Astronomy and Astrophysics – Astronomy
Scientific paper
Jan 2011
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011aas...21714207c&link_type=abstract
American Astronomical Society, AAS Meeting #217, #142.07; Bulletin of the American Astronomical Society, Vol. 43, 2011
Astronomy and Astrophysics
Astronomy
1
Scientific paper
Motivated by the discovery of Hanny's Voorwerp, a 45-kpc highly-ionized cloud near the spiral galaxy IC 2497, and accompanying evidence for strong variability of its AGN over 105 year scales, members of the Galaxy Zoo project have carried out surveys for similar (albeit smaller) ionized clouds around galaxies both with and without spectroscopic AGN. The color-composite SDSS images detect strong [OIII] in the g band at low z, allowing a useful color search of Galaxy Zoo targets. In addition, a targeted search was made of over 16,000 spectroscopic AGN and candidates. We used SDSS data to produce crude [OIII] images of the top candidates, and obtained long-slit optical spectra from KPNO and Lick for 30 of the most promising. Roughly half of the spectra showed extended [OIII]λ5007 emission, some exceeding 30 kpc in radial extent. Of the 16 extended clouds we identified, 11 lie in strongly interacting or merging systems, probably because these events leave cold gas out of the plane to be ionized. Most nuclei of extended cloud hosts are type 2 Seyferts. We consider the energy budgets, between ionizing luminosity required for the most distant line emission and the FIR output of the nucleus, to see whether any suggest strong variability rather than obscuration. Several galaxies have such strong mismatches that obscuration alone becomes implausible as an explanation for the strong ionizing continuum, and are candidates for fading events similar to that in IC 2497 and Hanny's Voorwerp. This project was funded by the National Science Foundation Research Experiences for Undergraduates (REU) program through grant NSF AST-1004872.
Chojnowski Drew
Keel William C.
No associations
LandOfFree
Galaxy-scale Clouds Of Ionized Gas Around Agn - History And Obscuration does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Galaxy-scale Clouds Of Ionized Gas Around Agn - History And Obscuration, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Galaxy-scale Clouds Of Ionized Gas Around Agn - History And Obscuration will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1394210