Interesting object

https://www.legacysurvey.org//viewer/?ra=338.2384&dec=-58.1307&layer=ls-dr10&zoom=16&ngc&const

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If you click on ‘look up in SIMBAD’ you can find more info / references on objects.

If in the object page in SIMBAD you click on ‘ Search by coordinates in Vizier (radius: 5 arcsec)’ you can find all catalog references on an object.

Hope this helps, happy hunting!

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What form of coordinates do I put into Vizier and how on earth do I read the object type from the resulting query? I am probably stupid and I can’t seem to make sense of this.

You don’t

Clicking the Legacy Survey viewer link to SIMBAD and then on the SIMBAD object clink on the link to the VizieR query takes no input. With the exception if there is no SIMBAD object page(always check the distance in arcsec from your chosen coordinates!)

In SIMBAD you can expand the list of references (papers) to your object and find info there

VizieR is (AFAIK) nothing more than a collection of catalogs, a lot of the time automated like GAIA and the likes

But it is easy to skip most of the general catalogs like that and look for catalogs of the specific object type you might have found (like SuGoHi for lenses). All catalogs have a ‘Readme’ link which explains what’s in them, and some of them have an object type code in the object line, for instance IIRC SuGoHi has a code for lenses, something on the lines of (from the top of my head!) 1 - gravitational lens 2 - probable gravitational lens 3 - possible gravitational lens

So checking (references in) SIMBAD and catalogs in VizieR gives information about whether an object is already ‘known’, as confirmed or candidate, etc.

It’s the latter (no page). Think 2 arcmins is standard and if I couldn’t find anything there its confusing. Thank you for the clarification though - very helpful.

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For example take the object from OP above;

Go to the viewer, click on ‘Look up in SIMBAD’ and you presented with two objects, a g-lens image candidate and a g-lens candidate.

Both have 1 reference, I usually go for object with most references

In the first objects’ page I click on ‘Display’ below References 1 and see which paper designated it as ‘Gravitationally Lensed Image Candidate’

Then click through to ‘Search in VizieR 5 arcsecs’, ignore all the usual catalogs at the top and find two catalogs on Lenses at the bottom

Hope this helps :slight_smile:

Yeah 2 arcmins is usually way too large a search area in my opinion, 5-10 arcsecs should do the trick usually, my SIMBAD (settings?) starts with 5 arcsecs for VizieR query

For searching directly in VizieR using coordinates you have to choose between two search boxes,I’ve learned to use the second (lower) one

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Yes lower one seems to work better.

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I usually do that for most but I expand if I don’t get anything. I think the post where we were talking about changes in AI and machine learning has no results within 2 arcmins of the centre of the image

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