Volume density maps of the 862nm DIB carrier and interstellar dust: a hint for the role of carbon-rich ejecta from AGB stars?

Abstract

The carbonaceous macromolecules imprinting in astronomical spectra the numerous absorptions called Diffuse Interstellar Bands (DIBs) are omnipresent in the Galaxy and beyond and represent a considerable reservoir of organic matter. However, their chemical formulae, formation and destruction sites remain open questions. Their spatial distribution and the local relation to other interstellar species is paramount to unravel their role in the lifecycle of organic matter. Volume density maps bring local instead of line-of-sight distributed information, and allow for new diagnostics. We present the first large-scale volume (3D) density map of a DIB carrier and compare it with an equivalent map of interstellar dust. The DIB carrier map is obtained through hierarchical inversion of about 202,000 measurements of the 8621 nm DIB obtained with the Gaia-RVS instrument. It covers about 4000 pc around the Sun in the Galactic plane. A dedicated interstellar dust map is built based on extinction towards the same target stars. At the 50 pc resolution of the maps, the 3D DIB distribution is found remarkably similar in shape to the 3D distribution of dust. On the other hand, the DIB-to-dust local density ratio increases in low-dust areas. It is also increasing away from the disk, however, the minimum ratio is found to be shifted above the Plane to Z = +50pc. Finally, the average ratio is also surprisingly found to increase away from the Galactic Center. We suggest that the three latter trends may be indications of a dominant contribution of material from the carbon-rich category of dying giant stars to the formation of the carriers. Our suggestion is based on recent catalogues of AGB stars and estimates of their mass fluxes of C-rich and O-rich ejecta.

12 pages, 11 figures, accepted for publication in Astronomy and Astrophysics

References in corpus (19)

• The Gaia mission
• Gaia Data Release 3: Summary of the content and survey properties
• Updated Gaia-2MASS 3D maps of Galactic interstellar dust
• Resolving nearby dust clouds
• Three-dimensional extinction maps: Inverting inter-calibrated extinction catalogues
• Confirming interstellar C${}_{60}^{+}$ using the Hubble Space Telescope
• Mapping the Interstellar Medium with Near-Infrared Diffuse Interstellar Bands
• Pseudo Three-dimensional Maps of the Diffuse Interstellar Band at 862 nm
• The Gaia-ESO Survey: Extracting diffuse interstellar bands from cool star spectra, DIB-based interstellar medium line-of-sight structures at the kpc scale
• Detailed 3D structure of OrionA in dust with Gaia DR2
• A Principal component analysis of the diffuse interstellar bands
• Dusting off the diffuse interstellar bands: DIBs and dust in extragalactic SDSS spectra
• The Behavior of Selected Diffuse Interstellar Bands with Molecular Fraction in Diffuse Atomic and Molecular Clouds
• Gaia Data Release 3: Exploring and mapping the diffuse interstellar band at 862 nm
• A three-dimensional map of the hot Local Bubble using diffuse interstellar bands
• Carbon- and Oxygen-rich Asymptotic Giant Branch (AGB) stars in the Bulge Asymmetries and Dynamical Evolution (BAaDE) survey
• The 15273 Å diffuse interstellar band in the dark cloud Barnard 68
• 3D maps of the local interstellar medium: searching for the imprints of past events
• Characterizing the Evolved Stellar Population in the Galactic Foreground I: Bolometric Magnitudes, Spatial Distribution and P-L Relations

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