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111. Fe XII UV line intensity ratios
ID:
ivo://CDS.VizieR/J/A+A/370/1071
Title:
Fe XII UV line intensity ratios
Short Name:
J/A+A/370/1071
Date:
21 Oct 2021
Publisher:
CDS
Description:
A new set of radiative and electron collisional data for Fe XII was presented in two earlier papers. In the present work, we derive level populations and theoretical line intensities for a range of plasma densities and temperatures. Observations of Fe XII lines obtained with the Solar EUV Rocket Telescope and Spectrograph are analysed both as a check on the quality of the new atomic data and to determine the electron density in active regions and the quiet Sun. The discrepancy between the electron density values determined from Fe XII line intensity ratios and those obtained from other ions is investigated.
112. Final Merged Log of IUE Observations
ID:
ivo://CDS.VizieR/VI/110
Title:
Final Merged Log of IUE Observations
Short Name:
VI/110
Date:
21 Oct 2021
Publisher:
CDS
Description:
The log contains a summary of all IUE Newly Extracted Spectra (INES), which resulted from a post-processing effort at Vilspa. It was constructed by using verified data from the IUE Final Archive Master Catalogue. The observations cover the whole life of the satellite, from March 1978 to September 1996.
113. Fluctuations of UV background from GALEX
ID:
ivo://CDS.VizieR/J/A+A/631/A59
Title:
Fluctuations of UV background from GALEX
Short Name:
J/A+A/631/A59
Date:
21 Oct 2021
Publisher:
CDS
Description:
The all sky survey run by the Galaxy Evolution Explorer (GALEX AIS) mapped about 85 % of the Galaxy at ultraviolet (UV) wavelengths and detected the diffuse UV background produced by the scattering of the radiation from OBA stars by interstellar dust grains. Against this background, diffuse weak structures are detected as well as the UV counterparts to nebulae and molecular clouds. To make full profit of the survey, unsupervised and semi-supervised procedures need to be implemented. The main objective of this work is to implement and analyze the results of the method developed by us for the blind detection of ISM features in the GALEX AIS. Most ISM features are detected at very low signal levels (dark filaments, globules) against the already faint UV background. We have defined an index the UV background fluctuations index (or UBF index) to identify areas of the sky where these fluctuations are detected. The algorithm is applied to the images obtained in the FUV (1344-1786{AA}) band since this is less polluted by stellar sources, facilitating the automated detection. The UBF index is shown to be sensitive to the main star forming regions within the Gould's Belt, as well as to some prominent loops like Loop I or the Eridanus and Monogem areas. The catalogue with the UBF index values is made available on-line to the community.
114. Flux conversion factors for the Swift/UVOT filters
ID:
ivo://CDS.VizieR/J/AJ/152/102
Title:
Flux conversion factors for the Swift/UVOT filters
Short Name:
J/AJ/152/102
Date:
21 Oct 2021
Publisher:
CDS
Description:
We discuss the transformation of observed photometry into flux for the creation of spectral energy distributions (SED) and the computation of bolometric luminosities. We do this in the context of supernova studies, particularly as observed with the Swift spacecraft, but the concepts and techniques should be applicable to many other types of sources and wavelength regimes. Traditional methods of converting observed magnitudes to flux densities are not very accurate when applied to UV photometry. Common methods for extinction and the integration of pseudo-bolometric fluxes can also lead to inaccurate results. The sources of inaccuracy, though, also apply to other wavelengths. Because of the complicated nature of translating broadband photometry into monochromatic flux densities, comparison between observed photometry and a spectroscopic model is best done by forward modeling the spectrum into the count rates or magnitudes of the observations. We recommend that integrated flux measurements be made using a spectrum or SED which is consistent with the multi-band photometry rather than converting individual photometric measurements to flux densities, linearly interpolating between the points, and integrating. We also highlight some specific areas where the UV flux can be mischaracterized.
115. Full spectrum of Proxima Centauri
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.
116. FUSE observations in Magellanic Clouds
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.
117. FUSE spectra analysis of hot subdwarf stars
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.
118. FUSE survey of OVI in ISM
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.
119. FUSE survey of OVI in the disk of the Milky Way
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.
120. FUSE survey of OVI in the Milky Way
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.