Related papers: A and F stars as probes of outer Galactic disc kin…

Stars are not perfectly spherically symmetric. They are deformed by rotation and magnetic fields. Until now, the study of stellar shapes has only been possible with optical interferometry for a few of the fastest-rotating nearby stars. We…

We present the results of a large-scale proper motion study of the central ~36'x16' of the Milky Way, based on our high angular resolution GALACTICNUCLEUS survey (epoch 2015) combined with the HST Paschen-alpha survey (epoch 2008). Our…

In recent years, it has been demonstrated that massive stars see their infant circumstellar medium shaped into a large, irradiated, gravitationally unstable accretion disc during their early formation phase. Such discs constitute the gas…

The rotation curve of the Galaxy is generally thought to be flat. However, using radial velocities from interstellar molecular clouds, which is common in rotation curve determination, seems to be incorrect and may lead to incorrectly…

We report a detailed investigation of the bulk motions of the nearby Galactic stellar disk, based on three samples selected from the LSS-GAC DR2: a global sample containing 0.57 million FGK dwarfs out to $\sim$ 2 kpc, a local subset of the…

In this letter we study the observed distributions of rotational velocity in a sample of more than 16,000 nearby F and G dwarf stars, magnitude complete and presenting high precision $Vsin i$ measurements. We show that the velocity…

The density wave theory predicted some physical offsets among different tracers of star formation. To test this prediction, here we compiled data on 40 galaxies searched observationally for a physical offset between spiral arm tracers, and…

We present $\gtrsim 15,000$ metal-rich (${\rm [Fe/H]}>-0.2$dex) A and F stars whose surface abundances deviate strongly from Solar abundance ratios and cannot plausibly reflect their birth material composition. These stars are identified by…

Projected rotational velocities (vsini) are presented for a sample of 350 early B-type main sequence stars in the nearby Galactic disk. The stars are located within ~1.5 kpc from the Sun, and the great majority within 700 pc. The analysis…

We use the Stripe 82 proper motion catalogue of Bramich et al. (2008) to study the kinematics of Galactic disk stars in the solar neighborhood. We select samples of dwarf stars with reliable spectra and proper motions. They have cylindrical…

Context: Rotation plays a key role in the life cycles of stars with masses above 8 Msun. Hence, accurate knowledge of the rotation rates of such massive stars is critical for understanding their properties and for constraining models of…

Over a two year period (1995-1997), we have conducted a diffraction-limited imaging study at 2.2 microns of the inner 6"x6" of the Galaxy's central stellar cluster using the Keck 10-m telescope. The K band images obtained reveal a large…

Our study aims to investigate the outer disc structure of the Milky Way galaxy using the red clump (RC) stars. We analysed the distribution of the largest sample of RC stars to date, homogeneously covering the entire Galactic plane in the…

We confirm, quantify, and provide a table of the coherent velocity substructure of the Milky Way disk within 2 kpc of the Sun towards the Galactic anticenter, with 0.2 kpc resolution. We use the radial velocities of ~340,000 F-type stars…

The outer parts of the Milky Way's disc are significantly out of equilibrium. Using only distances and proper motions of stars from Gaia's Early Data Release 3, in the range |b|<10{\deg}, 130{\deg}<l<230{\deg}, we show that for stars in the…

Aims: Our aim is to provide an observational view of the old Disc structure of the Milky Way galaxy using the distribution of red clump stars. The spiral arms, warp structure, and other asymmetries present in the Disc are re-visited using a…

We present kinematic measurements of the thick and thin disks in two edge-on galaxies. We have derived stellar rotation curves at and above the galaxies' midplanes using Ca II triplet features measured with the GMOS spectrograph on Gemini…

To explore the properties of extreme outer stellar disks, we obtained ultra-deep V and GALEX UV images of 4 dwarf irregular galaxies and one Blue Compact Dwarf galaxy and ultra-deep B images of 3 of these. Our V-band surface photometry…

We analyse the global structure of the old stellar discs in 34 edge-on spiral galaxies. The radial and vertical exponential scale parameters of the discs are obtained by applying an improved two-dimensional decomposition technique to our…

In the search of a sample of metal-poor bright giants using Str{\"o}mgren photometry, we serendipitously found a sample of 26 young (ages younger than 1 Gyr) metal-rich giants, some of which have high rotational velocities.We determined the…