Emission from dust in visual reflection nebulae at infrared and submillimeter wavelengths

Casey, S. C.

doi:10.1086/169882

Cited by 33 publications

(39 citation statements)

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“…An enhancement of this kind might explain the factor 3 difference between Q(850 µm) derived by Alton et al (2000) for the H 2 -dominated galaxy NGC 891 and the corresponding value produced by Boulanger et al (1996) for the HI phase of the Milky Way. Enhancements of this order have also been noted by observers of reflection nebulae and dense star-forming regions (Andre et al 1993;Rengarajan 1984;Sopka et al 1985;Casey 1991;see also Fig. 2) and are expected on the basis of grain conglomeration and mantle formation (Ossenkopf & Henning 1994;Mathis & Whiffen 1989).…”

Section: Conversion To Optical Depthsupporting

confidence: 59%

“…The exponential scale-height of disk stars, above the midplane, was fixed at 0.3 kpc and the corresponding value for the dust was set at half this value. This "sandwiching" of the main dust disk by a more vertically extensive distribution of stars is indicated by optical (Hildebrand 1983;Casey 1991), deeply-embedded FIR sources (Rengarajan 1984), dust envelopes of evolved stars (Sopka et al 1985) and the edge-on spiral NGC 891 (Alton et al 2000). Agladze et al (1994) refers to laboratory experiments conducted on silicate particulates.…”

Section: Conversion To Optical Depthmentioning

confidence: 98%

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Deep submillimeter images of NGC 7331; dust at the periphery of spiral disks

Alton

Lequeux

Bianchi³

et al. 2001

A&A

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Abstract. We present deep 450 and 850 µm SCUBA images of the nearby spiral galaxy NGC 7331. Using the submillimeter emissivity inferred from COBE observations of Milky Way dust, we convert our SCUBA images into maps of optical depth. The opacity derived in this way is quite low at the visible limit of NGC 7331 (τB ≤ 0.22 at the R25 radius for the disk seen face-on). In a similar fashion, we exploit SCUBA and ISOPHOT images of a further 10 galaxies and, collectively, these data indicate τB = 0.1-0.2 at the R25 radius. Our constraints on disk opacity are fed into a simulation of how light emanating from high redshifts is attenuated by foreground spirals. In making this calculation, we consider the possibility that galactic disks may have also contained different dust masses in the past. We estimate that less than 10% of the light emitted by Hubble Deep Field galaxies fails to reach the B-band observer due to intervening spirals.

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Section: Conversion To Optical Depthsupporting

confidence: 59%

Section: Conversion To Optical Depthmentioning

confidence: 98%

Deep submillimeter images of NGC 7331; dust at the periphery of spiral disks

Alton

Lequeux

Bianchi³

et al. 2001

A&A

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“…Ced 201 is a rather compact object at a distance of 420 pc (Casey 1991), on the edge of a molecular cloud. It is excited by the B9.5 V star BD +69 1231.…”

Section: Ced 201mentioning

confidence: 99%

Blue Luminescence and the Presence of Small Polycyclic Aromatic Hydrocarbons in the Interstellar Medium

Vijh

Witt

2005

ApJ

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Blue luminescence (BL) was first discovered in a proto-planetary nebula, the Red Rectangle (RR), surrounding the post-AGB star HD 44179. BL has been attributed to fluorescence by small, 3-4 ringed neutral polycyclic aromatic hydrocarbon (PAH) molecules and was thought to be unique to the RR environment, where such small molecules are actively being produced and shielded from the harsh interstellar radiation by a dense circumstellar disk. In this paper we present the BL spectrum detected in several ordinary reflection nebulae illuminated by stars having temperatures between 10,000 and 23,000 K. All these nebulae are known to also exhibit the infrared emission features called aromatic emission features (AEFs) attributed to large PAHs. We present the spatial distribution of the BL in these nebulae. In the case of Ced 112, the BL is spatially correlated with mid-IR emission structures attributed to AEFs. These observations provide evidence for grain processing and possibly for in situ formation of small grains and large molecules from larger aggregates. Most importantly, the detection of BL in these ordinary reflection nebulae suggests that the BL carrier is an ubiquitous component of the interstellar medium and is not restricted to the particular environment of the RR.

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“…The relation between cirrus sub-mm emission and optical extinction has been discussed by Hildebrand (1983), Casey (1991) and Bianchi, Davies & Alton (1999). It turns out that the integrated submm flux from a galaxy, with certain assumptions, scales linearly with A V .…”

Section: Discussionmentioning

confidence: 91%

“…Since sub-mm emission measures physical dust volume rather than the volume of space the dust is dispersed in, the same level of sub-mm emission can arise from a comparable mass of dust distributed in the disk of a galaxy, heated by the general interstellar radiation field. This type of sub-mm emission, known as 'cirrus' emission, is seen locally, both in Galactic sources (Casey 1991), and in nearby galaxies (Bianchi, Davies & Alton 1999;Dunne et al 2000). Furthermore, there is evidence that cirrus emission may be important in blank-field sub-mm sources (Efstathiou & Rowan-Robinson 2003).…”

Section: Discussionmentioning

confidence: 99%