Examples of using Dashboard / Open in Tools
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by Budgieye moderator
Why click on Tools / Dashboard.? To look for ultraviolet light
blue arcs have UV light
blue galaxies "near" to us don't have much UV light
so we can tell if an blue arc is a lensed galaxy, or just something nearby.
There are 5 bands of light at various wavelengths that are recorded by the ccd camera.
u violet (nearly ultraviolet)
b blue
g green
r red
i far red (nearly Infrared)Only 3 of these bands are used to make images. Our computer screens can only deal with 3 colour channels, so it uses only g, r and i bands.
green (g) light from the star, and turns it into blue
red (r) light from the star, and turns it into green
far red (i) light from the star, and turns it into red
u (violet light ) and b(blue light) aren't used for the images.
Using Tools / Dashboard, we can look for violet light. Energetic light from distant lensed galaxies has a lot of ultraviolet (UV) light and hopefully we can detect that by looking for violet light, which is also high energy.
For information on spectral charts, see
Zooite Guide to SDSS Spectra http://www.galaxyzooforum.org/index.php?topic=274815.0
and
Colours of Galaxies in SDSS : Redshift chart http://www.galaxyzooforum.org/index.php?topic=277142.0 (SDSS telescope has fuzzier images, but the colours are the same)
Click on the u band to find how much violet light there is. Arcs have violet and ultraviolet light, which is denoted by u.
Click on copy to save the settings, and then copy the address.
Finding buried arcs
violet (u band) ring under the pink arc
http://talk.spacewarps.org/#/subjects/ASW0009ab8 posted by C_cld
http://tools.zooniverse.org/#/dashboards/spacewarp/52743a60fe16d9399c000023
Finding buried quasars
#sim slightly suspicious blue edge to nucleus in this sim
http://talk.spacewarps.org/#/subjects/ASW0002vrd posted by leonmir56
#sim buried Einstein cross visible in u band http://tools.zooniverse.org/#/dashboards/spacewarp/5276f3ca72c1091e0c000075...
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by Budgieye moderator
Dashboard / tools not useful for finding lensed quasars.
Quasars don't have a u band? Blue quasars already have their UV light ( Lyman alpha radiation) redshifted to blue, so they don't have any UV light left to make a u band.
Here is a sim
http://talk.spacewarps.org/#/subjects/ASW0000sbg posted by surhudm
Here is the u band (violet light) http://tools.zooniverse.org/#/dashboards/spacewarp/527519b1fe16d95efd000047 , quasars are not visible.
Here is the g band (blue light) http://tools.zooniverse.org/#/dashboards/spacewarp/52751a0572c109248d000049, can see the quasars, but it also could be small blue galaxies or blue stars.
Here is the r band (green light) http://tools.zooniverse.org/#/dashboards/spacewarp/52751a8d72c109248d00004c, can see the quasars, but it also could small green galaxies, or white stars.
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by Budgieye moderator
A sim but not a #dimsim, it is totally amazing in Tools / Dashboard / u band http://tools.zooniverse.org/#/dashboards/spacewarp/5274452672c1090333000046
To save the settings on dashboard /tools , click on the copy button, then copy the address bar to your post. Anyone know how to post the dashboard image?
http://talk.spacewarps.org/#/subjects/ASW0007mmh posted by HelPer2
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by Budgieye moderator
Finding detail in blobs of white light. Separate the g band (blue) from the red (i band) dust
http://talk.spacewarps.org/#/subjects/ASW000085w posted by dtrucken
#dust_lane visible in the g band in dashboard http://tools.zooniverse.org/#/dashboards/spacewarp/52743713fe16d9399c000020
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by Budgieye moderator
bright blob
http://talk.spacewarps.org/#/subjects/ASW0000a2d posted by TED91
double nucleus, seem in g band http://tools.zooniverse.org/#/dashboards/spacewarp/52743893fe16d939a900001e
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by Budgieye moderator
Illustrating that blue quasars do not have UV light.
Training image/sim quasar points easily visible in blue light
http://talk.spacewarps.org/#/subjects/ASW0008c4h posted by fermor332002
quasar points barely visible in u band, lensing galaxy not visible in u band dashboard http://tools.zooniverse.org/#/dashboards/spacewarp/52759278fe16d9039f00015a
Posted
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by Budgieye moderator
Why click on Tools / Dashboard.? To look for ultraviolet light
blue arcs have UV light
blue galaxies "near" to us don't have much UV light
so we can tell if an blue arc is a lensed galaxy, or just something nearby.
There are 5 bands of light at various wavelengths that are recorded by the ccd camera.
u violet (nearly ultraviolet)
b blue
g green
r red
i far red (nearly Infrared)Only 3 of these bands are used to make images. Our computer screens can only deal with 3 colour channels, so it uses only g, r and i bands.
green (g) light from the star, and turns it into blue
red (r) light from the star, and turns it into green
far red (i) light from the star, and turns it into red
u (violet light ) and b(blue light) aren't used for the images.
Using Tools / Dashboard, we can look for violet light. Energetic light from distant lensed galaxies has a lot of ultraviolet (UV) light and hopefully we can detect that by looking for violet light, which is also high energy.
Posted
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by Budgieye moderator
X marks the spot in violet light, u
Exploring aprajita's blog
http://talk.spacewarps.org/#/subjects/ASW0004dv8 posted by rotex
can see complete ring in u, but it is faint
http://tools.zooniverse.org/#/dashboards/spacewarp/5279ea6072c1095eb1000027
http://talk.spacewarps.org/#/subjects/ASW0003wsu posted by bernmeister
violet light http://tools.zooniverse.org/#/dashboards/spacewarp/5279e8ce72c10947e2000334
http://talk.spacewarps.org/#/subjects/ASW00047ae posted by FBloggs
violet is quite bright http://tools.zooniverse.org/#/dashboards/spacewarp/5279eac5fe16d92fd1000009
http://talk.spacewarps.org/#/subjects/ASW0005mp6 posted by ElisabethB
nothing much in u http://tools.zooniverse.org/#/dashboards/spacewarp/5279ec0572c1095eb100002b
http://talk.spacewarps.org/#/subjects/ASW0004q9e posted by tashipoo
http://tools.zooniverse.org/#/dashboards/spacewarp/5279ecd2fe16d9139600004d
http://talk.spacewarps.org/#/subjects/ASW0001yqb posted by mitch
looks almost like a quasar double, though not bright
http://tools.zooniverse.org/#/dashboards/spacewarp/5279edc972c109491d0000a1
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by HelPer2
So, just so I understand, for a possible arc it's worth using Tools and looking in u band, where a true arc should be visible? And for possible quasar, it perhaps wouldn't be?
Also, is it possible that if seeing a possible arc, but with no visible lensing object, looking in Tools might reveal there was something massive enough there? (BTW if so, I might have to go back through all my images to check them!)
ThanksPosted
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by Budgieye moderator
It is possible to have an invisible lensing galaxy, just not likely. It would be an elliptical galaxy, with no star formation, hence no UV light. The galaxy would have to be very far away, z=1.0 for all it its blue light to be redshifted into the infrared, which our telescope doesn't see.
I suppose it is always possible to have dark matter without an accompanying galaxy. I don't think one has been found yet, but we in SpaceWarps are pushing back the frontiers of science.
There was a quad quasar published z=3 I think, with an invisible galaxy, I keep intending to re-post it when I find the reference again.
I don't think that it would be necessary to go back and look up old images. The arc would still be there in the other colours, but there is more contrast in violet, since there isn't much violet in galaxies.
Most distant lensed galaxies are star-forming. Distant galaxies are younger, and so produce lots of blue, violet and ultraviolet light. But since no two galaxies are alike, I suppose there could still be smaller and dimmer ones which would make dimmer arcs.
Any closer elliptical galaxies z=0.6 that get lensed ,will be red galaxies, and they would be lensed into a red arc, with no other colours.
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