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111.
What is the origin of the soft excess in active galactic nuclei? 总被引:1,自引:0,他引:1
Magorzata A. Sobolewska Chris Done 《Monthly notices of the Royal Astronomical Society》2007,374(1):150-158
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Mark Cropper Silvia Zane Roberto Turolla Luca Zampieri Matteo Chieregato Jeremy Drake Aldo Treves 《Astrophysics and Space Science》2007,308(1-4):161-166
We report XMM-Newton observations of the isolated neutron star RBS1774 and confirm its membership as an XDINS. The X-ray spectrum is best fit
with an absorbed blackbody with temperature kT=101 eV and absorption edge at 0.7 keV. No power law component is required. An absorption feature in the RGS data at 0.4 keV
is not evident in the EPIC data, but it is not possible to resolve this inconsistency. The star is not seen in the UV OM data
to m
AB
∼21. There is a sinusoidal variation in the X-ray flux at a period of 9.437 s with an amplitude of 4%. The age as determined
from cooling and magnetic field decay arguments is 105–106 yr for a neutron star mass of 1.35–1.5 M⊙.
相似文献
115.
??Bernese??????ж??ο???????????????????????t??????λ??????λ??,??????????13??????????2013\|07\|23??29?????????е??????????GPS??λ????????????????????????λ???????cm??????????λ???????mm?????? 相似文献
116.
新型GPS探空仪与业务GTS1 2探空仪对比分析 总被引:1,自引:0,他引:1
2012年8月,中国气象局气象探测中心在广东阳江开展自动探空系统新型GPS探空仪比对试验,对比分析其技术改进后的准确性,试验结果表明:温度测量性明显优于GTS1 2型探空仪。湿度测量结果与RS92型探空仪一致性较好,系统误差在15%RH内,标准偏差在12%RH内。气压系统误差全量程在±10 hPa内,标准偏差在08 hPa内。位势高度系统误差在±20 gpm以内,标准偏差在70 gpm内。GPS定位测风性能优于GTS1 2型探空仪配合L波段二次测风雷达测风性能结果。 相似文献
117.
We look for high‐amplitude variable young stars in the open clusters and associations of the Orion Belt. We use public data from the ASAS‐3 Photometric V ‐band Catalogue of the All Sky Automated Survey, infrared photometry from the 2MASS and IRAS catalogues, proper motions, and the Aladin sky atlas to obtain a list of the most variable stars in a survey area of side 5° centred on the bright star Alnilam (ε Ori) in the centre of the Orion Belt. We identify 32 highly variable stars, of which 16 had not been reported to vary before. They are mostly variable young stars and candidates (16) and background giants (8), but there are also field cataclysmic variables, contact binaries, and eclipsing binary candidates. Of the young stars, which typically are active Herbig Ae/Be and T Tauri stars with Hα emission and infrared flux excess, we discover four new variables and confirm the variability status of another two. Some of them belong to the well known σ Orionis cluster. Besides, six of the eight giants are new variables, and three are new periodic variables (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
118.
M. Henze W. Pietsch F. Haberl G. Sala M. Hernanz D. Hatzidimitriou A. Rau D.H. Hartmann J. Greiner M. Orio H. Stiele M.J. Freyberg 《Astronomische Nachrichten》2010,331(2):193-196
Classical novae (CNe) have recently been reported to represent the major class of supersoft X‐ray sources (SSSs) in the central area of our neighbouring galaxy M 31. This paper presents a review of results from recent X‐ray observations of M 31 with XMM‐Newton and Chandra. We carried out a dedicated optical and X‐ray monitoring program of CNe and SSSs in the central area ofM 31. We discovered the first SSSs in M 31 globular clusters (GCs) and their connection to the very first discovered CN in a M 31 GC. This result may have an impact on the CN rate in GCs. Furthermore, in our optical and X‐ray monitoring data we discovered the CN M3 1N 2007‐11a, which shows a very short SSS phase of 29–52 days. Short SSS states (durations ≤ 100 days) of CNe indicate massive white dwarfs (WDs) that are candidate progenitors of supernovae type Ia. In the case of M31N 2007‐11a, the optical and X‐ray light curves suggest a binary containing a WD with MWD > 1.0 M⊙. Finally, we present the discovery of the SSS counterpart of the CN M31N 2006‐04a. The X‐ray light curve of M31N 2006‐04a shows short‐time variability, which might indicate an orbital period of about 2 hours (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
119.
Effect of Decadal Changes in Air-Sea Interaction on the Climate Mean State over the Tropical Pacific 下载免费PDF全文
Collaboration of interannual variabilities and the climate mean state determines the type of E1 Nifio. Recent studies highlight the impact of a La Nifia-like mean state change, which acts to suppress the convection and low-level convergence over the central Pacific, on the predominance of central Pacific (CP) E1 Nifio in the most recent decade. However, how interannual variabilities affect the climate mean state has been less thoroughly investigated. Using a linear shallow-water model, the ef- fect of decadal changes of air-sea interaction on the two types of El Nifio and the climate mean state over the tropical Pacific is examined. It is demonstrated that the predominance of the eastem Pacific (EP) and CP E1 Nino is dominated mainly by relationships between anomalous wind stresses and sea surface temperature (SST). Furthermore, changes between air-sea interactions from 1980-98 to 1999-2011 prompted the generation of the La Ninalike pattern, which is similar to the background change in the most recent decade. 相似文献
120.