This meeting is a tribute to Ken Freeman, his research and that with his students. Ken's most cited paper is undoubtedly "On the disks of spiral and S0 galaxies" (Freeman, 1970). Although it was de Vaucouleurs (e.g. 1959), who first showed observationally that the surface brightness distributions can be described by an exponential law, it was Ken in his seminal paper who collected the material available and studied the distribution of parameters and the dynamical relations. He derived the rotation curve and angular momentum distribution for an exponential disk in centrifugal equilibrium, found that 28 of the 36 galaxies have approximately the same face-on central surface brightness (known as "Freeman's law") and on the basis of the rotation curves of NGC300 and M33 concluded that there must be undetected matter of at least the mass of the detected galaxy.
Author(s) | Year | Reference | Subject | ADS citations | ||
Tot. | 9/0 | yr-1 | ||||
Schönberg & | 1942 | ApJ 96, 161 | H-burning and | 57 | 5 | 1.0 |
Chandrasekhar | S-C core | |||||
Baade | 1944 | ApJ 100, 137 | Stellar populations | 129 | 5 | 2.3 |
de Vaucouleurs | 1948 | An'Ap 11, 247 | R1/4-law | 388 | 42 | 7.5 |
Spitzer & | 1951 | ApJ 114, 385 | Secular evolution of | 111 | 5 | 2.3 |
Schwarzschild | stellar motions | |||||
Sandage & | 1952 | ApJ 116, 463 | Giant-branch evolu- | 55 | 6 | 1.1 |
Schwarzschild | tion; MS turn-off | |||||
Hoyle & | 1955 | ApJSuppl 2, 1 | Giant-branch evolu- | 87 | 5 | 1.9 |
Schwarzschild | tion; HR-diagrams | |||||
Salpeter | 1955 | ApJ 121, 161 | Salpeter-function | 922 | 154 | 20.5 |
Burbidges, | 1957 | RMP 29, 547 | Stellar nucleosyn- | 343 | 15 | 8.0 |
Fowler & Hoyle | thesis | |||||
Oort, Kerr & | 1958 | MN 118, 379 | HI structure of the | 40 | 2 | 2.0 |
Westerhout | Galaxy | |||||
Schmidt | 1959 | ApJ 129, 243 | SF; ``Schmidt-law'' | 376 | 39 | 9.2 |
King | 1962 | AJ 67, 471 | King law | 440 | 42 | 11.6 |
Sandage | 1962 | ApJ 135, 333 | NGC188 and chem- | 98 | - | 2.6 |
ical evolution | ||||||
Eggen, Lynden- | 1962 | ApJ 136, 748 | Collapse of the | 670 | 61 | 17.6 |
Bell & Sandage | Galaxy | |||||
Schmidt | 1963 | ApJ 137, 758 | G-dwarf problem | 227 | 10 | 6.1 |
Toomre | 1964 | ApJ 139, 1217 | Local disk stability | 607 | 83 | 16.9 |
Lin & Shu | 1964 | ApJ 140, 646 | Density wave theory | 232 | 18 | 6.4 |
Goldreich & | 1965 | MN 130, 97 | Disk instability and | 128 | 14 | 3.7 |
Lynden-Bell | 1965 | MN 130, 125 | spiral structure | 195 | 27 | 5.6 |
King | 1966 | AJ 71, 64 | King models | 803 | 46 | 23.6 |
Lynden-Bell | 1967 | MN 136, 101 | Violent relaxation | 347 | 25 | 10.5 |
Schmidt | 1968 | ApJ 151, 393 | Quasars;
V / V | 504 | 34 | 15.8 |
Tinsley | 1968 | ApJ 151, 547 | Photometric evolu- | 66 | 5 | 2.1 |
tion | ||||||
Freeman | 1970 | ApJ 160, 811 | Exponential disks | 820 | 84 | 27.3 |
Freeman, San- | 1970 | ApJ 160, 831 | Origin of Hubble | 232 | 11 | 7.7 |
dage & Stokes | types | |||||
Searle | 1971 | ApJ 168, 327 | Disk abundance | 349 | 10 | 12.0 |
gradients | ||||||
Peebles | 1971 | A&A 11, 377 | Origin of angular | 54 | 5 | 1.9 |
momentum | ||||||
Toomre & Toomre | 1972 | ApJ 178, 623 | Interacting galaxies | 785 | 90 | 28.0 |
Searle, Sargent & | 1973 | ApJ 179, 427 | Photometric evol- | 337 | 20 | 12.5 |
Bagnuolo | ution of galaxies | |||||
Ostriker & | 1973 | ApJ 186, 467 | Disk stability and | 439 | 29 | 16.3 |
Peebles | dark halos | |||||
Tully & Fisher | 1977 | A&A 54, 66 | TF-relation | 547 | 63 | 23.8 |
Wielen | 1977 | A&A 60, 263 | Secular evolution of | 220 | 29 | 9.6 |
stellar motions | ||||||
Larson & Tinsley | 1978 | ApJ 219, 46 | Photometric evolu- | 554 | 29 | 25.2 |
tion | ||||||
Searle & Zinn | 1978 | ApJ 225, 357 | Globular clusters | 539 | 58 | 24.5 |
and halo formation | ||||||
Tinsley | 1980 | FCP 5, 287 | Photometric and | 449 | 57 | 15.0 |
chemical evolution | ||||||
van der Kruit & | 1981 | A&A 95, 105 | 3-D galaxy disk | 280 | 20 | 14.8 |
Searle | model | |||||
Gilmore & Reid | 1983 | MN 202, 1025 | Galactic thick disk | 291 | 16 | 17.1 |
It is of some interest to see how Ken's 1970-paper compares in citation rate to others. For this purpose I collected such information using the NASA Astrophysics Data System (ADS). The citation scores in ADS are not complete, but certainly indicative and internally consistent. The first exercise was to draw up a list of what I feel are the most important papers related to studies of structure of galaxies. In Table 1 I give the total citation score up to the end of 2000, that for 1999+2000 ("9/0") and the average number of citations per year. In this listing I find only a few papers that are comparable or exceed Ken's 1970-paper in citations. These are Ed Salpeter's 1955 paper on star formation in the Galactic disk in which he defines the "Salpeter function", Ivan King's 1966 paper on the dynamics of globular clusters and the "King models" and the study by the Toomre & Toomre in 1973 on models for interacting galaxies.
To complete the search I also checked in ADS which papers between 1945 and 1975 were annually the most highly cited papers in Ap.J. (main journal), A.J., M.N.R.A.S. and A&A. One that comes close is the galaxy redshift survey of Humason et al. (1956) (754 citations, 16 in 1999+2000). Outside the field of galaxies there are two papers that clearly exceed it, namely Shakura & Sunyaev (1973; A&A 24, 337; 1823 citations and 313 in 1999+2000) on the appearance of black holes in binary systems and Nino Panagia (1973, AJ 78, 929; 1026 and 46) on parameters of early type stars, while Brocklehurst (1971, MN 153, 471; 787 and 28) on hydrogen population levels in gaseous nebulae comes close.
In any case, Ken's 1970 paper is well within the absolute top ten of citation scores of papers in astronomy and deservedly so.