The Herschel Virgo Cluster Survey

Boissier

Heinis

et al. 2011

A&A

Self Cite

The GALEX Ultraviolet Virgo Cluster Survey (GUViCS) is a complete blind survey of the Virgo cluster covering ∼40 sq. deg in the far UV (FUV, λ eff = 1539 Å, Δλ = 442 Å) and ∼120 sq. deg in the near UV (NUV, λ eff = 2316 Å, Δλ = 1060 Å). The goal of the survey is to study the ultraviolet (UV) properties of galaxies in a rich cluster environment, spanning a wide luminosity range from giants to dwarfs, and regardless of prior knowledge of their star formation activity. The UV data will be combined with those in other bands (optical: NGVS; far-infrared -submm: HeViCS; HI: ALFALFA) and with our multizone chemo-spectrophotometric models of galaxy evolution to make a complete and exhaustive study of the effects of the environment on the evolution of galaxies in high density regions. We present here the scientific objectives of the survey, describing the observing strategy and briefly discussing different data reduction techniques. Using UV data already in-hand for the central 12 sq. deg we determine the FUV and NUV luminosity functions of the Virgo cluster core for all cluster members and separately for early-and late-type galaxies and compare it to the one obtained in the field and other nearby clusters (Coma, A1367). This analysis shows that the FUV and NUV luminosity functions of the core of the Virgo clusters are flatter (α ∼ −1.1) than those determined in Coma and A1367. We discuss the possible origin of this difference.

Section: The Uv Luminosity Function Of the Central 12 Degmentioning

confidence: 97%

The GALEX Ultraviolet Virgo Cluster Survey (GUViCS)

Boissier

Heinis

et al. 2011

A&A

Self Cite

“…Fumagalli & Gavazzi 2008;Cortese et al 2010Cortese et al , 2012b. Some gas and dust can be retained in the nuclear regions, where the potential well is at its maximum, as indicated by high resolution Herschel images (de Looze et al 2010(de Looze et al , 2013. This happens mainly in the most massive dwarfs or in those objects located outside the X-ray emitting regions, where gas stripping is expected to be less efficient.…”

Section: Dwarf Galaxiesmentioning

confidence: 99%

The GALEX Ultraviolet Virgo Cluster Survey (GUViCS)

Voyer

Boissier

et al. 2014

A&A

Self Cite

153

254

We study the role of the environment on galaxy evolution using a sample of 868 galaxies in the Virgo cluster and in its surrounding regions that are selected from the GALEX Ultraviolet Virgo Cluster Survey (GUViCS) with the purpose of understanding the origin of the red sequence in dense environments. The sample spans a wide range in morphological types (from dwarf ellipticals to Im and BCD) and stellar masses (10 7 M star 10 11.5 M ). We collected multifrequency data covering the whole electromagnetic spectrum for most of the galaxies, including UV, optical, mid-and far-infrared imaging data, as well as optical and HI spectroscopic data. We first identify the different dynamical substructures that compose the Virgo cluster, and we calculate the local density of galaxies using different methods. We then study the distribution of galaxies belonging to the red sequence, the green valley, and the blue cloud within the different cluster substructures or as a function of galaxy density. Our analysis indicates that all the most massive galaxies (M star 10 11 M ) are slow rotators and are the dominant galaxies of the different cluster substructures, which are generally associated with a diffuse X-ray emission. They are probably the result of major merging events that occurred at early epochs, as also indicated by their very old stellar populations. Slow rotators of lower stellar mass (10 8.5M star 10 11 M ) are also preferentially located within the different high-density substructures of the cluster. Their position in the velocity space indicates that they are virialised within the cluster; thus, they are Virgo members since its formation. They have been shaped by gravitational perturbations occurring within the infalling groups that later form the cluster (pre-processing). On the contrary, low-mass star-forming systems are extremely rare in the inner regions of the Virgo cluster A, where the density of the intergalactic medium is at its maximum. Our ram pressure stripping models consistently indicate that these star-forming systems can be rapidly deprived of their interstellar medium during their interaction with the intergalactic medium. The lack of gas quenches their star-formation activity transforming them into quiescent dwarf ellipticals. This mild transformation does not perturb the kinematic properties of these galaxies, which still have rotation curves typical of star-forming systems.

“…Some gas retention, with the associated dust (de Looze et al 2010(de Looze et al , 2013, might be present in the core of the stripped galaxies where the gravitational potential well is at its maximum. This gas might feed star formation up to more recent epochs, and thus be at the origin of the blue centers observed in the most massive dwarf ellipticals ( ).…”

Section: The Virgo Clustermentioning

confidence: 99%

On the origin of the faint-end of the red sequence in high-density environments

Gavazzi

2014

Astron Astrophys Rev

155

125

With the advent of the next generation wide-field cameras it became possible to survey in an unbiased mode galaxies spanning a variety of local densities, from the core of rich clusters, to compact and loose groups, down to filaments and voids. The sensitivity reached by these instruments allowed to extend the observation to dwarf galaxies, the most "fragile" objects in the universe. At the same time models and simulations have been tailored to quantify the different effects of the environment on the evolution of galaxies. Simulations, models, and observations consistently indicate that star-forming dwarf galaxies entering high-density environments for the first time can be rapidly stripped from their interstellar medium. The lack of gas quenches the activity of star formation, producing on timescales of ∼1 Gyr quiescent galaxies with spectro-photometric, chemical, structural, and kinematical properties similar to those observed in dwarf early-type galaxies inhabiting rich clusters and loose groups. Simulations and observations consistently identify ram pressure stripping as the major effect responsible for the quenching of the star-formation activity in rich clusters. Gravitational interactions (galaxy harassment) can also be important in groups or in clusters whenever galaxies have been members since early epochs. The observation of clusters at different redshifts combined with the present high infalling rate of galaxies onto clusters indicate that the quenching of the star-formation activity in dwarf systems and the formation of the faint end of the red sequence is a very recent phenomenon.