Starship Asterisk*

[quote=Ann post_id=313341 time=1621313574 user_id=129702]
I read somewhere that NGC 4565 would look like M100 if we could see it face on.
Ann
[/quote]
[img2]https://scontent.fhel4-1.fna.fbcdn.net/v/t1.6435-9/187150378_3933367573450991_5776737793213465136_n.jpg?_nc_cat=108&ccb=1-3&_nc_sid=dbeb18&_nc_eui2=AeHJ6wWvZPvNyGc7o_NRwwhISfd4c99IhoNJ93hz30iGg8P82eXoIh-5LtSpHKxCMBLFD-yWPlU8vEiedISrfyZJ&_nc_ohc=0h2Kbifd82EAX-FGQFE&_nc_ht=scontent.fhel4-1.fna&oh=e6e50301011c85021b8c72186fd18e87&oe=60C8D5B3[/img2]

[float=left][img3="NGC 4565. Photo: Ken Crawford."]https://upload.wikimedia.org/wikipedia/commons/thumb/2/2c/Needle_Galaxy_4565.jpeg/1024px-Needle_Galaxy_4565.jpeg[/img3][/float][float=right][img3="M100 and surrounding field. Image: SDSS/Giuseppe Donatiello."]https://upload.wikimedia.org/wikipedia/commons/thumb/c/cf/M100_group_%2828104666950%29.jpg/1280px-M100_group_%2828104666950%29.jpg[/img3][/float]

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I read somewhere that NGC 4565 would look like M100 if we could see it face on.

Well, that's possible. Or not. Because no two spiral galaxies look the same. And personally, I'm convinced that the disk of NGC 4565 is (much) larger than the disk of M100.

But both these galaxies are large and "calm", so I guess they have something in common.

Ann

image very interesting

[quote=VictorBorun post_id=313328 time=1621267167 user_id=145500]
[quote="Chris Peterson" post_id=313320 time=1621261094 user_id=117706]
Try it again, but from just a degree or two off the edge.
[/quote]

[img2]https://scontent.fhel4-1.fna.fbcdn.net/v/t1.6435-9/186634608_3931328400321575_4951243483245723448_n.jpg?_nc_cat=101&ccb=1-3&_nc_sid=dbeb18&_nc_eui2=AeFUOEJ6tTF8BWKIxM_mKWU5ueGew6jdrou54Z7DqN2uizDkpjpKlDCVRtrk6c0RT1uX8_pWPNDHKR00ie1-X6ME&_nc_ohc=VsTLhWwMdvsAX-Txgn-&_nc_ht=scontent.fhel4-1.fna&oh=d7801b670c909c7c1edbe1f8ee5fd16b&oe=60C84421[/img2]
[img2]https://scontent.fhel4-1.fna.fbcdn.net/v/t1.6435-9/186544429_3931335646987517_205136925322464382_n.jpg?_nc_cat=108&ccb=1-3&_nc_sid=dbeb18&_nc_eui2=AeH6ZkB84ydwU0QJIatGXXXBJ2k7viLGiBUnaTu-IsaIFWW3UVlJUWgcIPzG5g8PSJLKfnFBt4GmycJb73tJd2pp&_nc_ohc=XX5ubLigczkAX9za_cd&_nc_ht=scontent.fhel4-1.fna&oh=17abe1af236105ba648edc80315913ec&oe=60C69E51[/img2]
[/quote]

The coins on the right are basically what we see with this galaxy. (All the more confused by the fact that the galaxy isn't perfectly flat, so we have obscuring material along the edge.

[quote="Chris Peterson" post_id=313320 time=1621261094 user_id=117706]
Try it again, but from just a degree or two off the edge.
[/quote]

[img2]https://scontent.fhel4-1.fna.fbcdn.net/v/t1.6435-9/186634608_3931328400321575_4951243483245723448_n.jpg?_nc_cat=101&ccb=1-3&_nc_sid=dbeb18&_nc_eui2=AeFUOEJ6tTF8BWKIxM_mKWU5ueGew6jdrou54Z7DqN2uizDkpjpKlDCVRtrk6c0RT1uX8_pWPNDHKR00ie1-X6ME&_nc_ohc=VsTLhWwMdvsAX-Txgn-&_nc_ht=scontent.fhel4-1.fna&oh=d7801b670c909c7c1edbe1f8ee5fd16b&oe=60C84421[/img2]
[img2]https://scontent.fhel4-1.fna.fbcdn.net/v/t1.6435-9/186544429_3931335646987517_205136925322464382_n.jpg?_nc_cat=108&ccb=1-3&_nc_sid=dbeb18&_nc_eui2=AeH6ZkB84ydwU0QJIatGXXXBJ2k7viLGiBUnaTu-IsaIFWW3UVlJUWgcIPzG5g8PSJLKfnFBt4GmycJb73tJd2pp&_nc_ohc=XX5ubLigczkAX9za_cd&_nc_ht=scontent.fhel4-1.fna&oh=17abe1af236105ba648edc80315913ec&oe=60C69E51[/img2]

[quote=Ann post_id=313315 time=1621255482 user_id=129702]...
Well, I couldn't find anything I liked by Twisted Sister. Sorry!
[/quote]
[size=120][b][i]Twisted Sister - We're Not Gonna Take It[/i][/b][/size]
[youtube]https://www.youtube.com/watch?v=4xmckWVPRaI[/youtube]

[quote=VictorBorun post_id=313319 time=1621260454 user_id=145500]
[quote="Chris Peterson" post_id=313318 time=1621257595 user_id=117706]
The galaxy isn't a disk, but a cylinder. Take a picture of a coin from edge-on and try to optically rotate it!
[/quote]

Yes, the edge of a coin gets thicker at the observer's side.
[img2="https://scontent.fhel4-1.fna.fbcdn.net/v/t1.6435-9/186999013_3931050620349353_3744287813771020212_n.jpg?_nc_cat=107&ccb=1-3&_nc_sid=dbeb18&_nc_eui2=AeGvO7eVquM2RgygdavaLRU9CGYy51zAMEwIZjLnXMAwTJ5e7uIB2ymvAAwopAG_srEfPQlLbsWe1v_qWKnui6Uo&_nc_ohc=O1Z9SeXvEBUAX8Li-YT&_nc_oc=AQkqW3jEZBmzROQRXgkf1vFCCeqqPM3EQUj7z5LWFWtmf6f-lyE3TaVn6A9czKY2x0k&_nc_ht=scontent.fhel4-1.fna&oh=edd35e448eb339042e8d53d5af089a8f&oe=60C7F819"]original (alas with some perpective effect)
[img2="https://scontent.fhel4-1.fna.fbcdn.net/v/t1.6435-9/186535827_3931052663682482_625979817558640104_n.jpg?_nc_cat=111&ccb=1-3&_nc_sid=dbeb18&_nc_eui2=AeFBwxiqgAoSKfW4uqBxTF2hjk4dYRusvMWOTh1hG6y8xWFHzRVMJnOTJUdlc78CDiOIOhuFp2SSaq7NlKFE4r-1&_nc_ohc=No6zfX53_vwAX8bUE6a&_nc_ht=scontent.fhel4-1.fna&oh=415d777f407d2d4b8d9a694846ecd386&oe=60C6CBD2"]compressed perpendicular to the line of view
[/quote]

Try it again, but from just a degree or two off the edge. Your examples are far from "edge-on".

[quote="Chris Peterson" post_id=313318 time=1621257595 user_id=117706]
The galaxy isn't a disk, but a cylinder. Take a picture of a coin from edge-on and try to optically rotate it!
[/quote]

Yes, the edge of a coin gets thicker at the observer's side.
[img2="https://scontent.fhel4-1.fna.fbcdn.net/v/t1.6435-9/186999013_3931050620349353_3744287813771020212_n.jpg?_nc_cat=107&ccb=1-3&_nc_sid=dbeb18&_nc_eui2=AeGvO7eVquM2RgygdavaLRU9CGYy51zAMEwIZjLnXMAwTJ5e7uIB2ymvAAwopAG_srEfPQlLbsWe1v_qWKnui6Uo&_nc_ohc=O1Z9SeXvEBUAX8Li-YT&_nc_oc=AQkqW3jEZBmzROQRXgkf1vFCCeqqPM3EQUj7z5LWFWtmf6f-lyE3TaVn6A9czKY2x0k&_nc_ht=scontent.fhel4-1.fna&oh=edd35e448eb339042e8d53d5af089a8f&oe=60C7F819"]original (alas with some perpective effect)
[img2="https://scontent.fhel4-1.fna.fbcdn.net/v/t1.6435-9/186535827_3931052663682482_625979817558640104_n.jpg?_nc_cat=111&ccb=1-3&_nc_sid=dbeb18&_nc_eui2=AeFBwxiqgAoSKfW4uqBxTF2hjk4dYRusvMWOTh1hG6y8xWFHzRVMJnOTJUdlc78CDiOIOhuFp2SSaq7NlKFE4r-1&_nc_ohc=No6zfX53_vwAX8bUE6a&_nc_ht=scontent.fhel4-1.fna&oh=415d777f407d2d4b8d9a694846ecd386&oe=60C6CBD2"]compressed perpendicular to the line of view

[quote=VictorBorun post_id=313305 time=1621235172 user_id=145500]
If the Needle Galaxy is a disk seen at 87.25°, then face on it is this disk (Earth-based observer's line is upward, so the dust ring is better seen at the top of the picture, backlighted by the core)

A pair of blue arms must be real and bright jets from the core are just artifacts of stretching the globe core image
[/quote]

You can't optically correct an edge-on galaxy into a face-on view. The galaxy isn't a disk, but a cylinder. Take a picture of a coin from edge-on and try to optically rotate it!

This is very clearly a fairly typical spiral galaxy, without jets. Viewed face on it would appear circular with spiral arms and a bright center.

[float=left][img3="NGC 4565. Source: https://spacepix.wordpress.com/2015/08/25/ngc-4565-needle-galaxy-april-15-2015/"]https://spacepix.files.wordpress.com/2015/05/3-17-2015-ngc-4565.jpg?w=479&h=311[/img3][/float][float=right][attachment=0]NGC 891 MassimoTuninetti.png[/attachment][c][size=85][color=#0040FF]NGC 891. Photo: Massimo Tuninetti.[/color][/size][/c][/float]

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What, the Color Commentator is posting a picture of NGC 4565 in black and white? Yes, because I wanted to emphasize how extremely long and thin the disk of this galaxy really is. Compare it with the similarly edge-on galaxy NGC 891, whose disk looks (and is, I'm sure) much smaller. Admittedly, the pictures aren't directly comparable, because they have been taken with different cameras, filters and exposure times, and they have been processed differently. Even so, the disk of NGC 4565 really [i][b]is[/b][/i] very flat and extensive!


[float=left][img3="NGC 4565, an edge on galaxy with little star formation. Photo: Ken Crawford. "]https://upload.wikimedia.org/wikipedia/commons/thumb/2/2c/Needle_Galaxy_4565.jpeg/1024px-Needle_Galaxy_4565.jpeg[/img3][/float][float=right][img3="Starburst edge on galaxy NGC 4631. Photo: R. Jay GaBany."]https://www.cosmotography.com/images/gabany-small_NGC4631_with_stream_and_new_satellites.jpg[/img3][/float]

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NGC 4565 seems extremely "calm and undisturbed" to me. Nothing much is bothering this galaxy, which is why its disk has been able to grow so vast. And nothing much is happening "from within", either. There is not a lot of star formation going on in this "island universe". Compare the appearance of NGC 4565 with that of starburst galaxy NGC 4631. The difference is certainly striking!


There is the slightest hint of a warp in the huge disk of NGC 4565. That reminds me of a few other galaxies with warped disks:


[float=left][img3="ESO 510-G13, a 'twisted sister galaxy' of the Milky Way. Photo: Hubble."]https://www.universetoday.com/wp-content/uploads/2011/04/twisted-sister-galaxy.jpg[/img3][/float][float=right][img3="Twisted Milky Way. I think they borrowed the bulge of NGC 4565 to serve as a a proxy for the bulge of the Milky Way. Maybe they used the disk of NGC 4565 too, and just twisted it a little? Illustration: OGLE/Warsaw University."]https://ichef.bbci.co.uk/news/976/cpsprodpb/122C1/production/_108133447_de27.jpg[/img3][/float]

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So here we have both the Needle galaxy (NGC 4565) and the Twisted Sister (ESO 510-G13). So let's listen to "A needle pulling thread" from Sound of Music, and.... Well, I couldn't find anything I liked by Twisted Sister. Sorry!


[float=left][youtube]https://www.youtube.com/watch?v=1RW3nDRmu6k[/youtube][c][size=85]Sew, a needle pulling thread.[/size][/c][/float] [float=right][img3="Twisted Sister. Sorry, they've been censored."]http://www.oif.ala.org/oif/wp-content/uploads/2018/04/censored-1726364_1280.jpg[/img3][/float]

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Ann

[attachment=0]NGC4565_CFHT_960.jpg[/attachment]


NGC 4565; The Needle Galaxy really has nice clean linrs!


..

[quote=Ann post_id=313306 time=1621243688 user_id=129702]
[float=left]NGC 4565 in Guide.png[/float]
This is what NGC 4656 looks like in my trusted software Guide.
Ann
[/quote]

Seems like the Needle Galaxy proved too much of a needle for this software.
I mean, the visible ellipse of the disk is more narrow than the visible globe of the core.
This case is out of the ordinary.

a disk seen at 87.25° is in lime color:
[img2="https://scontent.fhel4-1.fna.fbcdn.net/v/t1.6435-9/186528864_3930603017060780_1200425237716507092_n.jpg?_nc_cat=107&ccb=1-3&_nc_sid=dbeb18&_nc_eui2=AeE5uzxFmvR4mSzkwUUTZHxhTtgTSN4qGFdO2BNI3ioYV6n1gtUZCI5gB5xN1fd-mG2YpT3YRPZBPXeAnESPmhLh&_nc_ohc=a722rdqwH0oAX_iJzLS&_nc_ht=scontent.fhel4-1.fna&oh=09f0ac194860d36fe4d0ad233a7ab5e0&oe=60C78FB1"]

[float=left][attachment=0]NGC 4565 in Guide.png[/attachment][/float]

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This is what NGC 4656 looks like in my trusted software Guide.

I trust Guide to show me the correct inclination of galaxies.

Ann

[quote=shaileshs post_id=313303 time=1621229920 user_id=143908]
[quote=VictorBorun post_id=313299 time=1621226246 user_id=145500]
I wonder why every encyclopedia is shy to tell the angle of this galaxy disk to our line of view.
[/quote]

I found these 2 pages which say it's approx. 87-88 deg tilted -

1) http://www.nightskyinfo.com/archive/ngc4565/
"NGC 4565 is inclined to an angle of 87°, 3° from edge-on."

2) https://academic.oup.com/mnras/article/427/4/2797/971155
"For the inclination, we find a best-fitting value of ∼87°.25, which is in agreement with earlier reported results. Indeed, H I observations of the gaseous disc in the past have constrained the inclination >84° (Ruben 1991), with more recent H I observations reporting an inclination angle of 87°.5 (Zschaechner et al. 2012). From a similar radiative transfer study, Alton et al. (2004) estimated an inclination of 88°."

Hope that helps..
[/quote]

If the Needle Galaxy is a disk seen at 87.25°, then face on it is this disk (Earth-based observer's line is upward, so the dust ring is better seen at the top of the picture, backlighted by the core)

A pair of blue arms must be real and bright jets from the core are just artifacts of stretching the globe core image

[img2="https://scontent.fhel4-1.fna.fbcdn.net/v/t1.6435-9/186561524_3930210290433386_7775827635921504806_n.jpg?_nc_cat=111&ccb=1-3&_nc_sid=dbeb18&_nc_eui2=AeEP7uZA-cJ4mbWR67p2zoRDfC1E6Cdykg18LUToJ3KSDecBHyhD6vc1ZfUUdL8LVBBTVPn7o0-P5-p9CiMtWiW7&_nc_ohc=Y_YMyxfqcbgAX8QGYPd&_nc_ht=scontent.fhel4-1.fna&oh=b705a25a1fe3e64a42bbd8b5592ee158&oe=60C75927"][/img2]

[quote=VictorBorun post_id=313299 time=1621226246 user_id=145500]
I wonder why every encyclopedia is shy to tell the angle of this galaxy disk to our line of view.
[/quote]

I found these 2 pages which say it's approx. 87-88 deg tilted -

1) http://www.nightskyinfo.com/archive/ngc4565/
"NGC 4565 is inclined to an angle of 87°, 3° from edge-on."

2) https://academic.oup.com/mnras/article/427/4/2797/971155
"For the inclination, we find a best-fitting value of ∼87°.25, which is in agreement with earlier reported results. Indeed, H I observations of the gaseous disc in the past have constrained the inclination >84° (Ruben 1991), with more recent H I observations reporting an inclination angle of 87°.5 (Zschaechner et al. 2012). From a similar radiative transfer study, Alton et al. (2004) estimated an inclination of 88°."

Hope that helps..

[quote=VictorBorun post_id=313299 time=1621226246 user_id=145500]
I wonder why every encyclopedia is shy to tell the angle of this galaxy disk to our line of view.
[/quote]

Isn't it rather obvious?

I wonder why every encyclopedia is shy to tell the angle of this galaxy disk to our line of view.

[url=https://apod.nasa.gov/apod/ap210517.html] [img]https://apod.nasa.gov/apod/calendar/S_210517.jpg[/img] [size=150]NGC 4565: Galaxy on Edge[/size][/url]

[b] Explanation: [/b] Is our Milky Way Galaxy this thin? Magnificent spiral galaxy [url=http://www.messier.seds.org/xtra/ngc/n4565.html]NGC 4565[/url] is viewed edge-on from planet Earth. Also known as the [url=https://en.wikipedia.org/wiki/NGC_4565]Needle Galaxy[/url] for its narrow profile, bright [url=https://www.eso.org/public/images/eso0525a/]NGC 4565[/url] is a stop on many telescopic tours of the northern sky, in the faint but well-groomed constellation [url=http://www.dibonsmith.com/com_con.htm]Coma Berenices[/url]. [url=https://www.cfht.hawaii.edu/HawaiianStarlight/AIOM/English/CFHT-Coelum-AIOM-Jun2018.html]This sharp, colorful image[/url] reveals the spiral galaxy's [url=https://arxiv.org/abs/1810.10073]boxy, bulging[/url] central core cut by [url=https://www.nasa.gov/mission_pages/hubble/science/needle-edge.html]obscuring dust lanes[/url] that lace NGC 4565's thin galactic plane. An [url=https://i.pinimg.com/originals/79/d9/c0/79d9c0f52cba7d33aeb90ff6b6db07b8.jpg]assortment[/url] of other [url=https://apod.nasa.gov/apod/ap200726.html]background galaxies[/url] is included in the pretty field of view. Thought similar in shape to our own [url=https://astronomy.swin.edu.au/cosmos/M/Milky+Way]Milky Way Galaxy[/url], NGC 4565 lies about 40 million [url=https://chandra.harvard.edu/photo/cosmic_distance.html]light-years[/url] distant and spans some 100,000 light-years. Easily spotted with small telescopes, [url=https://apod.nasa.gov/apod/ap040808.html]sky enthusiasts[/url] consider NGC 4565 to be a prominent celestial masterpiece [url=https://apod.nasa.gov/apod/ap080419.html]Messier missed[/url].


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