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Arp 214, Arp 322, and distant relatives


wimvb

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Ngc 3718 is a warped galaxy in the constellation Ursa Major. It is at a distance of approximately 50 Mly from earth. The galaxy has number 214 in Arp's catalogue of peculiar galaxies.
Also in this field of view is ngc 3729, which may be interacting with ngc 3718, causing the warped structure in the latter. This interaction has led to the high rate of star formation in the outer arms of the main galaxy, giving them a blue appearance.

There is a multitude of galaxies in this image, among others LEDA 2432563, just to the upper left of ngc 3718. This small galaxy has a redshift of 0.178, which puts it at a distance of 2500 Mly. Some of the smaller ones in the area are at a distance of up to 3 500 Mly.

The small galaxy group just below ngc 3718 is Hickson compact group 56, aka Arp322. The members of this group all have a similar red shift of 0.0265 - 0.0270, which puts them at about 350 Mly from earth. Some sources quote 400 Mly. That's 7 - 8 times further away than ngc 3718.

Acquisition details:

telescope: MN190 DS on AZEQ6-GT with ZWO off axis guider

camera: ZWO ASI174MM-Cool with ZWO lrgb filters

Software: Ekos/Kstars, PHD2 and PixInsight

Total integration time: 15 hours (6 hrs Luminance) over about four nights February/March 2020

ngc3718_LRGB_2.thumb.png.759021b740b5d5eb548764e8cffd5741.png

(click on the image for a larger version)

Edited by wimvb
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Great image @wimvb especially on Arp 214 and the detail running through the structure.  Nice to see these different galaxies.

Given your scope and camera, I guess the size is quite small? (not sure if any cropping has been done) - under 10 arc minutes or am I way off?

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2 minutes ago, geeklee said:

Great image @wimvb especially on Arp 214 and the detail running through the structure.  Nice to see these different galaxies.

Given your scope and camera, I guess the size is quite small? (not sure if any cropping has been done) - under 10 arc minutes or am I way off?

Thanks, Lee.

ngc 3718 has a largest diameter of 5.13 arcminutes. But this size is debatable, because faint arms may reach further than what is given in eg Wikipedia.

My camera has a small sensor, and this image has only stacking edges cropped. I cropped a little more than usual, because the data from one night was misaligned. My sensor is 1936 x 1216 pixels

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Here's an annotated version. I'm not at all certain about the correctness.

(Annotated in PixInsight, with added labels from Aladin)

ngc3718_RGB_2_Annotated.thumb.png.4b8bdf55caf6c2e6ad654a8c1403f682.png

Apparently, there are at least two quasars in this image, one (J113447.9+530515) with a reported redshift of 0.53807, and the other (J113459.08+531106.1)with z = 1.258929. But that can't be right, can it?

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1 minute ago, gorann said:

Yes, very nice image Wim! There seem to be some violent interactions going on among the galazies "on a string" just below NGC 3718.

Thanks, Göran.

Yes, it seems so. But I would need a few meter more focal length to see this clearer. Now if only I knew someone who could help .... 😋

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3 minutes ago, wimvb said:

Thanks, Göran.

Yes, it seems so. But I would need a few meter more focal length to see this clearer. Now if only I knew someone who could help .... 😋

That is actually not a bad idea Wim! See what I can do over the coming clear nights. However my 3.55 m FL Meade with the full frame Sony A7s has the same field of view as your set up, but it may still catch more details.

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1 minute ago, gorann said:

but it may still catch more details.

3.5 times the focal length and only 1.4 times the pixel size. Your pixel scale should be 0.49 "/pixel, I believe. (I have 1.2) And you have better guiding rms. If seeing is good, you should be able to pull more out of this.

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13 minutes ago, don4l said:

I love these ARP galaxies, and this image makes me hungry to image some.

Below the main galaxy is Hickson compact group 56, aka Arp322. Two Arps for the price of one.

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14 minutes ago, wimvb said:

Below the main galaxy is Hickson compact group 56, aka Arp322. Two Arps for the price of one.

If the current forecast is correct (unlikely) then I might be able to have a look at them in a couple of nights. 

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