Outburst / passing object?
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could a scientist / moderator please take a look at the object / feature near the center at 2 in SDSS9? Doesnt look like an artifact, and almost seems like it moved on to 5 in DECaLS, near the yellowish pixel. Looks interesting
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by
JeanTate
in response to Ghost_Sheep_SWR's comment.
I think it may be some kind of artifact in DR9.
DR9 image:
DR7 one:
... or not ... the DR7 and DR9 (same as DR10, DR11, DR12) images seem to have been taken at different times (DR7, then DR12):
- run: 3560, 3606
- mjd_r: 52664.25678905, 52639.3078 (5.26393078E4)
That's ~25 days' different, or ~one lunation ...
More: in the DR7 "More Observations" (Under PhotoObj), a third observation is given (run 3644, mjd_r 5.26712159E4); here's the corresponding image:
Curious, no?
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Absolutely! You process information fast! 😃 very informative, no clue how you calculated 25 days, but really to short for any galactic process to be seen, so likely something with saturation artifact. I didn't know about 'more observations', cant spot any difference between the 2 DR7 observations, except PhotoZ 0.07869 and 0.138383 respectively (?) 😃
Thanks very much for the input!Posted
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by
JeanTate
in response to Ghost_Sheep_SWR's comment.
You're very welcome! 😃
no clue how you calculated 25 days
Here's the DR12 Explore page, and here's the DR7 one, for this object. On the left is a frame with many sections; one is "PhotoObj" (DR7) "Imaging Summary" (DR12). If you click on "PhotoObj" (DR12), you get a lot of info about the photometry for this object ... including a field "mjd"; for DR7 that info seems to be under "Field". "MJD" stands for Modified Julian Date, and is one way astronomers timestamp data.
I didn't know about 'more observations'
One odd thing: DR7's "More Observations" says there are two, but DR12's gives none.
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And another PhotoZ from DR12 (DR4 under galspecinfo) : 0.066459, take your pick!
| One odd thing: DR7's "More Observations" says there are two, but DR12's gives none.
Actually on the Imaging summary page DR12 states there are 4 more observations 😃
And it really seems like an object / same artifact in DECaLS but on another location, which would be +1 strange
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by
JeanTate
in response to Ghost_Sheep_SWR's comment.
And another PhotoZ from DR12 (DR4 under galspecinfo) : 0.066459, take your pick!
When quoting photoz's, I think it's important to also quote the stated ± values (a.k.a. 'uncertainties' or 'error bars'); yes, different photoz's for the same object are often quite different (different algorithm, different data/images), but do their error bars not even overlap?
And it really seems like an object / same artifact in DECaLS but on another location, which would be +1 strange
Agreed. However, it seems to me they're quite different things, not even the same sort of artifact ... how to decide between these two (different) perceptions?
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by
Ghost_Sheep_SWR
in response to JeanTate's comment.
| When quoting photoz's, I think it's important to also quote the stated ± values
I understand. In this case with both PhotoZ + or - Error values are 0.097003 and 0.10153 so no overlap but with a difference this small can be discarded i guess.
| Agreed. However, it seems to me they're quite different things, not even the same sort of artifact ... how to decide between these two (different) perceptions?
Hope and positive thinking will always give it the benefit of the doubt to me 😃 ill try other surveys some more to see of theres anything odd, which i always do first as much to my abilities before posing a question about an object / artifact.
Thnx
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by
c_cld
Your object http://skyserver.sdss.org/dr12/en/tools/explore/Summary.aspx?id=1237660961325252621
is a "muffin".
Look at http://www.galaxyzooforum.org/index.php?topic=10003.0 or artifacts not removed from neighbors stars. 😃
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Lol muffins, very enlightening! Although the shape doesn't equal the simpler round artifacts in the forum thread you posted to me; this one also has a connection bridge to the center of the galaxy... Subspecies 'drooling muffin'? 😃
Anyway id say case closed, verdict (weird) artifact, likely muffin.
Hulde!
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