An ultraviolet extinction study of the rho Ophiuchi dark cloud

Wu, Cc; Gilra, D. P.; Vanduinen, Rj

doi:10.1086/158329

Cited by 10 publications

(5 citation statements)

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“…(1982)). Wu et al (1980) showed that the extinction curves obtained from ANS observations closely match those based on OAO-2 measurements. It seems evident that the location of the five ANS photometric channels is optimal for the definition of meaningful extinction curves which closely reproduce those derived from observations with a significantly higher spectral resolution.…”

supporting

confidence: 57%

The interstellar 217 nm band: a third catalogue of equivalent widths

Friedemann

Röder

1987

Astron Nachr

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Using the data obtained with the ultraviolet photometer in the Astronomical Netherlands Satellite the equivalent widths of the interstellar 21 7 nm band as well as other parameters characterizing the behaviour of the continuous interstellar extinction in the wavelength region of the band have been derived for 790 0, B stars with colour excesses E(B -V) 2 0.4 mag. Die mit dem im Astronomical Netherlands Satellite instalherten Ultraviolett-Photometer gemessenen Helligkeiten wurden benutzt, um fur 790 0, B Sterne mit Farbexzessen E(B -V) 2 0.4 mag die Aquivalentbreiten der interstellaren 217 nm-Bande sowie weitere den Verlauf der interstellaren Extinktion im Bereich dieser Bande beschreibende Parameter abzuleiten.

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supporting

confidence: 57%

The interstellar 217 nm band: a third catalogue of equivalent widths

Friedemann

Röder

1987

Astron Nachr

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“…These sight lines also feature low UV extinction and, in the case of NGC 6530, weaker than average 2175 8 bumps. Large R(V ) are well known in the Ophiuchus region (Chini & Krügel 1983), and the UV extinction has been examined by Wu et al (1980). UV extinction toward NGC 6530 was studied by Torres (1987).…”

Section: Spatial Trendsmentioning

confidence: 99%

An Analysis of the Shapes of Interstellar Extinction Curves. V. The IR‐through‐UV Curve Morphology

Fitzpatrick

Massa

2007

ApJ

705

844

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We study the IR-through-UV wavelength dependence of 328 Galactic interstellar extinction curves affecting normal, near-main-sequence B and late O stars. We derive the curves using a new technique that employs stellar atmosphere models in lieu of unreddened ''standard'' stars. Under ideal conditions, this technique is capable of virtually eliminating spectral mismatch errors in the curves. In general, it lends itself to a quantitative assessment of the errors and enables a rigorous testing of the significance of relationships between various curve parameters, regardless of whether their uncertainties are correlated. Analysis of the curves gives the following results:1. In accord with our previous findings, the central position of the 2175 8 extinction bump is mildly variable, its width is highly variable, and the two variations are unrelated.2. Strong correlations are found among some extinction properties within the UV region, and within the IR region.3. With the exception of a few curves with extreme (i.e., large) values of R(V ), the UVand IR portions of Galactic extinction curves are not correlated with each other.4. The large sight lineYtoYsight line variation seen in our sample implies that any average Galactic extinction curve will always reflect the biases of its parent sample.5. The use of an average curve to deredden a spectral energy distribution (SED) will result in significant errors, and a realistic error budget for the dereddened SED must include the observed variance of Galactic curves.While the observed large sight lineYtoYsight line variations, and the lack of correlation among the various features of the curves, make it difficult to meaningfully characterize average extinction properties, they demonstrate that extinction curves respond sensitively to local conditions. Thus, each curve contains potentially unique information about the grains along its sight line.

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“…In the ultraviolet the extinction curve is strongly peaked at 2200 Â (Stecher 1969;Bless and Savage 1972). Although there may be significant variation in the slope of the far uv extinction curve for different regions of the sky, the excess extinction at 2200 Â with respect to the line joining the 1800 Á and 2500 Â points is relatively constant at approximately 2 magnitudes per unit E(B -V) (Wu, Gilra, and van Duinen 1980). If the intrinsic spectrum has a smooth energy distribution, a reddening even as low as E(B-V) = 0.05 will cause a readily apparent flux deficiency of 0™1 at 2200 Á.…”

Section: The Ultraviolet Colors Of Cyg X-l a Interstellar Reddening A...mentioning

confidence: 99%

ANS spectrophotometry - The bright X-ray binaries Hercules X-1 /HZ Herculis/ and Cygnus X-1 /HDE 226868/

Wu¹,

Holm²,

Eaton³

et al. 1982

PASP

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We have obtained complete ultraviolet light curves for HZ Her immediately after a well-defined X-ray turn on in 1975. The features of this light curve correspond well with features seen in the optical. The absolute level of emission at maximum light at 1550 Á agrees well with the calculations of the X-ray reflection effect of Milgrom and Salpeter. We find that at 1550 Á roughly 20% of the light at maximum comes from the accretion disk. Similar observations of Cyg X-l allow us to determine the degree of reddening, equivalent to E(B -V) = 0.95 ± 0.07, from the strength of the 2200 Á interstellar absorption feature. The distance inferred from this amount of reddening requires the optical star to be luminous and, therefore, massive. Observations obtained during the May 1975 X-ray transition show ultraviolet excess when compared to the data obtained six months later. We find that these changes are unlikely to be caused by reflection effect or by emission of the accretion disk but, most likely, reflect intrinsic changes in the B0 supergiant star.

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An ultraviolet extinction study of the rho Ophiuchi dark cloud

Cited by 10 publications

References 0 publications

The interstellar 217 nm band: a third catalogue of equivalent widths

The interstellar 217 nm band: a third catalogue of equivalent widths

An Analysis of the Shapes of Interstellar Extinction Curves. V. The IR‐through‐UV Curve Morphology

ANS spectrophotometry - The bright X-ray binaries Hercules X-1 /HZ Herculis/ and Cygnus X-1 /HDE 226868/

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