Fabio,
I think that you have found something
very interesting in your image. I will have to find out by checking the literature of professional astronomy whether or not it qualifies as a discovery. I suspect that the outer Very Faint optical material in N2841 was already known by professional astronomers, but its structure and properties may not be well understood.
Your imaging effort is part of a trend in amateur astronomy in which increasing numbers of amateurs image deep enough to find new things in the outermost regions of galaxies.
The unusual outermost optically-luminous material in
NGC 2841 is very faintly and indistinctly visible in many amateur images, but most images are
not deep enough to show the
detailed structure of this "anomalous outermost material".
There is only one other image I know about that shows this Anomalous Outermost Material properly. This is the image by
CXIELO Observatory. See this URL:
http://www.cxielo.ch
While the disk structures of spiral and S0 galaxies are
approximately planar, it is very very common to find that spiral and S0 galaxies have bends, warps, and tilts, in their outer regions.
In the professional literature, any obvious bending away from the principal plane of a disk galaxy is called a Warp.
The amazing thing about warps is firstly that there are many different kinds, and secondly that the large variety of observed non-planar phenomena is
not understood by professional astronomers.
In the last two years I have been undertaking a detailed study of non-planar phenomena in disk galaxies. Based on this experience, there are
at least two possible interpretations of what is seen at the two ends of the major axis of NGC 2841, in your super-stretched image. The
three-dimensional structure of this galaxy, at the extreme ends of the major axis could be as follows:
(1) There could be two bends of the "planar" disk, away from the principal plane of the galaxy, at the two extreme ends of the major axis, with the two bends being oppositely directed.
(2) The entire Faint outermost part (annulus) of this galaxy could be a ring which is at an angle to the ring that is the bright part of this galaxy. In other words, the inner bright galaxy would be at one position angle and the the outer faint part of this galaxy could be at another position angle. Thus, NGC 2841 might occupy two planes, rather than one.
I should point out to you that neither of these two types of bends and tilts is a rare phenomenon, in the population of spiral galaxies.......
In particular, oppositely directed bends/warps at the two extreme ends of the major axis of a galaxy are
very common; for instance M31 and our own Galaxy have this sort of warp!
Howevever this is not to say that anybody really understands what causes this sort of phenomenon.
In the professional literature, there has been some limited study of the two-sided warps and bends, but there has been very little study of what could cause a spiral galaxy to occupy more than one plane.
I fact, a good number of individual spiral and S0 galaxies only make sense if they are modelled as being composed of a number of different rings (planes) at various angles to each other .
(Note: It is actually very tricky to figure out the
3-dimensional structure of a galaxy from its 2-dimensional image; there is no easy way to do this......)
The Unusual Outermost Material in N2841 is also visible in the ultraviolet image taken by the GALEX satellite, which I attach.
In this image, far-ultraviolet light displays as blue and near-ultraviolet light displays as Yellow :
In this ultraviolet image, there is plenty of blue light visible outside the bright optical body of N2841, that is, there is far-ultraviolet emission here. In the outer regions of galaxies, this FUV emission can only come from young & luminous OB stars; so there is recent star-formation happening here.
________________
I have just found a radio (21cms) image of the HI (cold neutral atomic hydrogen) layer in NGC 2841, and this confirms that there is a bend or tilt away from the plane of this galaxy:
This 21 cm wavelength image of the cold Hydrogen Gas layer in this galaxy is taken from The HI Nearby Galaxy Survey, and intensity of the grayscale corresponds to the amount of hydrogen gas in the line-of-sight.
The bright inner disk of gas corresponds in space to the bright optical disk of NGC 2841 , but
note how the outer gas is at a different position angle. It looks more like the entire outermost part of this galaxy is at a different position angle to the inner part, and that this galaxy occupies two distinct planes!! Alternately, the gas layer is bent away from the principal plane, at the two ends of the major axis.
cheers,
madbadgalaxyman
