Development of a Near-Infrared Echelle Spectrograph “NICE”

Abstract We present updated radial-velocity (RV) analyses of the AU Mic system. AU Mic is a young (22 Myr) early-M dwarf known to host two transiting planets—P b ∼ 8.46 days, R b = 4.38 − 0.18 + 0.18 R ⊕ , P c ∼ 18.86 days, R c = 3.51 − 0.16 + 0.16 R ⊕ . With visible RVs from Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical echelle Spectrographs (CARMENES)-VIS, CHIRON, HARPS, HIRES, Minerva-Australis, and Tillinghast Reflector Echelle Spectrograph, as well as near-infrared (NIR) RVs from CARMENES-NIR, CSHELL, IRD, iSHELL, NIRSPEC, and SPIRou, we provide a 5σ upper limit to the mass of AU Mic c of M c ≤ 20.13 M ⊕ and present a refined mass of AU Mic b of M b = 20.12 − 1.57 + 1.72 M ⊕ . Used in our analyses is a new RV modeling toolkit to exploit the wavelength dependence of stellar activity present in our RVs via wavelength-dependent Gaussian processes. By obtaining near-simultaneous visible and near-infrared RVs, we also compute the temporal evolution of RV “color” and introduce a regressional method to aid in isolating Keplerian from stellar activity signals when modeling RVs in future works. Using a multiwavelength Gaussian process model, we demonstrate the ability to recover injected planets at 5σ significance with semi-amplitudes down to ≈10 m s−1 with a known ephemeris, more than an order of magnitude below the stellar activity amplitude. However, we find that the accuracy of the recovered semi-amplitudes is ∼50% for such signals with our model.

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The University of Tokyo Atacama Observatory 6.5m telescope: update of the Near-Infrared Echelle Spectrograph NICE as the first light instrument

Ground-based and Airborne Instrumentation for Astronomy VIII ◽

10.1117/12.2561186 ◽

2020 ◽

Author(s):

Kentaro Asano ◽

Masuo Tanaka ◽

Hidenori Takahashi ◽

Hiroaki Sameshima ◽

Atsushi Nishimura ◽

...

Keyword(s):

Near Infrared ◽

Echelle Spectrograph ◽

The University

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GOHSS: A MOS fiber-fed multi-echelle spectrograph in the near infrared (0.9-1.8 μm)

10.1117/12.458948 ◽

2003 ◽

Cited By ~ 1

Author(s):

Dario Lorenzetti ◽

Fausto Cortecchia ◽

Francesco D'Alessio ◽

Agostino Fiorani ◽

Gianluca Li Causi ◽

...

Keyword(s):

Near Infrared ◽

Echelle Spectrograph

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Stellar population astrophysics (SPA) with the TNG

Astronomy and Astrophysics ◽

10.1051/0004-6361/202039397 ◽

2020 ◽

Vol 645 ◽

pp. A19

Author(s):

C. Fanelli ◽

L. Origlia ◽

E. Oliva ◽

A. Mucciarelli ◽

N. Sanna ◽

...

Keyword(s):

High Resolution ◽

Stellar Population ◽

Near Infrared ◽

Chemical Species ◽

Chemical Properties ◽

High Resolution Spectroscopy ◽

Diagnostic Tools ◽

Echelle Spectrograph ◽

Chemical Abundances ◽

Molecular Lines

Context. High-resolution spectroscopy in the near-infrared (NIR) is a powerful tool for characterising the physical and chemical properties of cool-star atmospheres. The current generation of NIR echelle spectrographs enables the sampling of many spectral features over the full 0.9–2.4 μm range for a detailed chemical tagging. Aims. Within the Stellar Population Astrophysics Large Program at the TNG, we used a high-resolution (R = 50 000) NIR spectrum of Arcturus acquired with the GIANO-B echelle spectrograph as a laboratory to define and calibrate an optimal line list and new diagnostic tools to derive accurate stellar parameters and chemical abundances. Methods. We inspected several hundred NIR atomic and molecular lines to derive abundances of 26 different chemical species, including CNO, iron-group, alpha, Z-odd, and neutron-capture elements. We then performed a similar analysis in the optical using Arcturus VLT-UVES spectra. Results. Through the combined NIR and optical analysis we defined a new thermometer and a new gravitometer for giant stars, based on the comparison of carbon (for the thermometer) and oxygen (for the gravitometer) abundances, as derived from atomic and molecular lines. We then derived self-consistent stellar parameters and chemical abundances of Arcturus over the full 4800–24 500 Å spectral range and compared them with previous studies in the literature. We finally discuss a number of problematic lines that may be affected by deviations from thermal equilibrium and/or chromospheric activity, as traced by the observed variability of He I at 10 830 Å.

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Design for a near-infrared immersion echelle spectrograph: breaking the R=100,000 barrier from 1.5 to 5 μm

10.1117/12.317312 ◽

1998 ◽

Cited By ~ 1

Author(s):

Luke D. Keller ◽

Daniel T. Jaffe ◽

Greg W. Doppmann

Keyword(s):

Near Infrared ◽

Echelle Spectrograph

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Model studies on vibrationally-rotationally excited hydroxyl molecules in the mesopause region

10.5194/egusphere-egu2020-15350 ◽

2020 ◽

Author(s):

Justus Notholt ◽

Holger Winkler ◽

Stefan Noll

Keyword(s):

Near Infrared ◽

Measurement Data ◽

Model Parameters ◽

Chemical Production ◽

Echelle Spectrograph ◽

Mesopause Region ◽

Rotational States ◽

Model Studies ◽

Temperature Component ◽

Remotely Sense

<p>One of the standard methods to remotely sense the temperature of the mesopause region is based on spectroscopic measurements of near-infrared emissions of vibrationally-rotationally excited hydroxyl molecules, and to calculate &#160;rotational temperatures. For the interpretation of the retrieved temperatures, the aspect of rotational thermalization is of great importance. We present results of a first-principle kinetic model of vibrationally-rotationally excited hydroxyl molecules which accounts for chemical production and loss processes as well as radiative and collision-induced vibrational-rotational transitions. The model allows one to assess deviations of the rotational populations from local thermodynamic equilibrium, and to identify the key parameters which control the rotational thermalization processes. The model simulations reproduce the observed bimodality in temperatures, i.e. a cold temperature component dominating the population of low rotational states, and a hot temperature component dominating higher states. The model results are compared to measurement data from the UVES echelle spectrograph at Cerro Paranal in Chile (Presentation EGU2020-3169) which allows us to confine free model parameters such as the rotational state changes in vibrational quenching process.</p>

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Properties of OH roto-vibrational level populations in the Earth's mesopause region

10.5194/egusphere-egu2020-3169 ◽

2020 ◽

Author(s):

Stefan Noll ◽

Holger Winkler ◽

Oleg Goussev ◽

Bastian Proxauf

Keyword(s):

Vibrational Level ◽

Near Infrared ◽

Population Distribution ◽

Echelle Spectrograph ◽

Emission Layer ◽

Mesopause Region ◽

Important Indicator ◽

Infrared Wavelength ◽

Cold Component ◽

Upper Level

<p>Chemiluminescent OH airglow emission dominates the nighttime radiation of the Earth's atmosphere in the near-infrared wavelength regime. It is an important indicator of the state and variability of the mesopause region at about 90 km. However, the interpretation of the line intensities suffers from uncertainties in the knowledge of the complex roto-vibrational level population distribution, which is far from local thermodynamic equilibrium (LTE). For a better understanding, we investigated these populations in detail mainly based on a high-quality high-resolution mean spectrum from the UVES echelle spectrograph at Cerro Paranal in Chile, which allowed us to measure about 1,000 individual lines including numerous resolved &#923;-doublet components between 560 and 1060 nm. As the quality of the currently available sets of OH Einstein-A coefficients is not sufficient for accurate population retrievals, we derived an improved set by a semi-empirical approach, which benefited from the measurement of multiple lines with the same upper level. The resulting populations indicate a clear bimodality for each vibrational level, which is characterised by a cold component indicating the ambient temperature at the OH layer heights and a hot non-LTE component dominating high rotational levels. Our promising two-population fits allowed us to constrain the non-LTE contributions to rotational temperatures based on lines with upper states with low rotational and fixed vibrational quantum number, which are widely used to estimate temperatures in the mesopause region. The bimodality is also clearly indicated by the different population changes depending on the effective altitude of the OH emission layer. Only the cold component significantly decreases with increasing altitude. Our results will be very useful for the challenging modelling of the OH thermalisation process.</p>

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