TY - JOUR
T1 - P-MaNGA
T2 - GRADIENTS in RECENT STAR FORMATION HISTORIES AS DIAGNOSTICS for GALAXY GROWTH and DEATH
AU - Li, Cheng
AU - Wang, Enci
AU - Lin, Lin
AU - Bershady, Matthew A.
AU - Bundy, Kevin
AU - Tremonti, Christy A.
AU - Xiao, Ting
AU - Yan, Renbin
AU - Bizyaev, Dmitry
AU - Blanton, Michael
AU - Cales, Sabrina
AU - Cherinka, Brian
AU - Cheung, Edmond
AU - Drory, Niv
AU - Emsellem, Eric
AU - Fu, Hai
AU - Gelfand, Joseph
AU - Law, David R.
AU - Lin, Lihwai
AU - MacDonald, Nick
AU - Maraston, Claudia
AU - Masters, Karen L.
AU - Merrifield, Michael R.
AU - Pan, Kaike
AU - Sánchez, S. F.
AU - Schneider, Donald P.
AU - Thomas, Daniel
AU - Wake, David
AU - Wang, Lixin
AU - Weijmans, Anne Marie
AU - Wilkinson, David
AU - Yoachim, Peter
AU - Zhang, Kai
AU - Zheng, Tiantian
N1 - Publisher Copyright:
© 2015. The American Astronomical Society. All rights reserved.
PY - 2015/5/10
Y1 - 2015/5/10
N2 - We present an analysis of the data produced by the MaNGA prototype run (P-MaNGA), aiming to test how the radial gradients in recent star formation histories, as indicated by the 4000 Šbreak (Dn(4000)), Hδ absorption (EW(HδA)), and H emission (EW(H)) indices, can be useful for understanding disk growth and star formation cessation in local galaxies. We classify 12 galaxies observed on two P-MaNGA plates as either centrally quiescent (CQ) or centrally star-forming (CSF), according to whether Dn(4000) measured in the central spaxel of each datacube exceeds 1.6. For each spaxel we generate both 2D maps and radial profiles of Dn(4000), EW(HδA), and EW(H). We find that CSF galaxies generally show very weak or no radial variation in these diagnostics. In contrast, CQ galaxies present significant radial gradients, in the sense that Dn(4000) decreases, while both EW(HδA) and EW(H) increase from the galactic center outward. The outer regions of the galaxies show greater scatter on diagrams relating the three parameters than their central parts. In particular, the clear separation between centrally measured quiescent and star-forming galaxies in these diagnostic planes is largely filled in by the outer parts of galaxies whose global colors place them in the green valley, supporting the idea that the green valley represents a transition between blue-cloud and red-sequence phases, at least in our small sample. These results are consistent with a picture in which the cessation of star formation propagates from the center of a galaxy outward as it moves to the red sequence.
AB - We present an analysis of the data produced by the MaNGA prototype run (P-MaNGA), aiming to test how the radial gradients in recent star formation histories, as indicated by the 4000 Šbreak (Dn(4000)), Hδ absorption (EW(HδA)), and H emission (EW(H)) indices, can be useful for understanding disk growth and star formation cessation in local galaxies. We classify 12 galaxies observed on two P-MaNGA plates as either centrally quiescent (CQ) or centrally star-forming (CSF), according to whether Dn(4000) measured in the central spaxel of each datacube exceeds 1.6. For each spaxel we generate both 2D maps and radial profiles of Dn(4000), EW(HδA), and EW(H). We find that CSF galaxies generally show very weak or no radial variation in these diagnostics. In contrast, CQ galaxies present significant radial gradients, in the sense that Dn(4000) decreases, while both EW(HδA) and EW(H) increase from the galactic center outward. The outer regions of the galaxies show greater scatter on diagrams relating the three parameters than their central parts. In particular, the clear separation between centrally measured quiescent and star-forming galaxies in these diagnostic planes is largely filled in by the outer parts of galaxies whose global colors place them in the green valley, supporting the idea that the green valley represents a transition between blue-cloud and red-sequence phases, at least in our small sample. These results are consistent with a picture in which the cessation of star formation propagates from the center of a galaxy outward as it moves to the red sequence.
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U2 - 10.1088/0004-637X/804/2/125
DO - 10.1088/0004-637X/804/2/125
M3 - Article
AN - SCOPUS:84929992642
SN - 0004-637X
VL - 804
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 125
ER -