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Old 16-02-2013, 07:51 PM
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madbadgalaxyman (Robert)
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Join Date: Mar 2011
Location: Brisbane
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BOSS succeeds once again!!

I heard from Mr Marples that you are going to be co-authors of a scientific paper. This means that each of you will get a record of citations (by other scientists in their papers), which is in fact the distinguishing mark of a professional scientist....

This is a very difficult thing to achieve (normally restricted to people with PhDs!), because to get professionally published means essentially that, at least jointly, you have mastered a very very large body of knowledge and have done a colossal amount of work. It is not at all easy to become a published astronomer!!

Here is the B-band (photometric blue filter) image of NGC 5643, from the de Vaucouleurs atlas of galaxies : :

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The dust pattern within this galaxy is asymmetric and unusual, which could hypothetically be due to an interaction with a low mass companion galaxy.

There does exist a low contrast, fairly long, central bar structure in this galaxy, but it is more obvious in near-infrared imagery. The large-scale dust lanes seen within this bar seem to be rather weak, and not very symmetric. (this galaxy is usually classified as "weakly barred")

Here are the isophotes of the bar, as seen in the Ks band (near-infrared) from Mulchaey et al., 1997, ApJS, Vol.110, p.299 : :

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(1997 was when NIR observations were in their infancy; there are better images around these days at NIR wavelengths!)

An extant Analysis of some 2MASS near-infrared imaging data for this galaxy derived a bar Position Angle of 85 degrees, and a bar Ellipticity of 0.67
The figure of 0.67 indicates that this bar is relatively "fat" (oval in appearance)

The immediate region near to the centre of this galaxy is very intense (high surface brightness), in the optical regime. It is not possible to actually see much of an active (Seyfert) nucleus in this Hubble Space Telescope (WFPC2 instrument) image of the centralmost region of this galaxy [Visual (V-band)image in the left panel, and H-band (infrared) image in the central panel ] : : :

Click image for larger version

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However, the "starlike" nucleus is catalogued as a Type 2 Seyfert , and I seem to recall that there were some observations of a short outflow of gas from this nucleus, which was detected in both the [OIII] line and X-rays.
(It might just be possible to detect the Seyfert nucleus in very short exposures, or visually)
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