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Title: GREEN GALAXIES IN THE COSMOS FIELD

Abstract

We present research on the morphologies, spectra, and environments of ≈2350 'green valley' galaxies at 0.2 < z < 1.0 in the COSMOS field. The bimodality of dust-corrected NUV–r {sup +} color is used to define 'green valley'; it removes dusty star-forming galaxies from galaxies that are truly transitioning between the blue cloud and the red sequence. Morphological parameters of green galaxies are intermediate between those of blue and red galaxy populations, both on the Gini-asymmetry and the Gini-M{sub 20} planes. Approximately 60%-70% of green disk galaxies have intermediate or big bulges, and only 5%-10% are pure disk systems, based on morphological classification using the Zurich Estimator of Structural Types. The obtained average spectra of green galaxies are intermediate between blue and red ones in terms of [O II], Hα, and Hβ emission lines. Stellar population synthesis on the average spectra shows that green galaxies are on average older than blue galaxies but younger than red galaxies. Green galaxies and blue galaxies have similar projected galaxy density (Σ{sub 10}) distributions at z > 0.7. At z < 0.7, the fractions of M{sub *} < 10{sup 10.0} M{sub ☉} green galaxies located in a dense environment are found to be significantlymore » larger than those of blue galaxies. The morphological and spectral properties of green galaxies are consistent with the transitioning population between the blue cloud and the red sequence. The possible mechanisms for quenching star formation activities in green galaxies are discussed. The importance of active galactic nucleus feedback cannot be well constrained in our study. Finally, our findings suggest that environmental conditions, most likely starvation and harassment, significantly affect the transformation of M{sub *} < 10{sup 10.0} M{sub ☉} blue galaxies into red galaxies, especially at z < 0.5.« less

Authors:
; ;  [1]
  1. Center of Astrophysics, University of Science and Technology of China, Hefei 230026 (China)
Publication Date:
OSTI Identifier:
22270892
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 776; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; APPROXIMATIONS; ASTRONOMY; ASTROPHYSICS; ASYMMETRY; CLASSIFICATION; COSMIC DUST; DENSITY; DISTRIBUTION; DUSTS; EMISSION; EVOLUTION; FASTING; FEEDBACK; GALAXIES; GALAXY NUCLEI; INTERACTIONS; MORPHOLOGY; NUCLEI; OXYGEN IONS; QUENCHING; STAR EVOLUTION; STARS; SYNTHESIS; TRANSFORMATIONS; UNIVERSE

Citation Formats

Pan, Zhizheng, Kong, Xu, and Fan, Lulu. GREEN GALAXIES IN THE COSMOS FIELD. United States: N. p., 2013. Web. doi:10.1088/0004-637X/776/1/14.
Pan, Zhizheng, Kong, Xu, & Fan, Lulu. GREEN GALAXIES IN THE COSMOS FIELD. United States. https://doi.org/10.1088/0004-637X/776/1/14
Pan, Zhizheng, Kong, Xu, and Fan, Lulu. 2013. "GREEN GALAXIES IN THE COSMOS FIELD". United States. https://doi.org/10.1088/0004-637X/776/1/14.
@article{osti_22270892,
title = {GREEN GALAXIES IN THE COSMOS FIELD},
author = {Pan, Zhizheng and Kong, Xu and Fan, Lulu},
abstractNote = {We present research on the morphologies, spectra, and environments of ≈2350 'green valley' galaxies at 0.2 < z < 1.0 in the COSMOS field. The bimodality of dust-corrected NUV–r {sup +} color is used to define 'green valley'; it removes dusty star-forming galaxies from galaxies that are truly transitioning between the blue cloud and the red sequence. Morphological parameters of green galaxies are intermediate between those of blue and red galaxy populations, both on the Gini-asymmetry and the Gini-M{sub 20} planes. Approximately 60%-70% of green disk galaxies have intermediate or big bulges, and only 5%-10% are pure disk systems, based on morphological classification using the Zurich Estimator of Structural Types. The obtained average spectra of green galaxies are intermediate between blue and red ones in terms of [O II], Hα, and Hβ emission lines. Stellar population synthesis on the average spectra shows that green galaxies are on average older than blue galaxies but younger than red galaxies. Green galaxies and blue galaxies have similar projected galaxy density (Σ{sub 10}) distributions at z > 0.7. At z < 0.7, the fractions of M{sub *} < 10{sup 10.0} M{sub ☉} green galaxies located in a dense environment are found to be significantly larger than those of blue galaxies. The morphological and spectral properties of green galaxies are consistent with the transitioning population between the blue cloud and the red sequence. The possible mechanisms for quenching star formation activities in green galaxies are discussed. The importance of active galactic nucleus feedback cannot be well constrained in our study. Finally, our findings suggest that environmental conditions, most likely starvation and harassment, significantly affect the transformation of M{sub *} < 10{sup 10.0} M{sub ☉} blue galaxies into red galaxies, especially at z < 0.5.},
doi = {10.1088/0004-637X/776/1/14},
url = {https://www.osti.gov/biblio/22270892}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 776,
place = {United States},
year = {Thu Oct 10 00:00:00 EDT 2013},
month = {Thu Oct 10 00:00:00 EDT 2013}
}