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Constraining the X-Ray-Infrared Spectral Index of Second-timescale Flares from SGR 1935+2154 with Palomar Gattini-IR 期刊论文 OAI收割
The Astrophysical Journal, 2020, 卷号: 901, 页码: L7
作者: HXMT

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收藏 | 浏览/下载：28/0 | 提交时间：2022/02/08

Radio transient sources Magnetars Soft gamma-ray repeaters 2008 992 1471 Astrophysics - High Energy Astrophysical Phenomena Astrophysics - Instrumentation and Methods for Astrophysics Abstract: The Galactic magnetar SGR 1935+2154 has been reported to produce the first example of a bright millisecond-duration radio burst (FRB 200428) similar to the cosmological population of fast radio bursts (FRBs). The detection of a coincident bright X-ray burst represents the first observed multiwavelength counterpart of an FRB. However, the search for similar emission at optical wavelengths has been hampered by the high inferred extinction on the line of sight. Here, we present results from the first search for second-timescale emission from the source at near-infrared (NIR) wavelengths using the Palomar Gattini-IR observing system in the J band, enabled by a novel detector readout mode that allows short exposure times of ?0.84 s with 99.9% observing efficiency. With a total observing time of ?12 hr (?47,728 images) during its 2020 outburst, we place median 3Ҡlimits on the second-timescale NIR fluence of ?18 Jy ms (13.1 AB mag). The corresponding extinction-corrected limit is ?125 Jy ms for an estimated extinction of A_J = 2.0 mag. Our observations were sensitive enough to easily detect an NIR counterpart of FRB 200428 if the NIR emission falls on the same power law as observed across its radio to X-ray spectrum. We report nondetection limits from epochs of four simultaneous X-ray bursts detected by the Insight-HXMT and NuSTAR telescopes during our observations. These limits provide the most stringent constraints to date on fluence of flares at 10¹⁴ Hz, and constrain the fluence ratio of the NIR emission to coincident X-ray bursts to R_NIR ? 0.025 (fluence index ?0.35).

Comparison of simulated backgrounds with in-orbit observations for HE, ME, and LE onboard Insight-HXMT 期刊论文 OAI收割
Astrophysics and Space Science, 2020, 卷号: 365, 页码: 158
作者: HXMT

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收藏 | 浏览/下载：53/0 | 提交时间：2022/02/08

Insight-HXMT Geant4 simulation Background observation Astrophysics - Instrumentation and Methods for Astrophysics Abstract: Insight-HXMT, the first X-ray astronomical satellite in China, aims to reveal new sources in the Galaxy and to study fundamental physics of X-ray binaries from 1 to 250 keV. It has three collimated telescopes, the High Energy X-ray telescope (HE), the Medium Energy X-ray telescope (ME), and the Low Energy X-ray telescope (LE). Before the launch, in-orbit backgrounds of these three telescopes had been estimated through Geant4 simulation, in order to investigate the instrument performance and the achievement of scientific goals. In this work, these simulated backgrounds are compared with in-orbit observations. Good agreements are shown for all three telescopes. For HE, (1) the deviation of the simulated background rate after two years of operation in space is 5 % from the observation (2) the total background spectrum and the relative abundance of the 67 keV line show long-term increases both in simulations and observations. For ME, (1) the deviation of simulated background rate is within 15 % from the observation, and (2) there are no obvious long-term increase features in the background spectra of simulations and observations. For LE, the background level given by simulations is also consistent with observations. The consistencies of these comparisons validate that the Insight-HXMT mass model, i.e., space environment components and models adopted, physics processes selected, and detector constructions built, is reasonable. However, the line features at 7.5 and 8.0 keV, which are obvious in the observed spectra of LE, are not evident in simulations. This might result from uncertainties in the LE constructions.

A small electron beam ion trap/source facility for electron/neutral-ion collisional spectroscopy in astrophysical plasmas 期刊论文 OAI收割
RESEARCH IN ASTRONOMY AND ASTROPHYSICS, 2018, 卷号: 18, 页码: 1
作者: Zhao, Gang; Ma, Xin-Wen; Zschornack, Guenter; Schmidt, Mike; Zhu, Xiao-Long

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收藏 | 浏览/下载：31/0 | 提交时间：2018/05/31

X-ray: general atomic processes line: formation method: laboratory: atomic

A small electron beam ion trap/source facility for electron/neutral-ion collisional spectroscopy in astrophysical plasmas 期刊论文 OAI收割
RESEARCH IN ASTRONOMY AND ASTROPHYSICS, 2018, 卷号: 18, 期号: 1, 页码: 10
作者: Liang, Gui-Yun; Wei, Hui-Gang; Yuan, Da-Wei; Wang, Fei-Lu; Peng, Ji-Min

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收藏 | 浏览/下载：19/0 | 提交时间：2020/03/11

X-ray: general atomic processes line: formation method: laboratory: atomic

Refraction angle extracting strategy for fan-beam differential phase contrast CT 期刊论文 OAI收割
neurocomputing, 2014, 卷号: 141, 期号: si, 页码: 160-169
作者: Ye, Renzhen; Tang, Yi; Lu, Xiaoqiang

收藏 | 浏览/下载：29/0 | 提交时间：2015/03/18

Phase-contrast image X-ray imaging Fan-beam CT PI-line Gratings interferometer

Experimental exploration of Mouse kidney imaging with the SR PCI technology 期刊论文 OAI收割
BIO-MEDICAL MATERIALS AND ENGINEERING, 2014, 卷号: 24, 期号: 1, 页码: 1167-1172
作者: Xia, CC; Peng, YF; Arun, KY; Xiao, TQ; Zhu, PP

收藏 | 浏览/下载：18/0 | 提交时间：2016/04/08

Synchrotron radiation (SR) phase contrast imaging technology in-line outline X-ray imaging(IOXI) Mouse Kidney

Robust determination of mass attenuation coefficients of materials with unknown thickness and density 期刊论文 OAI收割
RADIATION PHYSICS AND CHEMISTRY, 2014, 卷号: 100, 页码: 65-69
作者: Kurudirek, M; Medhat, ME

收藏 | 浏览/下载：17/0 | 提交时间：2016/04/08

Mass attenuation coefficient X-ray line Beer-Lambert law Transmission geometry

SUPERMASSIVE BLACK HOLES WITH HIGH ACCRETION RATES IN ACTIVE GALACTIC NUCLEI. I. FIRST RESULTS FROM A NEW REVERBERATION MAPPING CAMPAIGN 期刊论文 OAI收割
ASTROPHYSICAL JOURNAL, 2014, 卷号: 782, 期号: 1
作者: SEAMBH collaboration

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SEYFERT 1 GALAXIES BROAD-LINE REGION AGN MONITORING PROJECT RADIUS-LUMINOSITY RELATIONSHIP SPECTRAL ENERGY-DISTRIBUTIONS DIGITAL SKY SURVEY X-RAY VARIABILITY COSMOLOGICAL EVOLUTION EDDINGTON RATIO OPTICAL VARIABILITY

SUPERMASSIVE BLACK HOLES WITH HIGH ACCRETION RATES IN ACTIVE GALACTIC NUCLEI. II. THE MOST LUMINOUS STANDARD CANDLES IN THE UNIVERSE 期刊论文 OAI收割
ASTROPHYSICAL JOURNAL, 2014, 卷号: 793, 期号: 2
作者: SEAMBH collaboration

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SEYFERT 1 GALAXIES BROAD-LINE REGION REVERBERATION MAPPING DATA SUPER-EDDINGTON ACCRETION HUBBLE-SPACE-TELESCOPE SELF-SIMILAR SOLUTION SLIM-DISK MODEL X-RAY EXCESS COSMOLOGICAL IMPLICATIONS OBSERVATIONAL APPEARANCE

Analysis of field of view limited by a multi-line X-ray source and its improvement for grating interferometry 期刊论文 OAI收割
analytical and bioanalytical chemistry, 2012, 卷号: 404, 期号: 3, 页码: 793-797
作者: Du, Yang; Huang, Jianheng; Lin, Danying; Niu, Hanben

收藏 | 浏览/下载：26/0 | 提交时间：2012/12/03

X-ray phase contrast imaging Grating interferometry Multi-line X-ray source Field of view