NaI and HI 3-D density distribution in the solar neighbourhood

Vergely, Jean‐Luc; Ferrero, R. Freire; Siebert, A.; Valette, Bernard

doi:10.1051/0004-6361:20010006

Cited by 68 publications

(101 citation statements)

References 18 publications

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“…Using these data, together with NaI absorption measurements towards a further ∼240 nearby targets published in the literature (for many of them, in the directions of molecular clouds), and the ∼450 linesof-sight already presented by , we show 3D absorption maps of the local distribution of neutral gas towards 1005 sight-lines with Hipparcos distances as viewed from a variety of different galactic projections. The data are synthesized by means of two complementary methods, (i) by mapping of iso-equivalent width contours, and (ii) by density distribution calculation from the inversion of column-densities, a method devised by Vergely et al (2001). Our present data confirms the view that the local cavity is deficient in cold and neutral interstellar gas.…”

supporting

confidence: 68%

3D mapping of the dense interstellar gas around the Local Bubble

Lallement

Welsh

Vergely

et al. 2003

A&A

363

463

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Abstract. We present intermediate results from a long-term program of mapping the neutral absorption characteristics of the local interstellar medium, motivated by the availability of accurate and consistent parallaxes from the Hipparcos satellite. Equivalent widths of the interstellar NaI D-line doublet at 5890 Å are presented for the lines-of-sight towards some 311 new target stars lying within ∼350 pc of the Sun. Using these data, together with NaI absorption measurements towards a further ∼240 nearby targets published in the literature (for many of them, in the directions of molecular clouds), and the ∼450 linesof-sight already presented by , we show 3D absorption maps of the local distribution of neutral gas towards 1005 sight-lines with Hipparcos distances as viewed from a variety of different galactic projections. The data are synthesized by means of two complementary methods, (i) by mapping of iso-equivalent width contours, and (ii) by density distribution calculation from the inversion of column-densities, a method devised by Vergely et al. (2001). Our present data confirms the view that the local cavity is deficient in cold and neutral interstellar gas. The closest dense and cold gas "wall", in the first quadrant, is at ∼55-60 pc. There are a few isolated clouds at closer distance, if the detected absorption is not produced by circumstellar material. The maps reveal narrow or wide "interstellar tunnels" which connect the Local Bubble to surrounding cavities, as predicted by the model of Cox & Smith (1974). In particular, one of these tunnels, defined by stars at 300 to 600 pc from the Sun showing negligible sodium absorption, connects the well known CMa void , which is part of the Local Bubble, with the supershell GSH 238+00+09 (Heiles 1998). High latitude lines-of-sight with the smallest absorption are found in two "chimneys", whose directions are perpendicular to the Gould belt plane. The maps show that the Local Bubble is "squeezed" by surrounding shells in a complicated pattern and suggest that its pressure is smaller than in those expanding regions. We discuss the locations of several HI and molecular clouds. Using comparisons between NaI and HI or CO velocities, in some cases we are able to improve the constraints on their distances. According to the velocity criteria, MBM 33−37, MBM 16−18, UT 3−7, and MBM 54−55 are closer than ∼100 pc, and MBM 40 is closer than 80 pc. Dense HI clouds are seen at less than 90 pc and 85 pc in the directions of the MBM 12 and MBM 41−43 clouds respectively, but the molecular clouds themselves may be far beyond. The above closest molecular clouds are located at the neutral boundary of the Bubble. Only one translucent cloud, G192−67, is clearly embedded within the LB and well isolated. These maps of the distribution of local neutral interstellar NaI gas are also briefly compared with the distribution of both interstellar dust and neutral HI gas within 300 pc.

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supporting

confidence: 68%

3D mapping of the dense interstellar gas around the Local Bubble

Lallement

Welsh

Vergely

et al. 2003

A&A

363

463

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“…The first computed tomography of the local ISM from Vergely et al (2001) used neutral sodium absorption data combined with Hipparcos stellar parallaxes (Perryman et al 1997) and a tomographic method based on the work of Tarantola & Valette (1982a), specifically applied for the first time to extinction by the ISM by Chen et al (1998). This type of tomography is a new manner to represent the ISM, considering it as a continuous medium without a priori cloud discretization and considering the clouds and the voids as fluctuations around a median density, the "prior" value.…”

Section: Introductionmentioning

confidence: 99%

“…This type of tomography is a new manner to represent the ISM, considering it as a continuous medium without a priori cloud discretization and considering the clouds and the voids as fluctuations around a median density, the "prior" value. Lallement et al (2003) presented additional sodium observations especially dedicated to the Local Bubble boundary determination, recorded during several observing programs, and made use of about 1000 carefully screened data for a column density mapping and a tomography based on the same algorithm as in Vergely et al (2001). An updated study using about 1700 targets as well as the first tomography using ionized calcium are presented in the recent study by Welsh et al (2010).…”

Section: Introductionmentioning

confidence: 99%

Spatial distribution of interstellar dust in the Sun's vicinity

Vergely¹,

Valette

Lallement

et al. 2010

A&A

Self Cite

107

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Aims. 3D tomography of the interstellar dust and gas may be useful in many respects, from the physical and chemical evolution of the interstellar medium itself to foreground decontamination of the cosmic microwave background, or various studies of the environments of specific objects. However, while spectral data cubes of the galactic emission become increasingly precise, the information on the distance to the emitting regions has not progressed as well and relies essentially on the galactic rotation curve. Our goal here is to bring more precise information on the distance to nearby interstellar dust and gas clouds within 250 pc. Methods. We apply the best available calibration methods to a carefully screened set of stellar Strömgren photometry data for targets possessing a Hipparcos parallax and spectral type classification. We combine the derived interstellar extinctions and the parallax distances for about 6000 stars to build a 3D tomography of the local dust. We use an inversion method based on a regularized Bayesian approach and a least squares criterion, optimized for this specific data set. We apply the same inversion technique to a totally independent set of neutral sodium absorption data available for about 1700 target stars. Results. We obtain 3D maps of the opacity and the distance to the main dust-bearing clouds within 250 pc and identify in those maps well-known dark clouds and high galactic more diffuse entities. We calculate the integrated extinction between the Sun and the cube boundary and compare this with the total galactic extinction derived from infrared 2D maps. The two quantities reach similar values at high latitudes, as expected if the local dust content is satisfyingly reproduced and the dust is closer than 250 pc. Those maps show a larger high latitude dust opacity in the North compared to the South, reinforcing earlier evidences. Interestingly the gas maps do not show the same asymmetry, suggesting a polar asymmetry of the dust to gas ratio at small distances. We compare the opacity distribution with the 3D distribution of interstellar neutral sodium resulting from the inversion of sodium columns. We discuss the similarities and discrepancies and the influence of data set limitations. Finally we discuss the potential improvements of those 3D maps.

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“…Therefore this lowcolumn density uncertainty is not important considering the M7 and negligible for the intended population synthesis with neutron stars (NSs) at usually larger distances. Vergely et al (2001) could not always find a correlation of the Nai density with the H i density. They concluded that the correlation is rather weak due to non-constant population ratios for interstellar medium species, thus different abundances.…”

Section: The Inhomogeneously Distributed Ismmentioning

confidence: 79%

“…Breitschwerdt 1998). The most detailed view is provided by the study of Lallement et al (2003), who measured Na i absorption towards 1005 sightlines with Hipparcos distances up to 350 pc from the Sun; for more details on the measurements and the applied density inversion method see Lallement et al (2003), the precursor paper Sfeir et al (1999), andVergely et al (2001). Nai is regarded as good tracer of the total amount of the neutral interstellar gas and the sodium column density is thought to be convertable into a hydrogen column density (e.g.…”

Section: The Inhomogeneously Distributed Ismmentioning

confidence: 99%

The Magnificent Seven in the dusty prairie

Posselt

Попов

Haberl

et al. 2007

Isolated Neutron Stars: From the Surface to the Interior

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The Magnificent Seven have all been discovered by their exceptional soft X-ray spectra and high ratios of X-ray to optical flux. They all are considered to be nearby sources. Searching for similar objects with larger distances, one expects larger interstellar absorption resulting in harder X-ray counterparts. Current interstellar absorption treatment depends on chosen abundances and scattering cross-sections of the elements as well as on the 3D distribution of the interstellar medium. After a discussion of these factors we use the comprehensive 3D measurements of the Local Bubble by Lallement et al. (2003) to construct two simple models of the 3D distribution of the hydrogen column density. We test these models by using a set of soft X-ray sources with known distances. Finally, we discuss possible applications for distance estimations and population synthesis studies.

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NaI and HI 3-D density distribution in the solar neighbourhood

Cited by 68 publications

References 18 publications

3D mapping of the dense interstellar gas around the Local Bubble

3D mapping of the dense interstellar gas around the Local Bubble

Spatial distribution of interstellar dust in the Sun's vicinity

The Magnificent Seven in the dusty prairie

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