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The search for active black holes in nearby low-mass galaxies using optical and mid-IR data.
- Source :
- Monthly Notices of the Royal Astronomical Society; 12/21/2015, Vol. 454 Issue 4, p3722-3742, 21p
- Publication Year :
- 2015
-
Abstract
- We investigated AGN activity in low-mass galaxies, an important regime that can shed light on to black hole (BH) formation and evolution, and their interaction with their host galaxies. We identified 336 AGN candidates from a parent sample of ~48 000 nearby low-mass galaxies (M* ≤ 10<superscript>9.5</superscript>M<subscript>⊙</subscript>, z < 0.1) in the Sloan Digital Sky Survey. We selected the AGN using the classical BPT diagram, a similar optical emission line diagnostic based on the He II λ4686 line, and mid-IR colour cuts. Different criteria select host galaxies with different physical properties such as stellar mass and optical colour and only 3 out of 336 sources fulfil all three criteria. This could be in part due to selection biases. The resulting AGN fraction of ~0.7 per cent is at least one order of magnitude below the one estimated for more massive galaxies. At optical wavelengths, the He II -based AGN selection appears to be more sensitive to AGN hosted in star-forming galaxies than the classical BPT diagram, at least in the low-mass regime. The archival X-ray and radio data available for some of the AGN candidates seem to confirm their AGN nature, but follow-up observations are needed to confirm the AGN nature of the rest of the sample, especially in the case of mid-IR selection. Our sample will be important for future follow-up studies aiming to understand the relation between BHs and host galaxies in the low-mass regime. [ABSTRACT FROM AUTHOR]
- Subjects :
- BLACK holes
LOW mass stars
GALAXIES
ACTIVE galactic nuclei
ASTRONOMICAL observations
Subjects
Details
- Language :
- English
- ISSN :
- 00358711
- Volume :
- 454
- Issue :
- 4
- Database :
- Complementary Index
- Journal :
- Monthly Notices of the Royal Astronomical Society
- Publication Type :
- Academic Journal
- Accession number :
- 111112169
- Full Text :
- https://doi.org/10.1093/mnras/stv2238