Extremely Large Telescope

Abstract:

We present physical properties of two submillimeter selected gravitationally lensed sources, identified in the Herschel Astrophysical Terahertz Large Area Survey. These submillimeter galaxies (SMGs) have flux densities >100 mJy at 500 μm, but are not visible in existing optical imaging. We fit light profiles to each component of the lensing systems in Spitzer IRAC 3.6 and 4.5 μm data and successfully disentangle the foreground lens from the background source in each case, providing important constraints on the spectral energy distributions (SEDs) of the background SMG at rest-frame optical-near-infrared wavelengths. The SED fits show that these two SMGs have high dust obscuration with AV ∼ 4-5 and star formation rates of ∼ 100 M⊙ yr-1. They have low gas fractions and low dynamical masses compared with 850 μm selected galaxies. © 2011. The American Astronomical Society. All rights reserved. Printed in the U.S.A.

Abstract:

The Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) has uncovered a population of strongly lensed submillimeter galaxies (SMGs). The Zpectrometer instrument on the Green Bank Telescope (GBT) was used to measure the redshifts and constrain the masses of the cold molecular gas reservoirs for two candidate highredshift lensed sources. We derive CO(1-0) redshifts of z = 3.042 ± 0.001 and z = 2.625 ± 0.001, and measure molecular gas masses of (1-3) ×1010M⊙, corrected for lens amplification and assuming a conversion factor of α = 0.8 M ⊙ (Kkm s-1 pc2)-1. We find typical L(IR)/L'(CO) ratios of 120 ±40 and 140±50L ⊙ (Kkm s-1 pc2)-1, which are consistent with those found for local ultraluminous infrared galaxies (ULIRGs) and other high-redshift SMGs. From analysis of published data, we find no evidence for enhanced L(IR)/L'(CO(1-0)) ratios for the SMG population in comparison to local ULIRGs. The GBT results highlight the power of using the CO lines to derive blind redshifts, which is challenging for the SMGs at optical wavelengths given their high obscuration. © 2011. The American Astronomical Society. All rights reserved. Printed in the U.S.A.

Abstract:

We demonstrate experimentally that slicer based integral field spectrographs are an attractive choice for the next generation of exoplanet direct detection instruments. By propagating a single simulated speckle though a slicer based integral field spectrograph (IFS) and performing the post processing technique of spectral deconvolution we are able to achieve a speckle rejection factor of ∼600 in broadband images (and ∼100 in individual wavelength channels) with contrasts only appearing to be limited by calibration errors in the IFS datacube. This is over an order of magnitude improvement on the current state-of-the-art and well within the requirements of EPICS (Exo Planet Imaging Camera and Spectrograph for the E-ELT) for post coronagraphic speckle rejection thus proving that slicers will not impose a limit on the achievable contrast. When using prior knowledge of the diffraction-limited size of real objects we further improve the speckle rejection factor such that it exceeds 103.

Abstract:

We describe the current status of the HARMONI instrument design, which will form the basis for the first-light integral field spectrograph on the European Extremely Large Telescope. We review the phase A design, and highlight current on-going work to evolve the design in-line changing telescope requirements and lessons learned during the Phase A work. We also outline the key science drivers for the instrument, and describe briefly the requirements for the laser tomographic adaptive optics system which is expected to feed HARMONI.