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Edelstein, Jerry; Bowyer, Stuart; Korpela, Eric; Lampton, M.; Trapero, J.; Gómez, José F.; Morales, Carmen; Orozco, Verónica

doi:10.1023/a:1011621626714

Cited by 14 publications

(11 citation statements)

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“…Additionally, observations of the diffuse extreme ultraviolet (EUV) sky background spectral emission using both the CHIPS (Hurwitz et al 2005) and EURD (Edelstein et al 2001) satellites are also in contradiction with the predictions of the NEI model. We also note that strong Si III (1206 Å) interstellar absorption has been reported for several sight-lines towards nearby stars (Holberg et al 1999;Nehme et al 2008).…”

Section: 1mentioning

confidence: 96%

The trouble with the Local Bubble

Welsh

Shelton

2009

Astrophys Space Sci

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The model of a Local Hot Bubble has been widely accepted as providing a framework that can explain the ubiquitous presence of the soft X-ray background diffuse emission. We summarize the current knowledge on this local interstellar region, paying particular reference to observations that sample emission from the presumed local million degree K hot plasma. However, we have listed numerous observations that are seemingly in conflict with the concept of a hot Local Bubble. In particular, the discovery of solar wind charge exchange that can generate an appreciable soft X-ray background signal within the heliosphere, has led to a reassessment of the generally accepted model that requires a hot local plasma.In order to explain the majority of observations of the local plasma, we forward two new speculative models that describe the physical state of the local interstellar gas. One possible scenario is similar to the present widely accepted model of the Local Hot Bubble, except that it accounts for only 50% of the soft X-ray emission currently detected in the galactic plane, has a lower thermal pressure than previously thought, and its hot plasma is not as hot as previously believed. Although such a model can solve several difficulties with the traditional hot Local Bubble model, a heating mechanism for the dimmer and cooler gas remains to be found. The second possible explanation is that of the 'Hot Top' model, in which the Local Cavity is an old su-B.Y. Welsh ( ) Space Sciences Laboratory, University of California, 7 Gauss Way, Berkeley, CA 94720, USA e-mail: bwelsh@ssl.berkeley.edu R.L. Shelton Department of Physics and Astronomy, University of Georgia, Athens, GA 30602, USA pernova remnant in which no (or very little) million degree local plasma is presently required. Instead, the cavity is now thought to be filled with partially ionized cloudlets of temperature ∼ 7000 K that are surrounded by lower density envelopes of photo-ionized gas of temperature ∼ 20,000 K. Although this new scenario provides a natural explanation for many of the observations that were in conflict with the Local Hot Bubble model, we cannot (as yet) provide a satisfactory explanation or the emission levels observed in the B and Be ultra-soft X-ray bands.

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Section: 1mentioning

confidence: 96%

The trouble with the Local Bubble

Welsh

Shelton

2009

Astrophys Space Sci

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“…In Figure 16, we compare these predictions with 40 yr of observational constraints from rocket-borne detectors (Lillie & Witt 1976;Anderson et al 1979;Jakobsen et al 1984;Tennyson et al 1988), Apollo 17 (Henry et al 1978), Apollo-Soyuz (Paresce et al 1980), Solrad-11 (Weller 1983), Voyager 2 (Holberg 1986) shuttle-borne spectrometers (Murthy et al 1990;Martin et al 1991), Dynamics Explorer-1 (Witt & Petersohn 1994), DUVE (Korpela et al 1998), EURD/Minisat (Edelstein et al 2001), and Hubble Space Telescope/Las Campanas (Bernstein et al 2002). Filled symbols indicate mostly spectroscopic data, whereas open symbols indicate mostly photometric ones.…”

Section: Extragalactic Far-ultraviolet Radiation?mentioning

confidence: 99%

The Mystery of the Cosmic Diffuse Ultraviolet Background Radiation

Henry

Murthy

Overduin

et al. 2014

ApJ

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The diffuse cosmic background radiation in the Galaxy Evolution Explorer far-ultraviolet (FUV, 1300-1700 Å) is deduced to originate only partially in the dust-scattered radiation of FUV-emitting stars: the source of a substantial fraction of the FUV background radiation remains a mystery. The radiation is remarkably uniform at both far northern and far southern Galactic latitudes and increases toward lower Galactic latitudes at all Galactic longitudes. We examine speculation that this might be due to interaction of the dark matter with the nuclei of the interstellar medium, but we are unable to point to a plausible mechanism for an effective interaction. We also explore the possibility that we are seeing radiation from bright FUV-emitting stars scattering from a "second population" of interstellar grains-grains that are small compared with FUV wavelengths. Such grains are known to exist, and they scatter with very high albedo, with an isotropic scattering pattern. However, comparison with the observed distribution (deduced from their 100 μm emission) of grains at high Galactic latitudes shows no correlation between the grains' location and the observed FUV emission. Our modeling of the FUV scattering by small grains also shows that there must be remarkably few such "smaller" grains at high Galactic latitudes, both north and south; this likely means simply that there is very little interstellar dust of any kind at the Galactic poles, in agreement with Perry and Johnston. We also review our limited knowledge of the cosmic diffuse background at ultraviolet wavelengths shortward of Lyα-it could be that our "second component" of the diffuse FUV background persists shortward of the Lyman limit and is the cause of the reionization of the universe.

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“…CHIANTI data have been applied also to studies of nonstellar objects, such as supernova remnants (Smith & Cox 2001;Sankrit et al 2003;Velazquez et al 2003Velazquez et al , 2004, interstellar medium (Arthur 2001;Edelstein et al 2001;Hurwitz et al 2005), Herbig-Haro objects ( Raga et al 2002), the Io plasma torus ( Herbert et al 2001;Feldman et al 2001Feldman et al , 2004, the shock-cloud interaction in the Cygnus Loop (Danforth et al 2001), and galaxies (Dixon et al 2001;Swartz et al 2002;Matsumoto et al 2004;Lee & Hwang 2004).…”

Section: Introductionmentioning

confidence: 99%

CHIANTI—An Atomic Database for Emission Lines. VII. New Data for X‐Rays and Other Improvements

Landi

Zanna²,

Young

et al. 2006

ASTROPHYS J SUPPL S

427

229

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The CHIANTI atomic database contains atomic energy levels, wavelengths, radiative transition probabilities, and collisional excitation data for a large number of ions of astrophysical interest. CHIANTI also includes a suite of IDL routines to calculate synthetic spectra and carry out plasma diagnostics. Version 5 has been released, which includes several new features, as well as new data for many ions. The new features in CHIANTI are as follows: the inclusion of ionization and recombination rates to individual excited levels as a means to populate atomic levels; data for K and K emission from Fe ii to Fe xxiv; new data for high-energy configurations in Fe xvii to Fe xxiii; and a complete reassessment of level energies and line identifications in the X-ray range, multitemperature particle distributions, and photoexcitation from any user-defined radiation field. New data for ions already in the database, as well as data for ions not present in earlier versions of the database, are also included. Version 5 of CHIANTI represents a major improvement in the calculation of line emissivities and synthetic spectra in the X-ray range and expands and improves theoretical spectra calculations in all other wavelength ranges.

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Cited by 14 publications

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The trouble with the Local Bubble

The trouble with the Local Bubble

The Mystery of the Cosmic Diffuse Ultraviolet Background Radiation

CHIANTI—An Atomic Database for Emission Lines. VII. New Data for X‐Rays and Other Improvements

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