Villar-Martin, M., Tadhunter, C., Humphrey, A. et al. (4 more authors) (2011) Interactions, star formation and extended nebulae in SDSS type 2 quasars at 0.3 <= z <= 0.6. Monthly Notices of the Royal Astronomical Society, 416 (1). pp. 262-278. ISSN 0035-8711
Abstract
We present long-slit spectroscopy and imaging data obtained with the Focal Reducer and Low Dispersion Spectrograph (FORS2) on the Very Large Telescope of 13 optically selected type 2 quasars at z ∼ 0.3–0.6 from the original sample of Zakamska et al. (2003). The sample is likely to be affected by different selection biases. We investigate the evidence for (i) mergers/interactions (ii) star formation activity in the neighbourhood of the quasars and (iii) extended emission-line regions (EELRs) and their nature. Evidence for mergers/interactions is found in 5/13 objects. This is a lower limit for our sample, given the shallowness of most of our continuum images. Although active galactic nucleus (AGN) photoionization cannot be totally discarded, line ratios consistent with stellar photoionization are found in general in companion galaxies/knots/nuclei near these same objects. On the contrary, the gas in the neighbourhood of the quasar nucleus shows line ratios inconsistent with H II galaxies and typical of AGN photoionized nebulae. A natural scenario to explain the observations is that star formation is ongoing in companion galaxies/knots/nuclei, possibly triggered by the interactions. These systems are, therefore, composite in their emission-line properties showing a combination of AGN and star formation features. EELRs have been found in 7/13 objects, although this fraction might be higher if a complete spatial coverage around the quasars was performed. The sizes vary between a few and up to 64 kpc. In general, the EELR apparently consists of an extended nebula associated with the quasar. In at least one case, the EELR is associated with ionized tidal features.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2011 The Authors © 2011 RASPublished by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
Keywords: | galaxies: active; quasars: emission lines; quasars: general |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Physics and Astronomy (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 06 Nov 2017 10:01 |
Last Modified: | 06 Nov 2017 10:01 |
Published Version: | https://doi.org/10.1111/j.1365-2966.2011.19031.x |
Status: | Published |
Publisher: | Oxford University Press |
Refereed: | Yes |
Identification Number: | 10.1111/j.1365-2966.2011.19031.x |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:123512 |