نتایج جستجو برای: astrometry
تعداد نتایج: 1642 فیلتر نتایج به سال:
We report on VLBA astrometry and CXO imaging of PSR J0538+2817 in the supernova remnant S147. We measure a parallax distance of 1.47 −0.27 kpc along with a high-precision proper motion, giving a transverse velocity V⊥ = 400 −73 km s . A small extended wind nebula is detected around the pulsar; the symmetry axis of this structure suggests that the spin axis lies 12 ± 4 from the velocity vector (...
The VLA-COSMOS Large Project is described and its scientific objective is discussed. We present a catalog of 3600 radio sources found in the 2 deg COSMOS field at 1.4 GHz. The observations in the VLA A and C configuration resulted in a resolution of 1:500 ; 1:400 and a mean rms noise of 10.5 (15) Jy beam 1 in the central 1 (2) deg. Eighty radio sources are clearly extended consisting of multipl...
We report on a substellar-companion search utilizing interferometric fringe-tracking astrometry acquired with Fine Guidance Sensor 3 on the Hubble Space Telescope. Our targets were Proxima Centauri and BarnardÏs star. We obtain absolute parallax values of for Proxima nabs\ 0A.7687^ 0A.0003 Cen and for BarnardÏs star. Once low-amplitude instrumental systematic errors nabs\ 0A.5454^ 0A.0003 are i...
On 18 November 1993, we observed the QSO 1150+812 and the BL Lac object 1803+784, nearly 15 apart on the sky, with a VLBI array, simultaneously recording at 8.4 and 2.3 GHz. Using difference astrometry techniques, we determined the coordinates of 1803+784 relative to those of 1150+812 to be ∆α = 6 7 33. 18469± 0. 00020 ∆δ = −2 30′ 25. 13557± 0. 00075 These standard errors contain estimated cont...
The distance to the Large Magellanic Cloud (LMC) can be directly determined by measuring three of its properties, its radial-velocity field, its mean proper motion, and the position angle φph of its photometric line of nodes. Statistical errors of ∼ 2% are feasible based on proper motions obtained with any of several proposed astrometry satellites, the first possibility being the Full-Sky Astro...
Aims. Accurate distances to evolved stars with high mass loss rates are needed for studies of many of their fundamental properties. However, as these stars are heavily obscured and variable, optical and infrared astrometry is unable to provide enough accuracy. Methods. Astrometry using masers in the circumstellar envelopes can be used to overcome this problem. We have observed the OH masers of ...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید