scholarly journals The Epochs of Early-Type Galaxy Formation in Clusters and in the Field

Author(s):  
Daniel Thomas ◽  
Claudia Maraston ◽  
Ralf Bender
2014 ◽  
Vol 10 (S309) ◽  
pp. 291-292
Author(s):  
Ricardo Demarco ◽  
Alessandro Rettura ◽  
Chris Lidman ◽  
Julie Nantais ◽  
Yara Jaffe ◽  
...  

AbstractOne of the most characteristic features of galaxy clusters is the so-called “red sequence” (RS) of early-type galaxies. Since these galaxies are, in general, devoid of gas and dust, their red colors are mainly a consequence of their passive nature. However, the physical mechanisms responsible for quenching their star formation, thus originating the RS, are poorly understood. Environmental effects should play a significant role in the formation of the RS by transforming the observed galaxy properties from late to early-type ones. In this respect, we have initiated a KMOS program aimed at studying the kinematical structure of cluster galaxies at 0.8 < z < 1.7 in an effort to disentangle the physical mechanisms responsible for cluster galaxy evolution and the formation of the RS.


2002 ◽  
pp. 371-374
Author(s):  
Daniel Thomas ◽  
Claudia Maraston ◽  
Ralf Bender

2005 ◽  
Vol 621 (2) ◽  
pp. 673-694 ◽  
Author(s):  
Daniel Thomas ◽  
Claudia Maraston ◽  
Ralf Bender ◽  
Claudia Mendes de Oliveira

2019 ◽  
Vol 624 ◽  
pp. L6 ◽  
Author(s):  
Oliver Müller ◽  
R. Michael Rich ◽  
Javier Román ◽  
Mustafa K. Yıldız ◽  
Michal Bílek ◽  
...  

The possible existence of two dark-matter-free galaxies (NGC 1052-DF2 and NGC 1052-DF4) in the field of the early-type galaxy NGC 1052 presents a challenge to theories of dwarf galaxy formation according to the current cosmological paradigm. We carried out a search for signatures of past interactions connected to the putative hosts of NGC 1052-DF2 and NGC 1052-DF4 using a very deep L-band image obtained with the 0.7 m Jeanne Rich telescope that reach a surface brightness limit of 28.5 mag arcsec−2 in the r band. We found several low-surface brightness features, possibly consistent with an ongoing merger history in this group. We find a tidal interaction between NGC 1052 and NGC 1047, confirming a physical association. Furthermore, we find a stellar loop around NGC 1052 in the direction of NGC 1042 and a stellar stream pointing in the direction of NGC 1052-DF2, but they are not directly connected. We find no evidence for a recent tidal interaction for NGC 1052-DF2 and NGC 1052-DF4. No LSB features have been uncovered around the spiral galaxy NGC 1042, which leaves the association (physical or projected) between NGC 1052 and NGC 1042 ambiguous, although they have similar radial velocities. Their association will only be established when accurate distances to both objects have been measured.


2003 ◽  
Vol 597 (2) ◽  
pp. L117-L120 ◽  
Author(s):  
S. Khochfar ◽  
A. Burkert

1999 ◽  
Vol 514 (2) ◽  
pp. 844-855 ◽  
Author(s):  
A. Finoguenov ◽  
C. Jones ◽  
W. Forman ◽  
L. David

2021 ◽  
Vol 502 (1) ◽  
pp. 1487-1493
Author(s):  
Anton T Jaelani ◽  
Cristian E Rusu ◽  
Issha Kayo ◽  
Anupreeta More ◽  
Alessandro Sonnenfeld ◽  
...  

ABSTRACT We present spectroscopic confirmation of three new two-image gravitationally lensed quasars, compiled from existing strong lens and X-ray catalogues. Images of HSC J091843.27–022007.5 show a red galaxy with two blue point sources at either side, separated by 2.26 arcsec. This system has a source and a lens redshifts zs = 0.804 and zℓ = 0.459, respectively, as obtained by our follow-up spectroscopic data. CXCO J100201.50+020330.0 shows two point sources separated by 0.85 arcsec on either side of an early-type galaxy. The follow-up spectroscopic data confirm the fainter quasar has the same redshift with the brighter quasar from the Sloan Digital Sky Survey (SDSS) fiber spectrum at zs = 2.016. The deflecting foreground galaxy is a typical early-type galaxy at a redshift of zℓ = 0.439. SDSS J135944.21+012809.8 has two point sources with quasar spectra at the same redshift zs = 1.096, separated by 1.05 arcsec, and fits to the HSC images confirm the presence of a galaxy between these. These discoveries demonstrate the power of the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP)’s deep imaging and wide sky coverage. Combined with existing X-ray source catalogues and follow-up spectroscopy, the HSC-SSP provides us unique opportunities to find multiple-image quasars lensed by a foreground galaxy.


2020 ◽  
Vol 494 (4) ◽  
pp. 5293-5297
Author(s):  
Duncan A Forbes ◽  
Bililign T Dullo ◽  
Jonah Gannon ◽  
Warrick J Couch ◽  
Enrichetta Iodice ◽  
...  

ABSTRACT Using deep g, r, i imaging from the VST Early-type GAlaxy Survey (VEGAS), we have searched for ultradiffuse galaxies (UDGs) in the IC 1459 group. Assuming they are group members, we identify nine galaxies with physical sizes and surface brightnesses that match the UDG criteria within our measurement uncertainties. They have mean colours of g − i = 0.6 and stellar masses of ∼108 M⊙. Several galaxies appear to have associated systems of compact objects, e.g. globular clusters. Two UDGs contain a central bright nucleus, with a third UDG revealing a remarkable double nucleus. This appears to be the first reported detection of a double nucleus in a UDG – its origin is currently unclear.


2011 ◽  
Vol 7 (S284) ◽  
pp. 262-264
Author(s):  
Nicola K. Agius ◽  
Anne E. Sansom ◽  
Cristina C. Popescu

AbstractHierarchical galaxy formation models predict the development of elliptical galaxies through a combination of the mergers and interactions of smaller galaxies. We are carrying out a study of Early-Type Galaxies (ETGs) using GAMA multi-wavelength and Herschel-ATLAS sub-mm data to understand their intrinsic dust properties. The dust in some ETGs may be a relic of past interactions and mergers of galaxies, or may be produced within the galaxies themselves. With this large dataset we will probe the properties of the dust and its relation to host galaxy properties. This paper presents our criteria for selecting ETGs and explores the usefulness of proxies for their morphology, including optical colour, Sérsic index and Concentration index. We find that a combination of criteria including r band Concentration index, ellipticity and apparent sizes is needed to select a robust sample. Optical and sub-mm parameter diagnostics are examined for the selected ETG sample, and the sub-mm data are fitted with modified Planck functions giving initial estimates for the cold dust temperatures and masses.


Author(s):  
Song-lin Li ◽  
Yong Shi ◽  
Yan-Mei Chen ◽  
Matha Tabor ◽  
Dmitry Bizyaev ◽  
...  

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