Deep imaging of the very isolated dwarf galaxy NGC6789

Fuente: arXiv
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Main Authors: Trujillo, Ignacio, Arencibia, Sergio Guerra, Cejudo, Ignacio Ruiz, Montes, Mireia, Alarcon, Miguel R., Serra-Ricart, Miquel
Format: Preprint
Published: 2025
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author Trujillo, Ignacio
Arencibia, Sergio Guerra
Cejudo, Ignacio Ruiz
Montes, Mireia
Alarcon, Miguel R.
Serra-Ricart, Miquel
author_facet Trujillo, Ignacio
Arencibia, Sergio Guerra
Cejudo, Ignacio Ruiz
Montes, Mireia
Alarcon, Miguel R.
Serra-Ricart, Miquel
contents We present deep optical imaging of the extremely isolated dwarf galaxy NGC 6789, obtained with the new 2-meter Two-meter Twin Telescope (TTT3) at Teide Observatory. Despite its location in the Local Void, NGC 6789 exhibits surprising recent central star formation equivalent to approximately 4% of its total stellar mass. The origin of the gas necessary for this level of star formation remains unknown. Our data reach surface brightness limits of 29.8, 29.4, and 28.9 mag arcsec$^{-2}$ in the Sloan g, r, and i filters, respectively, and reveal no evidence of tidal features or merger remnants down to $\sim$30 mag arcsec$^{-2}$ (or equivalently, at a radial distance larger than 1.6 kpc). The galaxy's undisturbed outer elliptical morphology suggests that its recent central star formation was likely produced by either in-situ residual gas or by the accretion of external pristine gas not associated with a minor merging activity.
format Preprint
id arxiv_https___arxiv_org_abs_2511_07041
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Deep imaging of the very isolated dwarf galaxy NGC6789
Trujillo, Ignacio
Arencibia, Sergio Guerra
Cejudo, Ignacio Ruiz
Montes, Mireia
Alarcon, Miguel R.
Serra-Ricart, Miquel
Astrophysics of Galaxies
Cosmology and Nongalactic Astrophysics
We present deep optical imaging of the extremely isolated dwarf galaxy NGC 6789, obtained with the new 2-meter Two-meter Twin Telescope (TTT3) at Teide Observatory. Despite its location in the Local Void, NGC 6789 exhibits surprising recent central star formation equivalent to approximately 4% of its total stellar mass. The origin of the gas necessary for this level of star formation remains unknown. Our data reach surface brightness limits of 29.8, 29.4, and 28.9 mag arcsec$^{-2}$ in the Sloan g, r, and i filters, respectively, and reveal no evidence of tidal features or merger remnants down to $\sim$30 mag arcsec$^{-2}$ (or equivalently, at a radial distance larger than 1.6 kpc). The galaxy's undisturbed outer elliptical morphology suggests that its recent central star formation was likely produced by either in-situ residual gas or by the accretion of external pristine gas not associated with a minor merging activity.
title Deep imaging of the very isolated dwarf galaxy NGC6789
topic Astrophysics of Galaxies
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2511.07041