diffuse radio emission with no IR counterpart
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by
WizardHowl
I've come across a few #IFRS examples but so far this is the only one where the radio emission is #diffuse . Given the size of the emission region, I would guess the source is nearby at low redshift, so there might be something in an optical survey?
Posted
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by
akapinska
scientist
in response to WizardHowl's comment.
Radio lobes are of diffuse radio emission. They are composed of the electron/positron plasma transported within the jets. The compact radio emission regions you often see in the lobes are where the jets hit their ambient medium.
I checked this source and it's a lobe of a faint double lobe radio galaxy - it is extending beyond this picture to the top right, and you can't see the second lobe. It's quite large, 3 arcminutes.
Sadly, sometimes it's not easy to guess whether the diffuse emission is a lobe or something else, unless it has some features that would hint.
Posted
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DocR
scientist
You have found the bottom half of a double radio source (an enormous one! -- I went and found it in another lower resolution survey, NVSS). The ID is unclear at the moment, perhaps the galaxy to the upper right of the diffuse emission. I'm going to dig deeper to check this out.
Posted
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DocR
scientist
OK, as best I can tell, this is the discovery of a possible new giant (3 Million light year across) radio galaxy! You can see the picture of the whole object at ![http://umn.edu/~larry/ARG0002gt4.jpg]. On the left is the radio image from the NVSS survey at lower resolution. Middle is FIRST survey, and the bottom half is what showed up in RGZ. On the right is the WISE (infrared, 3.6micron) image. The infrared galaxy doesn't have a firm distance on it (redshift = 0.263pm.024), but if it's right, this is part of a rare class of "giant radio galaxies" -- we do not understand yet how these enormous radio galaxies can be powered and live for so long to reach their enormous size. Great work of discovery, WizardHowl! [I hope this pans out on further checking!]
Posted
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by
HAndernach
scientist, translator
I also checked the source and found (as Larry did) the optical counterpart
corresponding to the WISE source to be SDSS J103647.88+181135.5 (see
http://skyserver.sdss3.org/dr10/en/tools/explore/summary.aspx?id=0x112d172f811c0094&spec=&apid= )However, adopting the mean of two estimated redshifts (0.26 +- 0.03)
at the bottom of that page, and the radio source size of 3.0 arcmin,
even using the most distant redshift estimate (0.3) I obtain 770
kpc for current standard cosmology (H0=71). It's a very large radio
galaxy (2 million light years) but does not reach the one megaparsec
threshold (or 3.26 million light years) using considered for being
"giant radio galaxies". Certainly real giants are bound to be discovered
in RadioGalaxyZoo.Posted
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by
DocR
scientist
Even though it doesn't meet the formal category mentioned above, for the purposes of RGZoo, we can call this type of source a #giant
Posted
