The catalog contains a list of 412 faint galaxies selected for their apparent ultraviolet excess. The galaxies were selected from a 3-color (UBV) plate taken with the Palomar 48-inch Schmidt telescope. The 14-inch-square plates cover an area of 30 square degrees centered on Kapteyn Selected Area 28. The catalog includes running numbers, coordinates, color codes, magnitude codes, morphologies, diameters, and notes. The catalogued galaxies were selected by eye from the Palomar Schmidt 3-color (UBV) plate PS24771, centered on Kapteyn Selexted Area 28 and taken by Usher under conditions of good seeing and transparency.
Interstellar extinction in ultraviolet is the most severe in comparison with optical and infrared wavebands and a precise determination plays an important role in correctly recovering the ultraviolet brightness and colors of objects. By finding the observed bluest colors at the given effective temperature and metallicity range of dwarf stars, stellar intrinsic colors, C_B,V_^0^, C_NUV,B_^0^, C_FUV,B_^0^, and C_FUV,NUV_^0^, are derived according to the stellar parameters from the LAMOST spectroscopic survey and photometric results from the GALEX and APASS surveys. With the derived intrinsic colors, the ultraviolet color excesses are calculated for about 25,000 A- and F-type dwarf stars. Analysis of the color excess ratios yields the extinction law related to the GALEX UV bands: E_NUV,B_/E_B,V_=3.77, E_FUV,B_/E_B,V_=3.39, and E_FUV,NUV_/E_B,V_=-0.38. The results agree very well with previous works in the NUV band and in general with the extinction curve derived by Fitzpatrick (1999PASP..111...63F) for R_V_=3.35.
The Ultraviolet Imaging Telescope UIT was one of three ultraviolet telescopes on the ASTRO-1 mission flown on the space shuttle Columbia during 2-10 December 1990. The same three instruments were later flown on the space shuttle Endeavour from 3-17 March 1995, as part of the ASTRO-2 mission. Exposures were obtained on 70-mm photographic film in the 1200-3300 Å range using broadband filters and later digitized using a Perkin-Elmer microdensitometer. Image resolution was 3" over a 40' field of view. Overall, UIT-1 obtained 821 exposures of 66 targets, and UIT-2 obtained 758 images of 193 targets.
The Ultraviolet Imaging Telescope (UIT) was one of three ultraviolet telescopes on the ASTRO-1 mission flown on the Space Shuttle Columbia during the period of 2 - 10 December 1990. The same three instruments were later flown on the Space Shuttle Endeavour during 3 - 17 March 1995, as part of the ASTRO-2 mission. Exposures were obtained on 70-mm photographic film in the 1200-3300 Angstrom range using broadband filters and later digitized using a Perkin-Elmer microdensitometer. The image resolution was 3 arcseconds over a 40 arcminute field of view and images of targets as faint as 21st (ultraviolet) magnitude were recorded. Overall, the UIT-1 mission obtained 821 exposures of 66 targets (361 near-UV and 460 far-UV), and UIT-2 obtained 758 images of 193 targets (all far-UV), for a total of 1579 exposures. This table contains only 1481 rows, 777 UIT-1 exposures (347 near-UV and 430 far-UV) and 704 UIT-2 exposures (all far-UV), implying that 98 exposures are 'missing' from this table. This table was created by the HEASARC in April 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/VI/104">CDS Catalog VI/104</a> file uitlist.dat. This is a service provided by NASA HEASARC .
The Ultraviolet Imaging Telescope (UIT) Near-UV Bright Objects Catalog is a photometric catalog of 2244 objects detected by the UIT in the near-ultraviolet (NUV; 1650A<lambda<2900A) during the Astro-1 Space Shuttle mission. Sources in the catalog are as faint as near-UV magnitude m_nuv of about 18.8, or near-UV flux f_nuv ~ 1.1x10<sup>-16ergs/s/cm</sup>2/A, but the survey is not complete to this level. Optical catalogs were used to cross identify sources and derive near-UV to Johnson V colors. A majority of the objects (88%) do indeed have proposed optical identifications from catalogs, and most are stars. The authors' purpose in creating the catalog was to form a database useful for identifying very blue objects and for performing Galactic UV stellar population studies. This database was created by the HEASARC in November 2000 based on a machine-readable version obtained from the CDS (Catalog J/ApJS/104/287). This is a service provided by NASA HEASARC .
The Ultraviolet Imaging Telescope UIT was one of three ultraviolet telescopes on the ASTRO-1 mission flown on the space shuttle Columbia during 2-10 December 1990. The same three instruments were later flown on the space shuttle Endeavour from 3-17 March 1995, as part of the ASTRO-2 mission. Exposures were obtained on 70-mm photographic film in the 1200-3300 Å range using broadband filters and later digitized using a Perkin-Elmer microdensitometer. Image resolution was 3" over a 40' field of view. Overall, UIT-1 obtained 821 exposures of 66 targets, and UIT-2 obtained 758 images of 193 targets.
We have selected spectra of 232 stars from the IUE archives for inclusion in an atlas intended for various uses but tailored especially for the study of stellar winds. The atlas covers the range in spectral types from O3 to F8. The full atlas covers the reduced and normalized high resolution spectra from the IUE long- and short-wavelength spectrographs. Here we discuss the selection of the stars and the data reduction, and we present in velocity units the profiles of lines formed in the stellar winds. The selected lines cover a wide range of ionizations, allowing a comparison of the profiles from different ions in the wind of each star and a comparison of the different wind lines as a function of spectral type and luminosity. We also present the basic data on the program stars to facilitate study of the dependence of wind features on stellar parameters such as luminosity, temperature, escape velocity, and v sin i. We provide an overview of the characteristic behavior of the wind lines in the H-R diagram. The complete spectra are available in digital form through the NASA Astrophysics Data System (ADS). We offer a description of the electronic database that is available through the ADS and guidelines for obtaining access to that database.
We present a sample of spectroscopically confirmed quasi-stellar objects (QSOs) with FUV-NUV color (as measured by Galaxy Evolution Explorer (GALEX) photometry, FUV band: 1344-1786{AA}, NUV band: 1771-2831{AA}) bluer than canonical QSO templates and than the majority of known QSOs. We analyze their FUV to NIR colors, luminosities, and optical spectra. The sample includes a group of 150 objects at low redshift (z<0.5), and a group of 21 objects with redshift 1.7<z<2.6.
The first observations of the ultraviolet spectrum of the binary system VV Cep (M2Iab + B?) during total eclipse have been made with the HST. A rich emission-line spectrum is seen, with over two thousand emission features present. Shortward of 1600{AA}, a weak continuum presumably due to Rayleigh scattering of the hot component is present, strengthening markedly shortward of 1500{AA}. The continuum of the M supergiant becomes apparent longward of 2650{AA}. Numerous circumstellar and interstellar absorption features are also seen. We present an atlas of the spectrum from 1300-3160{AA} as observed near midtotality and at two epochs closer to egress, when gas surrounding the hot component has begun to emerge from eclipse and the flux on the short-wavelength edges of many emission lines has increased. This atlas has been annotated with line identifications. Circumstellar and interstellar absorption features seen out of eclipse remain in absorption during totality and are also annotated on the atlas. Well over 90% of the emission features have plausible identifications, but there are many blends. Only a few hundred features appear to be free enough from blending for useful measurement of the peak flux in the line. We present a list of these unblended features.
