IR Star with a Speech Bubble??
In the IR I have seen two "explosions of light" like the one in this image. Please can you tell me what they are?
Also I have seen IR images of stars with what looks like lensing from behind, but there are more instances of them than I would have expected and one definitely seemed to have caused the radio signals to present in the same way. Do radio signals also bend around the larger mass objects?
Here's an SDSS image of this field, centered on what I think is the host of the radio source in the center, a galaxy called SDSS J174004.92+572305.3, with a photometric redshift of 0.169±0.025:
The "explosions of light"? That's a bright star.
The design of the telescopes - WISE for the IR image in the ARG field, SDSS for the optical one above - guarantees that there will be 'compass points' (they're called diffraction spikes), rings (seen in the SDSS image at least), and the extended "explosion". How does this happen? Mostly it's just scattering of the light of the star by various parts of the telescopes and cameras ... no matter how black you make a supporting structure (a telescope tube, say), it will still reflect some light. In SDSS, some of the 'stray light' is due to scattering by dust etc in the atmosphere above the telescope.
Also I have seen IR images of stars with what looks like lensing from behind, but there are more instances of them than I would have expected and one definitely seemed to have caused the radio signals to present in the same way.
Do you have some specific examples?
Do radio signals also bend around the larger mass objects
Yes, in theory they do.
However, the extent of the bending is the same as that for light, infra-red, x-rays, etc ... bending due to gravitation is 'achromatic' (i.e. the same no matter what the wavelength is).
As far as I know, the largest known lensed structure, in terms of apparent size 'on the sky, is less than an arcminute, and most are less than ~5 arcseconds (5"). That means that very few known lens structures would be 'visible' as such in the radio data we are using (from the FIRST survey), assuming the sources are the same in radio as they are in infrared (say).
Why? Because the smallest structure that can be seen - 'resolved' in astronomer-speak - is ~5". So you can expect to see no lensing in any of the RGZ images we get to classify.
But the universe keeps surprising us! 😮 So if you see what you think is a good lensing candidate, write a post on it!
Hope this helps, and happy hunting! 😃