The GALAH survey : new diffuse interstellar bands found in residuals of 872 000 stellar spectra

Vogrinčič, Rok (author), Kos, Janez (author), Zwitter, Tomaž (author), Traven, Gregor (author), Beeson, Kevin Luke (author), Čotar, Klemen (author)

We use more than 872 000 mid- to high-resolution (R ∼ 20 000) spectra of stars from the GALactic Archaeology with HERMES (GALAH) survey to discern the spectra of diffuse interstellar bands (DIBs). We use four windows with the wavelength ranges 4718–4903, 5649–5873, 6481–6739, and 7590–7890 Å, giving a total coverage of 967 Å. We produce ∼400 000 spectra of interstellar medium (ISM) absorption features and correct them for radial velocities of the DIB clouds. Ultimately, we combine the 33 115 best ISM spectra into six reddening bins with a range of 0.1 < E(B − V) < 0.7 mag. A total of 183 absorption features in these spectra qualify as DIBs, and their fitted model parameters are summarized in a detailed catalogue. From these, 64 are not reported in the literature, of which 17 are certain, 14 are probable and 33 are possible. We find that the broad DIBs can be fitted with a multitude of narrower DIBs. Finally, we create a synthetic DIB spectrum at unit reddening. This should allow us to narrow down the possible carriers of DIBs, to explore the composition of the ISM, and ultimately to model dust and star formation better as well as to correct Galactic and extragalactic observations. The majority of certain DIBs show a significant excess of equivalent width when compared with reddening. We explain this with observed lines of sight penetrating more uniform DIB clouds compared with clumpy dust clouds.

• Language: English
• Keywords: catalogues, spectroscopic surveys, methods, data analysis, surveys, dust, extinction
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FMF - Faculty of Mathematics and Physics
• Publication status: Published
• Publication version: Version of Record
• Year: 2023
• Number of pages: Str. 3727-3748
• Numbering: Vol. 521, iss. 3
• PID: 20.500.12556/RUL-147271
• UDC: 524.3
• ISSN on article: 1365-2966
• DOI: 10.1093/mnras/stad678
• COBISS.SI-ID: 152621827
• Publication date in RUL: 28.06.2023

Record is a part of a journal

• Title: Monthly notices of the Royal Astronomical Society
• Shortened title: Mon. not. R. Astron. Soc.
• Publisher: Blackwell Science
• ISSN: 1365-2966
• COBISS.SI-ID: 1870180

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.