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Related papers: On Pulsar Distance Measurements and their Uncertai…

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The binary pulsar J2222-0137 is an enigmatic system containing a partially recycled millisecond pulsar and a companion of unknown nature. Whilst the low eccentricity of the system favors a white dwarf companion, an unusual double neutron…

Solar and Stellar Astrophysics · Physics 2015-06-16 A. T. Deller , J. Boyles , D. R. Lorimer , V. M. Kaspi , M. A. McLaughlin , S. Ransom , I. H. Stairs , K. Stovall

We investigate properties of Galactic microlensing events in which a stellar object is lensed by a neutron star. For an all-sky photometric microlensing survey, we determine the number of lensing events caused by $\sim10^{5}$…

Astrophysics of Galaxies · Physics 2015-07-03 Shi Dai , Martin C. Smith , Mengxiang Lin , Youling Yue , George Hobbs , Renxin Xu

The statistical properties of galaxy distance estimators are studied and a rigorous framework is developed for identifying and removing the effects of Malmquist bias due to obsevational selection. The prescription of Schechter (1980) for…

Astrophysics · Physics 2009-10-22 Martin A. Hendry , John F. L. Simmons

In this talk I review some of the key questions that weak lensing observations of clusters can potentially answer, and sketch the progress that has been made to date in extracting quantitative estimates of masses and density profiles. A…

Astrophysics · Physics 2007-05-23 Nick Kaiser

Strong gravitational lensing offers constraints on the Hubble constant that are independent of other methods. However, those constraints are subject to uncertainties in lens models. Previous studies suggest that using an elliptical power…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-02 Dilys Ruan , Charles R. Keeton

Very long baseline interferometry (VLBI) provides the resolution needed to make precision measurements of a pulsar's parallax and proper motion. In making these measurements, the astronomer is faced with difficult calibration problems and a…

Astrophysics · Physics 2007-05-23 Walter Brisken

The degradation of spatial resolution in star-forming regions observed at large distances ($d\gtrsim1$ kpc) with Herschel,can lead to estimates of the physical parameters of the detected compact sources (clumps) which do not necessarily…

Obtaining pulsar parallaxes via relative astrometry (also known as differential astrometry) yields distances and transverse velocities that can be used to probe properties of the pulsar population and the interstellar medium. Large programs…

Solar and Stellar Astrophysics · Physics 2011-10-13 A. T. Deller , W. F. Brisken , S. Chatterjee , J. M. Cordes , W. M. Goss , G. H. Janssen , Y. Y. Kovalev , T. J. W. Lazio , L. Petrov , B. W. Stappers

Globular clusters are among the first objects used to establish the distance scale of the Universe. In the 1970-ies it has been recognized that the differential magnitude distribution of old globular clusters is very similar in different…

Cosmology and Nongalactic Astrophysics · Physics 2012-01-20 M. Rejkuba

A forefront area of research concerns the exploration of the properties of hadronic matter under extreme conditions of temperature and density, and the determination of the equation of state--the relation between pressure, temperature and…

Astrophysics · Physics 2008-11-26 F. Weber , R. Negreiros , P. Rosenfield , M. Stejner

Pulsar radio emission undergoes dispersion due to the presence of free electrons in the interstellar medium (ISM). The dispersive delay in the arrival time of pulsar signal changes over time due to the varying ISM electron column density…

Distance measures on a coherent scale around the sky are required to address the outstanding cosmological problems of the Hubble Constant and of departures from the mean cosmic flow. The correlation between galaxy luminosities and rotation…

The goal of the present paper is to assess the usefulness of quasars as cosmological distance indicators. We calibrate, in a model-independent way, the non-linear relation between X-ray and UV emission to derive quasar luminosity distances.…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-12 Ariadna Montiel , Sofia Samario-Nava , Juan Carlos Hidalgo , Jose Ignacio Cabrera

We have detected a strong deflection of radio waves from the pulsar PSR B0834+06 in scintillation observations. Interference between the undeflected pulsar image and deflected subimages allows single dish interferometry of the interstellar…

We test two different methods of using near-infrared extinction to estimate distances to dark clouds in the first quadrant of the Galaxy using large near infrared (2MASS and UKIDSS) surveys. VLBI parallax measurements of masers around…

Astrophysics of Galaxies · Physics 2015-06-04 Jonathan B. Foster , Joseph J. Stead , Robert A. Benjamin , Melvin G. Hoare , James M. Jackson

In order to examine the pulse profile from a pulsar, we derive the formula for describing the flux from antipodal hot spots with any static, spherically symmetric spacetime. We find that the pulse profiles are almost independent of the…

High Energy Astrophysical Phenomena · Physics 2017-11-17 Hajime Sotani , Umpei Miyamoto

Hubble Space Telescope (HST) Fine Guidance Sensor (FGS) trigonometric parallax observations were obtained to directly determine distances to five nearby M-dwarf / M-dwarf eclipsing binary systems. These systems are intrinsically interesting…

Emission from blazar jets in the ultraviolet, optical, and infrared is polarized. If these low-energy photons were inverse-Compton scattered, the upscattered high-energy photons retain a fraction of the polarization. Current and future…

High Energy Astrophysical Phenomena · Physics 2015-02-03 Nachiketa Chakraborty , Vasiliki Pavlidou , Brian Fields

This article describes a parallax experiment performed by undergraduate physics students at Queensland University of Technology. The experiment is analogous to the parallax method used in astronomy to measure distances to the local stars.…

Physics Education · Physics 2015-10-05 Stephen Hughes , Sean Powell , Joshua Carroll , Michael Cowley

We combine Spitzer and ground-based observations to measure the microlens parallax vector ${\mathbf \pi}_{\rm E}$, and so the mass and distance of OGLE-2014-BLG-0124L, making it the first microlensing planetary system with a space-based…