中国科学院机构知识库网格系统: 检索

A compact symmetric radio source born at one-tenth the current age of the Universe 期刊论文 OAI收割
Monthly Notices of the Royal Astronomical Society, 2022, 卷号: 511, 期号: 3, 页码: 4572-4581
作者: An, Tao; Wang, Ailing; Zhang, Yingkang; Aditya, J. N. H. S.; Hong, Xiaoyu

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收藏 | 浏览/下载：25/0 | 提交时间：2023/06/19

instrumentation: high angular resolution methods: observational galaxies: individual: J1606+3124 galaxies: jets galaxies: nuclei active galactic nuclei all-sky survey steep-spectrum black-holes luminosity function evolution galaxies scale redshift catalog Astronomy & Astrophysics

Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign 期刊论文 OAI收割
The Astrophysical Journal Letters, 2021, 卷号: 911, 期号: 1
作者:

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Active galactic nuclei Radio cores Low-luminosity active galactic nuclei High energy astrophysics Astrophysical black holes Accretion

Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign 期刊论文 OAI收割
The Astrophysical Journal Letters, 2021, 卷号: 911, 期号: 1
作者: Algaba,J. C.; Anczarski,J.; Asada,K.; Balokovi?,M.; Chandra,S.

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收藏 | 浏览/下载：106/0 | 提交时间：2021/12/06

Active galactic nuclei Radio cores Low-luminosity active galactic nuclei High energy astrophysics Astrophysical black holes Accretion

Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign 期刊论文 OAI收割
The Astrophysical Journal Letters, 2021, 卷号: 911, 期号: 1
作者: Algaba,J. C.; Anczarski,J.; Asada,K.; Balokovi?,M.; Chandra,S.

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收藏 | 浏览/下载：90/0 | 提交时间：2021/12/06

Active galactic nuclei Radio cores Low-luminosity active galactic nuclei High energy astrophysics Astrophysical black holes Accretion

Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign 期刊论文 OAI收割
The Astrophysical Journal, 2021, 卷号: 911, 页码: L11
作者: Algaba, J. C.; Anczarski, J.; Asada, K.; Baloković, M.; Chandra, S.

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收藏 | 浏览/下载：65/0 | 提交时间：2022/06/30

Active galactic nuclei Radio cores Low-luminosity active galactic nuclei High energy astrophysics Astrophysical black holes Accretion Astrophysics - High Energy Astrophysical Phenomena Astrophysics - Cosmology and Nongalactic Astrophysics Astrophysics - Astrophysics of Galaxies

The Hyperluminous, Dust-obscured Quasar W2246–0526 at z?=?4.6: Detection of Parsec-scale Radio Activity 期刊论文 OAI收割
The Astrophysical Journal Letters, 2020, 卷号: 905, 期号: 2
作者: Fan,Lulu; Chen,Wen; An,Tao; Xie,Fu-Guo; Han,Yunkun

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收藏 | 浏览/下载：132/0 | 提交时间：2021/01/25

High-redshift galaxies Quasars Radio continuum emission High-luminosity active galactic nuclei

SCUBA-2 Ultra Deep Imaging EAO Survey (Studies). III. Multiwavelength Properties, Luminosity Functions, and Preliminary Source Catalog of 450 μm Selected Galaxies 期刊论文 OAI收割
The Astrophysical Journal, 2020, 卷号: 889, 期号: 2
作者: Lim,Chen-Fatt; Wang,Wei-Hao; Smail,Ian; Scott,Douglas; Chen,Chian-Chou

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收藏 | 浏览/下载：154/0 | 提交时间：2020/03/19

High-redshift galaxies Galaxy evolution Luminosity function Submillimeter astronomy

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

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Astrophysics - High Energy Astrophysical Phenomena Abstract: Fast radio bursts (FRBs) are millisecond-duration radio transients of unknown physical origin observed at extragalactic distances^1-3. It has long been speculated that magnetars are the engine powering repeating bursts from FRB sources^4-13, 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 flare^18-21. 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.

The braking index of PSR B0540-69 and the associated pulsar wind nebula emission after spin-down rate transition 期刊论文 OAI收割
Monthly Notices of the Royal Astronomical Society, 2020, 卷号: 494, 页码: 1865-1870
作者: HXMT

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stars: magnetic field stars: neutron pulsars: general Astrophysics - High Energy Astrophysical Phenomena Abstract: In 2011 December, PSR B054-69 experienced a spin-down rate transition (SRT), after which the spin-down power of the pulsar increased by $\sim 36{{\ \rm per\ cent}}$. About 1000 d after the SRT, the X-ray luminosity of the associated pulsar wind nebula (PWN) was found to brighten by $32\pm 8{{\ \rm per\ cent}}$. After the SRT, the braking index n of PSR B0540-69 changes from n = 2.12 to 0.03 and then keeps this value for about five years before rising to n = 0.9 in the following years. We find that most of the current models have difficulties in explaining the measured braking index. One exceptive model of the braking index evolution is the increasing dipole magnetic field of PSR B0540-69. We suggest that the field increase may result from some instabilities within the pulsar core that enhance the poloidal component at the price of toroidal component of the magnetic field. The increasing dipole magnetic field will result in the X-ray brightening of the PWN. We fit the PWN X-ray light curve by two models: one assumes a constant magnetic field within the PWN during the brightening and the other assumes an enhanced magnetic field proportional to the energy density of the PWN. It appears that the two models fit the data well, though the later model seems to fit the data a bit better. This provides marginal observational evidence that magnetic field in the PWN is generated by the termination shock. Future high-quality and high-cadence data are required to draw a solid conclusion.

Insight-HXMT observations of Swift J0243.6+6124: the evolution of RMS pulse fractions at super-Eddington luminosity 期刊论文 OAI收割
Monthly Notices of the Royal Astronomical Society, 2020, 卷号: 497, 页码: 5498-5506
作者: HXMT

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stars: neutron pulsars: individual: Swift J0243.6+6124 X-rays: binaries Astrophysics - High Energy Astrophysical Phenomena Abstract: Based on Insight-HXMT data, we report on the pulse fraction evolution during the 2017-2018 outburst of the newly discovered first Galactic ultraluminous X-ray (ULX) source Swift J0243.6+6124. The pulse fractions of 19 observation pairs selected in the rising and fading phases with similar luminosity are investigated. The results show a general trend of the pulse fraction increasing with luminosity and energy at supercritical luminosity. However, the relative strength of the pulsation between each pair evolves strongly with luminosity. The pulse fraction in the rising phase is larger at luminosity below 7.71 × 10³⁸ erg s^-1, but smaller at above. A transition luminosity is found to be energy independent. Such a phenomenon is first confirmed by Insight-HXMT observations and we speculate that it may have relation with the radiation-pressure-dominated accretion disc.