Near-infrared spectrograph for a large telescope

Since the year 2000, adaptive optics (AO) has seen the emergence of a variety of new concepts addressing particular science needs; multiconjugate adaptive optics (MCAO) is one of them. By correcting the atmospheric turbulence in 3D using several wavefront sensors and a tomographic phase reconstruction approach, MCAO aims to provide uniform diffraction limited images in the near-infrared over fields of view larger than 1 arcmin2, i.e., 10 to 20 times larger in area than classical single conjugated AO. In this review, we give a brief reminder of the AO principles and limitations, and then focus on aspects particular to MCAO, such as tomography and specific MCAO error sources. We present examples and results from past or current systems: MAD (Multiconjugate Adaptive Optics Demonstrator) and GeMS (Gemini MCAO System) for nighttime astronomy and the AO system, at Big Bear for solar astronomy. We examine MCAO performance (Strehl ratio up to 40% in H band and full width at half maximum down to 52 mas in the case of MCAO), with a particular focus on photometric and astrometric accuracy, and conclude with considerations on the future of MCAO in the Extremely Large Telescope and post–HST era.

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Unidentified emission features in the R Coronae Borealis star V854 Centauri

Astronomy and Astrophysics ◽

10.1051/0004-6361/201731549 ◽

2018 ◽

Vol 610 ◽

pp. L6 ◽

Cited By ~ 2

Author(s):

L. C. Oostrum ◽

B. B. Ochsendorf ◽

L. Kaper ◽

A. G. G. M. Tielens

Keyword(s):

Near Infrared ◽

Physical Nature ◽

The Other ◽

Large Telescope ◽

Circumstellar Material ◽

Spatially Resolved ◽

Broad Emission ◽

Very Large Telescope ◽

New Feature ◽

Molecular Nature

During its 2012 decline, the R Coronae Borealis star (RCB) V854 Cen was spectroscopically monitored with X-shooter on the ESO Very Large Telescope. The obscured optical and near-infrared spectrum exhibits many narrow and several broad emission features, as previously observed. The envelope is spatially resolved along the slit and allows for a detailed study of the circumstellar material. In this Letter, we report on the properties of a number of unidentified visual emission features (UFs), including the detection of a new feature at 8692 Å. These UFs have been observed in the Red Rectangle (RR), but their chemical and physical nature is still a mystery. The previously known UFs behave similarly in the RR and in V854 Cen, but are not detected in six other observed RCBs. Some hydrogen might be required for the formation of their carrier(s). The λ8692 UF is present in all RCBs. Its carrier is likely of a carbonaceous molecular nature, presumably different from that of the other UFs.

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The dwarf planet Makemake as seen by X-Shooter

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2329 ◽

2020 ◽

Vol 497 (4) ◽

pp. 5473-5479

Author(s):

Alvaro Alvarez-Candal ◽

Ana Carolina Souza-Feliciano ◽

Walter Martins-Filho ◽

Noemí Pinilla-Alonso ◽

José Luis Ortiz

Keyword(s):

Infrared Spectrum ◽

Near Infrared ◽

Resolving Power ◽

Large Telescope ◽

Very Large Telescope ◽

Absorption Features ◽

Near Infrared Spectrum

ABSTRACT Makemake is one of the brightest known trans-Neptunian objects, as such, it has been widely observed. Nevertheless, its visibility to near-infrared spectrum has not been completely observed in medium-resolving power, aimed at studying in detail the absorption features of CH4 ice. In this paper, we present the spectrum of Makemake observed with X-Shooter at the Very Large Telescope (Chile). We analyse the detected features, measuring their location and depth. Furthermore, we compare Makemake’s spectrum with that of Eris, obtained with the same instrument and similar setup, to conclude that the bands of the CH4 ice in both objects show similar shifts.

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A Near Infrared Integral Field spectrograph (NIR) for the Southern African Large Telescope (SALT): mechanical design

Ground-based and Airborne Instrumentation for Astronomy VII ◽

10.1117/12.2313906 ◽

2018 ◽

Author(s):

Michael P. Smith ◽

Douglas P. Adler ◽

Matthew A. Bershady ◽

Kurt P. Jaehnig ◽

Ron J. Koch ◽

...

Keyword(s):

Near Infrared ◽

Mechanical Design ◽

Large Telescope ◽

Integral Field Spectrograph ◽

Integral Field

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PROSPECTS FOR TESTING THE NATURE OF Sgr A*'s NEAR-INFRARED FLARES ON THE BASIS OF CURRENT VERY LARGE TELESCOPE—AND FUTURE VERY LARGE TELESCOPE INTERFEROMETER—OBSERVATIONS

The Astrophysical Journal ◽

10.1088/0004-637x/692/1/902 ◽

2009 ◽

Vol 692 (1) ◽

pp. 902-916 ◽

Cited By ~ 45

Author(s):

N. Hamaus ◽

T. Paumard ◽

T. Müller ◽

S. Gillessen ◽

F. Eisenhauer ◽

...

Keyword(s):

Near Infrared ◽

Large Telescope ◽

Very Large Telescope ◽

Sgr A

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Polarimetry of relativistic tidal disruption event Swift J2058+0516

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz3106 ◽

2019 ◽

Vol 491 (2) ◽

pp. 1771-1776 ◽

Cited By ~ 2

Author(s):

K Wiersema ◽

A B Higgins ◽

A J Levan ◽

R A J Eyles ◽

R L C Starling ◽

...

Keyword(s):

Linear Polarization ◽

Near Infrared ◽

Thermal Emission ◽

Large Telescope ◽

Relativistic Jets ◽

Tidal Disruption ◽

Very Large Telescope ◽

Wide Range ◽

Independent Test ◽

Show Evidence

ABSTRACT A small fraction of candidate tidal disruption events (TDEs) show evidence of powerful relativistic jets, which are particularly pronounced at radio wavelengths, and likely contribute non-thermal emission at a wide range of wavelengths. A non-thermal emission component can be diagnosed using linear polarimetry, even when the total received light is dominated by emission from an accretion disc or disc outflow. In this paper, we present Very Large Telescope (VLT) measurements of the linear polarization of the optical light of jetted TDE Swift J2058+0516. This is the second jetted TDE studied in this manner, after Swift J1644+57. We find evidence of non-zero optical linear polarization, $P_{V}\sim 8{{\, \rm per\, cent}}$, a level very similar to the near-infrared polarimetry of Swift J1644+57. These detections provide an independent test of the emission mechanisms of the multiwavelength emission of jetted TDEs.

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