Galaxies in southern bright star fields. I. Near-infrared imaging

Astronomy and Astrophysics 406:2 (2003) 593-601

Authors:

AJ Baker, RI Davies, MD Lehnert, NA Thatte, WD Vacca, OR Hainaut, MJ Jarvis, GK Miley, HJA Röttgering

Abstract:

As a prerequisite for cosmological studies using adaptive optics techniques, we have begun to identify and characterize faint sources in the vicinity of bright stars at high Galactic latitudes. The initial phase of this work has been a program of Ks imaging conducted with SOFI at the ESO NTT. From observations of 42 southern fields evenly divided between the spring and autumn skies, we have identified 391 additional stars and 1589 galaxies lying at separations Δθ ≤ 60″ from candidate guide stars in the magnitude range 9.0 ≤ R ≤ 12.4. When analyzed as a "discrete deep field" with 131 arcmin2 area, our dataset gives galaxy number counts that agree with those derived previously over the range 16 ≤ Ks < 20.5. This consistency indicates that in the aggregate, our fields should be suitable for future statistical studies. We provide our source catalogue as a resource for users of large telescopes in the southern hemisphere.

ISO photometry of hyperluminous infrared galaxies: Implications for the origin of their extreme luminosities

European Space Agency, (Special Publication) ESA SP (2003) 301-304

Authors:

A Verma, M Rowan-Robinson, R McMahon, A Efstathiou

Abstract:

We present 7-180μm photometry of a sample of hyperluminous infrared galaxies (HyLIGs) obtained with the photometer and camera mounted on the Infrared Space Observatory (ISO). We have used state-of-the-art' radiative transfer models of obscured starbursts and dusty tori to model their broadband spectral energy distributions (SEDs). We find that IRAS F00235+1024, IRAS F14218+3845 and IRAS F15307+3252 require a combination of starburst and AGN components to explain their mid to far-infrared emission, while for TXS0052+471 a dust torus model alone is sufficient. For IRAS F00235+1024 and IRAS F14218+3845 the starburst component is the predominant contributor whereas for IRAS F15307+3252 the dust torus component dominates. The implied star formation rates (SFR) estimated from the starburst infrared luminosities are dM*,all/dt > 1000M⊙yr-1h50-2 and are amongst the highest SFRs estimated to date. We also demonstrate that the well-known radio-FIR correlation observed for extragalactic sources extends into both higher radio and infrared power than previously investigated. The relation for HyLIGs has a mean q value of 1.94. The results of this study imply that better sampling of the IR SEDs of HyLIGs may reveal that both AGN and starburst components are required to explain their emission from the NIR to the sub-millimetre.

Radio galaxy host properties spanning three dex in radio luminosity

New Astronomy Reviews 47:4-5 (2003) 187-191

Authors:

CJ Willott, RJ McLure, MJ Jarvis, S Rawlings, GJ Hill, E Mitchell, JS Dunlop

Abstract:

We describe a major study of radio source host galaxies being carried out with the HST and ground-based facilities. Our sample is selected from 4 complete samples with different radio flux-density limits, giving a range of three orders of magnitude in radio luminosity at a fixed epoch (z=0.5). High-resolution HST WFPC2 imaging shows that all 44 radio galaxies have flux distributions well fit by an r1/4 law and lying on the Kormendy relation defined by lower redshift ellipticals with a shift in the zero-point to account for passive evolution. Spectroscopic follow-up enables stellar velocity dispersions to be determined and black hole masses estimated. The clustering environments of the radio galaxies are being probed via multi-colour wide-field imaging. Together, these data allow a detailed investigation of how factors such as clustering environment, close interactions and star-formation history affect the accretion rate, ionizing luminosity and jet production from supermassive black holes. © 2003 Elsevier B.V. All rights reserved.

The host galaxies of flat-spectrum quasars

New Astronomy Reviews 47:4-5 (2003) 183-186

Authors:

MJ Jarvis, RJ McLure

Abstract:

We present the results of deep VLT-ISAAC Ks-band imaging of four z∼1.5 flat-spectrum quasars selected from the Parkes half-Jansky flat spectrum sample. We find that the hosts of these flat-spectrum quasars are consistent with lying on the K-z Hubble relation for radio galaxies. This implies that the flat-spectrum quasar hosts fall in line with the expectations from orientation based unified schemes and also that they contain black holes of similar mass. Moreover, the width of the Hβ broad emission line in these objects tends to be narrower than in their misaligned (low-frequency selected quasar) counterparts, implying that the width of the Hβ broad emission line depends on source inclination, at least for radio-loud quasars, in line with previous studies. © 2003 Elsevier B.V. All rights reserved.

3D Spectroscopy of Z ∼ 1 Galaxies with Gemini

Chapter in The Evolution of Galaxies, Springer Nature (2003) 679-682

Authors:

Joanna Smith, Andrew Bunker, Richard Bower