The VLT Survey Telescope ATLAS survey is an optical ugriz survey aiming to cover ~4700deg^2^ of the southern sky to similar depths as the Sloan Digital Sky Survey (SDSS). From reduced images and object catalogues provided by the Cambridge Astronomical Surveys Unit, we first find that the median seeing ranges from 0.8-arcsec FWHM (full width at half-maximum) in i to 1.0-arcsec in u, significantly better than the 1.2-1.5arcsec seeing for SDSS. The 5{sigma} mag limit for stellar sources is r_AB_=22.7 and in all bands these limits are at least as faint as SDSS. SDSS and ATLAS are more equivalent for galaxy photometry except in the z band where ATLAS has significantly higher throughput. We have improved the original ESO magnitude zero-points by comparing m<16 star magnitudes with the AAVSO Photometric All-Sky Survey in gri, also extrapolating into u and z, resulting in zero-points accurate to ~+/-0.02mag. We finally compare star and galaxy number counts in a 250deg^2^ area with SDSS and other count data and find good agreement. ATLAS data products can be retrieved from the ESO Science Archive, while support for survey science analyses is provided by the OmegaCAM Science Archive, operated by the Wide-Field Astronomy Unit in Edinburgh.
We present the full data set of the VIsible Multi-Object Spectrograph (VIMOS) spectroscopic campaign of the ESO/GOODS program in the Chandra Deep Field South (CDFS), which complements the FORS2 ESO/GOODS spectroscopic campaign. The ESO/GOODS spectroscopic programs are aimed at reaching signal-to-noise ratios adequate to measure redshifts for galaxies with AB magnitudes in the range ~24-25 in the B and R band using VIMOS, and in the z band using FORS2.
We present VLT/X-shooter spectroscopic observations in the wavelength range {lambda}{lambda}3000-23000{AA} of the extremely metal-deficient blue compact dwarf (BCD) galaxy PHL 293B containing a luminous blue variable (LBV) star and compare them with previous data. This BCD is one of the two lowest-metallicity galaxies where LBV stars were detected, allowing us to study the LBV phenomenon in the extremely low metallicity regime. We determine abundances of nitrogen, oxygen, neon, sulfur, argon, and iron by analyzing the fluxes of narrow components of the emission lines using empirical methods and study the properties of the LBV from the fluxes and widths of broad emission lines.
Distant luminous Lyman-{alpha} emitters (LAEs) are excellent targets for spectroscopic observations of galaxies in the epoch of reionisation (EoR). We present deep high-resolution (R=5000) VLT/X-shooter observations, along with an extensive collection of photometric data of COLA1, a proposed double peaked LAE at z=6.6. We rule out the possibility that COLA1's emission line is an [OII] doublet at z=1.475 on the basis of i) the asymmetric red line-profile and flux ratio of the peaks (blue/red=0.31+/-0.03) and ii) an unphysical [OII]/H{alpha} ratio ([OII]/H{alpha}>22). We show that COLA1's observed B-band flux is explained by a faint extended foreground LAE, for which we detect Ly{alpha} and [OIII] at z=2.142. We thus conclude that COLA1 is a real double-peaked LAE at z=6.593, the first discovered at z>6. COLA1 is UV luminous (M1500=-21.6+/-0.3), has a high equivalent width (EW0,Ly{alpha}=120_-40_^+50^{AA}) and very compact Ly{alpha} emission (r50,Ly{alpha}=0.33_-0.04_^+0.07^kpc). Relatively weak inferred H{beta}+[OIII] line-emission from Spitzer/IRAC indicates an extremely low metallicity of Z<1/20Z_{sun}_ or reduced strength of nebular lines due to high escape of ionising photons. The small Ly{alpha} peak separation of 220+/-20km/s implies a low HI column density and an ionising photon escape fraction of ~15-30%, providing the first direct evidence that such galaxies contribute actively to the reionisation of the Universe at z>6. Based on simple estimates, we find that COLA1 could have provided just enough photons to reionise its own ~0.3pMpc (2.3cMpc) bubble, allowing the blue Ly{alpha} line to be observed. However, we also discuss alternative scenarios explaining the detected double peaked nature of COLA1. Our results show that future high-resolution observations of statistical samples of double peaked LAEs at z>5 are a promising probe of the occurrence of ionised regions around galaxies in the EoR.
In this paper, relation was established for Hyades stars between their apparent magnitudes and parallaxes. The precision criteria of this relation are very satisfactory. The importance of this relation was illustrated through its usages as: (1) A criterion for membership of the cluster, (2) a generating function for evaluating some parameters of the cluster.
WFAU, Institute for Astronomy, University of Edinburgh
Description:
The VMC survey aims to obtain YJKs band photometry across the system down to Ks=20.3 at S/N=10. This sensitivity corresponds to the bottom of the red giant branch field stellar population and allows us to determine the global spatially resolved star formation history with unprecedented quality and to construct a three-dimensional map of the system. A wide-area encompassing the D25 as well as major features delineated by the distribution of stars and HI gas, will both trace the structure of the galaxies and signatures of past and present interactions. Contemporary optical and kinematic observations of comparable sensitivity will provide the community with a superior database for future studies of the system and will give us an excellent insight as to what has happened elsewhere in the Universe.
WFAU, Institute for Astronomy, University of Edinburgh
Description:
The VMC survey aims to obtain YJKs band photometry across the system down to Ks=20.3 at S/N=10. This sensitivity corresponds to the bottom of the red giant branch field stellar population and allows us to determine the global spatially resolved star formation history with unprecedented quality and to construct a three-dimensional map of the system. A wide-area encompassing the D25 as well as major features delineated by the distribution of stars and HI gas, will both trace the structure of the galaxies and signatures of past and present interactions. Contemporary optical and kinematic observations of comparable sensitivity will provide the community with a superior database for future studies of the system and will give us an excellent insight as to what has happened elsewhere in the Universe.
WFAU, Institute for Astronomy, University of Edinburgh
Description:
The VMC survey aims to obtain YJKs band photometry across the system down to Ks=20.3 at S/N=10. This sensitivity corresponds to the bottom of the red giant branch field stellar population and allows us to determine the global spatially resolved star formation history with unprecedented quality and to construct a three-dimensional map of the system. A wide-area encompassing the D25 as well as major features delineated by the distribution of stars and HI gas, will both trace the structure of the galaxies and signatures of past and present interactions. Contemporary optical and kinematic observations of comparable sensitivity will provide the community with a superior database for future studies of the system and will give us an excellent insight as to what has happened elsewhere in the Universe.
WFAU, Institute for Astronomy, University of Edinburgh
Description:
The VMC survey aims to obtain YJKs band photometry across the system down to Ks=20.3 at S/N=10. This sensitivity corresponds to the bottom of the red giant branch field stellar population and allows us to determine the global spatially resolved star formation history with unprecedented quality and to construct a three-dimensional map of the system. A wide-area encompassing the D25 as well as major features delineated by the distribution of stars and HI gas, will both trace the structure of the galaxies and signatures of past and present interactions. Contemporary optical and kinematic observations of comparable sensitivity will provide the community with a superior database for future studies of the system and will give us an excellent insight as to what has happened elsewhere in the Universe.
WFAU, Institute for Astronomy, University of Edinburgh
Description:
The VMC survey aims to obtain YJKs band photometry across the system down to Ks=20.3 at S/N=10. This sensitivity corresponds to the bottom of the red giant branch field stellar population and allows us to determine the global spatially resolved star formation history with unprecedented quality and to construct a three-dimensional map of the system. A wide-area encompassing the D25 as well as major features delineated by the distribution of stars and HI gas, will both trace the structure of the galaxies and signatures of past and present interactions. Contemporary optical and kinematic observations of comparable sensitivity will provide the community with a superior database for future studies of the system and will give us an excellent insight as to what has happened elsewhere in the Universe.
