- ID:
- ivo://CDS.VizieR/J/MNRAS/385/2097
- Title:
- NUV-J colours of red-sequence galaxies
- Short Name:
- J/MNRAS/385/2097
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present GALEX near-ultraviolet (NUV) and Two-Micron All-Sky Survey J-band photometry for red-sequence galaxies in local clusters. We define quiescent samples according to a strict emission threshold, removing galaxies with very recent star formation. We analyse the NUVJ colour-magnitude relation (CMR) and find that the intrinsic scatter is an order of magnitude larger than for the analogous optical CMR (~0.35 rather than 0.05mag), in agreement with previous studies. Comparing the NUVJ colours with spectroscopically derived stellar population parameters, we find a strong (>5.5sigma) correlation with metallicity, only a marginal trend with age, and no correlation with the alpha/Fe ratio. We explore the origin of the large scatter and conclude that neither aperture effects nor the UV upturn phenomenon contribute significantly. We show that the scatter could be attributed to simple 'frosting' by either a young or a low-metallicity subpopulation.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/132/2014
- Title:
- NUV sources in CDF-S and HDF-N GOODS fields
- Short Name:
- J/AJ/132/2014
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an ultraviolet-selected sample of 268 objects in the two fields of the Great Observatories Origins Deep Survey (GOODS). We used the parallel observations taken with the Wide Field Planetary Camera 2 in the U band (F300W), which covered 88% of the GOODS fields, to identify sources and selected only objects with GOODS Advanced Camera for Surveys counterparts. Spectroscopic redshifts for 95 of these sources are available, and we have used the multiwavelength GOODS data to estimate photometric redshifts for the others. Most of the objects have redshifts 0.2<z<0.8. We used the spectral types obtained by photometric redshift fitting to identify starburst galaxies. We have also visually checked all objects and looked for tidal effects and nearby companions.
- ID:
- ivo://CDS.VizieR/J/AJ/138/598
- Title:
- NUV sources in Hubble Ultra Deep Field
- Short Name:
- J/AJ/138/598
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog from the first high-resolution U-band image of the Hubble Ultra Deep Field, taken with Hubble's Wide-Field Planetary Camera 2 through the F300W filter, is presented. We detect 96 U-band objects and compare and combine this catalog with a Great Observatories Origins Deep Survey B-selected catalog that provides B, V, i, and z photometry, spectral types, and photometric redshifts. We have also obtained far-ultraviolet (FUV, 1614{AA}) data with Hubble's Advanced Camera for Surveys Solar Blind Channel (ACS/SBC) and with GALEX. We detected 31 sources with ACS/SBC, 28 with GALEX/FUV, and 45 with GALEX/NUV. The methods of observations, image processing, object identification, catalog preparation, and catalog matching are presented.
- ID:
- ivo://CDS.VizieR/J/A+AS/105/305
- Title:
- OB stars observed with high dispersion by IUE
- Short Name:
- J/A+AS/105/305
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An atlas on microfiche is described containing nearly 7000 high-dispersion spectra of OB stars obtained during the first 10 years with the IUE satellite. The data set is nearly complete for the selected time interval. The plotted wavelength range is from 1160 to 1890 A at the original IUE sampling intervals. The atlas is available by request.
- ID:
- ivo://CDS.VizieR/J/ApJ/872/55
- Title:
- OI, GeII, KrI & H abundances from HST UV spectra
- Short Name:
- J/ApJ/872/55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In a survey of archived ultraviolet spectra of 100 stars recorded by the echelle spectrograph of the Space Telescope Imaging Spectrograph on the Hubble Space Telescope, we measure the strengths of the weak absorption features of OI, GeII, and KrI in the interstellar medium. Our objective is to undertake an investigation that goes beyond earlier abundance studies to see how these elements are influenced independently by three different environmental properties: (1) values of a generalized atomic depletion factor F_*_ due to condensations onto dust grains (revealed here by the abundances of Mg and Mn relative to H), (2) the fraction of H atoms in the form of H_2_/f(H_2_), and (3) the ambient intensity I of ultraviolet starlight relative to an average value in our part of the Galaxy I_0_. As expected, the gas-phase abundances of all three elements exhibit negative partial correlations with F*. The abundances of free O atoms show significant positive partial correlations with logf(H_2_) and log(I/I_0_), while Ge and Kr exhibit negative partial correlations with log(I/I_0_) at marginal levels of significance. After correcting for these trends, the abundances of O relative to H show no significant variations with location, except for the already-known radial gradient of light-element abundances in the Milky Way. A comparison of Ge and O abundances revealed no significant regional enhancements or deficiencies of neutron-capture elements relative to {alpha}-process ones.
- ID:
- ivo://CDS.VizieR/J/ApJ/596/768
- Title:
- Optical depths in 19 QSOs
- Short Name:
- J/ApJ/596/768
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We measure the distribution of carbon in the intergalactic medium as a function of redshift z and overdensity {delta}. Using a hydrodynamical simulation to link the H I absorption to the density and temperature of the absorbing gas, and a model for the UV background radiation, we convert ratios of C IV to H I pixel optical depths into carbon abundances. For the median metallicity this technique was described and tested in Paper I (Aguirre et al., 2002ApJ...576....1A) of this series. Here we generalize it to reconstruct the full probability distribution of the carbon abundance and apply it to 19 high-quality quasar absorption spectra.
- ID:
- ivo://CDS.VizieR/J/A+A/561/A89
- Title:
- Optical spectroscopy of 24 Ly-alpha emitters
- Short Name:
- J/A+A/561/A89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Among the different observational techniques used to select high-redshift galaxies, the hydrogen recombination line Lyman-alpha (Ly{alpha}) is of particular interest because it gives access to the measurement of cosmological quantities such as the star formation rate (SFR) of distant galaxy populations. However, interpreting this line and calibrating such observables are still subject to serious uncertainties. In this context, it important to understand the mechanisms responsible for the attenuation of Ly{alpha} emission, and under what conditions the Ly{alpha} emission line can be used as a reliable star formation diagnostic tool. We used a sample of 24 Ly{alpha} emitters at z~0.3 with an optical spectroscopic follow-up to calculate the Ly{alpha} escape fraction and its dependence upon different physical properties. We also examined the reliability of Ly{alpha} as a SFR indicator. We combined these observations with a compilation of Ly{alpha} emitters selected at z=0-0.3 from the literature to assemble a larger sample.
- ID:
- ivo://CDS.VizieR/J/ApJS/146/1
- Title:
- O VI absorption in FUSE survey
- Short Name:
- J/ApJS/146/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Far Ultraviolet Spectroscopic Explorer (FUSE) observations of the O VI {lambda}{lambda}1031.926, 1037.617 absorption lines associated with gas in and near the Milky Way, as detected in the spectra of a sample of 100 extragalactic targets and two distant halo stars. We combine data from several FUSE Science Team programs with guest observer data that were public before 2002 May 1. The sight lines cover most of the sky above Galactic latitude |b|>25{deg}, at lower latitude the ultraviolet extinction is usually too large for extragalactic observations.
- ID:
- ivo://CDS.VizieR/J/ApJS/146/125
- Title:
- O VI in the galactic halo
- Short Name:
- J/ApJS/146/125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Far-Ultraviolet Spectroscopic Explorer (FUSE) spectra of 100 extragalactic objects and two distant halo stars are analyzed to obtain measures of O VI {lambda}{lambda}1031.93, 1037.62 absorption along paths through the Milky Way thick disk/halo.
- ID:
- ivo://CDS.VizieR/J/ApJ/695/580
- Title:
- Oxygen abundance in M83
- Short Name:
- J/ApJ/695/580
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained deep multiobject optical spectra of 49 HII regions in the outer disk of the spiral galaxy M83 (=NGC 5236) with the FORS2 spectrograph at the Very Large Telescope. The targets span the range in galactocentric distance between 0.64 and 2.64 times the R_25_ isophotal radius (5.4-22.3kpc), and 31 of them are located at R>R_25_, thus belonging to the extreme outer disk of the galaxy, populated by UV complexes revealed recently by the Galaxy Evolution Explorer satellite. In order to derive the nebular chemical abundances, we apply several diagnostics of the oxygen abundance, including R_23_, [NII]/[OII], and the [OIII]{lambda}4363 auroral line, which was detected in four HII regions.
