Bibcode
Venhola, Aku; Peletier, Reynier; Laurikainen, Eija; Salo, Heikki; Iodice, Enrichetta; Mieske, Steffen; Hilker, Michael; Wittmann, Carolin; Paolillo, Maurizio; Cantiello, Michele; Janz, Joachim; Spavone, Marilena; D'Abrusco, Raffaele; van de Ven, Glenn; Napolitano, Nicola; Verdoes Kleijn, Gijs; Capaccioli, Massimo; Grado, Aniello; Valentijn, Edwin; Falcón-Barroso, Jesús; Limatola, Luca
Bibliographical reference
Astronomy and Astrophysics, Volume 625, id.A143, 26 pp.
Advertised on:
5
2019
Journal
Citations
56
Refereed citations
52
Description
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' > -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.
Related projects
Traces of Galaxy Formation: Stellar populations, Dynamics and Morphology
We are a large, diverse, and very active research group aiming to provide a comprehensive picture for the formation of galaxies in the Universe. Rooted in detailed stellar population analysis, we are constantly exploring and developing new tools and ideas to understand how galaxies came to be what we now observe.
Ignacio
Martín Navarro