APOD: NGC 6872: A Stretched Spiral Galaxy (2016 Apr 26)

[starsurfer]

I'd really like it if Judy Schmidt processed some of the many PN there are data for in the ESO archive. Her processing and aesthetic sensibilities are well balanced and really good for lack of words.

[geckzilla]

I'm right here, you know! You can speak to me directly instead of in third person.

I never got the hang of ESO's archive. The interface is, imo, inferior to the Hubble Legacy Archive, at least as far as simple browsing goes. There are no thumbnails so when you're not sure what you're looking for it's pretty painful to deal with. I did some mass downloading and then would find maybe 1 or 2 nice things in there after some exhaustive searching.

[geckzilla]

So I poked around a bit more with the GALEX data because it's fun and I wondered if my eyes were deceiving me or if it was perhaps some kind of quirk of the detector, but I noticed this faintly visible connection between NGC 6872 and its neighboring elliptical NGC 6876. I looked for any other study by other observatories and there was a notable connection between the two seen by astronomers using data from XMM-Newton. So it's not far-fetched to suppose that this faint connection is also observed by GALEX. Here's a pic.

Possible bridge between NGC6872 and NGC6876

[Ann]

So I poked around a bit more with the GALEX data because it's fun and I wondered if my eyes were deceiving me or if it was perhaps some kind of quirk of the detector, but I noticed this faintly visible connection between NGC 6872 and its neighboring elliptical NGC 6876. I looked for any other study by other observatories and there was a notable connection between the two seen by astronomers using data from XMM-Newton. So it's not far-fetched to suppose that this faint connection is also observed by GALEX. Here's a pic.

GALEX_NGC6872-NGC6876.jpg

Fascinating picture, Geck. I love the GALEX images, and I'm really sorry that GALEX is now defunct, and that there is no other telescope photographing galaxies in ultraviolet light. Well, the Hubble does sometimes, but it mostly photographs its targets in far infrared (814 nm) and either yellow-green (555 nm) or orange (616 nm) light. Okay, maybe I got those figures a few nanometers wrong, but basically Hubble doesn't photograph most of its targets in ultraviolet light.

NGC 6872 looks so striking in the GALEX image you posted, and so different from the other galaxies in the group. Even so I must insist that NGC 6872 is a moderately red spiral galaxy, which is obvious from its large bulge and yellowish bright inner arms. I checked the B-V index of NGC 6876, the large elliptical neighbor of NGC 6872, and NGC 6876 isn't that much redder than elongated NGC 6872: its B-V is 1.03 versus 0.92 for NGC 6872. That is not a negligible difference, but it isn't huge. And yet, in ultraviolet light they look so totally different.

NGC 6872 is clearly "fluffy" with its extremely long outstretched arms. It is perhaps not surprising that there should be a bridge of material between (in particular) the fluffiest arm of NGC 6872 and the (likely very massive) elliptical galaxy NGC 6876. But if it isn't surprising, it is sure fascinating to see it.

Thanks for finding and posting that image, Geck!

Ann

[geckzilla]

far infrared (814 nm) and either yellow-green (555 nm) or orange (616 nm) light. Okay, maybe I got those figures a few nanometers wrong, but basically Hubble doesn't photograph most of its targets in ultraviolet light.

F814W is a broad, near infrared filter, and when you said 616 you were probably referring to F606W. ...Close enough with that last one. We'll see far infrared with JWST, assuming all goes as planned.

[star struk]

spiral galaxy appearing next to ngc 6872 needs to be studied further

[rstevenson]

spiral galaxy appearing next to ngc 6872 needs to be studied further

I'm sure that can be arranged. Payment is accepted via PayPal or electronic bank transfer.

Rob

[starsurfer]

I'm right here, you know! You can speak to me directly instead of in third person.

I never got the hang of ESO's archive. The interface is, imo, inferior to the Hubble Legacy Archive, at least as far as simple browsing goes. There are no thumbnails so when you're not sure what you're looking for it's pretty painful to deal with. I did some mass downloading and then would find maybe 1 or 2 nice things in there after some exhaustive searching.

Oops I'm sorry, I forgot that both of you are the same person!
Also I've not been sleeping well lately.

I've found the ESO archive quite straightforward and easy to use and found lots of great quality data!

[geckzilla]

I've found the ESO archive quite straightforward and easy to use and found lots of great quality data!

It's fine if you already know what you're looking for. Otherwise, it's terrible. With the HLA I can just browse thumbnails and pick up something that looks intriguing. You can see the target name in ESO's archive, but you have to look each one up, and usually they are like... IRAS012938-987.32 which is both useful and incredibly unhelpful at the same time.

[starsurfer]

I've found the ESO archive quite straightforward and easy to use and found lots of great quality data!

It's fine if you already know what you're looking for. Otherwise, it's terrible. With the HLA I can just browse thumbnails and pick up something that looks intriguing. You can see the target name in ESO's archive, but you have to look each one up, and usually they are like... IRAS012938-987.32 which is both useful and incredibly unhelpful at the same time.

It's true that it is only effective when you know what you want to look up. If you're interested, do you want a list of planetary nebulae I could PM you?

[geckzilla]

I've found the ESO archive quite straightforward and easy to use and found lots of great quality data!

It's fine if you already know what you're looking for. Otherwise, it's terrible. With the HLA I can just browse thumbnails and pick up something that looks intriguing. You can see the target name in ESO's archive, but you have to look each one up, and usually they are like... IRAS012938-987.32 which is both useful and incredibly unhelpful at the same time.

It's true that it is only effective when you know what you want to look up. If you're interested, do you want a list of planetary nebulae I could PM you?

Do you have that kind of list that can just be uploaded to the form?