The Naked Scientists
  • Login
  • Register
  • Podcasts
      • The Naked Scientists
      • eLife
      • Naked Genetics
      • Naked Astronomy
      • In short
      • Naked Neuroscience
      • Ask! The Naked Scientists
      • Question of the Week
      • Archive
      • Video
      • SUBSCRIBE to our Podcasts
  • Articles
      • Science News
      • Features
      • Interviews
      • Answers to Science Questions
  • Get Naked
      • Donate
      • Do an Experiment
      • Science Forum
      • Ask a Question
  • About
      • Meet the team
      • Our Sponsors
      • Site Map
      • Contact us

User menu

  • Login
  • Register
  • Home
  • Help
  • Search
  • Tags
  • Member Map
  • Recent Topics
  • Login
  • Register
  1. Naked Science Forum
  2. Non Life Sciences
  3. Physics, Astronomy & Cosmology
  4. lensing on "galaxy zoo"
« previous next »
  • Print
Pages: [1]   Go Down

lensing on "galaxy zoo"

  • 1 Replies
  • 2306 Views
  • 0 Tags

0 Members and 1 Guest are viewing this topic.

Offline Pecos_Bill (OP)

  • Sr. Member
  • ****
  • 334
  • Activity:
    0%
    • View Profile
lensing on "galaxy zoo"
« on: 04/05/2014 03:00:48 »
I have turned from computer solitare to classifying photos of galaxies on "galaxy zoo".

There is a gismo to say that a photo contains evidence of lensing of light -- in my opinion..

I often so mark photos which show 2, 3 or even  4 symmetrical and similar instances around a central object.

Is that plausibly lensing as I have seen in "Einsteins cross" or should it just be an arc near the image -- as described on the gismo/choice?
Logged
 



Offline evan_au

  • Global Moderator
  • Naked Science Forum GOD!
  • ********
  • 9190
  • Activity:
    73.5%
  • Thanked: 917 times
    • View Profile
Re: lensing on "galaxy zoo"
« Reply #1 on: 04/05/2014 11:38:43 »
It is possible for gravitational lensing to distort a very distant (point-like) object into several images which also are point-like.

But gravitational lenses are not like well-designed camera lenses - they tend to distort extended (closer) objects, often into arcs.

It is conceivable that an isolated elliptical galaxy (if it had a spherical dark matter halo) could approximate a camera lens; but galaxies tend to occur in clusters, so the light you see from a distant object is likely to take different paths through a cluster of overlapping gravitational lenses. This would cause significant distortion of the distant galaxy image.

It may be possible to see if the distorted fragments you see surrounding a galaxy are images of the same distant object by looking at the red-shift of each fragment. But this requires a lot more information than you get with the survey images on Galaxy Zoo. Measuring the red shift requires a lot more light (ie much longer exposures on a bigger telescope), so it is impractical at present.

If you mark potential lensing (and this is a consensus view of a number of members who review the same image), investigators can come back later for a closer look - for example to try and analyse the mass distribution of the intermediate object (including any dark matter halo).
Logged
 



  • Print
Pages: [1]   Go Up
« previous next »
Tags:
 

Similar topics (5)

Are the spiral arms of a spiral galaxy visible?

Started by hihelloBoard Physics, Astronomy & Cosmology

Replies: 4
Views: 4029
Last post 01/11/2009 01:57:34
by GlentoranMark
The universe is 13.8b years old, yet we've seen a galaxy 13.4b light years away?

Started by nudephilBoard Physics, Astronomy & Cosmology

Replies: 9
Views: 347
Last post 01/02/2021 21:42:12
by Halc
Does dark energy impact gravitationally bound systems like galaxy clusters?

Started by George Voulgaris Board Physics, Astronomy & Cosmology

Replies: 2
Views: 3225
Last post 11/11/2010 15:24:39
by imatfaal
Would dark matter ripples from galaxy collision interfere through a double slit?

Started by fthomposonBoard Physics, Astronomy & Cosmology

Replies: 4
Views: 2029
Last post 19/09/2017 16:44:49
by fthomposon
Which is colder: vacuum outer space or core of super-galaxy?

Started by jsaldea12Board General Science

Replies: 23
Views: 2288
Last post 06/04/2019 00:16:35
by Kryptid
There was an error while thanking
Thanking...
  • SMF 2.0.15 | SMF © 2017, Simple Machines
    Privacy Policy
    SMFAds for Free Forums
  • Naked Science Forum ©

Page created in 0.15 seconds with 38 queries.

  • Podcasts
  • Articles
  • Get Naked
  • About
  • Contact us
  • Advertise
  • Privacy Policy
  • Subscribe to newsletter
  • We love feedback

Follow us

cambridge_logo_footer.png

©The Naked Scientists® 2000–2017 | The Naked Scientists® and Naked Science® are registered trademarks created by Dr Chris Smith. Information presented on this website is the opinion of the individual contributors and does not reflect the general views of the administrators, editors, moderators, sponsors, Cambridge University or the public at large.