Studies of NIR Dust Absorption Features in the Nuclei of Active and IRAS Galaxies

Wright, Gillian; Bridger, Alan; Geballe, T. R.; Pendleton, Y. J.

doi:10.1007/978-94-009-0335-7_16

Cited by 19 publications

(20 citation statements)

References 13 publications

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“…Imanishi et al (1997) calculate 3:42 ¼ 0:126 AE 0:014, slightly larger than the 3:42 ¼ 0:1 derived by Wright et al (1996). We measure 3:42 % 0:09.…”

Section: Optical Depth Spectramentioning

confidence: 53%

“…In almost all cases, the observations were aimed at establishing the power source of each galaxy through the presence or absence of the 3.4 m band and the 3.3 m polycyclic aromatic hydrocarbon (PAH) emission feature, rather than to examine in detail the chemical makeup of the dust. Wright et al (1996) and Imanishi et al (1997) note the similarity of the 3.4 m feature in the Seyfert 2 galaxy NGC 1068 with that observed toward the Galactic center, and Wright et al (1996) and Pendleton (1996Pendleton ( , 1997 also compare the feature in the ULIRG IRAS 08572+3915 to the Galactic center, again finding a striking similarity. Risaliti et al (2003) present an L-band spectrum of the southern nucleus of the Superantennae galaxy (IRAS 19254À7245) and suggest that the 3.4 m feature profile implies that the carbonaceous dust in that galaxy contains more electronegative groups than that in the Galactic diffuse ISM.…”

Section: Introductionmentioning

confidence: 62%

“…The deepest 3.4 m features yet observed in any lines of sight are found in the ULIRGs (L IR > 10 12 L ) IRAS 08572+ 3915, IRAS 19254À7245, and UGC 5101, along with a weaker feature in IRAS 05189À2524 (Wright et al 1996;Imanishi & Dudley 2000;Imanishi et al 2001;Risaliti et al 2003), leading to the suggestion that the major power source in each of these ULIRGs is a deeply obscured AGN. This could mean that the feature arises in dust close to the active nucleus, as is the case for some of the Seyfert galaxies.…”

Section: The Ulirgsmentioning

confidence: 99%

“…The observations and reduction of the data are described in Imanishi et al (2001) and Imanishi (2003). The spectrum of IRAS 05189À2524 is from Wright et al (1996).…”

Section: The Ulirgsmentioning

confidence: 99%

“…The 3.4 m band has also been detected in several Seyfert galaxies and ultraluminous infrared galaxies (ULIRGs; Bridger et al 1994;Mizutani et al 1994;Wright et al 1996;Imanishi et al 1997Imanishi et al , 2001Imanishi 2000aImanishi , 2000bImanishi , 2002Imanishi , 2003Imanishi & Dudley 2000;Marco & Brooks 2003;Risaliti et al 2003). In almost all cases, the observations were aimed at establishing the power source of each galaxy through the presence or absence of the 3.4 m band and the 3.3 m polycyclic aromatic hydrocarbon (PAH) emission feature, rather than to examine in detail the chemical makeup of the dust.…”

Section: Introductionmentioning

confidence: 99%

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Hydrocarbon Dust Absorption in Seyfert Galaxies and Ultraluminous Infrared Galaxies

Mason¹,

Wright²,

Pendleton³

et al. 2004

ApJ

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We present new spectroscopic observations of the 3.4 m absorption feature in the Seyfert galaxies NGC 1068 and NGC 7674 and the ultraluminous infrared galaxy IRAS 08572+3915. A signature of CÀH bonds in aliphatic hydrocarbons, the 3.4 m feature indicates the presence of organic material in Galactic and extragalactic dust. Here we compare the 3.4 m feature in all the galaxies in which it has been detected. In several cases, the signalto-noise ratio and spectral resolution permit a detailed examination of the feature profile, something which has rarely been attempted in extragalactic lines of sight. The 3.4 m band in these galaxies closely resembles that seen in the Galactic diffuse interstellar medium (ISM) and in newly formed dust in a protoplanetary nebula. The similarity implies a common carrier for the carbonaceous component of dust, and one which is resistant to processing in the interstellar and /or circumnuclear medium. We also examine the mid-IR spectrum of NGC 1068, because absorption bands in the 5-8 m region further constrain the chemistry of the 3.4 m band carrier. While weak features like those present in the mid-IR spectrum of diffuse dust toward the Galactic center would be undetectable in NGC 1068, the strong bands found in the spectra of many proposed dust analog materials are clearly absent, eliminating certain candidates and production mechanisms for the carrier. The absence of strong absorption features at 5-8 m is also consistent with the interpretation that the similarity in the 3.4 m feature in NGC 1068 to that in Galactic lines of sight reflects real chemical similarity in the carbonaceous dust.

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“…Imanishi et al (1997) calculate 3:42 ¼ 0:126 AE 0:014, slightly larger than the 3:42 ¼ 0:1 derived by Wright et al (1996). We measure 3:42 % 0:09.…”

Section: Optical Depth Spectramentioning

confidence: 53%

Section: Introductionmentioning

confidence: 62%

Section: The Ulirgsmentioning

confidence: 99%

“…The observations and reduction of the data are described in Imanishi et al (2001) and Imanishi (2003). The spectrum of IRAS 05189À2524 is from Wright et al (1996).…”

Section: The Ulirgsmentioning

confidence: 99%