Galaxy Zoo Talk

something odd

  • Amey_Daithankar by Amey_Daithankar

    i am new here.i m not able to understand what is there at background i think it is taking birth ?i m not sure

    Posted

  • ElisabethB by ElisabethB moderator

    Hi Amey Daithankar and welcome to the Zoo

    The blue fuzz is a galaxy, but it is zoomed in too much. Here 's the zoomed out and rotated image

    enter image description here

    The green dot is also a galaxy, overlapping the larger blue one.

    Don't worry, most of the objects in these images will be much more recognisable ! 😄

    Happy hunting !

    Posted

  • JeanTate by JeanTate

    Actually, as c_cld shows (see comments), the green dot is a supernova! 😮

    And apparently an unreported one!! 😮 😮 😄

    Posted

  • ElisabethB by ElisabethB moderator

    WOW !

    Posted

  • Capella05 by Capella05 moderator

    Nice one Claude!

    Posted

  • vrooje by vrooje admin, scientist

    That's really cool -- just as a check, do you know how far apart the DR7 and DR10 images were taken? It should be in SkyServer somewhere (maybe in the "field" page, if memory serves)...

    Posted

  • zookeeper by zookeeper admin, scientist

    I don't think it's a supernova; I'm not 100% sure, but the mjd (the date on which the observations are taken) is the same for both images. So are things like the run, the plate and the fibreid, which suggest that it's all the same night. The rerun number is different which usually marks a reprocessing; I know they changed the way the algorithms that put these images together between data releases.

    Right now, either (i) I'm misunderstanding how things like fibreid get updated (certainly possible) or (ii) It's a source thats bright in one colour (or more?) that's been improved by the processing. I shall have a think.

    Posted

  • c_cld by c_cld

    No the mjd are not the same as I put the original raw frames.

    It happens that we don't know how the thumbnails DR7/ DR10 are processed. We had the same pb with asteroids appearing or dashed over the runs. To be sure you have to look at
    http://dr10.sdss3.org/coverageCheck/search where for ra 204.62057 dec 2.52871 you find

    Imaging Coverage
    Run / Camcol / Field
    1462 / 4 / 528;
    6166 / 3 / 90;
    6166 / 3 / 89;
    1462 / 4 / 529;
    6174 / 3 / 83;
    1458 / 4 / 533;
    1462 / 4 / 530;

    Have a look on my links (tinyurl ) for run, camcol, field 😃

    Posted

  • zookeeper by zookeeper admin, scientist

    Thanks - was about to post that I was wrong. End of an observing run!

    And fibreid and so on are to do with the spectrum, not the imaging.

    Posted

  • c_cld by c_cld

    The spectrum has been taken on mjd 52022 (2001-04-23 ) 332 days after imaging too late for such SN !
    but it gives the redshift of the parent host galaxy...

    Posted

  • c_cld by c_cld in response to vrooje's comment.

    query on "field table":
    Your SQL command was:
    select mjd_r , dbo.fmjdtogmt(mjd_r) obs from field where
    run = 6166
    and camcol= 3
    and field = 90

    mjd_r obs
    53880.17674601 2006-5-25:4:14:30.855331

    Posted

  • vrooje by vrooje admin, scientist

    Agreed it's definitely a real source, and the image where it's not present was taken in May 2006, whereas the image with the green source was taken in May 2000.

    Cool - great find!

    Next question: how sure are we that this hasn't been reported? NED isn't necessarily complete for SNe that went off in 2000... but I don't really know who keeps the best lists of these things.

    Posted

  • c_cld by c_cld

    in Vizier

    B/sn/sncat Asiago Supernova Catalogue (Barbon et al., 1999-)

    List of SNe in chronological order on 2014-06-01 (6376 rows)

    Posted

  • zookeeper by zookeeper admin, scientist

    There are some papers of SNe in Sloan that wouldn't have been picked up by that catalogue - if I get a sec I'll try and dig them out for you.

    Posted

  • klmasters by klmasters scientist, admin

    My resident SN expert (and former office mate) claims that NED is quite complete for known supernova. So if it's not in NED as a SN it's probably not known about.

    Posted

  • JeanTate by JeanTate

    The IAU Central Bureau for Astronomical Telegrams has a website, List of Supernovae. I guess this is the same as C_cld's Vizier source. Being IAU, it's the ultimate in authority, right?

    It lists no supernova at this location.

    Posted

  • klmasters by klmasters scientist, admin

    Being IAU, it's the ultimate in authority, right?

    Astronomically yes.

    Posted

  • Amey_Daithankar by Amey_Daithankar in response to ElisabethB's comment.

    Thank you for ur reply . can u keep some tutorial or video lecture or some notes which will help me to understand many things .i m not able to understand anything. There is no one to guide me.i m blank here

    Posted

  • Budgieye by Budgieye moderator

    The bright round object may be a supernova, or it may be an overlapping star in our galaxy.

    If it is a star in our galaxy, it will be in every picture taken of that galaxy over the last 100 years.

    If it is a supernova, it will only be in images taken over a few months period when the supernova was bright. So some of the discussion was trying to decide when the image was taken. SDSS has taken images in 10 ? periods of time between 2000 and the present. That is what all the numbers are about, trying to decide when the image was taken.

    Agreed it's definitely a real source, and the image where it's not
    present was taken in May 2006, whereas the image with the green source
    was taken in May 2000.

    If it is a supernova, then databases have to be consulted to see if anyone has already noticed this supernova. Supernova are named for the year of their discovery, so it is important to find the year that the supernova was noticed. If no-one has noticed it, then it is a discovery by Galaxy Zoo.

    There are images of some supernova discovered by the SDSS telescope http://classic.sdss.org/supernova/aboutsupernova.html

    Hope that helps! 😃

    Posted

  • Budgieye by Budgieye moderator

    enter image description here

    http://skyserver.sdss3.org/dr8/en/tools/explore/obj.asp?id=1237651754021093484 image in SDSS dr 8

    enter image description here

    http://cas.sdss.org/dr7/en/tools/explore/obj.asp?id=587726032796188818 image in SDSS dr7

    Posted

  • vrooje by vrooje admin, scientist

    I agree it's clear that it's a transient source, but we'd probably want to do a bit more work to see if it's actually a supernova. There are other types of sources that can temporarily be bright, many of which happen in compact binary sources where one star is accreting matter pulled off the other. Those do include some kind of supernovae, but also things like dwarf novae and flares in X-ray binaries. I didn't see any obvious mention of this being one of those, but I haven't looked that carefully.

    This seems pretty bright to be any of the smaller transients, but it might be worth checking to see if the colors and brightness of this source really excludes them.

    No matter what it is, it's cool! But how we interpret it obviously depends on what it is.

    Posted

  • c_cld by c_cld

    Obviously, the SDSS imagery pipeline has selected this object

    ra 204.620572697569 dec 2.52870516754566 in phototag table

    for a spectrum target

    ra 204.6206 dec 2.5287017 in specobj table, SpecObjID= 594624443439933440

    Alas the delay for this spectrum observation was too long!

    You could check the ugriz data: 21.24 19.65 18.75 18.72 18.44 compatible with a SN light.

    similar more lucky SDSS example 1237652901303943234
    in GZ forum http://www.galaxyzooforum.org/index.php?topic=276420.msg651329#msg651329

    Posted

  • Budgieye by Budgieye moderator

    Any more news on this possible unreported supernova? " We talked about it about 4 months ago.

    Posted

  • Budgieye by Budgieye moderator

    Any more news on this possible supernova?

    Posted

  • Ghost_Sheep_SWR by Ghost_Sheep_SWR

    Supernova candidate AT 2000gh reported by c_cld

    https://wis-tns.weizmann.ac.il/object/2000gh

    Posted