High-Velocity Gas in GHRS Spectra of Three OB Stars

Trapero, J.; Welty, D. E.; Hobbs, L. M.; Lauroesch, J. T.; Morton, Donald C.; Spitzer, Lyman; York, D. G.

doi:10.1086/177690

Cited by 25 publications

(35 citation statements)

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“…For most of the lines, the equivalent widths correspond to the strong low-velocity absorption seen at 0 km km s~1 ; absorps~1 Trapero et al 1996). Lines observed at high resolution km s~1) are (FWHM [ 4 4 In this study, we will use heliocentric velocities ; the zero point for velocities with respect to the local standard of rest is at km Cowie et al 1979 andJenkins et al 1986.…”

Section: Uv Spectramentioning

confidence: 99%

“…In the HV gas toward f Ori, for example, Welty et al (1999d) C II), however, is less than half the solar value, so that Al appears to be slightly depleted 10 We have combined our G160M spectra of the S III j1190 line with similar data from the HST archive to obtain a smaller upper limit on N(S III) in the HV gas than the one given by Trapero et al (1996). even for log [N(H II)] D 17.7 cm~2.…”

Section: N(s Ii) ] N(s Iii)mentioning

confidence: 99%

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The Diffuse Interstellar Clouds toward 23 Orionis

Welty

Hobbs

Lauroesch

et al. 1999

ASTROPHYS J SUPPL S

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181

249

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Spectra obtained with the Hubble Space T elescope Goddard High Resolution Spectrograph are combined with high-resolution optical spectra and UV spectra from Copernicus to study the abundances and physical conditions in the di †use interstellar clouds seen along the line of sight to the star 23 Ori. Multiple absorption components are present for each of several distinct types of gas, which are characterized by di †erent relative abundance and depletion patterns and physical conditions. Strong low-velocity (SLV) absorption, due to cool, moderately dense neutral gas and representing about 92% of the total N(H I), is seen for various neutral and singly ionized species at ]20 km s~1 km s~1. Most typically severely depleted species are less depleted by factors of 2È4, com-

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Section: Uv Spectramentioning

confidence: 99%

Section: N(s Ii) ] N(s Iii)mentioning

confidence: 99%

The Diffuse Interstellar Clouds toward 23 Orionis

Welty

Hobbs

Lauroesch

et al. 1999

ASTROPHYS J SUPPL S

Self Cite

181

249

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“…It is a large, bright, nearby object (d $ 130 pc; Stello & Nissen 2001), allowing dust to be observed for a variety of scattering angles. Photometric measurements are unlikely to be contaminated by line emission, since absorption studies of the region show only low-ionization species (White 1984;Trapero et al 1996), the H emission is very weak (S. Tufte 1993, private communication), and neither fluorescent emission nor extended red emission is found (Rush & Witt 1975;Witt & Boroson 1990). Finally, the scattering geometry is constrained by a wealth of observations.…”

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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“…We have already discussed how the variation of the N(Na )/N(Ca ) cloud column-density ratio can be used as an interstellar gas diagnostic in Sect. 4.3, and the column-density comparison method for UV absorption lines has also been used successfully by Jenkins et al (1984) and Trapero et al (1996) for high-velocity gas clouds in the ISM.…”

Section: The Far-uv Absorption Spectramentioning

confidence: 99%

Intermediate-velocity gas observed towards the Shajn 147 SNR

Sallmen¹,

Welsh

2004

A&A

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Abstract. We present high-resolution spectra (R ∼ 3 km s −1 ) of the interstellar Na  and Ca  interstellar absorption lines observed towards 3 early-type stars with distances of 360 to 1380 pc along the line-of-sight towards the 800 pc distant Shajn 147 (S147) Supernova Remnant (SNR). These data are supplemented with far-UV (912-1180 Å) aborption spectra of HD 36665 and HD 37318 recorded with the NASA Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. The observations reveal intermediate-velocity (IV) absorption features at V helio = +92 km s −1 towards HD 37318 and at V helio = −65 and −52 km stowards HD 36665, in addition to several other gas cloud components with lower velocity. These IV components can be associated with the expansion of the SNR that has disrupted the surrounding interstellar gas. The IV component at V = +92 km s −1 seen towards HD 37318 was detected only in the far-UV lines of Fe  and N , suggesting that it is composed mainly of warm and ionized gas. The two IV components observed towards HD 36665 were detected in Na , Ca , N , N , O  and Fe , indicating that it is composed of both neutral and ionized gas shells. Highly ionized gas was detected in the O λ 1032 Å absorption line at V ∼ +40 km s −1 towards both stars. This hot and highly ionized gas component is characterized by a columnn density ratio of N(C )/N(O ) < 0.27, which is consistent with that predicted by current models of evolved SNRs. However, we cannot preclude its origin in the interstellar medium in line-of-sight to S147. Column-density ratios of [Mg/Fe] [Na/Ca] have been derived for the IV gas components detected towards S147. Similar ratios have also been derived for fast-moving gas observed towards two other SNRs in order to gain some insight into the behavior of element abundances in the disturbed interstellar gas associated with these regions. In all cases except for Na and Ca, these elements appear to be present with near-solar abundance ratios.

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High-Velocity Gas in GHRS Spectra of Three OB Stars

Cited by 25 publications

References 0 publications

The Diffuse Interstellar Clouds toward 23 Orionis

The Diffuse Interstellar Clouds toward 23 Orionis

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

Intermediate-velocity gas observed towards the Shajn 147 SNR

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