- ID:
- ivo://CDS.VizieR/J/A+A/385/986
- Title:
- FUSE UV spectrum of HR 5223
- Short Name:
- J/A+A/385/986
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New spectra have been obtained for the pole-on Be star HR 5223 (HD 120991) using the Far Ultraviolet Satellite Explorer (FUSE). We give a complete description of the far-UV spectral range (920 to 1180{AA}). The spectra are affected by strong blends with interstellar lines and molecular bands that also significantly lower the energy distribution of the star. We produce a synthetic spectrum of the interstellar medium (ISM) to determine the column densities of several elements (H_2_, H I, N I, O I ...) seen towards HR 5223 and to disentangle the components due to the ISM, the photosphere and/or to the circumstellar envelope.
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- ID:
- ivo://CDS.VizieR/J/AJ/162/126
- Title:
- FUV and optical absorption in 47 Tucanae
- Short Name:
- J/AJ/162/126
- Date:
- 14 Mar 2022 08:43:21
- Publisher:
- CDS
- Description:
- The Bright Star in the globular cluster 47Tucanae (NGC104) is a post-asymptotic giant branch (post-AGB) star of spectral type B8III. The ultraviolet spectra of late-B stars exhibit myriad absorption features, many due to species unobservable from the ground. The Bright Star thus represents a unique window into the chemistry of 47Tuc. We have analyzed observations obtained with the Far Ultraviolet Spectroscopic Explorer, the Cosmic Origins Spectrograph aboard the Hubble Space Telescope, and the Magellan Inamori Kyocera Echelle Spectrograph on the Magellan Telescope. By fitting these data with synthetic spectra, we determine various stellar parameters (Teff=10850{+/-}250K, logg=2.20{+/-}0.13) and the photospheric abundances of 26 elements, including Ne, P, Cl, Ga, Pd, In, Sn, Hg, and Pb, which have not previously been published for this cluster. Abundances of intermediate-mass elements (Mg through Ga) generally scale with Fe, while the heaviest elements (Pd through Pb) have roughly solar abundances. Its low C/O ratio indicates that the star did not undergo third dredge-up and suggests that its heavy elements were made by a previous generation of stars. If so, this pattern should be present throughout the cluster, not just in this star. Stellar-evolution models suggest that the Bright Star is powered by a He-burning shell, having left the AGB during or immediately after a thermal pulse. Its mass (0.54{+/-}0.16M{sun}) implies that single stars in 47Tuc lose 0.1-0.2M{sun} on the AGB, only slightly less than they lose on the red giant branch.
- ID:
- ivo://CDS.VizieR/J/ApJ/718/L141
- Title:
- FUV diffuse emission from the LMC
- Short Name:
- J/ApJ/718/L141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first observations of diffuse radiation in the far-ultraviolet (FUV; 1000-1150{AA}) from the Large Magellanic Cloud based on observations made with the Far Ultraviolet Spectroscopic Explorer. The fraction of the total radiation in the field emitted as diffuse radiation is typically 5%-20% with a high of 45% near N70 where there are few exciting stars, indicating that much of the emission is not due to nearby stars. Much less light is scattered in the FUV than at longer wavelengths, with the stellar radiation going into heating the interstellar dust.
- ID:
- ivo://CDS.VizieR/J/MNRAS/414/3410
- Title:
- FUV excess in early-type galaxies
- Short Name:
- J/MNRAS/414/3410
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present surface photometry of a sample of 52 galaxies from the GALaxy Evolution eXplorer (GALEX) and Two-Micron All-Sky Survey (2MASS) data archives. These include 32 normal elliptical galaxies, 10 ellipticals with weak LINER or other nuclear activity and 10 star-forming ellipticals or early-type spirals. We examine the spatial distribution of the far-ultraviolet excess in these galaxies, and its correlation with dynamical and stellar population properties of the galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/140/1194
- Title:
- FUV/HI relations in nearby galaxies
- Short Name:
- J/AJ/140/1194
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We combine data from The HI Nearby Galaxy Survey and the GALEX Nearby Galaxy Survey to study the relationship between atomic hydrogen (HI) and far-ultraviolet (FUV) emission outside the optical radius (r25) in 17 spiral and 5 dwarf galaxies. In this regime, HI is likely to represent most of the interstellar medium (ISM) and FUV emission to trace recent star formation with little bias due to extinction, so that the two quantities closely trace the underlying relationship between gas and star formation rate (SFR).
- ID:
- ivo://CDS.VizieR/J/ApJ/625/156
- Title:
- FUV-NUV observations of NGC 2808
- Short Name:
- J/ApJ/625/156
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a reanalysis of far-ultraviolet (FUV) observations of the globular cluster NGC 2808 obtained with the Hubble Space Telescope. These data were first analyzed by Brown and coworkers (2001, Cat. <J/ApJ/562/368>), with an emphasis on the bright, blue horizontal-branch (HB) stars in this cluster. Here, our focus is on the population of fainter FUV sources, which include white dwarfs (WDs), blue stragglers (BSs), and cataclysmic variables (CVs).
- ID:
- ivo://CDS.VizieR/J/ApJ/765/2
- Title:
- FUV radial velocities of 59 Cyg
- Short Name:
- J/ApJ/765/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the detection of a hot subdwarf component in the Be binary system, 59 Cygni. The spectral signature is found in cross-correlation functions of photospheric model spectra with far-ultraviolet spectra obtained by the International Ultraviolet Explorer Satellite, and we used radial velocities from the cross-correlation functions to determine a double-lined spectroscopic orbit. The individual spectra of the binary components were extracted using a Doppler tomography algorithm. The flux of the system is dominated by the rapidly rotating Be star. However, the subdwarf contributes approximately 4% of the UV flux, and its spectrum bears a strong resemblance to that of the hot sdO star BD +75{deg}325. Based on the appearance of the UV spectrum and the orbital elements, we present estimates for the stellar masses, radii, and temperatures. The presence of the hot companion causes excess emission from the outer part of the Be disk facing the companion. We present a set of red spectra that show the orbital phase variations of the He I {lambda}6678 emission formed in the heated region of the disk, which probably occurs near the disk outer boundary. 59 Cygni, FY Canis Majoris, and {phi} Persei comprise the known set of Be binaries with detected hot evolved companions, which are the stripped down remains of mass transfer. Their properties demonstrate that some fraction of Be stars were spun up through angular momentum transfer by Roche lobe overflow.
- ID:
- ivo://CDS.VizieR/J/ApJS/236/36
- Title:
- Ga, Ge, As, Kr, Cd, Sn and Pb column densities
- Short Name:
- J/ApJS/236/36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an extensive analysis of the gas-phase abundances and depletion behaviors of neutron-capture elements in the interstellar medium (ISM). Column densities (or upper limits to the column densities) of Ga II, Ge II, As II, Kr I, Cd II, Sn II, and Pb II are determined for a sample of 69 sight lines with high- and/or medium-resolution archival spectra obtained with the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope. An additional 59 sight lines with column density measurements reported in the literature are included in our analysis. Parameters that characterize the depletion trends of the elements are derived according to the methodology developed by Jenkins (2009, J/ApJ/700/1299). The depletion patterns exhibited by Ga and Ge comport with expectations based on the depletion results obtained for many other elements. Arsenic exhibits much less depletion than expected, and its abundance in low-depletion sight lines may even be supersolar. We confirm a previous finding by Jenkins that the depletion of Kr increases as the overall depletion level increases from one sight line to another. Cadmium shows no such evidence of increasing depletion. We find a significant amount of scatter in the gas-phase abundances of Sn and Pb. For Sn, at least, the scatter may be evidence of real intrinsic abundance variations due to s-process enrichment combined with inefficient mixing in the ISM.
- ID:
- ivo://CDS.VizieR/J/other/RMxAA/53.439
- Title:
- Gaia stars with GALEX NUV excess
- Short Name:
- J/other/RMxAA/53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accurate parallaxes from Gaia DR1 (TGAS) are combined with GALEX visual Nuv magnitudes to produce absolute MNUV magnitudes and an ultraviolet HR diagram for a large sample of astrometric stars. A functional fit is derived of the lower envelope main sequence of the nearest 1403 stars (distance <40pc), which should be reddening-free. Using this empirical fit, 50 nearby stars are selected with significant Nuv excess. These are predominantly late K and early M dwarfs, often associated with X-ray sources, and showing other manifestations of magnetic activity. The sample may include systems with hidden white dwarfs, stars younger than the Pleiades, or, most likely, tight interacting binaries of the BY Dra-type. A separate collection of 40 stars with precise trigonometric parallaxes and Nuv-G colors bluer than 2mag is presented. It includes several known novae, white dwarfs, and binaries with hot subdwarf (sdOB) components, but most remain unexplored.
- ID:
- ivo://CDS.VizieR/J/MNRAS/415/431
- Title:
- Galaxies with wide HI profiles
- Short Name:
- J/MNRAS/415/431
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the nature of objects in a complete sample of 28 galaxies selected from the first sky area fully covered by the Arecibo Legacy Fast ALFA (ALFALFA) survey, being well detected and having HI profiles wider than 550km/s. The selection does not use brightness, morphology or any other property derived from optical or other spectral bands. We investigate the degree of isolation, the morphology and other properties gathered or derived from open data bases and show that some objects have wide HI profiles probably because they are disturbed or are interacting, or might be confused in the ALFALFA beam.
