Using spatially resolved spectroscopy from SDSS-IV MaNGA we have demonstrated that low ionization emission-line regions (LIERs) in local galaxies result from photoionization by hot evolved stars, not active galactic nuclei, hence tracing galactic region hosting old stellar population where, despite the presence of ionized gas, star formation is no longer occurring. LIERs are ubiquitous in both quiescent galaxies and in the central regions of galaxies where star formation takes place at larger radii.We refer to these two classes of galaxies as extended LIER (eLIER) and central LIER (cLIER) galaxies, respectively. cLIERs are late-type galaxies primarily spread across the green valley, in the transition region between the star formation main sequence and quiescent galaxies. These galaxies display regular disc rotation in both stars and gas, although featuring a higher central stellar velocity dispersion than star-forming galaxies of the same mass. cLIERs are consistent with being slowly quenched inside-out; the transformation is associated with massive bulges, pointing towards the importance of bulge growth via secular evolution. eLIERs aremorphologically early types and are indistinguishable from passive galaxies devoid of line emission in terms of their stellar populations, morphology and central stellar velocity dispersion. Ionized gas in eLIERs shows both disturbed and disclike kinematics. When a large-scale flow/rotation is observed in the gas, it is often misaligned relative to the stellar component. These features indicate that eLIERs are passive galaxies harbouring a residual cold gas component, acquired mostly via external accretion. Importantly, quiescent galaxies devoid of line emission reside in denser environments and have significantly higher satellite fraction than eLIERs. Environmental effects thus represent the likely cause for the existence of line-less galaxies on the red sequence.
|Number of pages||20|
|Journal||Monthly Notices of the Royal Astronomical Society|
|State||Published - Apr 21 2017|
Bibliographical noteFunding Information:
We are grateful to the referee, A. Renzini, for his comments and insight that have greatly improved the quality of the paper. FB, RM and KM acknowledge funding from the United Kingdom Science and Technology Facilities Council (STFC). RM acknowledges support from the European Research Council (ERC) Advanced Grant 695671 'QUENCH'. AR-L acknowledges partial support from the DIULS regular project PR15143. MB was supported by NSF/AST-1517006. KB was supported byWorld Premier International Research Centre Initiative (WPI Initiative), MEXT, Japan and by JSPS KAKENHI Grant Number 15K17603. AW acknowledges support from a Leverhulme Early Career Fellowship. AD acknowledges support from The Grainger Foundation. The authors are thankful to Y. Peng and D. Goddard for their help with the environmental measures for the SDSS galaxy sample and to M. Blanton for developing and maintaining the NASASloan Atlas; to the members of the SDSS-IV MaNGA collaboration, in particular the dedicated team of observers at APO. The visual classification of the Galaxy Zoo galaxies was made by more than 100 000 volunteers. Their contributions are acknowledged at http://www.galaxyzoo.org/Volunteers.aspx. This work makes use of data from SDSS-I-II and IV. This research made use of Marvin (Cherinka et al. in preparation), a core Python package and web framework for MaNGA data, developed by Brian Cherinka, José Sánchez-Gallego and Brett Andrews. Funding for SDSS-I-II and SDSS-IV has been provided by the Alfred P. Sloan Foundation and Participating Institutions. Additional funding for SDSS-II comes the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society and the Higher Education Funding Council for England. Additional funding towards SDSS-IV has been provided by the U.S. Department of Energy Office of Science. SDSS-IV acknowledges support and resources from the Centre for High-Performance Computing at the University of Utah. The SDSS web site is www.sdss.org. The participating Institution in SDSS-II include the American Museum of Natural History, Astrophysical Institute Potsdam, University of Basel, University of Cambridge, Case Western Reserve University, University of Chicago, Drexel University, Fermilab, the Institute for Advanced Study, the Japan Participation Group, Johns Hopkins University, the Joint Institute for Nuclear Astrophysics, the Kavli Institute for Particle Astrophysics and Cosmology, the Korean Scientist Group, the Chinese Academy of Sciences (LAMOST), Los Alamos National Laboratory, Max-Planck-Institut für Astronomie (MPIA Heidelberg), Max-Planck-Institut für Astrophysik (MPA Garching), New Mexico State University, Ohio State University, University of Pittsburgh, University of Portsmouth, Princeton University, the United States Naval Observatory and the University of Washington. SDSS-IV is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS Collaboration including the Brazilian Participation Group, the Carnegie Institution for Science, Carnegie Mellon University, the Chilean Participation Group, the French Participation Group, Harvard-Smithsonian Center for Astrophysics, Instituto de Astrofísica de Canarias, The Johns Hopkins University, Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/University of Tokyo, Lawrence Berkeley National Laboratory, Leibniz Institut für Astrophysik Potsdam (AIP), Max-Planck-Institut für Astronomie (MPIA Heidelberg), Max-Planck-Institut für Astrophysik (MPA Garching), Max-Planck-Institut für Extraterrestrische Physik (MPE), National Astronomical Observatory of China, New Mexico State University, New York University, University of Notre Dame, Observatário Nacional/ MCTI, The Ohio State University, Pennsylvania State University, Shanghai Astronomical Observatory, United Kingdom Participation Group, Universidad Nacional Autónoma deMéxico, University of Arizona, University of Colorado Boulder, University of Oxford, University of Portsmouth, University of Utah, University of Virginia, University of Washington, University of Wisconsin, Vanderbilt University and Yale University.
© 2016 The Authors.
- Galaxies: ISM
- Galaxies: evolution
- Galaxies: fundamental parameters
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science