996 datasets found

We discuss 76 large amplitude transients ({Delta}m>1.5) occurring in the nuclei of galaxies, nearly all with no previously known active galactic nucleus (AGN). They have been...

1 per cent of redshift z~0.1 active galactic nuclei (AGNs) show velocity splitting of a few hundred km/s in the narrow emission lines in spatially integrated spectra. Such line...

In this paper, we extend our work of IV {lambda}{lambda}1548,1551 narrow absorption lines (NALs) with z_abs_<<z_em_ on quasar spectra of the Baryon Oscillation...

T CrB is a symbiotic recurrent nova known to exhibit active phases, characterized by apparent increases in the hot component temperature and the appearance of flickering, i.e....

We have investigated the diffuse interstellar band (DIB) at 661.3nm seen in the spectra of Cepheid stars. After removal of the blending lines of ionized yttrium and neutral...

I have reinterpreted Rucinski's line profiles (broadening functions) for the hot A-type W Ursae Majoris binary AW UMa in terms of various contact models, finding that the...

We present a detailed analysis of the chemistry and kinematics of red giants in the dwarf irregular galaxy NGC 6822. Spectroscopy at ~8500{AA} was acquired for 72 red giant...

Measurements are presented and analysed of the strength of the CaII triplet lines in red giants in Galactic globular and open clusters, and in a sample of red giants in the LMC...

The dust content of damped Lyman {alpha} systems (DLAs) is an important observable for understanding their origin and the neutral gas reservoirs of galaxies. While the average...

Diffuse interstellar bands (DIBs) trace warm neutral and weakly ionized diffuse interstellar medium (ISM). Here we present a dedicated, high signal-to-noise spectroscopic survey...

The variability of broad absorption lines (BALs) is investigated for a sample of 188 BAL quasars (QSOs) (z>1.7) with at least two epoch observations from the Sloan Digital...

We have observed high-dispersion echelle spectra of main-sequence stars in five nearby young associations - Argus, Carina-Near, Hercules-Lyra, Orion and Subgroup B4 - and...

A new method of image subtraction is applied to images from a J, K, and narrow-band imaging survey of 300 deg2 of the plane of the Galaxy, searching for new Wolf-Rayet (WR)...

We report on the determination of the lithium abundance [A(Li)] of 52 solar-like stars. For 41 objects the A(Li) here presented corresponds to the first measurement. We have...

We present photometry in U, B, V, R and I continuum bands and in H{alpha} and H{beta} emission lines for a sample of 336 circumnuclear star-forming regions located in early-type...

We introduce Coronal-Line Forest active galactic nuclei (CLiF AGN), AGN which have a rich spectrum of forbidden high-ionization lines (FHILs, e.g. [FeVII], [FeX] and [NeV]), as...

We present 237 new spectroscopically confirmed pre-main-sequence K- and M-type stars in the young Upper Scorpius subgroup of the Sco-Cen association, the nearest region of...

Detailed chemical abundances are presented for seven M31 outer halo globular clusters (with projected distances from M31 greater than 30 kpc), as derived from high-resolution...

We have analysed a sample of 18 RR Lyrae stars (17 fundamental-mode - RRab - and one first overtone - RRc) and three Population II Cepheids (two BL Her stars and one W Vir...

We present detailed chemical compositions of 10 red giant star members of the Galactic (open) cluster NGC 752, derived from high-resolution (R~60000), high signal-to-noise...