Bamboozled
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by bluemagi
I have been trying to figure this one out. I have hit a wall.I found it on the SDSS. Its not one of ours.
1237665357237518394 Z:1.350 QSO Broadline
1237665357237518393 Z:0.033 Galaxy Broadline
1237665357237518721 Z:1.560 QSO Broadline , Not involved but on photo.
It looks as if the Quasar is overlapping a galaxy? I don't think the spectrum of the Quasar is right. It doesn't have any peaks. Reminds me more of a blue star or white dwarf. Thanks, bluemagiPosted
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by Budgieye moderator
One yellow and one blue.Strange that the interacting pair are such different colours,
I agree, that spectrum doesn't look like a quasar, and the redshift is far too high.
http://skyserver.sdss.org/dr14/en/tools/explore/summary.aspx?id=1237665357237518394
http://skyserver.sdss.org/dr14/en/tools/explore/Summary.aspx?id=1237665357237518393
Posted
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by JeanTate in response to bluemagi's comment.
1237665357237518394 Z:1.350 QSO Broadline
It's not a QSO, rather most likely a local (in our own Milky Way galaxy) star, spectral class A (the absorption lines, decreasingly deep with wavelength; the continuum like a blackbody). Other interpretations? Let's hear them! 😃
1237665357237518393 Z:0.033 Galaxy Broadline
OK, except for the BROADLINE part (all emission lines seem pretty narrow to me).
1237665357237518721 Z:1.560 QSO Broadline
Yep.
Hope this helps, and happy hunting! 😃
Posted
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by bluemagi
Thank you, Budgieye and Jean Tate
Posted
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by JeanTate in response to JeanTate's comment.
It's not a QSO, rather most likely a local (in our own Milky Way galaxy) star, spectral class A (the absorption lines, decreasingly deep with wavelength; the continuum like a blackbody). Other interpretations? Let's hear them! 😃
Correction: it is indeed a very A-like spectrum, but it's certainly not from a star in our own galaxy! Why? Because it has a redshift of ~0.03! 😮
So, what is it?
A fading intense, and very localized, starburst. The O and B giants created in the starburst have all gone supernova, leaving the main-sequence A stars dominating the visible light. I do not know why there is no "K" (for K giant and supergiant stars) component in the spectrum; "K+A" is a typical "quenched" spectrum, what's left when a starburst has faded. Perhaps this fading starburst has been caught at a very particular time, before any "K" component becomes visible (typical K+A/quenched objects look white in SDSS images, because there's a red continuum to balance the blue "A" part).
All in all a very interesting set of objects! 😃
Posted
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by mlpeck
The interacting pair is I Zw 136. There are HST and Spitzer images on page 1 of this discussion: https://talk.galaxyzoo.org/#/boards/BGZ0000007/discussions/DGZ0001z7q.
Yes, the spectrum indicates a powerful starburst that was very recently shut down although the HST and Spitzer images suggest there is still considerable star formation that's well hidden.
Posted
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by bluemagi
Thanks, mlpeck. Very interesting.
Posted
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by mlpeck
repost of hst image:
(my attempt at an rgb composite of 3 filter acs imagery)
Posted
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by Ghost_Sheep_SWR in response to mlpeck's comment.
here is the Hubble image from the ESA site. I wonder what the speckled little thing in the center is (near the bottom in your image).
Image credit: ESA/Hubble & NASA Acknowledgement: Judy Schmidt
https://www.spacetelescope.org/images/potw1432a/
Posted
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by mlpeck in response to Ghost_Sheep_SWR's comment.
I wonder what the speckled little thing in the center is
A small, probably starforming, irregular galaxy I'd guess. Zoom in! Similar objects are all over the field, including a larger and brighter one near the red disk galaxy.
Posted