搜索结果: 1-15 共查到“知识库 Ｘ射线天文学”相关记录107条 . 查询时间(1.421 秒)
近日，中国科学院近代物理研究所的科研人员及合作者通过实验首次得到了X射线暴温度区间的22Mg(α,p)25Al天体反应率，为深入理解X射线暴的光变曲线和X射线双星系统的天体物理环境，提供了重要的实验数据，相关成果于10月19日发表在Physics Review Letters上。
肺纯磨玻璃结节CT定量分析研究进展
肺腺癌 计算机X射线断层术 定量分析 病理
2020/8/26
随着多层螺旋CT的不断发展及临床肺癌CT筛查的逐渐普及，肺内磨玻璃密度结节的检出率显著增加，且大部分被证实与早期肺腺癌密切相关，因此肺内磨玻璃密度结节不断受到国内外学者关注。磨玻璃密度结节的浸润程度与是否手术或手术方法的选择密切相关。因此，对于术前肺内磨玻璃结节CT表现特征与不同病理分型的对照研究有重要的临床价值。全文就目前有关肺纯磨玻璃结节CT定量分析与病理对照研究情况予以综述。
Characterizing Distant Galaxies: Spectral Energy Distribution Analysis of X-ray Selected Star Forming Galaxies
galaxies - fundamental parameters Galaxies - high redshift Galaxies - submillimeter methods - statistical
2014/12/9
Comprehensive and robust analysis of galaxies found throughout cosmic time provides the means to probe the underlying characteristics of our Universe. Coupling observations and theory, spectral energy...
非稳态吸积主导X射线双星从硬态到软态的态跃迁
吸积盘 黑洞 X射线双星
2012/9/12
最近几年一些新的研究发现，X射线双星从硬态到软态的态跃迁光度和随后的软态峰值光度成正相关，而且还发现了从硬态到软态的态跃迁光度和上升时期的光度增加率成正相关，这两个经验关系表明最亮的硬态和从硬态到软态的态跃迁主要是由吸积率的变化率所表征的非稳态吸积过程所主导的。对GX 339-4的研究表明，硬X射线峰值光度由爆发前吸积盘所积累的质量决定，而且低质量X射线双星暂现源的爆发峰值光度和轨道周期的正相关关...
ROSAT巡天X射线选活动星系核的光学认证
活动星系核 X 射线 光学证认
2012/9/12
获得完备的样本一直是类星体统计分析工作中至关重要的第一步。类星体巡天选择候选体的方法主要有射电波段筛选、色指数筛选、无缝光谱筛选、X 射线波段筛选、对红外源或变源进行筛选和零自行的方法。单独运用任一方法都有选择效应，采用多波段方法可以极大地提高样本的完备性。阐述了使用多波段方法选择活动星系核样本的研究现状，提出多波段类星体巡天方法和选源判据，给出 ROSAT 巡天中 F.1002，F.Coma，F...
本论文基于X射线空间卫星的多波段监测数据,研究明亮的低质量X射线双星的X射线能谱的演化和态跃迁过程,暂现源在爆发过程中的一些性质以及不同波段的光度的演化和相关关系。暂现源的爆发所涉及的光度范围很大,这对于研究吸积物理具有不可比拟的重要性,可以研究不同的吸积率下的吸积状态以及随着吸积率的演化过程和因果关系。通过这些研究增进我们对吸积物理的理解,尤其是暂现源爆发过程中X射线能谱演化的驱动机制,喷流的性...
Extreme Warm Absorber variability in the Seyfert Galaxy Mrk 704
Galaxies: active – X-rays: galaxies – X-rays: individual: Mrk 704
2011/9/28
In about half of Seyfert galaxies, the X-ray emission is absorbed by an optically thin, ionized medium, the so-called "Warm Absorber", whose origin and location is still a matter of debate. The aims o...
Intrinsic disc emission and the Soft X-ray Excess in AGN
X-rays: accretion discs black hole physics
2011/10/18
Narrow Line Seyfert 1 (NLS1) galaxies have low mass black holes and mass accretion rates close to (or exceeding) Eddington, so a standard blackbody accretion disc should peak in the EUV. However, the ...
Average Heating Rate of Hot Atmospheres in Distant Clusters by Radio AGN: Evidence for Continuous AGN Heating
Average Heating Atmospheres Distant Clusters Evidence Continuous Heating
2011/10/9
We examine atmospheric heating by radio active galactic nuclei (AGN) in distant X-ray clusters by cross correlating clusters selected from the 400 Square Degree (400SD) X-ray Cluster survey with radio...
Evidence for crust cooling in the transiently accreting 11-Hz X-ray pulsar in the globular cluster Terzan 5
globular clusters: individual (Terzan 5) - X-rays: binaries - stars: neutron -pulsars: individual (CXOGClb J174804.8–244648, IGR J17480–2446)
2011/10/17
The temporal heating and subsequent cooling of the crusts of transiently accreting neutron stars carries unique information about their structure and a variety of nuclear reaction processes. We report...
Emission geometry, radiation pattern, and magnetic topology of the magnetar XTE J1810-197 in its quiescent state
pulsars: general – stars: neutron – X-rays: individual: XTE J1810− 197
2011/10/17
The return to the quiescent state of the Anomalous X-ray pulsar XTE J1810-197 following its 2003 outburst represents a unique opportunity to probe the surface emission properties of a magnetar. The qu...
GRIPS and the Perspective of Next-generation Gamma-ray Surveys
GRIPS Perspective Next-generation Gamma-ray Surveys
2011/10/19
GRIPS is one example of next generation telescopes proposed for astronomy the energy range between hard X-ray mirror instruments such as NuStar and the Fermi telescope. The Compton telescope principle...
Improvements in calibration of GSO scintillators in the Suzaku Hard X-ray Detector
instrumentation: detectors — X-rays: general — X-rays: individual
2011/10/19
Improvements of in-orbit calibration of GSO scintillators in the Hard X-ray Detector on board Suzaku are reported. To resolve an apparent change of the energy scale of GSO which appeared across the la...
MAXI GSC monitoring of the Crab nebula and pulsar during the GeV gamma-ray flare in September 2010
stars: neutron — stars: pulsars: individual (Crab) — X-rays: indi- vidual
2011/10/12
We report on the MAXI GSC X-ray monitoring of the Crab nebula and pulsar during the GeV gamma-ray flare for the period of 2010 September 18-24 (MJD 55457-55463) detected by AGILE and Fermi-LAT. There ...
In 2004, SGR 1806-20 underwent a period of intense and long-lasting burst activity that included the giant flare of 27 December 2004 -- the most intense extra-solar transient event ever detected at Ea...