To be published in ApJS.
1 Department of Astronomy, University of Cape Town, Rondebosch, South Africa
2 Centre for Astrophysics and Supercomputing, Swinburne University of Technology, John Street, Hawthorn 3122, Victoria, Australia
3 Department of Physics and Astronomy, University of the Western Cape, Robert Sobukwe Road, Bellville 7535,South Africa
4 School of Physics and Astronomy, Monash University, Clayton 3800, Victoria, Australia
5 Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071, USA
6 Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, CA, 90095, USA
7 Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125, USA
Abstract: We present mid-infrared photometry and measured global properties of the 100 largest galaxies in the sky, including the well-studied Magellanic Clouds, Local Group galaxies M 31 and M 33, the Fornax and Virgo Galaxy Cluster giants, and many of the most spectacular Messier objects (e.g., M 51 and M 83). This is the first release of a larger catalog of extended sources as imaged in the mid-infrared, called the WISE Extended Source Catalogue (WXSC). In this study we measure their global attributes, including integrated flux, surface brightness and radial distribution. The largest of the large are the LMC, SMC and the Andromeda Galaxy, which are also the brightest mid-infrared galaxies in the sky. We interrogate the large galaxies using WISE colors, which serve as proxies for four general types of galaxies: bulge-dominated spheroidals, intermediate semi-quiescent disks, star-forming spirals, and AGN-dominated. The colors reveal a tight “sequence” that spans 5 magnitudes in W2−W3 color, ranging from early to late-types, and low to high star-forming activity; we fit the functional form given by: (W1 − W2) = [0.015 × e (W2 − W3) / 1.38 ] − 0.08. Departures from this sequence may reveal nuclear, starburst, and merging events. Physical properties and luminosity attributes are computed, notably the diameter, aggregate stellar mass and the dust-obscured star formation activity. To effectively study and compare these galaxy characteristics, we introduce the ‘pinwheel’ diagram which depicts physical properties with respect to the median value observed for WISE galaxies in the local universe. Utilized with the WXSC, this diagram will delineate between different kinds of galaxies, identifying those with similar star formation and structural properties. Finally, we present the mid-infrared photometry of the 25 brightest globular clusters in the sky, for which many are also the largest and brightest objects orbiting the Milky Way, including Omega Centauri, 47 Tucanae and a number of famed night-sky targets (e.g., M 13).
Keywords : galaxies: photometry, star formation — infrared: galaxies — surveys
The paper is in pdf format.