First confirmed ultra-compact dwarf galaxy in the NGC 5044 group

Context. Ultra-compact dwarfs (UCDs) are stellar systems displaying colours and metallicities between those of globular clusters (GCs) and early-type dwarf galaxies, as well as sizes of Reff 100 pc and luminosities in the range-13.5 <MV<-11 mag. Although their origin is still subject o...

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Autor principal:	De Rossi, Maria Emilia
Publicado:	2017
Materias:	Galaxies: elliptical and lenticular, cD Galaxies: photometry Galaxies: star clusters: general Astrophysics Luminance Spectroscopic analysis Stars Elliptical galaxies Galaxies: elliptical and lenticular , CD Galaxies: star clusters: generals Globular clusters Radial velocity Spectral fitting Stellar populations Galaxies
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00046361_v599_n_p_Faifer http://hdl.handle.net/20.500.12110/paper_00046361_v599_n_p_Faifer
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_00046361_v599_n_p_Faifer
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spelling	paper:paper_00046361_v599_n_p_Faifer2023-06-08T14:28:18Z First confirmed ultra-compact dwarf galaxy in the NGC 5044 group De Rossi, Maria Emilia Galaxies: elliptical and lenticular, cD Galaxies: photometry Galaxies: star clusters: general Astrophysics Luminance Spectroscopic analysis Stars Elliptical galaxies Galaxies: elliptical and lenticular , CD Galaxies: photometry Galaxies: star clusters: generals Globular clusters Radial velocity Spectral fitting Stellar populations Galaxies Context. Ultra-compact dwarfs (UCDs) are stellar systems displaying colours and metallicities between those of globular clusters (GCs) and early-type dwarf galaxies, as well as sizes of Reff 100 pc and luminosities in the range-13.5 <MV<-11 mag. Although their origin is still subject of debate, the most popular scenarios suggest that they are massive star clusters or the nuclei of tidally stripped dwarf galaxies. Aims. NGC 5044 is the central massive elliptical galaxy of the NGC 5044 group. Its GC/UCD system is completely unexplored. Methods. In Gemini+GMOS deep images of several fields around NGC 5044 and in spectroscopic multi-object data of one of these fields, we detected an unresolved source with g′ ∼ 20.6 mag, compatible with being an UCD. Its radial velocity was obtained with FXCOR and the penalized pixel-fitting (pPXF) code. To study its stellar population content, we measured the Lick/IDS indices and compared them with predictions of single stellar population models, and we used the full spectral fitting technique. Results. The spectroscopic analysis of the UCD revealed a radial velocity that agrees with the velocity of the elliptical galaxy NGC 5044. From the Lick/IDS indices, we have obtained a luminosity-weighted age and metallicity of 11.7+ 1.4 -1.2 Gyr and [Z/H] =-0.79 ± 0.04 dex, respectively, as well as [α/Fe] = 0.30 ± 0.06. From the full spectral fitting technique, we measured a lower age (8.52 Gyr) and a similar total metallicity ([Z/H] =-0.86 dex). Conclusions. Our results indicate that NGC 5044-UCD1 is most likely an extreme GC (MV ∼-12.5 mag) belonging to the GC system of the elliptical galaxy NGC 5044. © 2017 ESO. Fil:De Rossi, M.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2017 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00046361_v599_n_p_Faifer http://hdl.handle.net/20.500.12110/paper_00046361_v599_n_p_Faifer
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Galaxies: elliptical and lenticular, cD Galaxies: photometry Galaxies: star clusters: general Astrophysics Luminance Spectroscopic analysis Stars Elliptical galaxies Galaxies: elliptical and lenticular , CD Galaxies: photometry Galaxies: star clusters: generals Globular clusters Radial velocity Spectral fitting Stellar populations Galaxies
spellingShingle	Galaxies: elliptical and lenticular, cD Galaxies: photometry Galaxies: star clusters: general Astrophysics Luminance Spectroscopic analysis Stars Elliptical galaxies Galaxies: elliptical and lenticular , CD Galaxies: photometry Galaxies: star clusters: generals Globular clusters Radial velocity Spectral fitting Stellar populations Galaxies De Rossi, Maria Emilia First confirmed ultra-compact dwarf galaxy in the NGC 5044 group
topic_facet	Galaxies: elliptical and lenticular, cD Galaxies: photometry Galaxies: star clusters: general Astrophysics Luminance Spectroscopic analysis Stars Elliptical galaxies Galaxies: elliptical and lenticular , CD Galaxies: photometry Galaxies: star clusters: generals Globular clusters Radial velocity Spectral fitting Stellar populations Galaxies
description	Context. Ultra-compact dwarfs (UCDs) are stellar systems displaying colours and metallicities between those of globular clusters (GCs) and early-type dwarf galaxies, as well as sizes of Reff 100 pc and luminosities in the range-13.5 <MV<-11 mag. Although their origin is still subject of debate, the most popular scenarios suggest that they are massive star clusters or the nuclei of tidally stripped dwarf galaxies. Aims. NGC 5044 is the central massive elliptical galaxy of the NGC 5044 group. Its GC/UCD system is completely unexplored. Methods. In Gemini+GMOS deep images of several fields around NGC 5044 and in spectroscopic multi-object data of one of these fields, we detected an unresolved source with g′ ∼ 20.6 mag, compatible with being an UCD. Its radial velocity was obtained with FXCOR and the penalized pixel-fitting (pPXF) code. To study its stellar population content, we measured the Lick/IDS indices and compared them with predictions of single stellar population models, and we used the full spectral fitting technique. Results. The spectroscopic analysis of the UCD revealed a radial velocity that agrees with the velocity of the elliptical galaxy NGC 5044. From the Lick/IDS indices, we have obtained a luminosity-weighted age and metallicity of 11.7+ 1.4 -1.2 Gyr and [Z/H] =-0.79 ± 0.04 dex, respectively, as well as [α/Fe] = 0.30 ± 0.06. From the full spectral fitting technique, we measured a lower age (8.52 Gyr) and a similar total metallicity ([Z/H] =-0.86 dex). Conclusions. Our results indicate that NGC 5044-UCD1 is most likely an extreme GC (MV ∼-12.5 mag) belonging to the GC system of the elliptical galaxy NGC 5044. © 2017 ESO.
author	De Rossi, Maria Emilia
author_facet	De Rossi, Maria Emilia
author_sort	De Rossi, Maria Emilia
title	First confirmed ultra-compact dwarf galaxy in the NGC 5044 group
title_short	First confirmed ultra-compact dwarf galaxy in the NGC 5044 group
title_full	First confirmed ultra-compact dwarf galaxy in the NGC 5044 group
title_fullStr	First confirmed ultra-compact dwarf galaxy in the NGC 5044 group
title_full_unstemmed	First confirmed ultra-compact dwarf galaxy in the NGC 5044 group
title_sort	first confirmed ultra-compact dwarf galaxy in the ngc 5044 group
publishDate	2017
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00046361_v599_n_p_Faifer http://hdl.handle.net/20.500.12110/paper_00046361_v599_n_p_Faifer
work_keys_str_mv	AT derossimariaemilia firstconfirmedultracompactdwarfgalaxyinthengc5044group
_version_	1768541730139799552

First confirmed ultra-compact dwarf galaxy in the NGC 5044 group

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