scholarly journals X-ray Study of the Crab Nebula and the Crab and Vela Pulsars

1983 ◽  
Vol 101 ◽  
pp. 131-138
Author(s):  
F. R. Harnden

The Crab Nebula has been intensely studied by X-ray astronomers ever since its discovery as the first, optically identified X-ray object (Bowyer et al. 1964); and a large majority of X-ray experiments during the past two decades have observed the Crab, seeking not only the answers to scientific questions but also assurance that the instruments' calibrations were understood. It is therefore no surprise that, following its launch in 1978 November, the Einstein X-ray Observatory too had the Crab Nebula on its list of mandatory targets.

2020 ◽  
Author(s):  
Satoru Katsuda ◽  
Hitoshi Fujiwara ◽  
Yoshitaka Ishisaki ◽  
Yoshitomo Maeda ◽  
Koji Mori ◽  
...  

2013 ◽  
Vol 65 (4) ◽  
pp. 74 ◽  
Author(s):  
Tomomi Kouzu ◽  
Makoto S. Tashiro ◽  
Yukikatsu Terada ◽  
Shin’ya Yamada ◽  
Aya Bamba ◽  
...  

1968 ◽  
Vol 1 ◽  
pp. 202-205
Author(s):  
Laurence E. Peterson

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.


1971 ◽  
Vol 46 ◽  
pp. 394-406
Author(s):  
F. Pacini

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.


1971 ◽  
Vol 46 ◽  
pp. 296-307 ◽  
Author(s):  
D. B. Melrose

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.


2004 ◽  
Vol 218 ◽  
pp. 181-184 ◽  
Author(s):  
Koji Mori ◽  
David N. Burrows ◽  
George G. Pavlov ◽  
J. Jeff Hester ◽  
Shinpei Shibata ◽  
...  

We present year-scale morphological variations of the Crab Nebula revealed by the Chandra X-ray Observatory. Observations have been performed about every 1.7 years over the three years from launch. The variations are clearly recognized at two sites: the torus and the southern jet. The torus, which had been steadily expanding until 1.7 years ago, now appears to have shrunk in the latest observation. Additionally, the circular structures seen to the northeast of the torus have decayed into several arcs. On the other hand, the southern jet shows the growth of its overall kinked-structure. We discuss the nature of these variations in terms of the pulsar wind nebula mechanism.


2004 ◽  
Vol 218 ◽  
pp. 185-188
Author(s):  
Patrick Slane

As the presumed remnant of SN 1181, 3C 58 houses one of the youngest known neutron stars in the Galaxy. The properties of this young pulsar and its associated pulsar wind nebula (PWN) differ considerably from those of the Crab Nebula, and may well offer a more typical example of the endpoint of massive star collapse. High resolution X-ray studies reveal structures in the inner nebula that may be associated with the pulsar wind termination shock, a jet that may be aligned with the rotation axis, and other regions of enhanced emission. Spectral variations in the PWN are consistent with the expected evolution of the postshock flow, and complex loops of emission are seen in the nebula interior. Limits on the neutron star surface temperature fall below standard cooling models, indicating that some more rapid neutrino cooling process is required. The outer regions of 3C 58 show thermal emission with enhanced levels of neon, indicative of shocked ejecta bounding the PWN.


2015 ◽  
Vol 801 (1) ◽  
pp. 66 ◽  
Author(s):  
Kristin K. Madsen ◽  
Stephen Reynolds ◽  
Fiona Harrison ◽  
Hongjun An ◽  
Steven Boggs ◽  
...  

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