scholarly journals Measurement of vertical atmospheric density profile from the X-ray Earth occultation of the Crab Nebula with Insight-HXMT

2022 ◽  
Author(s):  
Daochun Yu ◽  
Haitao Li ◽  
Baoquan Li ◽  
Mingyu Ge ◽  
Youli Tuo ◽  
...  
Keyword(s):  
Energy Range ◽  
Density Profile ◽  
Crab Nebula ◽  
Model Parameters ◽  
Atmospheric Density ◽  
Altitude Range ◽  
Density Profiles ◽  
X Ray ◽  
Posterior Probability Distribution ◽  
The Crab Nebula

Abstract. The X-ray Earth occultation sounding (XEOS) is an emerging method for measuring the neutral density in the lower thermosphere. In this paper, the X-ray Earth occultation (XEO) of the Crab Nebula is investigated by using the Insight-HXMT. The pointing observation data on the 30th September, 2018 recorded by the Low Energy X-ray telescope (LE) of Insight-HXMT are selected and analyzed. The extinction lightcurves and spectra during the X-ray Earth occultation process are extracted. A forward model for the XEO lightcurve is established and the theoretical observational signal for lightcurve is predicted. A Bayesian data analysis method is developed for the XEO lightcurve modeling and the atmospheric density retrieval. The posterior probability distribution of the model parameters is derived through the Markov Chain Monte Carlo (MCMC) algorithm with the NRLMSISE-00 model and the NRLMSIS 2.0 model as basis functions and the best-fit density profiles are retrieved respectively. It is found that in the altitude range of 105–200 km, the retrieved density profile is 88.8 % of the density of NRLMSISE-00 and 109.7 % of the density of NRLMSIS 2.0 by fitting the lightcurve in the energy range of 1.0–2.5 keV based on XEOS method. In the altitude range of 95–125 km, the retrieved density profile is 81.0 % of the density of NRLMSISE-00 and 92.3 % of the density of NRLMSIS 2.0 by fitting the lightcurve in the energy range of 2.5–6.0 keV based on XEOS method. In the altitude range of 85–110 km, the retrieved density profile is 87.7 % of the density of NRLMSISE-00 and 101.4 % of the density of NRLMSIS 2.0 by fitting the lightcurve in the energy range of 6.0–10.0 keV based on XEOS method. The measurements of density profiles are compared with the NRLMSISE-00/NRLMSIS 2.0 model simulations and the previous retrieval results with RXTE satellite. Finally, we find that the retrieved density profile from Insight-HXMT based on the NRLMSISE-00/NRLMSIS 2.0 models is qualitatively consistent with the previous retrieved results from RXTE. This study demonstrate that the XEOS from the X-ray astronomical satellite Insight-HXMT can provide an approach for the study of the upper atmosphere. The Insight-HXMT satellite can join the family of the XEOS. The Insight-HXMT satellite with other X-ray astronomical satellites in orbit can form a space observation network for XEOS in the future.

scholarly journals New Measurement of the Vertical Atmospheric Density Profile from Occultations of the Crab Nebula with X-Ray Astronomy Satellites Suzaku and Hitomi

2020 ◽  
Author(s):  
Satoru Katsuda ◽  
Hitoshi Fujiwara ◽  
Yoshitaka Ishisaki ◽  
Yoshitomo Maeda ◽  
Koji Mori ◽  
...  
Keyword(s):  
Density Profile ◽  
Crab Nebula ◽  
Atmospheric Density ◽  
X Ray ◽  
The Crab Nebula

scholarly journals New Measurement of the Vertical Atmospheric Density Profile from Occultations of the Crab Nebula with X-Ray Astronomy Satellites Suzaku and Hitomi

2021 ◽  
Author(s):  
Satoru Katsuda ◽  
Hitoshi Fujiwara ◽  
Yoshitaka Ishisaki ◽  
Yoshitomo Maeda ◽  
Koji Mori ◽  
...  
Keyword(s):  
Density Profile ◽  
Crab Nebula ◽  
Atmospheric Density ◽  
X Ray ◽  
The Crab Nebula

scholarly journals New Measurement of the Vertical Atmospheric Density Profile From Occultations of the Crab Nebula With X‐Ray Astronomy Satellites Suzaku and Hitomi

2021 ◽  
Vol 126 (4) ◽  
Author(s):  
Satoru Katsuda ◽  
Hitoshi Fujiwara ◽  
Yoshitaka Ishisaki ◽  
Maeda Yoshitomo ◽  
Koji Mori ◽  
...  
Keyword(s):  
Density Profile ◽  
Crab Nebula ◽  
Atmospheric Density ◽  
X Ray ◽  
The Crab Nebula

Low-energy cosmic X-ray measurements

1969 ◽  
Vol 47 (23) ◽  
pp. 2651-2666 ◽  
Author(s):  
A. J. Baxter ◽  
B. G. Wilson ◽  
D. W. Green
Keyword(s):  
Spectral Analysis ◽  
Energy Range ◽  
Crab Nebula ◽  
Spectral Characteristics ◽  
Low Energy ◽  
Data Recovery ◽  
X Rays ◽  
X Ray ◽  
Recovery System ◽  
The Crab Nebula

An experiment is described to investigate cosmic X rays in the energy range 0.25–12 keV. The data-recovery system and methods of spectral analysis are considered. Results are presented for the energy spectrum of the diffuse X-ray component and its distribution over the northern sky down to 1.6 keV with a limited extension at 0.27 keV.In the energy range 1.6 to 12 keV, the spectrum is represented by:[Formula: see text]although separate analyses indicate a flattening below 4.5 keV to give:[Formula: see text]and[Formula: see text]At the lowest energies, the flux appears to increase more rapidly and exhibits some anisotropy in arrival directions related to the gross galactic structure. Spectral characteristics of the Crab Nebula and Cygnus X-2 have also been determined.

scholarly journals Spectral Variation of Hard X-Ray Emission from the Crab Nebula with the Suzaku Hard X-Ray Detector

2013 ◽  
Vol 65 (4) ◽  
pp. 74 ◽  
Author(s):  
Tomomi Kouzu ◽  
Makoto S. Tashiro ◽  
Yukikatsu Terada ◽  
Shin’ya Yamada ◽  
Aya Bamba ◽  
...  
Keyword(s):  
Crab Nebula ◽  
Spectral Variation ◽  
X Ray ◽  
The Crab Nebula

scholarly journals The X-Ray Spectra of Cygnus XR-1 and the Crab Nebula

1968 ◽  
Vol 1 ◽  
pp. 202-205
Author(s):  
Laurence E. Peterson
Keyword(s):  
Power Law ◽  
Crab Nebula ◽  
Atmospheric Depth ◽  
Significance Level ◽  
X Ray ◽  
One Year ◽  
The Crab Nebula

In this paper we wish to present briefly the latest results which have been obtained on the hard X-ray spectra of two strong sources in the Northern skies. These observations, which have been discussed in detail previously (Peterson et al., 1967), were made from balloons launched at Palestine, Texas, to 3 gm/cm2 atmospheric depth during September 1966. The Crab Nebula and the Cygnus XR-1 were observed to have a differential number power law spectra with an index of about –2 over the 20–200 keV range. Both sources have the same intensity within about 10%. The Crab Nebula has been observed on two occasions, one year apart, and showed no change in intensity over this range at about a 5% significance level.

scholarly journals Physical Processes and Parameters in the Magnetosphere of NP 0532

1971 ◽  
Vol 46 ◽  
pp. 394-406
Author(s):  
F. Pacini
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Supernova Remnants ◽  
Crab Nebula ◽  
General Relation ◽  
Energy Generation ◽  
Main Pulse ◽  
Physical Processes ◽  
X Ray ◽  
The Crab Nebula

The Crab Nebula pulsar conforms to the model of a rotating magnetised neutron star in the rate of energy generation and the exponent of the rotation law.It is suggested that the main pulse is due to electrons and the precursor to protons. Both must radiate in coherent bunches. Optical and X-ray radiation is by the synchrotron process.The wisps observed in the Nebula may represent the release of an instability storing about 1043 erg and 1047–48 particles.Finally, some considerations are made about the general relation between supernova remnants and rotating neutron stars.

scholarly journals Transfer of Energy to the Crab Nebula Following the Spin-Up of the Pulsar

1971 ◽  
Vol 46 ◽  
pp. 296-307 ◽  
Author(s):  
D. B. Melrose
Keyword(s):  
Energy Flux ◽  
Central Region ◽  
Crab Nebula ◽  
Point Of View ◽  
Relativistic Electrons ◽  
Synchrotron Emission ◽  
X Ray ◽  
Enhanced Activity ◽  
The Crab Nebula

Observed enhanced activity in the central region of the Crab Nebula following the spin-up of the pulsar is discussed from the point of view of the transfer of energy to relativistic electrons. It is argued that a rapid deposition of energy associated with the spin-up of the pulsar causes a radial energy flux which becomes a flux in hydromagnetic activity at about the regions where enhanced synchrotron emission is observed. It is shown that such hydromagnetic activity is rapidly damped by the relativistic electrons with energy being transferred to the relativistic electrons. This acceleration can account for the short synchrotron halflifetimes observed. The model predicts highly enhanced X-ray emission from the central region of the Nebula following a spin-up.

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