University of Oulu

Aku Venhola, Reynier Peletier, Eija Laurikainen, Heikki Salo, Enrichetta Iodice, Steffen Mieske, Michael Hilker, Carolin Wittmann, Maurizio Paolillo, Michele Cantiello, Joachim Janz, Marilena Spavone, Raffaele D’Abrusco, Glenn van de Ven, Nicola Napolitano, Gijs Verdoes Kleijn, Massimo Capaccioli, Aniello Grado, Edwin Valentijn, Jesús Falcón-Barroso and Luca Limatola; The Fornax Deep Survey (FDS) with VST - VI. Optical properties of the dwarf galaxies in the Fornax cluster; A&A, 625 (2019) A143;

The Fornax Deep Survey (FDS) with VST : VI. Optical properties of the dwarf galaxies in the Fornax cluster

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Author: Venhola, Aku1,2; Peletier, Reynier2; Laurikainen, Eija1;
Organizations: 1Astronomy Research Unit, University of Oulu, Pentti Kaiteran katu 1, 90014 Oulu, Finland
2Kapteyn Institute, University of Groningen, Landleven 12, 9747, AD Groningen, The Netherlands
3INAF – Astronomical Observatory of Capodimonte, Salita Moiariello 16, 80131 Naples, Italy
4European Southern Observatory, Alonso de Cordova 3107, Vitacura, Santiago, Chile
5European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany
6Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 12-14, 69120 Heidelberg, Germany
7University of Naples Federico II, C.U. Monte Sant’Angelo, Via Cinthia, 80126 Naples, Italy
8INAF Osservatorio Astronomico d’Abruzzo, Via Maggini, 64100 Teramo, Italy
9Finnish Centre of Astronomy with ESO (FINCA), University of Turku, Väisäläntie 20, 21500 Piikkiö, Finland
10Smithsonian Astrophysical Observatory, 60 Garden Street, 02138 Cambridge, MA, USA
11Department of Astrophysics, University of Vienna, Türkenschanzstrasse 17, 1180 Wien, Austria
12Instituto de Astrofisica de Canarias, C/ Via L’actea s/n, 38200 La Laguna, Spain
13Depto. Astrofisica, Universidad de La Laguna, C/ Via L’actea s/n, 38200 La Laguna, Spain
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 2.8 MB)
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Language: English
Published: EDP Sciences, 2019
Publish Date: 2020-03-19


Context: Dwarf galaxies are the most common type of galaxies in galaxy clusters. Due to their low mass, they are more vulnerable to environmental effects than massive galaxies, and are thus optimal for studying the effects of the environment on galaxy evolution. By comparing the properties of dwarf galaxies with different masses, morphological types, and cluster-centric distances we can obtain information about the physical processes in clusters that play a role in the evolution of these objects and shape their properties. The Fornax Deep Survey Dwarf galaxy Catalog (FDSDC) includes 564 dwarf galaxies in the Fornax cluster and the in-falling Fornax A subgroup. This sample allows us to perform a robust statistical analysis of the structural and stellar population differences in the range of galactic environments within the Fornax cluster.

Aims: By comparing our results with works concerning other clusters and the theoretical knowledge of the environmental processes taking place in galaxy clusters, we aim to understand the main mechanisms transforming galaxies in the Fornax cluster.

Methods: We have exploited the FDSDC to study how the number density of galaxies, galaxy colors and structure change as a function of the cluster-centric distance, used as a proxy for the galactic environment and in-fall time. We also used deprojection methods to transform the observed shape and density distributions of the galaxies into the intrinsic physical values. These measurements are then compared with predictions of simple theoretical models of the effects of harassment and ram pressure stripping on galaxy structure. We used stellar population models to estimate the stellar masses, metallicities and ages of the dwarf galaxies. We compared the properties of the dwarf galaxies in Fornax with those in the other galaxy clusters with different masses.

Results: We present the standard scaling relations for dwarf galaxies, which are the size-luminosity, Sérsic n-magnitude and color-magnitude relations. New in this paper is that we find a different behavior for the bright dwarfs (−18.5 mag < Mr′ <  −16 mag) as compared to the fainter ones (Mr′ gt  −16 mag): While considering galaxies in the same magnitude-bins, we find that, while for fainter dwarfs the g′−r′ color is redder for lower surface brightness objects (as expected from fading stellar populations), for brighter dwarfs the color is redder for the higher surface brightness and higher Sérsic n objects. The trend of the bright dwarfs might be explained by those galaxies being affected by harassment and by slower quenching of star formation in their inner parts. As the fraction of early-type dwarfs with respect to late-types increases toward the central parts of the cluster, the color-surface brightness trends are also manifested in the cluster-centric trends, confirming that it is indeed the environment that changes the galaxies. We also estimate the strength of the ram-pressure stripping, tidal disruption, and harassment in the Fornax cluster, and find that our observations are consistent with the theoretically expected ranges of galaxy properties where each of those mechanisms dominate. We furthermore find that the luminosity function, color–magnitude relation, and axis-ratio distribution of the dwarfs in the center of the Fornax cluster are similar to those in the center of the Virgo cluster. This indicates that in spite of the fact that the Virgo is six times more massive, their central dwarf galaxy populations appear similar in the relations studied by us.

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Series: Astronomy and astrophysics
ISSN: 0004-6361
ISSN-E: 1432-0746
ISSN-L: 0004-6361
Volume: 625
Article number: A143
DOI: 10.1051/0004-6361/201935231
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: A.V. would like to thank the Vilho, Yrjö, and Kalle Väisälä Foundation of the Finnish Academy of Sci-ence and Letters for the financial support during the writing of this paper. GvdV acknowledges funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program under grant agreement No 724857 (Consolidator Grant ArcheoDyn). R.F.P., T.L., E.L., H.S.,E.I., and J.J. acknowledge financial support from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No. 721463 to the SUNDIAL ITN network. H.S., E.L., and A.V. are also supported by the Academy of Finland grant n:o 297738. C.W. is supported by the Deutsche Forschungs gemeinschaft (DFG, German Research Foundation) through project 394551440. J.F-B acknowledges support from grantAYA2016-77237-C3-1-P from the Spanish Ministry of Economy and Competitiveness (MINECO).
EU Grant Number: (721463) SUNDIAL - SUrvey Network for Deep Imaging Analysis and Learning
Academy of Finland Grant Number: 297738
Detailed Information: 297738 (Academy of Finland Funding decision)
Copyright information: © ESO 2019.