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浏览/检索结果: 共134条，第1-10条 帮助

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Analysis of signal-to-noise ratio of spatial heterodyne spectroscopy 期刊论文  OAI收割
MEASUREMENT, 2024, 卷号: 237
作者:  Wang, Qiansheng;  Luo, Haiyan;  Li, Zhiwei;  Ding, Yi;  Xiong, Wei
  |  收藏  |  浏览/下载：8/0  |  提交时间：2024/11/22
Ultra-wide Bandwidth Observations of 19 Pulsars with Parkes Telescope 期刊论文  OAI收割
Research in Astronomy and Astrophysics, 2022, 卷号: 22, 期号: 8, 页码: 85001
作者:  Zhou, Zu-Rong;  Wang, Jing-Bo;  Wang, Na;  Hobbs, George;  Wang, Shuang-Qiang
  |  收藏  |  浏览/下载：18/0  |  提交时间：2023/06/19
Precise measurements of thermionic emission behaviors for hot gas-phase C-60 and C-70 molecules 期刊论文  OAI收割
INTERNATIONAL JOURNAL OF MASS SPECTROMETRY, 2021, 卷号: 462, 页码: 5
作者:  Zhou, Wenchang;  Qian, Dongbin;  Yang, Jie;  Ma, Xinwen
  |  收藏  |  浏览/下载：26/0  |  提交时间：2021/12/10
Imaging and Spectral Study on the Null Point of a Fan-spine Structure During a Solar Flare 期刊论文  OAI收割
The Astrophysical Journal, 2020, 卷号: 898, 期号: 2
作者:  Yang, Shuhong;  Zhang, Qingmin;  Xu Z(徐稚);  Zhang, Jun;  Zhong, Ze
  |  收藏  |  浏览/下载：30/0  |  提交时间：2020/08/24
Imaging and Spectral Study on the Null Point of a Fan-spine Structure During a Solar Flare 期刊论文  OAI收割
The Astrophysical Journal, 2020, 卷号: 898, 期号: 2
作者:  Yang,Shuhong;  Zhang,Qingmin;  Xu,Zhi;  Zhang,Jun;  Zhong,Ze
  |  收藏  |  浏览/下载：29/0  |  提交时间：2021/12/06
Influence of metals and metalloids on the composition and fluorescence quenching of the extracellular polymeric substances produced by the polymorphic fungusAureobasidium pullulans 期刊论文  OAI收割
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY, 2020, 页码: 10
作者:  Song, Wenjuan;  Yang, Yuyi;  Liang, Xinjin;  Liu, Feixue;  Gadd, Geoffrey Michael
  |  收藏  |  浏览/下载：30/0  |  提交时间：2020/10/04
Influence of metals and metalloids on the composition and fluorescence quenching of the extracellular polymeric substances produced by the polymorphic fungusAureobasidium pullulans 期刊论文  OAI收割
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY, 2020, 页码: 10
作者:  Song, Wenjuan;  Yang, Yuyi;  Liang, Xinjin;  Liu, Feixue;  Gadd, Geoffrey Michael
  |  收藏  |  浏览/下载：24/0  |  提交时间：2020/10/04
Low temperature-boosted high efficiency photo-induced charge transfer for remarkable SERS activity of ZnO nanosheets 期刊论文  OAI收割
CHEMICAL SCIENCE, 2020, 卷号: 11, 期号: 35, 页码: 9414-9420
作者:  Lin, Jie;  Yu, Jian;  Akakuru, Ozioma Udochukwu;  Wang, Xiaotian;  Yuan, Bo
  |  收藏  |  浏览/下载：43/0  |  提交时间：2020/12/16
No pulsed radio emission during a bursting phase of a Galactic magnetar 期刊论文  OAI收割
Nature, 2020, 卷号: 587, 页码: 63-65
作者:  HXMT
  |  收藏  |  浏览/下载：44/0  |  提交时间：2022/02/08
Astrophysics - High Energy Astrophysical Phenomena  Abstract: Fast radio bursts (FRBs) are millisecond-duration radio transients of unknown physical origin observed at extragalactic distances1-3. It has long been speculated that magnetars are the engine powering repeating bursts from FRB sources4-13, but no convincing evidence has been collected so far14. Recently, the Galactic magnetar SRG 1935+2154 entered an active phase by emitting intense soft íray bursts15. One FRB-like event with two peaks (FRB 200428) and a luminosity slightly lower than the faintest extragalactic FRBs was detected from the source, in association with a soft íray/hard-X-ray flare18-21. Here we report an eight-hour targeted radio observational campaign comprising four sessions and assisted by multi-wavelength (optical and hard-X-ray) data. During the third session, 29 soft-íray repeater (SGR) bursts were detected in íray energies. Throughout the observing period, we detected no single dispersed pulsed emission coincident with the arrivals of SGR bursts, but unfortunately we were not observing when the FRB was detected. The non-detection places a fluence upper limit that is eight orders of magnitude lower than the fluence of FRB 200428. Our results suggest that FRB-SGR burst associations are rare. FRBs may be highly relativistic and geometrically beamed, or FRB-like events associated with SGR bursts may have narrow spectra and characteristic frequencies outside the observed band. It is also possible that the physical conditions required to achieve coherent radiation in SGR bursts are difficult to satisfy, and that only under extreme conditions could an FRB be associated with an SGR burst.  
An underlying clock in the extreme flip-flop state transitions of the black hole transient Swift J1658.2-4242 期刊论文  OAI收割
Astronomy and Astrophysics, 2020, 卷号: 641, 页码: A101
作者:  HXMT
  |  收藏  |  浏览/下载：58/0  |  提交时间：2022/02/08
accretion  accretion disks  black hole physics  X-rays: binaries  time  Astrophysics - High Energy Astrophysical Phenomena  Abstract:
Aims: Flip-flops are top-hat-like X-ray flux variations, which have been observed in some transient accreting black hole binary systems, and feature simultaneous changes in the spectral hardness and the power density spectrum (PDS). They occur at a crucial time in the evolution of these systems, when the accretion disc emission starts to dominate over coronal emission. Flip-flops remain a poorly understood phenomenon, so we aim to thoroughly investigate them in a system featuring several such transitions.
Methods: Within the multitude of observations of Swift J1658.2-4242 during its outburst in early 2018, we detected 15 flip-flops, enabling a detailed analysis of their individual properties and the differences between them. We present observations by XMM-Newton, NuSTAR, Astrosat, Swift, Insight-HXMT, INTEGRAL, and ATCA. We analysed their light curves, searched for periodicities, computed their PDSs, and fitted their X-ray spectra, to investigate the source behaviour during flip-flop transitions and how the interval featuring flip-flops differs from the rest of the outburst.
Results: The flip-flops of Swift J1658.2-4242 are of an extreme variety, exhibiting flux differences of up to 77% within 100 s, which is much larger than what has been seen previously. We observed radical changes in the PDS simultaneous with the sharp flux variations, featuring transitions between the quasi-periodic oscillation types C and A, which have never been observed before. Changes in the PDS are delayed, but more rapid than changes in the light curve. Flip-flops occur in two intervals within the outburst, separated by about two weeks in which these phenomena were not seen. Transitions between the two flip-flop states occurred at random integer multiples of a fundamental period of 2.761 ks in the first interval and 2.61 ks in the second. Spectral analysis reveals the high and low flux flip-flop states to be very similar, but distinct from intervals lacking flip-flops. A change of the inner temperature of the accretion disc is responsible for most of the flux difference in the flip-flops. We also highlight the importance of correcting for the influence of the dust scattering halo on the X-ray spectra.