English

Detecting Radio-AGN signatures in Red geysers

Astrophysics of Galaxies 2018-12-26 v1

Abstract

A new class of quiescent galaxies harboring possible AGN-driven winds has been discovered using spatially resolved optical spectroscopy from the ongoing SDSS-IV MaNGA survey. These galaxies, termed "red geysers", constitute 510%5-10\% of the local quiescent population and are characterized by narrow bisymmetric patterns in ionized gas emission features. Cheung et al. argued that these galaxies host large-scale AGN-driven winds that may play a role in suppressing star formation at late times. In this work, we test the hypothesis that AGN activity is ultimately responsible for the red geyser phenomenon. We compare the nuclear radio activity of the red geysers to a matched control sample with similar stellar mass, redshift, rest frame NUVrNUV-r color, axis ratio and presence of ionized gas. We have used the 1.4 GHz radio continuum data from VLA FIRST survey to stack the radio flux from the red geyser and control samples. In addition to a 3 times higher FIRST detection rate, we find that red geysers have a 5σ\sigma higher level of average radio flux than control galaxies. After restricting to rest-frame NUVrNUV-r color >> 5 and checking mid-IR WISE photometry, we rule out star formation contamination and conclude that red geysers are associated with more active AGN. Red geysers and a possibly-related class with disturbed Hα\alpha emission account for 40\% of all radio-detected red galaxies with log (M/M)<11\rm log~(M_\star/M_\odot) < 11. Our results support a picture in which episodic AGN activity drives large-scale-relatively weak ionized winds that may provide a feedback mechanism for many early-type galaxies.

Keywords

Cite

@article{arxiv.1811.04072,
  title  = {Detecting Radio-AGN signatures in Red geysers},
  author = {Namrata Roy and Kevin Bundy and Edmond Cheung and Wiphu Rujopakarn and Michele Cappellari and Francesco Belfiore and Renbin Yan and Tim Heckman and Matthew Bershady and Jenny Greene and Kyle Westfall and Niv Drory and Kate Rubin and David Law and Kai Zhang and Joseph Gelfand and Dmitry Bizyaev and David Wake and Karen Masters and Daniel Thomas and Cheng Li and Rogemar A. Riffel},
  journal= {arXiv preprint arXiv:1811.04072},
  year   = {2018}
}

Comments

15 pages, 10 figures, accepted for publication in the Astrophysical journal