Radio Galaxy Zoo Talk

What are our VERY BEST 'hourglass sources associated with spirals'?

  • JeanTate by JeanTate

    [42jkb] Two of our scientists (Ray Norris and Minnie Mao) have begun to sift through the sources you have identified and will keep you informed of their progress. Thanks for identifying these for us!

    The Hourglass sources associated with spiral galaxies thread is eight pages long, and mentions hundreds of RGZ objects.

    I've started this thread so ordinary zooites can post what they think are the VERY BEST candidates, say your Top Ten. Not just a bald ARG ID, of course, but also why you think each is a particularly good candidate.

    Got some you think might be good, but don't have a FIRST and/or NVSS contour overlay on a color SDSS image to help you make a judgement? Put in your wish list, as a post to the Suggestions for RGZ Objects to show with detailed FIRST contours overlaid on SDSS images thread! 😃

    What about my own, personal Top Ten? Stay tuned! 😄

    Posted

  • WizardHowl by WizardHowl

    From those I have classified (or else raised discussions on), I have put together a personal top 10. I would definitely put a couple of others ahead of these (antikodon found a couple of really good examples, like ARG00036hs and my all-time favourite the 'sea horse' ARG0002fud). I have sorted my list in to a general order, with those near the top of the list being better candidates but not rating them strictly 1-10 (I also have almost a top 20 that I put together whilst making this list but there were a few examples of disturbed-looking host galaxies there so I could not be so sure about their disk nature, so keeping this to top 10 for the moment).

    http://radiotalk.galaxyzoo.org/#/subjects/ARG00023wq -- overedge triple, SDSS J120301.43+235319.9 Z_sp=0.176
    This gets top spot for the strong core (both in radio and optical) as well as the likelihood of the host being a disk.

    http://radiotalk.galaxyzoo.org/#/subjects/ARG0002g0s -- doublelobe, SDSS J130140.93+183104.9 Z_sp=0.146 The reason I rate this so highly is the overlay of JeanTate that really convinces me this spiral is the host and also because the spiral seems to have undergone an interaction leaving a tidal tail and a small galaxy to its SW.

    http://radiotalk.galaxyzoo.org/#/subjects/ARG0003o7j -- doublelobe, SDSS J022612.45+023307.4 Z_sp=0.145 Here my fondness for dust lanes may be getting the better of me as this has one along its full length.

    http://radiotalk.galaxyzoo.org/#/subjects/ARG0001uiz -- hourglass, SDSS J120339.20+275537.2 Z_ph~0.16-0.18 This galaxy stands out due to the difference in the radio lobes, with one very strong lobe in FIRST but the other only detected by NVSS. It is itself seemingly edge-on, albeit with no signs of a dust lane. It has a few papers on it but I am not sure if it is known/acknowledged as a disk galaxy.

    http://radiotalk.galaxyzoo.org/#/subjects/ARG0001zj8 -- doublelobe, SDSS J122640.22+253855.5 Z_sp=0.134 Again, JeanTate's overlay is helpful here in convincing me this is the host and it does look to me like a face-on spiral but without a very bright AGN.

    http://radiotalk.galaxyzoo.org/#/subjects/ARG0000whi -- bent overedge doublelobe, SDSS J102505.47+443015.4 Z_ph~0.11-0.12 This is the only source in my top 10 that is even slightly bent and the host galaxy strongly resembles that of my number 1, albeit without the bright AGN.

    http://radiotalk.galaxyzoo.org/#/subjects/ARG0002whf -- hourglass, SDSS J080259.73+115709.7 Z_ph~0.13-0.14 Another one where JeanTate's overlay convinces me the disk galaxy is the source, the disk of this edge-on galaxy seems to have a bend in its SW end.

    http://radiotalk.galaxyzoo.org/#/subjects/ARG0000css -- hourglass, SDSS J102733.29+544227.9 Z_ph~0.22-0.29 This one stands out for neigbouring greenish areas that I thought might be a Voorwerp but which could also be regions of star formation. There is a very faint hint of a dust lane down the middle running along its full length SE to NW.

    http://radiotalk.galaxyzoo.org/#/subjects/ARG0001n5b -- overedge doublelobe, SDSS J094103.62+312618.7 Z_ph~0.25 The long and strong jets, of which one has a kink, stand out here, whilst the host galaxy looks edge-on, although it has red colours.

    http://radiotalk.galaxyzoo.org/#/subjects/ARG0000d99 -- hourglassplume, SDSS J152404.92+542805.3 Z_ph~0.2 Here the complexity of the radio emission makes it less clear which galaxy is the host but all the candidates seem to be disk-like, with the host named here closest to being in between the lobes and being aligned such that the lobes would be emerging perpendicular to its disk plane. A spectacular radio source.

    In case you were wondering what I meant by disturbed-looking host galaxies for some of my other 'best' candidates, here is number 11 on my list (see also the weird spectrum!):

    http://radiotalk.galaxyzoo.org/#/subjects/ARG0000hga -- triple, SDSS J123847.46+520302.1 Z_sp=0.221

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  • JeanTate by JeanTate

    I'm going to post my Top Ten in two tranches. Why? Because a) I want to get at least some up ~now, so those in Australia will have at least two sets of Top Tens (sorta) when they get to the office on (their) Monday morning; and b) I need time to properly evaluate and rank ~20 others.

    The four I'm posting now all meet these criteria:

    • the galaxy is the host, as certainly as I think it's possible to be, given the data we currently have;
    • the radio emission - detected in FIRST - clearly extends well beyond the optical boundary of the candidate host;
    • the candidate host is not an elliptical, to a high degree of confidence;
    • I have prepared, and posted, a FIRST-contours-overlaid-on-SDSS image (I will be posting these in the FIRST contours overlaid on SDSS images - our VERY BEST 'doublelobe spirals' thread in due course).

    I intend to attempt three objective tests of the "the candidate host is not an elliptical" criterion, and will edit this post when done. The three tests - which I will elaborate on later (probably a link to an existing post) - are, in shorthand:

    • ellipticity (no true elliptical galaxy is more 'out of round' than E6)
    • radial luminosity profile is more 'exponential' than 'deVaucouleurs
    • inverse concentration ratio is more 'disk' than 'non-disk'

    It is possible that more than six of the good candidates I have yet to evaluate will rate as well as all four here; in that case I'll simply make an arbitrary/random cut.

    The four presented in this post, today, are in order of their ARG ID:

    ARG00012kb: host (z_sp = 0.140) nucleus is also an obvious radio source, with a bridge of radio emission connecting to a complex lobe; morphologically, the host somewhat resembles a late-stage merger, with a prominent dust lane and tidal debris/streams.

    ARG0001t4p: the only one-sided jet/lobe among these four; the z_sp 0.316 host is a red Eos (edge-on spiral), with strong nuclear radio emission.

    ARG0002g0s: strong nuclear radio emission, jet and counter-lobe, from a z_ph ~0.19 host with disturbed morphology (but clearly a disk galaxy, possibly in mid-merger).

    ARG0003a73: my personal fave, a z_ph = 0.45 Eos, likely a Huds (huge distant spiral); while faint, the nuclear radio emission seems real, and the host is well-centered between the lobes.

    UPDATE (Wednesday, 6 August): As expected, when I finished investigating the ~20, I found more than six worthy of being among the Top Ten. Here, then, are my picks. They're broken into two groups, four which are simply outstanding. and two that are merely as good as any of the four above. In ARG ID order:

    ARG0000hga, the 'missing link' that is worthy of being called the "Hanny's Voorwerp" of Radio Galaxy Zoo, a #triple, with a z_sp 0.221 E+A (post-quenched) spectrum, and unambiguous disk morphology (this is WizardHowl's #11 Top Ten)

    ARG00023wq, an obvious #triple with an Eos (edge-on spiral) with a z_sp 0.176 AGN heart (this is Wizard Howl's top pick)

    ARG0002whf, a warped, or interacting, z_ph 0.16 disk galaxy with somewhat asymmetric doublelobes; no obvious AGN, but no spectrum either (also one of WizardHowl's Top Ten)

    J0238+0233 and ARG0003o4w (same host), a very cool spiral with a strong AGN and extensive NVSS doublelobes; sadly, no spectrum (z_ph? unreliable). It was discovered by zooite Tony Wei, and reported in the (now closed) Galaxy Zoo forum; I have not yet been able to find an ARG ID for any FIRST source associated with it. (see update below)

    And the last two, well, I said I'd pick at random, but I didn't 😮 ... with essentially nothing to choose between them, I went for "not in WizardHowl's Top Ten"!

    ARG0000o9l, a.k.a. 4C +48.31, at z_ph 0.465 you'd think it'd be too far away; after all, almost no disk galaxy is big enough to be clearly discerned as such, in SDSS, right? Yet the obvious host is clearly anything but a boring elliptical.

    ARG0001kwr, yet another obvious AGN, confirmed by its spectrum (z_sp 0.125). Morphologically it's not a slam dunk face-on spiral, but I think more detailed investigation will show it to be just that.

    UPDATE (Thursday, 7 August): Thanks to WizardHowl, there is now an ARG ID associated with J0238+0233, the host of cool doublelobes Tony Wei found; ARG0003o4w. I've edited the text above accordingly.

    Posted