Author Topic: What do you think about this one ??..  (Read 2776 times)

AlexandredOr

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What do you think about this one ??..
« on: December 22, 2013, 07:38:51 pm »
Already classified as merger (similar z : 0.015844 and 0.015971)... But I see no distorsion, no sign of mergering galaxies. Do you think, as I do, that overlap is correct ??
1237657594608615660  UGC 03995


Moreover I think this image could be in the top 10 of the most beautiful overlaps !

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JeanTate

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Re: What do you think about this one ??..
« Reply #1 on: December 23, 2013, 11:55:39 am »
I agree, overlap not merger. And yes, it's really spectacular, whether merger or overlap.

What is NGC3314's opinion?

AlexandredOr

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Re: What do you think about this one ??..
« Reply #2 on: December 23, 2013, 10:38:07 pm »
Thank you Jean for your comment !

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zutopian

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Re: What do you think about this one ??..
« Reply #3 on: December 31, 2013, 09:05:49 am »
I agree, overlap not merger. And yes, it's really spectacular, whether merger or overlap.

What is NGC3314's opinion?

There is a new "Object of the Day" by him, where he presents a new paper and that GPair shows up there.:
http://www.galaxyzooforum.org/index.php?topic=281543.msg648519#new



AlexandredOr

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Re: What do you think about this one ??..
« Reply #4 on: December 31, 2013, 10:12:26 am »
Great minds encounter  ::) ::) ::)

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zutopian

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Re: What do you think about this one ??..
« Reply #5 on: December 31, 2013, 05:31:19 pm »
I agree, overlap not merger. And yes, it's really spectacular, whether merger or overlap.

What is NGC3314's opinion?

There is a new "Object of the Day" by him, where he presents a new paper and that GPair shows up there.:
http://www.galaxyzooforum.org/index.php?topic=281543.msg648519#new

Besides there is following paper about the same GPair.:

The Occulting Galaxy Pair UGC 3995; Dust properties from HST and CALIFA data
B.W. Holwerda (ESA-ESTEC), W.C. Keel (University of Alabama)
(Submitted on 23 May 2013)
http://arxiv.org/abs/1305.5358

Jean had informed about it in following topic.:
http://www.galaxyzooforum.org/index.php?topic=280968.msg635360#msg635360


« Last Edit: December 31, 2013, 05:42:25 pm by zutopian »

zutopian

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Re: What do you think about this one ??..
« Reply #6 on: June 03, 2014, 12:21:04 pm »
Warning: this topic has not been posted in for at least 120 days.

Here is a similiar case. Copy from another topic.:

1237659327100158111


Z 0.04417 and 0.04418

DR7 ID 588011101034774582 was posted in this topic before!
It is is listed in the GZ overlap catalog.

Searching with 1237659327100158111 nothing came up.
But me, everybody think that it's an overlap ??

The DR7 ID was posted in this topic before.: DR7 and DR8/9/10 have different objIDs for the same objects. All DR7 objects are also availabe in DR8/9/10, but some objects are new in DR8/9/10.
It is a "dumbbell system".: The image is presented in below paper.: on page 6 in Fig. 8:
 
Active Galactic Nucleus Pairs from the Sloan Digital Sky Survey. I. The Frequency on ~ 5-100 kpc Scales
Xin Liu, Yue Shen, Michael A. Strauss, Lei Hao
Quote
In addition, we excluded ten “dumbbell” systems (e.g., Valentijn & Casertano 1988), which have double nuclei in a single host galaxy, but show no optical tidal features indicative of ongoing interactions between the two nuclei. Figure 8 shows six such examples.
(Submitted on 5 Apr 2011 (v1), last revised 14 Jul 2011 (this version, v2))
http://arxiv.org/abs/1104.0950

« Last Edit: June 03, 2014, 12:29:44 pm by zutopian »

NGC3314

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Re: What do you think about this one ??..
« Reply #7 on: June 04, 2014, 12:14:53 am »
As I stare at this one, I suspect the later processing might show it a big more clearly than the DR7 jpeg version. I cant quite trace two sets of symmetric, undisturbed spiral arms, so I'd suspect an interaction at this point. he foreground galaxy looks like there is one major arm winding outward, something vanishingly rare in isolated galaxies. Still, that dust lane is so nicely silhouetted, and it shows an interesting offset between the peak of starlight and dust attenuation in that arm.

Thanks for pointing out the "dumbbell" systems in Liu et al. I've seen the paper but missed this subset of their galaxy list.

zutopian

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Re: What do you think about this one ??..
« Reply #8 on: June 04, 2014, 06:44:33 am »
As I stare at this one, I suspect the later processing might show it a big more clearly than the DR7 jpeg version. I cant quite trace two sets of symmetric, undisturbed spiral arms, so I'd suspect an interaction at this point. (...)

Although you think, that there actually seems to be interaction, it is listed in the GZ overlap catalog. I wonder why? Do I miss something?

« Last Edit: June 04, 2014, 09:58:16 am by zutopian »

NGC3314

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Re: What do you think about this one ??..
« Reply #9 on: June 04, 2014, 12:55:23 pm »
As I stare at this one, I suspect the later processing might show it a big more clearly than the DR7 jpeg version. I cant quite trace two sets of symmetric, undisturbed spiral arms, so I'd suspect an interaction at this point. (...)

Although you think, that there actually seems to be interaction, it is listed in the GZ overlap catalog. I wonder why? Do I miss something?

Quote from: NGC3314
I suspect the later processing might show it a big more clearly than the DR7 jpeg version.

It's stronger than that - checking back on the DR7 and DR10 versions, some of the spiral structure is much more clearly shown in the later image, and I see now that it was actually re-observed with better seeing. The splitting of the arm just NW of the W nucleus is now clear and wasn't earlier. I can update my working file, which I plan to put online when we have worked through Hubble Zoo overlaps for comparison.

zutopian

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Re: What do you think about this one ??..
« Reply #10 on: June 04, 2014, 01:32:16 pm »
I guess, that you mean, that the DR7 and DR10 images look different because of different image processing techniques.: The spiral arms are more dinstinct on the DR10 image. Besides the dustlane isn't visible in DR7. As far as I know, the image, which is presented in the Liu et. al paper is the DR7 image.

Here is the DR7 image.:                                                                Here is the DR10 image.:


« Last Edit: June 04, 2014, 01:36:25 pm by zutopian »

NGC3314

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Re: What do you think about this one ??..
« Reply #11 on: June 04, 2014, 01:44:12 pm »
That's what I first thought when I looked at the new image, but looking at the metadata, the DR10 image is from a different observation on a different date (so the image quality seems to have actually been better, not just the processing for display). Using the MJD (modified Julian date) of the observations, for DR7 it gives
mjd_r   52046.3104
and for DR10,
mjd_r   52434.2570627

so the two data sets were taken 388 days apart.


zutopian

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Re: What do you think about this one ??..
« Reply #12 on: June 10, 2014, 12:27:04 pm »
Another GPair: It is listed in the GZ overlap catalog, but it also had been one of the GPairs in the Merger Zoo.: 


http://cas.sdss.org/dr7/en/tools/explore/obj.asp?id=587736941981466667