The dwarf galaxy population in nearby clusters from the KIWICS survey

Choque-Challapa, Nelvy; Aguerri, J. A. L.; Piña, Pavel E. Mancera; Peletier, Reynier F.; Venhola, Aku; Verheijen, Marc

doi:10.1093/mnras/stab2420

“…The fraction in Fornax, estimated in a similar way is 0.15, hence in prefect agreement with that of Hydra I. In the Virgo cluster, the fraction of blue dwarfs is instead larger, ∼0.3 (Venhola et al 2019;Kim et al 2014;Choque-Challapa et al 2021). The similar dwarf fraction in Fornax and Hydra I clusters is intriguing, considering that Hydra I is more than twice as massive virial mass, and has a velocity dispersion almost two times higher (see Venhola et al 2018, and therein references for a summary of Fornax properties).…”

Section: Colors Of Hydra's Dwarf Galaxiessupporting

confidence: 80%

Galaxy populations in the Hydra I cluster from the VEGAS survey

Marca

¹

,

Peletier

²

,

Iodice

³

et al. 2022

A&A

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Context. Due to their relatively low stellar mass content and diffuse nature, the evolution of dwarf galaxies can be strongly affected by their environment. Analyzing the properties of the dwarf galaxies over a wide range of luminosities, sizes, morphological types, and environments, we can obtain insights about their evolution. At ∼50 Mpc, the Hydra I cluster of galaxies is among the closest cluster in the z ≃ 0 Universe, and an ideal environment to study dwarf galaxy properties in a cluster environment. Aims. We exploit deep imaging data of the Hydra I cluster to construct a new photometric catalog of dwarf galaxies in the cluster core, which is then used to derive properties of the Hydra I cluster dwarf galaxy population as well as to compare it with other clusters. Moreover, we investigate the dependency of dwarf galaxy properties on their surrounding environment. Methods. The new wide-field g- and r-band images of the Hydra I cluster obtained with the OmegaCAM camera on the VLT Survey Telescope (VST) in the context of the VST Early-type GAlaxy Survey (VEGAS) were used to study the dwarf galaxy population in the Hydra I cluster core down to r-band magnitude Mr = −11.5 mag. We used an automatic detection tool to identify dwarf galaxies from a ∼1 deg2 field centered on the Hydra I core, covering almost half of the cluster virial radius. The photometric pipeline was used to estimate the principal photometric parameters for all targets. Scaling relations and visual inspection were used to assess the cluster membership and construct a new dwarf galaxy catalog. Finally, based on the new catalog, we studied the structural (Sérsic index n, effective radius Re, and axis ratio) and photometric (colors and surface brightness) properties of the dwarf galaxies, also investigating how they vary as a function of clustercentric distance. Results. The new Hydra I dwarf catalog contains 317 galaxies with a luminosity between −18.5 < Mr < −11.5 mag, a semi-major axis larger than ∼200 pc (a = 0.84″), of which 202 are new detections, and previously unknown dwarf galaxies in the Hydra I central region. We estimate that our detection efficiency reaches 50% at the limiting magnitude Mr = −11.5 mag, and at the mean effective surface brightness μ̄e,r = 26.5 mag arcsec−2. We present the standard scaling relations for dwarf galaxies, which are color-magnitude, size-luminosity, and Sérsic n-magnitude relations, and compare them with other nearby clusters. We find that there are no observational differences for dwarfs scaling relations in clusters of different sizes. We study the spatial distribution of galaxies, finding evidence for the presence of substructures within half the virial radius. We also find that mid- and high-luminosity dwarfs (Mr < −14.5 mag) become, on average, redder toward the cluster center, and that they have a mild increase in Re with increasing clustercentric distance, similar to what is observed for the Fornax cluster. No clear clustercentric trends are reported for surface brightness and Sérsic index. Considering galaxies in the same magnitude bins, we find that for high and mid-luminosity dwarfs (Mr < −13.5 mag), the g − r color is redder for the brighter surface brightness and higher Sérsic n index objects. This finding is consistent with the effects of harassment and/or partial gas stripping.

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“…The analysis carried out in section 4.3 shows that the effective radii of the LSBGs in our sample have a clear dependence on the environment, in that LSBGs located close to NGC 1052 tend to be much larger. Previous works analyzing the correlation between effective radius and environment for LSBGs or dwarf galaxies show inconsistent results (Janz et al 2016;Román & Trujillo 2017a;Venhola et al 2019;Mancera Piña et al 2019;Choque-Challapa et al 2021;Kadowaki et al 2021). Even focusing on only those studies that find such a correlation, this correlation is very weak, with variations of only a small fraction of the average values of the effective radius across different environmental densities.…”

Section: Discussionmentioning

confidence: 94%

Discovery and analysis of low-surface-brightness galaxies in the environment of NGC 1052

Román

¹

,

Castilla

²

,

Pascual-Granado

³

2021

A&A

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The environment of NGC 1052 has recently attracted much attention because of the presence of low-surface-brightness galaxies (LSBGs) with apparently "exotic" properties, making it a region of high interest for the detection of new objects. We used public deep photometric data from the Dark Energy Camera Legacy Survey to carry out a comprehensive search for LSBGs over a wide region of 6×6 degrees, equivalent to 2×2 Mpc at the distance of NGC 1052. We detected 42 LSBGs with r e f f > 5 arcsec and µ g (0) > 24 mag arcsec −2 , of which 20 are previously undetected objects. Among all the newly detected objects, RCP 32 stands out with extreme properties: r e f f = 23.0 arcsec and <µ g > e f f = 28.6 mag arcsec −2 . This makes RCP 32 one of the lowest surface brightness galaxies ever detected through integrated photometry, located at just 10 arcmin from the extensively studied NGC 1052-DF2. We explored the presence of globular clusters (GCs) in the LSBGs. We marginally detected a GC system in RCP 32, and argue that this LSBG is of great interest for follow-up observations given its extremely low baryon density. After analyzing the distribution of galaxies with available spectroscopy, we identified a large-scale structure of approximately 1 Mpc that is well isolated in redshift space and centered on NGC 1052. The spatial correlation analysis between the LSBGs and this large-scale structure suggests their association. However, when exploring the distribution of effective radius, we find an overpopulation of large LSBGs (r e f f > 15 arcsec) located close to the line of sight of NGC 1052. We argue that this is suggestive of a substructure with similar radial velocity in sight projection, but at a closer distance, to which some of these apparently larger LSBGs could be associated. However. possible effects derived from tidal interactions are worthy of further study. Our work expands the catalog of LSBGs with new interesting objects and provides a detailed environmental context for the study of LSBGs in this region.

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“…The analysis carried out in section 4.3 shows that the effective radii of the LSBGs in our sample have a clear dependence on the environment, in that LSBGs located close to NGC 1052 tend to be much larger. Previous works analyzing the correlation between effective radius and environment for LSBGs or dwarf galaxies show inconsistent results (Janz et al 2016;Román & Trujillo 2017a;Venhola et al 2019;Mancera Piña et al 2019;Choque-Challapa et al 2021;Kadowaki et al 2021). Even focusing on only those studies that find such a correlation, this correlation is very weak, with variations of only a small fraction of the average values of the effective radius across different environmental densities.…”

Section: Discussionmentioning

confidence: 94%

Discovery and analysis of low-surface-brightness galaxies in the environment of NGC 1052

Román,

Castilla,

Pascual-Granado

2021

Preprint

0

View full text Add to dashboard Cite

The environment of NGC 1052 has recently attracted much attention because of the presence of low-surface-brightness galaxies (LSBGs) with apparently "exotic" properties, making it a region of high interest for the detection of new objects. We used public deep photometric data from the Dark Energy Camera Legacy Survey to carry out a comprehensive search for LSBGs over a wide region of 6×6 degrees, equivalent to 2×2 Mpc at the distance of NGC 1052. We detected 42 LSBGs with r e f f > 5 arcsec and µ g (0) > 24 mag arcsec −2 , of which 20 are previously undetected objects. Among all the newly detected objects, RCP 32 stands out with extreme properties: r e f f = 23.0 arcsec and <µ g > e f f = 28.6 mag arcsec −2 . This makes RCP 32 one of the lowest surface brightness galaxies ever detected through integrated photometry, located at just 10 arcmin from the extensively studied NGC 1052-DF2. We explored the presence of globular clusters (GCs) in the LSBGs. We marginally detected a GC system in RCP 32, and argue that this LSBG is of great interest for follow-up observations given its extremely low baryon density. After analyzing the distribution of galaxies with available spectroscopy, we identified a large-scale structure of approximately 1 Mpc that is well isolated in redshift space and centered on NGC 1052. The spatial correlation analysis between the LSBGs and this large-scale structure suggests their association. However, when exploring the distribution of effective radius, we find an overpopulation of large LSBGs (r e f f > 15 arcsec) located close to the line of sight of NGC 1052. We argue that this is suggestive of a substructure with similar radial velocity in sight projection, but at a closer distance, to which some of these apparently larger LSBGs could be associated. However. possible effects derived from tidal interactions are worthy of further study. Our work expands the catalog of LSBGs with new interesting objects and provides a detailed environmental context for the study of LSBGs in this region.

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The dwarf galaxy population in nearby clusters from the KIWICS survey

Cited by 5 publications

References 77 publications

Galaxy populations in the Hydra I cluster from the VEGAS survey

Galaxy populations in the Hydra I cluster from the VEGAS survey

Discovery and analysis of low-surface-brightness galaxies in the environment of NGC 1052

Discovery and analysis of low-surface-brightness galaxies in the environment of NGC 1052

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