Browsing by Author "Kaviraj, S."

Now showing items 61-80 of 99

    • Minor-merger-driven growth of early-type galaxies over the last 8 billion years 

      Kaviraj, S.; Crockett, R.M.; Silk, J.; Ellis, R.S.; Yi, S.K.; O'Connell, R.W.; Windhorst, R.; Whitmore, B.C. (Cambridge University Press, 2011-09)
      We summarise recent progress in understanding the star formation activity in early-type galaxies (ETGs), using recent studies that leverage photometry in the rest-frame ultraviolet (UV) wavelengths. While classically thought ...

    • Newborn spheroids at high redshift : When and how did the dominant, old stars in today's massive galaxies form? 

      Kaviraj, S.; Silk, J.; Ellis, R.S.; Cohen, S.; Windhorst, R.A.; Peirani, S.; O'Connell, R.W.; Whitmore, B.C.; Ryan Jr., R.E.; Hathi, N.P.; Dopita, M.A.; Frogel, J.A.; Dekel, A. (2013-01-11)
      We study ~330 massive (M > 10M), newborn spheroidal galaxies (SGs) around the epoch of peak star formation (1 <z <3) to explore the high-redshift origin of SGs and gain insight into when and how the old stellar populations ...

    • Normal black holes in bulge-less galaxies: the largely quiescent, merger-free growth of black holes over cosmic time 

      Martin, G.; Kaviraj, S.; Volonteri, M.; Simmons, B. D.; Devriendt, J. E. G.; Lintott, C. J.; Smethurst, R. J.; Dubois, Y.; Pichon, C. (2018-05-11)
      Understanding the processes that drive the formation of black holes (BHs) is a key topic in observational cosmology. While the observed M BH-M Bulge correlation in bulge-dominated galaxies is thought to be produced by major ...

    • Observational evidence for AGN feedback in early-type galaxies 

      Schawinski, K.; Thomas, D.; Sarzi, M.; Maraston, C.; Kaviraj, S.; Silk, J.; Joo, S-J.; Yi, S.K. (2007)
      A major amendment in recent models of hierarchical galaxy formation is the inclusion of so-called active galactic nucleus (AGN) feedback. The energy input from an active central massive black hole is invoked to suppress ...

    • On the formation of massive galaxies : A simultaneous study of number density, size and intrinsic colour evolution in GOODS 

      Ferreras, I.; Lisker, T.; Pasquali, A.; Khochfar, S.; Kaviraj, S. (2009-07-01)
      The evolution of number density, size and intrinsic colour is determined for a volume-limited sample of visually classified early-type galaxies selected from the Hubble Space Telescope/Advanced Camera for Surveys images ...

    • On the globular cluster formation history of NGC 5128 

      Kaviraj, S.; Ferreras, I.; Yoon, S.-J.; Yi, S.K. (2005-09-01)
      We deduce the globular cluster formation history of the nearby elliptical galaxy, NGC 5128, by using a chemical enrichment model to accurately reproduce its observed metallicity distribution function (MDF). We derive the ...

    • The origin of low-surface-brightness galaxies in the dwarf regime 

      Jackson, R. A.; Martin, G.; Kaviraj, S.; Ramsøy, M.; Devriendt, J. E. G.; Sedgwick, T.; Laigle, C.; Choi, H.; Beckmann, R. S.; Volonteri, M.; Dubois, Y.; Pichon, C.; Yi, S. K.; Slyz, A.; Kraljic, K.; Kimm, T.; Peirani, S.; Baldry, I. (2021-01-13)
      Low-surface-brightness galaxies (LSBGs) -- defined as systems that are fainter than the surface-brightness limits of past wide-area surveys -- form the overwhelming majority of galaxies in the dwarf regime (M* < 10^9 MSun). ...

    • A panchromatic catalog of early-type galaxies at intermediate redshift in the Hubble Space Telescope wide field camera 3 early release science field 

      Rutkowski, M.J.; Cohen, S.H.; Windhorst, R.A.; Kaviraj, S.; Crockett, R.M.; Silk, J.; O'Connell, R.W.; Hathi, N.P.; McCarthy, P.J.; Ryan Jr., R.E.; Koekemoer, A.; Bond, H.E.; Whitmore, B.C.; Yan, H.; Kimble, R.A.; Balick, B.; Calzetti, D.; Disney, M.J.; Dopita, M.A.; Frogel, J.A.; Hall, D.N.B.; Holtzman, J. A.; Paresce, F.; Saha, A.; Trauger, J.T.; Walker, A.R.; Young, E.T. (2012-03-01)
      In the first of a series of forthcoming publications, we present a panchromatic catalog of 102 visually selected early-type galaxies (ETGs) from observations in the Early Release Science (ERS) program with the Wide Field ...

    • Peculiar early-type galaxies in the Sloan Digital Sky Survey Stripe82 

      Kaviraj, S. (2010-07-01)
      We explore the properties of 'peculiar' early-type galaxies (ETGs) in the local Universe that show (faint) morphological signatures of recent interactions such as tidal tails, shells and dust lanes. Standard-depth (∼51-s ...

    • Population statistics of intermediate-mass black holes in dwarf galaxies using the NEWHORIZON simulation 

      Beckmann, R. S.; Dubois, Y.; Volonteri, M.; Dong-Páez, C. A.; Trebitsch, M.; Devriendt, J.; Kaviraj, S.; Kimm, T.; Peirani, S. (2023-08-01)
      While it is well established that supermassive black holes (SMBHs) coevolve with their host galaxy, it is currently less clear how lower-mass black holes, so-called intermediate-mass black holes (IMBHs), evolve within their ...

    • A possible signature of the influence of tidal perturbations in dwarf galaxy scaling relations 

      Watkins, A. E.; Salo, H.; Kaviraj, S.; Collins, C. A.; Knapen, J. H.; Venhola, A.; Román, J. (2023-03-02)
      Dwarf galaxies are excellent cosmological probes, because their shallow potential wells make them very sensitive to the key processes that drive galaxy evolution, including baryonic feedback, tidal interactions, and ram ...

    • Preparing for low surface brightness science with the Vera C. Rubin Observatory: Characterisation of tidal features from mock images 

      Martin, G.; Bazkiaei, A. E.; Spavone, M.; Iodice, E.; Mihos, J. C.; Montes, M.; Benavides, J. A.; Brough, S.; Carlin, J. L.; Collins, C. A.; Duc, P. A.; Gómez, F. A.; Galaz, G.; Hernández-Toledo, H. M.; Jackson, R. A.; Kaviraj, S.; Knapen, J. H.; Martínez-Lombilla, C.; McGee, S.; O'Ryan, D.; Prole, D. J.; Rich, R. M.; Román, J.; Shah, E. A.; Starkenburg, T. K.; Watkins, A. E.; Zaritsky, D.; Laigle, C.; Pichon, C.; Armus, L.; Bianconi, M.; Buitrago, F.; Busá, I.; Davis, F.; Demarco, R.; Desmons, A.; García, P.; Graham, A. W.; Holwerda, B.; Hon, D. S. -H.; Khalid, A.; Klehammer, J.; Klutse, D. Y.; Lazar, I.; Nair, P.; Noakes-Kettel, E. A.; Rutkowski, M.; Saha, K.; Sahu, N.; Sola, E.; Vázquez-Mata, J. A.; Vera-Casanova, A.; Yoon, I. (2022-06-01)
      Tidal features in the outskirts of galaxies yield unique information about their past interactions and are a key prediction of the hierarchical structure formation paradigm. The Vera C. Rubin Observatory is poised to deliver ...

    • Probing quasar shutdown timescales with Hanny's Voorwerp 

      Evans, D.A.; Schawinski, K.; Virani, S.; Urry, C.M.; Keel, W.C.; Natarajan, P.; Lintott, C.J.; Manning, A.; Coppi, P.; Kaviraj, S.; Bamford, S.P.; Józsa, G.I.G.; Garrett, M.; Van Arkel, H.; Gay, P.; Fortson, L. (American Institute of Physics (AIP), 2012)
      Galaxy formation is significantly modulated by energy output from supermassive black holes at the centers of galaxies which grow in highly efficient luminous quasar phases. The timescale on which black holes transition ...

    • Radio AGN in nearby dwarf galaxies: the important role of AGN in dwarf-galaxy evolution 

      Davis, F.; Kaviraj, S.; Hardcastle, M. J.; Martin, G.; Jackson, R. A.; Kraljic, K.; Malek, K.; Peirani, S.; Smith, D. J. B.; Volonteri, M.; Wang, L. (2022-02-04)
      We combine deep optical and radio data, from the Hyper Suprime-Cam and the Low-Frequency Array (LOFAR) respectively, to study 78 radio AGN in nearby (z < 0.5) dwarf galaxies. Comparison to a control sample, matched in ...

    • Radio Galaxy Zoo : host galaxies and radio morphologies derived from visual inspection 

      Banfield, J. K.; Wong, O. I.; Willett, K. W.; Norris, R. P.; Rudnick, L.; Shabala, S. S.; Simmons, B. D.; Snyder, C.; Garon, A.; Seymour, N.; Middelberg, E.; Andernach, H.; Lintott, C. J.; Jacob, K.; Kapinska, A. D.; Mao, M. Y.; Masters, K. L.; Jarvis, M. J.; Schawinski, K.; Paget, E.; Simpson, R.; Klockner, H. R.; Bamford, S.; Burchell, T.; Chow, K. E.; Cotter, G.; Fortson, L.; Heywood, I.; Jones, T. W.; Kaviraj, S.; Lopez-Sanchez, A. R.; Maksym, W. P.; Polsterer, K.; Borden, K.; Hollow, R. P.; Whyte, L. (2015-11-01)
      We present results from the first twelve months of operation of Radio Galaxy Zoo, which upon completion will enable visual inspection of over 170,000 radio sources to determine the host galaxy of the radio emission and the ...

    • Recent star formation in high-redshift early-type galaxies : Insights from the rest-frame UV 

      Kaviraj, S.; Khochfar, S.; Schawinski, K.; Silk, J.; Yi, S.K.; Gawiser, E.; Van Dokkum, P.G. (2007-06)
      We combine deep UBV RIzJK photometry from the MUSYC survey with redshifts from the COMBO-17 survey to study the rest-frame ultraviolet (UV) properties of 674 high-redshift (0.5 <z <1) early-type galaxies, drawn from the ...

    • The role of environment on the formation of early-type galaxies 

      Rogers, B.; Ferreras, I.; Kaviraj, S.; Pasquali, A.; Bernardi, M.; Lahav, O. (2010-06-01)
      The effect of environment on galaxy formation poses one of the best constraints on the interplay between mass assembly and star formation in galaxies. We present here a detailed study of the stellar populations of a ...

    • The role of major mergers in the size growth of intermediate-mass spheroids 

      Kaviraj, S.; Huertas-Company, M.; Cohen, S.; Peirani, S.; Windhorst, R. A.; O'Connell, R. W.; Silk, J.; Dopita, M. A.; Hathi, N. P.; Koekemoer, A. M.; Mei, S.; Rutkowski, M.; Ryan, R. E.; Shankar, F. (2014-09-11)
      We study of the role of ‘major’ mergers (mass ratios >1: 4) in driving size growth in high-redshift (1 < z < 2) spheroidal galaxies (SGs) with stellar masses between 109.5 and 1010.7 M⊙. This is a largely unexplored mass ...

    • The role of mergers and interactions in driving the evolution of dwarf galaxies over cosmic time 

      Martin, G.; Jackson, R. A.; Kaviraj, S.; Choi, H.; Devriendt, J. E. G.; Dubois, Y.; Kimm, T.; Kraljic, K.; Peirani, S.; Pichon, C.; Volonteri, M.; Yi, S. K. (2020-11-07)
      Dwarf galaxies (M⋆ < 109 M☉) are key drivers of mass assembly in high-mass galaxies, but relatively little is understood about the assembly of dwarf galaxies themselves. Using the NEWHORIZON cosmological simulation (∼40 ...

    • The role of mergers in driving morphological transformation over cosmic time 

      Martin, G.; Kaviraj, S.; Devriendt, J. E. G.; Dubois, Y.; Pichon, C. (2018-10-01)
      Understanding the processes that trigger morphological transformation is central to understanding how and why the Universe transitions from being disc-dominated at early epochs to having the morphological mix that is ...