Publications by Ryan Houghton


Fast and slow rotators in the densest environments: a FLAMES/GIRAFFE IFS study of galaxies in Abell 1689 at z = 0.183 (vol 429, pg 1258, 2013)

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 447 (2015) 1398-1398

F D'Eugenio, RCW Houghton, RL Davies, E Dalla Bonta


The SAMI Pilot Survey: the kinematic morphology-density relation in Abell 85, Abell 168 and Abell 2399

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 443 (2014) 485-503

LMR Fogarty, N Scott, MS Owers, S Brough, SM Croom, MB Pracy, RCW Houghton, J Bland-Hawthorn, M Colless, RL Davies, DH Jones, JT Allen, JJ Bryant, M Goodwin, AW Green, IS Konstantopoulos, JS Lawrence, S Richards, L Cortese, R Sharp


Distribution of slow and fast rotators in the Fornax cluster

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 441 (2014) 274-288

N Scott, RL Davies, RCW Houghton, M Cappellari, AW Graham, KA Pimbblet


Integral field spectroscopy of high redshift galaxies with the HARMONI spectrograph on the European Extremely Large Telescope

GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY V 9147 (2014) ARTN 91478Z

S Kendrew, S Zieleniewski, N Thatte, J Devriendt, R Houghton, T Fusco, M Tecza, F Clarke, K O'Brien


Simulating observations with HARMONI: the integral field spectrograph for the European Extremely Large Telescope

GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY V 9147 (2014) ARTN 914793

S Zieleniewski, N Thatte, S Kendrew, R Houghton, M Tecza, F Clarke, T Fusco, M Swinbank


HARMONI: the first light integral field spectrograph for the E-ELT

GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY V 9147 (2014) ARTN 914725

NA Thatte, F Clarke, I Bryson, H Schnetler, M Tecza, RM Bacon, A Remillieux, E Mediavilla, JM Herreros Linares, S Arribas, CJ Evans, DW Lunney, T Fusco, K O'Brien, IA Tosh, DJ Ives, G Finger, R Houghton, RL Davies, JD Lynn, JR Allen, SD Zieleniewski, S Kendrew, V Ferraro-Wood, A Pecontal-Rousset, J Kosmalski, J Richard, A Jarno, AM Gallie, DM Montgomery, D Henry, G Zins, D Freeman, B Garcia-Lorenzo, L Fernando Rodriguez-Ramos, J Sanchez-Capuchino Revuelta, E Hernandez-Suarez, A Bueno-Bueno, JV Gigante-Ripoll, A Garcia, K Dohlen, B Neichel


Fast and slow rotators in the densest environments: A FLAMES/GIRAFFE integral field spectroscopy study of galaxies in a1689 at z = 0.183

Monthly Notices of the Royal Astronomical Society 429 (2013) 1258-1266

F D'Eugenio, RCW Houghton, RL Davies, E Dalla Bontà

We present FLAMES/GIRAFFE integral field spectroscopy of 30 galaxies in the massive cluster A1689 at z = 0.183. Conducting an analysis similar to that of ATLAS3D, we extend the baseline of the kinematic morphology-density relation by an order of magnitude in projected density and show that it is possible to use existing instruments to identify slow and fast rotators beyond the local Universe. We find 4.5 ± 1.0 slow rotators with a distribution in magnitude similar to those in the Virgo cluster. The overall slow rotator fraction of our A1689 sample is 0.15 ± 0.03, the same as in Virgo using our selection criteria. This suggests that the fraction of slow rotators in a cluster is not strongly dependent on its density. However, within A1689, we find that the fraction of slow rotators increases towards the centre, as was also found in the Virgo cluster. © 2012 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.


High resolution in three dimensions with SWIFT and PALM3K

3rd AO4ELT Conference - Adaptive Optics for Extremely Large Telescopes (2013)

F Clarke, N Thatte, M Tecza, K O'Brien, R Houghton, D Tice, L Fletcher, P Irwin, A Verma, R Dekany, R Buruss, J Roberts

SWIFT is a visible light (650-1000nm) integral field spectorgaph fed by the Palomar extreme adaptive optics system PALM3K. With a subaperture spacing of 8cm, PALM3K is capable of delivering diffraction limited performance even in the visible. With SWIFT providing spatially resolved spectroscopy at R=4000, this provides a truly unique facility for high resolution science in three dimensions. We present here some results from the first year of PALM3K+SWIFT science. We also report on our experience of operating a small field of view instrument (1"x0.5") with a high performance AO system, and hope the lessons learned will provide valuable input to designing successful and productive AO plus Instrument combinations for ELTs.


Angular Momentum of Galaxies in the Densest Environments: A FLAMES/GIRAFFE IFS Study of the Massive Cluster Abell 1689 at z = 0.18

The Messenger 151 (2013) 37-40

F D Eugenio, RCW Houghton, RL Davies, E Dalla Bontà


VizieR Online Data Catalog: Abell 1689 imaging and spectroscopy (Houghton+, 2012)

VizieR Online Data Catalog 742 (2013) 30256-30256

RCW Houghton, RL Davies, E Dalla Bonta, R Masters


Photometric analysis of Abell 1689

Proceedings of the International Astronomical Union Cambridge University Press (CUP) 8 (2012) 230-230

ED Bontà, RL Davies, RCW Houghton, F D'Eugenio, EM Corsini, J Méndez-Abreu

<jats:title>Abstract</jats:title><jats:p>We carried out a photometric analysis of a sample of early-type galaxies in Abell~1689 at <jats:italic>z</jats:italic> = 0.183, using <jats:italic>HST</jats:italic>/ACS archive images in the rest-frame <jats:italic>V</jats:italic> band. We performed a two-dimensional photometric decomposition of each galaxy surface-brightness distribution using the GASP2D fitting algorithm (Méndez-Abreu <jats:italic>et al</jats:italic>. 2008). We adopted both a Sérsic and de Vaucouleurs law. S0 galaxies were analysed also taking into account a disc component described by an exponential law. The derived photometric parameters, together with the ones previously obtained with the curve of growth method (Houghton <jats:italic>et al</jats:italic>. 2012), will be used to analyse the Fundamental Plane of Abell 1689 and quantify how it is affected by the use of different decomposition techniques (Dalla Bontà <jats:italic>et al</jats:italic>. 2013, in preparation). The stellar velocity dispersions of the sample galaxies were derived by using GEMINI-N/GMOS and VLT/FLAMES (D'Eugenio <jats:italic>et al</jats:italic>. 2013) spectroscopic data.</jats:p>


Improving the observing efficiency of SINFONI and KMOS at the VLT by factors of 2 to 4: sophisticated sky subtraction algorithms

OBSERVATORY OPERATIONS: STRATEGIES, PROCESSES, AND SYSTEMS IV 8448 (2012) ARTN 844809

NA Thatte, N Scott, R Houghton, D Nuernberger, RN Abuter, M Tecza


An oxford swift integral field spectroscopy study of 14 early-type galaxies in the coma cluster

Monthly Notices of the Royal Astronomical Society 425 (2012) 1521-1526

N Scott, R Houghton, RL Davies, M Cappellari, N Thatte, F Clarke, M Tecza

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 Sloan Digital Sky Survey archive for 14 early-type galaxies. We derive spatially resolved kinematics for all objects from observations of the calcium triplet absorption features at ∼8500Å. 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 ATLAS 3D survey, finding that the slow rotator fraction is ∼50per cent larger in the core of the Coma cluster than in the volume-limited ATLAS 3D sample, a 1.2σ 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 σ e with the photometric data we determine the Fundamental Plane for our sample of galaxies. We find that the use of the average velocity dispersion within 1 effective radius, σ e, reduces the residuals by 13per cent with respect to comparable studies using central velocity dispersions, consistent with other recent integral field Fundamental Plane determinations. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.


Data and two-dimensional scaling relations for galaxies in Abell 1689: a hint of size evolution at z similar to 0.2

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 423 (2012) 256-283

RCW Houghton, RL Davies, E Dalla Bonta, R Masters


The SAURON project - XVIII. The integrated UV-line-strength relations of early-type galaxies

Monthly Notices of the Royal Astronomical Society (2011)

M Bureau, H Jeong, SK Yi, K Schawinski, RCW Houghton, RL Davies, R Bacon, M Cappellari, PT de Zeeuw, E Emsellem, J Falcón-Barroso, D Krajnović, H Kuntschner, RM Mcdermid, RF Peletier, M Sarzi, Y-J Sohn, D Thomas, RCE van den Bosch, G van de Ven


Oxford SWIFT integral field spectrograph and multiwavelength observations of the Eagle galaxy at z= 0.77

Monthly Notices of the Royal Astronomical Society 417 (2011) 2882-2890

SA Kassin, L Fogarty, T Goodsall, FJ Clarke, RWC Houghton, G Salter, N Thatte, M Tecza, RL Davies, BJ Weiner, CNA Willmer, S Salim, MC Cooper, JA Newman, K Bundy, CJ Conselice, AM Koekemoer, L Lin, LA Moustakas, T Wang

The 'Eagle' galaxy at a redshift of 0.77 is studied with the Oxford Short Wavelength Integral Field Spectrograph (SWIFT) and multiwavelength data from the All-wavelength Extended Groth strip International Survey (AEGIS). It was chosen from AEGIS because of the bright and extended emission in its slit spectrum. 3D kinematic maps of the Eagle reveal a gradient in velocity dispersion which spans 35-75 ± 10kms-1 and a rotation velocity of 25 ± 5kms-1 uncorrected for inclination. Hubble Space Telescope images suggest it is close to face-on. In comparison with galaxies from AEGIS at similar redshifts, the Eagle is extremely bright and blue in the rest-frame optical, highly star forming, dominated by unobscured star formation and has a low metallicity for its size. This is consistent with its selection. The Eagle is likely undergoing a major merger and is caught in the early stage of a starburst when it has not yet experienced metal enrichment or formed the mass of dust typically found in star-forming galaxies. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS.


The SAURON project - XVIII. The integrated UV-line-strength relations of early-type galaxies

Monthly Notices of the Royal Astronomical Society 414 (2011) 1887-1902

M Bureau, H Jeong, SK Yi, K Schawinski, RCW Houghton, RL Davies, R Bacon, M Cappellari, PT de Zeeuw, E Emsellem, J Falcón-Barroso, D Krajnović, H Kuntschner, RM McDermid, RF Peletier, M Sarzi, YJ Sohn, D Thomas, RCE van den Bosch, G van de Ven

Using far-ultraviolet (FUV) and near-ultraviolet (NUV) photometry from guest investigator programmes on the Galaxy Evolution Explorer (GALEX) satellite, optical photometry from the MDM Observatory and optical integral-field spectroscopy from SAURON, we explore the UV-line-strength relations of the 48 nearby early-type galaxies in the SAURON sample. Identical apertures are used for all quantities, avoiding aperture mismatch. We show that galaxies with purely old stellar populations show well-defined correlations of the integrated FUV -V and FUV - NUV colours with the integrated Mg b and Hβ absorption line-strength indices, strongest for FUV - NUV. Correlations with the NUV -V colour, Fe5015 index and stellar velocity dispersion σ are much weaker. These correlations put stringent constraints on the origin of the UV-upturn phenomenon in early-type galaxies and highlight its dependence on age and metallicity. In particular, despite recent debate, we recover the negative correlation between FUV -V colour and Mg line strength originally publicized by Burstein et al., which we refer to as the 'Burstein relation', suggesting a positive dependence of the UV upturn on metallicity. We argue that the scatter in the correlations is real and present mild evidence that a strong UV excess is preferentially present in slow-rotating galaxies. We also demonstrate that most outliers in the correlations are galaxies with current or recent star formation, some at very low levels. We believe that this sensitivity to weak star formation, afforded by the deep and varied data available for the SAURON sample, explains why our results are occasionally at odds with other recent but shallower surveys. This is supported by the analysis of a large, carefully crafted sample of more distant early-type galaxies from the Sloan Digital Sky Survey (SDSS), more easily comparable with current and future large surveys. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS.


SWIFT observations of the Arp 147 ring galaxy system

Monthly Notices of the Royal Astronomical Society 417 (2011) 835-844

L Fogarty, N Thatte, M Tecza, F Clarke, T Goodsall, R Houghton, G Salter, RL Davies, SA Kassin

We present observations of Arp 147, a galaxy system comprising a collisionally created ring galaxy and an early-type galaxy, using the Oxford SWIFT integral field spectrograph (IFS) at the 200-inch Hale telescope. We derive spatially resolved kinematics from the IFS data and use these to study the interaction between the two galaxies. We find the edge-to-edge expansion velocity of the ring is 225 ± 8kms-1, implying an upper limit on the time-scale for the collision of 50Myr. We also calculate that the angle of impact for the collision is between, where 0° would imply a perpendicular collision. The ring galaxy is strongly star forming with the star formation likely to have been triggered by the collision between the two galaxies. We also measure some key physical parameters in an integrated and spatially resolved manner for the ring galaxy. Using the observed B-I colours and the Hα equivalent widths, we conclude that two stellar components (a young and an old population) are required everywhere in the ring to simultaneously match both observed quantities. We are able to constrain the age range, light and mass fractions of the young star formation activity in the ring, finding a modest age range, a light fraction of less than a third, and a negligible (<1 per cent) mass fraction. We postulate that the redder colours observed in the south-east corner of the ring galaxy could correspond to the nuclear bulge of the original disc galaxy from which the ring was created, consistent with the stellar mass in the south-east quadrant being 30-50 per cent of the total. The ring appears to have been a typical disc galaxy prior to the encounter. The ring shows electron densities consistent with typical values for star-forming Hii regions. The eastern half of the ring exhibits a metallicity a factor of ~2 higher than the western half. The ionization parameter, measured across the ring, roughly follows the previously observed trend with metallicity. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS.


An Integral Field View of Early-Type Galaxies in the Coma Cluster

American Astronomical Society Meeting Abstracts #217 43 (2011) #148.08-#148.08
Part of a series from Bulletin of the American Astronomical Society

N Scott, R Houghton, RL Davies, N Thatte, M Cappellari, F Clarke, L Fogarty, M Tecza


The Fundamental Plane of Abell 1689 compared to Coma

Fornax, Virgo, Coma et al., Stellar Systems in High Density Environments (2011) 20P-20P

R Houghton

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