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1.
All the confirmed Soft Gamma-ray Repeaters have been observed with the EPIC instrument on the XMM–Newton satellite. We review
the results obtained in these observations, providing the most accurate spectra on the persistent X-ray emission in the 1–10
keV range for these objects, and discuss them in the context of the magnetar interpretation.
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2.
Thanks to INTEGRAL’s long exposures of the Galactic Plane, the two brightest Soft Gamma-Ray Repeaters, SGR 1806-20 and SGR
1900+14, have been monitored and studied in detail for the first time at hard-X/soft gamma rays.
This has produced a wealth of new scientific results, which we will review here. Since SGR 1806-20 was particularly active
during the last two years, more than 300 short bursts have been observed with INTEGRAL and their characteristics have been
studied with unprecedented sensitivity in the 15–200 keV range. A hardness-intensity anticorrelation within the bursts has
been discovered and the overall Number-Intensity distribution of the bursts has been determined. In addition, a particularly
active state, during which 100 bursts were emitted in 10 minutes, has been observed on October 5 2004, indicating that the
source activity was rapidly increasing. This eventually led to the Giant Flare of December 27th 2004, for which a possible
soft gamma-ray (>80 keV) early afterglow has been detected.
The deep observations allowed us to discover the persistent emission in hard X-rays (20–150 keV) from 1806-20 and 1900+14,
the latter being in a quiescent state, and to directly compare the spectral characteristics of all Magnetars (two SGRs and
three Anomalous X-ray Pulsars) detected with INTEGRAL.
D.G. acknowledges the French Space Agency (CNES) for financial support. Based on observations with INTEGRAL, an ESA project
with instruments and the science data centre funded by ESA member states (especially the PI countries: Denmark, France, Germany,
Italy, Switzerland, Spain), Czech Republic and Poland, and with the participation of Russia and the USA. ISGRI has been realized
and maintained in flight by CEA-Saclay/DAPNIA with the support of CNES. K.H. is grateful for support under NASA’s INTEGRAL
U.S. Guest Investigator program, Grants NAG5-13738 and NNG05GG35G. 相似文献
3.
本实验以坛紫菜自由丝状体为材料,研究不同培养方式(静置、摇床、通气)和换水频率(5d、7d、10d、20d)对丝状体生长及藻胆蛋白(PE、PC)含量变化的影响。研究结果表明:坛紫菜自由丝状体在摇床培养条件下生长较好,特定生长速率可达10.832 7%~10.891 5%;摇床培养下的丝状体PE含量相对静置培养的较高一些,通气培养的相对较低,最高为36.816 8mg/g;静置条件下培养的丝状体PC含量最高,摇床培养次之,通气培养最低,最低为1.082 4mg/g。相同培养方式下,换水频率对丝状体特定生长速率影响不大;除通气培养外,换水频率20d其PE、PC含量较高。方差分析结果表明:实验范围内的培养方式及换水频率对丝状体特定生长速率大小、PE和PC含量不存在交互作用。本文实验结果对坛紫菜自由丝状体产业化应用于食品加工、色素提取等产业提供了实验理论和依据。 相似文献
4.
I. F. Malov 《Astronomy Letters》2008,34(10):699-703
At present, it is widely believed that anomalous X-ray pulsars (AXPs), soft gamma-ray repeaters (SGRs), rotational radio transients (RRATs), compact central objects (CCOs) in supernova remnants, and X-ray dim isolated neutron stars (XDINSs) belong to different classes of anomalous objects in which the central bodies are isolated neutron stars. Previously, we have shown that AXPs and SGRs can be described in terms of the drift model for parameters of the central neutron star typical of radio pulsars (rotation periods P ~ 0.1–1 s and surface magnetic fields B ~ 1011–1013 G). Here, we show that some of the peculiarities of the sources under consideration can be explained by their geometry (in particular, by the angle β between the rotation axis and the magnetic moment). If β ? 10° (an aligned rotator), the drift waves in the outer layers of the neutron star magnetosphere can account for the observed periodicity in the radiation. For large β (a nearly orthogonal rotator), the observed modulation of the radiation and its short bursts can be explained by mass accretion from the ambient medium (e.g., a relic disk). 相似文献
5.
Alaa I. Ibrahim Hisham Anwer Mohamed H. Soliman Nicholas Mackie-Jones Kalvir S. Dhuga William C. Parke Jean H. Swank Tilan Ukwatta M. T. Hussein T. El-Sherbini 《Astrophysics and Space Science》2007,308(1-4):535-539
A 6.4 keV emission line was discovered in an unusual burst from the soft gamma repeater SGR 1900+14 with the Rossi X-ray Timing
Explorer (RXTE). The line was detected in part of a complex multipeak precursor that preceded the unusual burst of 1998 August
29, i.e. two days after the giant flare of August 27 from the source. The origin of the line was not firmly identified and
two possible interpretations were equally plausible including (a) Kα fluorescence from a small iron rich material that was ejected to the magnetosphere during the August 27 flare, and (b) proton
or α-particle cyclotron resonance. If the iron scenario was correct, we expect to find evidence for the line during the intervening
interval between the flare and the August 29 burst, i.e. on August 28. Here we present the results of the August 28 burst
observation, taken with RXTE. We detect a total of seven bursts whose individual and joint spectra do not show evidence for
spectral lines. We also investigated a sample of nine bursts before and after the August 29 burst (from 1998 June to December)
that do not reveal evidence for a spectral line near 6.4 keV or elsewhere. These results disfavor the iron scenario and make
the proton/α-particle cyclotron resonance interpretation more plausible. The appearance of the emission line in part of a complex burst
and its absence from the studied sample indicate that the line is likely due to a transient phenomenon that may depend on
the burst morphology, energetics and the properties of the emission region.
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6.
7.
We report here results from a study of X-ray bursts from 3 magnetar candidates (SGR 1806-20, SGR 1900+14 and AXP 1E 2259+586).
We have searched for a pulse phase dependence of the X-ray burst rate from these sources. X-ray light curves were obtained
with the Proportional Counter Array on-board the Rossi X-ray Timing Explorer during the periods of intense burst activity
in these sources. On detailed analysis of the three sources, we found a very significant burst rate for all pulsar phases.
However, some locations appear to produce bursts slightly more often, rendering the non-isotropic distribution. Only in the
case of SGR 1900+14, there is a clear pulse phase dependence of burst rate. 相似文献
8.
9.
贝尔凹陷断层侧向封闭能力定量研究 总被引:1,自引:0,他引:1
通过建立断裂带页岩断层泥比率(SGR)与断裂侧向所能封闭油柱高度函数关系式的方法,开展了断层侧向封闭能力定量评价方法的探讨,并对贝尔凹陷断层侧向封闭能力进行定量研究。结果表明:断裂带SGR与其所能封闭油柱高度具有指数关系,断层侧向封闭能力取决于断面SGR的三维空间分布。利用贝301区块油藏数据所建立的断裂侧向封闭失效包络线函数式预测了呼和16圈闭油水界面为-1 025m,并得到钻井证实。贝尔凹陷断层侧向封闭能力总体上表现为:垂向上南屯组以上断层封闭性较强,平面上贝西南断层封闭性较强。 相似文献
10.
C. Childs Ø. Sylta S. Moriya N. Morewood T. Manzocchi J.J. Walsh D. Hermanssen 《Marine and Petroleum Geology》2009
It is widely acknowledged that fault rock capillary properties are important in controlling the distribution of hydrocarbons in sedimentary basins, and methods exist for predicting the capillary seal capacity of prospect bounding faults. However, fault seal capacity is rarely incorporated into models of hydrocarbon migration. This paper presents the results of migration modelling of the Oseberg Syd area of the Viking Graben incorporating fault rock capillary properties. Seal capacity is calculated in the model as a function of Shale Gouge Ratio (SGR), i.e. the percentage shale in the sequence moved past a point on a fault. Over 3000 model realisations were run for different SGR to fault seal capacity relationships and the calculated hydrocarbon distributions were compared with known distributions. Realisations were ranked according to the closeness of fit between model and actual oil–water contacts for 7 traps. The best-fit to all 7 traps was provided by realisations with significant seal capacity at SGR values greater than ca. 0.2; a value which is in agreement with an independently derived fault-by-fault calibration between SGR and seal capacity. The level of fill calculated for an individual trap is extremely sensitive to minor changes in the seal capacity relationship because it is controlled not only by the seal capacities of the faults that bound the trap, but also by the pattern of fill–spill of upstream traps. This sensitivity to minor changes in seal capacity introduces large uncertainties when fault seal capacity relationships are used in a predictive mode and emphasises the requirement for migration modelling in fault seal prospect evaluation. 相似文献