- ID:
- ivo://CDS.VizieR/J/A+A/603/A58
- Title:
- Full spectrum of Proxima Centauri
- Short Name:
- J/A+A/603/A58
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The discovery of Proxima b, a terrestrial temperate planet, presents the opportunity of studying a potentially habitable world in optimal conditions. A key aspect to model its habitability is to understand the radiation environment of the planet in the full spectral domain. We characterize the X-rays to mid-IR radiative properties of Proxima with the goal of providing the top-of-atmosphere fluxes on the planet. We also aim at constraining the fundamental properties of the star, namely its mass, radius, effective temperature and luminosity. We employ observations from a large number of facilities and make use of different methodologies to piece together the full spectral energy distribution of Proxima. In the high-energy domain, we pay particular attention to the contribution by rotational modulation, activity cycle, and flares so that the data provided are representative of the overall radiation dose received by the atmosphere of the planet.
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- ID:
- ivo://CDS.VizieR/J/PASP/121/634
- Title:
- FUSE observations in Magellanic Clouds
- Short Name:
- J/PASP/121/634
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an atlas of stellar sight line data from the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite for 287 stars in the Magellanic Clouds, obtained from eight years of satellite operations. The intent of our project is to make this rich ensemble data set accessible to a broad community of researchers in a standardized format that will enable easy identification of subsets of these data that are appropriate for pursuing specific science programs. We present the data in a standardized manner, showing key interstellar lines on a velocity scale, optical (MCELS) and infrared (Spitzer) sight line context images, and overview plots of the spectral region containing the OVI {lambda}{lambda}1032, 1038 doublet, and the entire 905-1187{AA} spectral range observed with FUSE. Objects with multiple observations have had their data summed to directly provide the highest signal-to-noise ratio available. These data are accessible online as a High Level Science Product through the Multimission Archive at Space Telescope (MAST). In this article, we describe the data sets and processing, the atlas materials, and the MAST interface in detail, and also provide examples of how to use these materials.
- ID:
- ivo://CDS.VizieR/J/ApJ/764/25
- Title:
- FUSE spectra analysis of hot subdwarf stars
- Short Name:
- J/ApJ/764/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- When the neutral interstellar medium is exposed to extreme-ultraviolet and soft X-ray radiation, the argon atoms in it are far more susceptible to being ionized than the hydrogen atoms. We make use of this fact to determine the level of ionization in the nearby warm neutral medium. By analyzing Far-Ultraviolet Spectroscopic Explorer observations of ultraviolet spectra of 44 hot subdwarf stars a few hundred parsecs away from the Sun, we can compare column densities of Ar I to those of O I, where the relative ionization of oxygen can be used as a proxy for that of hydrogen. The measured deficiency [ArI/OI]=-0.427+/-0.11dex below the expectation for a fully neutral medium implies that the electron density n(e){approx}0.04/cm3 if n(H)=0.5/cm3. This amount of ionization is considerably larger than what we expect from primary photoionizations resulting from cosmic rays, the diffuse X-ray background, and X-ray emitting sources within the medium, along with the additional ionizations caused by energetic secondary photoelectrons, Auger electrons, and photons from helium recombinations. We favor an explanation that bursts of radiation created by previous, nearby supernova remnants that have faded by now may have elevated the ionization, and the gas has not yet recombined to a quiescent level. A different alternative is that the low-energy portion of the soft X-ray background is poorly shielded by the H I because it is frothy and has internal pockets of very hot, X-ray emitting gases.
- ID:
- ivo://CDS.VizieR/J/ApJ/647/328
- Title:
- FUSE survey of OVI in ISM
- Short Name:
- J/ApJ/647/328
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a survey of diffuse OVI emission in the interstellar medium (ISM) obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE). Spanning 5.5yr of FUSE observations, from launch through 2004 December, our data set consists of 2925 exposures along 183 sight lines, including all of those with previously published OVI detections. The data were processed using an implementation of CalFUSE version 3.1 modified to optimize the signal-to-noise ratio and velocity scale of spectra from an aperture-filling source.
- ID:
- ivo://CDS.VizieR/J/ApJS/176/59
- Title:
- FUSE survey of OVI in the disk of the Milky Way
- Short Name:
- J/ApJS/176/59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To probe the distribution and physical characteristics of interstellar gas at temperatures T~3x10^5^K in the disk of the Milky Way, we have used the Far Ultraviolet Spectroscopic Explorer (FUSE) to observe absorption lines of OVI{lambda}1032 toward 148 early-type stars situated at distances >1kpc. After subtracting off a mild excess of OVI arising from the Local Bubble, combining our new results with earlier surveys of OVI, and eliminating stars that show conspicuous localized X-ray emission, we find an average OVI midplane density n_0_=1.3x10^-8^cm^-3^. The density decreases away from the plane of the Galaxy in a way that is consistent with an exponential scale height of 3.2kpc at negative latitudes or 4.6kpc at positive latitudes.
- ID:
- ivo://CDS.VizieR/J/ApJ/647/312
- Title:
- FUSE survey of OVI in the Milky Way
- Short Name:
- J/ApJ/647/312
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a survey of OVI {lambda}1032 emission in the Milky Way using data from the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. The observations span the period from launch in 1999 to 2003 July. Our survey contains 112 sight lines, 23 of which show measurable OVI {lambda}1032 emission. The OVI {lambda}1032 emission feature was detected at all latitudes and exhibits intensities of 1900-8600photons/s/cm^2^/sr. Combined with values from the literature, these emission measurements are consistent with the picture derived from recent OVI absorption surveys: high-latitude sight lines probe OVI-emitting gas in a clumpy, thick disk or halo, while low-latitude sight lines sample mixing layers and interfaces in the thin disk of the Galaxy.
- 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.
- 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.
