Interstellar Matter Near the Pleiades. V. Observations of Na
                    <scp>i</scp>
                    toward 36 Stars

White, R. E.; Allen, Christopher; Forrester, W. B.; Gonnella, A.; Young, Kathryn L.

doi:10.1086/318950

Cited by 17 publications

(19 citation statements)

References 27 publications

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“…Gordon & Arny (1984). Two-digit labels show stars observed in this work, identified as in Table 1, three-digit labels show stars observed by White at al. (2001); the three digits are the last digits of the HD designator of the star.…”

Section: Kinematical Picture Of the Interstellar Gas In The Volume Obsupporting

confidence: 55%

Kinematical Structure of the Local Interstellar Medium: The Galactic Anticenter Hemisphere

Genova

Beckman

2003

ASTROPHYS J SUPPL S

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A survey of interstellar Na i D1 and D2 absorption features in the spectra of 104 early-type stars in the second and third Galactic quadrants reveals the large-scale kinematics of the interstellar gas within the Galactic anticenter hemisphere at distances from the Sun between $70 and $250 pc. Employing a technique that uses both the radial velocities and column densities of the Na i absorptions produced by the intervening gas we have identified the velocity vectors and determined the spatial distribution of eight interstellar clouds in the volume explored. The average internal H i + H 2 densities of the clouds range between 0.03 and 1.7 cm À3 , and their masses between 80 and 10 4 M , although uncertainties in the sizes of the clouds, their possible extension beyond the region explored, and the presence of denser gas embedded in the larger clouds imply that these will tend to be lower limits. We have clearly identified clumps of denser gas immersed in the lowdensity gas in one of the clouds; these clumps show internal H i + H 2 densities of order 50 cm À3 . Although we are not able to detect any interstellar Na i within 70 pc, the sizes of some of the clouds imply that their near edges are within that range of distances from the Sun.With respect to the local standard of rest the clouds move with velocities between 19 and 54 km s À1 . Their velocity vectors do not support the view of a local interstellar medium uniquely dominated by expansion from centers in the Scorpio-Centaurus OB association; our results suggest that this expansion is present in the Galactic center hemisphere but in the Galactic anticenter hemisphere is restricted to the immediate neighborhood of the Sun.

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Section: Kinematical Picture Of the Interstellar Gas In The Volume Obsupporting

confidence: 55%

Kinematical Structure of the Local Interstellar Medium: The Galactic Anticenter Hemisphere

Genova

Beckman

2003

ASTROPHYS J SUPPL S

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“…UT 3−7: The complex UT 3−7 at l = 163 to 168 • , b = −24 to −26.5 • is very likely closer than 100 pc, because all stars observed by White et al (2001) and more distant than about 90−100 pc have prominent NaI lines at a heliocentric velocity of 15 and 17 km s −1 , (or 6.5−8.5 km s −1 LSR), similar to the velocity of the molecular species. From the White et al targets, and our additional targets, the complex should be located between 75 and 100 pc.…”

Section: Molecular Cloudsmentioning

confidence: 99%

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

Lallement

Welsh

Vergely

et al. 2003

A&A

367

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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“…Finally, the scattering geometry is constrained by a wealth of observations. Interstellar polarization and reddening (e.g., Breger 1986Breger , 1987, atomic and molecular line absorption (Federman 1982;Bohlin et al 1983;White 1984;White et al 2001), radio line emission (Gordon & Arny 1984;Federman & Wilson 1984;Bally & White 1986), and far-infrared (FIR) thermal emission (Castelaz, Sellgren, & Werner 1987;White & Bally 1993) indicate a low level of interstellar matter across most of the cluster but more on the western side, perhaps with some optically thick dust southwest of the star 23 Tau (Merope). Enough material is probably in front of the major stars to dominate the scattered light budget for forward-scattering grains, but some of the densest gas and dust may lie behind or among the stars on the west side of the cluster.…”

Section: Introductionmentioning

confidence: 99%

The Pleiades Reflection Nebula. I. Ultraviolet, Optical, and Far‐Infrared Imaging Photometry

Gibson

Nordsieck²

2003

ApJ

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We present new wide-field optical and ultraviolet images of the Pleiades reflection nebula that allow a more thorough evaluation of the dust scattering than any prior data set. Vacuum-UV images were taken at 1650 and 2200 Å during the first flight of the Wide-Field Imaging Survey Polarimeter (WISP), a sounding rocketborne telescope. WISP captured the brighter parts of the nebula at both wavelengths, with 3 sensitivities of 22.5 and 23.4 UV mag arcsec À2 , respectively. The 5=0 Â 1=7 WISP field was also mapped at 4400 Å with a mosaic of 40 Burrell Schmidt CCD frames using a broadband B J filter. The Schmidt mosaic shows extensive and intricate nebulosity down to a 5 sensitivity limit of 27.6 B mag arcsec À2 , including features undetected by photographic surveys. We explore the intensity and color behavior of the nebula in our UV and optical images and far-infrared IRAS data. We find that the photometric structure near bright stars is more complex than previous studies have implied, but general trends are still apparent. The color gradients around the stars are caused by phase function effects rather than internal reddening. The greater concentration of scattered light versus thermal emission indicates that most of the observed scattering is from foreground dust. A somewhat greater concentration of UV versus optical light suggests grain scattering is more forward-directed at shorter wavelengths. The UV nebula is much fainter than expected from the stellar photometry and interstellar reddening. Explaining this UV faintness requires either more reddening than is measured or significant alterations to current dust property estimates.

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Interstellar Matter Near the Pleiades. V. Observations of Na i toward 36 Stars

Cited by 17 publications

References 27 publications

Kinematical Structure of the Local Interstellar Medium: The Galactic Anticenter Hemisphere

Kinematical Structure of the Local Interstellar Medium: The Galactic Anticenter Hemisphere

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

The Pleiades Reflection Nebula. I. Ultraviolet, Optical, and Far‐Infrared Imaging Photometry

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