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Browsing by Author "Kaviraj, S."
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Active galactic nucleus feedback drives the colour evolution of local galaxies
Shabala, S.S.; Kaviraj, S.; Silk, J. (2011-06-01)We investigate the effects of active galactic nucleus (AGN) feedback on the colour evolution of galaxies found in local (z <0.2) groups and clusters. Galaxies located within the lobes of powerful Fanaroff-Riley type II ... -
AGN jet-induced feedback in galaxies - II : Galaxy colours from a multicloud simulation
Tortora, C.; Antonuccio-Delogu, V.; Romeo, A.D.; Becciani, U.; Kaviraj, S.; Silk, J. (2009-06-01)We study the feedback from an active galactic nucleus (AGN) on stellar formation within its host galaxy, mainly using one high-resolution numerical simulation of the jet propagation within the interstellar medium (ISM) of ... -
ALMA observations of massive molecular gas reservoirs in dusty early-type galaxies
Sansom, A. E.; Glass, D. H. W.; Bendo, G. J.; Davis, T. A.; Rowlands, K.; Bourne, N.; Dunne, L.; Eales, S.; Kaviraj, S.; Popescu, C.; Smith, M.; Viaene, S. (2019-02-01)Unresolved gas and dust observations show a surprising diversity in the amount of interstellar matter in early-type galaxies. Using Atacama Large Millimetre/submillimeter Array (ALMA) observations we resolve the ISM in z ... -
Anatomy of a post-starburst minor merger : A multi-wavelength WFC3 study of NGC 4150
Crockett, R.M.; Kaviraj, S.; Silk, J.I.; Whitmore, B.C.; Mutchler, M.; Bond, H.E.; O'Connell, R.W.; Balick, B.; Calzetti, D.; Carollo, C.M.; Disney, M.J.; Dopita, M.A.; Frogel, J.A.; Hall, D.N.B.; Holtzman, J. A.; Kimble, R.A.; McCarthy, P.J.; Paresce, F.; Saha, A.; Trauger, J.T.; Walker, A.R.; Windhorst, R.A.; Young, E.T.; Jeong, H.; Yi, S.K. (2011-02-01)We present a spatially resolved near-UV/optical study, using the Wide Field Camera 3 (WFC3) on board the Hubble Space Telescope, of NGC 4150, a sub-L , early-type galaxy (ETG) of around 6 × 10 M , which has been observed ... -
Better age estimation using ultraviolet-optical colours : Breaking the age-metallicity degeneracy
Kaviraj, S.; Rey, S.-C.; Yoon, S.-J.; Yi, S.K.; Rich, R.M. (2007-10-01)We demonstrate that the combination of GALEX ultraviolet (UV) photometry in the far-UV (FUV; ~1530 Å) and near-UV (NUV; ~2310 Å) passbands with optical photometry in the standard U, B, V, R, I filters can efficiently break ... -
A catalogue of faint local radio AGN and the properties of their host galaxies
Lofthouse, E. K.; Kaviraj, S.; Smith, D. J. B.; Hardcastle, M. J. (2018-09-01)We present a catalogue of 2210 local ( z < 0.1) galaxies that contain faint active galactic nuclei (AGN). We select these objects by identifying galaxies that exhibit a significant excess in their radio luminosities, ... -
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 ... -
Chronos: A NIR spectroscopic galaxy survey to probe the most fundamental stages of galaxy evolution
Ferreras, I.; Cropper, M.; Sharples, R.; Bland-Hawthorn, J.; Bruzual, G.; Charlot, S.; Conselice, C. J.; Driver, S.; Dunlop, J.; Hopkins, A. M.; Kaviraj, S.; Kitching, T.; Barbera, F. La; Lahav, O.; Pasquali, A.; Serjeant, S.; Silk, J.; Windhorst, R. (2021-07-18)We propose a dedicated, ultra-deep spectroscopic survey in the near infrared (NIR), that will target a mass-limited sample of galaxies during two of the most fundamental epochs of cosmic evolution: the formation of the ... -
A coincidence of disturbed morphology and blue UV colour : Minor-merger-driven star formation in early-type galaxies at z~ 0.6
Kaviraj, S.; Tan, K.-M.; Ellis, R.S.; Silk, J. (2011-03-01)We exploit multiwavelength photometry of early-type galaxies (ETGs) in the Cosmological Evolution Survey (COSMOS) to demonstrate that the low-level star formation activity in the ETG population at intermediate redshift is ... -
Composite star formation histories of early-type galaxies from minor mergers : prospects for WFC3
Peirani, S.; Crockett, R.M.; Geen, S.; Kaviraj, S.; Silk, J.; Khochfar, S. (2010-07-01)The star formation history of nearby early-type galaxies is investigated via numerical modelling. Idealized hydrodynamical N-body simulations with a star formation prescription are used to study the minor merger process ... -
Constraining stellar assembly and active galactic nucleus feedback at the peak epoch of star formation
Kimm, T.; Kaviraj, S.; Devriendt, J.E.G.; Dubois, Y.; Slyz, A.; Cohen, S.H.; Windhorst, R.A.; Silk, J.; Hathi, N.P.; Ryan, R.E.; O'Connell, R.W.; Dopita, M.A. (2012-09-01)We study stellar assembly and feedback from active galactic nuclei (AGN) around the epoch of peak star formation (1 ≲ z ≲ 2), by comparing hydrodynamic simulations to rest-frame UV-optical galaxy colours from the Wide Field ... -
Cosmic evolution of stellar quenching by AGN feedback : clues from the Horizon-AGN simulation
Beckmann, R. S.; Devriendt, J.E.G.; Slyz, A.; Peirani, S.; Richardson, M. L. A.; Dubois, Y.; Pichon, C.; Chisari, N. E.; Kaviraj, S.; Laigle, C.; Volonteri, M. (2017-11-21)The observed massive end of the galaxy stellar mass function is steeper than its predicted dark matter halo counterpart in the standard $\Lambda $CDM paradigm. In this paper, we investigate the impact of active galactic ... -
Dark-matter-deficient dwarf galaxies form via tidal stripping of dark matter in interactions with massive companions
Jackson, R. A.; Kaviraj, S.; Martin, G.; Devriendt, J. E. G.; Slyz, A.; Silk, J.; Dubois, Y.; Yi, S. K.; Pichon, C.; Volonteri, M.; Choi, H.; Kimm, T.; Kraljic, K.; Peirani, S. (2021-01-15)In the standard Lambda-CDM paradigm, dwarf galaxies are expected to be dark-matter-rich, as baryonic feedback is thought to quickly drive gas out of their shallow potential wells and quench star formation at early epochs. ... -
Decoding the spectra of SDSS early-type galaxies : New indicators of age and recent star formation
Rogers, B.; Ferreras, I.; Lahav, O.; Bernardi, M.; Kaviraj, S.; Yi, S.K. (2007-12-01)We apply principal component analysis (PCA) to a sample of early-type galaxies from the Sloan Digital Sky Survey (SDSS) in order to infer differences in their star formation histories from their unresolved stellar populations. ... -
Density profile of dark matter haloes and galaxies in the Horizon-AGN simulation : the impact of AGN feedback
Peirani, S.; Dubois, Y.; Volonteri, M.; Devriendt, J.E.G.; Bundy, K.; Silk, J.; Pichon, C.; Kaviraj, S.; Gavazzi, R.; Habouzit, M. (2017-12-01)Using a suite of three large cosmological hydrodynamical simulations, Horizon-AGN, Horizon-noAGN (no AGN feedback) and Horizon-DM (no baryons), we investigate how a typical sub-grid model for AGN feedback affects the ... -
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 ... -
The distribution of local star formation activity as a function of galaxy stellar mass, environment and morphology
Lofthouse, E. K.; Kaviraj, S.; Smith, D. J. B.; Hardcastle, M. J. (2017-12-21)We present a detailed inventory of star formation in the local Universe, dissecting the cosmic star formation budget as a function of key variables that influence the star formation rate (SFR) of galaxies: stellar mass, ... -
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 ... -
Early-type galaxies at intermediate redshift observed with hubble space telescope WFC3 : Perspectives on recent star formation
Rutkowski, Michael J.; Jeong, Hyunjin; Cohen, Seth H.; Kaviraj, S.; Windhorst, Rogier A.; Ryan, Russell E.; Koekemoer, Anton; Yi, Sukyoung K.; Hathi, Nimish P.; Dopita, Michael A. (2014-12-01)We present an analysis of the stellar populations of 102 visually selected early-type galaxies (ETGs) with spectroscopic redshifts (0.35 ≲ z ≲ 1.5) from observations in the Early Release Science program with the Wide Field ... -
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 ...