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Arecibo as a redshift machine

Perseus-Pisces Supercluster. ~11,000 galaxy redshifts:. Arecibo as a redshift machine. [Giovanelli, Haynes et al. 1980s]. Perseus-Pisces Supercluster. Two Sloan Digital Sky Survey (SDSS) Wedges near The equator. 67676 galaxies Within 5deg og Equator [Tegmark et al 2003].

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Arecibo as a redshift machine

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  1. Perseus-Pisces Supercluster ~11,000 galaxy redshifts: Arecibo as a redshift machine [Giovanelli, Haynes et al. 1980s]

  2. Perseus-Pisces Supercluster

  3. Two Sloan Digital Sky Survey (SDSS) Wedges near The equator. 67676 galaxies Within 5deg og Equator [Tegmark et al 2003]

  4. Morphological Classification

  5. Elliptical vs Spiral Galaxies can be classified based on appearance

  6. Quantitative Morphology Photometric surface brightness profile “de Vaucouleurs’ profile”: I(r)= I(re) exp[-(r/re)¼] where re is the “effective radius” and L(<re)=½ Ltotal Works for ellipticals and for bulges “exponential profile”: I(r)= I(0) exp[-r/rd] where rd is the “exponential scale length”. Works for spiral disks

  7. Integrated Galaxy Spectra MgI MgI H H Ellipticals show absorption line spectra characteristic of older stellar population; spirals show emission lines, characteristic of star-formation regions.

  8. Galaxy Exotica

  9. The Antennae

  10. Toomre & Toomre 1972 Restricted 3-body problem

  11. NGC 3628 Leo Triplet Haynes, Giovanelli & Roberts 1979 Arecibo data NGC 3627 NGC 3623

  12. Morphological Distortions Resulting from Gravitational Interaction: Example # 1

  13. A Computer Simulation of the Merger of two Spiral galaxies

  14. Morphology-Density Relation Ellipticals The fraction of the population that is spiral decreases from the field to high density regions. Spirals/Irr S0 Low r High r [Dressler 1980]

  15. Virgo Cluster HI Deficiency HI Disk Diameter Arecibo data [Giovanelli & Haynes 1983]

  16. Morphological Alteration Mechanisms • I. Environment-independent • Galactic winds • Star formation without replenishment • II. Environment dependent • a. Galaxy-galaxy interactions • Direct collisions • Tidal encounters • Mergers • b. Galaxy-cluster medium • i. Ram pressure stripping • ii. Thermal evaporation • iii. Turbulent viscous stripping

  17. Disk Formation: a primer • Protogalaxies acquire angular momentum through tidal torques with nearest neighbors during the linear regime [Stromberg 1934; Hoyle 1949] • As self-gravity decouples the protogalaxy from the Hubble flow, [l/(d l/d t)] becomes v.large and the growth of l ceases • N-body simulations show that at turnaround time values of l range between 0.01 and 0.1, for halos of all masses • The average for halos isl = 0.05 • Only 10% of halos havel < 0.025 or l > 0.10 • halos achieve very • modest rotational support The spin parameter l quantifies the degree of rotational support of a system : For E galaxies, l ~ 0.05 For S galaxies, l ~ 0.5 • Baryons collapse dissipatively within the potential well of their halo. They lose energy through radiative losses, largely conserving mass and angular momentum • Thus l of disks increases, as they shrink to the inner part of the halo. • [Fall & Efstathiou 1980] Angular momentum Mass Total Energy • If the galaxy retains all baryons  m_d~1/10 , and l_disk grows to ~ 0.5, • R_disk ~ 1/10 R_h (mass of disk) /(total mass)

  18. Some galaxies form through multiple (and often major) mergers The orbits of their constituent stars are randomly oriented Kinetic energy of random motions largely exceeds that of orderly, large- scale motions such as rotation. These galaxies have low “spin parameter” Elliptical galaxies

  19. Other galaxies form in less crowded environments They accrete material at a slower pace and are unaffected by major mergers for long intervals of time Baryonic matter (“gas”) collapses slowly (and dissipatively – losing energy) within the potential well of Dark matter, forming a disk Baryonic matter has high spin parameter: large-scale rotation is important Spiral Galaxy

  20. Scaling Laws for Disks * For a disk mass fraction * If the disk mass assumes an exponential distribution * and if the disk angular momentum fraction is then [see Mo et al 1998; ; Dalcanton et al. 1997; Firmani & Avila-Reese 2000]

  21. Scaling Laws for Disks When a more realistic density profile is adopted (e.g. NFW), the scaling relations of disks become: Where are dimensionless parameters of order 1, that take into account respectively the degree of concentration of the halo, the shape of the rotation curve and the radius at which it is measured.

  22. Scale-length—Velocity Width • SFI and SFI+samples: • I band CCD photometry • Sbc-Sc spirals • cz < 10000 km/s • HI and Ha spectroscopy • SFI: Giovanelli, Haynes, da Costa, • Freudling, Salzer, Wegner • 1600 galaxies • SFI++: Haynes & Giovanelli • 4500 galaxies

  23. Central Disk Surface Brightness—Velocity Width Expected slope from Scaling law “Visibility” function

  24. TF Relation: Data “Direct” slope is –7.6 “Inverse” slope is –7.8 SCI : cluster Sc sample …which is similar to the explicit theory-derived dependencea = 3 I band, 24 clusters, 782 galaxies [Giovanelli et al. 1997] a [WhereL a (rot. vel.) ]

  25. The MW galaxy

  26. The Milky Way as a naked eye object

  27. The Near Infrared Sky

  28. Multiwavelength Milky Way 408 MHz 2.7GHz HI (21 cm) CO FIR (IRAS) MIR (6-10m) NIR (1.2-3.5 m) Optical X-ray(0.25-1.5KeV) Gamma (300 MeV)

  29. Galactic Components

  30. Spiral Structure in the Milky Way The Sun is located on the inner side of a spiral arm, at the periphery of the Galaxy Spiral arms are traced by “young” objects: recently formed stars, gas and dust Spiral structure is a wave-like phenomenon: the wave travels through the material contents of the galaxy, as a wave travels across the surface of the ocean.

  31. Motions Spheroidal components (bulge, halo): random motions around the Galactic Center • Disk rotates differentially • circular motion in the • disk • V(R) ~ 220 km/s

  32. Milky Way Rotation Curve  Dark Matter is needed to explain the Milky Way dynamics  The fractional contribution of the Dark Matter to the total mass contained within a given radius increases outwards The total mass of the Galaxy is dominated by Dark Matter

  33. The Local Group of Galaxies • Includes ~35 galaxies • MW & M31 are dominant • Mostly dwarfs which cluster around giants http://www.anzwers.org/free/universe/virgo.html

  34. LMC SMC The Magellanic Clouds • The Magellanic Clouds are contained within a common HI envelope. • The Magellanic Stream traces their interaction with the MW.

  35. Giant spiralsdSph (+dEll)dIrr dIrr/dSph Substructure in the Local Group Diagram from Sarah Maddison

  36. High Velocity Clouds ? Credit: B. Wakker

  37. The Magellanic Stream Discovered in 1974 by Mathewson, Cleary & Murray Putman et al. 2003

  38. The Galactic Center

  39. The Center of the Milky Way

  40. The Inner Half kpc (4x3 deg) of the MW at l = 90 cm (330 MHz)

  41. The Galactic Center: Radio Filaments Filaments  disk are produced by nonthermal emission. Structure is regulated by ordered magnetic fields Core is thermal, fed by young stars. 20 cm map of inner 30 pc

  42. Infrared Observations At optical wavelengths, the view is obscured. • At 2.2 m: direct stellar emission from cooler stars (types K & M) that coexist in clusters with the hotter ones that heat the HII regions. • At 10 m: emission from dust which is heated by higher energy (optical) photons emitted by stars and then re-emits in the IR. • At 100 m, emission due to cooler dust, more extended, heated by energetic photons from hot stars over 10’s of parsecs distant.

  43. Galactic Center: NIR image The stellar density in the Galactic Center is 300,000 X that of the solar neighborhood. http://www.gemini.edu/gallery/observing/density.html

  44. The Galactic Center: NIR mosaic • Mosaic of J,H,K • (1.2 to 3.5 ) images of the GC region. • blue= “hot” • red= “cool” The two yellow arrows mark the position of SgrA*

  45. Young stellar clusters in the GC Young, massive, high density • The young stellar clusters in the GC are truly remarkable for their population of high mass stars • Central cluster: located within the central pc. Contains over 30 massive stars; age ~ 3 to 5 Myr; • Moves with SgrA* to within 70 km/s • Arches cluster: within 30 pc, contains > 150 O stars within 0.6 pc radius; very high density; • Age ~2.5 ±0.5 Myr (younger). • Quintuplet cluster: also within 30 pc of center. • > 30 massive stars; age ~ 3 to 5 Myr.

  46. Extreme Environment • High density ~ 3 x 105 M pc-3 • Strong tidal forces • Clusters disrupted in < 10 to 50 Myr

  47. The Galactic Center: Radio Filaments Filaments  disk are produced by nonthermal emission. Structure is regulated by ordered magnetic fields Core is thermal, fed by young stars. 20 cm map of inner 30 pc

  48. The Sgr A Complex • Schematic diagram of the main components of the SgrA radio complex. • Note the radio mini-spiral. • The SMBH candidate SgrA* is located at the center of the cavity within the molecular disk. The ionized gas and hot massive stars also lie within this disk. • SgrA West = HII region • SgrA East = SNR? Baganoff et al 2003 ApJ 591, 91

  49. Radio continuum “Mini-spiral” Core source: inner 3 pc Sgr A Thermal emission from young stars Sgr A*: compact nonthermal radio source Unusual time-variable 511 keV e- - e+ annihilation radiation

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