scholarly journals High-resolution survey for planetary companions to young stars in the Taurus molecular cloud

2020 ◽  
Vol 498 (1) ◽  
pp. 1382-1396
Author(s):  
A L Wallace ◽  
J Kammerer ◽  
M J Ireland ◽  
C Federrath ◽  
A L Kraus ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Near Infrared ◽  
Semimajor Axis ◽  
Infrared Camera ◽  
Single Class ◽  
Hot Start ◽  
Guide Star ◽  
Laser Guide ◽  
Large Telescopes ◽  
Differential Imaging

ABSTRACT Direct imaging in the infrared at the diffraction limit of large telescopes is a unique probe of the properties of young planetary systems. We survey 55 single class I and class II stars in Taurus in the L’ filter using natural and laser guide star adaptive optics and the near-infrared camera (NIRC2) of the Keck II telescope, in order to search for planetary-mass companions. We use both reference star differential imaging and kernel phase techniques, achieving typical 5σ contrasts of ∼6 mag at separations of 0.2 arcsec and ∼8 mag beyond 0.5 arcsec. Although, we do not detect any new faint companions, we constrain the frequency of wide separation massive planets, such as HR 8799 analogues. We find that, assuming hot-start models and a planet distribution with power-law mass and semimajor axis indices of −0.5 and −1, respectively, less than 20 per cent of our target stars host planets with masses >2 MJ at separations >10 au.

scholarly journals Extremely Large Telescopes on the Antarctic plateau

2005 ◽  
Vol 13 ◽  
pp. 956-957
Author(s):  
J.S. Lawrence
Keyword(s):  
Adaptive Optics ◽  
Turbulence Structure ◽  
Large Telescope ◽  
Dome A ◽  
Antarctic Plateau ◽  
Guide Star ◽  
Laser Guide ◽  
Large Telescopes ◽  
The Antarctic ◽  
Adaptive Optics System

AbstractThe primary limitation to the performance of any large ground-based telescope is the atmospheric properties of its site, particularly the sky emission and the turbulence structure. There are several sites on the Antarctic plateau (South Pole, Dome C and Dome A) for which the increase in infrared sensitivity relative to a mid-latitude site should be as much as two orders of magnitude. The unique turbulent structure above Dome C indicates that an extremely large telescope equipped with only a natural guide star adaptive optics system should achieve equivalent resolution to a mid-latitude extremely large telescope with a multi-conjugate multi-laser guide star system.

scholarly journals Wave-front error breakdown in laser guide star multi-object adaptive optics validated on-sky by Canary

2017 ◽  
Vol 598 ◽  
pp. A37 ◽  
Author(s):  
O. A. Martin ◽  
É. Gendron ◽  
G. Rousset ◽  
D. Gratadour ◽  
F. Vidal ◽  
...  
Keyword(s):  
Wave Front ◽  
Adaptive Optics ◽  
Open Loop ◽  
System Modelling ◽  
Large Set ◽  
Vertical Error ◽  
Guide Star ◽  
Laser Guide ◽  
Large Telescopes ◽  
William Herschel

Context. Canary is the multi-object adaptive optics (MOAO) on-sky pathfinder developed in the perspective of multi-object spectrograph on extremely large telescopes (ELTs). In 2013, Canary was operated on-sky at the William Herschel telescope (WHT), using three off-axis natural guide stars (NGS) and four off-axis Rayleigh laser guide stars (LGS), in open-loop, with the on-axis compensated turbulence observed with a H-band imaging camera and a Truth wave-front sensor (TS) for diagnostic purposes. Aims. Our purpose is to establish a reliable and accurate wave-front error breakdown for LGS MOAO. This will enable a comprehensive analysis of Canary on-sky results and provide tools for validating simulations of MOAO systems for ELTs. Methods. To evaluate the MOAO performance, we compared the Canary on-sky results running in MOAO, in single conjugated adaptive optics (SCAO) and in ground layer adaptive optics (GLAO) modes, over a large set of data acquired in 2013. We provide a statistical study of the seeing. We also evaluated the wave-front error breakdown from both analytic computations, one based on a MOAO system modelling and the other on the measurements from the Canary TS. We have focussed especially on the tomographic error and we detail its vertical error decomposition. Results. We show that Canary obtained 30.1%, 21.4% and 17.1% H-band Strehl ratios in SCAO, MOAO and GLAO respectively, for median seeing conditions with 0.66′′ of total seeing including 0.59′′ at the ground. Moreover, we get 99% of correlation over 4500 samples, for any AO modes, between two analytic computations of residual phase variance. Based on these variances, we obtain a reasonable Strehl-ratio (SR) estimation when compared to the measured IR image SR. We evaluate the gain in compensation for the altitude turbulence brought by MOAO when compared to GLAO.

scholarly journals Commission 9: Instruments and techniques

1997 ◽  
Vol 23 (1) ◽  
pp. 498-514 ◽  
Keyword(s):  
Adaptive Optics ◽  
High Angular Resolution ◽  
Large Format ◽  
Atmospheric Compensation ◽  
Near Ir ◽  
Instruments And Techniques ◽  
Guide Star ◽  
Laser Guide ◽  
Optic Systems ◽  
Large Telescopes

During the period covered by this report, major progresses have been achieved in various fields of astronomical techniques and instruments. The era of large telescopes has been opened with the commissioning of the 2 Keck telescopes and the final construction phase for major facilities (ESO, JNLT, LBT, Gemini, etc). More than ten telescopes, with aperture larger than 8m, will be ready to scrutinize the sky, at the beginning of the next century. A Spanish project (GRANTBCAN) remains incompletely financed at this time. The power of these telescopes will be maximum when full diffraction limit capabilities will be available at their focus. The period 1994-1997 has seen major and spectacular achievements with realisation of several operationnal adaptative optic systems on 4m-class telescopes (ESO, CFHT). Diffraction limits have been reached at near-IR wavelength and partial correction, even in the visible, are bringing resolution comparable to space observations. All 8-10m projects require adaptative optics and have plans for it. In the meantime, 3-4m class telescopes are beeing equiped as well, so that AO will appear everywhere within the next 3 years. The necessary complement of adaptive optics, ie: the laser guide star, is thoroughly studied in order to provide full coverage for atmospheric compensation all over the sky. Projects of monochromatic and polychromatic laser stars are flourishing in relation with all telescopes with aperture of 3m-plus adaptative optics projects. Field coverage and achievable resolution require good pixel sampling and therefore large format detectors. Projects of very large format cameras for the visible and infrared are considered, up to 16kxl6k (MEGACAM at CFHT for 1.5 degrees field). Progress has been obtained in the industry to reduce gaps in between bootable CCDs, to reduce amplifiers noise and improve sensitivity. High angular resolution capabilities will gain another magnitude when the actual developments on interferometry with small telescopes will be tranfered to arrays of large telescopes (ESO, Keck, etc). Resolutions of 0.001 arc. sec will be available within 5 years leading to a gain of a factor 1000 compared to a 3.5m telescope operating today without adaptive optics.

scholarly journals A near-infrared tip-tilt sensor for the Keck I laser guide star adaptive optics system

2014 ◽  
Author(s):  
Peter Wizinowich ◽  
Roger Smith ◽  
Roberto Biasi ◽  
Sylvain Cetre ◽  
Richard Dekany ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Near Infrared ◽  
Laser Guide Star ◽  
Tilt Sensor ◽  
Guide Star ◽  
Laser Guide ◽  
Adaptive Optics System

scholarly journals First results from Project SUNBIRD: Supernovae UNmasked By Infra-Red Detection

2016 ◽  
Vol 12 (S329) ◽  
pp. 416-416
Author(s):  
Erik C. Kool ◽  
Stuart D. Ryder ◽  
Erkki Kankare ◽  
Seppo Mattila
Keyword(s):  
Adaptive Optics ◽  
Near Infrared ◽  
Infrared Galaxies ◽  
Dust Extinction ◽  
Luminous Infrared Galaxies ◽  
First Results ◽  
Nuclear Regions ◽  
Guide Star ◽  
Laser Guide ◽  
Optical Surveys

AbstractA substantial number of core-collapse supernovae (CCSNe) are expected to be hosted by starbursting luminous infrared galaxies (LIRGs). However, so far very few CCSNe have been discovered in LIRGs, most likely as a result of dust extinction and lack of contrast in their typically luminous and complex nuclear regions. We present the first results of Project SUNBIRD (Supernovae UNmasked By InfraRed Detection), where we aim to uncover dust-obscured nuclear supernovae by monitoring over 30 LIRGs, using near-infrared state-of-the-art Laser Guide Star Adaptive Optics (LGSAO) imaging on the Gemini South and Keck telescopes. Such discoveries are vital for determining the fraction of supernovae which will be missed as a result of dust obscuration by current and future optical surveys.

Laser guide star wavefront sensing for ground-layer adaptive optics on extremely large telescopes

2011 ◽  
Vol 50 (4) ◽  
pp. 473 ◽  
Author(s):  
Richard M. Clare ◽  
Miska Le Louarn ◽  
Clementine Béchet
Keyword(s):  
Adaptive Optics ◽  
Ground Layer ◽  
Wavefront Sensing ◽  
Laser Guide Star ◽  
Guide Star ◽  
Laser Guide ◽  
Large Telescopes
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