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Frequency Phase Transfer (FPT) is a technique designed to increase coherence and sensitivity in radio interferometry by making use of the non-dispersive nature of the troposphere to calibrate high-frequency data using solutions derived at a…

The parameter space favourable for the resonant excitation of free oscillation modes by dynamic tides in close binary components is explored using qualitative considerations to estimate the order of magnitude of the tidal force and the…

Astrophysics · Physics 2009-11-10 B. Willems

Global 21-cm experiments are built to study the evolution of the Universe between the cosmic dawn and the epoch of reionisation. FlexKnot is a function parameterised by freely moving knots stringed together by splines. Adopting the FlexKnot…

Instrumentation and Methods for Astrophysics · Physics 2024-03-22 Emma Shen , Dominic Anstey , Eloy de Lera Acedo , Anastasia Fialkov

NMR measurements of the electron spin polarization have been performed on a 2D electron system at and around half-filled lowest Landau level. Comparing the magnetic field and the temperature dependence of the spin polarization to models of…

Mesoscale and Nanoscale Physics · Physics 2016-08-16 N. Freytag , M. Horvatić , C. Berthier , M. Shayegan , L. P. Lévy

We present measurements of proper motion of the sub-parsec scale jet at 22 GHz in the nearby FR I galaxy 3C 66B. Observations were made using the VLBA at six epochs over four years. A phase-referencing technique was used to improve the…

Astrophysics of Galaxies · Physics 2017-06-21 Hiroshi Sudou , Satoru Iguchi , Guang-Yao Zhao

Most cosmological parameters are expected to change significantly only on cosmological time scales, but given the large amount of information contained within the Cosmic Microwave Background (CMB) sky, we can expect that changes in the CMB…

Astrophysics · Physics 2008-12-18 Adam Moss , James P. Zibin , Douglas Scott

We report the detection of a long-timescale negative lag, where the blue bands lag the red bands, in the nearby Seyfert 1 galaxy Fairall 9. Active Galactic Nuclei (AGN) light curves show variability over a wide range of timescales. By…

Astrophysics of Galaxies · Physics 2023-08-09 Philippe Z. Yao , Amy Secunda , Yan-Fei Jiang , Jenny E. Greene , Ashley Villar

We present the multi-frequency, multi-epoch Very Long Baseline Interferometry (VLBI) study of the two-sided jets in the low-luminosity active galactic nucleus NGC 3998, where physical properties of the jets on parsec scales remain poorly…

Astrophysics of Galaxies · Physics 2025-03-13 Xi Yan , Lang Cui , Luis C. Ho

A general method for obtaining the oscillation periods of the interlayer exchange coupling is presented. It is shown that it is possible for the coupling to oscillate with additional periods beyond the ones predicted by the RKKY theory. The…

Strongly Correlated Electrons · Physics 2009-10-28 M. S. Ferreira , J. d'Albuquerque e Castro , D. M. Edwards , J. Mathon

In this paper, standard accretion disk models of AGNs are tested using light curves of 26 objects well observed for reverberation mapping. Time scales of variations are estimated by the most common definition of the variability time scale…

Astrophysics · Physics 2014-01-10 H. T. Liu , J. M. Bai , X. H. Zhao , L. Ma

Polarized synchrotron emission from ultra-relativistic electrons spiraling the Galactic magnetic field has become one of the most relevant emissions in the Interstellar medium these last years due to the improvement in the quality of…

We study Friedel oscillations and screening effects of the impurity potential in the Hubbard model. Electronic correlations are accounted for by solving the real-space dynamical mean-field theory equations using the continuous time quantum…

Strongly Correlated Electrons · Physics 2019-09-18 B. Chatterjee , J. Skolimowski , K. Makuch , K. Byczuk

Polarized Galactic synchrotron emission is an undesirable foreground for cosmic microwave background (CMB) experiments observing at frequencies $< 150$ GHz. We perform a combined analysis of observational data at 1.4, 2.3, 23, 30 and 33 GHz…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-07 Janet L. Weiland , Graeme E. Addison , Charles L. Bennett , Mark Halpern , Gary Hinshaw

We analysed the four-decades-long X-ray light curve of the low-luminosity active galactic nucleus (LLAGN) NGC 7213 and discovered a fast-rise-exponential-decay (FRED) pattern, i.e. the X-ray luminosity increased by a factor of $\approx 4$…

High Energy Astrophysical Phenomena · Physics 2018-01-31 Zhen Yan , Fu-Guo Xie

Context: A turbulent atmosphere causes atmospheric piston variations leading to rapid changes in the optical path difference of an interferometer, which causes correlated flux losses. This leads to decreased sensitivity and accuracy in the…

Instrumentation and Methods for Astrophysics · Physics 2014-09-05 A. Müller , J. -U. Pott , A. Mérand , R. Abuter , F. Delplancke-Ströbele , Th. Henning , R. Köhler , Ch. Leinert , S. Morel , T. Phan Duc , E. Pozna , A. Ramirez , J. Sahlmann , C. Schmid

Tidal friction has long been recognized to circularize the orbits of binary stars over time. In this study, we use the observed distribution of orbital eccentricities in populations of binary stars to probe tidal dissipation. In contrast to…

Solar and Stellar Astrophysics · Physics 2022-09-26 Kaloyan M. Penev , Joshua A. Schussler

In this second paper on our variability survey of central stars of planetary nebulae (CSPNe) using ZTF, we report 11 long-timescale variables with variability timescales ranging from months to years. We also present preliminary analyses…

We use cosmological simulations of reionization to predict the possible signal from the redshifted 21 cm line of neutral hydrogen in the pre-reionization era and to investigate the observability of this signal. We show that the separation…

Astrophysics · Physics 2009-11-10 Nickolay Y. Gnedin , Peter A. Shaver

We study the Faraday rotation measure (RM) variability of flat spectrum radio quasar 1633+382 on 5 epochs spanning from 2004 to 2008. We used 4 to 43~GHz VLBI polarization data from VLBA. Core RM across 4 to 15 GHz scales with a power index…

High Energy Astrophysical Phenomena · Physics 2025-05-07 Kah Chun Lai , Juan Carlos Algaba Marcos , Zamri bin Zainal Abidin

We present the results of unfiltered and UBVR_cI_c band CCD photometry fast nova V2467Cyg. Our analysis of the data gives two distinct frequencies corresponding to periods of ~3.8h and ~35 min. The observed light curve of V2467 Cyg is…

Solar and Stellar Astrophysics · Physics 2010-04-07 E. Swierczynski , M. Mikolajewski , T. Tomov , E. Ragan , C. Galan , A. Karska , P. Wychudzki , M. Wiecek , M. Cikala , M. Lewandowski