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AGN All the Way Down? AGN-like Line Ratios Are Common in the Lowest-mass Isolated Quiescent Galaxies.
- Source :
-
Astrophysical Journal . 10/20/2019, Vol. 884 Issue 2, p1-1. 1p. - Publication Year :
- 2019
-
Abstract
- We investigate the lowest-mass quiescent galaxies known to exist in isolated environments (; 1.5 Mpc from a more massive galaxy). This population may represent the lowest stellar mass galaxies in which internal feedback quenches galaxy-wide star formation. We present a Keck/Echelle Spectrograph and Imager long-slit spectroscopy for 27 isolated galaxies in this regime (20 quiescent galaxies and 7 star-forming galaxies). We measure emission line strengths as a function of radius and place galaxies on the Baldwin–Phillips–Terlevich (BPT) diagram. Remarkably, 16 of 20 quiescent galaxies in our sample host central active galactic nucleus (AGN)-like line ratios. Only five of these quiescent galaxies were identified as AGN-like in the Sloan Digital Sky Survey due to a lower spatial resolution and signal-to-noise ratio. We find that many of the quiescent galaxies in our sample have spatially extended emission across the non-star-forming regions of BPT-space. While quenched galaxies in denser environments in this mass range often show no evidence for AGN activity, a significant fraction of quiescent galaxies in isolation host AGNs despite their overall passive appearances. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 0004637X
- Volume :
- 884
- Issue :
- 2
- Database :
- Academic Search Index
- Journal :
- Astrophysical Journal
- Publication Type :
- Academic Journal
- Accession number :
- 139263996
- Full Text :
- https://doi.org/10.3847/1538-4357/ab3220