Profiles of the λ6196 and λ6379 Diffuse Interstellar Bands

Walker, G. A. H.; Webster, Adrian; Bohlender, D.; Krełowski, J.

doi:10.1086/323208

Cited by 35 publications

(36 citation statements)

References 19 publications

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“…they apparently depend on physical parameters of interstellar clouds. This phenomenon was shown in the case of 6196, 6379 and 6614 DIBs in the recent papers by Walker et al (2001).…”

Section: Introductionmentioning

confidence: 61%

Fine structure of profiles of weak diffuse interstellar bands

Галазутдинов

Stachowska

Мусаев

et al. 2002

A&A

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Abstract. We present a very high resolution (R = 120 000-220 000) analysis of profiles of selected diffuse interstellar bands (DIBs): 4964, 4980, 4985, 5850 Å. The 4980 Å feature is a very weak one, yet some substructures are proved to be present, as well as within the profiles of another stronger ones where this phenomenon was found several years ago. The presence of substructures inside DIB profiles supports their molecular origin.

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“…they apparently depend on physical parameters of interstellar clouds. This phenomenon was shown in the case of 6196, 6379 and 6614 DIBs in the recent papers by Walker et al (2001).…”

Section: Introductionmentioning

confidence: 61%

Fine structure of profiles of weak diffuse interstellar bands

Галазутдинов

Stachowska

Мусаев

et al. 2002

A&A

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“…Using the two (extreme) single cloud profiles (µ Sgr and ρ Oph; cf. the profiles of ζ Oph and σ Sco in Walker et al 2001) an uncertainty of only 2.5 km s −1 is introduced in the least-squares velocity due to the difference in fine structure. Therefore we conclude that this method, which takes some account of the DIB profile shape, is preferable to fitting with a Gaussian.…”

Section: Diffuse Interstellar Bands In the Largementioning

confidence: 99%

The Large Magellanic Cloud: diffuse interstellar bands, atomic lines and the local environmental conditions

Cox

Cordiner

Cami

et al. 2006

A&A

102

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The Large Magellanic Cloud (LMC) offers a unique laboratory to study the diffuse interstellar bands (DIBs) under conditions that are profoundly different from those in the Galaxy. DIB carrier abundances depend on several environmental factors, in particular the local UV radiation field. In this paper we present measurements of twelve DIBs in five lines of sight to early-type stars in the LMC, including the 30 Doradus region. From the high resolution spectra obtained with VLT/UVES we also derive environmental parameters that characterise the local interstellar medium (ISM) in the probed LMC clouds. These include the column density components (including total column density) for the atomic resonance lines of Na i, Ca ii, Ti ii, K i. In addition, we derive the H i column density from 21 cm line profiles, the total-to-selective visual extinction R V and the gas-to-dust ratio N(H i)/A V . Furthermore, from atomic line ratios we derive the ionisation balance and relative UV field strength in these environments. We discuss the properties of the LMC ISM in the context of DIB carrier formation. The behaviour of DIBs in the LMC is compared to that of DIBs in different local environmental conditions in the Milky Way. A key result is that in most cases the diffuse band strengths are weak (up to factor 5) with respect to Galactic lines of sight of comparable reddening, E B−V . In the line of sight towards Sk -69 223 the 5780 and 5797 Å DIBs are very similar in strength and profile to those observed towards HD 144217, which is typical of an environment exposed to a strong UV field. From the velocity analysis we find that DIB carriers (towards Sk -69 243) are better correlated with the ionised species like Ca ii than with neutrals (like Na i and CO). The most significant parameter that governs the behaviour of the DIB carrier is the strength of the UV field.

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“…The sharpness of these DIBs and substructures in some of these bands provide evidence that these DIBs are due to electronic transitions of gas-phase molecules [19][20][21]. High-resolution spectra of these bands has facilitated rotational contour fittings of DIB profiles, thereby enabling plausible sizes and geometries of carrier molecules to be assessed [21][22][23][24][25]. In this paper we attempt to simulate the observed profile of λ5797.1, which has distinctive features that we believe are the most revealing of the properties of its carrier.…”

Section: Introductionmentioning

confidence: 99%

Constraining the size of the carrier of the λ5797.1 diffuse interstellar band

Huang

Oka

2015

Molecular Physics

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The diffuse interstellar band (DIB) at 5797.1Å is simulated based on three premises: (1) The carrier of the DIB is polar as concluded by T. Oka et al. from the anomalous spectrum toward Herschel 36. (2) The sharp central feature observed by P. J. Sarre's group is the Qbranch of a parallel band of a prolate top. (3) The radiative temperature of the environment is Tr = 2.73 K.A 2 Π ← 2 Π transition of a linear radical is simulated. Results depend on 10 parameters, with the rotational constant B being the most critical. Comparisons of calculated spectra with observed data constrain B, which in turn constrains the number of heavy atoms to 5 ≤ n ≤ 7. Upper limits based on the Her 36 spectrum and lower limits based on stability against photodissociation are also discussed. The latter is based on the assumption that the DIB molecules are produced top-down from the breakdown of dust rather than bottom-up by chemical reactions.A difficulty with this limit is that J. P. Maier's laboratory has observed many molecules within this size range, some of which have been tested astronomically. Candidates are discussed in light of many prolate tops observed by the P. Thaddeus and M. C. McCarthy microwave group.

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Profiles of the λ6196 and λ6379 Diffuse Interstellar Bands

Cited by 35 publications

References 19 publications

Fine structure of profiles of weak diffuse interstellar bands

Fine structure of profiles of weak diffuse interstellar bands

The Large Magellanic Cloud: diffuse interstellar bands, atomic lines and the local environmental conditions

Constraining the size of the carrier of the λ5797.1 diffuse interstellar band

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