Ultrafine Structure in the λ5797 Diffuse Interstellar Absorption Band

Kerr, Tom; Hibbins, R. E.; Fossey, S. J.; Miles, J. R.; Sarre, P. J.

doi:10.1086/305339

Cited by 61 publications

(72 citation statements)

References 24 publications

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“…Some previously published, high-resolution profiles of strong DIBs show complex profiles that suggest a molecular pattern (Sarre et al 1995;Kerr et al 1998). This fact supports the hypothesis of some complex molecular species as their carriers.…”

Section: Discussionsupporting

confidence: 76%

“…The spectra with the highest resolution, acquired with the Ultra High Resolution Facility (R = 600 000), demonstrated a similarity between the 5797 and 6614 DIB profiles (Sarre et al 1995;Kerr et al 1998). The latter seem to contain substructures that could be P, R, and Q branches of the rotational contours for the bands of some complex molecules.…”

Section: Introductionmentioning

confidence: 90%

See 1 more Smart Citation

A search for fine structure inside high resolution profiles of weak diffuse interstellar bands

Słyk

Галазутдинов²,

Мусаев

et al. 2006

A&A

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This paper presents a survey of the high-resolution profiles of selected, moderately weak diffuse interstellar bands (DIBs) between 4725 and 6730 Å. In very high signal-to-noise spectra, obtained as a result of averaging several individual exposures of reddened, early-type stars that show Doppler splitting of <2 km s −1 in interstellar gas lines, the profiles seem to have a substructure. This supports the molecular origin hypothesis for DIBs. We studied the profiles of the diffuse interstellar bands at wavelengths

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Section: Discussionsupporting

confidence: 76%

Section: Introductionmentioning

confidence: 90%

A search for fine structure inside high resolution profiles of weak diffuse interstellar bands

Słyk

Галазутдинов²,

Мусаев

et al. 2006

A&A

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show abstract

“…The latter cannot be true as the FWHM of the 5797 Å DIB does not exceed that value and the intrinsic width of the DIBs is certainly more than a few tenths of Å (see below for further discussion). If impurities in the carrier cause additional sub-structure, e.g., as seen in the 5797 Å by Kerr et al (1998) and/or broadening then one could envisage a scenario in which such impurities are suppressed in a metal-depleted environment such as that of the LMC as compared to that of the Milky Way Disc (Milky Way Halo clouds being metal-poor).…”

Section: Band Profilesmentioning

confidence: 99%

The VLT-FLAMES Tarantula Survey

Loon

Bailey

Tatton

et al. 2013

A&A

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Context. The Tarantula Nebula (a.k.a. 30 Dor) is a spectacular star-forming region in the Large Magellanic Cloud (LMC), seen through gas in the Galactic disc and halo. Diffuse interstellar bands (DIBs) offer a unique probe of the diffuse, cool-warm gas in these regions. Aims. The aim is to use DIBs as diagnostics of the local interstellar conditions, whilst at the same time deriving properties of the yet-unknown carriers of these enigmatic spectral features. Methods. Spectra of over 800 early-type stars from the Very Large Telescope Flames Tarantula Survey (VFTS) were analysed. Maps were created, separately, for the Galactic and LMC absorption in the DIBs at 4428 and 6614 Å and -in a smaller region near the central cluster R 136 -neutral sodium (the Na i D doublet); we also measured the DIBs at 5780 and 5797 Å.Results. The maps show strong 4428 and 6614 Å DIBs in the quiescent cloud complex to the south of 30 Dor but weak absorption in the harsher environments to the north (bubbles) and near the OB associations. The Na maps show at least five kinematic components in the LMC and a shell-like structure surrounding R 136, and small-scale structure in the Milky Way. The strengths of the 4428, 5780, 5797 and 6614 Å DIBs are correlated, also with Na absorption and visual extinction. The strong 4428 Å DIB is present already at low Na column density but the 6614, 5780 and 5797 Å DIBs start to be detectable at subsequently larger Na column densities. Conclusions. The carriers of the 4428, 6614, 5780 and 5797 Å DIBs are increasingly prone to removal from irradiated gas. The relative strength of the 5780 and 5797 Å DIBs clearly confirm the Tarantula Nebula as well as Galactic high-latitude gas to represent a harsh radiation environment. The resilience of the 4428 Å DIB suggests its carrier is large, compact and neutral. Structure is detected in the distribution of cool-warm gas on scales between one and >100 pc in the LMC and as little as 0.01 pc in the Sun's vicinity. Stellar winds from the central cluster R 136 have created an expanding shell; some infalling gas is also detected, reminiscent of a galactic "fountain".

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“…Cossart-Magos and Leach [31] and Edwards and Leach [32] used thermal distributions with T ex = 3 K, although their Figure 1. Spectra (resolving power of 600,000 at AAT and 300,000 at KPNO) of the λ5797.1 DIB, originally published as Figure 2 in Kerr et al [33]. Reprinted with permission of the main author (P. J. Sarre) and The Astrophysical Journal.…”

Section: Introductionmentioning

confidence: 99%

“…The substructures of the λ5797.1 DIB were first studied at very high resolutions by Sarre's group in the spectra of the stars µ Sgr, ζ Per, and ζ Oph [20,33]. Figure 1 shows Kerr et al's spectra of the λ5797.1 band for three lines of sight, observed either at the Anglo-Australian Telescope (AAT) at a resolving power of 600,000 or at Kitt Peak National Observatory at a resolving power of 300,000 [33]. As seen in all three lines of sight, the λ5797.1 DIB shows a narrow spectral feature at its center, with two peaks on either side that are wider but at a similar depth.…”

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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Ultrafine Structure in the λ5797 Diffuse Interstellar Absorption Band

Cited by 61 publications

References 24 publications

A search for fine structure inside high resolution profiles of weak diffuse interstellar bands

A search for fine structure inside high resolution profiles of weak diffuse interstellar bands

The VLT-FLAMES Tarantula Survey

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

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