Galaxy Zoo Talk

Grav lenses: more a suggestion than a Help question

  • JeanTate by JeanTate

    Gravitational lenses (gravlenses) are apparently one of the most attractive things to many GZ zooites. Despite being incredibly rare, Comments and Discussion threads mentioning possible gravlenses are quite common.

    Yet, as far as I know - if you know otherwise, please point it out!* - there's no stickied Discussion thread which consolidates these, which includes independent searches/images/papers/etc , and so on. I think such a thread would be quite helpful, as would a hashtag group dedicated to just gravlens candidates.

    What do you think? Do you think such a thread and/or such a hashtag group would be helpful? useful?

    *There's a stickied thread devoted to a particular candidate, A possible gravitational lens candidate in SDSS?

    Posted

  • zutopian by zutopian

    Please be informed about following "hashtag collection" by drphilmarshall.:
    Objects Tagged as Lens Candidates
    http://talk.galaxyzoo.org/#/collections/CGZL00000h

    Posted

  • Capella05 by Capella05 moderator

    Actually that tag collection has been managed by myself for the past year. I do forward on intresting candidates to the relevant scientists.

    As with any intresting candidate that gets raised in Talk.

    I prefer if individual threads got raised instead of a single one encompassing all candidates - keeps things clean to people reading the thread and makes it easier for the scientists to get involved.

    Posted

  • JeanTate by JeanTate

    Thanks zutopian, Capella05.

    One limitation of any hashtag group or Collection is that it cannot include any gravlens candidate posted here but sourced outside GZ, such as the one Dolorous Edd recently introduced, unless someone can find an AGZ field in which it appears (not a challenge for the faint of heart!).

    Posted

  • Capella05 by Capella05 moderator in response to JeanTate's comment.

    As I mentioned in my previous post I forward ANY interesting candidates on to the relevant Science teams, irrespective of whether it is part of the current dataset or not.

    As to whether these candidates get followed up with an observation, that is up to the Scientists and the Scientific community at large. As you well know, this can take years - but if the candidate is interesting enough (and these things do get communicated around) then the wait should be a bit shorter.

    I trust this answers your query.

    Posted

  • zutopian by zutopian

    BTW, there is a new GZ blog post, whlch is actually concerning bars, but there is mentioned a "lens candidate", which a summer student serendipitously found during research. According to the scientists it is unlikely a lens.:

    enter image description here

    The galaxy that fooled the computer into thinking it had a redshift of 4.25

    You can see that there is a bright blue smudge in the top left of the galaxy. When I first saw this, I thought it was a lens. It looks like one, and you can just see a small bit of blue on the other side of the galaxy’s core, suggesting a lens even more. According to the experts in the Zooniverse however, this is probably not a lens, as the galaxy does not look massive enough to lens light. Also, the blue curve is well inside the galaxy, instead of being around the outside. Usually, all the mass of the galaxy is needed to lens an object so the light would appear around the edge. The blue curve is most likely an unusual feature of the galaxy itself, which can explain why the reported redshift is so high.

    http://blog.galaxyzoo.org/2015/09/25/galaxy-bars-in-the-summer/

    Posted

  • Capella05 by Capella05 moderator in response to zutopian's comment.

    Some clarification - the 'false candidate' had already been pointed out in GZ Bars Talk over a month ago by @Shocko61 and several of the comments in the blog are from the thread itself. Just FYI 😃

    Thread here : Gz Bars - 472009

    Posted

  • zutopian by zutopian in response to Capella05's comment.

    I posted following comment in the GZ blog post some minutes ago.:

    As far as I know, the image 472009 shows the galaxy, whose GOODS survey ID is GDS J123800+621814! If so, it had been published in following paper as a Lens Candidate!: http://arxiv.org/abs/astro-ph/0309060
    Curiously, in the blog post there is said following.: “According to the experts in the Zooniverse however, this is probably not a lens, as the galaxy does not look massive enough to lens light.”

    If I am right!: To be honest, it is rather astonishing in my opinion, that you didn't check, if it is a known lens candidate!
    #lens #knownlens

    Posted

  • Capella05 by Capella05 moderator in response to zutopian's comment.

    To be honest I don't have the time to look up every single image I come across - anyway I still stand by my opinion.

    I would suggest following up on whether further observations were done, and what was the outcome, than spending time trolling summer students.

    I think Freya wrote a wonderful blog post and she should be commended on that 😃

    (and no, I did not see it or know about it before yesterday)

    Posted

  • zutopian by zutopian in response to zutopian's comment.

    In addition to my previous post.:

    You did follow statement.:

    As I mentioned in my previous post I forward ANY interesting candidates on to the relevant Science teams, (...)

    I guess, that you curiously didn't forward 472009 to the GZ LENS scientists, because in the Zooniverse Talk topic there isn't such a statement! Right?

    Posted

  • ElisabethB by ElisabethB moderator

    What are you implying ? Just asking !

    Posted

  • Capella05 by Capella05 moderator in response to zutopian's comment.

    In reference to the APJ letter that you posted, I cannot find it listed as a strong candidate - and I am still trying to track down if there were any additional observations. At the moment it is looking like it was discarded as a candidate.

    I guess, that you curiously didn't forward 472009 to the GZ LENS scientists, because in the Zooniverse Talk topic there isn't such a statement! Right?

    Can we make this less about me? I had nothing to do with the blog or any of the subsequent research. I just posted a link back to the thread on GZ-Bars.

    I am guessing that you are just trying to kill time while waiting for the eclipse to start. I am prepared to give you leeway for that - but please keep it above board, nice and no mud slinging?

    Cheers 😃

    Posted

  • zutopian by zutopian in response to Capella05's comment.

    In reference to the APJ letter that you posted, I cannot find it listed as a strong candidate - and I am still trying to track down if there were any additional observations. At the moment it is looking like it was discarded as a candidate.

    In the abstract there is given following statement.:

    We present our six most promising lens candidates, as well as our full list of candidates.

    http://arxiv.org/abs/astro-ph/0309060

    The galaxy isn't one of the six most promising ones, whose images are shown in the paper, but it is listed in the above mentioned list (link below), which has the title "Strong Lens Candidates in GOODS Fields".:
    http://www.stsci.edu/science/goods/lensing/Lenscands/lenscands.html

    In conclusion, it is a strong lens candidate according to below paper!:

    Strong Gravitational Lens Candidates in the GOODS ACS Fields
    Authors: C. D. Fassnacht (1), L. A. Moustakas (2), S. Casertano (2), H. C. Ferguson (2), R. A. Lucas (2), Y. Park (2 and 3) ((1) UC Davis, (2) STScI, (3) JHU)
    (Submitted on 2 Sep 2003)
    http://arxiv.org/abs/astro-ph/0309060

    Posted

  • zutopian by zutopian

    @Capella05

    Could you please post an update in the Zooniverse Talk discussion about 472009? I mean a post, where you inform about the blog post and my comment in the blog post!

    PS: I haven't done any posts in Zooniverse Talk so far and I haven't the intention to start using that forum.

    Posted

  • Capella05 by Capella05 moderator

    Sorry don't want to nit pick but that is a letter not a paper and without any subsequent data to substantiate it, it still looks doubtful as a candidate. The First author has gone on to have quite a few papers published, so if this subject was interesting enough it would have been revisited in the preceding 12 years.

    Posted

  • Capella05 by Capella05 moderator in response to zutopian's comment.

    I will do so, but perhaps you should also add a appendum to your blog comment?

    Posted

  • zutopian by zutopian in response to Capella05's comment.

    I will do so, but perhaps you should also add a appendum to your blog comment?

    You wrote "appendum", but I guess that you actually mean "addendum".
    Sorry, but I don't know, what your comment means. What statement should I add to my blog comment?

    Posted

  • Capella05 by Capella05 moderator in response to zutopian's comment.

    What we have been discussing here? Your blog comment is misleading.

    Posted

  • zutopian by zutopian in response to Capella05's comment.

    What we have been discussing here? Your blog comment is misleading.

    I don't agree, that my blog comment is misleading! I think, that one of the GZ scientists should reply to my blog comment! Besides I think, that one of the GZ scientists should add an addendum at the end of the blog post!

    Posted

  • zutopian by zutopian in response to Capella05's comment.

    The First author has gone on to have quite a few papers published, so if this subject was interesting enough it would have been revisited in the preceding 12 years.

    BTW, there are various papers, where Mr Fassnacht and GZ scientist Dr. Phil Marshall are both listed as authors! So maybe Phil Marshall could find out, why this subject hasn't been revisted so far.

    Posted

  • Capella05 by Capella05 moderator

    At this point I am going to have to reiterate a previous question posted to you - what exactly are you trying to imply?

    Are you trying to embarrass a student who wrote an innocent blog post about her experiences as a intern at the Zooniverse? Are you implying that she did not have adequate supervision? or that her blog wasn't double and triple checked to the standards that could be expected of a peer reviewed paper? Seriously?

    Or perhaps the blog has nothing to do with it, and you are just attempting to create an argument with me. Sorry, but I will not be complicit to that. Hope you get the answers you are looking for.

    Posted

  • zutopian by zutopian in response to Capella05's comment.

    Are you trying to embarrass a student who wrote an innocent blog post about her experiences as a intern at the Zooniverse? Are you implying that she did not have adequate supervision? or that her blog wasn't double and triple checked to the standards that could be expected of a peer reviewed paper? Seriously?

    It don't criticize the summer student! The summer student is new! Besides s/he actually did reseach concerning bars! Concerning the arc s/he just cited following statement by others.: "According to the experts in the Zooniverse however, this is probably not a lens, as the galaxy does not look massive enough to lens light."

    I don't mean standards of peer reviewed papers, but standards of science journalism! An editor-in-chief checks an article before publication, as far as I know. I think, that in this case someone -the GZ scientists and/or you- should have checked, if this galaxy has a "lens" reference! The part about the arc is inaccurate in my opinion. BTW, DZM worked as a journalist (but not for science), as far as I know. He might want to comment!

    Concerning your following statement in another post.:

    As I mentioned in my previous post I forward ANY interesting candidates on to the relevant Science teams, (...)

    I guess, that this one wasn't interesting enough for YOU to forward to the lens science team! "Interesting" is somehow subjective in my opinion. It would have been actually worth to inform the lens science team about the galaxy IMHO, especially because you didn't check the references.If you had checked, it wouldn't have been necessary to forward. I think, that the scientists should actually decide, if something is interesting or not. Maybe the scientists don't agree with my point of view! I just say my opinion- for what it is worth!

    Posted

  • Capella05 by Capella05 moderator

    I guess, that this one wasn't interesting enough for YOU to forward to the lens science team! "Interesting" is somehow subjective in my opinion. It would have been actually worth to inform the lens science team about this galaxy in my opinion, especially because you didn't check the references.If you had checked, it wouldn't have been necessary to forward. I think, that the scientists should actually decide, if something is interesting or not. Maybe the scientists don't agree with my point of view! I just say my opinion- for what it is worth!

    So it is about me - I have no idea what I have done to offend you so much. I will let others take it from here.

    Posted

  • Capella05 by Capella05 moderator

    Thread locked - the other Moderators and Scientist's can review / discuss / unlock from here. I just have an moon eclipse to get to.

    Posted