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Catching Quenching Galaxies: The Nature of the WISE Infrared Transition Zone

Alatalo, Katherine and Cales, Sabrina L. and Appleton, Philip N. and Kewley, Lisa J. and Lacy, Mark and Lisenfeld, Ute and Nyland, Kristina and Rich, Jeffrey A. (2014) Catching Quenching Galaxies: The Nature of the WISE Infrared Transition Zone. Astrophysical Journal Letters, 794 (1). Art. No. L13. ISSN 2041-8205. doi:10.1088/2041-8205/794/1/L13.

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We present the discovery of a prominent bifurcation between early-type galaxies and late-type galaxies, in [4.6]–[12] μm colors from the Wide Field Infrared Survey Explorer (WISE). We then use an emission-line diagnostic comparison sample to explore the nature of objects found both within and near the edges of this WISE infrared transition zone (IRTZ). We hypothesize that this bifurcation might be due to the presence of hot dust and polyaromatic hydrocarbon (PAH) emission features in late-type galaxies. Using a sample of galaxies selected through the Shocked Poststarburst Galaxy Survey (SPOGS), we are able to identify galaxies with strong Balmer absorption (EW(Hδ) > 5 Å) as well as emission lines inconsistent with star formation (deemed SPOG candidates, or SPOGs*) that lie within the optical green valley. Seyferts and low-ionization nuclear emission line regions, whose u − r colors tend to be red, are strongly represented within IRTZ, whereas SPOGs* tend to sit near the star-forming edge. Although active galactic nuclei are well represented in the IRTZ, we argue that the dominant IRTZ population is composed of galaxies that are in late stages of transitioning across the optical green valley, shedding the last of their remnant interstellar media.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Alatalo, Katherine0000-0002-4261-2326
Cales, Sabrina L.0000-0002-0489-1686
Appleton, Philip N.0000-0002-7607-8766
Kewley, Lisa J.0000-0001-8152-3943
Lacy, Mark0000-0002-3032-1783
Lisenfeld, Ute0000-0002-9471-5423
Nyland, Kristina0000-0003-1991-370X
Rich, Jeffrey A.0000-0002-5807-5078
Additional Information:© 2014 The American Astronomical Society. Received 2014 August 7; accepted 2014 September 6; published 2014 September 30. K.A. thanks Kevin Schawinski for giving full access to his early- and late-type galaxy sample, as well as Theodoros Bitsakis and Patrick Ogle for insightful discussions, Michelle Cluver and Roc Cutri for WISE advice, and finally the referee for an informative and insightful report that improved the Letter. K.A. is supported by funding through Herschel, a European Space Agency Cornerstone Mission with significant participation by NASA, through an award issued by JPL/Caltech. K.N. is supported by NSF grant 1109803. S.L.C. was supported by ALMA-CONICYT program 31110020. U.L. acknowledges support by the research projects AYA2011-24728 from the Spanish Ministerio de Ciencia y Educación and the Junta de Andalucía (Spain) grants FQM108. This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. This research has made use of the Sloan Digital Sky Survey.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Herschel Space ObservatoryUNSPECIFIED
Comisión Nacional de Investigación Científica y Tecnológica (CONICYT)31110020
Ministerio de Ciencia y Educaciόn (MEC)AYA2011-24728
Junta de AndalucíaFQM108
Subject Keywords:galaxies: evolution, galaxies: ISM, galaxies: star formation, infrared: galaxies
Issue or Number:1
Record Number:CaltechAUTHORS:20140929-144042346
Persistent URL:
Official Citation:Catching Quenching Galaxies: The Nature of the WISE Infrared Transition Zone Katherine Alatalo et al. 2014 ApJ 794 L13
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:50105
Deposited By: Ruth Sustaita
Deposited On:02 Oct 2014 20:43
Last Modified:10 Nov 2021 18:52

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