We present three color, BVI maps of the Small Magellanic Cloud. The maps contain precise photometric and astrometric data for about 2.2million stars from the central regions of the SMC bar covering ~2.4 square degrees on the sky. Mean brightness of stars is derived from observations collected in the course of the OGLE-II microlensing search from about 130, 30 and 15 measurements in the I, V and B-bands, respectively. Accuracy of the zero points of photometry is about 0.01mag, and astrometry 0.15arcsec (with possible systematic error up to 0.7arcsec). Color magnitude diagrams of observed fields are also presented. The maps of the SMC are the first from the series of similar maps covering other OGLE fields: LMC, Galactic bulge and Galactic disk. The data are very well suited for many projects, particularly for the SMC which has been neglected photometrically for years.
We have undertaken a comprehensive search for 5-cm excited OH maser emission from evolved stars representative of various stages of late stellar evolution. Observed sources were selected from known 18-cm OH sources. This survey was conducted with the 100-m Effelsberg telescope, at 6.0GHz in Sep 2000, to achieve high signal to noise ratio observations and a sensitivity limit of about 0.05 to 0.1Jy. A total of 65 stellar sources were searched for both main line and satellite line emission. We confirm the previous detection of 5 cm OH in Vy 2-2, do not confirm emission from NML-Cyg and do not report any other new detection within the above sensitivity limit. The number of observed sources is 67.
We present the final results from the Arecibo Observatory OH megamaser survey. We discuss in detail the properties of the remaining 18 OH megamasers detected in the survey, including three redetections. We place upper limits on the OH emission from 85 nondetections and examine the properties of 25 ambiguous cases for which the presence or absence of OH emission could not be determined. The complete survey has discovered 50 new OH megamasers (OHMs) in (ultra)luminous infrared galaxies ([U]LIRGs), which doubles the sample of known OHMs and increases the sample at z>0.1 sevenfold.
We have carried out a wide-field imaging survey for [OII] {lambda}3727 emitting galaxies at z~1.2 in the HST COSMOS 2 square degree field using the Suprime-Cam on the Subaru Telescope. The survey covers a sky area of 6700arcmin^2^ in the COSMOS field, and a redshift range between 1.17 and 1.20 ({Delta}z=0.03), corresponding to a survey volume of 5.56x10^5^Mpc^3^. We obtain a sample of 3176 [OII] emitting galaxies with observed emission-line equivalent widths greater than 26{AA}. Since our survey tends to sample brighter [OII] emitting galaxies, we also analyze a sample of fainter [OII] emitting galaxies found in the Subaru Deep Field (SDF). We find an extinction-corrected [OII] luminosity density of 10Exp(40.35^+0.08^_-0.06_)^erg/s/Mpc^3^, corresponding to star formation rate density of 0.32^+0.06^_-0.04_ M_{sun}_/yr/Mpc^3^ in the COSMOS field at z~1.2. This is the largest survey for [OII] emitters beyond z=1 currently available.
The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) pilot survey identified 284 [OII]{lambda}3727 emitting galaxies in a 169arcmin^2^ field of sky in the redshift range 0<z<0.57. This line flux limited sample provides a bridge between studies in the local universe and higher-redshift [OII] surveys. We present an analysis of the star formation rates (SFRs) of these galaxies as a function of stellar mass as determined via spectral energy distribution fitting. The [OII] emitters fall on the "main sequence" of star-forming galaxies with SFR decreasing at lower masses and redshifts. However, the slope of our relation is flatter than that found for most other samples, a result of the metallicity dependence of the [OII] star formation rate indicator. The mass-specific SFR is higher for lower mass objects, supporting the idea that massive galaxies formed more quickly and efficiently than their lower mass counterparts. This is confirmed by the fact that the equivalent widths of the [OII] emission lines trend smaller with larger stellar mass. Examination of the morphologies of the [OII] emitters reveals that their star formation is not a result of mergers, and the galaxies' half-light radii do not indicate evolution of physical sizes.
We present the [OII] luminosity function measured in the redshift range 0.1<z<1.65 with unprecedented depth and accuracy. Our measurements are based on medium resolution flux-calibrated spectra of emission line galaxies with the FORS2 instrument at VLT and with the SDSS-III/BOSS spectrograph. The FORS2 spectra and the corresponding catalog containing redshifts and line fluxes are released along with this paper. In this work we use a novel method to combine the aforementioned surveys with GAMA, zCOSMOS and VVDS, which have different target selection, producing a consistent weighting scheme to derive the [OII] luminosity function. The measured luminosity function is in good agreement with previous independent estimates. The comparison with two state-of-the-art semi-analytical models is good, which is encouraging for the production of mock catalogs of [OII] flux limited surveys. We observe the bright end evolution over 8.5Gyr: we measure the decrease of logL* from 42.4erg/s at redshift 1.44 to 41.2 at redshift 0.165 and we find that the faint end slope flattens when redshift decreases. This measurement confirms the feasibility of the target selection of future baryonic acoustic oscillation surveys aiming at observing [OII] flux limited samples.
The WIde-field Nearby Galaxy-cluster Survey (WINGS) is a wide-field and multiwavelength survey of 76 galaxy clusters in the local Universe. The sample consists of all clusters at 0.04<z<0.07 in both hemispheres at Galactic latitude |b|>20 selected from the ROSAT X-ray-Brightest Abell-type Cluster Sample, the Brightest Cluster Sample, and its extension. The original WINGS survey is based on B and V imaging for the 76 clusters over a 34 by 34 arcminute field of view taken with the Wide Field Cameras on the INT and the 2.2m MPG/ESO telescopes. With the aim to cover the virial region and extend out into the infall region, we have obtained GTO OmegaCAM imaging in the B, and V bands over 1 by 1 degree for 45 fields covering 46 WINGS clusters. We present the Johnson B- and V-band OmegaCAM photometry of 46 WINGS clusters. With a median seeing of 1 arcsecond in both B- and V-bands, our 25-minutes exposures in each band typically reach the 50% completeness level at V=23.1mag.
We aim at defining homogeneous selection criteria of small galaxy systems in order to build catalogues suitable to compare main properties of pairs, triplets, and groups with four or more members. To this end we use spectroscopic and photometric Sloan Digital Sky Survey (SDSS) data to identify systems with a low number of members. We study global properties of these systems and the properties of their member galaxies finding that galaxies in groups are systematically redder and with lower star formation activity indicators than galaxies in pairs which have a higher fraction of star-forming galaxies. Triplet galaxies present intermediate trends between pairs and groups. We also find an enhancement of star formation activity for galaxies in small systems with companions closer than 100kpc, irrespective of the number of members. We have tested these analyses on SDSS mock catalogues derived from the Millennium simulation, finding as conservative thresholds 76 per cent completeness and a contamination of 23 per cent in small galaxy systems, when considering an extreme case of incompleteness due to fiber collisions. Nevertheless, we also found that the results obtained are not likely affected by projection effects. Our studies suggest that an extra galaxy in a system modify the properties of the member galaxies. In pairs, galaxy-galaxy interactions increase gas density and trigger starbursts. However, repeated interactions in triplets and groups can generate gas stripping, turbulence, and shocks quenching the star formation in these systems.
The results are reported of an objective-prism survey of stars, mostly earlier than spectral type F5, for two fields at (l;b) = (90 deg and 270 deg; -45 deg). The fields, each of approximately 70 square degrees, are examined on plates taken with the Schmidt Telescope of the Anglo-Australian Observatory. The brightness range of the stars classified is 10 < V < 15. The prism combination used provides a dispersion of 600 A/mm at Hgamma. The spectral classification presented is defined by the equality of equivalent widths of Ca II K and Hdelta at type "F0" and the absence of Ca II K in stars with significant Balmer lines at type "A0". Positions listed in the catalog were measured on the Stromlo PDS microdensitometer. Most stars were subsequently identified with objects in the ST ScI-NASA-ESO Hubble Space Telescope Guide Star Catalog in which positions have an accuracy of near +/- 1.0 arcsec.
We have carefully selected a sample of 60 galaxies that reside in the deepest underdensities of geometrically identified voids within the Sloan Digital Sky Survey. HI imaging of 55 galaxies with the Westerbork Synthesis Radio Telescope reveals morphological and kinematic signatures of ongoing interactions and gas accretion. We probe a total volume of 485Mpc^3^ within the voids, with an angular resolution of 8kpc at an average distance of 85Mpc. We reach column density sensitivities of 5x10^19^/cm^-2^, corresponding to an HI mass limit of 3x10^8^M_{sun}_. We detect HI in 41 galaxies, with total masses ranging from 1.7x10^8^ to 5.5x10^9^M_{sun}_. The upper limits on the 14 non-detections are not inconsistent with their luminosities, given their expected HI mass-to-light ratios. We find that the void galaxies are generally gas-rich, low-luminosity, blue disk galaxies, with optical and HI properties that are not unusual for their luminosity and morphology. The sample spans a range of absolute magnitudes (-16.1>M_r_>-20.4) and colors (0.06<g-r<0.87), and includes disk and irregular galaxies. We also identify three as early-type galaxies, all of which are not detected in HI. All galaxies have stellar masses less than 3x10^10^M_{sun}_, and many have kinematic and morphological signs of ongoing gas accretion, suggesting that the void galaxy population is still in the process of assembling. The small-scale clustering in the void, within 600kpc and 200km/s, is similar to that in higher density regions, and we identify 18 HI-rich neighboring galaxies in the voids. Most are within 100kpc and 100km/s of the targeted galaxy, and we find no significant population of HI-rich low-luminosity galaxies filling the voids, contrary to what is predicted by simulations.
