151 datasets found

We present time-series optical spectroscopy of two stellar flares with complex multi-peaked light curves: a 2.1_-.3_^+.4^x10^34^erg flare from an M8 ultra-cool dwarf, and a...

This catalogue includes the DDO photometry and the radial velocities observed for the study of the kinematics and abundance gradients of G and K stars in the Galactic poles...

UBV observations of UV Cas during 1996-1999 show mostly irregular light variations.

Variability of the continuum, H{beta}, H{gamma} and HeII(4686{AA}) fluxes of the Seyfert I galaxy Mrk 509 is studied using spectra obtained on the 2.6-m telescope of the Crimean...

We use the most homogeneous Geneva seven-colour photometric system to derive new metallicity calibrations for early A- to K-type stars that cover both, dwarf stars and giants....

Here we present the spectropolarimetric observations of the radio-loud active galaxy 3C 390.3 in the period 2009-2014 (24 epochs). The galaxy has been observed with the 6-m...

We present new calculations of unified line profiles for hydrogen perturbed by collisions with protons. We report on new calculations of the potential energies and dipole...

This investigation is mainly related to hydrogen lines in the spectrum of NGC 7469 from the 1972-1990 data obtained using an image tube on the 2.6-m telescope of the Crimean...

The central region of the Virgo cluster of galaxies contains thousands of globular clusters (GCs), an order of magnitude more than the numbers found in the Local Group. Relics...

Results of a ground-based optical monitoring campaign on 3C 390.3 in 1994-1995 are presented. The broadband fluxes (B, V, R, and I), the spectrophotometric optical continuum...

The H{gamma} and H{delta} absorption features are measured in a sample of 455 (out of an original 460) Lick IDS stars with pseudo-equivalent width indices. For each Balmer...

Changing-look active galactic nucleus NGC4151, which has attracted a lot of attention, is undergoing the second dramatic outburst stage in its evolutionary history. To...

State-of-the-art radial velocity (RV) exoplanet searches are limited by the effects of stellar magnetic activity. Magnetically active spots, plage, and network regions each have...

We present a catalog of 531 white dwarf candidates that have large apparent transverse motions relative to the Sun (v_T_>200km/s), thus making them likely members of the...

In this paper, we use a machine-learning method, random forest (RF), to identify reliable members of the old (4Gyr) open cluster M67 based on the high-precision astrometry and...

We selected 4593 hot subdwarf candidates from the Gaia DR2 Hertzsprung-Russell (HR) diagram. By combining the sample with Large Sky Area Multi-Object Fibre Spectroscopic...

KA1858+4850 is a narrow-line Seyfert 1 galaxy at redshift 0.078 and is among the brightest active galaxies monitored by the Kepler mission. We have carried out a reverberation...

The ionizing fluxes from quasars and other active galactic nuclei (AGNs) are critical for interpreting their emission-line spectra and for photoionizing and heating the...

A small fraction of quasars have long been known to show bulk velocity offsets (of a few hundred to thousands of km/s) in the broad Balmer lines with respect to the systemic...

We use broadband photometry extending from the rest-frame UV to the near-IR to fit the individual spectral energy distributions of 63 bright (L(Ly{alpha})>10^43^ erg/s)...