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dc.contributor.authorSeymour, Nick
dc.contributor.authorOgle, P.
dc.contributor.authorDe Breuck, C.
dc.contributor.authorFazio, G.
dc.contributor.authorGalametz, A.
dc.contributor.authorHaas, M.
dc.contributor.authorLacy, M.
dc.contributor.authorSajina, A.
dc.contributor.authorStern, D.
dc.contributor.authorWillner, S.
dc.contributor.authorVernet, J.
dc.date.accessioned2017-01-30T12:24:48Z
dc.date.available2017-01-30T12:24:48Z
dc.date.created2016-09-12T08:37:03Z
dc.date.issued2008
dc.identifier.citationSeymour, N. and Ogle, P. and De Breuck, C. and Fazio, G. and Galametz, A. and Haas, M. and Lacy, M. et al. 2008. Mid-infrared spectra of high-redshift (z > 2) radio galaxies. Astrophysical Journal. 681 (1 PART 2): pp. L1-L4.
dc.identifier.urihttp://hdl.handle.net/20.500.11937/21360
dc.identifier.doi10.1086/590081
dc.description.abstract

We present the first mid-infrared Spitzer/Infraxed Spectrograph (IRS) observations of powerful radio galaxies at z > 2. These radio galaxies, 4C +23.56 (z = 2.48) and 6C J1908+7220 (z = 3.53), both show strong midinfrared continua, but with 6C J1908+7220 also showing strong PAH emission at rest-frame 6.2 and 7.7 µm. In 4C +23.56 we see no obvious PAH features above the continuum. The PAH emission in 6C J1908+7220 is the among the most distant observed to date and implies that there is a large instantaneous star formation rate (SFR). This is consistent with the strong detection of 6C J1908+7220 at far-IR and sub-mm wavelengths, indicative of large amounts of cold dust, ~109 M? Powerful radio galaxies at lower redshifts tend to have weak or undetectable PAH features and typically have lower far-IR luminosities. In addition, 4C +23.56 shows moderate silicate absorption as seen in less luminous radio galaxies, indicating T 9.7 µm = 0.3 ± 0.05. This feature is shifted out of the observed wavelength range for 6C J1908+7220. The correlation of strong PAH features with large amounts of cold dust, despite the presence of a powerful AGN, is in agreement with other recent results and implies that star formation at high redshift is. in some cases at least, associated with powerful, obscured AGN. © 2008, The American Astronomical Society. All rights reserved.

dc.publisherInstitute of Physics Publishing
dc.titleMid-infrared spectra of high-redshift (z > 2) radio galaxies
dc.typeJournal Article
dcterms.source.volume681
dcterms.source.number1 PART 2
dcterms.source.startPageL1
dcterms.source.endPageL4
dcterms.source.issn0004-637X
dcterms.source.titleAstrophysical Journal
curtin.departmentDepartment of Physics and Astronomy
curtin.accessStatusOpen access via publisher


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