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Accurate stellar parameters are needed in numerous domains of astrophysics. The position of stars on the H-R diagram is an important indication of their structure and evolution, and it helps improve stellar models. Furthermore, the age and…

The formation scenario for massive stars is still under discussion. To further constrain current theories, it is vital to spatially resolve the structures from which material accretes onto massive young stellar objects (MYSOs). Due to the…

Solar and Stellar Astrophysics · Physics 2015-05-19 R. Follert , H. Linz , B. Stecklum , R. van Boekel , Th. Henning , M. Feldt , T. M. Herbst , Ch. Leinert

We proposed a novel approach to coherent imaging of dynamic samples. The inter-frame similarity of the sample's local structures is found to be a powerful constraint in phasing a sequence of diffraction patterns. We devised a new image…

Optics · Physics 2024-07-11 Pengju Sheng , Fucai Zhang

We have designed and constructed a ``dispersed Fourier Transform Spectrometer'' (dFTS), consisting of a conventional FTS followed by a grating spectrometer. By combining these two devices, we negate a substantial fraction of the sensitivity…

The principles and practice of astronomical imaging Fourier transform spectroscopy (FTS) at far-infrared wavelengths are described. The Mach-Zehnder interferometer design has been widely adopted for current and future imaging FTS…

Instrumentation and Methods for Astrophysics · Physics 2013-10-10 David A. Naylor , Brad G. Gom , Matthijs H. D. van der Wiel , Gibion Makiwa

The very inner structure of massive YSOs is difficult to trace. With conventional observational methods we often identify structures still several hundreds of AU in size. But we also need information about the innermost regions where the…

Astrophysics · Physics 2008-04-01 H. Linz , Th. Henning , B. Stecklum , A. Men'shchikov , R. van Boekel , R. Follert , M. Feldt

We discuss our new implementation of the Real-space Electronic Structure method for studying the atomic and electronic structure of infinite periodic as well as finite systems, based on density functional theory. This improved version which…

Materials Science · Physics 2009-10-31 U. V. Waghmare , Hanchul Kim , I. J. Park , Normand Modine , P. Maragakis , Efthimios Kaxiras

Grid stars and reference stars provide the fundamental global and local astrometric reference frames for observations by the Space Interferometry Mission. They must therefore be astrometrically stable at the ~1 uas level. I present simple…

Astrophysics · Physics 2009-11-06 Andrew Gould

Far-infrared (FIR) and mid-infrared (MIR) fine-structure lines (FSLs) provide key diagnostics of physical conditions in the interstellar medium (ISM). Building on empirical relations established in our previous work, we use photoionization…

Astrophysics of Galaxies · Physics 2025-07-17 Bo Peng , Amit Vishwas , Cody Lamarche , Gordon Stacey , Catie Ball , Christopher Rooney , Thomas Nikola , Carl Ferkinhoff

FORUM (Far-infrared Outgoing Radiation Understanding and Monitoring) was selected in 2019 as the ninth Earth Explorer mission by the European Space Agency (ESA). Its primary objective is to collect interferometric measurements in the…

Atmospheric and Oceanic Physics · Physics 2024-10-31 Cristina Sgattoni , Luca Sgheri , Matthias Chung

Radiation symmetry evaluation is critical to the laser driven Inertial Confinement Fusion (ICF), which is usually done by solving a view-factor equation model. The model is nonlinear, and the number of equations can be very large when the…

Signal Processing · Electrical Eng. & Systems 2019-08-20 Yanfeng Zhang

In an era of unprecedented deluge of (mostly unstructured) data, graphs are proving more and more useful, across the sciences, as a flexible abstraction to capture complex relationships between complex objects. One of the main challenges…

Disordered Systems and Neural Networks · Physics 2016-10-17 Alaa Saade

Coherent anti-Stokes Raman Spectroscopy (CARS) is a laser-based measurement technique widely applied across many science and engineering disciplines to perform non-intrusive gas diagnostics. CARS is often used to study combustion, where the…

Machine Learning · Computer Science 2022-05-25 Gregory J. Hunt , Cody R. Ground , Andrew D. Cutler

Radio interferometers have the ability to precisely localize and better characterize the properties of sources. This ability is having a powerful impact on the study of fast radio transients, where a few milliseconds of data is enough to…

Instrumentation and Methods for Astrophysics · Physics 2018-05-23 C. J. Law , G. C. Bower , S. Burke-Spolaor , B. J. Butler , P. Demorest , A. Halle , S. Khudikyan , T. J. W. Lazio , M. Pokorny , J. Robnett , M. Rupen

Fast radio bursts (FRBs) are luminous, millisecond-duration transients that offer great potential for probing the universe, yet their physical origins remain unclear. The dispersion measure (DM) and scattering time ($\tau$) distributions…

High Energy Astrophysical Phenomena · Physics 2025-06-24 Jian-Feng Mo , Weishan Zhu , Long-Long Feng

Information about the physical properties of astrophysical objects cannot be measured directly but is inferred by interpreting spectroscopic observations in the context of atomic physics calculations. Ratios of emission lines, for example,…

Context. Indirect observations of the cosmic-ray electron (CRE) distribution via synchrotron emission is crucial for deepening the understanding of the CRE transport in the interstellar medium, and in investigating the role of galactic…

High Energy Astrophysical Phenomena · Physics 2023-01-24 Julien Dörner , Patick Reichherzer , Julia Becker Tjus , Volker Heesen

To avoid decorrelation, conventional synthetic aperture radar interferometry (InSAR) requires that interferometric images should have a common spectral band and the same resolution after proper preprocessing. For a high-resolution (HR)…

Signal Processing · Electrical Eng. & Systems 2020-10-15 Huizhang Yang , Chengzhi Chen , Shengyao Chen , Feng Xi , Zhong Liu

We use spectrally dispersed near-IR interferometry data to constrain the temperature profiles of sub-AU-sized regions of 11 Herbig Ae/Be sources. We find that a single-temperature ring does not reproduce the data well. Rather, models…

Astrophysics · Physics 2008-11-26 J. A. Eisner , E. I. Chiang , B. F. Lane , R. L. Akeson

We describe a technique for deriving effective temperatures, surface gravities, rotation velocities, and radial velocities from high resolution near-IR spectra. The technique matches the observed near-IR spectra to spectra synthesized from…

Astrophysics · Physics 2009-11-10 G. W. Doppmann , D. T. Jaffe