Stellar systems in the direction of Pegasus I : I. Low surface brightness galaxies

Autores
González, Nélida Mabel; Smith Castelli, Analía Viviana; Faifer, Favio Raúl; Escudero, Carlos Gabriel; Cellone, Sergio Aldo
Año de publicación
2018
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Context. In spite of the numerous studies of low-luminosity galaxies in different environments, there is still no consensus about their formation scenario. In particular, a large number of galaxies displaying extremely low surface brightnesses have been detected in recent years and the nature of these objects is still under discussion. Aims. In order to enlarge the sample of known low-surface-brightness (LSB) galaxies and to try to provide clues about their nature, we report the detection of eight such objects (μ eff,g′ â 27 mag arcsec -2 ) towards the group of galaxies Pegasus I. They are located, in projection, within a radius of ∼200 kpc in the very center of Pegasus I, close to the dominant elliptical galaxies NGC 7619 and NGC 7626. Methods. We analyzed deep, high-quality GEMINI-GMOS images with ELLIPSE within IRAF in order to obtain their brightness profiles and structural parameters. We also fit Sérsic functions to these profiles in order to compare their properties with those of typical early-Type galaxies. Results. Assuming that these galaxies are at the distance of Pegasus I, we have found that their sizes are intermediate among similar objects reported in the literature. In particular, we found that three of these galaxies can be classified as ultra-diffuse galaxies and a fourth one displays a nucleus. The eight new LSB galaxies show significant color dispersion around the extrapolation towards faint luminosities of the color-magnitude relation defined by typical early-Type galaxies. In addition, they display values of the Sérsic index below 1 (concave brightness profiles in linear scale), in agreement with values obtained for LSB galaxies in other environments. Conclusions. We show that there seems to be a bias effect in the size distributions of the detected LSBs in different environments, in the sense that more distant groups/clusters lack small r eff objects, while large systems are not found in the Local Group and nearby environments. While there may be an actual shortage of large LSB galaxies in low-density environments like the Local Group, the non-detection of small (and faint) systems at large distances is clearly a selection effect. As an example, LSB galaxies with similar sizes to those of the satellites of Andromeda in the Local Group will be certainly missed in a visual identification at the distance of Pegasus I.
Instituto de Astrofísica de La Plata
Facultad de Ciencias Astronómicas y Geofísicas
Materia
Astronomía
Methods: observational
Techniques: photometric
Galaxies: groups: individual: Pegasus I
Galaxies: star clusters: general
Galaxies: dwarf
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by-nc-sa/4.0/
Repositorio
SEDICI (UNLP)
Institución
Universidad Nacional de La Plata
OAI Identificador
oai:sedici.unlp.edu.ar:10915/94044

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oai_identifier_str oai:sedici.unlp.edu.ar:10915/94044
network_acronym_str SEDICI
repository_id_str 1329
network_name_str SEDICI (UNLP)
spelling Stellar systems in the direction of Pegasus I : I. Low surface brightness galaxiesGonzález, Nélida MabelSmith Castelli, Analía VivianaFaifer, Favio RaúlEscudero, Carlos GabrielCellone, Sergio AldoAstronomíaMethods: observationalTechniques: photometricGalaxies: groups: individual: Pegasus IGalaxies: star clusters: generalGalaxies: dwarfContext. In spite of the numerous studies of low-luminosity galaxies in different environments, there is still no consensus about their formation scenario. In particular, a large number of galaxies displaying extremely low surface brightnesses have been detected in recent years and the nature of these objects is still under discussion. Aims. In order to enlarge the sample of known low-surface-brightness (LSB) galaxies and to try to provide clues about their nature, we report the detection of eight such objects (μ eff,g′ â 27 mag arcsec -2 ) towards the group of galaxies Pegasus I. They are located, in projection, within a radius of ∼200 kpc in the very center of Pegasus I, close to the dominant elliptical galaxies NGC 7619 and NGC 7626. Methods. We analyzed deep, high-quality GEMINI-GMOS images with ELLIPSE within IRAF in order to obtain their brightness profiles and structural parameters. We also fit Sérsic functions to these profiles in order to compare their properties with those of typical early-Type galaxies. Results. Assuming that these galaxies are at the distance of Pegasus I, we have found that their sizes are intermediate among similar objects reported in the literature. In particular, we found that three of these galaxies can be classified as ultra-diffuse galaxies and a fourth one displays a nucleus. The eight new LSB galaxies show significant color dispersion around the extrapolation towards faint luminosities of the color-magnitude relation defined by typical early-Type galaxies. In addition, they display values of the Sérsic index below 1 (concave brightness profiles in linear scale), in agreement with values obtained for LSB galaxies in other environments. Conclusions. We show that there seems to be a bias effect in the size distributions of the detected LSBs in different environments, in the sense that more distant groups/clusters lack small r eff objects, while large systems are not found in the Local Group and nearby environments. While there may be an actual shortage of large LSB galaxies in low-density environments like the Local Group, the non-detection of small (and faint) systems at large distances is clearly a selection effect. As an example, LSB galaxies with similar sizes to those of the satellites of Andromeda in the Local Group will be certainly missed in a visual identification at the distance of Pegasus I.Instituto de Astrofísica de La PlataFacultad de Ciencias Astronómicas y Geofísicas2018-12-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf1-15http://sedici.unlp.edu.ar/handle/10915/94044enginfo:eu-repo/semantics/altIdentifier/url/https://www.aanda.org/10.1051/0004-6361/201834172info:eu-repo/semantics/altIdentifier/issn/0004-6361info:eu-repo/semantics/altIdentifier/hdl/11336/86565info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201834172info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by-nc-sa/4.0/Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-10-22T17:00:16Zoai:sedici.unlp.edu.ar:10915/94044Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-10-22 17:00:16.758SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Stellar systems in the direction of Pegasus I : I. Low surface brightness galaxies
title Stellar systems in the direction of Pegasus I : I. Low surface brightness galaxies
spellingShingle Stellar systems in the direction of Pegasus I : I. Low surface brightness galaxies
González, Nélida Mabel
Astronomía
Methods: observational
Techniques: photometric
Galaxies: groups: individual: Pegasus I
Galaxies: star clusters: general
Galaxies: dwarf
title_short Stellar systems in the direction of Pegasus I : I. Low surface brightness galaxies
title_full Stellar systems in the direction of Pegasus I : I. Low surface brightness galaxies
title_fullStr Stellar systems in the direction of Pegasus I : I. Low surface brightness galaxies
title_full_unstemmed Stellar systems in the direction of Pegasus I : I. Low surface brightness galaxies
title_sort Stellar systems in the direction of Pegasus I : I. Low surface brightness galaxies
dc.creator.none.fl_str_mv González, Nélida Mabel
Smith Castelli, Analía Viviana
Faifer, Favio Raúl
Escudero, Carlos Gabriel
Cellone, Sergio Aldo
author González, Nélida Mabel
author_facet González, Nélida Mabel
Smith Castelli, Analía Viviana
Faifer, Favio Raúl
Escudero, Carlos Gabriel
Cellone, Sergio Aldo
author_role author
author2 Smith Castelli, Analía Viviana
Faifer, Favio Raúl
Escudero, Carlos Gabriel
Cellone, Sergio Aldo
author2_role author
author
author
author
dc.subject.none.fl_str_mv Astronomía
Methods: observational
Techniques: photometric
Galaxies: groups: individual: Pegasus I
Galaxies: star clusters: general
Galaxies: dwarf
topic Astronomía
Methods: observational
Techniques: photometric
Galaxies: groups: individual: Pegasus I
Galaxies: star clusters: general
Galaxies: dwarf
dc.description.none.fl_txt_mv Context. In spite of the numerous studies of low-luminosity galaxies in different environments, there is still no consensus about their formation scenario. In particular, a large number of galaxies displaying extremely low surface brightnesses have been detected in recent years and the nature of these objects is still under discussion. Aims. In order to enlarge the sample of known low-surface-brightness (LSB) galaxies and to try to provide clues about their nature, we report the detection of eight such objects (μ eff,g′ â 27 mag arcsec -2 ) towards the group of galaxies Pegasus I. They are located, in projection, within a radius of ∼200 kpc in the very center of Pegasus I, close to the dominant elliptical galaxies NGC 7619 and NGC 7626. Methods. We analyzed deep, high-quality GEMINI-GMOS images with ELLIPSE within IRAF in order to obtain their brightness profiles and structural parameters. We also fit Sérsic functions to these profiles in order to compare their properties with those of typical early-Type galaxies. Results. Assuming that these galaxies are at the distance of Pegasus I, we have found that their sizes are intermediate among similar objects reported in the literature. In particular, we found that three of these galaxies can be classified as ultra-diffuse galaxies and a fourth one displays a nucleus. The eight new LSB galaxies show significant color dispersion around the extrapolation towards faint luminosities of the color-magnitude relation defined by typical early-Type galaxies. In addition, they display values of the Sérsic index below 1 (concave brightness profiles in linear scale), in agreement with values obtained for LSB galaxies in other environments. Conclusions. We show that there seems to be a bias effect in the size distributions of the detected LSBs in different environments, in the sense that more distant groups/clusters lack small r eff objects, while large systems are not found in the Local Group and nearby environments. While there may be an actual shortage of large LSB galaxies in low-density environments like the Local Group, the non-detection of small (and faint) systems at large distances is clearly a selection effect. As an example, LSB galaxies with similar sizes to those of the satellites of Andromeda in the Local Group will be certainly missed in a visual identification at the distance of Pegasus I.
Instituto de Astrofísica de La Plata
Facultad de Ciencias Astronómicas y Geofísicas
description Context. In spite of the numerous studies of low-luminosity galaxies in different environments, there is still no consensus about their formation scenario. In particular, a large number of galaxies displaying extremely low surface brightnesses have been detected in recent years and the nature of these objects is still under discussion. Aims. In order to enlarge the sample of known low-surface-brightness (LSB) galaxies and to try to provide clues about their nature, we report the detection of eight such objects (μ eff,g′ â 27 mag arcsec -2 ) towards the group of galaxies Pegasus I. They are located, in projection, within a radius of ∼200 kpc in the very center of Pegasus I, close to the dominant elliptical galaxies NGC 7619 and NGC 7626. Methods. We analyzed deep, high-quality GEMINI-GMOS images with ELLIPSE within IRAF in order to obtain their brightness profiles and structural parameters. We also fit Sérsic functions to these profiles in order to compare their properties with those of typical early-Type galaxies. Results. Assuming that these galaxies are at the distance of Pegasus I, we have found that their sizes are intermediate among similar objects reported in the literature. In particular, we found that three of these galaxies can be classified as ultra-diffuse galaxies and a fourth one displays a nucleus. The eight new LSB galaxies show significant color dispersion around the extrapolation towards faint luminosities of the color-magnitude relation defined by typical early-Type galaxies. In addition, they display values of the Sérsic index below 1 (concave brightness profiles in linear scale), in agreement with values obtained for LSB galaxies in other environments. Conclusions. We show that there seems to be a bias effect in the size distributions of the detected LSBs in different environments, in the sense that more distant groups/clusters lack small r eff objects, while large systems are not found in the Local Group and nearby environments. While there may be an actual shortage of large LSB galaxies in low-density environments like the Local Group, the non-detection of small (and faint) systems at large distances is clearly a selection effect. As an example, LSB galaxies with similar sizes to those of the satellites of Andromeda in the Local Group will be certainly missed in a visual identification at the distance of Pegasus I.
publishDate 2018
dc.date.none.fl_str_mv 2018-12-01
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
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format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://sedici.unlp.edu.ar/handle/10915/94044
url http://sedici.unlp.edu.ar/handle/10915/94044
dc.language.none.fl_str_mv eng
language eng
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info:eu-repo/semantics/altIdentifier/issn/0004-6361
info:eu-repo/semantics/altIdentifier/hdl/11336/86565
info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201834172
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
eu_rights_str_mv openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
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