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The very recent years have seen a promising start in scientific publications making use of images produced by near-infrared long-baseline interferometry. The technique has reached, at last, a technical maturity level that opens new avenues…

天体物理仪器与方法 · 物理学 2015-05-13 M. Benisty , J-P. Berger , L. Jocou , P. Labeye , F. Malbet , K. Perraut , P. Kern

While VLBI experiments at 3mm are nowadays fairly standard, VLBI at 1mm still is technically difficult. Here we summarize the results from previous VLBI pilot experiments at 1.3mm. These included antennas at IRAM (Pico Veleta, Plateau de…

天体物理学 · 物理学 2007-05-23 S. Doeleman , T. P. Krichbaum

Very Long Baseline Interferometry (VLBI) astrometry is a well established technique for achieving $\pm10~\mu$as parallax accuracies at frequencies well above 10~GHz. At lower frequencies, uncompensated interferometer delays associated with…

We discuss possibilities and improvements which could be obtained, if a phased array with a large number (N=50-100) of sub-millimeter antennas - like the planned large southern array (the former LSA, now ALMA) is used for…

天体物理学 · 物理学 2007-05-23 Thomas P. Krichbaum

We summarize the present status of VLBI experiments at 3 mm (86 GHz), 2 mm (129-150 GHz) and 1.3 mm (215-230 GHz). We present and discuss a new 3 mm VLBI map of M87 (Virgo A), which has a spatial resolution of only approx. 20 Schwarzschild…

VLBI is unique, among the space geodetic techniques, in its contribution to defining and maintaining the International Celestial Reference Frame, providing precise measurements of coordinates of extragalactic radiosources. The quest for…

天体物理学 · 物理学 2007-05-23 Maria J. Rioja , Richard Dodson , Richard W. Porcas , Hiroshi Suda , Francisco Colomer

For Very Long Baseline Interferometry (VLBI), the fringe spacing is extremely narrow compared to the field of view imposed by the primary beam of each element. This means that an extremely large number of resolution units can potentially be…

天体物理仪器与方法 · 物理学 2013-02-26 John S. Morgan , F. Mantovani , A. T. Deller , W. Brisken , W. Alef , E. Middelberg , M. Nanni , S. J. Tingay

Large-momentum-transfer~(LMT) atom interferometers using elastic Bragg scattering on light waves are among the most precise quantum sensors to date. To advance their accuracy from the mrad to the $\mu$rad regime, it is necessary to…

Interferometric imaging now achieves angular resolutions as fine as 10 microarcsec, probing scales that are inaccessible to single telescopes. Traditional synthesis imaging methods require calibrated visibilities; however, interferometric…

天体物理仪器与方法 · 物理学 2018-04-25 Andrew A. Chael , Michael D. Johnson , Katherine L. Bouman , Lindy L. Blackburn , Kazunori Akiyama , Ramesh Narayan

Simultaneous observations at multiple frequency bands have the potential to overcome the fundamental limitation imposed by the atmospheric propagation in mm-VLBI observations. The propagation effects place a severe limit in the sensitivity…

天体物理仪器与方法 · 物理学 2015-12-23 Maria J. Rioja , Richard Dodson , Taehyun Jung , Bong Won Sohn

The paper describes the peculiarities of acquirement and interpretation of images of current distribution through the sample surface when operating in I-AFM mode. It shows that I-AFM and SCM modes can be successfully used only for small…

仪器与探测器 · 物理学 2020-12-15 Olga V. Sviridova

Despite making significant progress in multi-modal tasks, current Multi-modal Large Language Models (MLLMs) encounter the significant challenge of hallucinations, which may lead to harmful consequences. Therefore, evaluating MLLMs'…

计算与语言 · 计算机科学 2024-02-26 Junyang Wang , Yuhang Wang , Guohai Xu , Jing Zhang , Yukai Gu , Haitao Jia , Jiaqi Wang , Haiyang Xu , Ming Yan , Ji Zhang , Jitao Sang

Photometric instruments operating at far infrared to millimetre wavelengths often have broad spectral passbands (central wavelength/bandwidth ~ 3 or less), especially those operating in space. A broad passband can result in significant…

The measurement precision of modern quantum simulators is intrinsically constrained by the limited set of measurements that can be efficiently implemented on hardware. This fundamental limitation is particularly severe for quantum…

量子物理 · 物理学 2020-07-01 Giacomo Torlai , Guglielmo Mazzola , Giuseppe Carleo , Antonio Mezzacapo

In the Aharonov-Albert-Vaidman (AAV) weak measurement, it is assumed that the measuring device or the pointer is in a quantum mechanical pure state. In reality, however, it is often not the case. In this paper, we generalize the AAV weak…

量子物理 · 物理学 2010-02-25 Young-Wook Cho , Hyang-Tag Lim , Young-Sik Ra , Yoon-Ho Kim

In this series of papers, we present new methods of frequency- and time-dependent instrumental polarization calibration for Very Long Baseline Interferometry (VLBI). In most existing calibration tools and pipelines, it has been assumed that…

天体物理仪器与方法 · 物理学 2023-10-06 Jongho Park , Keiichi Asada , Do-Young Byun

The VLTI instrument GRAVITY combines the beams from four telescopes and provides phase-referenced imaging as well as precision-astrometry of order 10 microarcseconds by observing two celestial objects in dual-field mode. Their angular…

Real-time searches for faint radio pulses from unknown radio transients are computationally challenging. Detections become further complicated due to continuously increasing technical capabilities of transient surveys: telescope…

天体物理仪器与方法 · 物理学 2018-11-13 Klim Mikhailov , Alessio Sclocco

The high angular resolution and sensitivity of Very Long Baseline Interferometry (VLBI) offer a unique tool to identify and study active galactic nuclei and star-formation activity over cosmic time. However, despite recent technical…

星系天体物理 · 物理学 2024-12-05 Célestin Herbé-George , J. P. Mckean , Raffaella Morganti , Jack F. Radcliffe

Accurate primary beam calibration is essential for precise brightness measurements in radio astronomy. The VLA Low-band Ionosphere and Transient Experiment (VLITE) faces challenges in calibration due to the offset Cassegrain optics used in…

天体物理仪器与方法 · 物理学 2024-12-20 Emil Polisensky , Tracy E. Clarke , Simona Giacintucci , Wendy Peters