How Young are Early-type Cluster Galaxies? Quantifying the Young Stellar Component in a Rich Cluster at [FORMULA][F]z=0.41[/F][/FORMULA]

2000 ◽  
Vol 541 (2) ◽  
pp. L37-L40 ◽  
Author(s):  
Ignacio Ferreras ◽  
Joseph Silk
2020 ◽  
Vol 500 (1) ◽  
pp. 1323-1339
Author(s):  
Ciria Lima-Dias ◽  
Antonela Monachesi ◽  
Sergio Torres-Flores ◽  
Arianna Cortesi ◽  
Daniel Hernández-Lang ◽  
...  

ABSTRACT The nearby Hydra cluster (∼50 Mpc) is an ideal laboratory to understand, in detail, the influence of the environment on the morphology and quenching of galaxies in dense environments. We study the Hydra cluster galaxies in the inner regions (1R200) of the cluster using data from the Southern Photometric Local Universe Survey, which uses 12 narrow and broad-band filters in the visible region of the spectrum. We analyse structural (Sérsic index, effective radius) and physical (colours, stellar masses, and star formation rates) properties. Based on this analysis, we find that ∼88 per cent of the Hydra cluster galaxies are quenched. Using the Dressler–Schectman test approach, we also find that the cluster shows possible substructures. Our analysis of the phase-space diagram together with density-based spatial clustering algorithm indicates that Hydra shows an additional substructure that appears to be in front of the cluster centre, which is still falling into it. Our results, thus, suggest that the Hydra cluster might not be relaxed. We analyse the median Sérsic index as a function of wavelength and find that for red [(u − r) ≥2.3] and early-type galaxies it displays a slight increase towards redder filters (13 and 18 per cent, for red and early type, respectively), whereas for blue + green [(u − r)<2.3] galaxies it remains constant. Late-type galaxies show a small decrease of the median Sérsic index towards redder filters. Also, the Sérsic index of galaxies, and thus their structural properties, do not significantly vary as a function of clustercentric distance and density within the cluster; and this is the case regardless of the filter.


1998 ◽  
Vol 499 (2) ◽  
pp. 600-607 ◽  
Author(s):  
Priyamvada Natarajan ◽  
Jean‐Paul Kneib ◽  
Ian Smail ◽  
Richard S. Ellis

1996 ◽  
Vol 171 ◽  
pp. 233-240 ◽  
Author(s):  
Marijn Franx ◽  
Pieter G. van Dokkum

The existence of the Fundamental Plane of early-type galaxies implies that the M/L ratios of early-types are well behaved. It provides therefore an important tool to measure the evolution of the M/L ratio with redshift. These measurements, in combination with measurements of the evolution of the luminosity function, can be used to constrain the mass evolution of galaxies.We present the Fundamental Plane relation measured for galaxies in the rich cluster CL 0024+16 at z=0.391. The galaxies satisfy a tight Fundamental Plane, with relatively low scatter (15 %). The M/L is 31 ± 12 % lower than the M/L measured in Coma, which is consistent with simple evolutionary models. Hence, galaxies with very similar dynamical properties existed at a z=0.4.More, and deeper data are needed to measure the evolution of the slope and the scatter of the Fundamental Plane to higher accuracy. Furthermore, data on the richest nearby clusters would be valuable to test the hypothesis that the Fundamental Plane is independent of cluster environment.


2014 ◽  
Vol 797 (2) ◽  
pp. 136 ◽  
Author(s):  
Anna Ferré-Mateu ◽  
Patricia Sánchez-Blázquez ◽  
Alexandre Vazdekis ◽  
Ignacio G. de la Rosa

Author(s):  
Silvia Pellegrini ◽  
Andrea Negri ◽  
Luca Ciotti

AbstractEarly-type galaxies (ETGs) host a hot ISM produced mainly by stellar winds, and heated by Type Ia supernovae and the thermalization of stellar motions. High resolution 2D hydrodynamical simulations showed that ordered rotation in the stellar component results in the formation of a centrifugally supported cold equatorial disc. In a recent numerical investigation we found that subsequent generations of stars are formed in this cold disc; this process consumes most of the cold gas, leaving at the present epoch cold masses comparable to those observed. Most of the new stellar mass formed a few Gyrs ago, and resides in a disc.


2018 ◽  
Vol 611 ◽  
pp. A42 ◽  
Author(s):  
S. Boissier ◽  
O. Cucciati ◽  
A. Boselli ◽  
S. Mei ◽  
L. Ferrarese

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.


2009 ◽  
Vol 5 (S262) ◽  
pp. 85-88
Author(s):  
Esther Mármol-Queraltó ◽  
Nicolás Cardiel ◽  
P. Sánchez-Blázquez ◽  
S. C. Trager ◽  
R. F. Peletier ◽  
...  

AbstractA full understanding of the physical properties of integrated stellar systems demands a multiwavelength approach since each spectral window shows us the contribution of different types of stars. However, most of the observational effort in stellar population studies has been focused on the optical range. Now, the new generation of instruments allow us to explore the K band, where RGB and AGB stars dominate the light of the integrated spectra. Here we present a K-band spectroscopic analysis of early-type galaxies in different environments. Our sample comprises 12 field early-type galaxies observed with ISAAC at VLT with medium resolution, and they are compared with 11 Fornax cluster galaxies previously reported by Silva et al. (2008). The clear differences found in the infrared DCO and NaI indices between field and Fornax galaxies are discussed, trying to solve the puzzle formed by the near-infrared and optical measurements.


2008 ◽  
Vol 389 (4) ◽  
pp. 1891-1904 ◽  
Author(s):  
T. D. Rawle ◽  
Russell J. Smith ◽  
J. R. Lucey ◽  
A. M. Swinbank

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