5. Results

The 100 largest galaxies in the ATLAS, presented in order of the 2.2 µm isophotal diameter, are given in Tables 1 and 2. Table 1 lists the position, orientation and size parameters, and Table 2 the photometry and surface brightness results. For comparison purposes, we include the Milky Way globular cluster, NGC 104 ("47 Tuc") in the galaxy sample, representing a highly resolved, compact example of a "local" spheroid galaxy. The largest galaxies are incorporated in the 2MASS XSC. A more extensive and complete table can be found at IRSA (http://irsa.ipac.caltech.edu/). For Table 1 the columns are as follows: (1-3) are the name (we usually adopt the most common name that the galaxy is known by), NGC #, and de Vaucouleurs classification/morphology, as given in NED; (4) equatorial coordinates in J2000; (5-6) axial ratio (semi minor-to-major ratio, b/a) and position angle as determined at the 3-sigma isophote of the Ks-band, (7) Ks-band 20 mag arcsec-2 isophotal radius (major axis) in arcsec; (8) Kron radius in arcsec; (9) surface brightness extrapolation or "total" diameter in arcsec; (10-12), J, H and Ks half-light "effective" radius. For Table 2, the columns are as follows: (1) name, (2-4) Ks-band 20 mag arcsec-2 isophotal photometry: J, H and Ks mags and uncertainties, respectively, (5-7) extrapolated surface brightness profile "total" photometry: J, H and Ks mags and uncertainties, respectively, and (8-10) half-light "effective" mean surface brightness in mag arcsec-2: J, H and Ks, respectively.

We believe the sample of the 100 largest NIR galaxies is complete for the following reasons. We have used the RC3 to initially select the galaxies, and have processed over 500 of the largest galaxies to date. The RC3 is purported to be better than 95% complete for large galaxies outside of the Zone of Avoidance (Harold Corwin, private communication). For ZoA galaxies, we have searched other catalogs for large objects (e.g., Maffei galaxies), and we have used the 2MASS catalog itself to search for objects hidden behind the veil of the Milky Way (Jarrett et al 2000). We searched the entire UGC catalog for large galaxies not in the RC3 or ZoA, and processed the largest ones. Finally, we searched the NED database for large galaxies from smaller heterogeneous surveys. The only "large" galaxies not found in our sample are faint, low surface brightness dwarf LG galaxies (e.g., Ursa Minor Dwarf) and the Magellanic clouds (which are basically clusters of point sources in the NIR). It is still possible, if unlikely, that a large NIR galaxy, possibly obscured by the Galaxy, is not included here.

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