1	Astr 5460 Wed. Sep. 8, 2004 Today: Classification and Morphology Kinematics and Masses (Skipping Ch. 2 of Combes et al. on ISM. If you didn’t take ISM last spring, you should read it.) Unless noted, all figs and equations from Combes et al. or Longair’s Galaxy Formation. Homework questions/discussion WIRO discussion
2	Luminosity Functions
3	Luminosity Functions Features to note Morphology matters, also field vs. cluster. L* or M* in rich clusters isn’t a bad “standard candle” cD galaxies in cluster centers are special cases; they are like massive ellipticals but have extra stellar envelopes. They do not fit extrapolations of ellipitical LFs. Low luminosity end of LFs not well determined (Irr and dwarf ellipticals). Again SDSS will probably be the best word on this (if it goes faint enough).
4	Frequency of Galaxy Types
5	Frequency of Galaxy Types
6	Frequency of Galaxy Types: As a function of clustering
7	Trends along Hubble Sequence
8	Trends along Hubble Sequence Roberts & Haynes 1994:
9	Trends along Hubble Sequence Roberts & Haynes 1994: Masses from S0 to Scd roughly constant, then decrease, and M/L roughly the same – more next chapter (3) H I not significant in ellipticals (< 1 in 10000), but is in spirals (0.01 to 0.15 from Sa to Sm) (see Ch. 2) Total surface density decreases, H I surface density increases Ellipticals are red, spirals are blue… H II regions frequency increases monotonically along the sequence (Kennicutt et al. 1989) Star formation rates appear key to these relations
10	Cosmic Star Formation History From Hopkins et al. (2001)
11	Kinematics and Masses of Galaxies (Ch. 3, Combes et. al) Optical Determinations Methods – optical rotation curves Properties of rotation curves Radio Determinations – HI maps Mass Distributions Methods of Analysis M/L Ratios Tully-Fischer Law
12	Kinematics and Masses of Galaxies Taken both from Combes et al. and Longair, as needed. How do we measure the masses of astronomical objects, in general? Of binary stars? Of single stars? Of groups of many objects, like galaxies?
13	Galaxy Masses Rotation Curves of Spiral Galaxies: This just comes from Newton, by equating gravity to centripetal acceleration. This produces Kepler’s third law, and “Keplerian” orbital velocities around point sources fall off as r^-1/2. How about for galaxies?
14	The Galactic Rotation Curve Keplerian fall-off near center indicates compact mass at center Flat curve throughout disk indicates much distributed mass Lack of fall-off beyond visible “edge” indicates “dark matter”
15	Galaxy Rotation Curves
16	Galaxy Rotation Curves
17	Normalized mass distributions based on average rotation curves for different “types.” Sc is type I, Sa and Sb are of all three types. The famous Tully-Fisher law (basically L ~ V4). Mike Pierce is an expert. Why is H-band better and why is this so important in extragalactic astronomy? What is its origin?