DDO68 C: The Actual Appearance of a Ghost Satellite Dwarf through Adaptive Optics at the Large Binocular Telescope

Francesca Annibali; Enrico Pinna; Leslie K. Hunt; Diego Paris; Felice Cusano; Michele Bellazzini; John M. Cannon; Raffaele Pascale; Monica Tosi; Fabio Rossi

doi:10.3847/2041-8213/acab63

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DDO68 C: The Actual Appearance of a Ghost Satellite Dwarf through Adaptive Optics at the Large Binocular Telescope

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DDO68 C: The Actual Appearance of a Ghost Satellite Dwarf through Adaptive Optics at the Large Binocular Telescope

Francesca Annibali, Enrico Pinna, Leslie K. Hunt, Diego Paris, Felice Cusano, Michele Bellazzini, John M. Cannon, Raffaele Pascale, Monica Tosi and Fabio Rossi

Astrophysical journal. Letters, Vol.942(1), p.L23

01/01/2023

DOI: 10.3847/2041-8213/acab63

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Abstract

Through adaptive optics (AO) imaging with the SOUL+LUCI instrument at the Large Binocular Telescope we were able to resolve, for the first time, individual stars in the gas-rich galaxy DDO68 C. This system was already suggested to be interacting with the extremely metal-poor dwarf DDO68, but its nature has remained elusive so far because of the presence of a bright foreground star close to its line of sight that hampers a detailed study of its stellar population and distance. In our study, we turned this interloper star into an opportunity to have a deeper insight on DDO68 C, using it as a guide star for the AO correction. Although the new data do not allow for a direct distance measurement through the red giant branch tip method, the combined analysis of the resolved-star color–magnitude diagram, of archival GALEX far-UV and near-UV photometry, and of Hα data provides a self-consistent picture in which DDO68 C is at the same ∼13 Mpc distance as its candidate companion DDO68. These results indicate that DDO68 is a unique case of a low-mass dwarf, less massive than the Magellanic Clouds, interacting with three satellites (DDO68 C and two previously confirmed accreting systems), providing useful constraints on cosmological models and a potential explanation for its anomalous extremely low metallicity.

Adaptive optics

Dwarf galaxies

Dwarf irregular galaxies

Galaxy stellar content

Interacting galaxies

Details

Title: Subtitle: DDO68 C: The Actual Appearance of a Ghost Satellite Dwarf through Adaptive Optics at the Large Binocular Telescope
Creators: Francesca Annibali - National Institute for Astrophysics
Enrico Pinna - Arcetri Astrophysical Observatory
Leslie K. Hunt - Arcetri Astrophysical Observatory
Diego Paris - Astronomical Observatory of Rome
Felice Cusano - National Institute for Astrophysics
Michele Bellazzini - National Institute for Astrophysics
John M. Cannon - Macalester College
Raffaele Pascale - National Institute for Astrophysics
Monica Tosi - National Institute for Astrophysics
Fabio Rossi - Arcetri Astrophysical Observatory
Resource Type: Journal article
Publication Details: Astrophysical journal. Letters, Vol.942(1), p.L23
Publisher: The American Astronomical Society
DOI: 10.3847/2041-8213/acab63
ISSN: 2041-8205
eISSN: 2041-8213
Number of pages: 9
Grant note: 1.05.01.88.04 / Istituto Nazionale di Astrofisica (INAF) (https://doi.org/10.13039/501100005184) 1.05.01.86.28 / Istituto Nazionale di Astrofisica (INAF) (https://doi.org/10.13039/501100005184)
Language: English
Date published: 01/01/2023
Academic Unit: Physics and Astronomy
Record Identifier: 9984627238602771

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