The environmental impacts on the star formation main sequence: an H-alpha study of the newly discovered rich cluster at z=1.52. Koyama, Y., Kodama, T., Tadaki, K., Hayashi, M., Tanaka, I., & Shimakawa, R. The Astrophysical Journal, 789(1):18, June, 2014. arXiv: 1405.4165
The environmental impacts on the star formation main sequence: an H-alpha study of the newly discovered rich cluster at z=1.52 [link]Paper  doi  abstract   bibtex   
We report the discovery of a strong over-density of galaxies in the field of a radio galaxy at z=1.52 (4C65.22) based on our broad-band and narrow-band (H-alpha) photometry with Subaru Telescope. We find that H-alpha emitters are located in the outskirts of the density peak (cluster core) dominated by passive red-sequence galaxies. This resembles the situation in lower-redshift clusters, suggesting that the newly discovered structure is a well-evolved rich galaxy cluster at z=1.5. Our data suggest that the color-density and stellar mass-density relations are already in place at z\textasciitilde1.5, mostly driven by the passive red massive galaxies residing within Rc\textless200 kpc from the cluster core. These environmental trends almost disappear when we consider only star-forming (SF) galaxies. We do not find SFR-density or SSFR-density relations amongst SF galaxies, and the location of the SF main sequence does not significantly change with environment. Nevertheless, we find a tentative hint that star-bursting galaxies (up-scattered objects from the main sequence) are preferentially located in a small group at \textasciitilde1-Mpc away from the main body of the cluster. We also argue that the scatter of the SF main sequence could be dependent on the distance to the nearest neighboring galaxy.
@article{koyama_environmental_2014,
	title = {The environmental impacts on the star formation main sequence: an {H}-alpha study of the newly discovered rich cluster at z=1.52},
	volume = {789},
	issn = {0004-637X, 1538-4357},
	shorttitle = {The environmental impacts on the star formation main sequence},
	url = {http://arxiv.org/abs/1405.4165},
	doi = {10.1088/0004-637X/789/1/18},
	abstract = {We report the discovery of a strong over-density of galaxies in the field of a radio galaxy at z=1.52 (4C65.22) based on our broad-band and narrow-band (H-alpha) photometry with Subaru Telescope. We find that H-alpha emitters are located in the outskirts of the density peak (cluster core) dominated by passive red-sequence galaxies. This resembles the situation in lower-redshift clusters, suggesting that the newly discovered structure is a well-evolved rich galaxy cluster at z=1.5. Our data suggest that the color-density and stellar mass-density relations are already in place at z{\textasciitilde}1.5, mostly driven by the passive red massive galaxies residing within Rc{\textless}200 kpc from the cluster core. These environmental trends almost disappear when we consider only star-forming (SF) galaxies. We do not find SFR-density or SSFR-density relations amongst SF galaxies, and the location of the SF main sequence does not significantly change with environment. Nevertheless, we find a tentative hint that star-bursting galaxies (up-scattered objects from the main sequence) are preferentially located in a small group at {\textasciitilde}1-Mpc away from the main body of the cluster. We also argue that the scatter of the SF main sequence could be dependent on the distance to the nearest neighboring galaxy.},
	number = {1},
	journal = {The Astrophysical Journal},
	author = {Koyama, Yusei and Kodama, Tadayuki and Tadaki, Ken-ichi and Hayashi, Masao and Tanaka, Ichi and Shimakawa, Rhythm},
	month = jun,
	year = {2014},
	note = {arXiv: 1405.4165},
	keywords = {Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics},
	pages = {18},
}

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