(Possible) Confirmed Voorwerp EELR
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EDIT: for future reference please use my real name Alexander Jonkeren (in accordance with Zooniverse guidelines)) instead of my fantasy account name, thanks in advance
This might be an unreported Voorwerp or (EDIT) EELR.
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it is not in the GZ paper on giant AGN-ionized clouds
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according to NED that is a (disturbed) Seyfert 2 galaxy next to it (orange at 10:30)
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looks very purple and formless
RA,dec
28.64465388, 64.63154308
01:54:34.71, +64:37:53.55
Object ID 1237671068466742702http://skyserver.sdss.org/dr9/en/tools/explore/obj.asp?id=1237671068466742702
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I can rule out a flare from the star below it- it shows up in pan-STARRS too. The galaxy's dimensions are a bit hard to estimate, but the candidate voorwerp is 11,000-13,000 light years across, and the galaxy is very roughly 40,000 to 70,000 light years across.
I'm not a voorwerp expert but it seems like a good candidate.
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Complete SIMBAD overview for GZ paper on EELR's. No specific object types unfortunately, so a definitive 100% SIMBAD search is not possible.
So I really think this is probably a Voorwerp, and it isn't known as EELR yet.
I am curious what others think about this or what else it can be.Posted
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CeciliaB
Bill Keel wrote in the Galaxy Zoo blog just before Christmas: Work on Voorwerpjes continues in many ways. Galaxy Zoo participants still find possible clouds and the moderats have been excellent about making sure we see them.
My experience of AGN-ionized clouds may be limited, but I think this object looks promising enough to be investigated further.
One might start by eliminating other blueish patches. This purple object doesn't have the white blue colour of starformation. Neither does it look like an HII-region, which is a darker blue, I think. So what other purple objects are there?
The host Seyfert 2 galaxy is included in a gamma-ray source catalog, according to NED, but it's difficult to know if that information is of any importance in solving this puzzle...
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Both thanks for your analysis, and I will try to find that blog.
For your question; In general i'd say there needs to be some disturbance in combination with an AGN past or present, which I think both are present here.
In particular; looking at Table 5 of the GZ paper, a Sy 2 nucleus does appear to be a common denominator among the confirmed EELR's. I would not know what implications the gamma-ray reference would have for this candidate.
Thanks!
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ElisabethB
moderator
in response to Ghost_Sheep_SWR's comment.
Here's the blog post in question : https://blog.galaxyzoo.org/2016/12/20/new-hubblegemini-results-history-of-fading-agn/ š
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ļ good to see they are still working on the known voorwerpjes and keeping an eye out for candidates. Indeed a bit surprising the clouds aren't 'blown away' by the AGN but are simply orbiting the galaxy. Maybe MaNGA can help out š
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Budgieye
moderator
I will ask Bill Keel to look in on this.
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Great, fingers crossed.
Below near-infrared study from 1997 already commented on the region with "HII region?", but at least it is with a question mark.
http://ned.ipac.caltech.edu/cgi-bin/ex_refcode?refcode=1997PASJ...49...47I
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Dolorous_Edd
SDSS/ NVSS overlay
it is also a radio source
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That looks great Dolorous_Edd, I am aware of the amount of work that is needed to create such an overlay, thanks!
I really wasn't aware of the relation between Voorwerpjes and radio emission, but going through the original paper there does seem to be a correlation. So an additional positive EELR indication.
Two excerpts from The galaxy zoo survey for giant AGN-ionized clouds: past and present black hole accretion events. W.C. Keel et al;
Page 2:
Narrowband images revealed extended emission-line re- gions (EELRs)
around some luminous AGN, particularly radio-loud QSOs as well as
radio galaxies, as reviewed by Stockton, Fu, & Canalizo (2006).Page 13:
Eight of the galaxies qualify as radio-loud if one uses a simple, representative division at 10^23 W Hzā1, and only one lies >above 10^24.
(And found a small misstake on page 8 ;D )
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Budgieye
moderator
I would like it if Dolorous Edd can explain why the overlay is on the side opposite the blue cloud? I'm sure his guess is better than 10 hours of research from me.
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JeanTate
in response to Budgieye's comment.
The radio survey which Dolorous_Edd is using is NVSS, which has a resolution of ~45" (from memory). The tool he used to create the contour overlay is Aladin (I think).
the overlay is on the side opposite the blue cloud
It's a visual artifact; at the NVSS resolution, there's no way to tell which 'side' the radio emission seems to be on. In fact, I doubt you can say anything much, other than that the (distorted) elliptical seems to be the source of the radio emission (the 'host'), which is indistinguishable from a point source. This is consistent with the source being the immediate environs of the SMBH at the center of the nucleus (it may also be consistent with it being a recently formed nuclear star cluster, but I suspect it's too energetic).
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Budgieye
moderator
Thank you JeanTate, that's great!
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NGC3314
scientist
We may have a winner! The SDSS images looked promising, so we put this on the list of objects needing spectroscopic followup. A few nights ago, after a local schedule switch, Alexei Moiseev was able to get a long-slit spectrum of this galaxy with the 6-meter telescope of the Russian Academy of Sciences. The slit ran along the axis of the blue SDSS cloud, just about through the star to the southwest. First - the SDSS cloud is almost certainly AGN-ionized, with very strong [O III] and He II emission stronger than we see from stars in H II regions. Second - that cloud is only the tip of the iceberg. On the opposite side, there is similar emission too faint to see in the SDSS composite images, extending almost twice as far from the AGN. Here is a view of part of the spectrum - wavelength increases left to right, and the foreground star's spectrum goes across the lower part of the image. He II is the weak spectral feature near the left edge, with H-beta and the two [O III] lines much stronger toward the right. This system does look like it satisfies the criteria for our Voorwerpje sample (we see emission out to 17 kpc, lit up by an AGN); too early to say whether it shows evidence of fading, but it needs to go into our analysis sample either way. With luck in the weather, Alexei will be able to try 2-dimensional mapping of the velocity structure before the object goes behind the Sun for several months.
Well spotted, and keep it up!
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That is really exciting news,
Lets hope Alexei manages to do so (talk about foreground stars..), nonetheless I greatly appreciate the feedback!
Thanks very much NGC3314 and ofcourse Budgieye and ElisabethB.
Alexander Jonkeren
PS. I am not familiar with the old forum but maybe someone should check if this one was commented on before?
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NGC3314
scientist
We never caught it in the original Voorwerpje search, and I looked through all image threads on the old GZ forum - I'm pretty sure this part of the sky was covered only in the SDSS data releases after that.
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Budgieye
moderator
Congratulations on a great find, Ghost_Sheep_SWR !
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Thank you very much, i'm so excited!! š š but also a bit cautious until everything is 100% confirmed.
If definitely confirmed as AGN ionized cloud this would be what, #20 in a 10 year search? That's as rare as they come š (EDIT #23 is more likely).
Thanks
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moisav
I just reduced the data obtained at the 6-m telescope with the scanning Fabry-Perot interferometer two nights ago. Indeed, the ionized gas cloud in [OIII] has a complex structure more than 25 kpc in a size. You are welcome to compare the old SDSS image of this field and new one with ionized oxygen emission overlapped:
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moisav
And also the ionized gas velocity distribution. On my first look it seems more complex comparing with the previous Voorwerpje objects
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That is so beautiful and seriously messed up, thank you! Don't think I've seen such a thing before from previous Voorwerpjes. Sort of orbiting but asymmetric and with a detached part... WOW.
I now understand what was meant with 'extending on the other side' and 'tip of the iceberg'.
So I guess it is safe to conclude new Voorwerp with 100% certainty now?
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Hmm if only such a small part of it is visible in SDSS makes me wonder how many existing Voorwerpjes we are actually missing because they don't get above this visability threshold...
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NGC3314
scientist
We know we're missing some (many?), if nothing else because more detailed observations often show the known clouds to be more extensive than the (short) SDSS exposures. I've been doing a survey with a narrow [O III] filter trying to find faint ones; it's very slow going, but we've turned up a new cloud 13 kpc from a Seyfert galaxy and a few more candidates not yet observed spectroscopically.
(The post above is the first time I saw Alexei's new Fabry-Perot data- spectacular, and showing yet another part force cloud that we didn't know about from his first long-slit spectrum).
I won't get into the Voorwerp/Voorwerpje distinction, since it's not a formal thing and so much in the way of new data is still coming in.
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Ah ok thanks for the feedback. I was trying to figure out why this is the case; it looks to me that we see the clouds best at 495 - 500 nm and SDSS gri bands are too much above and below this wavelength and not exactly at ~ 495-500 nm?
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NGC3314
scientist
These clouds have their peak energy output (in the optical bands) in the two [O III] emission lines at lab wavelengths 495.9 and 500.7 nm (times 1+z for redshift z). The SDSS bands are pretty broad (100 nm or so), so they include a lot of starlight diluting the color signature of emission ones inside the galaxy, and including all the skyglow in that band. Also, to cover so much of the sky, the SDSS images expose at each position for about 54 seconds per filter. Even with the smaller 1-meter telescope I use for the imaging survey, a 60-minute exposure with a narrow filter tuned to slightly redshifted [O III] will show fainter clouds.
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Budgieye
moderator
Congratulations Ghost_Sheep_SWR on the DAILY ZOONIVERSE discussion on your object.
https://daily.zooniverse.org/2017/03/06/its-dutch-for-object/
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Thank you! Next to hunting for rare things I also do enjoy some good media exposure for GZ š
EDIT: for future reference please use my real name Alexander Jonkeren (in accordance with Zooniverse guidelines)) instead of my fantasy account name, thanks in advance
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