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Types of galaxies

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Mae Monteveros

Types of galaxies You can edit this powerpoint for your own presentation but don't re-upload. I used hyperlink(especially on images) and alot of animation.

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TYPES GALAXIES OF By: Mae Ann M. Crisponde
Spiral GalaxiesElliptical Galaxies Irregular Galaxies
• shaped like a spheroid/elongated sphere. • smooth, with the surface brightness decreasing as you go farther out from the center. • no particular axis of rotation. • They don’t have spiral structure.
(a) they have much more random star motion than orderly rotational motion (b) they have very little dust and gas left between the stars; (c) this means that they have no new star formation occurring now and no hot, bright, massive stars in them (those stars are too short- lived); and (d) they have no spiral structure. four distinguishing characteristics
Types of galaxies
Spiral Galaxies • no regular/symmetrical structure• are flat with a spiral pattern in their disk• containing stars, gas and dust, and a central concentration of stars known as the bulge. • Our own Milky Way has recently (in the 1990s) been confirmed to be a barred spiral
a spherical structure found in the center of the galaxy. This feature mostly contains older stars. The disk is made up of dust, gas, and younger stars. The disk forms arm structures. Our Sun is located in an arm of our galaxy, the Milky Way. The halo of a galaxy is a loose, spherical structure located around the bulge and some of the disk. The halo contains old clusters of stars, known as globular clusters.
• Designated by S or SA • Designated by SB • In normal spirals the arms originate directly from the nucleus, or bulge, where in the barred spirals there is a bar of material that runs through the nucleus that the arms emerge from. Both of these types are given a classification according to how tightly their arms are wound. The classifications are a, b, c, d ... with "a" having the tightest arms. In type "a", the arms are usually not well defined and form almost a circular pattern.
Two groups have HII regions, which are regions of elemental hydrogen gas, and many Population I stars, which are young hot stars. simply seem to have large amounts of dust that block most of the light from the stars. All this dust makes is almost impossible to see distinct stars in the galaxy. Irr I Irr II Irregular Galaxies
ACCORDING TO:
The Andromeda galaxy is the closest galaxy to our own, the Milky Way. It is also a similar shape to the Milky Way, although it is four times bigger! It can be visible from Earth on a clear night provided there are no lights nearby illuminating the sky and the Moon is a New Moon and therefore not visible. THE ANDROMEDA GALAXY
TWO GALAXIES COLLIDING
A PINWHEEL GALAXY
SOMBRERO GALAXY This galaxy is known as the Sombrero Galaxy because it resembles a Mexican hat. It has a large Galactic Centre and the stars in it appear to spin around it more like the rings of Saturn than the stars in a Spiral Galaxy.
Elliptical Galaxies
Spiral galaxy M100
Irregular Galaxies
Types of galaxies
ALL RIGHTS RESERVED Resources used: Elliptical Galaxy - https://en.wikipedia.org/wiki/Elliptical_galaxy Spiral Galaxy - https://en.wikipedia.org/wiki/Spiral_galaxy Irregular Galaxy - https://en.wikipedia.org/wiki/Irregular_galaxy Types of galaxies -->http://www.astro.cornell.edu/academics/courses/astro201/galaxies/types.htm -->http://space-facts.com/galaxy-types/ -->http://classroom.synonym.com/three-main-types-galaxies-2474.html Graphics used: www.yandex.ru
Components GALAXIES of our By: Ma. Chrissa Abada
Components of our Galaxy Disk Young/blue stars some in open clusters, heavy elements Bulge old/yellow stars globular clusters, hot gas, few heavy elements Visible halo Dark halo dark matter --- made of ??? 90% of mass of galaxy Galactic center opaque in optical - see in IR, radio, X-rays, Black Hole - 2.6 million solar masses
© 2004 Pearson Education Inc., publishing as Addison-Wesley • Disk • younger generation of stars • contains gas and dust • location of the open clusters • Bulge • mixture of both young and old stars • Halo • older generation of stars • contains no gas or dust • location of the globular clusters
© 2004 Pearson Education Inc., publishing as Addison-Wesley • How do halo stars differ from disk stars? • What does the environment around hot stars look like?
© 2004 Pearson Education Inc., publishing as Addison-Wesley • Stars in the disk are relatively young. • plenty of high- and low-mass stars, blue and red • Stars in the halo are old. • mostly low-mass, red stars • Stars in the halo must have formed early in the Milky Way Galaxy’s history. • star formation stopped long ago in the halo when all the gas flattened into the disk
© 2004 Pearson Education Inc., publishing as Addison-Wesley • O & B stars (T > 25,000K) make enough UV photons to ionize hydrogen in the nebula
© 2004 Pearson Education Inc., publishing as Addison-Wesley • Light from central star is reflected and scattered by dust • Similar to our blue sky lit up by a yellow Sun
© 2004 Pearson Education Inc., publishing as Addison-Wesley Radio X-ray Although dark in visual light, there are bright radio, IR, and X-ray sources at the center of the Galaxy, known as Sgr A*.
© 2004 Pearson Education Inc., publishing as Addison-Wesley • The rapid flare rise/drop time (< 10 min) implied that the emission region is only 20 times the size of the event horizon of the 2.6 million M black hole. • Energy from flare probably came from a comet-sized lump of matter…torn apart before falling beneath the event horizon! Chandra image of Sgr A*
In 1924, Edwin Hubble divided galaxies into different “classes” based on their appearance.
•Disk + spiral arms + bulge (usually) •Subtype a b c defined by 3 criteria: •Bulge/disk luminosity ratio •Sa: B/D>1 Sc: B/D<0.2 •Spiral pitch angle •Sa: tightly wound arms Sc: loosely wound arms •Degree of resolution into knots, HII regions, etc.
•Contain a linear feature of nearly uniform brightness centered on nucleus •Subclasses follow those of spirals with subtypes a b and c
•Smooth structure and symmetric, elliptical contours •Subtype E0 - E7 defined by flattening
•Smooth, central brightness concentration (bulge similar to E) surrounded by a large region of less steeply declining brightness (similar to a disk) •No spiral arm structure
•No morphological symmetry •Lots of young, blue stars and interstellar material •Smaller than most spirals and elliptical galaxies •Two major subtypes: •Irr I: spiral-like but without defined arms, show bright knots with O,B stars •Irr II: asymmetrical with dust lanes and gas filaments (e.g. M82) - explosive M82-Irr IINGC 4485-Irr II Irr I
No Bar Bar Spiral shaped Ring shaped Cross section of diagram E E+ S0- S0 S0+ Sa Sb Sc Sd Sm Im Limitations: •E  Im is not a linear sequence of one parameter •Rings and bars are not independent •Does not take into consideration mass or other important parameters. All based on optical surface brightness morphology.
A couple of galaxy classes not addressed in these systems…. Leo I dSph Dwarf Spheroidals – dSph •overall low star density •appear as a cluster of faint stars. The Sculptor system (Shapley 1938) was the first to be discovered. dSph are the low-luminosity counterparts of dEs. Dwarf Ellipticals – dE •much less luminous than the normal elliptical galaxy. •Typically a few kpc across and contain 1 million stars. NGC 205
ALL RIGHTS RESERVED Resources used: file:///C:/Users/nanami/Documents/origin%20of%20the%20galaxy/origin%20of%20structure.html file:///C:/Users/nanami/Documents/origin%20of%20the%20galaxy/Galaxies.html file:///C:/Users/nanami/Documents/Websites/Astronomy%20-%20Galaxies/Origin%20of%20Galaxies.html file:///C:/Users/nanami/Documents/Websites/Astronomy%20- %20Galaxies/Galaxy%20morphological%20classification%20-%20Wikipedia,%20the%20free%20encyclopedia.html Graphics used: www.yandex.ru
ORIGIN GALAXIES OF By: Baby Gay Mirando
• The galaxies are the building blocks of the Universe. Each of them comprises some hundred billion radiant stars, such as our sun, which extend across about 50,000 light years. • . Every galaxy is embedded in a spherical halo made of dark matter that cannot be seen but is detected through its massive gravitational attraction. • All galaxies began forming at about the same time approximately 13 billion years ago.
Types of galaxies
Types of galaxies
top – down proposes that galaxies formed from huge gas clouds that collapsed by gravity. The rate of rotation of the cloud determined the type of galaxy; slow rotation producing elliptical galaxies, faster rotation producing spiral or lenticular galaxies. Very large clouds could fragment to produce multiple clouds, each producing a galaxy. This would explain the clustering and superclustering of galaxies.
Types of galaxies
bottom-up • this theory argues that small gas clouds merged due gravity and then condensed to form the galaxies, instead of one gas cloud breaking apart and forming many galaxies. • In this theory, the galaxies started out small, probably around the size of the Magellanic Clouds and other irregular galaxies observable today. • In fact, the Milky Way is predicted to collide with the Andromeda Galaxy in four billion years.
Types of galaxies
 The "bottom-up" model builds galaxies from the merging of smaller clumps about the size of a million solar masses (the sizes of the globular clusters). These clumps would have been able to start collapsing when the universe was still very young. Then galaxies would be drawn into clusters and clusters into superclusters by their mutual gravity.  The dwarf irregular galaxies may be from cloud fragments that did not get incorporated into larger galaxies.
Types of galaxies
Both the top-down model and the bottom-up model have been promoted time and time again as the leading theories of galaxy formation. These theories share similarities, but they differ on some critical points: 1. Whether the galaxies formed from a few large gas clouds or from many small gas clouds and 2. Whether the merging of galaxies was a major factor in early galaxy formation.
• The radio galaxy MRC 1138-262, also called the "Spiderweb Galaxy" is a large galaxy in the making.
ALL RIGHTS RESERVED Resources used: file:///C:/Users/nanami/Documents/Websites/Astronomy%20- %20Galaxies/Galaxies%20and%20the%20Universe%20-%20Stellar%20Content%20of%20Galaxies.html file:///C:/Users/nanami/Documents/Websites/Galaxies/Components%20of%20the%20Galaxy.html Graphics used: www.yandex.ru

More Related Content

Types of galaxies

  • 3. • shaped like a spheroid/elongated sphere. • smooth, with the surface brightness decreasing as you go farther out from the center. • no particular axis of rotation. • They don’t have spiral structure.
  • 4. (a) they have much more random star motion than orderly rotational motion (b) they have very little dust and gas left between the stars; (c) this means that they have no new star formation occurring now and no hot, bright, massive stars in them (those stars are too short- lived); and (d) they have no spiral structure. four distinguishing characteristics
  • 6. Spiral Galaxies • no regular/symmetrical structure• are flat with a spiral pattern in their disk• containing stars, gas and dust, and a central concentration of stars known as the bulge. • Our own Milky Way has recently (in the 1990s) been confirmed to be a barred spiral
  • 7. a spherical structure found in the center of the galaxy. This feature mostly contains older stars. The disk is made up of dust, gas, and younger stars. The disk forms arm structures. Our Sun is located in an arm of our galaxy, the Milky Way. The halo of a galaxy is a loose, spherical structure located around the bulge and some of the disk. The halo contains old clusters of stars, known as globular clusters.
  • 8. • Designated by S or SA • Designated by SB • In normal spirals the arms originate directly from the nucleus, or bulge, where in the barred spirals there is a bar of material that runs through the nucleus that the arms emerge from. Both of these types are given a classification according to how tightly their arms are wound. The classifications are a, b, c, d ... with "a" having the tightest arms. In type "a", the arms are usually not well defined and form almost a circular pattern.
  • 9. Two groups have HII regions, which are regions of elemental hydrogen gas, and many Population I stars, which are young hot stars. simply seem to have large amounts of dust that block most of the light from the stars. All this dust makes is almost impossible to see distinct stars in the galaxy. Irr I Irr II Irregular Galaxies
  • 11. The Andromeda galaxy is the closest galaxy to our own, the Milky Way. It is also a similar shape to the Milky Way, although it is four times bigger! It can be visible from Earth on a clear night provided there are no lights nearby illuminating the sky and the Moon is a New Moon and therefore not visible. THE ANDROMEDA GALAXY
  • 14. SOMBRERO GALAXY This galaxy is known as the Sombrero Galaxy because it resembles a Mexican hat. It has a large Galactic Centre and the stars in it appear to spin around it more like the rings of Saturn than the stars in a Spiral Galaxy.
  • 19. ALL RIGHTS RESERVED Resources used: Elliptical Galaxy - https://en.wikipedia.org/wiki/Elliptical_galaxy Spiral Galaxy - https://en.wikipedia.org/wiki/Spiral_galaxy Irregular Galaxy - https://en.wikipedia.org/wiki/Irregular_galaxy Types of galaxies -->http://www.astro.cornell.edu/academics/courses/astro201/galaxies/types.htm -->http://space-facts.com/galaxy-types/ -->http://classroom.synonym.com/three-main-types-galaxies-2474.html Graphics used: www.yandex.ru
  • 21. Components of our Galaxy Disk Young/blue stars some in open clusters, heavy elements Bulge old/yellow stars globular clusters, hot gas, few heavy elements Visible halo Dark halo dark matter --- made of ??? 90% of mass of galaxy Galactic center opaque in optical - see in IR, radio, X-rays, Black Hole - 2.6 million solar masses
  • 22. © 2004 Pearson Education Inc., publishing as Addison-Wesley • Disk • younger generation of stars • contains gas and dust • location of the open clusters • Bulge • mixture of both young and old stars • Halo • older generation of stars • contains no gas or dust • location of the globular clusters
  • 23. © 2004 Pearson Education Inc., publishing as Addison-Wesley • How do halo stars differ from disk stars? • What does the environment around hot stars look like?
  • 24. © 2004 Pearson Education Inc., publishing as Addison-Wesley • Stars in the disk are relatively young. • plenty of high- and low-mass stars, blue and red • Stars in the halo are old. • mostly low-mass, red stars • Stars in the halo must have formed early in the Milky Way Galaxy’s history. • star formation stopped long ago in the halo when all the gas flattened into the disk
  • 25. © 2004 Pearson Education Inc., publishing as Addison-Wesley • O & B stars (T > 25,000K) make enough UV photons to ionize hydrogen in the nebula
  • 26. © 2004 Pearson Education Inc., publishing as Addison-Wesley • Light from central star is reflected and scattered by dust • Similar to our blue sky lit up by a yellow Sun
  • 27. © 2004 Pearson Education Inc., publishing as Addison-Wesley Radio X-ray Although dark in visual light, there are bright radio, IR, and X-ray sources at the center of the Galaxy, known as Sgr A*.
  • 28. © 2004 Pearson Education Inc., publishing as Addison-Wesley • The rapid flare rise/drop time (< 10 min) implied that the emission region is only 20 times the size of the event horizon of the 2.6 million M black hole. • Energy from flare probably came from a comet-sized lump of matter…torn apart before falling beneath the event horizon! Chandra image of Sgr A*
  • 29. In 1924, Edwin Hubble divided galaxies into different “classes” based on their appearance.
  • 30. •Disk + spiral arms + bulge (usually) •Subtype a b c defined by 3 criteria: •Bulge/disk luminosity ratio •Sa: B/D>1 Sc: B/D<0.2 •Spiral pitch angle •Sa: tightly wound arms Sc: loosely wound arms •Degree of resolution into knots, HII regions, etc.
  • 31. •Contain a linear feature of nearly uniform brightness centered on nucleus •Subclasses follow those of spirals with subtypes a b and c
  • 32. •Smooth structure and symmetric, elliptical contours •Subtype E0 - E7 defined by flattening
  • 33. •Smooth, central brightness concentration (bulge similar to E) surrounded by a large region of less steeply declining brightness (similar to a disk) •No spiral arm structure
  • 34. •No morphological symmetry •Lots of young, blue stars and interstellar material •Smaller than most spirals and elliptical galaxies •Two major subtypes: •Irr I: spiral-like but without defined arms, show bright knots with O,B stars •Irr II: asymmetrical with dust lanes and gas filaments (e.g. M82) - explosive M82-Irr IINGC 4485-Irr II Irr I
  • 35. No Bar Bar Spiral shaped Ring shaped Cross section of diagram E E+ S0- S0 S0+ Sa Sb Sc Sd Sm Im Limitations: •E  Im is not a linear sequence of one parameter •Rings and bars are not independent •Does not take into consideration mass or other important parameters. All based on optical surface brightness morphology.
  • 36. A couple of galaxy classes not addressed in these systems…. Leo I dSph Dwarf Spheroidals – dSph •overall low star density •appear as a cluster of faint stars. The Sculptor system (Shapley 1938) was the first to be discovered. dSph are the low-luminosity counterparts of dEs. Dwarf Ellipticals – dE •much less luminous than the normal elliptical galaxy. •Typically a few kpc across and contain 1 million stars. NGC 205
  • 37. ALL RIGHTS RESERVED Resources used: file:///C:/Users/nanami/Documents/origin%20of%20the%20galaxy/origin%20of%20structure.html file:///C:/Users/nanami/Documents/origin%20of%20the%20galaxy/Galaxies.html file:///C:/Users/nanami/Documents/Websites/Astronomy%20-%20Galaxies/Origin%20of%20Galaxies.html file:///C:/Users/nanami/Documents/Websites/Astronomy%20- %20Galaxies/Galaxy%20morphological%20classification%20-%20Wikipedia,%20the%20free%20encyclopedia.html Graphics used: www.yandex.ru
  • 39. • The galaxies are the building blocks of the Universe. Each of them comprises some hundred billion radiant stars, such as our sun, which extend across about 50,000 light years. • . Every galaxy is embedded in a spherical halo made of dark matter that cannot be seen but is detected through its massive gravitational attraction. • All galaxies began forming at about the same time approximately 13 billion years ago.
  • 42. top – down proposes that galaxies formed from huge gas clouds that collapsed by gravity. The rate of rotation of the cloud determined the type of galaxy; slow rotation producing elliptical galaxies, faster rotation producing spiral or lenticular galaxies. Very large clouds could fragment to produce multiple clouds, each producing a galaxy. This would explain the clustering and superclustering of galaxies.
  • 44. bottom-up • this theory argues that small gas clouds merged due gravity and then condensed to form the galaxies, instead of one gas cloud breaking apart and forming many galaxies. • In this theory, the galaxies started out small, probably around the size of the Magellanic Clouds and other irregular galaxies observable today. • In fact, the Milky Way is predicted to collide with the Andromeda Galaxy in four billion years.
  • 46.  The "bottom-up" model builds galaxies from the merging of smaller clumps about the size of a million solar masses (the sizes of the globular clusters). These clumps would have been able to start collapsing when the universe was still very young. Then galaxies would be drawn into clusters and clusters into superclusters by their mutual gravity.  The dwarf irregular galaxies may be from cloud fragments that did not get incorporated into larger galaxies.
  • 48. Both the top-down model and the bottom-up model have been promoted time and time again as the leading theories of galaxy formation. These theories share similarities, but they differ on some critical points: 1. Whether the galaxies formed from a few large gas clouds or from many small gas clouds and 2. Whether the merging of galaxies was a major factor in early galaxy formation.
  • 49. • The radio galaxy MRC 1138-262, also called the "Spiderweb Galaxy" is a large galaxy in the making.
  • 50. ALL RIGHTS RESERVED Resources used: file:///C:/Users/nanami/Documents/Websites/Astronomy%20- %20Galaxies/Galaxies%20and%20the%20Universe%20-%20Stellar%20Content%20of%20Galaxies.html file:///C:/Users/nanami/Documents/Websites/Galaxies/Components%20of%20the%20Galaxy.html Graphics used: www.yandex.ru