Black hole mass and eddington ratio distribution functions of X-ray-selected broad-line AGNs at z ∼ 1.4 in the Subaru XMM-Newton Deep Field
Astrophysical Journal 761:2 (2012)
Abstract:
In order to investigate the growth of supermassive black holes (SMBHs), we construct the black hole mass function (BHMF) and Eddington ratio distribution function (ERDF) of X-ray-selected broad-line active galactic nuclei (AGNs) at z ∼ 1.4 in the Subaru XMM-Newton Deep Survey (SXDS) field. A significant part of the accretion growth of SMBHs is thought to take place in this redshift range. Black hole masses of X-ray-selected broad-line AGNs are estimated using the width of the broad Mg II line and 3000 Å monochromatic luminosity. We supplement the Mg II FWHM values with the Hα FWHM obtained from our NIR spectroscopic survey. Using the black hole masses of broad-line AGNs at redshifts between 1.18 and 1.68, the binned broad-line AGN BHMFs and ERDFs are calculated using the V maxmethod. To properly account for selection effects that impact the binned estimates, we derive the corrected broad-line AGN BHMFs and ERDFs by applying the maximum likelihood method, assuming that the ERDF is constant regardless of the black hole mass. We do not correct for the non-negligible uncertainties in virial BH mass estimates. If we compare the corrected broad-line AGN BHMF with that in the local universe, then the corrected BHMF at z = 1.4 has a higher number density above 108 M⊙but a lower number density below that mass range. The evolution may be indicative of a downsizing trend of accretion activity among the SMBH population. The evolution of broad-line AGN ERDFs from z = 1.4 to 0 indicates that the fraction of broad-line AGNs with accretion rates close to the Eddington limit is higher at higher redshifts. © 2012. The American Astronomical Society. All rights reserved..15x optical zoom and extreme optical image stabilisation: Diffraction limited integral field spectroscopy with the SWIFT spectrograph
Proceedings of SPIE - The International Society for Optical Engineering 8446 (2012)
Abstract:
When commissioned in November 2008 at the Palomar 200 inch Hale Telescope, the Oxford SWIFT I&z band integral field spectrograph, fed by the adaptive optics system PALAO, provided a wide (3x) range of spatial resolutions: three plate scales of 235 mas, 160 mas, and 80 mas per spaxel over a contiguous field-of-view of 89x44 pixels. Depending on observing conditions and guide star brightness we can choose a seeing limited scale of 235 mas per spaxel, or 160 mas and 80 mas per spaxel for very bright guide star AO with substantial increase of enclosed energy. Over the last two years PALAO was upgraded to PALM-3000: an extreme, high-order adaptive optics system with two deformable mirrors with more than 3000 actuators, promising diffraction limited performance in SWIFT's wavelength range. In order to take advantage of this increased spatial resolution we upgraded SWIFT with new pre-optics allowing us to spatially Nyquist sample the diffraction limited PALM-3000 point spread function with 16 mas resolution, reducing the spaxel scale by another factor of 5x. We designed, manufactured, integrated and tested the new pre-optics in the first half of 2011 and commissioned it in December 2011. Here we present the opto-mechanical design and assembly of the new scale changing optics, as well as laboratory and on-sky commissioning results. In optimal observing conditions we achieve substantial Strehl ratios, delivering the near diffraction limited spatial resolution in the I&z bands. © 2012 SPIE.Engineering technology development in the UK for HARMONI: An E-ELT first light instrument
Proceedings of SPIE - The International Society for Optical Engineering 8450 (2012)
Abstract:
HARMONI is an integral field spectrograph working at visible and near-infrared wavelengths, over a range of spatial scales from ground layer corrected to fully diffraction-limited. The instrument has been chosen to be part of the first-light complement at the European Extremely Large Telescope (E-ELT1). This paper describes the engineering technology development being undertaken at the UKATC and Oxford to support E-ELT HARMONI2 instrument in its pre-phase-B stage. This includes the description of technology demonstrators for a tracking optical de-rotator to be located within the instrument vacuum vessel, a cryogenic shutter and a compact thermally compensating lens mount system. In addition the material testing facilities available at the UKATC are described which will enable the measurement of material and bolted joint thermal conductivities to 4K and friction/wear properties of material combinations to 20K. This work is undertaken to improve the instrument performance and reduce technical, cost and schedule risk. © 2012 SPIE.Multiplexing 32,000 spectra onto 8 detectors: The HARMONI field splitting, image slicing and wavelength selecting optics
Proceedings of SPIE - The International Society for Optical Engineering 8450 (2012)
Abstract:
HARMONI, the High Angular Resolution Monolithic Optical & Near-infrared Integral field spectrograph is one of two first-light instruments for the European Extremely Large Telescope. Over a 256x128 pixel field-of-view HARMONI will simultaneously measure approximately 32,000 spectra. Each spectrum is about 4000 spectral pixels long, and covers a selectable part of the 0.47-2.45 μm wavelength range at resolving powers of either R=4000, 10000, or 20000. All 32,000 spectra are imaged onto eight HAWAII4RG detectors using a multiplexing scheme that divides the input field into four sub-fields, each imaged onto one image slicer that in turn re-arranges a single sub-field into two long exit slits feeding one spectrograph each. In total we require eight spectrographs, each with one HAWAII4RG detector. A system of articulated and exchangeable fold-mirrors and VPH gratings allows one to select different spectral resolving powers and wavelength ranges of interest while keeping a fixed geometry between the spectrograph collimator and camera avoiding the need for an articulated grating and camera. In this paper we describe both the field splitting and image slicing optics as well as the optics that will be used to select both spectral resolving power and wavelength range. © 2012 SPIE.The opto-mechanical design of HARMONI: A first light integral field spectrograph for the E-ELT
Proceedings of SPIE - The International Society for Optical Engineering 8446 (2012)