相关论文: Calibrating Iodine Cells for Precise Radial Veloci…
We present high-resolution spectroscopy of Iodine vapour that is loaded and trapped within the core of a hollow-core photonic crystal fibre (HC-PCF). We compare the observed spectroscopic features to those seen in a conventional iodine cell…
The technique of line depth ratios (LDR) is one of the methods to determine the effective temperature of a star. They are crucial in the spectroscopic studies of variable stars like Cepheids since no simultaneous photometry is usually…
The accurate flux calibration of observational data is vital for astrophysics and cosmology because absolute flux uncertainties of stellar standards propagate into scientific results. With the ever higher precision achieved by telescopic…
This study analyzed the optical techniques for high resolution, low-noise spectroscopy of a hyperfine structure (HFS) made of ytterbium-isotope 171 ions ($^{171}\mathrm{Yb}^{3+}$:$\mathrm{Y}_2\mathrm{SiO}_5$). Large energy spacings in…
An empirical model has been developed to reproduce the drift of the spectrum recorded by EIS on board Hinode using instrumental temperatures and relative motion of the spacecraft. The EIS spectrum shows an artificial drift in wavelength…
Modern precise radial velocity spectrometers are designed to infer the existence of planets orbiting other stars by measuring few-nm shifts in the positions of stellar spectral lines recorded at high spectral resolution on a large-area…
Aims: We evaluate the radial velocity (RV) information content and achievable precision on M0-M9 spectra covering the ZYJHK bands. We do so while considering both a perfect atmospheric transmission correction and discarding areas polluted…
When optically excited, iodine absorbs in the 490- to 650-nm visible region of the spectrum and, after radiative relaxation, it displays an emission spectrum of discrete vibrational bands at moderate resolution. This makes laser-induced…
We demonstrate the ability to measure precise stellar barycentric radial velocities with the dispersed fixed-delay interferometer technique using the Exoplanet Tracker (ET), an instrument primarily designed for precision differential…
One of the key ingredients in establishing the relation between input signal and output flux from a spectrometer is accurate determination of the spectrophotometric calibration. In the case of spectrometers onboard satellites, the accuracy…
We found that temperature-dependent infrared spectroscopy measurements (i.e., reflectance or transmittance) using a Fourier-transform spectrometer can have substantial errors, especially for elevated sample temperatures and collection using…
The current generation of precision radial velocity (RV) spectrographs are seeing-limited instruments. In order to achieve high spectral resolution on 8m class telescopes, these spectrographs require large optics and in turn, large…
presented. The 2.38 -- 4.08 micron wavelength-range of band 1 of ISO-SWS (Short-Wavelength Spectrometers on board of the Infrared Space Observatory) in which many different molecules -- with their own dependence on each of the stellar…
We present 10 - 19 um moderate resolution spectra of ten M dwarfs, one L dwarf, and two T dwarf systems obtained with the Infrared Spectrograph (IRS) onboard the Spitzer Space Telescope. The IRS allows us to examine molecular spectroscopic…
The determination of effective temperatures of very hot central stars (Teff>70000K) by model atmosphere analyses of optical H and He line profiles is afflicted with considerable uncertainty, primarily due to the lack of neutral helium…
Doppler spectroscopy has uncovered or confirmed all the known planets orbiting nearby stars. Two main techniques are used to obtain precision Doppler measurements at optical wavelengths. The first approach is the gas cell method, which…
We present results from the commissioning and early science programs of FIDEOS, the new high-resolution echelle spectrograph developed at the Centre of Astro Engineering of Pontificia Universidad Catolica de Chile, and recently installed at…
Sub-milliarcsecond imaging of nearby main sequence stars and binary systems can provide critical information on stellar phenomena such as rotational deformation, accretion effects, and the universality of starspot (sunspot) cycles.…
Spectral CT offers enhanced material discrimination over single-energy systems and enables quantitative estimation of basis material density images. Water/iodine decomposition in contrast-enhanced CT is one of the most widespread…
Precision measurements of the Sunyaev-Zel'dovich effect in clusters of galaxies require excellent rejection of common-mode signals and wide frequency coverage. We describe an imaging, efficient, differential Fourier transform spectrometer…