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An Oxford SWIFT Integral Field Spectroscopy study of 14 early-type galaxies in the Coma cluster

ArXiv 1205.4299 (2012)

Authors:

Nicholas Scott, Ryan CW Houghton, Roger L Davies, Michele Cappellari, Niranjan Thatte, Fraser J Clarke, Matthias Tecza

Abstract:

As a demonstration of the capabilities of the new Oxford SWIFT integral field spectrograph, we present first observations for a set of 14 early-type galaxies in the core of the Coma cluster. Our data consist of I- and z-band spatially resolved spectroscopy obtained with the Oxford SWIFT spectrograph, combined with r-band photometry from the SDSS archive for 14 early- type galaxies. We derive spatially resolved kinematics for all objects from observations of the calcium triplet absorption features at \sim 8500 {AA} . Using this kinematic information we classify galaxies as either Fast Rotators or Slow Rotators. We compare the fraction of fast and slow rotators in our sample, representing the densest environment in the nearby Universe, to results from the ATLAS3D survey, finding the slow rotator fraction is \sim 50 per cent larger in the core of the Coma cluster than in the Virgo cluster or field, a 1.2 {\sigma} increase given our selection criteria. Comparing our sample to the Virgo cluster core only (which is 24 times less dense than the Coma core) we find no evidence of an increase in the slow rotator fraction. Combining measurements of the effective velocity dispersion {\sigma_e} with the photometric data we determine the Fundamental Plane for our sample of galaxies. We find the use of the average velocity dispersion within 1 effective radius, {\sigma_e}, reduces the residuals by 13 per cent with respect to comparable studies using central velocity dispersions, consistent with other recent integral field Fundamental Plane determinations.
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Constraining stellar assembly and AGN feedback at the peak epoch of star formation

ArXiv 1205.3801 (2012)

Authors:

Taysun Kimm, Sugata Kaviraj, Julien Devriendt, Seth Cohen, Rogier Windhorst, Yohan Dubois, Adrianne Slyz, Nimish Hathi, Russell Ryan Jr, Robert O'Connell, Michael Dopita, Joseph Silk

Abstract:

We study stellar assembly and feedback from active galactic nuclei (AGN) around the epoch of peak star formation (1
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Constraining stellar assembly and AGN feedback at the peak epoch of star formation

(2012)

Authors:

Taysun Kimm, Sugata Kaviraj, Julien Devriendt, Seth Cohen, Rogier Windhorst, Yohan Dubois, Adrianne Slyz, Nimish Hathi, Russell Ryan, Robert O'Connell, Michael Dopita, Joseph Silk
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X-ray signatures of circumnuclear gas in AGN

AIP Conference Proceedings 1427 (2012) 165-172

Authors:

TJ Turner, L Miller, M Tatum

Abstract:

X-ray spectra of AGN are complex. X-ray absorption and emission features trace gas covering a wide range of column densities and ionization states. High resolution spectra show the absorbing gas to be outflowing, perhaps in the form of an accretion disk wind. The absorbing complex shapes the form of the X-ray spectrum while X-ray reverberation and absorption changes explain the spectral and timing behaviour of AGN. We discuss recent progress, highlighting some new results and reviewing the implications that can be drawn from the data. © 2012 American Institute of Physics.
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The likelihood ratio as a tool for radio continuum surveys with Square Kilometre Array precursor telescopes†

Monthly Notices of the Royal Astronomical Society (2012)

Authors:

K Mcalpine, DJB Smith, MJ Jarvis, DG Bonfield, S Fleuren

Abstract:

In this paper we investigate the performance of the likelihood ratio method as a tool for identifying optical and infrared counterparts to proposed radio continuum surveys with Square Kilometre Array (SKA) precursor and pathfinder telescopes. We present a comparison of the infrared counterparts identified by the likelihood ratio in the VISTA Deep Extragalactic Observations (VIDEO) survey to radio observations with 6, 10 and 15arcsec resolution. We cross-match a deep radio catalogue consisting of radio sources with peak flux density > 60 Jy with deep near-infrared data limited to K s ≲ 22.6. Comparing the infrared counterparts from this procedure to those obtained when cross-matching a set of simulated lower resolution radio catalogues indicates that degrading the resolution from 6arcsec to 10 and 15arcsec decreases the completeness of the cross-matched catalogue by approximately 3 and 7per cent respectively. When matching against shallower infrared data, comparable to that achieved by the VISTA Hemisphere Survey, the fraction of radio sources with reliably identified counterparts drops from ∼89 per cent, at K s ≲ 22.6, to 47 per cent with K s ≲ 20.0. Decreasing the resolution at this shallower infrared limit does not result in any further decrease in the completeness produced by the likelihood ratio matching procedure. However, we note that radio continuum surveys with the MeerKAT and eventually the SKA, will require long baselines in order to ensure that the resulting maps are not limited by instrumental confusion noise. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.
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