Aims: We derive the vertical velocities of disk stars in the range of Galactocentric radii of R = 5 - 16 kpc within 2 kpc in height from the Galactic plane. This kinematic information is connected to dynamical aspects in the formation and evolution of the Milky Way, such as the passage of satellites and vertical resonance and determines whether the

We present the identification and characterization of the optical counterpart to 2XMM J011942.7+032421, one of the most luminous and distant ultra-luminous X-ray sources (ULXs). The counterpart is located near a star-forming region in a spiral arm of the galaxy NGC 470 with u, g, and r magnitudes of 21.53, 21.69, and 21.71 mag, respectively. The

Context. Most of the contribution to dust emission in clusters of galaxies comes from late-type galaxies. However, several ejection processes of material from these galaxies could introduce dust in the intracluster media. Even a relatively low abundance of this dust could act as an efficient cooling agent and have a relevant role in the evolution

Context. Some observations indicate that the Milky Way has two inner components, a bulge and a long bar, which present a misalignment of Δα ≃ 20° that is against the predictions of some theoretical models that are based on numerical simulations. Aims: We wish to determine whether this misalignment between the bar and the bulge can be observed in

We study the dynamical interactions of mass systems in equilibrium under their own gravity that mutually exert and experience gravitational forces. The method we employ is to model the dynamical evolution of two isolated bars, hosted within the same galactic system, under their mutual gravitational interaction. In this study, we present an

Aims: We explore the outer Galactic disc up to a Galactocentric distance of ≈30 kpc to derive its parameters and measure the magnitude of its flare. Methods: We obtained the 3D density of stars of type F8V-G5V with a colour selection from extinction-corrected photometric data of the Sloan Digital Sky Survey - Sloan Extension for Galactic

We have identified ionized outflows in the narrow-line region of all but one Sloan Digital Sky Survey type 2 quasars (QSO2) at z≲0.1 (20/21, detection rate 95 per cent), implying that this is a ubiquitous phenomenon in this object class also at the lowest z. The outflowing gas has high densities (ne≳1000 cm-3) and covers a region the size of a few

Aims: We derive the stellar rotation curve of the Galaxy in the range of Galactocentric radii of R = 4-16 kpc at different vertical heights from the Galactic plane of z between -2 and +2 kpc. With this we reach high Galactocentric distances in which the kinematics is poorly known due mainly to uncertainties in the distances to the sources. Methods

While the shape of the extinction curve in the infrared is considered to be set and the extinction ratios between infrared bands are usually taken to be approximately constant, a number of recent studies point to either a spatially variable behavior of the exponent of the power law or a different extinction law altogether. In this paper, we propose

Context. There is still some debate about the presence and the morphological properties of the long bar in the inner Galaxy. Aims: We investigate the morphological properties of the long Galactic bar using the VVV survey extending star counts at least 3 mag deeper than 2MASS. Our study covers the relatively unexplored negative longitudes of the

Long-duration gamma-ray bursts (GRBs) at z < 1 are found in most cases to be accompanied by bright, broad-lined Type Ic supernovae (SNe Ic-BL). The highest-energy GRBs are mostly located at higher redshifts, where the associated SNe are hard to detect observationally. Here, we present early and late observations of the optical counterpart of the

Galactic black hole transients show many interesting phenomena during outburst decays. We present simultaneous X-ray (RXTE, Swift, and INTEGRAL), and optical/near-infrared (O/NIR) observations (SMARTS) of the X-ray transient XTE J1752–223 during its outburst decay in 2010. The multiwavelength observations over 150 days in 2010 cover the transition

We calibrated the absolute magnitudes M V , M J , M_{Ks} and M g of red clump stars in terms of colours. M V and M g are strongly dependent on colour, while the dependence of M J and M_{Ks} on colour is rather weak. The calibration of the absolute magnitudes M V and M_{Ks} is tested on 101 RC stars in the field SA 141. The Galactic model parameters

Context. The nature of ultra-luminous X-ray (ULX) sources is still a matter of debate. Studies of their counterparts in other spectral ranges will help to clarify the nature of those sources. Aims: Our goal was to identify and characterize the optical counterparts of five sources catalogued as ULXs. Methods: We obtained optical imaging and

Context. Although many studies have been performed so far, there are still dozens of low-mass stars and brown dwarfs in the young σ Orionis open cluster without detailed spectroscopic characterisation. Aims: We look for unknown strong accretors and disc hosts that were undetected in previous surveys. Methods: We collected low-resolution

Context. The VISTA Variable Survey (VVV) is able to map the Galaxy at l ≤ 0° with an unpaired depth (at least 3 mag deeper than 2MASS), opening new possibilities for studying the inner structure of the Milky Way. Aims: In this paper we concentrate on the exploitation of these data to better understand the spatial disposition and distribution of the

The observation of blank fields, defined as regions of the sky that are devoid of stars down to a given threshold magnitude, constitutes one of the most relevant calibration procedures required for the proper reduction of astronomical data obtained following typical observing strategies. In this work, we have used Delaunay triangulation to search

Aims: We present optical photometry and spectroscopy of the afterglow and host galaxy of gamma-ray burst GRB 040924. This GRB had a rather short duration of T90 ~2.4 s, and a well sampled optical afterglow light curve. We aim to use this dataset to find further evidence that this burst is consistent with a massive star core-collapse progenitor

From the equivalent widths of the main features of the K band spectra (the NaI, CaI and CO bandheads) we have derived the metallicities of the sources by means of the empirical scale obtained by Ramirez et al. (2000AJ....120..833R) and Frogel et al. (2001AJ....122.1896F) for luminous red giants. (2 data files).

We present colour transformations for the conversion of the 2MASS photometric system to the Johnson-Cousins UBVRI system and further into the SDSS ugriz system. We have taken SDSS gri magnitudes of stars measured with the 2.5-m telescope from SDSS Data Release 5 (DR5), and BVRI and JHKs magnitudes from Stetson's catalogue (available at http://www2