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Thread: Object of the Week, April 24, 2023 – SDSSJ0849+1114

  1. #1
    Member Howard B's Avatar
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    Object of the Week, April 24, 2023 – SDSSJ0849+1114

    Cancer
    Triple galaxy merger
    RA: 08 49 05
    Dec: +11 14 51

    SDSS0849+1114.JPG
    (The image above is from a paper given by Ryan Pfeifle in 2019, titled “Uncovering Dual and Triple AGN’s in Galaxy Mergers”, which can be seen at: https://cxc.harvard.edu/symposium_20...an_pfeifle.pdf)

    I’m pretty sure this is an object that Jimi turned me on to, so you know it’s awesome.

    Located about a half degree south of the open cluster M67 is the faraway triple galaxy merger, SDSSJ0849+1114. I observed it almost exactly three years ago from my moderately light polluted backyard with my 28-inch f/4 scope. I had no thoughts of seeing the three galaxies individually, and only hoped to detect their combined glow – which I was able to do. What made this observation special is that the light travel time for these merging galaxies is 1.032 Gly – wow!

    Just as amazing is that their co-moving radial distance – or how far away they are right now – is 1.072 Gly, which means the universe has expanded by about 40 Mly during the light travel time. So, this barely visible glow gave me the intellectual thrill of experiencing the expansion of the universe. Wow again!

    The fact that I saw it from my backyard under a fairly normal sky for the location should mean that, under a dark and transparent sky, SDSSJ0489+1114 is accessible to much smaller scopes than my 28-inch. I can’t find a visual magnitude, but based on its appearance, I’ll guess it’s around 16th magnitude. Here are my observing notes and sketch:

    “Billion-year-old / instantaneous light – I don’t think I’ll ever get used to this… Great way to start the evening, especially because this tiny, barely seen smutz isn’t even in the darkest part of the sky. I first saw it at 253x, but it was more difficult at 408x and 547x. 695x did the trick and I could see it about 50% of the time with averted vision – awesome! 20.23 SQM, April 16, 2020”

    SDSSJ0849+1114 sketch_2.JPG SDSSJ0849+1114 sketch_2_invert.JPG

    The DSS2 image below shows the three galaxies merging – something I had no hope of seeing from my backyard. But who knows, maybe the tidal arms from the merger can be detected under an excellent sky – so give it a go and let us know!

    SDSSJ0849+1114 DSS2 image.JPG
    Howard
    30-inch f/2.7 alt-az Newtonian
    https://sites.google.com/site/howardbanichhomepage/
    https://sites.google.com/site/sprays...pemirrors/home
    Contributing Editor, Sky & Telescope magazine

  2. #2
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    A really interesting target! It's in Sky Safari as PGC 1390839 (I'm assuming that's also a LEDA designation.) It also gives a magnitude of 16.79.

    Here's the SIMBAD data: https://simbad.cds.unistra.fr/simbad...=SIMBAD+search

    And NED: http://ned.ipac.caltech.edu/byname?o...map=4&corr_z=1

    I'm going to have to try this one in the 20" to see if anything of it is detectable--that is, if the skies ever clear....
    Last edited by KidOrion; April 26th, 2023 at 03:16 PM.

  3. #3
    Member Steve Gottlieb's Avatar
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    HyperLEDA data also lists B = 16.66 ± 0.5.

    For comparison, SDSS photometry (DR12) suggests V = 16.3 and B = 16.8, pretty similar to the other values.
    Steve
    24" f/3.7 Starstructure
    14.5" f/4.3 Starmaster
    Adventures in Deep Space
    Contributing Editor, Sky & Telescope

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