scholarly journals Radio, optical and X-ray emission from pulsars

1970 ◽  
Vol 37 ◽  
pp. 196-201
Author(s):  
B. Bertotti ◽  
A. Cavaliere ◽  
F. Pacini
Keyword(s):  
Radio Emission ◽  
Correlation Length ◽  
Crab Nebula ◽  
Infrared Emission ◽  
Appreciable Amount ◽  
Electromagnetic Spectrum ◽  
X Ray ◽  
The Crab Nebula

We examine the electromagnetic spectrum of the Crab Nebula pulsar NP 0532. The present observations are in rough agreement with the idea that the orbit of the radiating particles involves two different radii of curvature. One of the possible models requires electrons with a typical energy of the order of 100 MeV and a density ≈ 109 cm−3. A correlation length of about 10 cm could then give the coherence of the radio emission. Slow pulsars are unlikely to emit an appreciable amount of optical or X-ray radiation but a weak infrared emission is possible.

scholarly journals Peculiar Differences in Radio and X-ray Synchrotron Radiation from Pulsar Wind Nebulae

2004 ◽  
Vol 218 ◽  
pp. 221-224
Author(s):  
John R. Dickel ◽  
Shiya Wang
Keyword(s):  
Synchrotron Radiation ◽  
Radio Emission ◽  
Supernova Remnants ◽  
Crab Nebula ◽  
Pulsar Wind Nebulae ◽  
X Ray ◽  
Pulsar Wind ◽  
The Crab Nebula

Several Crab-type supernova remnants appear to have very bright non-thermal X-ray cores just around the pulsar or expected pulsar. This X-ray brightness is often not matched by a corresponding increase in radio emission. The best example of this phenomenon is in N157B in the LMC. G21.5−0.9 and possibly 3C 58 also show it while the Crab Nebula and 0540−69.3 do not. Some method to enhance the higher energy particles must be present in these objects.

scholarly journals The electromagnetic spectrum of the Crab Nebula

1970 ◽  
Vol 37 ◽  
pp. 247-249
Author(s):  
Krishna M. V. Apparao
Keyword(s):  
Compton Scattering ◽  
Power Law ◽  
Crab Nebula ◽  
High Energy ◽  
Electromagnetic Spectrum ◽  
Microwave Region ◽  
X Ray ◽  
High Energy Electrons ◽  
Γ Ray ◽  
The Crab Nebula

The electromagnetic spectrum of the Crab Nebula has been determined experimentally in the radio, optical, and X-ray regions [1], in which it follows a power law of the type S(v) = Av−α, where S(v) is the power (in watts/m2 sec Hz), A and α are constants, and v is the frequency in Hz. Recent measurements [2–5], however, show a deviation from a power law in the microwave region (see Figure 1). In this paper, we investigate the origin of this deviation and calculate the γ-Ray spectrum due to this increase in the microwave photons via the Compton scattering from high-energy electrons.

scholarly journals The Secular Behavior of X-Ray and Radio Emission from Supernova Remnants

1971 ◽  
Vol 46 ◽  
pp. 268-272
Author(s):  
Wallace H. Tucker
Keyword(s):  
Radio Emission ◽  
Supernova Remnants ◽  
Crab Nebula ◽  
X Ray ◽  
Cas A ◽  
The Crab Nebula ◽  
Continuous Injection

Continuous injection models for the secular behavior of the radio and X-ray emission from supernova remnants are examined and compared with the observations. Among other things, it is concluded that (1) continuous injection probably occurs for at least 10 yr in every case and about 1000 yr in most supernova remnants, in which case the supernova remnants 3C392, W28, Pup A and IC443 should produce 1–10 keV X-ray fluxes ≈ 10-10 ergs/cm2-sec, and (2) the X-ray sources in the Crab Nebula, Cas A and Tycho can be explained in terms of a model wherein continuous injection occurs for 300 yr for the Crab Nebula, much less than 250 yr for Cas A and much longer than 400 yr for Tycho. Finally, it is shown that if Tycho and Cas A contain an X-ray star such as NP 0532, it is quite possible that the X-ray emission from those sources is predominantly due to the X-ray star.

scholarly journals The Electromagnetic Spectrum of the Crab Nebula

1971 ◽  
Vol 46 ◽  
pp. 22-31 ◽  
Author(s):  
J. E. Baldwin
Keyword(s):  
Flux Density ◽  
Spectral Index ◽  
Crab Nebula ◽  
Electromagnetic Spectrum ◽  
Optical Range ◽  
X Ray ◽  
Radio Data ◽  
A Value ◽  
The Crab Nebula

I shall discuss observations of the spectrum of the integrated emission from the Crab Nebula. The radio data with accurate calibrations lead to a flux density spectral index of −0.26. Discrepancies in the published fluxes at millimetre wavelengths can be resolved if appropriate angular dimensions are used. In the optical range the spectral index has increased to a value of −0.9 if 1m.0 of absorption is used. At X-ray wavelengths the spectral index has increased further to −1.2.

scholarly journals Variable Radio Emission from X-Ray Sources

1971 ◽  
Vol 15 ◽  
pp. 173-175 ◽  
Author(s):  
L. L. E. Braes ◽  
G. K. Miley
Keyword(s):  
Radio Emission ◽  
Aperture Synthesis ◽  
Electromagnetic Spectrum ◽  
Radio Telescopes ◽  
Low Resolution ◽  
X Ray ◽  
Synthesis Technique ◽  
Variable Radio

Dr. KELLOGG has just described some exciting new observations of X-ray sources made with the UHURU satellite. We shall now move some nine orders of magnitude in wavelength to the opposite end of the electromagnetic spectrum and report measurements of weak radio emission from some of the objects he mentioned. For the detection of weak sources most radio telescopes are not noise limited, but are confusion limited by their low resolution. The aperture synthesis technique minimizes this problem because it enables one to pinpoint the position of weak sources to the order of one second of arc.

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 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.

Sign in / Sign up

Export Citation Format

Share Document