The shoulder of Giants
To stand on the shoulder of giants, we first have to find them. In Radio Galaxy Zoo, we are of course referring to the hunt for Giant Radio Galaxies. These Giants can provide us with valuable insights into the environment in which they reside as well as the evolution of radio AGN. In this post, I will present a summary of the highlights that Heinz A. has reported on RGZ’s search for Giants in 2016.
As of late September 2016, RGZ citizen scientists have uncovered at least 313 Giant candidates which are larger than 1 Mpc in projected size. Of the 313, 201 are new discoveries made by RGZ! Of course, follow-up observations and further verification checks are required. However, this is still fantastic job and no small feat by the team. A big thank you goes to RG Zooite Antikodon & Dolorous_Edd for paving the way again and discovering ~78% of these Giant candidates. To put things into perspective, if one wanted to extract a list of Giants from the NASA Extragalactic Database (NED; a well-known archive used by professional astronomers) one would find only 55 objects tagged as Giant Radio Galaxies! This is partly due to the fact that in publications such objects are not always explicitly labelled as such. Here is Heinz’s table comparing the properties of the published Giants versus the newly-discovered RGZ candidates :
|Property||Published||New RGZ candidates|
|Median linear size (Mpc)||1.3||1.18|
|Number (size> 2 Mpc)||29||6|
It is clear that RGZ is leading the pack in collating and cataloguing these unusual radio galaxies. With our upcoming observing run using the Gemini-North 8-meter telescope in Hawaii, we will be following up several of these candidates.
My warmest congratulations again to the Giants Team! Keep up the fantastic work. After all, we still have a third of RGZ to complete and I am sure more Giant candidates will be discovered in 2017. More information can be found at the Giant team’s RadioTalk Discussion thread.