The Unam-Kias Catalog of Isolated Galaxies

Hernández-Toledo, H. M.; Vázquez-Mata, J. A.; Martínez-Vázquez, L. A.; Choi, Yun‐Young; Park, Changbom

doi:10.1088/0004-6256/139/6/2525

Cited by 56 publications

(57 citation statements)

References 45 publications

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“…The simulations of Mastropietro et al (2005) have shown that indeed late-type spirals can be reprocessed into early-type dwarfs through cluster processes (such as harassment) and that these dwarfs do retain their stellar disk structure. On the other hand, observations of a small number of isolated early-type dwarf galaxies (e.g., Fuse 2008;Hernández-Toledo et al 2010) argue against cluster transformation processes as the sole explanation for the formation of these objects.…”

Section: Discussion: Barred Dwarf Galaxies In the Coma Corementioning

confidence: 99%

THEHST/ACS COMA CLUSTER SURVEY. VIII. BARRED DISK GALAXIES IN THE CORE OF THE COMA CLUSTER

Marinova

Jogee

Weinzirl

et al. 2012

ApJ

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We use high-resolution (∼0. 1) F814W Advanced Camera for Surveys (ACS) images from the Hubble Space Telescope ACS Treasury survey of the Coma cluster at z ∼ 0.02 to study bars in massive disk galaxies (S0s), as well as low-mass dwarf galaxies in the core of the Coma cluster, the densest environment in the nearby universe. Our study helps to constrain the evolution of bars and disks in dense environments and provides a comparison point for studies in lower density environments and at higher redshifts. Our results are: (1) we characterize the fraction and properties of bars in a sample of 32 bright (M V −18, M * > 10 9.5 M ) S0 galaxies, which dominate the population of massive disk galaxies in the Coma core. We find that the measurement of a bar fraction among S0 galaxies must be handled with special care due to the difficulty in separating unbarred S0s from ellipticals, and the potential dilution of the bar signature by light from a relatively large, bright bulge. The results depend sensitively on the method used: the bar fraction for bright S0s in the Coma core is 50% ± 11%, 65% ± 11%, and 60% ± 11% based on three methods of bar detection, namely, strict ellipse fit criteria, relaxed ellipse fit criteria, and visual classification. (2) We compare the S0 bar fraction across different environments (the Coma core, A901/902, and Virgo) adopting the critical step of using matched samples and matched methods in order to ensure robust comparisons. We find that the bar fraction among bright S0 galaxies does not show a statistically significant variation (within the error bars of ±11%) across environments which span two orders of magnitude in galaxy number density (n ∼ 300-10,000 galaxies Mpc −3 ) and include rich and poor clusters, such as the core of Coma, the A901/902 cluster, and Virgo. We speculate that the bar fraction among S0s is not significantly enhanced in rich clusters compared to low-density environments for two reasons. First, S0s in rich clusters are less prone to bar instabilities as they are dynamically heated by harassment and are gas poor as a result of ram pressure stripping and accelerated star formation. Second, high-speed encounters in rich clusters may be less effective than slow, strong encounters in inducing bars. (3) We also take advantage of the high resolution of the ACS (∼50 pc) to analyze a sample of 333 faint (M V > −18) dwarf galaxies in the Coma core. Using visual inspection of unsharp-masked images, we find only 13 galaxies with bar and/or spiral structure. An additional eight galaxies show evidence for an inclined disk. The paucity of disk structures in Coma dwarfs suggests that either disks are not common in these galaxies or that any disks present are too hot to develop instabilities.

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Section: Discussion: Barred Dwarf Galaxies In the Coma Corementioning

confidence: 99%

THEHST/ACS COMA CLUSTER SURVEY. VIII. BARRED DISK GALAXIES IN THE CORE OF THE COMA CLUSTER

Marinova

Jogee

Weinzirl

et al. 2012

ApJ

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“…This average overlap is mainly due to the different isolation criteria. The isolation criterion followed by Hernández-Toledo et al (2010) is a mixed criterion between the CIG and a pure 3D definition. The distribution of the distance for neighbours with ∆ ≤ 500 km s −1 within 1 Mpc around galaxies in the comparison samples is shown in Fig.…”

Section: Comparison With Previous Existing Cataloguesmentioning

confidence: 99%

Catalogues of isolated galaxies, isolated pairs, and isolated triplets in the local Universe

Argudo-Fernández

Verley

Bergond

et al. 2015

A&A

106

126

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Context. The construction of catalogues of galaxies and the a posteriori study of galaxy properties in relation to their environment have been hampered by scarce redshift information. The new 3-dimensional (3D) surveys permit small, faint, physically bound satellites to be distinguished from a background-projected galaxy population, giving a more comprehensive 3D picture of the surroundings. Aims. We aim to provide representative samples of isolated galaxies, isolated pairs, and isolated triplets for testing galaxy evolution and secular processes in low density regions of the local Universe, as well as to characterise their local and large-scale environments. Methods. We used spectroscopic data from the tenth data release of the Sloan Digital Sky Survey (SDSS-DR10) to automatically and homogeneously compile catalogues of 3702 isolated galaxies, 1240 isolated pairs, and 315 isolated triplets in the local Universe (z ≤ 0.080). To quantify the effects of their local and large-scale environments, we computed the projected density and the tidal strength for the brightest galaxy in each sample. Results. We find evidence of isolated pairs and isolated triplets that are physically bound at projected separations up to d ≤ 450 kpc with radial velocity difference ∆ ≤ 160 km s −1 , where the effect of the companion typically accounts for more than 98% of the total tidal strength affecting the central galaxy. For galaxies in the catalogues, we provide their positions, redshifts, and degrees of relation with their physical and large-scale environments. The catalogues are publicly available to the scientific community. Conclusions. For isolated galaxies, isolated pairs, and isolated triplets, there is no difference in their degree of interaction with the large-scale structure (up to 5 Mpc), which may suggest that they have a common origin in their formation and evolution. We find that most of them belong to the outer parts of filaments, walls, and clusters, and generally differ from the void population of galaxies.

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“…Our sample comes from the catalog of local isolated galaxies by Hernández-Toledo et al (2010), which includes the redshift information creating a robust isolated sample of pure Es. We explore whether very isolated ellipticals differ in some photometric, spectroscopic, and structural properties with those of the Coma supercluster, and whether both isolated and highdensity ellipticals follow similar correlations with mass.…”

Section: Introductionmentioning

confidence: 99%

Isolated elliptical galaxies in the local Universe

Lacerna

Hernández-Toledo

Avila-Reese

et al. 2016

A&A

Self Cite

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Context. We have studied a sample of 89 very isolated, elliptical galaxies at z < 0.08 and compared their properties with elliptical galaxies located in a high-density environment such as the Coma supercluster. Aims. Our aim is to probe the role of environment on the morphological transformation and quenching of elliptical galaxies as a function of mass. In addition, we elucidate the nature of a particular set of blue and star-forming isolated ellipticals identified here. Methods. We studied physical properties of ellipticals, such as color, specific star formation rate, galaxy size, and stellar age, as a function of stellar mass and environment based on SDSS data. We analyzed the blue and star-forming isolated ellipticals in more detail, through photometric characterization using GALFIT, and infer their star formation history using STARLIGHT. Results. Among the isolated ellipticals ≈20% are blue, < ∼ 8% are star forming, and ≈10% are recently quenched, while among the Coma ellipticals ≈8% are blue and just < ∼ 1% are star forming or recently quenched. There are four isolated galaxies (≈4.5%) that are blue and star forming at the same time. These galaxies, with masses between 7 × 10 9 and 2 × 10 10 h −2 M , are also the youngest galaxies with light-weighted stellar ages < ∼ 1 Gyr and exhibit bluer colors toward the galaxy center. Around 30-60% of their presentday luminosity, but only <5% of their present-day mass, is due to star formation in the last 1 Gyr. Conclusions. The processes of morphological transformation and quenching seem to be in general independent of environment since most of elliptical galaxies are "red and dead", although the transition to the red sequence should be faster for isolated ellipticals. In some cases, the isolated environment seems to propitiate the rejuvenation of ellipticals by recent (<1 Gyr) cold gas accretion.

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The Unam-Kias Catalog of Isolated Galaxies

Cited by 56 publications

References 45 publications

THEHST/ACS COMA CLUSTER SURVEY. VIII. BARRED DISK GALAXIES IN THE CORE OF THE COMA CLUSTER

THEHST/ACS COMA CLUSTER SURVEY. VIII. BARRED DISK GALAXIES IN THE CORE OF THE COMA CLUSTER

Catalogues of isolated galaxies, isolated pairs, and isolated triplets in the local Universe

Isolated elliptical galaxies in the local Universe

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