Galaxy Zoo Talk

SDSS to GAMA

  • karthikeyan.d by karthikeyan.d

    Is there a way to find if an SDSS object has been imaged in GAMA and get that image? The Single Object Viewer in the GAMA site asks for things like CATAID and SPECID. I wanted to see how the following looked in GAMA.

    AGZ000D5FV

    enter image description here

    Posted

  • Budgieye by Budgieye moderator

    Nope, I haven't figured it out yet either. Your object link doesn't work for me.

    Maybe KiDS DR3 data access http://archive.eso.org/wdb/wdb/adp/phase3_main/form?phase3_collection=KIDS

    Posted

  • Ghost_Sheep_SWR by Ghost_Sheep_SWR

    Use lower-case letters AGZ000d5fv

    Posted

  • Budgieye by Budgieye moderator

    I thought I had tried lower-case, but I must have done it incorrectly.

    I put the co-ordinates of AGZ000d5fv, into KIDS but didn't get a answer. It must be off the viewing area.

    I also tried with https://talk.galaxyzoo.org/#/subjects/AGZ000djcy and got a result, but haven't figured out how to work it yet.

    Posted

  • Ghost_Sheep_SWR by Ghost_Sheep_SWR

    Nah me neither. I've changed the Search Box to 70 and Sort Result By RA Dec, and get objects very far away.

    In this result page you can also select View Sky to get an overview of the region in an Aladin light viewer.

    But anyway it looks that the returned files are all FITS files, and you need an ESO portal account to retrieve them it seems.

    Posted

  • bamford by bamford scientist

    You can search the GAMA data release around a position using this form:
    http://vizier.u-strasbg.fr/viz-bin/VizieR-3?-source=J/MNRAS/452/2087/inputcat

    I suggest a search radius of a few arcsec. That will give you a CATAID that you can put into the Single Object Viewer.

    However, note that the GAMA data only covers a small area of sky: 150 sq. deg. compared to ~10000 for SDSS and ~1000 for KiDS (when it is finished). The GAMA-KiDS images in GZ are currently only for the G09 region. You can see the GAMA coverage here: http://www.gama-survey.org/dr2/

    If you're feeling very adventurous, you can also query the GAMA database using SQL: http://www.gama-survey.org/dr2/query/

    Posted

  • Budgieye by Budgieye moderator

    I get this image for example. How do I get to a pretty full colour image? if I were working back from only ra, dec

    enter image description here

    http://casjobs.sdss.org/ImgCutoutDR7/getjpeg.aspx?ra=139.341462647231&dec=0.321911141449143&scale=0.2&opt=IGPO&width=512&height=512

    https://talk.galaxyzoo.org/#/subjects/AGZ000dixa

    http://www.gama-survey.org/dr2/tools/sov.php?cataid=601323

    Posted

  • bamford by bamford scientist in response to Budgieye's comment.

    Good point!

    Have a go at this tool... http://cutout.icrar.org/psi.php

    Although the KiDS data isn't in it there yet! (It's hot off the press and straight into GZ!). It will hopefully be added soon. In the meantime, you can explore a vast array of wavelengths. Also note that the VIKING data is generally higher resolution than SDSS (although in the near-infrared).

    Posted

  • Ghost_Sheep_SWR by Ghost_Sheep_SWR

    Well does look like a handy method of getting SDSS single band FITS cutouts too ๐Ÿ˜ƒ

    Thanks for the link

    Posted

  • karthikeyan.d by karthikeyan.d in response to Ghost_Sheep_SWR's comment.

    I too did not get any results for this object's co-ordinates. I then checked with a GAMA object itself

    https://www.galaxyzoo.org/#/examine/AGZ000djbl

    I used its RA and DEC in the KiDS page. A list of objects were presented but none matched the given co-ordinates. Do I have to set/change some other search criteria?

    Posted

  • karthikeyan.d by karthikeyan.d in response to bamford's comment.

    I tried VizieR for AGZ000d5fv and got nothing. Looks like this object may not have been part of the GAMA-KiDS survey.

    BTW, the RA and DEC values taken from the GZ Examine page, the SDSS SkyServer page and even from the GAMA Single Object Viewer page do not seem to work on VizieR. I then tried the CATAID of a GAMA object and found that theVizieR data seems to require the RA and DEC values in exactly 5 digits of precision. I checked this using the GAMA image AGZ000djbl. I then adjusted the RA and DEC of AGZ000d5fv and still got no results.

    Posted

  • Ghost_Sheep_SWR by Ghost_Sheep_SWR in response to karthikeyan.d's comment.

    I'd say the scientists are better suited to answer your questions, but as mentioned the new surveys cover a relatively small portion of the sky, and not all data is in their database yet.

    As for the digits, when you remove digits you also change the position where you search for an object. Below the RA Dec boxes there is also a Search Box with a given value ( sort of a search radius around your RA Dec location), so changing the center of that search radius migh move the object out of that circle and you get no results ( IMHO ๐Ÿ˜ƒ )

    Posted

  • bamford by bamford scientist

    AGZ000d5fv has dec = 35.84564, so definitely isn't in GAMA field, which is equatorial (dec~0).

    AGZ000djbl does work (129.42947 -0.16017), but Ghost_Sheep_SWR is correct, removing digits will move the position too far compared with distance between objects.

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  • bamford by bamford scientist

    GAMA coverage is given in table here: http://www.gama-survey.org

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  • leeskelvin by leeskelvin scientist

    Just catching up with the discussion here! Yes, as has been said, only the G09 GAMA field is currently in Galaxy Zoo (~11,500 galaxies across ~60 sq. deg.).

    Eventually we will be adding G12 and G15 for a total of ~50,000 galaxies covering ~180 sq. deg.

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  • ElisabethB by ElisabethB moderator

    Thanks Lee ! So, there will not be a shortage of galaxies to classify ! Great news ! ๐Ÿ˜„

    Posted

  • Ghost_Sheep_SWR by Ghost_Sheep_SWR

    Should be a good two weeks worth of classifying ๐Ÿ˜‰

    Are the GAMA redshifts / spectra publicly available for us? I can't seem to find any in the object pages.

    Posted

  • leeskelvin by leeskelvin scientist

    Hi Ghost_Sheep_SWR,

    Yes, many of the GAMA redshifts and spectra are publicly available. Right now, just over half (~56%) of the GAMA redshifts have been made publicly available as part of our data release 2 (DR2) catalogues. Many of the remaining redshifts will be made available later this year in DR3.

    For the galaxies which do have a redshift in DR2, you can easily access them through the GAMA single object viewer which is linked to on the 'Galaxy Zoo examine' page.

    Once you're on the GAMA single object viewer page, click on the link named 'spectra' at the top which will skip you down the page to an image of the spectrum for this galaxy. At the top of this image is a summary of all the spectral information we have for that galaxy, including its redshift (z) and the quality of that redshift (nQ). Quality ranges from 1 (poor) to 4 (excellent).

    For example, for this galaxy: http://www.gama-survey.org/dr2/tools/sov.php?cataid=601370 , the redshift is z=0.09152 and the quality of the redshift is nQ=4 (excellent).

    For those galaxies which do not have a redshift available in DR2, you can estimate the distance to the galaxy right within the Galaxy Zoo examine page. For each galaxy we provide the apparent magnitude and the absolute magnitude (derived from our internal redshift catalogues). These two parameters allow you to calculate the distance modulus (https://en.wikipedia.org/wiki/Distance_modulus) which, with a little bit of maths, allows you to calculate the distance to the galaxy in parsecs.

    I hope that answers your question - please let me know!

    Best,
    Lee Kelvin

    Posted

  • Ghost_Sheep_SWR by Ghost_Sheep_SWR

    Hi Lee Kelvin,

    Yes it certainly does, I probably just have hit a few galaxies for which the redshift isn't added to the database yet.

    Thank you for the feedback!

    Alexander

    Posted