Library of Congress Cataloging-in-Publication Data Third reference catalogue of bright galaxies / Gerard de Vaucouleurs ... [et al.].p. cm. Includes bibliographical references. Contents: v. 1. Introduction, references, notes, and appendicesv.2. Data for galaxies between Oh and 12h -v.3. Data for galaxies between 12h and 24h.

Library of Congress Cataloging-in-Publication Data Third reference catalogue of bright galaxies / Gerard de Vaucouleurs ... let al.l. p. cm. Includes bibliographical references. Contents: v. 1. Introduction, references, notes, and appendicesv.2. Data for galaxies between Oh and 12h -v.3. Data for galaxies between 12h and 24h.

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ABSTRACT. The Spitzer Survey of Stellar Structure in Galaxies (S 4 G) is an Exploration Science Legacy Program approved for the Spitzer post-cryogenic mission. It is a volume-, magnitude-, and size-limited (d < 40 Mpc, jbj > 30°, m Bcorr < 15:5, and D 25 > 1 0 ) survey of 2331 galaxies using the Infrared Array Camera (IRAC) at 3.6 and 4.5 μm. Each galaxy is observed for 240 s and mapped to ≥1:5 × D 25 . The final mosaicked images have a typical 1σ rms noise level of 0.0072 and 0:0093 MJy sr À1 at 3.6 and 4.5 μm, respectively. Our azimuthally averaged surface brightness profile typically traces isophotes at μ 3:6μm ðABÞð1σÞ ∼ 27 mag arcsec À2 , equivalent to a stellar mass surface density of ∼1 M ⊙ pc À2 . S 4 G thus provides an unprecedented data set for the study of the distribution of mass and stellar structures in the local universe. This large, unbiased, and extremely deep sample of all Hubble types from dwarfs to spirals to ellipticals will allow for detailed structural studies, not only as a function of stellar mass, but also as a function of the local environment. The data from this survey will serve as a vital testbed for cosmological simulations predicting the stellar mass properties of present-day galaxies. This article introduces the survey and describes the sample selection, the significance of the 3.6 and 4.5 μm bands for this study, and the data collection and survey strategies. We describe the S 4 G data analysis pipeline and present measurements for a first set of galaxies, observed in both the cryogenic and warm mission phases of Spitzer. For every galaxy we tabulate the galaxy diameter, position angle, axial ratio, inclination at μ 3:6μm ðABÞ ¼ 25:5, and 26:5 mag arcsec À2 (equivalent to ≈μ B ðABÞ ¼ 27:2 and 28:2 mag arcsec À2 , respectively). These measurements will form the initial S 4 G catalog of galaxy properties. We also measure the total magnitude and the azimuthally averaged radial profiles of ellipticity, position angle, surface brightness, and color. Finally, using the galaxy-fitting code GALFIT, we deconstruct each galaxy into its main constituent stellar components: the bulge/spheroid, disk, bar, and nuclear point source, where necessary. Together, these data products will provide a comprehensive and definitive catalog of stellar structures, mass, and properties of galaxies in the nearby universe and will enable a variety of scientific investigations, some of which are highlighted in this introductory S 4 G survey paper.

The Spitzer Survey of Stellar Structure in Galaxies (S 4 G) is the largest available database of deep, homogeneous middle-infrared (mid-IR) images of galaxies of all types. The survey, which includes 2352 nearby galaxies, reveals galaxy morphology only minimally affected by interstellar extinction. This paper presents an atlas and classifications of S 4 G galaxies in the Comprehensive de Vaucouleurs revised Hubble-Sandage (CVRHS) system. The CVRHS system follows the precepts of classical de Vaucouleurs (1959) morphology, modified to include recognition of other features such as inner, outer, and nuclear lenses, nuclear rings, bars, and disks, spheroidal galaxies, X patterns and box/peanut structures, OLR subclass outer rings and pseudorings, bar ansae and barlenses, parallel sequence late-types, thick disks, and embedded disks in 3D early-type systems. We show that our CVRHS classifications are internally consistent, and that nearly half of the S 4 G sample consists of extreme late-type systems (mostly bulgeless, pure disk galaxies) in the range Scd-Im. The most common family classification for mid-IR types S0/a to Sc is SA while that for types Scd to Sm is SB. The bars in these two type domains are very different in mid-IR structure and morphology. This paper examines the bar, ring, and type classification fractions in the sample, and also includes several montages of images highlighting the various kinds of "stellar structures" seen in mid-IR galaxy morphology.

Photometric scaling relations are studied for S0 galaxies and compared with those obtained for spirals. New two-dimensional multi-component decompositions are presented for 122 early-type disc galaxies, using deep K s -band images. Combining them with our previous decompositions, the final sample consists of 175 galaxies (Near-Infrared Survey of S0s, NIRS0S: 117 S0s + 22 S0/a and 36 Sa galaxies). As a comparison sample we use the Ohio State University Bright Spiral Galaxy Survey (OSUBSGS) of nearly 200 spirals, for which similar multi-component decompositions have previously been made by us. The improved statistics, deep images and the homogeneous decomposition method used allow us to reevaluate the parameters of the bulges and discs. For spirals we largely confirm previous results, which are compared with those obtained for S0s. Our main results are as follows. disc), μ 0 (0)] of the S0 galaxies in NIRS0S are similar to those obtained for spirals in the OSUBSGS. Overall, our results support the view that spiral galaxies with bulges brighter than −20 mag in the K band can evolve directly into S0s, due to stripping of gas followed by truncated star formation.

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Properties of bars and bulges in the Hubble sequence are discussed, based on an analysis of 216 disc galaxies of S0‐Sm types (S0s from the Near‐Infrared S0 Survey and spirals from the Ohio State University Bright Spiral Galaxy Survey). For this purpose we have collected, and completed when necessary, the various analyses we have previously made separately for early‐ and late‐type galaxies. We find strong evidence of pseudo‐bulges in all Hubble types. Pseudo‐bulges are disc‐like structures formed by secular evolutionary processes in galaxies. Similar to spirals, the early‐type disc galaxies (S0‐S0/a) have on average relatively exponential bulges with Sersic index n < 2, and 56 per cent of them show disc‐like fine structures in the region of the bulge. For some of the galaxies there is also kinematic evidence of pseudo‐bulges. If S0‐S0/a galaxies were once spirals, stripped of their gas, then redistributed gas and star formation in the disc would be a natural explanation for all pseudo‐bulges in the Hubble sequence. However, it is difficult to explain how the bulges of S0 galaxies, which typically include about 30 per cent of the total galaxy mass, were formed by secularly induced central star formation. A more likely explanation is that pseudo‐bulges in barred early‐type galaxies are a combination of secularly induced star formation and the central steepening of the old stellar distribution. Bulges in non‐barred early‐type galaxies could be either classical merger‐built bulges, or pseudo‐bulges formed by similar processes as in barred galaxies, but in response to massive ovals or lenses (70 per cent of S0‐S0/a galaxies have ovals/lenses). Observational support for the outlined picture comes from the fact that bars in early‐type galaxies seem more evolved: their bars are long and massive and frequently (40 per cent) have ansae morphologies. In this scenario it would be possible also to explain why barred early‐type galaxies (preferentially pseudobulges) have slightly smaller B/T flux ratios than the non‐barred early‐type galaxies (mostly classical bulges).