Evolution of the UV upturn in cluster galaxies: Abell 1689

Context. At low redshift, early-type galaxies often exhibit a rising flux with decreasing wavelength in the 1000–2500 Å range, called “UV upturn”. The origin of this phenomenon is debated, and its evolution with redshift is poorly constrained. The observed GALEX FUV-NUV color can be used to probe the UV upturn approximately to redshift 0.5.Aim. We provide constraints on the existence of the UV upturn up to redshift ~0.4 in the brightest cluster galaxies (BCG) located behind the Virgo cluster, using data from the GUViCS survey.Methods. We estimate the GALEX far-UV (FUV) and near-UV (NUV) observed magnitudes for BCGs from the maxBCG catalog in the GUViCS fields. We increase the number of nonlocal galaxies identified as BCGs with GALEX photometry from a few tens of galaxies to 166 (64 when restricting this sample to relatively small error bars). We also estimate a central color within a 20 arcsec aperture. By using the r-band luminosity from the maxBCG catalog, we can separate blue FUV-NUV due to recent star formation and candidate upturn cases. We use Lick indices to verify their similarity to redshift 0 upturn cases.Results. We clearly detect a population of blue FUV-NUV BCGs in the redshift range 0.10–0.35, vastly improving the existing constraints at these epochs by increasing the number of galaxies studied, and by exploring a redshift range with no previous data (beyond 0.2), spanning one more Gyr in the past. These galaxies bring new constraints that can help distinguish between assumptions concerning the stellar populations causing the UV upturn phenomenon. The existence of a large number of UV upturns around redshift 0.25 favors the existence of a binary channel among the sources proposed in the literature.

Download Full-text

The UV-upturn in brightest cluster galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921314004888 ◽

2012 ◽

Vol 10 (H16) ◽

pp. 127-127

Author(s):

S. I. Loubser ◽

P. Sánchez-Blázquez

Keyword(s):

Stellar Population ◽

Control Sample ◽

Mass Range ◽

High Signal ◽

Signal To Noise ◽

Cluster Galaxies ◽

Colour Measurements ◽

Brightest Cluster Galaxies ◽

Sedimentation Model ◽

Uv Upturn

AbstractThis study is part of a series devoted to the investigation of a large sample of brightest cluster galaxies (BCGs), their properties and the relationships between these and the properties of the host clusters. In this paper, we compare the stellar population properties derived from high signal-to-noise, optical long-slit spectra with the GALEX ultraviolet (UV) colour measurements for 36 nearby BCGs to understand the diversity in the most rapidly evolving feature in old stellar systems, the UV-upturn. We investigate: (1) the possible differences between the UV-upturn of BCGs and those of a control sample of ordinary ellipticals in the same mass range, as well as possible correlations between the UV-upturn and other general properties of the galaxies; (2) possible correlations between the UV-upturn and the properties of the host clusters; (3) recently proposed scenarios where helium-sedimentation in the cluster centre can produce an enhanced UV-upturn. We find systematic differences between the UV-colours of BCGs and ordinary ellipticals, but we do not find correlations between these colours and the properties of the host clusters. Furthermore, the observations do not support the predictions made by the helium-sedimentation model as an enhancer of the UV-upturn.

Download Full-text

Environmental effects on the UV upturn in local clusters of galaxies

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1502 ◽

2019 ◽

Vol 487 (3) ◽

pp. 3021-3028 ◽

Cited By ~ 1

Author(s):

Sadman S Ali ◽

Malcolm N Bremer ◽

Steven Phillipps ◽

Roberto De Propris

Keyword(s):

Early Type ◽

Cluster Galaxies ◽

Cluster Environment ◽

On Line ◽

Cluster Properties ◽

Projected Position ◽

Far Ultraviolet ◽

Uv Upturn ◽

Intrinsic Feature ◽

Infrared Data

ABSTRACT We explore the dependence of ultraviolet (UV) upturn colours in early-type cluster galaxies on the properties of their parent clusters (such as velocity dispersion and X-ray luminosity) and on the positions and kinematics of galaxies within them. We use a sample of 24 nearby clusters with highly complete spectroscopy and optical/infrared data to select a suitable sample of red-sequence galaxies, whose far-ultraviolet and NUV magnitudes we measure from archival GALEX data. Our results show that the UV upturn colour has no dependence on cluster properties and has the same range in all clusters. There is also no dependence on the projected position within clusters or on line-of-sight velocity. Therefore, our conclusion is that the UV upturn phenomenon is an intrinsic feature of cluster early-type galaxies, irrespective of their cluster environment.

Download Full-text

Galaxy And Mass Assembly (GAMA): Defining passive galaxy samples and searching for the UV upturn

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz3552 ◽

2019 ◽

Vol 492 (2) ◽

pp. 2128-2139

Author(s):

S Phillipps ◽

S S Ali ◽

M N Bremer ◽

R De Propris ◽

A E Sansom ◽

...

Keyword(s):

Star Formation ◽

Cluster Galaxies ◽

Star Forming ◽

Stellar Component ◽

Wide Range ◽

Other Information ◽

Mass Assembly ◽

Clean Sample ◽

Uv Upturn ◽

Red Sequence

ABSTRACT We use data from the GAMA and GALEX surveys to demonstrate that the UV upturn, an unexpected excess of ultraviolet flux from a hot stellar component, seen in the spectra of many early-type galaxies, arises from processes internal to individual galaxies with no measurable influence from the galaxies’ larger environment. We first define a clean sample of passive galaxies without a significant contribution to their UV flux from low-level star formation. We confirm that galaxies with the optical colours of red sequence galaxies often have signs of residual star formation, which, without other information, would prevent a convincing demonstration of the presence of UV upturns. However, by including (NUV−u) and WISE (W2–W3) colours, and FUV data where it exists, we can convincingly constrain samples to be composed of non-star-forming objects. Using such a sample, we examine GALEX photometry of low-redshift GAMA galaxies in a range of low-density environments, from groups to the general field, searching for UV upturns. We find a wide range of (NUV−r) colours, entirely consistent with the range seen – and attributed to the UV upturn – in low-redshift red sequence cluster galaxies. The range of colours is independent of group multiplicity or velocity dispersion, with isolated passive galaxies just as likely to have blue UV-to-optical colours, implying significant upturn components, as those in richer groups and in the previous data on clusters. This is supported by equivalent results for (FUV−r) colours which are clear indicators of upturn components.

Download Full-text

UV SEDs of early-type cluster galaxies: a new look at the UV upturn

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/sty227 ◽

2018 ◽

Vol 476 (1) ◽

pp. 1010-1020 ◽

Cited By ~ 8

Author(s):

S S Ali ◽

M N Bremer ◽

S Phillipps ◽

R De Propris

Keyword(s):

Early Type ◽

Cluster Galaxies ◽

Uv Upturn ◽

New Look

Download Full-text

Brightest cluster galaxies: the centre can(not?) hold

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3286 ◽

2020 ◽

Vol 500 (1) ◽

pp. 310-318

Author(s):

Roberto De Propris ◽

Michael J West ◽

Felipe Andrade-Santos ◽

Cinthia Ragone-Figueroa ◽

Elena Rasia ◽

...

Keyword(s):

Dark Matter ◽

Local Environment ◽

Major Axis ◽

Theoretical Models ◽

Dark Matter Halo ◽

Gas Distribution ◽

X Ray ◽

Cluster Galaxies ◽

Peculiar Velocities ◽

Brightest Cluster Galaxies

ABSTRACT We explore the persistence of the alignment of brightest cluster galaxies (BCGs) with their local environment. We find that a significant fraction of BCGs do not coincide with the centroid of the X-ray gas distribution and/or show peculiar velocities (they are not at rest with respect to the cluster mean). Despite this, we find that BCGs are generally aligned with the cluster mass distribution even when they have significant offsets from the X-ray centre and significant peculiar velocities. The large offsets are not consistent with simple theoretical models. To account for these observations BCGs must undergo mergers preferentially along their major axis, the main infall direction. Such BCGs may be oscillating within the cluster potential after having been displaced by mergers or collisions, or the dark matter halo itself may not yet be relaxed.

Download Full-text

Excitation mechanism in the intracluster filaments surrounding the Brightest Cluster Galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921320002343 ◽

2019 ◽

Vol 15 (S359) ◽

pp. 185-187

Author(s):

Fiorella L. Polles

Keyword(s):

Active Galactic Nuclei ◽

Galactic Nuclei ◽

Elliptical Galaxies ◽

Cluster Galaxies ◽

Cooling Flow ◽

Submillimeter Wavelengths ◽

Hot Plasma ◽

Brightest Cluster Galaxies ◽

Multi Phase ◽

The Impact

AbstractMulti-phase filamentary structures surrounding giant elliptical galaxies at the center of cool-core clusters, the Brightest Cluster Galaxies (BCGs), have been detected from optical to submillimeter wavelengths. The source of the ionisation in the filaments is still debated. Studying the excitation of these structures is key to our understanding of Active Galactic Nuclei (AGN) feedback in general, and more precisely of the impact of environmental and local effects on star formation. One possible contributor to the excitation of the filaments is the thermal radiation from the cooling of the hot plasma surrounding the BCGs, the so-called cooling flow.

Download Full-text

A Precise Benchmark for Cluster Scaling Relations: Fundamental Plane, Mass Plane and IMF in the Coma Cluster from Dynamical Models

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1043 ◽

2020 ◽

Cited By ~ 2

Author(s):

Shravan Shetty ◽

Michele Cappellari ◽

Richard M McDermid ◽

Davor Krajnović ◽

P T de Zeeuw ◽

...

Keyword(s):

Galaxy Formation ◽

Scaling Relations ◽

Coma Cluster ◽

Dynamical Models ◽

Fundamental Plane ◽

Cluster Galaxies ◽

Dynamical Scaling ◽

Small Uncertainty ◽

Cluster Distance ◽

Using Data

Abstract We study a sample of 148 early-type galaxies in the Coma cluster using SDSS photometry and spectra, and calibrate our results using detailed dynamical models for a subset of these galaxies, to create a precise benchmark for dynamical scaling relations in high-density environments. For these galaxies, we successfully measured global galaxy properties, modeled stellar populations, and created dynamical models, and support the results using detailed dynamical models of 16 galaxies, including the two most massive cluster galaxies, using data taken with the SAURON IFU. By design, the study provides minimal scatter in derived scaling relations due to the small uncertainty in the relative distances of galaxies compared to the cluster distance. Our results demonstrate low (≤55% for 90th percentile) dark matter fractions in the inner 1Re of galaxies. Owing to the study design, we produce the tightest, to our knowledge, IMF-σe relation of galaxies, with a slope consistent with that seen in local galaxies. Leveraging our dynamical models, we transform the classical Fundamental Plane of the galaxies to the Mass Plane. We find that the coefficients of the mass plane are close to predictions from the virial theorem, and have significantly lower scatter compared to the Fundamental plane. We show that Coma galaxies occupy similar locations in the (M* - Re) and (M* - σe) relations as local field galaxies but are older. This, and the fact we find only three slow rotators in the cluster, is consistent with the scenario of hierarchical galaxy formation and expectations of the kinematic morphology-density relation.

Download Full-text

Radial gradients in initial mass function sensitive absorption features in the Coma brightest cluster galaxies

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stw2712 ◽

2016 ◽

Vol 465 (1) ◽

pp. 192-212 ◽

Cited By ~ 23

Author(s):

Simon Zieleniewski ◽

Ryan C. W. Houghton ◽

Niranjan Thatte ◽

Roger L. Davies ◽

Sam P. Vaughan

Keyword(s):

Mass Function ◽

Initial Mass Function ◽

Initial Mass ◽

Cluster Galaxies ◽

Brightest Cluster Galaxies ◽

Absorption Features

Download Full-text

The growth of the red-sequence in clusters since ≃1

Proceedings of the International Astronomical Union ◽

10.1017/s1743921310008410 ◽

2009 ◽

Vol 5 (H15) ◽

pp. 88-88

Author(s):

Roberto P. Muñoz ◽

L. F. Barrientos ◽

B. P. Koester ◽

D. G. Gilbank ◽

M. D. Gladders ◽

...

Keyword(s):

Star Formation ◽

Galaxy Clusters ◽

Evolutionary Model ◽

Large Ensemble ◽

Cluster Galaxies ◽

Nir Imaging ◽

Measured Change ◽

First Time ◽

The Universe ◽

Red Sequence

AbstractWe use deep nIR imaging of 15 galaxy clusters at z ≃ 1 to study the build-up of the red-sequence in rich clusters since the Universe was half its present age. We measured, for the first time, the luminous-to-faint ratio of red-sequence galaxies at z=1 from a large ensemble of clusters, and found an increase of 100% in the ratio of luminous-to-faint red-sequence galaxies from z=0.45 to 1.0. The measured change in this ratio as function of redshift is well-reproduced by a simple evolutionary model developed in this work, that consists in an early truncation of the star formation for bright cluster galaxies and a delayed truncation for faint cluster galaxies.

Download Full-text