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Specific Star Formation Rate Profiles in Nearby Spiral Galaxies: Quantifying the Inside-Out Formation of Disks
We present specific star formation rate (sSFR) radial profiles for asample of 161 relatively face-on spiral galaxies from the GALEX Atlas ofNearby Galaxies. The sSFR profiles are derived from GALEX and 2MASS(FUV-K) color profiles after a proper SFR calibration of the UVluminosity and K-band mass-to-light ratio are adopted. The (FUV-K)profiles were first corrected for foreground Galactic extinction andlater for internal extinction using the ratio of the total-infrared(TIR) to FUV emission. For those objects where TIR-to-FUV ratio radialprofiles were not available, the (FUV-NUV) color profiles were used as ameasure of the UV slope. The sSFR radial gradients derived from theseprofiles allow us to quantify the inside-out scenario for the growth ofspiral disks for the first time in the local universe. We find a largedispersion in the slope of the sSFR profiles with a slightly positivemean value, which implies a moderate inside-out disk formation. There isalso a strong dependency of the value of this slope on the luminosityand size of the disks, with large systems showing a uniform, slightlypositive slope in almost all cases and low-luminosity small disksshowing a large dispersion with both positive and negative large values.While a majority of the galaxies can be interpreted as forming starsgradually either from inside out or from outside in, a few disks requireepisodes of enhanced recent growth with scale lengths of the SFR (or gasinfall) being significantly larger at present than in the past. We donot find any clear dependence of the sSFR gradient on the environment(local galaxy density or presence of close neighbors).
| A List of New Blue Galaxies. III
A list of new fifty-eight blue galaxies identified in three 103aDspectroscopic plates, with 3-image UBV filters obtained with the 48-inSchmidt Camera of Mount Palomar is presented. The fields are centered at(00h 00m, +6o 00'), (00h00m, -12o 00'), and (00h48m, 00o 00') 1950.0 coordinates. These plateswere originally taken for the observational program of faint blue starsin the regions of the South Galactic Pole, by Haro & Luyten (1965).
| The morphological catalogue of galaxies equatorial survey
We present 865 redshifts of galaxies located in the equatorial stripdelta between -17.5 deg and -2.5 deg in the right ascension rangebetween 20 h and 5 h. Redshifts have been obtained for the completesample of all 833 galaxies in the Morphological Catalog of Galaxies withmagnitudes brighter than m = 14.5 (corresponding approximately tom(Zwicky) = 15.0). This sample also includes three galaxies from othersources with more reliable magnitudes, satisfying this limit, and 29fainter galaxies, usually companions of the galaxies in the magnitudelimited sample. Our maps of a very large volume of nearby spacedemonstrate a variety of coherent large scale structures which includelarge voids, 20-50/h Mpc in diameter and large walls at least 70/h Mpcacross.
| An extragalactic database. I - The Catalogue of Principal Galaxies
The Catalogue of Principal Galaxies is described, which lists equatorialcoordinates (for the equinoxes 1950 and 2000) and cross-identificationsfor 73,197 galaxies. The 40,932 coordinates have standard deviationssmaller than 10 arcsec. A total of 131,601 names from the 38 most commonsources are listed. In addition, mean data for each object are givenwhen available: 49,102 morphological descriptions, 52,954 apparent majorand minor axes, 67,116 apparent magnitudes, 20,046 radial velocities and24,361 position angles. This information was used for facilitatingproper identification. Finally, distribution options are explained.
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