<p>They don't need to be pointed exactly at us, since the angular beam radius is a few degrees (<a href="https://books.google.ca/books?id=jCPn3v-o_KoC&amp;pg=PA211&amp;lpg=PA211&amp;dq=pulsars+%22beam+radius%22&amp;source=bl&amp;ots=hTFfWOblsO&amp;sig=ACfU3U3-e7zZcuwK1zdNUY7dtc7txMdU5A&amp;hl=en&amp;sa=X&amp;ved=2ahUKEwjZ4JPsv8DmAhWQrJ4KHR4ACLU4ChDoATAEegQIChAB#v=onepage&amp;q=pulsars%20%22beaming%20factor%22&amp;f=false0" rel="nofollow noreferrer">Pulsar Astronomy, P. 212</a>) but there is a portion that we can't detect, described by a beaming factor (P. 211):  </p>

<p><a href="https://i.sstatic.net/wFV7d.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/wFV7d.png" alt="enter image description here"></a>  </p>

<p>The larger beamwidth at higher energies can be seen in these graphs:</p>

<p><a href="https://i.sstatic.net/b7JJs.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/b7JJs.png" alt="enter image description here"></a><br>
<a href="https://fermi.gsfc.nasa.gov/science/mtgs/gevtev/june16/Manchester_Beams_Aspen.pdf#page=9" rel="nofollow noreferrer">R. N. Manchester </a></p>

<p>We mostly can't see "ordinary neutron stars". <a href="https://en.wikipedia.org/wiki/Neutron_star" rel="nofollow noreferrer">"neutron stars can only be easily detected in certain instances, such as if they are a pulsar or part of a binary system" - Wikipedia</a></p>

<p>If the pulsar is radiating gamma rays more isotropically (but still varying with phase as in the Manchester charts), then these could be detected.</p>

CC BY-SA 4.0
2019-12-19T09:09:33.233Z
So even if we manage to detect a neutron star, if the beam isn't roughly pointed towards us, there is no way of knowing that it is a pulsar.
usernumber
CC BY-SA 4.0
2019-12-19T18:08:38.673Z
@usernumber [This](https://chandra.harvard.edu/photo/2017/geminga/) might be an example: "For Geminga, astronomers view the bright gamma-ray pulses along the edge of the torus, but the radio beams near the jets point off to the sides and remain unseen"
Keith McClary
CC BY-SA 4.0
2019-12-20T04:45:49.707Z
@usernumber New [article about Geminga](https://phys.org/news/2019-12-fermi-mission-links-nearby-pulsar.html).
Keith McClary
CC BY-SA 4.0
2020-01-29T11:04:33.447Z
This is actually avoiding the question. I take it your answer is no?
ProfRob
CC BY-SA 4.0
2019-12-19T03:46:36.877Z
2020-01-30T03:34:18.003Z
2020-01-30T03:34:18.003Z
Keith McClary
<p>A pulsar is a highly magnetized rotating neutron star that emits beams of radiation through its magnetic poles, in the direction of the Earth. This makes it seem to pulse, as seen from Earth. There likely are similar objects that pulse as seen from other directions, but not from Earth. Can we tell the difference between one of these objects and an ordinary neutron star?</p>

<p>Is there any way of detecting pulsars that are not pulsing in our direction?</p>

<neutron-star><pulsar>
Can we detect pulsars that aren't "pointed" towards us?
usernumber
# Can we detect pulsars that aren't "pointed" towards us?

(Asked by: username_0 on 2019-12-17)

A pulsar is a highly magnetized rotating neutron star that emits beams of radiation through its magnetic poles, in the direction of the Earth. This makes it seem to pulse, as seen from Earth. There likely are similar objects that pulse as seen from other directions, but not from Earth. Can we tell the difference between one of these objects and an ordinary neutron star?

Is there any way of detecting pulsars that are not pulsing in our direction?

**Tags:** neutron-star, pulsar

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## 1 answers

### Answer by username_1 on 2019-12-19. Score: 8 | Accepted answer

They don't need to be pointed exactly at us, since the angular beam radius is a few degrees ([Pulsar Astronomy, P. 212](https://books.google.ca/books?id=jCPn3v-o_KoC&pg=PA211&lpg=PA211&dq=pulsars+%22beam+radius%22&source=bl&ots=hTFfWOblsO&sig=ACfU3U3-e7zZcuwK1zdNUY7dtc7txMdU5A&hl=en&sa=X&ved=2ahUKEwjZ4JPsv8DmAhWQrJ4KHR4ACLU4ChDoATAEegQIChAB#v=onepage&q=pulsars%20%22beaming%20factor%22&f=false0)) but there is a portion that we can't detect, described by a beaming factor (P. 211):

[![enter image description here](https://i.sstatic.net/wFV7d.png)](https://i.sstatic.net/wFV7d.png)

The larger beamwidth at higher energies can be seen in these graphs:

[![enter image description here](https://i.sstatic.net/b7JJs.png)](https://i.sstatic.net/b7JJs.png)  
[R. N. Manchester](https://fermi.gsfc.nasa.gov/science/mtgs/gevtev/june16/Manchester_Beams_Aspen.pdf#page=9)

We mostly can't see "ordinary neutron stars". ["neutron stars can only be easily detected in certain instances, such as if they are a pulsar or part of a binary system" - Wikipedia](https://en.wikipedia.org/wiki/Neutron_star)

If the pulsar is radiating gamma rays more isotropically (but still varying with phase as in the Manchester charts), then these could be detected.

> **Comments:**
> **username_0**: So even if we manage to detect a neutron star, if the beam isn't roughly pointed towards us, there is no way of knowing that it is a pulsar.  
> **username_1**: @usernumber [This](https://chandra.harvard.edu/photo/2017/geminga/) might be an example: "For Geminga, astronomers view the bright gamma-ray pulses along the edge of the torus, but the radio beams near the jets point off to the sides and remain unseen"  
> **username_1**: @usernumber New [article about Geminga](https://phys.org/news/2019-12-fermi-mission-links-nearby-pulsar.html).  
> **username_2**: This is actually avoiding the question. I take it your answer is no?  

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