Browsing University of Hertfordshire by Author "Schawinski, K."

Now showing items 1-20 of 36

    • The Chandra COSMOS Survey III : Optical and infrared identification of X-ray point sources 

      Civano, F.; Elvis, M.; Aldcroft, T.; Fruscione, A.; Hao, H.; Lanzuisi, G.; Wright, N.J.; Brusa, M.; Salvato, M.; Bongiorno, A.; Comastri, A.; Zamorani, G.; Cappelluti, N.; Gilli, R.; Lusso, E.; Vignali, C.; Fiore, F.; Capak, P.; Scoville, N.Z.; Cisternas, M.; Kartaltepe, J.; Koekemoer, A. M.; Impey, C.D.; Trump, J.; Mainieri, V.; Miyaji, T.; Lilly, S.; Masters, D.; Puccetti, S.; Schawinski, K.; Urry, M.; Silverman, J. (2012-08-01)
      The Chandra COSMOS Survey (C-COSMOS) is a large, 1.8 Ms, Chandra program that has imaged the central 0.9 deg2 of the COSMOS field down to limiting depths of 1.9×10−16 erg cm−2 s−1 in the soft (0.5–2 keV) band, 7.3×10−16 ...

    • Chandra observations of Galaxy Zoo mergers : Frequency of binary active nuclei in massive mergers 

      Teng, S.H.; Schawinski, K.; Urry, C.M.; Bonning, E.W.; Simmons, B.D.; Darg, D.W.; Kaviraj, S.; Lintott, C.J.; Oh, K.; Cardamone, C.N.; Keel, W.C.; Treister, E. (2012-07-10)
      We present the results from a Chandra pilot study of 12 massive galaxy mergers selected from Galaxy Zoo. The sample includes major mergers down to a host galaxy mass of 1011 M ☉ that already have optical active galactic ...

    • Destruction of molecular gas reservoirs in early-type galaxies by active galactic nucleus feedback 

      Schawinski, K.; Lintott, C.J.; Kaviraj, S.; Silk, J.; Zuntz, J.; Bayet, E.; Thomas, D.; Maraston, C.; Viti, S.; Sarzi, M.; Yi, S.K.; Joo, S-J.; Daddi, E.; Bell, T. (2009)
      Residual star formation at late times in early-type galaxies and their progenitors must be suppressed in order to explain the population of red, passively evolving systems we see today. Likewise, residual or newly accreted ...

    • Do moderate-luminosity active galactic nuclei suppress star formation? 

      Schawinski, K.; Virani, S.; Simmons, B.; Urry, C.M.; Kushkuley, B.; Treister, E.; Kaviraj, S. (2009)
      The growth of supermassive black holes and their host galaxies are thought to be linked, but the precise nature of this symbiotic relationship is still poorly understood. Both observations and simulations of galaxy formation ...

    • The effect of environment on the ultraviolet color-magnitude relation of early-type galaxies 

      Schawinski, K.; Kaviraj, S.; Khochfar, S.; Yoon, S.-J.; Yi, S.K.; Lee, Y.-W.; Deharveng, J.-M.; Boselli, A.; Donas, J.; Milliard, B.; Barlow, T.; Conrow, T.; Forster, K.; Friedman, P.G.; Martin, D.C.; Morrissey, P.; Seibert, M.; Small, T.; Wyder, T.; Neff, S.; Schiminovich, D.; Blanchi, L.; Heckman, T.; Szalay, A.; Madore, B.; Rich, R.M. (2007-12-01)
      We use GALEX near-UV (NUV ) photometry of a sample of early-type galaxies selected in the SDSS (Sloan Digital Sky Survey) to study the UV color-magnitude relation (CMR). NUV - r color is an excellent tracer of even small ...

    • Environment and self-regulation in galaxy formation 

      Thomas, D.; Maraston, C.; Schawinski, K.; Sarzi, M.; Silk, J. (2010)
      The environment is known to affect the formation and evolution of galaxies considerably best visible through the well-known morphology–density relationship. It is less clear, though, whether the environment is equally ...

    • Environment and the epochs of galaxy formation in the SDSS era 

      Thomas, D.; Maraston, C.; Schawinski, K.; Joo, S.-J.; Kaviraj, S.; Sarzi, M.; Yi, S.K. (2006-12-01)
      We analyse a sample of 1,652 elliptical galaxies morphologically selected from the SDSS DR4 with respect to their stellar population properties such as luminosity weighted ages, metallicities and /Fe element abundance ...

    • Galaxy zoo 2 : Detailed morphological classifications for 304,122 galaxies from the sloan digital sky survey 

      Willett, K.W.; Lintott, C.J.; Bamford, S.P.; Masters, K.L.; Simmons, B.D.; Casteels, K.R.V.; Edmondson, E.M.; Fortson, L.F.; Kaviraj, S.; Keel, W.C.; Melvin, T.; Nichol, R.C.; Jordan Raddick, M.; Schawinski, K.; Simpson, R.J.; Skibba, R.A.; Smith, A.M.; Thomas, D. (2013-11-01)
      We present the data release for Galaxy Zoo 2 (GZ2), a citizen science project with more than 16 million morphological classifications of 304,122 galaxies drawn from the Sloan Digital Sky Survey (SDSS).Morphology is a ...

    • Galaxy Zoo : Building the low-mass end of the red sequence with local post-starburst galaxies 

      Wong, O.I.; Schawinski, K.; Kaviraj, S.; Lintott, C.; Darg, D.; Masters, K.L.; Nichol, R.C.; Thomas, D.; Keel, W.C.; Bamford, S.P.; Andreescu, D.; Murray, P.; Raddick, M.J.; Szalay, A.; Vandenberg, J. (2012-02-01)
      We present a study of local post-starburst galaxies (PSGs) using the photometric and spectroscopic observations from the Sloan Digital Sky Survey and the results from the Galaxy Zoo project. We find that the majority of ...

    • Galaxy Zoo : Dust and molecular gas in early-type galaxies with prominent dust lanes 

      Kaviraj, S.; Ting, Y. S.; Bureau, M.; Shabala, S.S.; Crockett, R.M.; Silk, J.; Lintott, C.; Smith, A.; Keel, W.C.; Masters, K.L.; Schawinski, K.; Bamford, S.P. (2012-06-01)
      We explore the properties of dust and associated molecular gas in 352 nearby (0.01 <z <0.07) early-type galaxies (ETGs) with prominent dust lanes, drawn from the Sloan Digital Sky Survey (SDSS). Two-thirds of these 'dusty ...

    • Galaxy Zoo : Dust lane early-type galaxies are tracers of recent, gas-rich minor mergers 

      Shabala, S.S.; Ting, Y. S.; Kaviraj, S.; Lintott, C.; Crockett, R.M.; Silk, J.; Sarzi, M.; Schawinski, K.; Bamford, S.P.; Edmondson, E. (2012-06-01)
      We present the second of two papers concerning the origin and evolution of local early-type galaxies exhibiting dust features. We use optical and radio data to examine the nature of active galactic nucleus (AGN) activity ...

    • 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.; Cardamone, C.N.; Bamford, S.P.; Treister, E.; Lintott, C.J.; Kaviraj, S.; Sarzi, M.; Keel, W.C.; Masters, K.L.; Nichol, R.C.; Thomas, D.; Ross, N.P.; Andreescu, D.; Murray, P.; Raddick, M.J.; Szalay, A.S.; Vandenberg, J.; Slosar, A. (2010-01-01)
      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 Green Peas: discovery of a class of compact extremely star-forming galaxies 

      Cardamone, C.; Schawinski, K.; Sarzi, M.; Bamford, S.; Bennert, N.; Urry, C.M.; Lintott, C.; Keel, W.; Parejko, J.; Nichol, R.C.; Thomas, D.; Andreescu, D.; Murray, P.; Raddick, M.J.; Slosar, A.; Szalay, A.; Vandenberg, J. (2009)
      We investigate a class of rapidly growing emission line galaxies, known as 'Green Peas', first noted by volunteers in the Galaxy Zoo project because of their peculiar bright green colour and small size, unresolved in Sloan ...

    • Galaxy Zoo: a sample of blue early-type galaxies at low redshift 

      Schawinski, K.; Lintott, C.; Kaviraj, S.; Khochfar, S.; Land, K.; Thomas, D.; Bamford, S. P.; Nichol, R.C.; Sarzi, M.; Andreescu, D.; Murray, P.; Raddick, M.J.; Szalay, A.; Vandenberg, J.; Slosar, A.; Yi, S.K. (2009)
      We report the discovery of a population of nearby, blue early-type galaxies with high star formation rates (0.5 < SFR < 50 M⊙ yr−1) . They are identified by their visual morphology as provided by Galaxy Zoo for Sloan Digital ...

    • Galaxy Zoo: Bulgeless galaxies with growing black holes 

      Simmons, B.; Lintott, C.; Kaviraj, S.; Schawinski, K.; Han, A.; Urry, C.M.; Moran, E.C.; Masters, K.L.; Nichol, R.C.; Willett, K.W.; Bamford, S.P. (2013-03)
      The growth of supermassive black holes appears to be driven by galaxy mergers, violent merger-free processes and/or 'secular' processes. In order to quantify the effects of secular evolution on black hole growth, we study ...

    • Galaxy Zoo: evidence for Diverse Star Formation Histories through the Green Valley 

      Smethurst, R. J.; Lintott, C. J.; Simmons, B. D.; Schawinski, K.; Marshall, P. J.; Bamford, S.; Fortson, L.; Kaviraj, S.; Masters, K. L.; Melvin, T.; Nichol, R. C.; Skibba, R. A.; Willett, K. W. (2015-04-17)
      Does galaxy evolution proceed through the green valley via multiple pathways or as a single population? Motivated by recent results highlighting radically different evolutionary pathways between early- and late-type galaxies, ...

    • Galaxy Zoo: Hanny's Voorwerp, a quasar light echo? 

      Lintott, C.; Schawinski, K.; Keel, W.; Van Arkel, H.; Bennert, N.; Edmondson, E.; Thomas, D.; Smith, Daniel; Herbert, P.D.; Jarvis, M.J.; Virani, S.; Andreescu, D.; Bamford, S.; Land, K.; Murray, P.; Nichol, R.C.; Raddick, M.J.; Slosar, A.; Szalay, A.; Vandenberg, J. (2009)
      We report the discovery of an unusual object near the spiral galaxy IC 2497, discovered by visual inspection of the Sloan Digital Sky Survey (SDSS) as part of the Galaxy Zoo project. The object, known as Hanny's Voorwerp, ...

    • Galaxy Zoo: Multimergers and the Millennium Simulation 

      Darg, D.W.; Kaviraj, S.; Lintott, C.J.; Silk, J.; Lynn, S.; Schawinski, K.; Bamford, S.; Nichol, R.C. (2011-09)
      We present a catalogue of 39 multiple mergers, found using the mergers catalogue of the Galaxy Zoo project for z <0.1, and compare them to corresponding semi-analytical galaxies from the Millennium Simulation. We estimate ...

    • 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 ...