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Southern Pacific (SP) 4151
No full textA photograph print showing the Southern Pacific (SP) 4151, 4-8-8-2, cab forward, Sacramento, CA
赛弗特1型星系NGC 4151的光变研究
No full text赛弗特星系NGC 4151是一个离我们最近（当哈勃常数取75 km s-1Mpc-1时，红移为0.00332，距离为13.2 Mpc）和最亮的赛弗特1型星系之一。NGC 4151的寄主星系是一个典型的旋涡星系SABab(Perez Garcia 等人 1998)。由于它的明亮性和光变特性使得它成为目前整个电磁波段研究最多和最好的天体之一，可以用来测试不同的理论模型。
本文综述了活动星系核（active galaxy nucleus, AGN），以及NGC 4151的研究现状，同时阐述了天文上CCD的观测过程以及NGC 4151观测资料的处理中所用到参数的选取。测光观测对于得到光变曲线以及研究不同时标的光变具有重要的意义。CCD测光，可以直接得到天体的光变曲线、视星等、光变时标、色指数等重要的物理参数。对这些测光结果的分析，可以对天体的物理特性、理论模型、动力学性质和演化过程进行深入的研究，因此CCD测光对天体物理学的发展具有重要的意义。
在使用IRAF数据处理软件对2003年5月2日的观测资料进行测光来获得光变曲线时，在三个波段同时发现了一个可能的微光变，并给出了引起微光变的几个可能的物理机制。如果微光变是由吸积盘上热斑运动引起的，则可以根据微光变的时标来估算其中央黑洞的质量。我们利用这种方法估算得到NGC 4151中央黑洞的质量。收集了NGC 4151在V波段从1968年到2003年的光电测光和CCD测光的历史光变资料以及B波段从1910年到2000年的历史光变资料。在获得历史光变资料后利用Jurkevich方法和DCF两种方法来求光变周期，这两种方法得到的周期基本上是吻合的。同时我们讨论了长周期光变的几种可能机制，最后求得了NGC 4151不同波段之间的色指数
Observing NGC 4151 with the Keck Interferometer
No full textObservations of the nucleus of NGC 4151 at 2.2 microns using the two 10-meter Keck telescopes as an interferometer show a marginally resolved source less than or equal to 0.1 pc in diameter. These observations are the first measurement of an extragalactic source with an optical/IR interferometer. These observations represent a ten-fold improvement in angular resolution when compared to previous near-infrared measurements of AGN and make it possible to test the subparsecscale, near-infrared emission models of NGC 4151
The complex soft X-ray spectrum of NGC 4151
No full textWe present a detailed analysis of the complex soft X‐ray spectrum of NGC 4151 measured by the RGS instruments on board XMM–Newton. The XMM–Newton RGS spectra demonstrate that the soft X‐ray emission is extremely rich in X‐ray emission lines and radiative recombination continua (RRC), with no clear evidence for any underlying continuum emission. Line emission and the associated RRC are clearly detected from hydrogen‐like and helium‐like ionization states of neon, oxygen, nitrogen and carbon. The measured lines are blueshifted with a velocity of ∼100–1000 km s−1, with respect to the systemic velocity of NGC 4151, approximately consistent with the outflow velocities of the absorption lines observed in the ultraviolet spectrum of NGC 4151 by Kriss et al. in the mid‐1990s, suggestive of an origin for the ultraviolet and soft X‐ray emission in the same material. Plasma diagnostics from the observed helium‐like triplets imply a range of electron temperatures of ∼(1–5) × 104 K and electron densities of between 108 and 1010 cm−3. The soft X‐ray spectrum of NGC 4151 is extremely similar to that of NGC 1068, in terms of both the atomic species present and the relative strengths of the observed emission lines and RRC (reported recently by Kinkhabwala et al.), suggesting that the soft X‐ray excesses observed in many type 2 Seyfert galaxies may be composed of similar emission features. Modelling the RGS spectra in terms of emission from photoionized and photoexcited gas in an ionization cone reproduces all of the hydrogen‐like and helium‐like emission features observed in the soft X‐ray spectrum of NGC 4151 in detail and confirms the correspondence between the soft X‐ray emission in NGC 4151 and 1068. NGC 4151 shows somewhat lower individual ionic column densities than those measured for NGC 1068, indicating that the material in the ionization cones of NGC 4151 may be somewhat more dense than the material in the ionization cones of NGC 1068
Block Card 4151 Birchall Road
No full textThis image was produced by the Auditor's Office in Lucas County, Ohio for tax assessment purposes. Associated dates are approximate. Descriptive terms related to this photograph include: Dwelling (Toledo, Ohio) | Bungalow Style | Craftsman Style | Homeville Subdivision (Toledo, Ohio) | Willys Park area (Toledo, Ohio) | West Toledo (Toledo, Ohio) | 4151 Birchall Road (Toledo, Ohio
Block Card 4151 McGregor Lane
No full textThis image was produced by the Auditor's Office in Lucas County, Ohio for tax assessment purposes. Associated dates are approximate. Descriptive terms related to this photograph include: garrison colonial | 4151 McGregor Lane (Toledo, Ohio) | Dwelling | Concord Woods Addition (Toledo, Ohio) | Trilby Area (Toledo, Ohio)
Block Card 4151 Pawnee Road
No full textThis image was produced by the Auditor's Office in Lucas County, Ohio for tax assessment purposes. Associated dates are approximate. Descriptive terms related to this photograph include: Ranch houses | 4151 Pawnee Road (Toledo, Ohio) | Dwelling | Fairgreen Addition (Toledo, Ohio) | Trilby Area (Toledo, Ohio)
Block Card 4151 Talwood Lane
No full textThis image was produced by the Auditor's Office in Lucas County, Ohio for tax assessment purposes. Associated dates are approximate. Descriptive terms related to this photograph include: Dwelling – Ohio – Toledo | Ranch Style | Plat of Talwood (Toledo, Ohio) | Westgate Area (Toledo, Ohio) | West Toledo (Toledo, Ohio) | 4151 Talwood Lane (Toledo, Ohio
Block Card 4151 Carthage Road
No full textThis image was produced by the Auditor's Office in Lucas County, Ohio for tax assessment purposes. Associated dates are approximate. Descriptive terms related to this photograph include: Dwelling (Toledo, Ohio) | side gabled | Craftsman Style | Homeville Subdivision (Toledo, Ohio) | Willys Park area (Toledo, Ohio) | West Toledo (Toledo, Ohio) | 4151 Carthage Road (Toledo, Ohio) | Folk House Styl
Block Card 4151 East Way
No full textThis image was produced by the Auditor's Office in Lucas County, Ohio for tax assessment purposes. Associated dates are approximate. Descriptive terms related to this photograph include: Dwelling (Toledo, Ohio) | Bungalow Style | Craftsman Style | Homeville Subdivision (Toledo, Ohio) | Willys Park area (Toledo, Ohio) | West Toledo (Toledo, Ohio) | 4151 East Way (Toledo, Ohio
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