Andrei Nomerotski, Paul Stankus, Anže Slosar, Stephen Vintskevich, Shane Andrewski, Gabriella Carini, Denis Dolzhenko, Duncan England, Eden Figueroa, Sonali Ger… 展开作者
Andrei Nomerotski, Paul Stankus, Anže Slosar, Stephen Vintskevich, Shane Andrewski, Gabriella Carini, Denis Dolzhenko, Duncan England, Eden Figueroa, Sonali Gera, Justine Haupt, Sven Herrmann, Dimitrios Katramatos, Michael Keach, Alexander Parsells, Olli Saira, Jonathan Schiff, Peter Svihra, Thomas Tsang, Yingwen Zhang
备注：
intended for SPIE Astronomical Telescopes + Instrumentation 2020 conference
发表信息：
SPIE Proceedings Volume 11446, Optical and Infrared Interferometry and Imaging VII; 1144617 (2020)
It has been recently suggested that optical interferometers may not require a phase-stable optical link between the stations if instead sources of quantum-mechanically entangled pairs could be provided to them, enabling extra-long baselines and benefiting numerous topics in astrophysics and cosmology. We developed a new variation of this idea, proposing that photons from two different sources could be interfered at two decoupled stations, requiring only a slow classical connection between them. We show that this approach could allow high-precision measurements of the relative astrometry of the two sources, with a simple estimate giving angular resolution of $10 \ μ$as in a few hours' observation of two bright stars. We also give requirements on the instrument for these observations, in particular on its temporal and spectral resolution. Finally, we discuss possible technologies for the instrument implementation and first proof-of-principle experiments.
Quantum networks provide a platform for astronomical interferometers capable of imaging faint stellar objects. In a recent work [arXiv:1809.01659], we presented a protocol that circumvents transmission losses with efficient use of quantum resources and modest quantum memories. Here we analyze a number of extensions to that scheme. We show that it can be operated as a truly broadband interferometer and generalized to multiple sites in the array. We also analyze how imaging based on the quantum Fourier transform provides improved signal-to-noise ratio compared to classical processing. Finally, w…
Betelgeuse has gone through a sudden shift in its brightness and dimmed mysteriously. This is likely caused by a hot blob of plasma ejected from Betelgeuse and then cooled to obscuring dust. If true, it is a remarkable opportunity to directly witness the formation of dust around a red supergiant star. Today's optical telescope facilities are not optimized for time-evolution monitoring of the Betelgeuse surface, so in this work, we propose a low-cost optical interferometer. The facility will consist of $12 \times 4$ inch optical telescopes mounted on the surface of a large radio dish for interf…
The characterisation of exoplanets is critical to understanding planet diversity and formation, their atmospheric composition and the potential for life. This endeavour is greatly enhanced when light from the planet can be spatially separated from that of the host star. One potential method is nulling interferometry, where the contaminating starlight is removed via destructive interference. The GLINT instrument is a photonic nulling interferometer with novel capabilities that has now been demonstrated in on-sky testing. The instrument fragments the telescope pupil into sub-apertures that are i…
We discuss the design, construction, and operation of a new intensity interferometer, based on the campus of Southern Connecticut State University in New Haven, Connecticut. While this paper will focus on observations taken with an original two-telescope configuration, the current instrumentation consists of three portable 0.6-m Dobsonian telescopes with single-photon avalanche diode (SPAD) detectors located at the Newtonian focus of each telescope. Photons detected at each station are time-stamped and read out with timing correlators that can give cross-correlations in timing to a precision o…
This paper shall provide a summary of not yet published technical innovations to the GREGOR Fabry-Perot Interferometer (GFPI) at the 1.5m GREGOR Solar Telescope (Europe's largest solar telescope) that I implemented in 2013 as the Instrument Scientist of the GFPI. It also represents an overview of important and not yet published observational results that I achieved with the GFPI in 2013. The results and achievements can be considered a milestone in the further development, scientific verification and final acceptance of this instrument. The instrument is now in operation and employed by the in…
This article describes the operation of the near-infrared wavefront sensing based Adaptive Optics (AO) system CIAO. The Coudé Infrared Adaptive Optics (CIAO) system is a central auxiliary component of the Very Large Telescope (VLT) interferometer (VLTI). It enables in particular the observations of the Galactic Center (GC) using the GRAVITY instrument. GRAVITY is a highly specialized beam combiner, a device that coherently combines the light of the four 8-m telescopes and finally records interferometric measurements in the K-band on 6 baselines simultaneously. CIAO compensates for phase distur…
PAON4 is an L-band (1250-1500 MHz) small interferometer operating in transit mode deployed at the Nançay observatory in France, designed as a prototype instrument for Intensity Mapping. It features four 5~meter diameter dishes in a compact triangular configuration, with a total geometric collecting area of $\sim75 \mathrm{m^2}$, and equipped with dual polarization receivers. A total of 36 visibilities are computed from the 8 independent RF signals by the software correlator over the full 250~MHz RF band. The array operates in transit mode, with the dishes pointed toward a fixed declination, wh…
Demonstrating the integration of a photonic lantern with an all-fiber-based nulling interferometer
Univ. of California, Santa Cruz（加州大学圣克鲁兹分校）；Univ. of California, Los Angeles（加州大学洛杉矶分校）；NASA Ames Research Center（NASA艾姆斯研究中心）；NASA Glenn Research Center（NASA格伦研究中心）；Univ. of Central Florida（中佛罗里达大学）
Modeling the optical point spread function (PSF) is particularly challenging for adaptive optics (AO)-assisted observations owing to the its complex shape and spatial variations. We aim to (i) exhaustively demonstrate the accuracy of a recent analytical model from comparison with a large sample of imaged PSFs, (ii) assess the conditions for which the model is optimal, and (iii) unleash the strength of this framework to enable the joint estimation of atmospheric parameters, AO performance and static aberrations. We gathered 4812 on-sky PSFs obtained from seven AO systems and used the same fitti…
Imaging spectropolarimetry is an important observational tool in solar physics because of fast-cadence spectral scans with high-spectral resolution, large field-of-view, and its inherent suitability for post-facto image restoration. Fabry-Pérot etalons are the key optical elements of these instruments. Their optical quality critically defines the instrument's performance. The two etalons of the GREGOR Fabry-Pérot Interferometer (GFPI) were used for more than 10~years, raising questions about the potential deterioration of etalons coatings. We present an assessment of the etalons optical qualit…
FIRST, the Fibered Imager foR a Single Telescope, is a spectro-imager using single-mode fibers for pupil remapping, allowing measurements beyond the telescope diffraction limit. Integrated on the Subaru Coronagraphic Extreme Adaptive Optics instrument at the Subaru Telescope, it benefits from a very stable visible light wavefront allowing to acquire long exposure and operate on significantly fainter sources than previously possible. On-sky results demonstrated the ability of the instrument to detect stellar companions separated 43mas in the case of the Capella binary system. A similar approach…
The VERITAS Imaging Atmospheric Cherenkov Telescope array (IACT) was augmented in 2019 with high-speed focal plane electronics to create a new Stellar Intensity Interferometry (SII) observational capability (VERITAS-SII, or VSII). VSII operates during bright moon periods, providing high angular resolution observations ( < 1 mas) in the B photometric band using idle telescope time. VSII has already demonstrated the ability to measure the diameters of two B stars at 416 nm (Bet CMa and Eps Ori) with < 5% accuracy using relatively short (5 hours) exposures. The VSII instrumentation was recently i…
We study the impact of sky-based calibration errors from source mismodeling on 21\,cm power spectrum measurements with an interferometer and propose a method for suppressing their effects. While emission from faint sources that are not accounted for in calibration catalogs is believed to be spectrally smooth, deviations of true visibilities from model visibilities are not, due to the inherent chromaticity of the interferometer's sky-response (the "wedge"). Thus, unmodeled foregrounds, below the confusion limit of many instruments, introduce frequency structure into gain solutions on the same l…
Phase masks have numerous applications in astronomical optics, in particular related to two themes: coronography for detection and analysis of extrasolar planets or circumstellar disks, and wavefront analysis for extremely precise adaptive optics systems or cophasing of segmented mirrors. I review some of the literature concerning phase masks and attempt to bridge the gap between two instrumental systems in which they are often found: the Mach-Zehnder interferometer and the coronograph.
The Very Large Telescope Interferometer is one of the most proficient observatories in the world for high angular resolution. Since its first observations, it has hosted several interferometric instruments operating in various bandwidths in the infrared. As a result, the VLTI has yielded countless discoveries and technological breakthroughs. Here, we introduce a new concept for the VLTI, Asgard: an instrumental suite comprised of four natively collaborating instruments: BIFROST, a combiner whose main science case is studying the formation processes and properties of stellar and planetary syste…
Compact interferometers, called phasemeters, make it possible to operate over a large range while ensuring a high resolution. Such performance is required for the stabilization of large instruments dedicated to experimental physics such as gravitational wave detectors. This paper aims at presenting the working principle of the different types of phasemeters developed in the literature. These devices can be classified into two categories: homodyne and heterodyne interferometers. Improvement of resolution and accuracy has been studied for both devices. Resolution is related to the noise sources …
The Large Interferometer For Exoplanets (LIFE) initiative is developing the science and a technology roadmap for an ambitious space mission featuring a space-based mid-infrared (MIR) nulling interferometer in order to detect the thermal emission of hundreds of exoplanets and characterize their atmospheres. In order to quantify the science potential of such a mission, in particular in the context of technical trade-offs, an instrument simulator is required. In addition, signal extraction algorithms are needed to verify that exoplanet properties (e.g., angular separation, spectral flux) containe…
Phase-shifting technique for improving the imaging capacity of sparse-aperture optical interferometers
在本文中，我们描述了一个多孔径干涉仪的原理，使用相移技术，并适用于快速，快照成像的天体物理对象在极端的角分辨率通过傅立叶反演。所提出的设计的几个优点突出，其中包括辐射效率，领域的Fizeau干涉仪，和一个初步的校准程序，允许表征仪器误差。对于大的望远镜数量，所提出的设计也导致在相当大的简化的光学和机械设计。数值模拟表明，仅使用传统光学组件或新兴技术，就可以将数百台望远镜耦合到单个4K x 4K探测器阵列上。
Ground based low frequency radio interferometers have been developed in the last decade and are providing the scientific community with high quality observations. Conversely, current radioastronomy instruments in space have a poor angular resolution with single point observation systems. Improving the observation capabilities of the low frequency range (a few kHz to 100 MHz) requires to go to space and to set up a space based network of antenna that can be used as an interferometer. We present the outcome of the NOIRE (Nanosatellites pour un Observatoire Interférométrique Radio dans l'Espace /…
The 21-cm signal of neutral hydrogen - emitted during the Epoch of Reionization - promises to be an important source of information for the study of the infant universe. However, its detection is impossible without sufficient mitigation of other strong signals in the data, which requires an accurate knowledge of the instrument. Using the result of instrument calibration, a large part of the contaminating signals are removed and the resulting residual data is further analyzed in order to detect the 21-cm signal. Direction dependent calibration (DDC) can strongly affect the 21-cm signal, however…
We report on the detection of source noise in the time domain at 162MHz with the Murchison Widefield Array. During the observation the flux of our target source Virgo A (M87) contributes only $\sim$1\% to the total power detected by any single antenna, thus this source noise detection is made in an intermediate regime, where the source flux detected by the entire array is comparable with the noise from a single antenna. The magnitude of source noise detected is precisely in line with predictions. We consider the implications of source noise in this moderately strong regime on observations with…
Development of Fiber Fabry-Perot Interferometers as Stable Near-infrared Calibration Sources for High Resolution Spectrographs
我们讨论了单模光纤法布里-珀罗（FFP）干涉仪作为高精度径向速度（RV）光谱仪的精确天文光子校准源的持续发展。FFP是简单、廉价的单片单元，可以产生稳定和可重复的输出光谱。FFP是传统标准具的独特替代品，因为干涉腔由单模光纤而不是气隙间隔器制成。这种设计允许出色的准直，高光谱精细度，刚性机械稳定性，对振动不敏感，并且不需要真空操作。我们测试的设备是Micron Optics的市售产品。我们的发展道路是针对校准源的可扩展区行星光谱仪（HPF），近红外光谱仪，旨在检测低质量恒星周围的地球质量行星，但这个参考也可以用于许多现有的和计划中的光纤光谱仪，因为我们说明使用Apache点天文台星系演化实验（APOGEE）仪器。通过对光纤标准具的精确温度控制，我们实现了100 $μ$ K的热稳定性和22 cm s $^{-1}$的相关速度不确定性。我们实现了$\approx$ 2 m s $^{-1}$的精度在一个单一的APOGEE光纤超过12小时，使用这个新的光子参考后，删除系统的相关性。这种高精度（接近预期的光子极限下限）证明了光纤干涉仪出色的固有波长稳定性和APOGEE仪器设计的稳定性。当在所有300个APOGEE光纤上取平均值并去除已知趋势和压力相关性后，12小时内的总体仪器速度精度为80 cm s $^{-1}$，这意味着光纤标准具在本质上稳定到显著更高的精度。
HIRMES is a far-infrared spectrometer that was chosen as the third generation instrument for NASA's SOFIA airborne observatory. HIRMES promises background limited performance in four modes that cover the wavelength range between 25 and 122 $μ$m. The high-spectral resolution ($R \approx 10^5$) mode is matched to achieve maximum sensitivity on velocity-resolved lines to study the evolution of protoplanetary disks. The mid-resolution ($R \approx 12, 000$) mode is suitable for high sensitivity imaging of galactic star formation regions in, for example, the several far-infrared fine structure lines…
Imaging Atmospheric Cherenkov Telescopes have long been viewed as potential light collectors to be used for long baseline optical intensity interferometry observations. Intensity interferometry, as implemented with Cherenkov telescopes, is well suited for studying the spatial structure of stars of O/B/A stellar types at short optical wavelengths. Such observations complement those with the current generation of optical amplitude interferometers, which are typically restricted to longer wavelengths. Dedicated intensity interferometry instrumentation has been developed for the VERITAS observator…
Pushing high angular resolution and high contrast observations on the VLTI from Y to L band with the Asgard instrumental suite: integration status and plans
Spectral features introduced by instrumental chromaticity of radio interferometers have the potential to negatively impact the ability to perform Epoch of Reionisation (EoR) and Cosmic Dawn (CD) science using the redshifted neutral hydrogen emission line from the early Universe. We describe instrument calibration choices that influence the spectral characteristics of the science data, and assess their impact on EoR statistical and tomographic experiments. Principally, we consider the intrinsic spectral response of the receiving antennas, embedded within a complete frequency-dependent primary b…
