The diffuse interstellar band around 8620 Å

Zhao, H.; Schultheis, M.; Recio–Blanco, A.; Kordopatis, G.; Laverny, P. de; Rojas-Arriagada, Á.; Zoccali, M.; Surot, F.; Valenti, E.

doi:10.1051/0004-6361/202039736

Cited by 11 publications

(13 citation statements)

References 77 publications

(179 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Two different procedures, MatisseGauguin and ANN, described in Recio-Blanco et al (2016), are applied to estimate the stellar atmospheric parameters (T eff , log(g), [M/H], and [α/Fe]). Individual chemical abundances and DIB parameters are estimated by the GAUGUIN algorithm (Recio-Blanco et al 2016) and Gaussian fitting methods (Zhao et al 2021), respectively, and are only produced by the MatisseGauguin analysis workflow 6 . The goodness-of-fit and the quality flag chain are provided for both the MatisseGauguin and ANN parametrisation.…”

Section: Goals and Outputs Of Gsp-specmentioning

confidence: 99%

GaiaData Release 3

Recio–Blanco¹,

Laverny²,

Palicio³

et al. 2023

A&A

Self Cite

108

View full text Add to dashboard Cite

Context. The chemo-physical parametrisation of stellar spectra is essential for understanding the nature and evolution of stars and of Galactic stellar populations. A worldwide observational effort from the ground has provided, in one century, an extremely heterogeneous collection of chemical abundances for about two million stars in total, with fragmentary sky coverage. Aims. This situation is revolutionised by the Gaia third data release (DR3), which contains the parametrisation of Radial Velocity Spectrometer (RVS) data performed by the General Stellar Parametriser-spectroscopy, GSP-Spec, module. Here we describe the parametrisation of the first 34 months of Gaia RVS observations. Methods. GSP-Spec estimates the chemo-physical parameters from combined RVS spectra of single stars, without additional inputs from astrometric, photometric, or spectro-photometric BP/RP data. The main analysis workflow described here, MatisseGauguin, is based on projection and optimisation methods and provides the stellar atmospheric parameters; the individual chemical abundances of N, Mg, Si, S, Ca, Ti, Cr, Fe i, Fe ii, Ni, Zr, Ce and Nd; the differential equivalent width of a cyanogen line; and the parameters of a diffuse interstellar band (DIB) feature. Another workflow, based on an artificial neural network (ANN) and referred to with the same acronym, provides a second set of atmospheric parameters that are useful for classification control. For both workflows, we implement a detailed quality flag chain considering different error sources.Results. With about 5.6 million stars, the Gaia DR3 GSP-Spec all-sky catalogue is the largest compilation of stellar chemo-physical parameters ever published and the first one from space data. Internal and external biases have been studied taking into account the implemented flags. In some cases, simple calibrations with low degree polynomials are suggested. The homogeneity and quality of the estimated parameters enables chemo-dynamical studies of Galactic stellar populations, interstellar extinction studies from individual spectra, and clear constraints on stellar evolution models. We highly recommend that users adopt the provided quality flags for scientific exploitation. Conclusions. The Gaia DR3 GSP-Spec catalogue is a major step in the scientific exploration of Milky Way stellar populations. It will be followed by increasingly large and higher quality catalogues in future data releases, confirming the Gaia promise of a new Galactic vision.

show abstract

Section: Goals and Outputs Of Gsp-specmentioning

confidence: 99%

GaiaData Release 3

Recio–Blanco¹,

Laverny²,

Palicio³

et al. 2023

A&A

Self Cite

108

View full text Add to dashboard Cite

show abstract

“…stars with T eff < 7000 K), the DIB λ862 spectral parameterisation is based on the MatisseGauguin GSP-Spec workflow. More details on the DIB λ862 measurement algorithms can be found in Zhao et al (2021a). A GSP-Spec catalogue flag was implemented (Recio-Blanco et al 2022) during the post-processing with a chain of 41 digits including all the adopted failure criteria and uncertainty sources considered during the post-processing.…”

Section: Description Of the Sample Of Diffuse Interstellar Bandsmentioning

confidence: 99%

“…where a scales the kernels, and l is the characteristic width of each kernel. We refer to Zhao et al (2021a) for a more detailed description of this process.…”

Section: Description Of the Sample Of Diffuse Interstellar Bandsmentioning

confidence: 99%

Gaia Data Release 3

Schultheis¹,

Zhao²,

Zwitter³

et al. 2023

A&A

Self Cite

View full text Add to dashboard Cite

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 Å/kpc and a scale height of 98.60 +11.10 −8.46 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 (λ 0 = 8620.86 ± 0.019 Å 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.

show abstract

“…Both algorithms are applied for atmospheric parameter estimates. Individual abundances and DIB parameters are estimated only from the Matisse-Gauguin algorithm using the approaches described in Recio-Blanco et al (2016) and Zhao et al (2021), respectively.…”

Section: General Stellar Parametrizer From Spectroscopymentioning

confidence: 99%

Gaia Data Release 3: Astrophysical parameters inference system (Apsis) I -- methods and content overview

Creevey,

Sordo,

Pailler

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

Gaia Data Release 3 contains a wealth of new data products for the community. Astrophysical parameters are a major component of this release. They were produced by the Astrophysical parameters inference system (Apsis) within the Gaia Data Processing and Analysis Consortium. The aim of this paper is to describe the overall content of the astrophysical parameters in Gaia DR3 and how they were produced. In Apsis we use the mean BP/RP and mean RVS spectra along with astrometry and photometry, and we derive the following parameters: source classification and probabilities for 1.6 billion objects, interstellar medium characterisation and distances for up to 470 million sources, including a 2D total Galactic extinction map, 6 million redshifts of quasar candidates and 1.4 million redshifts of galaxy candidates, along with an analysis of 50 million outlier sources through an unsupervised classification. The astrophysical parameters also include many stellar spectroscopic and evolutionary parameters for up to 470 million sources. These comprise T eff , log g, and [M/H] (470 million using BP/RP, 6 million using RVS), radius (470 million), mass (140 million), age (120 million), chemical abundances (up to 5 million), diffuse interstellar band analysis (0.5 million), activity indices (2 million), Hα equivalent widths (200 million), and further classification of spectral types (220 million) and emission-line stars (50 thousand). This paper is part of a series of three papers: this Paper I focusses on describing the global content of the parameters in Gaia DR3. The accompanying papers II and III focus on the validation and use of the stellar and non-stellar products, respectively. This catalogue is the most extensive homogeneous database of astrophysical parameters to date, and it is based uniquely on Gaia data. It will only be superseded in Gaia Data Release 4. This catalogue will therefore remain a key reference over the next four years, providing astrophysical parameters independent of other ground-and space-based data.

show abstract

The diffuse interstellar band around 8620 Å

Cited by 11 publications

References 77 publications

GaiaData Release 3

GaiaData Release 3

Gaia Data Release 3

Gaia Data Release 3: Astrophysical parameters inference system (Apsis) I -- methods and content overview

Contact Info

Product

Resources

About