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Gaia Data Release 3: Exploring and mapping the diffuse interstellar band at 862 nm

Schultheis, M. ; Lindegren, L. LU orcid ; Hobbs, D. LU orcid ; McMillan, P.J. LU orcid and Zucker, S. (2023) In Astronomy and Astrophysics 674.
Abstract
Context. Diffuse interstellar bands (DIBs) are common interstellar absorption features in spectroscopic observations but their origins remain unclear. DIBs play an important role in the life cycle of the interstellar medium (ISM) and can also be used to trace Galactic structure. Aims. Here, we demonstrate the capacity of the Gaia-Radial Velocity Spectrometer (RVS) in Gaia DR3 to reveal the spatial distribution of the unknown molecular species responsible for the most prominent DIB at 862 nm in the RVS passband, exploring the Galactic ISM within a few kiloparsecs from the Sun. Methods. The DIBs are measured within the GSP-Spec module using a Gaussian profile fit for cool stars and a Gaussian process for hot stars. In addition to the... (More)
Context. Diffuse interstellar bands (DIBs) are common interstellar absorption features in spectroscopic observations but their origins remain unclear. DIBs play an important role in the life cycle of the interstellar medium (ISM) and can also be used to trace Galactic structure. Aims. Here, we demonstrate the capacity of the Gaia-Radial Velocity Spectrometer (RVS) in Gaia DR3 to reveal the spatial distribution of the unknown molecular species responsible for the most prominent DIB at 862 nm in the RVS passband, exploring the Galactic ISM within a few kiloparsecs from the Sun. Methods. The DIBs are measured within the GSP-Spec module using a Gaussian profile fit for cool stars and a Gaussian process for hot stars. In addition to the equivalent widths and their uncertainties, Gaia DR3 provides their characteristic central wavelength, width, and quality flags. Results. We present an extensive sample of 476 117 individual DIB measurements obtained in a homogeneous way covering the entire sky. We compare spatial distributions of the DIB carrier with interstellar reddening and find evidence that DIB carriers are present in a local bubble around the Sun which contains nearly no dust. We characterised the DIB equivalent width with a local density of 0.19 ± 0.04 kpc1 and a scale height of 98.60 8.46+11.10 pc. The latter is smaller than the dust scale height, indicating that DIBs are more concentrated towards the Galactic plane. We determine the rest-frame wavelength with unprecedented precision (?0 = 8620.86 ± 0.019 in air) and reveal a remarkable correspondence between the DIB velocities and the CO gas velocities, suggesting that the 862 nm DIB carrier is related to macro-molecules. Conclusions. We demonstrate the unique capacity of Gaia to trace the spatial structure of the Galactic ISM using the 862 nm DIB. © 2023 The Authors. (Less)
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keywords
Dust, extinction, ISM: kinematics and dynamics, ISM: lines and bands, Absorption spectroscopy, Dust, Life cycle, Molecules, Spectrometers, Stars, Diffuse interstellar bands, Dust extinctions, Interstellar medias, Interstellar medium: kinematic and dynamic, Interstellar medium: line and band, Kinematics and dynamics, Lines and bands, Medium kinematics, Radial velocity spectrometer, Spatial distribution
in
Astronomy and Astrophysics
volume
674
article number
A40
publisher
EDP Sciences
external identifiers
  • scopus:85163698067
ISSN
0004-6361
DOI
10.1051/0004-6361/202243283
language
English
LU publication?
yes
id
d0133d42-5f2c-44a6-a721-cc6fb8679679
date added to LUP
2023-11-16 15:29:50
date last changed
2023-11-16 15:31:57
@article{d0133d42-5f2c-44a6-a721-cc6fb8679679,
  abstract     = {{Context. Diffuse interstellar bands (DIBs) are common interstellar absorption features in spectroscopic observations but their origins remain unclear. DIBs play an important role in the life cycle of the interstellar medium (ISM) and can also be used to trace Galactic structure. Aims. Here, we demonstrate the capacity of the Gaia-Radial Velocity Spectrometer (RVS) in Gaia DR3 to reveal the spatial distribution of the unknown molecular species responsible for the most prominent DIB at 862 nm in the RVS passband, exploring the Galactic ISM within a few kiloparsecs from the Sun. Methods. The DIBs are measured within the GSP-Spec module using a Gaussian profile fit for cool stars and a Gaussian process for hot stars. In addition to the equivalent widths and their uncertainties, Gaia DR3 provides their characteristic central wavelength, width, and quality flags. Results. We present an extensive sample of 476 117 individual DIB measurements obtained in a homogeneous way covering the entire sky. We compare spatial distributions of the DIB carrier with interstellar reddening and find evidence that DIB carriers are present in a local bubble around the Sun which contains nearly no dust. We characterised the DIB equivalent width with a local density of 0.19 ± 0.04 kpc1 and a scale height of 98.60 8.46+11.10 pc. The latter is smaller than the dust scale height, indicating that DIBs are more concentrated towards the Galactic plane. We determine the rest-frame wavelength with unprecedented precision (?0 = 8620.86 ± 0.019 in air) and reveal a remarkable correspondence between the DIB velocities and the CO gas velocities, suggesting that the 862 nm DIB carrier is related to macro-molecules. Conclusions. We demonstrate the unique capacity of Gaia to trace the spatial structure of the Galactic ISM using the 862 nm DIB. © 2023 The Authors.}},
  author       = {{Schultheis, M. and Lindegren, L. and Hobbs, D. and McMillan, P.J. and Zucker, S.}},
  issn         = {{0004-6361}},
  keywords     = {{Dust, extinction; ISM: kinematics and dynamics; ISM: lines and bands; Absorption spectroscopy; Dust; Life cycle; Molecules; Spectrometers; Stars; Diffuse interstellar bands; Dust extinctions; Interstellar medias; Interstellar medium: kinematic and dynamic; Interstellar medium: line and band; Kinematics and dynamics; Lines and bands; Medium kinematics; Radial velocity spectrometer; Spatial distribution}},
  language     = {{eng}},
  publisher    = {{EDP Sciences}},
  series       = {{Astronomy and Astrophysics}},
  title        = {{Gaia Data Release 3: Exploring and mapping the diffuse interstellar band at 862 nm}},
  url          = {{http://dx.doi.org/10.1051/0004-6361/202243283}},
  doi          = {{10.1051/0004-6361/202243283}},
  volume       = {{674}},
  year         = {{2023}},
}