madbadgalaxyman
21-06-2014, 10:26 AM
Here is an excellent and concise and understandable set of lecture notes, quite descriptive, with only a few equations, about those gigantic spheroidal structures made of stars that we call Bulges , together with a comparison of Bulges with Elliptical Galaxies ::
http://arxiv.org/abs/1208.2295
This set of notes is by Dimitri Gadotti, a good and solid and practical Observational Extragalactic Astronomer who focusses on measuring the physical properties of galaxies, in the practical sense of assigning and measuring numerical parameters to various galaxies.
Wisely, in these notes, Gadotti prefers to use graphs to display the relations between various numerical parameters, which makes this lecture much easier to understand for the "less mathematical brethren"
_____________________________
WANT EVEN MORE DETAIL?!?! ...........@#@^%&^*^$#!!!??
The following review paper by Alister Graham is rather like an expanded version of Gadotti's lecture notes:
http://astronomy.swin.edu.au/~agraham/Preprints/Springer.html
This Long review paper has encyclopaedic coverage of how the structure of Galaxy Bulges and Elliptical Galaxies is measured and described and classified by today's astronomers.
The classification & description of Elliptical Galaxies and of Galaxy Bulges by today's astronomers, has little to do with the venerable Hubble galaxy classification system, as it is all about measuring and graphing numerical parameters such as: surface brightness, galaxy shape, color index, rotational velocity, stellar orbits, etc. In fact, work on a proper understanding and description and classification of these "big spheroidal structures" had to wait until the mid-1980s when CCDs became available ;
photographic photometry of galaxies had been possible, but it was difficult and slow, and it was often inaccurate!
This review is by Alister Graham, who - in my humble opinion - ranks as one of the top 5 quantitative galaxy morphologists and classifers, very much the heir of the formidable John Kormendy. We are lucky to have Graham in Australia, at Swinburne University.
The lore and mindset and classification terminology of those people who classify and describe the morphology of bulges, spheroids and Elliptical Galaxies is very different (and less accessible to those amateurs who like things at the descriptive level) to the traditional Hubble-style Galaxy Classification efforts of people such as Ron Buta and Harold Corwin and Alan Sandage....... who primarily classify and describe the morphology of the disk components within galaxies.
Graham is a brilliant example of someone who classifies and describes spheroidal stellar structures, and this sort of work is not really burdened by the historical baggage of the venerable Hubble classification system.
http://arxiv.org/abs/1208.2295
This set of notes is by Dimitri Gadotti, a good and solid and practical Observational Extragalactic Astronomer who focusses on measuring the physical properties of galaxies, in the practical sense of assigning and measuring numerical parameters to various galaxies.
Wisely, in these notes, Gadotti prefers to use graphs to display the relations between various numerical parameters, which makes this lecture much easier to understand for the "less mathematical brethren"
_____________________________
WANT EVEN MORE DETAIL?!?! ...........@#@^%&^*^$#!!!??
The following review paper by Alister Graham is rather like an expanded version of Gadotti's lecture notes:
http://astronomy.swin.edu.au/~agraham/Preprints/Springer.html
This Long review paper has encyclopaedic coverage of how the structure of Galaxy Bulges and Elliptical Galaxies is measured and described and classified by today's astronomers.
The classification & description of Elliptical Galaxies and of Galaxy Bulges by today's astronomers, has little to do with the venerable Hubble galaxy classification system, as it is all about measuring and graphing numerical parameters such as: surface brightness, galaxy shape, color index, rotational velocity, stellar orbits, etc. In fact, work on a proper understanding and description and classification of these "big spheroidal structures" had to wait until the mid-1980s when CCDs became available ;
photographic photometry of galaxies had been possible, but it was difficult and slow, and it was often inaccurate!
This review is by Alister Graham, who - in my humble opinion - ranks as one of the top 5 quantitative galaxy morphologists and classifers, very much the heir of the formidable John Kormendy. We are lucky to have Graham in Australia, at Swinburne University.
The lore and mindset and classification terminology of those people who classify and describe the morphology of bulges, spheroids and Elliptical Galaxies is very different (and less accessible to those amateurs who like things at the descriptive level) to the traditional Hubble-style Galaxy Classification efforts of people such as Ron Buta and Harold Corwin and Alan Sandage....... who primarily classify and describe the morphology of the disk components within galaxies.
Graham is a brilliant example of someone who classifies and describes spheroidal stellar structures, and this sort of work is not really burdened by the historical baggage of the venerable Hubble classification system.