ORC's

[Superluminal]

http://www.sci-news.com/astronomy/od...les-08632.html
Something new to wonder about in this increasingly interesting universe.

[Noclevername]

A blind link?

[slang]

A blind link?

The title of the article is in the link, and it's not as if sci-news.com has a terrible reputation for spreading viruses... Please don't call out other members, please just use the report button if you think there might be an issue.

[Noclevername]

OK, to summarize; the article is about Odd Radio Circles, an astronomical phenomenon recently discovered on the meter wave band, source unknown.

[Jens]

http://www.sci-news.com/astronomy/od...les-08632.html
Something new to wonder about in this increasingly interesting universe.

I think the phenomenon is very interesting, and hope to read more about it. I just wanted to comment about "an increasingly interesting universe." I don't really agree. I think the universe has always been interested. What happens typically is that whenever a new instrument starts looking in a new band of the EM spectrum or at a higher resolution, we discover something new that has to be explained. Early on, after the discovery of x-rays, someone sent a balloon up into the atmosphere to make sure that (as predicted) the amount of x-rays would decrease with altitude, since it was believed they came from the earth's crust. When it turned out that they increased with altitude, it led to the discovery of cosmic rays. And lots of other things follow. So the universe has always been interesting, I think.

[Roger E. Moore]

More on ORCs, plus a paper on them just released.

https://phys.org/news/2020-12-newly-...y-current.html

===

https://arxiv.org/abs/2006.14805

Unexpected Circular Radio Objects at High Galactic Latitude

Ray P. Norris, Huib T. Intema, Anna D. Kapinska, Baerbel S. Koribalski, Emil Lenc, L. Rudnick, Rami Alsaberi, Craig Anderson, G. E. Anderson, E. Crawford, Roland Crocker, Jayanne English, Miroslav D. Filipovic, Andrew M. Hopkins, Natasha Hurley-Walker, Susumu Inoue, Kieran Luken, Peter Macgregor, Pero Manojlovic, Josh Marvil, Andrew N. O'Brien, Wasim Raja, Devika Shobhana, Tiziana Venturi, Jordan D. Collier, Catherine Hale, Aidan Hotan, Vanessa Moss, Matthew Whiting

We have found a class of circular radio objects in the Evolutionary Map of the Universe Pilot Survey, using the Australian Square Kilometre Array Pathfinder telescope. The objects appear in radio images as circular edge-brightened discs, about one arcmin diameter, that are unlike other objects previously reported in the literature. We explore several possible mechanisms that might cause these objects, but none seems to be a compelling explanation.

[Roger E. Moore]

Another ORC, or something else? Recent paper on a ring nebula unlike all others, 500 pc away.

https://arxiv.org/abs/2008.03975

A Mysterious Ring in Dark Space?

Wei Zhang, Fan Yang, Hong Wu, Chaojian Wu, Hu Zou, Tianmeng Zhang, Xu Zhou, Fengjie Lei, Junjie Jin, Zhimin Zhou, Jundan Nie, Jun Ma, Jiali Wang

We report the discovery of a low-surface-brightness (27.42 mag arcsec^(-2) in g band) nebula, which has a ring-like shape in the Beijing-Arizona Sky Survey (BASS). Positive detections have been found in multiband data from far ultraviolet to far infrared, except the z band from BASS and W1, W2 from the Wide-field Infrared Survey Explorer. The reddening of the nebula E(B - V) ~ 0.02 mag is estimated from Infrared Astronomical Satellite (IRAS) 100 micron intensity and HI column density. With the help of the 3D reddening map from Pan-STARRS 1, the Two Micron All Sky Survey, and Gaia, the distance to the nebula of about 500 pc from Earth is derived. Such a low-surface-brightness nebula whose energy can be interpreted by the diffuse Galactic light could account for the optical counterpart of the infrared cirrus, which was detected by IRAS more than 30 yr ago. The ring-like structure might be the ultimate phase of an evolved planetary nebula, while the central white dwarf star has been ejected from the nebula for an unclear reason. On the other hand, the ring structure being a superposition of two close filaments might be another reasonable explanation. Considering the lack of spectroscopic data and uncertainty in the distance measurement, these interpretations need to be checked by future observations.