- ID:
- ivo://nasa.heasarc/uit
- Title:
- Ultraviolet Imaging Telescope Near-UV Bright Objects Catalog
- Short Name:
- UIT
- Date:
- 21 Feb 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- 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 .
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21962. Ultraviolet P Cygni profiles
- ID:
- ivo://CDS.VizieR/J/ApJS/95/163
- Title:
- Ultraviolet P Cygni profiles
- Short Name:
- J/ApJS/95/163
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 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.
- ID:
- ivo://CDS.VizieR/J/AJ/137/3761
- Title:
- Ultraviolet quasi-stellar objects
- Short Name:
- J/AJ/137/3761
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 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.
- ID:
- ivo://CDS.VizieR/J/ApJS/171/249
- Title:
- Ultraviolet Spectral Atlas of VV Cephei
- Short Name:
- J/ApJS/171/249
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 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.
- ID:
- ivo://CDS.VizieR/J/A+AS/113/237
- Title:
- Ultraviolet Spectrum of the Sun
- Short Name:
- J/A+AS/113/237
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An ultraviolet atlas of the solar spectrum with a spectral resolution of 15mA in the region 1948-2000A is presented. It is the first part of the spectra recorded on the quiet Sun between 1900 and 2130A. Measurements were performed from a balloon-borne instrumentation flown at an altitude of 39km. The wavelength atlas with a list of about 550 lines has been synthesized from data at center of the Sun ({mu}=1) and at {mu}=0.89, smoothed out over an area of 30 arcsec. The wavelength scale is given with respect to the average solar spectrum. Tracings are presented at {mu}=0.89, with an intensity scale adjusted in absolute values on the level of the continuum near 2000A.
- ID:
- ivo://CDS.VizieR/J/ApJS/247/47
- Title:
- Ultraviolet survey of M31 with UVIT on AstroSat
- Short Name:
- J/ApJS/247/47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An ultraviolet survey of M31 has been carried out during 2017-19 with the UltraViolet Imaging Telescope (UVIT) instrument on board the AstroSat Observatory. Here we analyze far- and near-ultraviolet (FUV and NUV) observations from the M31 UVIT survey, which covers a sky area of ~3{deg}x1{deg} with spatial resolution of ~1". The observations included six filter bands in the wavelength range of 120-280nm. The limiting magnitude (AB) in the FUV band (CaF2 filter), which has the largest number of detected sources, is ~23. The primary product of this work is the M31 UVIT point-source catalog containing positions and photometry. In total ~75000 sources were detected at FUV or NUV wavelengths.
- ID:
- ivo://CDS.VizieR/J/A+A/544/A156
- Title:
- UltraVISTA Catalogue Release DR1
- Short Name:
- J/A+A/544/A156
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we describe the first data release of the UltraVISTA near-infrared imaging survey of the COSMOS field. We summarise the key goals and design of the survey and provide a detailed description of our data reduction techniques. We provide stacked, sky-subtracted images in Y JHKs and narrow-band filters constructed from data collected during the first year of UltraVISTA observations.
- ID:
- ivo://CDS.VizieR/J/MNRAS/446/470
- Title:
- ULX candidates in luminous infrared galaxies
- Short Name:
- J/MNRAS/446/470
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a Chandra study of ultraluminous X-ray sources (ULXs) in a sample of 17 nearby (D_L_<60Mpc) luminous infrared galaxies (LIRGs), selected to have star formation rates (SFRs) in excess of 7M_{sun}_/yr and low foreground Galactic column densities (N_H_<~5x10^20^cm^-2^). A total of 53 ULXs were detected and we confirm that this is a complete catalogue of ULXs for the LIRG sample. We examine the evolution of ULX spectra with luminosity in these galaxies by stacking the spectra of individual objects in three luminosity bins, finding a distinct change in spectral index at luminosity ~2x10^39^erg/s. This may be a change in spectrum as 10M_{sun}_ black holes transit from an ~ Eddington to a super-Eddington accretion regime, and is supported by a plausible detection of partially ionized absorption imprinted on the spectrum of the luminous ULX (L_X_~5x10^39^erg/s) CXOU J024238.9-000055 in NGC 1068, consistent with the highly ionized massive wind that we would expect to see driven by a super-Eddington accretion flow. This sample shows a large deficit in the number of ULXs detected per unit SFR (0.2 versus 2 ULXs, per M_{sun}_/yr) compared to the detection rate in nearby (D_L_<14.5Mpc) normal star-forming galaxies. This deficit also manifests itself as a lower differential X-ray luminosity function normalization for the LIRG sample than for samples of other star-forming galaxies. We show that it is unlikely that this deficit is a purely observational effect. Part of this deficit might be attributable to the high metallicity of the LIRGs impeding the production efficiency of ULXs and/or a lag between the star formation starting and the production of ULXs; however, we argue that the evidence - including very low N_ULX_/L_FIR_, and an even lower ULX incidence in the central regions of the LIRGs - shows that the main culprit for this deficit is likely to be the high column of gas and dust in these galaxies, that fuels the high SFR but also acts to obscure many ULXs from our view.
- ID:
- ivo://CDS.VizieR/J/AJ/143/144
- Title:
- ULX candidates in nearby Arp galaxies
- Short Name:
- J/AJ/143/144
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted a statistical analysis of the ultra-luminous X-ray point sources (ULXs; L_X_>=10^39^erg/s) in a sample of galaxies selected from the Arp Atlas of Peculiar Galaxies (1996, Cat. VII/192; Webb, 1996, Cat. VII/192). We find a possible enhancement of a factor of ~2-4 in the number of ULXs per blue luminosity for the strongly interacting subset. Such an enhancement would be expected if ULX production is related to star formation, as interacting galaxies tend to have enhanced star formation rates on average. For most of the Arp galaxies in our sample, the total number of ULXs compared to the far-infrared luminosity is consistent with values found earlier for spiral galaxies. This suggests that for these galaxies, ULXs trace recent star formation. However, for the most infrared-luminous galaxies, we find a deficiency of ULXs compared to the infrared luminosity. For these very infrared-luminous galaxies, active galactic nuclei may contribute to powering the far-infrared; alternatively, ULXs may be highly obscured in the X-ray in these galaxies and therefore not detected by these Chandra observations. We determined local UV/optical colors within the galaxies in the vicinity of the candidate ULXs using Galaxy Evolution Explorer UV and Sloan Digitized Sky Survey optical images. In most cases, the distributions of colors are similar to the global colors of interacting galaxies. However, the u-g and r-i colors at the ULX locations tend to be bluer on average than these global colors, suggesting that ULXs are preferentially found in regions with young stellar populations. In the Arp sample there is a possible enhancement of a factor of ~2-5 in the fraction of galactic nuclei that are X-ray-bright compared to more normal spirals.
- ID:
- ivo://CDS.VizieR/J/ApJ/741/49
- Title:
- ULX candidates in nearby galaxies
- Short Name:
- J/ApJ/741/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- One hundred seven ultraluminous X-ray sources (ULXs) with 0.3-10.0keV luminosities in excess of 10^39^erg/s are identified in a complete sample of 127 nearby galaxies. The sample includes all galaxies within 14.5Mpc above the completeness limits of both the Uppsala Galaxy Catalogue (Cat. VII/26) and the Infrared Astronomical Satellite survey (Cat. II/125). The galaxy sample spans all Hubble types, a four-decade range in mass, 7.5<log(M/M_{sun}_)<11.4, and in star formation rate, 0.0002<SFR(M_{sun}_/yr)<=3.6. ULXs are detected in this sample at rates of one per 3.2x10^10^M_{sun}_, one per ~0.5M_{sun}_/yr star formation rate, and one per 57Mpc^3^ corresponding to a luminosity density of ~2x10^37^erg/s/Mpc^3^. At these rates we estimate as many as 19 additional ULXs remain undetected in fainter dwarf galaxies within the survey volume. An estimated 14 objects, or 13%, of the 107 ULX candidates are expected to be background sources. The differential ULX luminosity function shows a power-law slope {alpha}~-0.8 to -2.0 with an exponential cutoff at ~20x10^39^erg/s with precise values depending on the model and on whether the ULX luminosities are estimated from their observed numbers of counts or, for a subset of candidates, from their spectral shapes. Extrapolating the observed luminosity function predicts at most one very luminous ULX, L_X_~10^41^erg/s, within a distance as small as 100Mpc. The luminosity distribution of ULXs within the local universe cannot account for the recent claims of luminosities in excess of 2x10^41^erg/s, requiring a new population class to explain these extreme objects.
