# Tag Info

1

@uhoh, I hope this answers your first question. I sourced the following 2 paras from the link : https://www.nbcnews.com/mach/science/has-mysterious-signal-space-finally-been-explained-ncna771671 Two big issues are that the signal didn't repeat, and it appeared for such a short time. Ehman noted that the Big Ear telescope had two "feed horns," each ...

0

How did Jocelyn Bell Burnell discover the periodicity of CP 1919? Supplemental to @RoryAlsop's answer refer to Astrobytes' The First Pulsar which discusses the Nature paper (A. Hewish, S. J. Bell, J. Pilkington, P. Scott, and R. Collins 1968) Observation of a Rapidly Pulsating Radio Source and shows Figure 2 from the paper. For more on the radio telescope ...

5

Small quibble to the (rightfully) accepted answer by James K that was too long for a comment: To be fair, $x=24^{+1}_{-3}$ doesn't mean that $21 \le x \le 25$, but that with a particular amount of certainty (usually 68%), $21 \le x \le 25$. Correspondingly, $x=24^{\times 2}_{\div3}$ would mean that, with some certainty, $8 \le x \le 48$. Symmetric vs. ...

4

Yes - at that time, the chart was the source of data used for analysis. Jocelyn visually reviewed hundreds of metres of traces every night looking for quasars (the reason the Interplanetary Scintillation Array was built) The wiggle looked different from expected signals, and in fact was misidentified as interference at first, but when she noticed it again, ...

4

A notation like $x=24^{+1}_{-3}$ is quite common, it means $24-3<x<24+1$ with a best estimate of 24, and is a way of indicating uncertainty. The example you give is less common, by analogy $x=24^{\times 2}_{\div3}$ means $24\div3 < x < 24\times 2$ ie $x$ is between 8 and 48, with a best estimate of 24

6

A confirmation of the explanation is given slightly further on where it talks about how the uncertainty is derived: In equation (4) we use the 0.6 dex scatter of $\log L_{\rm UV}$ around the $L_{\rm UV}$ versus $L_{\rm [O\ III]}$ relation, as an estimate for the uncertainty in deriving $L_{\rm bol}$ from $L_{\rm [O\ III]}$. The term "dex" ...

5

Her Wikipedia page also includes this picture (public domain), where she wears the same dress, and where a similar display can be seen in the background: Roman sits at the control console for the Orbiting Astronomical Observtory satellite, launched in 1972 and nicknamed Copernicus. This is a publicity picture; she never actually worked in the Goddard ...

5

Two things would be required. First, your line of sight would have to be close to looking along the magnetic axis of the neutron star. Second, that magnetic axis would have to be closely aligned with the rotation axis of the pulsar. If both of these are pseudo-randomly distributed and the pulsar beam is narrow, then this is inherently a very unlikely ...

4

The electromagnetic radiation comes from accelerated charged particles, mainly electrons and positrons. The surface of a neutron star is not made of neutrons. It is a totally ionised gas of nuclei plus electrons, with a composition that could range from iron-peak elements to hydrogen and helium accreted from the interstellar medium. As a result of their ...

0

It depends on what you mean by "just Jy". Usually, what is meant is the surface brightness of a source, in some unit like $\operatorname{Jy}\operatorname{sr}^{-1}$ or $\operatorname{Jy}\operatorname{arcsec}^{-2}$, integrated over solid angle to get the source's total flux. What a measurement of $I \operatorname{Jy}\operatorname{beam}^{-1}$ is ...

8

From "The 10.7 cm solar radio flux ($F_{10.7}$)", It has become clear that wavelengths in the region of 10 cm are best for monitoring the level of solar activity because solar emissions at these wavelengths are very sensitive to conditions in the upper chromo- sphere and at the base of the corona. This is not saying that exactly 10 cm wavelength ...

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