Browsing by Author "Kaviraj, S."

Now showing items 41-60 of 99

    • Galaxy Zoo: the fraction of merging galaxies in the SDSS and their morphologies 

      Darg, D.W.; Kaviraj, S.; Lintott, C.J.; Silk, J.; Schawinski, K.; Sarzi, M.; Bamford, S.; Proctor, R.; Andreescu, D.; Murray, P.; Nichol, R.C.; Thomas, D.; Raddick, M.J.; Szalay, A.S.; Vandenberg, J.; Slosar, A. (2010)
      We present the largest, most homogeneous catalogue of merging galaxies in the nearby Universe obtained through the Galaxy Zoo project – an interface on the World Wide Web enabling large-scale morphological classification ...

    • Galaxy Zoo: the fundamentally different co-evolution of supermassive black holes and their early- and late-type host galaxies 

      Schawinski, K.; Urry, C.M.; Virani, S.; Coppi, P.; Bamford, S.; Treister, E.; Lintott, C.; Sarzi, M.; Keel, W.; Kaviraj, S.; Cardamone, C.; Masters, K.L.; Ross, N.P.; Andreescu, D.; Murray, P.; Nichol, R.C.; Raddick, M.J.; Slosar, A.; Szalay, A.; Thomas, D.; Vandenberg, J. (2010)
      We use data from the Sloan Digital Sky Survey and visual classifications of morphology from the Galaxy Zoo project to study black hole growth in the nearby universe (z < 0.05) and to break down the active galactic nucleus ...

    • Galaxy Zoo: The properties of merging galaxies in the nearby Universe - Local environments, colours, masses, star formation rates and AGN activity 

      Darg, D.W.; Kaviraj, S.; Lintott, C.J.; Silk, J.; Schawinski, K.; Sarzi, M.; Bamford, S.; Andreescu, D.; Murray, P.; Nichol, R.C.; Thomas, D.; Raddick, M.J.; Szalay, A.S.; Vandenberg, J.; Slosar, A. (2010)
      Following the study of Darg et al., we explore the environments, optical colours, stellar masses, star formation and active galactic nucleus activity in a sample of 3003 pairs of merging galaxies drawn from the Sloan Digital ...

    • Galex-derived residual star formation history of elliptical galaxies 

      Yi, S.K.; Kaviraj, S.; Schawinski, K.; Khochfar, S. (EDP Sciences, 2007)
      Bright early-type galaxies are still forming stars at low-level residual star formation (RSF) mode. The GALEX UV satellite has detected excessive UV flux in > 30% of our volume-limited sample of ∼10 galaxies. The RSF galaxy ...

    • GALICS II : The [ α/Fe]-mass relation in elliptical galaxies 

      Pipino, A.; Devriendt, J.E.G.; Silk, J.; Kaviraj, S.; Thomas, D. (2009-10-03)
      Aims. We test whether the mass-and σ-[α/Fe] relations in the stellar populations of early-type galaxies can be reproduced by a cosmologically motivated assembly history for spheroids.Methods. We implement a detailed treatment ...

    • Globular clusters as probes of galaxy evolution : NGC 5128 

      Yi, S.K.; Kaviraj, S.; Yoon, S.-J.; Peng, E.; Ford, H. (2004-04-21)
      We present the results of our analysis of the photometric data of globular clusters in the elliptical galaxy NGC 5128 (Cen A). We show that the integrated colour U - B can be an effective metallicity indicator for simple ...

    • H-ATLAS/GAMA : The nature and characteristics of optically red galaxies detected at submillimetre wavelengths 

      Dariush, A.; Dib, S.; Hony, S.; Smith, D. J. B.; Zhukovska, S.; Dunne, L.; Eales, S.; Andrae, E.; Baes, M.; Baldry, I.; Bauer, A.; Bland-Hawthorn, J.; Brough, S.; Bourne, N.; Cava, A.; Clements, D.; Cluver, M.; Cooray, A.; Zotti, G. De; Driver, S.; Grootes, M. W.; Hopkins, A. M.; Hopwood, R.; Kaviraj, S.; Kelvin, L.; Lara-Lopez, M. A.; Liske, J.; Loveday, J.; Maddox, S.; Madore, B.; Michalowski, M. J.; Pearson, C.; Popescu, C.; Robotham, A.; Rowlands, K.; Seibert, M.; Shabani, F.; Smith, M. W. L.; Taylor, E. N.; Tuffs, R.; Valiante, E.; Virdee, J. S. (2016-02-21)
      We combine Herschel/SPIRE sub-millimeter (submm) observations with existing multi-wavelength data to investigate the characteristics of low redshift, optically red galaxies detected in submm bands. We select a sample of ...

    • Herschel -ATLAS/GAMA : Dusty early-type galaxies and passive spirals 

      Rowlands, K.; Dunne, L.; Maddox, S.; Bourne, N.; Bamford, S. P.; Smith, Daniel; Dye, S.; Rigby, E.E.; Gomez, H.L.; Eales, S.A.; Kaviraj, S.; Dariush, A.; Hopwood, R.; Brough, S.; Hopkins, A. M.; Charlot, S.; da Cunha, E.; Driver, S. P.; Kelvin, L.; Robotham, A.; Nichol, R.C.; Sansom, A. E.; Popescu, C.C.; Sharp, R.; Temi, P.; van der Werf, P.; Baes, M.; Fritz, J.; Cava, A.; Cooray, A.; Croom, S. M.; de Zotti, G.; Rodighiero, G.; Ibar, E.; Ivison, R.J.; Norberg, P.; Liske, J.; Loveday, J.; Madore, B.; Seibert, M.; Tuffs, R. J. (2012)
      We present the dust properties and star-formation histories of local submillimetre-selected galaxies, classified by optical morphology. Most of the galaxies are late types and very few are early types. The early-type ...

    • Herschel -ATLAS/GAMA : Dusty early-type galaxies and passive spirals 

      Rowlands, K.; Dunne, L.; Maddox, S.; Bourne, N.; Gomez, H.L.; Kaviraj, S.; Bamford, S. P.; Brough, S.; Charlot, S.; da Cunha, E.; Driver, S. P.; Eales, S.~A.; Hopkins, A. M.; Kelvin, L.; Nichol, R.C.; Sansom, A. E.; Sharp, R.; Smith, Daniel; Temi, P.; van der Werf, P.; Baes, M.; Cava, A.; Cooray, A.; Croom, S. M.; Dariush, A.; de Zotti, G.; Dye, S.; Fritz, J.; Hopwood, R.; Ibar, E.; Ivison, R.J.; Liske, J.; Loveday, J.; Madore, B.; Norberg, P.; Popescu, C.; Rigby, E.; Robotham, A.; Rodighiero, G.; Seibert, M.; Tuffs, R. J. (2012-01)
      We present the dust properties and star formation histories of local submillimetre-selected galaxies, classified by optical morphology. Most of the galaxies are late types and very few are early types. The early-type ...

    • A Herschel*-ATLAS study of dusty spheroids : Probing the minor-merger process in the local Universe 

      Kaviraj, S.; Rowlands, K.; Alpaslan, M.; Dunne, L.; Ting, Y. S.; Bureau, M.; Shabala, S.; Lintott, C.J.; Smith, Daniel; Agius, N.; Auld, R.; Baes, M.; Bourne, N.; Cava, A.; Clements, D. L.; Cooray, A.; Dariush, A.; de Zotti, G.; Driver, S. P.; Eales, S.; Hopwood, R.; Hoyos, C.; Ibar, E.; Maddox, S.; Michalowski, M. J.; Sansom, A. E.; Smith, M.; Valiante, E. (2013-10)
      We use multiwavelength (0.12-500 μm) photometry from Herschel-ATLAS, WISE, UKIDSS, SDSS and GALEX to study 23 nearby spheroidal galaxies with prominent dust lanes (DLSGs). DLSGs are considered to be remnants of recent minor ...

    • Herschel-atlas galaxy counts and high-redshift luminosity functions : The formation of massive early-type galaxies 

      Lapi, A.; González-Nuevo, J.; Fan, L.; Bressan, A.; de Zotti, G.; Danese, L.; Buttiglione, S.; Negrello, M.; Hopwood, R.; Serjeant, S.; Dunne, L.; Maddox, S.; Rigby, E.; Eales, S.; Auld, R.; Dariush, A.; Dye, S.; Kaviraj, S.; Pascale, E.; Pohlen, M.; Baes, M.; Fritz, J.; Bonfield, D.G.; Jarvis, M.J.; Smith, Daniel; Cava, A.; Clements, D. L.; Dariush, A.; Hopwood, R.; Cooray, A.; Wardlow, J.; Herranz, D.; López-Caniego, M.; Ibar, E.; Ivison, R.; Michałowski, M. J.; Jarvis, M.J.; Massardi, M.; Rodighiero, G.; Temi, P.; Van Der Werf, P. (2011)
      Exploiting the Herschel Astrophysical Terahertz Large Area Survey Science Demonstration Phase survey data, we have determined the luminosity functions (LFs) at rest-frame wavelengths of 100 and 250 μm and at several redshifts ...

    • The Horizon-AGN simulation: evolution of galaxy properties over cosmic time 

      Kaviraj, S.; Laigle, C.; Kimm, T.; Devriendt, J. E. G.; Dubois, Y.; Pichon, C.; Slyz, A.; Chisari, E.; Peirani, S. (2017-06-01)
      We compare the predictions of Horizon-AGN, a hydro-dynamical cosmological simulation that uses an adaptive mesh refinement code, to observational data in the redshift range 0 < z < 6. We study the reproduction, by the ...

    • The Hubble Space Telescope wide field camera 3 early release science data : Panchromatic faint object counts for 0.2-2 μm wavelength 

      Windhorst, R.A.; Cohen, S.H.; Mechtley, M.; Rutkowski, M.J.; Hathi, N.P.; McCarthy, P.J.; Seibert, M.; Ryan, R.E.; Yan, H.; Baldry, I.K.; Driver, S.P.; Hill, D.T.; Kelvin, L.S.; Robotham, A.S.G.; Frogel, J.A.; Koekemoer, A.M.; Bond, H.E.; Bushouse, H.; MacKenty, J.W.; Mutchler, M.; Whitmore, B.C.; O'Connell, R.W.; Straughn, A.N.; Kimble, R.A.; Tuffs, R.J.; Balick, B.; Calzetti, D.; Silk, J.I.; Crockett, M.; Kaviraj, S.; Disney, M.J.; Dopita, M.A.; Hall, D.N.B.; Holtzman, J. A.; Paresce, F.; Saha, A.; Trauger, J.T.; Walker, A.R.; Young, E.T. (2011-04-01)
      We describe the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) Early Release Science (ERS) observations in the Great Observatories Origins Deep Survey (GOODS) South field. The new WFC3 ERS data provide calibrated, ...

    • Identifying the progenitor set of present-day early-type galaxies : A view from the standard model 

      Kaviraj, S.; Ferreras, I.; Devriendt, J.E.G.; Silk, J.; Yi, S.K. (2009-08-01)
      We present a comprehensive theoretical study, using a semi-analytical model within the standard LCDM framework, of the photometric properties of the progenitors of present-day early-type galaxies in the redshift range 0 ...

    • Identifying the progenitors of present-day early-type galaxies in observational surveys: correcting `progenitor bias' using the Horizon-AGN simulation 

      Martin, G.; Kaviraj, S.; Devriendt, J.E.G.; Dubois, Y.; Pichon, C.; Laigle, C. (2018-03-01)
      As endpoints of the hierarchical mass-assembly process, the stellar populations of local earlytype galaxies encode the assembly history of galaxies over cosmic time. We useHorizon-AGN, a cosmological hydrodynamical simulation, ...

    • The insignificance of major mergers in driving star formation at z ≃ 2 

      Kaviraj, S.; Silk, J.; Cohen, S.; Windhorst, R.A.; Rutkowski, M.; O'Connell, R.W.; Dopita, M.A.; Dekel, A.; Hathi, N.P.; Straughn, A. (2013-02-01)
      We study the significance of major-merger-driven star formation in the early Universe, by quantifying the contribution of this process to the total star formation budget in 80 massive (M* > 1010 M) galaxies at z ≃ 2. ...

    • The limited role of galaxy mergers in driving stellar mass growth over cosmic time 

      Martin, G.; Kaviraj, S.; Devriendt, J.E.G.; Dubois, Y.; Laigle, C.; Pichon, C. (2017-11-21)
      A key unresolved question is the role that galaxy mergers play in driving stellar mass growth over cosmic time. Recent observational work hints at the possibility that the overall contribution of `major' mergers (mass ...

    • The look-back time evolution of far-ultraviolet flux from the brightest cluster elliptical galaxies at z <0.2 

      Ree, C.H.; Lee, Y.-W.; Yi, S.K.; Yoon, S.-J.; Sohn, Y.-J.; Rhee, J.; Sheen, Y.-K.; Rich, R.M.; Deharveng, J.-M.; Boselli, A.; Donas, J.; Milliard, B.; Kaviraj, S.; Schawinski, K.; Rey, S.-C.; Seibert, M.; Wyder, T.K.; Barlow, T.A.; Forster, K.; Friedman, P.G.; Martin, D.C.; Morrissey, P.; Small, T.; Bianchi, L.; Heckman, T.M.; Szalay, A.S.; Madore, B.F.; Neff, S.G.; Schiminovich, D.; Welsh, B.Y. (2007-12-01)
      We present the GALEXUV photometry of the elliptical galaxies in Abell clusters at moderate redshifts (z <0.2) for the study of the look-back time evolution of the UV upturn phenomenon. The brightest elliptical galaxies (M ...

    • Major mergers are not significant drivers of star formation or morphological transformation around the epoch of peak cosmic star formation 

      Lofthouse, E. K.; Kaviraj, S.; Conselice, C. J.; Mortlock, A.; Hartley, W. (2017-03-01)
      We investigate the contribution of major mergers (mass ratios > 1 : 5) to stellar mass growth and morphological transformations around the epoch of peak cosmic star formation (z ∼ 2). We visually classify a complete sample ...

    • Massive spheroids can form in single minor mergers 

      Jackson, R. A.; Martin, G.; Kaviraj, S.; Laigle, C.; Devriendt, J. E. G.; Dubois, Y.; Pichon, C. (2019-11-01)
      Understanding how rotationally supported discs transform into dispersion-dominated spheroids is central to our comprehension of galaxy evolution. Morphological transformation is largely merger-driven. While major mergers ...