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Galaxies

Galaxies. 31 May 2014 Doug Horacek Resident Astronomer Von Braun Astronomical Society. Cosmic Lighthouses. Large Magellanic Cloud. Henrietta Leavitt & Harvard Computers. Published in 1908. Embarrassments!. Our galaxy seemed to be the largest.

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Galaxies

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  1. Galaxies 31 May 2014 Doug Horacek Resident Astronomer Von Braun Astronomical Society

  2. Cosmic Lighthouses Large Magellanic Cloud Henrietta Leavitt & Harvard Computers Published in 1908

  3. Embarrassments! • Our galaxy seemed to be the largest. • The globular clusters in M31 were underluminous by a factor of 4. • In 1952, Walter Baade discovered that there are two types of Cepheids and two period – luminosity relations. • Hubble based his distances on wrong type Cepheids and Andromeda was twice as far as he had calculated Population I Cepheids (Classical Cepheids) are relatively rich in heavy elements. Population II Cepheids (W Virginis stars) are relatively poor in heavy elements. Pop I Cepheids are four times more luminous than Pop II Cepheids.

  4. Distance Ladder Type 1 Supernovae RR Lyraes Distance in meters A number of RR Lyraes have been observed by the Hipparcos satellite which has determined accurate distances to them. When astronomers find RR Lyraes in the Large Magallenic Cloud, they can be used to calibrate the Period-Luminosity relation for Cepheids observed there. Similarly, when Type I supernovae in nearby galaxies with Cepheids in them (and thus known distances) were observed, the absolute magnitude of the supernova peak brightness was determined. Thus, a variety of distance determination techniques allow us to – one step at a time – learn the distances to ever more distant objects. Hipparcos – observed 100,000 stars 100 times over 4 years and > 1,000,000 others to less precision

  5. Edwin HubbleAmerican astronomer (1889-1953) Measured distances to nearby galaxies using Cepheid variables proving galaxies are islands of stars Discovered the Expansion of the Universe Developed a classification scheme for galaxies. Space telescope named after him!

  6. Hubble’s “Law” for Galaxies • Published in 1929 • Relates the recessional velocity (or redshift) to distance • Implies that the universe is expanding (from everywhere) • Astronomers have spent the last 7 decades trying to pin down accurate H0, primary difficulty establishing accurate distances over cosmologically significant scales • HST Key Science Project • Establish the Hubble Constant • Current value (2011): • H0 = 73.8 ± 2.4 (km/s)/Mpc The slope is the Hubble’s constant

  7. Accelerating Universe !! • The age of the universe with a Hubble’s constant of 70 km/sec/Mpc was uncomfortably close to the age of the oldest metal poor stars which are greater than 10 billion years old. • By 1998, supernova researchers using the HST knew something was afoot: the data showed the expansion of space was NOT slowing down but SPEEDING UP. • DARK ENERGY – Possible Solution • A vacuum is not perfectly empty. Quantum physics predicts that the vacuum is full of particles and anti-particles that pop into existence and a short time later, annihilate each other. • This dark energy exerts a repulsive force that causes the observed acceleration.

  8. Types of Galaxies • Spirals (Young) • Barred Spirals (Young) • Elliptical and Lenticular (Older) • Irregular Galaxies (Young to Middle Age) • Irregular Galaxies (Teenagers) • Seyfert Galaxies (Young) • Wolf-Rayet Galaxies (Middle Age) • Quasars

  9. Andromeda Galaxy 94mm Brandon and SBIG Camera Triangulum Galaxy 21 inch and SBIG Camera

  10. Messier 83 Barred Spiral in Hydra

  11. Elliptical M85 and Barred Spiral NGC 4393Part of Virgo Cluster

  12. Messier 82 Cigar GalaxyIn Ursa MajorTaken With Our Own Swanson 21 inch and Stella Cam II

  13. Hickson 31 Hickson 31 or Markarian 1089 or Arp 259 is one of the most luminous Wolf-Rayet galaxies known. The galaxy cluster is 166 million light years away and spans an area of 150 thousand light years.

  14. Compact Galaxy Clusters

  15. Hickson 31 Hickson 31 or Markarian 1089 or Arp 259 is one of the most luminous Wolf-Rayet galaxies known. The galaxy cluster is 166 million light years away and spans an area of 150 thousand light years.

  16. Copeland’s Septet( Hickson 57 or Arp 320) Copeland’s Septet near star 92 in Leo is a compact group of galaxies 480 million light years away that are interacting with each other. The largest and brightest galaxy of this group is NGC 3753 and is interacting with NGC 3754 just above it, and is a radio source. There are 11 total galaxies in this region, if your equipment picks up 17th magnitude PGC 36010 you are doing wonders with your telescope. The other dim PGC objects are on the outside of the field of view. The original Septet is NGC 3753, NGC 3754, NGC 3750, NGC 3751, NGC 3748, NGC 3745, and NGC 3746. The dimmer PGC 36010 shows up with the newer more sensitive instruments. PGC 169872 is shown in picture to the left taken with the VBAS 21 inch and Stella cam II Video Camera.

  17. Copeland’s SeptetTaken with VBAS 21 inchand Stella cam II Video Camera

  18. Large Scale Galaxy Clusters

  19. Distant Views

  20. Hubble Deep FieldMany Distant Galaxies in SameField of View

  21. Hubble Deep Field withGravitational LensingAround an old MassiveElliptical Galaxy

  22. Hubble works on the same principle as the first reflecting telescope built in the 1600s by Isaac Newton. Light enters the telescope and strikes a concave primary mirror, which acts like a lens to focus the light. The bigger the mirror, the better the image. In Hubble, light from the primary mirror is reflected to a smaller secondary mirror in front of the primary mirror, then back through a hole in the primary to instruments clustered behind the focal plane (where the image is in focus). Hubble Facts Angular resolution:Hubble's angular resolution is 0.05 arcsecond. This is the "sharpness" of Hubble's vision. If you could see as well as Hubble, you could stand in New York City and distinguish two fireflies, 1 m (3.3 feet) apart, in San Francisco. Mirror size: Primary mirror: 2.4 m (94.5 inches) in diameter Secondary mirror: 0.3 m (12 inches) in diameter

  23. Mission Goals: • Search for the first galaxies or luminous objects formed after the Big Bang. • Determine how galaxies evolved from their formation until now • Observe the formation of stars from the first stages to the formation of planetary systems • Measure the physical and chemical properties of planetary systems • and investigate the potential for life in those systems Sunshade manufacturing at NeXolve in Huntsville Mirror blank roughing at AxSys in Cullman Mirror testing at MSFC

  24. Celestial Awareness Poem Observing for Years To Most Distant Galaxies Look What We Have Found

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