ARG0001s0y - restarted twice?

• by JeanTate

  ARG0001s0y looks to me like it has three distinct pairs of hotspots; does that mean it's had three separate eruptive events?

  Host may be SDSS J162754.63+290620.0 (the red one) or SDSS J162754.47+290610.6 (the green one)

  

  Posted June 18, 2015 8:50 PM

• by ivywong scientist, admin

  Possibly. Definitely more than once I think.

  Posted June 19, 2015 4:55 AM

• by JeanTate in response to JeanTate's comment.

  A nice NVSS/FIRST contour overlay on SDSS:

  
  
  

  Will need a zoom-in overlay to decide which galaxy is the host ...

  The image in this post was created from sources, and using methods, described in this RGZ Talk post. The object at the center of the image is SDSS J162754.63+290620.0

  Posted July 28, 2015 12:43 AM

• by 42jkb scientist, admin

  How many restarted candidates are there? Do you know if RGZ has found many?

  Posted July 28, 2015 10:40 AM

• by JeanTate in response to 42jkb's comment.

  Hard to say, but there are - per RGZ Talk's Search - 197 hits for "#restarted". Of these, 33 refer to Talk threads (so they may duplicate another hit), 1 a Collection (antikodon's RSRG), and the rest to RGZ frames (presumably via a Comment).

  antikodon's Collection has a mere 38 fields; being antikodon - one of the super RGZ zooites - I'm sure almost all of them are indeed restarted. I did a spot check and found none have the hashtag #restarted!

  OOM (order of magnitude) then, ~2-2.5 (i.e. ~80-300) ... with perhaps many more unidentified

  Posted July 28, 2015 1:47 PM

• by 42jkb scientist, admin in response to JeanTate's comment.

  I'll have a look at the science projects and see if anyone is working on these types of objects.

  Posted July 28, 2015 11:37 PM

• by akapinska scientist

  I'll jump in to the discussion if I may. I don't see a third pair of hotspots here... But anyway, even if restarted once, the source is interesting as you could actually see two pairs of hotspots - once the jets stop the hotspots will disappear very quickly (~10,000 yrs) and so if they are still there then the time off must have been very short!

  As for sources restarted twice, I think there is only one example known so far! I'll try to find the reference

  Posted August 5, 2015 1:28 PM

• by akapinska scientist

  ah, there it is!

  http://adsabs.harvard.edu/abs/2007MNRAS.382.1019B

  Posted August 5, 2015 1:31 PM

• by JeanTate in response to akapinska's comment.

  Cool! 😃

  Perhaps I'm looking too closely, but I think there may be four pairs of hotspots! 😮

  But anyway, even if restarted once, the source is interesting as you could actually see two pairs of hotspots

  One confounding factor: are (quite distinct) local maxima in a lobe hotspots (or are they just 'knots' in a jet)? If there are quite distinct pairs of such, how certainly can we say they are 'restarted' episodes?

  I particularly wonder because the extent of a lobe surely depends on the depth of the observation, right? So a 'restarted' pair of lobes/hotspots is - at least to some extent - dependent on how deep the radio observations are, right? Not to mention what different resolution observations show (in this case, NVSS 'sees' just a simple doublelobe, but FIRST sees at least two pairs).

  And it gets more difficult to tell if the lobes are strongly asymmetric (as are quite a few, in RGZ) ...

  Posted August 5, 2015 4:09 PM

• by akapinska scientist in response to JeanTate's comment.

  But anyway, even if restarted once, the source is interesting as you could actually see two pairs of hotspots

  One confounding factor: are (quite distinct) local maxima in a lobe hotspots (or are they just 'knots' in a jet)?

  yeah.. that really depends on the source, and indeed sometimes there may be jet knots or some other flares, which are not hotspots

  I particularly wonder because the extent of a lobe surely depends on the depth of the observation, right? So a 'restarted' pair of lobes/hotspots is - at least to some extent - dependent on how deep the radio observations are, right? Not to mention what different resolution observations show (in this case, NVSS 'sees' just a simple doublelobe, but FIRST sees at least two pairs).

  Yes, e.g. have a look at this paper: http://adsabs.harvard.edu/abs/2013ApJ...765L..11S

  Posted August 5, 2015 5:24 PM

• by JeanTate in response to JeanTate's comment.

  Zoomed in FIRST contour overlay image:

  

  The image in this post was created from sources, and using methods, described in this RGZ Talk post. The object at the center of the image is SDSS J162754.63+290620.0

  Posted September 16, 2015 11:52 AM