band survey to date at $z\sim0.2$ in the SA22, W2 and XMMLSS extragalactic fields. Our survey covers a large enough volume to overcome cosmic variance and to…

We have performed a search for halo white dwarfs as high proper motion objects in a second epoch WFPC2 image of the Groth-Westphal strip. We identify 24 high proper motion objects with mu > 0.014 ''/yr. Five of these high proper motion…

The recent discovery of microlensing of stars in the Large Magellanic Cloud has excited much interest in the nature of the lensing population. Detailed analyses indicate that the mass of these objects ranges from 0.3-0.8 solar masses,…

We describe the use of partially overlapping galaxies to provide direct measurements of the effective absorption in galaxy disks, independent of assumptions about internal disk structure. The non-overlapping parts of the galaxies and…

Dwarf satellite galaxies are a key probe of dark matter and of galaxy formation on small scales and of the dark matter halo masses of their central galaxies. They have very low surface brightness, which makes it difficult to identify and…

We use a sample of rest-frame UV selected and spectroscopically observed galaxies at redshifts 1.9<z<3.4, combined with ground-based spectroscopic H-alpha and Spitzer MIPS 24 micron data, to derive the most robust measurements of the…

We perform a spectroscopic survey of the foreground population in Orion A with MMT/Hectospec. We use these data, along with archival spectroscopic data and photometric data, to derive spectral types, extinction values, and masses for 691…

We present the UV composite luminosity function for galaxies in the Virgo, Coma and Abell 1367 clusters. The luminosity function (LF) is well fitted by a Schechter function with M*(UV} - 5*log h(75) = -20.75 +/- 0.40 and alpha = -1.50 +/-…