The nuclear source of the galactic wind in NGC 253

We present Brγ emission line kinematics of the nuclear region of NGC 253, recently known to host a strong galactic wind that limits the global star formation of the galaxy. We obtained high-resolution long-slit spectroscopic data with PHOENIX at Gemini South, positioning the slit on the nucleus infrared core (IRC), close to the nuclear disk major axis. The spatial resolution was 0.″35 (∼6 pc) and the slit length was 14″ (∼240 pc). The spectral resolution was ∼74,000, unprecedentedly high for galactic nuclei observations at ∼2.1 μm. The line profiles appear highly complex, with blue asymmetry up to 3.″5 away of the IRC, and red asymmetries further away to northeast. Several Gaussian components are necessary to fit the profile, nevertheless a narrow and a wide one predominate. The IRC presents kinematic widths above 700 km s-1 (FWZI), and broad component FWHM ∼ 400 km s-1, the highest detected in a nearby galaxy. At the IRC, the blueshifted broad component displays a 90 km s-1 bump in radial velocity distribution, a feature we previously detected in molecular gas kinematics. The narrow component velocity dispersion (∼32 km s-1) is within the expected for normal galaxies and luminous infrared galaxies (LIRGs). Intermediate components (FWHM ∼ 150 km s-1, redshifted to the northeast, blueshifted to the southwest) appear at some positions, as well as weaker blue (-215 km s-1) and red line wings (+300 km s-1). The IRC depicts a large broad-versus-narrow line flux ratio (F(B)/F(N) ∼ 1.35), and the broad component seems only comparable with those observed at very high star-forming rate galaxies. The results indicate that the IRC would be the main source of the galactic winds originated in the central region of NGC 253.Fil: Gunthardt, Guillermo Ivan. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Grupo de Medio Interest., Instument. y Galaxias; ArgentinaFil: Díaz, R. J.. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Grupo de Medio Interest., Instument. y Galaxias; Argentina. Gemini Observatory; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Agüero, Maria Paz. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Grupo de Medio Interest., Instument. y Galaxias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Gimeno, G.. Gemini Observatory; Estados UnidosFil: Dottori, H.. Universidade Federal do Rio Grande do Sul; BrasilFil: Camperi, Javier Antonio. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Grupo de Medio Interest., Instument. y Galaxias; Argentin

VVV DR1: The first data release of the Milky Way bulge and southern plane from the near-infrared ESO public survey VISTA variables in the Vía Láctea

Context. The ESO public survey VISTA variables in the Vía Láctea (VVV) started in 2010. VVV targets 562 sq. deg in the Galactic bulge and an adjacent plane region and is expected to run for about five years. Aims. We describe the progress of the survey observations in the first observing season, the observing strategy, and quality of the data obtained. Methods. The observations are carried out on the 4-m VISTA telescope in the ZYJHKs filters. In addition to the multi-band imaging the variability monitoring campaign in the Ks filter has started. Data reduction is carried out using the pipeline at the Cambridge Astronomical Survey Unit. The photometric and astrometric calibration is performed via the numerous 2MASS sources observed in each pointing. Results. The first data release contains the aperture photometry and astrometric catalogues for 348 individual pointings in the ZYJHKs filters taken in the 2010 observing season. The typical image quality is ~ 0.9-1.0. The stringent photometric and image quality requirements of the survey are satisfied in 100% of the JHKs images in the disk area and 90% of the JHKs images in the bulge area. The completeness in the Z and Y images is 84% in the disk, and 40% in the bulge. The first season catalogues contain 1.28 × 108 stellar sources in the bulge and 1.68 × 108 in the disk area detected in at least one of the photometric bands. The combined, multi-band catalogues contain more than 1.63 × 108 stellar sources. About 10% of these are double detections because of overlapping adjacent pointings. These overlapping multiple detections are used to characterise the quality of the data. The images in the JHKs bands extend typically ~4 mag deeper than 2MASS. The magnitude limit and photometric quality depend strongly on crowding in the inner Galactic regions. The astrometry for Ks = 15−18 mag has rms ~35−175 mas. Conclusions. The VVV Survey data products offer a unique dataset to map the stellar populations in the Galactic bulge and the adjacent plane and provide an exciting new tool for the study of the structure, content, and star-formation history of our Galaxy, as well as for investigations of the newly discovered star clusters, star-forming regions in the disk, high proper motion stars, asteroids, planetary nebulae, and other interesting objects.Peer reviewe