Browsing by Author "Comeron, Sebastien"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    H alpha kinematics of S(4)G spiral galaxies - I. NGC 864
    (Oxford University Press, 2012-12-21) Erroz-Ferrer, Santiago; Knapen, Johan H.; Font, Joan; Beckman, John E.; Falcon-Barroso, Jesus; Ramon Sanchez-Gallego, Jose; Athanassoula, E.; Bosma, Albert; Gadotti, Dimitri A.; Munoz-Mateos, Juan Carlos; Sheth, Kartik; Buta, Ronald J.; Comeron, Sebastien; Gil de Paz, Armando; Hinz, Joannah L.; Ho, Luis C.; Kim, Taehyun; Laine, Jarkko; Laurikainen, Eija; Madore, Barry F.; Menendez-Delmestre, Karin; Mizusawa, Trisha; Regan, Michael W.; Salo, Heikki; Seibert, Mark; Instituto de Astrofisica de Canarias; Universidad de la Laguna; Centre National de la Recherche Scientifique (CNRS); CNRS - National Institute for Earth Sciences & Astronomy (INSU); UDICE-French Research Universities; Aix-Marseille Universite; European Southern Observatory; National Radio Astronomy Observatory (NRAO); California Institute of Technology; University of Alabama Tuscaloosa; Korea Astronomy & Space Science Institute (KASI); Complutense University of Madrid; University of Arizona; Carnegie Institution for Science; Seoul National University (SNU); University of Oulu; University of Turku; Universidade Federal do Rio de Janeiro; Space Telescope Science Institute
    We present a study of the kinematics of the isolated spiral galaxy NGC 864, using H alpha Fabry-Perot data obtained with the Galaxy H alpha Fabry-Perot System (GH alpha FaS) instrument at the William Herschel Telescope in La Palma, complemented with images at 3.6 mu m, in the R band and in H alpha filter, and integral-field spectroscopic data. The resulting data cubes and velocity maps allow the study of the kinematics of the galaxy, including in-depth investigations of the rotation curve, velocity moment maps, velocity residual maps, gradient maps and position-velocity diagrams. We find asymmetries in the velocity field in the bar zone, caused by non-circular motions, probably in response to the potential of the bar. We also find a flat-profile bar, in agreement with the strong bar, with the grand design spiral pattern, and with the gap between the ends of the bar and the start of the spiral arms. We quantify the rate of massive star formation, which is concentrated in the two spiral arms.
  • Thumbnail Image
    Item
    MID-INFRARED GALAXY MORPHOLOGY FROM THE SPITZER SURVEY OF STELLAR STRUCTURE IN GALAXIES (S(4)G): THE IMPRINT OF THE DE VAUCOULEURS REVISED HUBBLE-SANDAGE CLASSIFICATION SYSTEM AT 3.6 mu m
    (IOP Publishing, 2010-08-31) Buta, Ronald J.; Sheth, Kartik; Regan, Michael; Hinz, Joannah L.; Gil de Paz, Armando; Menendez-Delmestre, Karin; Munoz-Mateos, Juan-Carlos; Seibert, Mark; Laurikainen, Eija; Salo, Heikki; Gadotti, Dimitri A.; Athanassoula, E.; Bosma, Albert; Knapen, Johan H.; Ho, Luis C.; Madore, Barry F.; Elmegreen, Debra M.; Masters, Karen L.; Comeron, Sebastien; Aravena, Manuel; Kim, Taehyun; University of Alabama Tuscaloosa; National Radio Astronomy Observatory (NRAO); Space Telescope Science Institute; University of Arizona; Complutense University of Madrid; California Institute of Technology; Carnegie Institution for Science; University of Oulu; European Southern Observatory; Centre National de la Recherche Scientifique (CNRS); UDICE-French Research Universities; Aix-Marseille Universite; Instituto de Astrofisica de Canarias; Universidad de la Laguna; Vassar College; University of Portsmouth; Korea Astronomy & Space Science Institute (KASI); Seoul National University (SNU)
    Spitzer Space Telescope Infrared Array Camera imaging provides an opportunity to study all known morphological types of galaxies in the mid-IR at a depth significantly better than ground-based near-infrared and optical images. The goal of this study is to examine the imprint of the de Vaucouleurs classification volume in the 3.6 mu m band, which is the best Spitzer waveband for galactic stellar mass morphology owing to its depth and its reddening-free sensitivity mainly to older stars. For this purpose, we have prepared classification images for 207 galaxies from the Spitzer archive, most of which are formally part of the Spitzer Survey of Stellar Structure in Galaxies (S(4)G), a Spitzer post-cryogenic ("warm") mission Exploration Science Legacy Program survey of 2331 galaxies closer than 40 Mpc. For the purposes of morphology, the galaxies are interpreted as if the images are blue light, the historical waveband for classical galaxy classification studies. We find that 3.6 mu m classifications are well correlated with blue-light classifications, to the point where the essential features of many galaxies look very similar in the two very different wavelength regimes. Drastic differences are found only for the most dusty galaxies. Consistent with a previous study by Eskridge et al., the main difference between blue-light and mid-IR types is an approximate to 1 stage interval difference for S0/a to Sbc or Sc galaxies, which tend to appear "earlier" in type at 3.6 mu m due to the slightly increased prominence of the bulge, the reduced effects of extinction, and the reduced (but not completely eliminated) effect of the extreme population I stellar component. We present an atlas of all of the 207 galaxies analyzed here and bring attention to special features or galaxy types, such as nuclear rings, pseudobulges, flocculent spiral galaxies, I0 galaxies, double-stage and double-variety galaxies, and outer rings, that are particularly distinctive in the mid-IR.
  • Thumbnail Image
    Item
    THE THICK DISK IN THE GALAXY NGC 4244 FROM S(4)G IMAGING
    (IOP Publishing, 2011-02-07) Comeron, Sebastien; Knapen, Johan H.; Sheth, Kartik; Regan, Michael W.; Hinz, Joannah L.; Gil de Paz, Armando; Menendez-Delmestre, Karin; Munoz-Mateos, Juan-Carlos; Seibert, Mark; Kim, Taehyun; Athanassoula, E.; Bosma, Albert; Buta, Ronald J.; Elmegreen, Bruce G.; Ho, Luis C.; Holwerda, Benne W.; Laurikainen, Eija; Salo, Heikki; Schinnerer, Eva; Korea Astronomy & Space Science Institute (KASI); Instituto de Astrofisica de Canarias; Universidad de la Laguna; National Radio Astronomy Observatory (NRAO); California Institute of Technology; Space Telescope Science Institute; University of Arizona; Complutense University of Madrid; Carnegie Institution for Science; Seoul National University (SNU); Centre National de la Recherche Scientifique (CNRS); UDICE-French Research Universities; Aix-Marseille Universite; University of Alabama Tuscaloosa; International Business Machines (IBM); University of Cape Town; University of Oulu; University of Turku; Max Planck Society
    If thick disks are ubiquitous and a natural product of disk galaxy formation and/or evolution processes, all undisturbed galaxies that have evolved during a significant fraction of a Hubble time should have a thick disk. The late-type spiral galaxy NGC 4244 has been reported as the only nearby edge-on galaxy without a confirmed thick disk. Using data from the Spitzer Survey of Stellar Structure in Galaxies (S(4)G) we have identified signs of two disk components in this galaxy. The asymmetries between the light profiles on both sides of the mid-plane of NGC 4244 can be explained by a combination of the galaxy not being perfectly edge-on and a certain degree of opacity of the thin disk. We argue that the subtlety of the thick disk is a consequence of either a limited secular evolution in NGC 4244, a small fraction of stellar material in the fragments which built the galaxy, or a high amount of gaseous accretion after the formation of the galaxy.
  • Thumbnail Image
    Item
    THE UNUSUAL VERTICAL MASS DISTRIBUTION OF NGC 4013 SEEN THROUGH THE SPITZER SURVEY OF STELLAR STRUCTURE IN GALAXIES (S(4)G)
    (IOP Publishing, 2011-08-17) Comeron, Sebastien; Elmegreen, Bruce G.; Knapen, Johan H.; Sheth, Kartik; Hinz, Joannah L.; Regan, Michael W.; Gil de Paz, Armando; Munoz-Mateos, Juan-Carlos; Menendez-Delmestre, Karin; Seibert, Mark; Kim, Taehyun; Mizusawa, Trisha; Laurikainen, Eija; Salo, Heikki; Laine, Jarkko; Athanassoula, E.; Bosma, Albert; Buta, Ronald J.; Gadotti, Dimitri A.; Ho, Luis C.; Holwerda, Benne; Schinnerer, Eva; Zaritsky, Dennis; Korea Astronomy & Space Science Institute (KASI); International Business Machines (IBM); Instituto de Astrofisica de Canarias; Universidad de la Laguna; National Radio Astronomy Observatory (NRAO); University of Arizona; Space Telescope Science Institute; Complutense University of Madrid; Carnegie Institution for Science; University of Oulu; University of Turku; Centre National de la Recherche Scientifique (CNRS); UDICE-French Research Universities; Aix-Marseille Universite; University of Alabama Tuscaloosa; European Southern Observatory; European Space Agency; Max Planck Society
    NGC 4013 is a nearby Sb edge-on galaxy known for its "prodigious" Hi warp and its "giant" tidal stream. Previous work on this unusual object shows that it cannot be fitted satisfactorily by a canonical thin+thick disk structure. We have produced a new decomposition of NGC 4013, considering three stellar flattened components (thin+thick disk plus an extra and more extended component) and one gaseous disk. All four components are considered to be gravitationally coupled and isothermal. To do so, we have used the 3.6 mu m images from the Spitzer Survey of Stellar Structure in Galaxies. We find evidence for NGC 4013 indeed having a thin and a thick disk and an extra flattened component. This smooth and extended component (scale height z(EC) similar to 3 kpc) could be interpreted as a thick disk or as a squashed ellipsoidal halo and contains similar to 20% of the total mass of all three stellar components. We argue it is unlikely to be related to the ongoing merger or due to the off-plane stars from a warp in the other two disk components. Instead, we favor a scenario in which the thick disk and the extended component were formed in a two-stage process, in which an initially thick disk has been dynamically heated by a merger soon enough in the galaxy history to have a new thick disk formed within it.