148 datasets found

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 radial velocity (RV) is a basic physical quantity that can be determined through the Doppler shift of the spectrum of a star. The precision of the RV measurement depends on...

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 report the discovery of a young (only 30-40Myr) snake-like structure (dubbed a stellar snake) in the solar neighborhood from Gaia DR2. The average distance of this structure...

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...

A sample of 102 local (0.02=<z=<0.1) Seyfert galaxies with black hole masses M_BH_>10^7^M_{sun} was selected from the Sloan Digital Sky Survey (SDSS) and observed using...

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)...

We present a sample of 407 z~3 Lyman break galaxies (LBGs) to a limiting isophotal u-band magnitude of 27.6mag in the Hubble Ultra Deep Field. The LBGs are selected using a...

We present the first results from a high sampling rate, multimonth reverberation mapping campaign undertaken primarily at MDM Observatory with supporting observations from...

We selected 40 candidate Ly{alpha}-emitting galaxies (LAEs) at z~3.1 with observed-frame equivalent widths greater than 150{AA} and inferred emission-line fluxes above...

We find a significant correlation between the magnetic and rotational moments for a sample of 112 lower main-sequence stars. The rotational moment is calculated from...

We assemble a large sample of 12784 high-velocity stars with total velocity VGSR>~300km/s, selected from RAVE DR5, SDSS DR12, LAMOST DR8, APOGEE DR16, GALAH DR2, and Gaia...