Space Warps Talk

READ THIS FIRST ! Guide to Information on SpaceWarps Talk

  • Budgieye by Budgieye moderator

    Many of your questions are answered here.


    Look at the Spotter's Guide too http://spacewarps.org/#/guide. There is another spotter's guide, the quick view reminder that you see on the right when you are classifying.


    Why does the SpaceWarps project exist?

    You are trying to see some of the most distant objects in the Universe, magnified by a somewhat closer galaxy 😃

    Using that information we can learn more about dark matter, and the "weight" of the universe.

    About 2/3 of the matter in the Universe is Dark Matter. The rest is matter (stars and people), light photons, and neutrinos. How can we understand out Universe if we don't know what most of it is made of?

    When we study gravitational lenses, we can at least detect where it is, and how much of it there is. Dark Matter has gravity, so we can detect it by measure how much space is bent (ie warped) by its gravity . We measure it by modeling the increased distance light must take when it dips into a gravity "hole"

    What is Dark Matter? see the article in Wikipedia.

    So scientists must find gravitional lenses.

    There are millions of images of galaxies to be looked at.
    Computers can help us by searching for gravitational lenses, but they only find the easy ones.
    Has the computer search missed some lenses?
    People are better at seeing lensed galaxies than computers.
    So people are doing an independent search for lenses.
    If the computer program has missed some, the programming can be improved
    There are millions of galaxies still out there, and we will need teamwork between computers and people to find the lenses around them.

    Why does SpaceWarps Talk exist?
    Talk is a forum where the people can discuss what they see, and learn how to find out more about galaxies and gravitational lenses.
    It is not fair that computers should have all the fun.


    SpaceWarps Talk guide

    Trying to find information on lenses or Talk?

    Either the information is here, or there is a pointer to a post that explains it.

    Categories are:

    1 WOW! WHAT'S THAT? Artifacts- "supernova", star spikes, satellites, cosmic ray hits, meteors, "black holes"

    2 GOOD LENS CANDIDATES How many classifications?

    3 USING CLASSIFICATION - bugs and improvements

    4 USING TALK - bugs and improvements OPEN IN TOOLS - The dashboard

    5 SCIENTISTS AND MODERATORS and SCIENTIST'S BLOGS

    6 LENS TOY - playing around with a lens simulator,also Spaghetti Lens Modeler

    7 LENS EXPLANATIONS

    8 Information about the images we are looking at: CFHTLS (Canada-France-Hawaii Telescope Legacy Survey),

    9 FINDING MORE INFORMATION - NED, SDSS, and other lens surveys,

    11 ** THESE ARE NOT LENSES** -examples of what you might mistake for lenses.

    Posted

  • Budgieye by Budgieye moderator

    1. WOW WHAT'S THAT?

    Many strange objects are identified in the Spotter's Guide http://spacewarps.org/#/guide

    Stars and Star Spikes

    The brighter stars make a big bright image with spikes, because the CCD sensors get overloaded.

    They are not supernova or exploding stars.


    STAR

    star

    ASW00001ik

    Bright stars have spikes caused by the 4 wires holding the secondary mirror in place. Dim stars are round, with no spikes.

    Optical artifacts- some of the stars have green blips in their top right corner. This is caused by poor alignment of images when they are stacked.


    BRIGHT STAR

    star

    ASW0000w1e

    Here is a very bright star, with spikes and diffraction rings.


    SATELLITE AND COSMIC RAYS

    satellite

    ASW0001s4c

    The blue streak is a satellite that went by during the blue filter exposure.

    The bright green dot at 12, halfway to the edge is a cosmic ray hit. It is small with sharp edges. It hit the ccd camera during the green filter exposure. There are others in green or blue on the left. Most cosmic rays are cleaned out out the images, but the software misses some. They are often found at the edges of the photos, or in the middle of a galaxy where the software is unsure whether it is a cosmic ray or something real, so doesn't remove it.

    The white star at the center has a chance alignment with a red star

    The red disc at the top is a red star. Galaxies are more diffuse than stars. There is an orange galaxy near the center.


    ASTEROIDS

    asteroid

    ASW0000vhx

    Asteroids leave discs of green, red or blue. They may move during the 30 minute exposures of green, red and blue.

    The white star in the center has a chance alignment with a small red star.

    The blue ring object at 6 is a blue star. The center of the star is overexposed, and turns white. There appears to be a cosmic ray hit on it that wasn't cleared away.


    QUASARS

    enter image description here

    ASW0001rcc possibly a quasar, not lensed.

    see Thick blue ring, it's just too perfect http://talk.spacewarps.org/#/boards/BSW0000004/discussions/DSW00007j7

    gravitational lens candidates in the XMM-LSS/CFHTLS common field - arXiv:1307.2254 http://talk.spacewarps.org/#/boards/BSW0000004/discussions/DSW00007l0 (images of quasars)

    images of quasars Quasar Questions http://talk.spacewarps.org/#/boards/BSW0000004/discussions/DSW0000bvn


    BLACK HOLES are not important for lens research. #blackhole #blackholes #black_hole #black_holes

    Black holes make up only a small fraction of a galaxy's mass. Most of the mass of a galaxy is Dark Matter. We can't see Dark Matter, and don't know what it is, though it is probably some sort of non-interacting subatomic particle, but it makes up most of the "weight" of a galaxy.

    WE CAN'T SEE BLACK HOLES IN OUR IMAGES

    Not because they are black, as most of them are surrounded by glowing hot gas, but because they are too small. They are less than the size of a single pixel on our page. Any round black things that you see on the page are usually artifacts of the computer clean-up process, where a messy cosmic ray hit is removed. Objects arranged in a circle or symmetrical arrangement around a dark area may be just a chance alignment.

    see post Can a massive black hole cause lensing?


    For more examples of artifacts, see this thread in Galaxy Zoo forum
    WOW WHAT'S THAT? LOOK HERE FIRST! by Jules

    Posted

  • Budgieye by Budgieye moderator

    Number of classifications : Automated Search Systems

    May 8, 2013 The Start. We've got 400,000 images, and need about 10 views per image to take care of the uncertainty in each classification-drphilmarshall,

    http://talk.spacewarps.org/#/boards/BSW0000002/discussions/DSW0000171

    So, 4,000,000 to do
    May 10 one million done
    May 20 two million done

    EDIT

    June 20 - About half of the images are being retired, since nobody clicked on them after 10 viewings.
    There are about 1,500 candidates of varying degrees of reliability. Some of the good ones are discussed in Talk.
    There have been 8,000 citizen scientists participating in SpaceWarps, and 40% of them participate in Talk.
    Citizen Scientist get marked on how we perform on the #sims. Only 92% of the sims are actually visible, and 8% are below threshold. So remember to mark the arcs and quasar points, not the center of the galaxy! (I don't think I would like to know my score. When I start missing #buriedrings, I know it is time to stop.)

    Some lens hopefuls are here:

    Where do I go to see the best stuff?

    Scientist write blogs about the progress of the research.
    The SpaceWarps blogs are in the

    Space Warps A Zooniverse Project Blog (formerly Lens Zoo) website

    Estimated percentage of lensed galaxy finds

    Space Warps Update

    Some good lens candidate found!


    enter image description here

    http://talk.spacewarps.org/#/subjects/ASW0004dv8 posted by rotex


    enter image description here

    http://talk.spacewarps.org/#/subjects/ASW0003dq7 posted by bermeister


    enter image description here

    http://talk.spacewarps.org/#/subjects/ASW0000fzv posted by Damon22


    enter image description here

    http://talk.spacewarps.org/#/subjects/ASW0003r2w posted by Tashipoo

    Posted

  • Budgieye by Budgieye moderator

    1. USING CLASSIFICATION - bugs and improvements

    Keyboard reminders

    Use Ctrl+ and Ctrl- to make your images larger and smaller (command+ and command-)

    Press F11 to make your screen bigger by getting rid of the address bars at the top, And more importantly, F11 gets them back again!

    If you click on a link, possibly the link will replace the page you are looking at, and you will have to go back and find your original page.

    Open a new tab. If you press Ctrl when you click on a link, the link will open in a new tab, and you won't lose your original tab.

    Open a new window. If you press Shift when you click on a link, the link will open in a new window.

    Refresh your page ocassionally by using F5 or the refresh button, or your computer gets confused.


    There is the useful short spotters guide on the right.But if it is obscuring your image, you can slide it out of the way by clicking on the "spotters guide" tab. There is another and longer Spotters Guide on the left http://spacewarps.org/#/guide

    The square box symbol is the dashboard. You can use the dashboard to magnify the image, move it around, make it bluer to reveal blue lenses hidden near the nucleus in white galaxies, or make the screen brighter.

    Did you miss a lens? Just click on Profile and there you'll see the last 10 images you've seen. You cannot mark anything there, but clicking on the image will bring you to Talk and then you can comment on it in Talk

    Which Browser?

    SpaceWarps probably works best with Chrome, obtained free from Google.

    Firefox 19 is the minimum Firefox brower

    IE (Internet Explorer) doesn't have the tools needed when Dashboard is being used. So you can't magnify or enhance the image when Internet Explorer is your browser.

    If you are having trouble seeing any images, post on
    Talk :FAQ Questions: Which browsers are supported?

    http://talk.spacewarps.org/#/boards/BSW0000001/discussions/DSW0000003

    and mention which versions of Windows or Apple, and your browser you are using.

    Posted

  • Budgieye by Budgieye moderator

    4. Using Talk
    Did you miss a lens in classification?

    Go into your profile in classification, and the image should be there in Recents.

    You can post a picture in Talk by right clicking on it, select copy image location,

    then select the picture from the icons, the square thing that looks like a picture frame,
    you get a pop-up box with Insert Image http://

    Paste the image in the box (the shaded http:// will go away)
    and you get this statement

    ![example picture](http://spacewarps.org/subjects/standard/5183f151e4bb21021900b084 .png) and you get

    example picture

    http://talk.spacewarps.org/#/subjects/ASW0000yv8

    If you see a picture on the internet that you would like to post, try right clicking on it, then paste the Http.... as described before.

    If you have a picture on your computer that you would like to post, you will need to post it on the internet eg. Flickr, Photobucket, etc.

    When you post an image, please post lots of information with it, especially the ID

    ASW0000yv8

    Use informative words and hashtags

    Not :

    lens? which does not stimulate discussion

    But:

    orange galaxy with nearly complete blue arc, top left corner #arc

    In some images the lens may not be so obvious, and people get discouraged looking for it.

    We can describe the location of an object by pretending that the image is a clock. eg

    The blue arc is around an orange galaxy, at 11:30, near the edge.

    Arcs and quasar points are usually within 10" of a massive galaxy. Less massive galaxies will have their lenses closer to the center of mass. The images are 60" wide.

    The main blue arc is 4" from the center of the galaxy. The arc may extent to 10" away.

    If you want to use N S E and W, please remember that E and W are reversed, since you are "facing south and looking up the sky", not "facing north and looking down at the ground" as in terrestrial maps.

    The lensed galaxy is in the NNE


    The Collect button

    Here you go 😃 - Making your own collection in 5 easy steps (copied from something by ElisabethB)

    If you classifying images over at Spacewarps there are two places where you can choose the image you want to collect.

    On the 'Classify' page, select the 'Talk' button (the speech bubble on the dashboard). A new window will then open in Talk. If you have already classified the image, go to 'Profile' and select your chosen image. You will then be navigated to Talk.
    On the image in 'Talk' in the left hand corner, superimposed over the image, is the 'Collect' button. Click on it!
    The collections menu will now appear, and you have the option of adding the image to one of your default collections (e.g. My Collection) or creating a new collection.

    Click on 'New Collection'.
    Give your new collection a name and description and save.

    To view your collection go to your 'Profile' (Top Toolbar in Talk) and scroll down to the bottom of the page. You will now be able to select a collection and view all the images in it 😃

    Remember you do not need to create a new collection for every image you can add them into your existing collections!


    Open in Tools / Dashboard

    http://tools.zooniverse.org/#/dashboards/spacewarp

    Digging Deeper with the Dashboard by drphilmarshall http://blog.spacewarps.org/2013/10/01/digging-deeper-with-the-dashboard/

    Examples of using Dashboard / Open in Tools http://talk.spacewarps.org/#/boards/BSW0000004/discussions/DSW0000ckp
    Summary
    Click on Open in tools in the top right corner, then click on u to see the object in violet light.
    Slide the dark and contrast buttons until you see an image.
    Click copy, then save the address in the top left corner if you want to post the link.
    (if someone knows how to post the image, please tell me!)

    blue arc lenses from star-forming galaxies have lots of violet light, you will see bright arcs in violet light.
    red arc lenses are from inactive galaxies, nothing to see in violet light.
    double and quad points from blue quasars (z=1) they have violet light, so look in u band
    double and quad points from green, orange, yellow or red quasars (z of 4) don't have violet light, nothing in u band


    What browser are you using ? Internet Explorer (IE) is not compatible with SpaceWarps. IE is missing some applications that is required by SpaceWarpl. So switching to Chrome, Firefox or Safari would be a good thing. Google Chrome is free to download off the internet.


    FOR BBC STARGAZING LIVE 2014 - the dashboard consists of only 3 wavelengths of infrared light


    You can post a link
    by clicking on the icon that looks like an image of the world

    An example in Talk

    Look at this one

    or outside Talk

    [The lens is already known: here is the link to the scientific article] (http://iopscience.iop.org/0004-637X/749/1/38/pdf)

    The lens is already known: here is the link to the scientific article

    If you want to edit your post, and EDIT seems locked, refresh your screen with F5 or the circular arrow on your address bar.

    If Talk seems unresponsive at any time, try refreshing your screen.

    If someone has gone to a lot of effort to answer your question, please thank them.

    If you see a post with inappropriate content, or advertising, please click on the Report button, and a moderator will look at the post.


    To make posting more friendly.

    Well, some are working. Remove the space

    : ) 😃 smile

    ; ) 😉 wink

    : ) 😄 cheesy grin

    ; ) ;D big grin

    angry >: ( 😠

    : O 😮 shocked

    8 ) 8) cool

    : S :S confused

    8- ) 😎 roll eyes

    : P 😛 tongue

    😒 embarrassed (I can't get this one to work)

    :- X :-X lips sealed

    :- \ :-\ undecided

    :- * 😗 kiss

    :' ( 😢 cry

    Sending a personal message (pm)
    You can send messages by going into Profile, and Compose Message.
    You know you have received a message when the envelope icon in the top right corner lights up and has a number beside it. Click on the icon to open your mailbox.
    Unread messages will have a blue dot beside them. The computer thinks that you haven't read them until you actually click on each message to open them. Then the blue dot beside the message will go away, and the envelope icon will go dark.

    Posted

  • Budgieye by Budgieye moderator

    5 SCIENTISTS AND MODERATORS and Scientist's Blogs

    These people take care of the website, and answer most of the questions.
    Forum website are mostly run by volunteers who want to learn more about the galaxies and lenses after the work of classification is done. Amateurs (ie those who do science for the love of it) in Galaxy Zoo projects are often called Zooites

    We take pride in a polite, cheerful and scientific forum.

    Capella05 moderator (volunteer)

    ElisabethB moderator (volunteer)

    Budgieye moderator (volunteer)

    Thomas J moderator (volunteer)


    drphilmarshall scientist

    anupreeta scientist and moderator

    Aprajita moderator scientist

    Tom Collett scientist

    psaha scientist

    rafael_kueng scientist

    jgeach scientist

    surhudm scientist

    cecilefaure scientist

    arfon admin (leaving at end of September, 2013) 😢

    Have I missed anyone?

    Some of the posts in Talk are done by visiting scientists, who are kindly helping out in the forum. Some are done by experienced Zooites who have posted in Galaxy Zoo forum for the last 5 years.

    Scientist write blogs about the progress of the research.
    The SpaceWarps blogs are in the

    Space Warps A Zooniverse Project Blog (formerly Lens Zoo) website

    April 2, 2013 A New Name, Debugging, and Some Mind Games by Phil Marshall. The project was at first called Lens Zoo, but ThomasJ pointed out that people would be asking "Who is Len?". So a more exciting and informative name was chosen.

    May 7, 2013 Space Warps CFHTLS by Phil Marshall

    May 8, 2013 New Project: Join the Search for ‘Space Warps’ by ttfnrob

    May 9, 2013 Engage! by Phil Marshall

    May 15, 2013 Space Warps Update by Aprajita

    May 27 2013 Sim City by Anupreeta, Surhud and Phil Marshall. How sims are made and why they are important.

    June 14, 2013 It's good to talk by Aprajita. retirement of images, marking of lenses,

    June 18, 2013 What happens to your markers? A look inside the SpaceWarps analysis pipeline halfway through, and 1,500 interesting images found.

    Phil Marshall says : June 24, 2013 at 6:49 pm
    As images are retired, new ones are brought in to the system; this will keep going until either we complete the project, or we decide to focus on a particular subset of images (in which case we’ll activate those ones by hand). If you, individually, stops seeing images, it’s because you have seen all the images that are currently active (the system is set up not to ever show you the same image twice). When that happens, I guess it’s time to spend some time in Talk while you wait for rest of the collaboration to retire some images!

    August 15, 2013 by aprajita , some of the discovered lenses

    Oct 1, 2013 Digging Deeper with the Dashboard by drphilmarshall http://blog.spacewarps.org/2013/10/01/digging-deeper-with-the-dashboard/ The lensed features are usually blue – so brightest in the g-band

    Nov 22, 2013 by Dr Phil Marshall Coming soon: narrowing down the candidate list with Space Warps Refine http://blog.spacewarps.org/2013/11/22/coming-soon-narrowing-down-the-candidate-list-with-space-warps-refine/ sorting out the best 3,300 lenses

    Dec 19 2013 by Dr Phil Marshall http://blog.spacewarps.org/2013/12/19/seasons-greetings-from-space-warps-some-refined-lenses-and-a-big-thank-you/

    Jan 7 2014 by Dr Phil Marshall http://blog.spacewarps.org/2014/01/07/new-year-new-data-hunting-for-lenses-in-the-infrared-with-vics82/

    40,000 images from the survey, VICS82 stands for “VISTA-CFHT Stripe 82″, and is the largest near-infrared imaging survey of its kind, mapping nearly 200 square degrees of the Sloan Digital Sky Survey ‘Stripe 82′ – a narrow strip of sky that is the deepest part of the SDSS. VICS82 is using two 4-m class telescopes fitted with large-format near-infrared cameras: the Canada-France-Hawaii Telescope (atop Mauna Kea in Hawaii) and the VISTA survey telescope in the Chilean Atacama.

    Blog; Seasons Greetings from Space Warps: Some Refined Lenses, and a Big Thank You! Phil, Aprajita and Anupreeta Dec 19, 2013 http://blog.spacewarps.org/2013/12/19/seasons-greetings-from-space-warps-some-refined-lenses-and-a-big-thank-you/ "Well, Space Warps Refine has been running for just over a week, and it’s had a fantastic response from you all. THANK YOU! With over 140,000 classifications of the 3679 images, we have very good data on almost all of them – and some exciting new lens candidates are popping out of the pipeline!"

    Blog: It’s good to Talk! Why we need to hear from you to find Space Warps by Aprajita June 14, 2013
    by Aprajita http://blog.spacewarps.org/2013/06/14/its-good-to-talk/ "Most excitingly, some of you have started discussing a few lens candidates that we think have been missed by the algorithms"

    Blog: X marks the spot: new gravitational lens candidates from Space Warps August 15, 2013 by Aprajita http://blog.spacewarps.org/2013/08/15/x-marks-the-spot-new-gravitational-lens-candidates-from-space-warps/

    Blog: Trailer: Results from CFHTLS April 23, 2015 by Phil Marshall http://blog.spacewarps.org/2015/04/23/trailer-results-from-cfhtls/ " We’re currently in the process of posting two papers from the CFHTLS project, but one (that describes the system) is stuck in the works for being too massive. (Insert gravitational lensing joke here.)" 😃 !!!

    Blog: Space Warps: New Candidate Gravitational Lenses in the CFHTLS! April 24, 2015 by Aprajita " It’s good news: in addition to finding 80 previously published candidate gravitational lenses, you helped discover 28 new candidate gravitational lenses (and another 30 objects that might turn out be lenses). Nice work, people!"

    Posted

  • Budgieye by Budgieye moderator

    6 Lens Modeling


    LENS TOY** - playing around with a lens simulator, this is a simple model

    http://slowe.github.io/LensToy/

    Developed by LensToy is by Stuart Lowe, Aprajita and drphilmarshall.

    Absolutely essential for understanding lenses that make arcs and circles. We can still see the lensed galaxy, even though it directly behind the lensing galaxy.

    [at the moment, Lens Toy doesn't work for me when I use Chrome, though it works using Firefox]


    Spaghetti lens modeler http://mite.physik.uzh.ch/lmt.html

    tutorial http://mite.physik.uzh.ch/tutorial/videos/all/tuto_player.html

    (spaghettti lens modeler is best used with Chrome, instead of Internet Explorer, Firefox or Safari)

    post results on Modeled Candidates http://talk.spacewarps.org/#/boards/BSW0000006/discussions/DSW00004zu

    Have fun!


    Examples on how to do models, by psaha (scientist), third post down in SpaghettiLens - Updates, Bug fixes etc...

    http://talk.spacewarps.org/#/boards/BSW0000006/discussions/DSW00007j4

    Posted

  • Budgieye by Budgieye moderator

    7 LENS EXPLANATIONS

    Do you want to learn more how gravitational lenses work? Remember, in SpaceWarps, we are looking at big lenses, where large areas of space is warped by large distant galaxies. We are not looking at weak lenses caused by nearby small black holes, as illustrated in this video Lensing by a Black Hole

    In the main SpaceWarps Classification website Science there is the video of a lensed quasar Space Warps in Action

    Use Lens Toy - by Gumbosea

    In SpaceWarps Talk Easy Explanation of Gravitational Lenses - by Budgieye

    What is Gravitational Lensing? by CFHTLenS, the organisation who supplies us with images.

    What is Dark Matter? by CFHTLenS

    In You Tube,

    What is gravitational lensing? with our own Phil Marshall doing the wineglass lens trick.


    The original Galaxy Zoo Forum, put together by volunteer posters, has lots of relevant information

    Zooite Guide to Gravitational Lenses by Budgieye. The images are from SDSS. In SpaceWarps the images are slightly better and smaller lenses will be easier to see, but the idea is much the same.

    Possible strong gravitational lenses thread. Hundreds of pages of images from SDSS, and the discussions: is it or isn't it? Many posts by ElisabethB, gumbosea, Capella05 ,joinpep and many others.

    Colours of Galaxies in SDSS : Redshift chart by Budgieye. You can make an educated guess on how distant an object is and what type of galaxy it is by looking at its colour, size and shape. At increasingly higher redshifts, the colours of quasars get redshifted., and the light from galaxies gets redshifted until they are undetectable by our optical telescopes.. Remember that lensing doesn't change the colour of the lensed galaxy, they are still the same colour, but brighter and distorted.

    Zooite Guide to SDSS Spectra by Budgieye Lots of pictures of stars and galaxies, and how you can interpret what they are by their colours and shape. Once again, this is for SDSS data, but the colours are similar enough to recognize what category of stars and galaxies you are looking at.

    QUASARS. What they are and how to find them. by ThomasJ. A useful review of quasars.

    Posted

  • Budgieye by Budgieye moderator

    8 **Information about the images we are looking at:


    For BBC Stargazing Live 2014, we used 40,000 images from the VICS82 survey

    In this project we are asking you to look for gravitational lenses in
    infrared images, where the most distant galaxies in the Universe can
    be seen. The survey images were taken using three filters (i, J and
    Ks) on two different telescopes (CFHT and VISTA), and combined into a
    color composite...Each image is known to contain, at the center of the field, an object that could either be a lens, or a source that >would be interesting if it was lensed.

    Jan 7 2014 by Dr Phil Marshall http://blog.spacewarps.org/2014/01/07/new-year-new-data-hunting-for-lenses-in-the-infrared-with-vics82/

    40,000 images from the survey, VICS82 stands for “VISTA-CFHT Stripe 82″, and is the largest near-infrared imaging survey of its kind, mapping nearly 200 square degrees of the Sloan Digital Sky Survey ‘Stripe 82′ – a narrow strip of sky that is the deepest part of the SDSS. VICS82 is using two 4-m class telescopes fitted with large-format near-infrared cameras: the Canada-France-Hawaii Telescope (atop Mauna Kea in Hawaii) and the VISTA survey telescope in the Chilean Atacama.


    In 2013
    CFHTLS** (Canada-France-Hawaii Telescope Legacy Survey)

    Jean-Paul Kneib, from the Strong Lenses in the Legacy Survey (SL2S) project was interviewed in this blog
    SpaceWarps CFHTLS

    Over 10 million galaxies were looked at using computer search programs and 127 lenses were found, most by the computer search and some by a lucky observation by a person.

    Introduction to the Canada France Hawaii Telescope Lens Survey.
    http://www.cfhtlens.org/public/canada-france-hawaii-lensing-survey

    The CFHTLS-Strong Lensing Legacy Survey (SL2S): Investigating the group-scale lenses with the SARCS sample.
    http://iopscience.iop.org/0004-637X/749/1/38/pdf/0004-637X_749_1_38.pdf The survey contains 127 lens candidates
    .There are images of the 127 lens candidates in this article. 😃

    SL2S-Arcs summary table from the T0006 release

    A search for edge-on galaxy lenses in the CFHT Legacy Survey 17 lens candidates with images
    http://arxiv.org/pdf/1001.4336.pdf

    A new window of exploration in the Mass Spectrum: Strong lensing by galaxy groups in the SL2S . no pictures http://arxiv.org/pdf/0812.1033.pdf

    Dark matter distribution in galaxy groups from combined strong lensing and dynamics analysis. 2 pictures
    http://iopscience.iop.org/0004-637X/714/2/1355/pdf/0004-637X_714_2_1355.pdf

    The CFHTLS Strong Lensing Legacy Survey:
    I. Survey overview and T0002 release sample 2008 some inverted images.
    http://arxiv.org/pdf/astro-ph/0610362.pdf

    Gravitational lensing in the supernova legacy survey (SNLS) 2010. some inverted images
    http://arxiv.org/pdf/1002.1249.pdf

    List of selected publications of all areas of research in CFHT, including weak lensing, galaxy morphology, quasar search, supernova search, stars and Kuiper belt objects.
    http://www.cfht.hawaii.edu/Science/CFHLS/cfhtlspublications.html

    Now the sky images have been released to the public. SpaceWarps will see if they missed any.


    Hawaii Hawaii 13,700 ft or 4,200m

    The telescope takes images that have less detail than Hubble Space Telescope ( used in Hubble Zoo ), and more detail than SDSS (Sloan Digital Sky Survey) used in Galaxy Zoo.

    The telescope covers more sky than Hubble, and less sky than SDSS.


    The footprint Where are images coming from
    The images come from 4 areas of the sky in the CFHTLS Deep survey, so from D1, D2, D3 and D4. These are marked by brown dots, The squares are the Wide Fiel).. The areas are be chosen because they are away from the Milky Way, which would clutter up the images with too many stars. The areas would be nearly overhead at the latitude of Hawaii, so no southern stars. One for each season of the year, since we see different stars at each season.

    D3 is where Hubble Deep Field is located, and also.the Groth strip

    http://www.cfht.hawaii.edu/Science/CFHLS/cfhtlsdeepwidefields.html - technical description of the 4 fields

    Do you want to look around the fields?

    Wide field W1, W2. W3. W4

    D1 happens to be in W1, and D3 in W3 (Groth strip). W3 also happens to be the North Galactic Pole, and furthest away from the main belt of stars in the Milky Way.

    http://www3.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/community/CFHTLS-SG/docs/csky.html

    Deep Fields

    The fields are 1° wide. You won't be able to find your lens candidate on these, because the co-ordinates of the SpaceWarps images are not being released for a while.

    Deep 1 http://www.cfht.hawaii.edu/images/CFHTLS-D1-Zoom/ An easier zoom in

    Deep 1 http://www3.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/community/CFHTLS-SG/docs/cfhtlsD1.html mulit-wavelength

    Deep 2 http://www3.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/community/CFHTLS-SG/docs/cfhtlsD2.html mult-wavelength

    Deep 3 http://www3.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/community/CFHTLS-SG/docs/cfhtlsD3.html multi-wavelength

    Deep 4 http://www3.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/community/CFHTLS-SG/docs/cfhtlsD4.html multi-wavelength

    For a comparison, here is the SDSS telescope footprint, it covers about 1/3 of the sky.

    enter image description here


    The CFHT has images in 3 colours - blue red and green. The light from galaxies goes through three filters, light from each filter is collected separately, and combined later. We can see more information in images of three colours, than in images of two colours like those in Hubble Zoo, or than in black and white. SDSS also has 3-coloured images, similar to CFHT

    enter image description here

    The CFHTLS ugriz filter set

    The colours used by CFHTLS and SDSS are similar.

    The colours of light coming into the telescope are not the colours that are presented to us on the screen.

    Incoming green light (g) is represented by blue on the computer screen.

    Incoming red light (r) is represented by green.

    Incoming infrared light (i) is represented by red.

    The galaxies in SpaceWarps are distant, half-way across the Universe, and their light has been red-shifted, The re-assignment of colours nullifies the redshift and makes the images look more natural, as if they were close to us.

    Lensed galaxies that we find in blue arcs have lots of ultraviolet (u) and green (g) light. They are energetic young galaxies that produce high-energy, short-wavelength light which is not affected by redshift as much as the elliptical galaxies.


    enter image description here

    http://talk.spacewarps.org/#/subjects/ASW0000p9m

    How big are these objects? Each image is 74" wide, that is 74 arcminutes.

    On this image, the bright arc is 5" away from the center of the galaxy, and the dim arc is 8" away. Some arcs will be closer. I do remember some lensed quasars at 20" away but that is unusual.

    The Moon is 2,000" wide.

    see: How much of the sky does each image represent? by c_cld.
    http://talk.spacewarps.org/#/boards/BSW0000002/discussions/DSW000052q

    The COLLECT button hides some of the image!

    You can usually right-click on that image to view it in a new tab without the "collect" obstructing the view.


    Highly technical stuff, with no pictures

    CFHTLenS: Imaging Data and Catalogue Products Erben et al, 2012 -technical information on how the data was prepared for the initial weak lensing analysis. . Only graphs and tables on testing the equipment.

    CFHTLenS Heymans et al 2012. The pipeline, that is, how the data was collected and cleaned up for other people to analyse. Only graphs and tables.

    http://www.cfht.hawaii.edu/Science/CFHTLS/T0007/

    http://www.cfht.hawaii.edu/Science/CFHTLS/T0007/T0007-docse5.html#x47-400005 The Deep Survey

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  • Budgieye by Budgieye moderator

    9 FINDING MORE INFORMATION - NED, SDSS, and other lens surveys,

    Lens Surveys

    There are many lens surveys, and I'm not sure how much they overlap, or how often they are updated. There are optical telescope surveys, and radio telescope surveys. There is data from ground-based telescopes and from space-based telescopes.

    Also, there are scientific papers which say

    "I think these are strong gravitational lenses, they look like lenses, don't they?" These are lens candidates only,

    Or

    "These definitely are strong gravitational lenses, and we have proved it by taking a spectral chart of each arc and of the lensing galaxy. The spectral analysis demonstrates that all the arcs have identical spectra, and the arcs are twice as far away as the lensing galaxy" which is more difficult and expensive to do.

    So here are a few lens surveys.

    CFHTLenS Canada France Hawaii Telescope Lens Survey.
    THE CFHTLS–STRONG LENSING LEGACY SURVEY (SL2S): INVESTIGATING
    THE GROUP-SCALE LENSES WITH THE SARCS SAMPLE
    The survey contains 127 lens candidates. SpaceWarps hopes to improve this survey.

    CASTLES Survey Centre for astrophysics-Arizona-Space-Telescope-LEns-Survey

    Finding more information about a lens

    For now, we can't easily look up information on the lens candidates.
    enter image description here

    Let us see what we can find out about this one.
    We were given a clue "This is a known lens [candidate"

    So looking at the picture of the lenses http://iopscience.iop.org/0004-637X/749/1/38/pdf/0004-637X_749_1_38.pdf

    we are lucky that it is first to look at on page 8.

    It's name is SA2 020210 - 110912, and page 7 says that it is in area W1. It is magnitude 18, so it is reasonably bright.

    Its name is also its co-ordinates. RA 02:02:10 and DEC -11:09:12. Go to

    http://www3.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/community/CFHTLS-SG/docs/csky.html

    enter the numbers in the box and press go. The galaxy is there, though the lens has little colour.

    This lens is in W1, the Wide field, but not in D1 the Deep Field.

    The galaxy is outside the footprint of SDSS, it is too far south, so we can't use SDSS dr9 Navigate
    http://skyserver.sdss3.org/dr9/en/tools/chart/navi.asp

    A search of 020210 -110912 on Google Scholar Google Scholar doesn't bring up much yet, but I'm sure more will be published in the future.

    Posted

  • Budgieye by Budgieye moderator

    10 Room for more

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  • Budgieye by Budgieye moderator

    11 NOT LENSES

    enter image description here

    http://spacewarps.org/subjects/standard/5183f151e4bb21021902286e.png

    Can see the blobs of stars forming the galaxy arm.


    enter image description here

    http://talk.spacewarps.org/#/subjects/ASW0005is2 posted by c_cld

    A good illustration of how #barred_spiral galaxies have hot spots where the spiral arms join. Can be confused for double quasar points in more distant galaxies.


    probably a quasar, not lensed

    http://talk.spacewarps.org/#/subjects/ASW0001rcc posted by Viliam

    probably a quasar, not lensed, as determined by c_cld

    see Thick Blue Ring, it's just too perfect http://talk.spacewarps.org/#/boards/BSW0000004/discussions/DSW00007j7


    Posted

  • Budgieye by Budgieye moderator

    EDIT to classifications

    June 20 - About half of the images are being retired, since nobody clicked on them after 10 viewings.
    There are about 1,500 candidates of varying degrees of reliability. Some of the good ones are discussed in Talk.
    There have been 8,000 citizen scientists participating in SpaceWarps, and 40% of them participate in Talk.
    Citizen Scientist get marked on how we perform on the #sims. Only 92% of the sims are actually visible, and 8% are below threshold. So remember to mark the arcs and quasar points, not the center of the galaxy! (I don't think I would like to know my score. When I start missing #buriedrings, I know it is time to stop.)

    EDIT to Lens Modeling

    The lens tutorial http://mite.physik.uzh.ch/tutorial/videos/all/tuto_player.html

    Spaghetti lens modeler http://mite.physik.uzh.ch/lmt.html

    post results on Modeled Candidates http://talk.spacewarps.org/#/boards/BSW0000006/discussions/DSW00004zu

    Posted

  • Budgieye by Budgieye moderator

    EDIT: Anupreeta is updating the ASW...images to make sure that "Known Lens Candidate" appears if the lens is already known.

    Posted

  • Budgieye by Budgieye moderator

    Digging Deeper with the Dashboard , a blog by drphilmarshall

    http://blog.spacewarps.org/2013/10/01/digging-deeper-with-the-dashboard/

    Meanwhile, the lensed features are usually blue – so brightest in the
    g-band

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  • Budgieye by Budgieye moderator

    Examples of using Dashboard / Open in Tools http://talk.spacewarps.org/#/boards/BSW0000004/discussions/DSW0000ckp
    Summary
    Click on Open in tools in the top right corner, then click on u to see the object in violet light.
    Slide the dark and contrast buttons until you see an image.
    Click copy, then save the address in the top left corner if you want to post the link.
    (if someone knows how to post the image, please tell me!)

    blue arc lenses from star-forming galaxies have lots of violet light, you will see bright arcs in violet light.
    red arc lenses are from inactive galaxies, nothing to see in violet light.
    double and quad points from blue quasars (z=1) they have violet light, so look in u band
    double and quad points from green, orange, yellow or red quasars (z of 4) don't have violet light, nothing in u band

    Posted

  • Budgieye by Budgieye moderator

    Can a massive black hole cause lensing?

    http://talk.spacewarps.org/#/boards/BSW0000004/discussions/DSW00000cp

    quad with lensing galaxy invisible due to redshifting

    Posted

  • Budgieye by Budgieye moderator

    Nov 22, 2013 by Dr Phil Marsha.. Coming soon: narrowing down the candidate list with Space Warps Refine http://blog.spacewarps.org/2013/11/22/coming-soon-narrowing-down-the-candidate-list-with-space-warps-refine/ sorting out the best 3,300 lenses

    Posted

  • Budgieye by Budgieye moderator

    Jan 7 2012 New Year, New Data: Hunting for lenses in the infrared with VICS82

    http://blog.spacewarps.org/2014/01/07/new-year-new-data-hunting-for-lenses-in-the-infrared-with-vics82/

    Posted

  • ams_56 by ams_56

    so much to take in and not as easy as it looks but it is so inspiring that you don't want to give up.

    Posted

  • geoffreyw by geoffreyw

    Why am I unable to zoom in on an object hen encouraged to do so? When I click in the button the image goes black and grey bands track diagonally across my screen behind the image box across the top half of my screen. Anyone else have this problem?

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  • ElisabethB by ElisabethB moderator

    What browser are you using ? IE and Space Warps are not compatible, so switching to Chrome or Firefox would be a good thing.

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  • Budgieye by Budgieye moderator

    I will put this information at the top of the page.

    Posted