INSPIRE: INvestigating Stellar Populations In RElics – IX. KiDS J0842 + 0059: the first fully confirmed relic beyond the local Universe

ABSTRACT Relics are massive, compact and quiescent galaxies that assembled the majority of their stars in the early Universe and lived untouched until today, completely missing any subsequent size growth caused by mergers and interactions. They provide the unique opportunity to put constraints on the first phase of mass assembly in the Universe with the ease of being nearby. While only a few relics have been found in the local Universe, the INSPIRE project has confirmed 38 relics at higher redshifts ($z \sim 0.2{\small --}0.4$), fully characterizing their integrated kinematics and stellar populations. However, given the very small sizes of these objects and the limitations imposed by the atmosphere, structural parameters inferred from ground-based optical imaging are possibly affected by systematic effects that are difficult to quantify. In this paper, we present the first high-resolution image obtained with Adaptive Optics Ks-band observations on SOUL-LUCI@LBT of one of the most extreme INSPIRE relics, KiDS J0842 + 0059 at $z \sim 0.3$. We confirm the discy morphology of this galaxy (axis ratio of 0.24) and its compact nature (circularized effective radius of $\sim 1$ kpc) by modelling its 2D surface brightness profile with a point-spread function-convolved Sérsic model. We demonstrate that the surface mass density profile of KiDS J0842 + 0059 closely resembles that of the most extreme local relic, NGC 1277, as well as of high-redshift red nuggets. We unambiguously conclude that this object is a remnant of a high-redshift compact and massive galaxy, which assembled all of its mass at $z>2$, and completely missed the merger phase of the galaxy evolution at high redshift.

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Journal
Monthly Notices of the Royal Astronomical Society
Published
2025-05-30
DOI
https://doi.org/10.1093/mnras/staf831
Citations
2
Primary Topic
Stellar, planetary, and galactic studies
Type
article
Field-Weighted Citation Impact
2.31

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article

INSPIRE: INvestigating Stellar Populations In RElics – IX. KiDS J0842 + 0059: the first fully confirmed relic beyond the local Universe

L. K. Hunt, N. R. Napolitano, Giulia Carlà, G. Tozzi et al.
2 citations
Monthly Notices of the Royal Astronomical Society
Stellar, planetary, and galactic studies
2.31
article

INSPIRE: INvestigating Stellar Populations In RElics – IX. KiDS J0842 + 0059: the first fully confirmed relic beyond the local Universe

L. K. Hunt, N. R. Napolitano, Giulia Carlà, G. Tozzi, Marilena Spavone, Johanna Hartke, F. La Barbera, Chiara Spiniello, P. Saracco, Enrico Pinna, M. Arnaboldi, C. Pulsoni, Davide Bevacqua, Guido Agapito, Anna Ferré-Mateu, C. Tortora, G. D’Ago, F. Mannucci, Diana Scognamiglio, Anna Gallazzi, Essna Ghose, Michalina Maksymowicz-Maciata, Rui Li
article en
2 citations

Abstract

ABSTRACT Relics are massive, compact and quiescent galaxies that assembled the majority of their stars in the early Universe and lived untouched until today, completely missing any subsequent size growth caused by mergers and interactions. They provide the unique opportunity to put constraints on the first phase of mass assembly in the Universe with the ease of being nearby. While only a few relics have been found in the local Universe, the INSPIRE project has confirmed 38 relics at higher redshifts ($z \sim 0.2{\small --}0.4$), fully characterizing their integrated kinematics and stellar populations. However, given the very small sizes of these objects and the limitations imposed by the atmosphere, structural parameters inferred from ground-based optical imaging are possibly affected by systematic effects that are difficult to quantify. In this paper, we present the first high-resolution image obtained with Adaptive Optics Ks-band observations on SOUL-LUCI@LBT of one of the most extreme INSPIRE relics, KiDS J0842 + 0059 at $z \sim 0.3$. We confirm the discy morphology of this galaxy (axis ratio of 0.24) and its compact nature (circularized effective radius of $\sim 1$ kpc) by modelling its 2D surface brightness profile with a point-spread function-convolved Sérsic model. We demonstrate that the surface mass density profile of KiDS J0842 + 0059 closely resembles that of the most extreme local relic, NGC 1277, as well as of high-redshift red nuggets. We unambiguously conclude that this object is a remnant of a high-redshift compact and massive galaxy, which assembled all of its mass at $z>2$, and completely missed the merger phase of the galaxy evolution at high redshift.

Monthly Notices of the Royal Astronomical SocietyVol. 540(3)
University of Insubria (IT), European Southern Observatory (DE), Jet Propulsion Laboratory (US), University of Turku (FI), Universidad de La Laguna (ES), Turku Centre for Computer Science (FI), University of Cambridge (GB), Arcetri Astrophysical Observatory (IT), Astronomical Observatory of Capodimonte (IT), Brera Astronomical Observatory (IT), University of Bristol (GB), Zhengzhou University (CN), University of Oxford (GB), Max Planck Institute for Extraterrestrial Physics (DE), Federico II University Hospital (IT), Institute of Astronomy (RU), Instituto de Astrofísica de Canarias (ES), Bristol Robotics Laboratory (GB), University of Naples Federico II (IT)
National Aeronautics and Space Administration, California Institute of Technology, UK Research and Innovation, European Commission, HORIZON EUROPE Framework Programme, Science and Technology Facilities Council, Agencia Estatal de Investigación
Openalex Percentile: Top 12%
Stellar, planetary, and galactic studies
2.31
DOIOpen Access PDFOpenAlex
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