The Andromeda Galaxy pp 321-339 | Cite as

# Annotated Bibliography, 1885–1950

## Abstract

References to papers dealing with M31 are listed here in order of the year of appearance. Brief annotations are given for most of them. The first part of this compilation is based in part on work done many years ago by students at the University of California, Berkeley, as a class project. Especially hard-working were Conrad Sturch, Ralph Robbins, K. S. Krishna Swamy, Carol Webb, and Ann Merchant (Boesgaard). Not all of the references could be checked directly in available library collections. Thus, especially for some of the older references, we had to rely on the data in the *Astronomische Jahresbericht* or other secondary sources.

## Keywords

Radial Velocity Absolute Magnitude Globular Cluster Proper Motion Spiral Nebula## Preview

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## References

## 1885

- Cacciatore, G.
*Astr. Nachr.*,**112**, 387. Describes a 12^{m}or 13^{m}object near S And about 15″ to 18″ away.Google Scholar - Charlier, G. V. L.
*Astr. Nachr.*, 112, 389. Photometer measurement and position of S And.Google Scholar - Copeland, R.
*Astr. Nachr.*,**112**, 286. S And was observed as early as August 19 by I. Ward at 7.5^{m}and had a continuous spectrum. Gives position relative to nucleus.Google Scholar - Denning, W. F.
*Nature*,**32**, 465. General description of S And as seen through a 10-inch telescope.Google Scholar - Engelhardt, W.
*Astr. Nachr.*,**112**, 285. Day-by-day description of S And. Folio,*Astr. Nachr.*,**112**, 248. Observations of S And.Google Scholar - Gothard, E. V.
*Astr. Nachr.*,**112**, 390. Spectrum on September 6 and 12 of both S And and nebula. Both are continuous with no lines. Also photographs of the region.Google Scholar - Hartwig, E.
*Astr. Nachr.*,**112**, 245, 285, 355, 358, 360. Discovery of S And at Dorpat on August 31. Measured relative position with heliometer.Google Scholar - Huggins, W. and Rosse, Lord
*Nature*,**32**, 465. One-or-two-sentence reports of a dozen observations of the nebula since 1848. Describes spectrum of S And as continuous from C to F with bright lines probable.Google Scholar - Kammermann, A.
*Astr. Nachr.*,**112**, 299, 321, 387. Believes S And to be a new star, but not connected with nebula. Measured position relative to center.Google Scholar - Konkoly,
*Astr. Nachr.*,**112**, 286. No star observed on August 9 or 13. Podmaniesky observed a faint one on August 22. Observed spectrum without collimator lens on 254-mm telescope.Google Scholar - Lamp, E.
*Astr. Nachr.*,**112**, 245. Brightness and position of S And compared to star observed in nebula in 1836.Google Scholar - Oppenheim, H.
*Astr. Nachr.*,**112**, 245. Discovered S And independently while searching for comets.Google Scholar - Ricco, A.
*Nature*,**32**, 523. S And is 8^{m}with a continuous spectrum and suspected bright bands.Google Scholar - Schroder, C.
*Astr. Nachr.*,**112**, 246. Magnitude of S And; continuous spectrum with red brightest.Google Scholar - Schultz, H.
*Astr. Nachr.*,**112**, 302. Position and description of 10^{m}star in nebula in 1867 and 1875.Google Scholar - Seabroke, G.
*Nature*,**32**, 523. Spectrum of S And described. Spitaler, R.*Astr. Nachr.*,**112**, 284. Position of S And given.Google Scholar - Tempel, W.
*Astr. Nachr.*,**112**, 301. Nova not observed on August 16. Position and brightness on September 9 given.Google Scholar - Tromholt, W.
*Nature*,**32**, 579. Speculation about the nova being a very long period variable since a bright star in this nebula is told about in folklore.Google Scholar - Vogel, W.
*Astr. Nachr.*,**112**, 283, 302, 387. Summarizes previous observations of S And. It has a continuous spectrum, strongest in red and yellow, with a dark band between green and yellow and another in the blue between F and G. By September 10 star was down to 9^{m}. Continuous spectrum.Google Scholar - Ward, I.
*Astr. Nachr.*,**112**, 404. Claims first discovery of S And on August 19, 9.5^{m}at that time.Google Scholar - Wolf, M.
*Astr. Nachr.,***112**, 284. Established time of appearance of S And as between August 16 and 25.Google Scholar

## 1886

- Barnard, E. E.
*Astr. Nachr.*,**113**, 31. A small faint nebula near the northeast end of M31 is described.Google Scholar - Dreyer, J.
*Astr. Nachr.*,**113**, 270. Hartwig had claimed central part of nebula had changed. Dreyer argues that previous observers always disagreed about the central portion and no change had really occurred.Google Scholar - Engelhardt, W.
*Astr. Nachr.*,**115**, 252. No sight of nova this year; only its ll^{m}companion.Google Scholar - Engleman, R.
*Astr. Nachr.*,**113**, 269. Position of nova relative to ll^{m}star, and brightness (September 22: 8.92, to November 18: 10.8).Google Scholar - Gothard, E.
*Astr. Nachr.*,**115**, 252. Photographed in August 1885, but plates too dark to see nova. Spectrogram also taken, but not detailed. In October got better results with plate of different sensitivity. Spectrum of S And resembles that of a Wolf-Rayet star.Google Scholar - Gully, L.
*Astr. Nachr.*,**113**, 45. Reprint of article claiming discovery on August 17, 1885.Google Scholar - Hall, A.
*Nature*,**33**, 566. No parallax with respect to ll^{m}star from September 25 to February 7, when nova could no longer be seen at Washington.Google Scholar - Hall, M.
*Obs.*,**9**, 69. Description of drawing of nebula and comparison to other drawings. Brief account of nova.Google Scholar - Hartwig, E.
*Astr. Nachr.*,**113**, 21, 387. Changes in the center of the nebula. Defends observations against Dreyer’s attack.Google Scholar - Hasselberg, B.
*Astr. Nachr.*,**113**, 19. S And is like novae of 1848, 1866, and 1876. Argues that it is not connected with nebula.Google Scholar - Kövesligethy, R. von
*Astr. Nachr.*,**115**, 231, 303, 305, 307, 308. Variations in sharpness, color, and spectrum of nucleus of nebula where nova appeared. Compares brightness of nova with ll^{m}comparison star. The variations of the nebula prove that the nova was in the nebula.Google Scholar - Konkoly, N. von
*Astr. Nachr.*,**115**, 253, 267. Says that Bartfay is wrong; he was probably looking at ll^{m}star and not the nova.Google Scholar - Lamp, J.
*Astr. Nachr.*,**118**, 21. Position of nova relative to ll^{m}star and nucleus. Gives position of nucleus with respect to ll^{m}star.Google Scholar - Lynn, W. T.
*Obs.*,**9**, 69. Discusses discovery of the nebula. First noted on charts around 1500.Google Scholar - M G.
*Astr. Nachr.*,**113**, 23. Gives brightness (September 2, 7.95 to October 13, 10.04). Notes a systematic error in Charlier’s work.Google Scholar - M G.
*Astr. Nachr.*,**115**, 265. Poor observing, but no star at position of Nova (S And), although a concentration is observable.Google Scholar - Schönfeld, E.
*Astr. Nachr.*,**115**, 265. If there is a star near the nucleus now, it must be below ll^{m}.Google Scholar - Seeliger, H.
*Astr. Nachr.*,**113**, 353;*Nature*,**33**, 397. Mathematical theory of cooling of a hot ball of gas. Predicted results agree well with observations of S And. Original heating may have been due to stellar collision.Google Scholar - Sherman, 0. T.
*Astr. Nachr.*,**113**, 45. Spectrum of S And. Bright lines at λ5315 and 5575 and M, which is probably nebulous. Lines close to coronal lines.Google Scholar

## 1887

- Franz, J.
*Astr. Nachr.*,**118**, 123. Measured parallax of nova relative to three neighboring stars and found negative parallax, showing that nebula is behind these stars.Google Scholar - Roberts, I.
*M.N.R.A.S.*,**49**, 65, 121. Photographs of M31. Confirms nebular theory that it is a new solar system in the process of condensation.Google Scholar

## 1889

- Commons, A.
*Obs.*,**12**, 105. Discusses the excellent photograph of M31 by Roberts, which was first to show the spiral structure.Google Scholar

## 1890

- Gore, J.
*J.B.A.A.*, 1, 438. Gives angular dimensions, says it has no parallax, and proceeds to assign one, concluding that the nebula is too small to be another galaxy.Google Scholar

## 1891

- Roberts, I.
*M.N.R.A.S.*,**51**, 116. Photographs over a period of five years show variability of stellar nucleus.Google Scholar

## 1893

## 1898

- Barnard, E.
*Ap. J.*,**8**, 226, 262. Nucleus not changing. Observed changes probably due to seeing. Photographs do not show changes. Refers to: Rayet, M., Comptes Rendus, September 26, 1898; Rayet verifies Seraphimoff’s observation.Google Scholar - reported new star was not seen.Google Scholar
- Coddington, E.
*Pub. A.S.P.*,**10**, 45. Photograph with the Crocker telescope at Lick. Gives a good, concise history of observations.Google Scholar - Hartwig, E.
*Astr. Nachr.*,**148**, 11. Gives a review of the reported variations of nebula and presents a chart showing Nova 1885 and comparison stars.Google Scholar - Müller, J.
*Astr. Nachr.*,**147**, 287. Lists several observatories where the reported new star was not seen.Google Scholar - Pickering, E.
*Astr. Nachr.*,**147**, 363, and*Harvard Circular*,**34**. Comparison of photographs from 1893 to 1898 shows no variation of nucleus.Google Scholar - Seraphimoff,
*Astr. Nachr.*,**147**, 319, and*Nature*,**58**, 515, 605. Sharp central star, not condensation, of ll^{m}; proves variability of nucleus.Google Scholar - Scheiner, J.
*Astr. Nachr.*,**148**, 325. Photographic spectrum indicative of a cluster of solar-type objects.Google Scholar

## 1899

- Barnard, E.
*Obs.*, 22, 376. The nebula is farther than the fixed stars.Google Scholar - Hale, G.
*Ap. J.*, 9, 184. Negative parallax for nebula. Speculates as to whether the comparison stars are in the nebula.Google Scholar - Hussey, W. J.
*A.J.,***19**, 152, and*Obs.*,**22**, 137. Note concerning the central condensation of M31; brightness and spectrum.Google Scholar - Wilson, H. C.
*Pop. Astr.*,**7**, 507. Description and reproduction of recent photographs with a brief history of earlier photography. Tells of difficulties in obtaining parallax.Google Scholar

## 1900

- Roberts, Mrs. Isaac, “Photographs of Stars, Star Clusters, and Nebulae,” Vol. II, Knowledge Office, London. Plates taken with a 20” reflector, with descriptions. Plates 10–18 are of spiral nebulae, including four exposures of M31. Author finds that a 10-hour exposure shows no more stars than a 90-minute exposure — her conclusion is that the part of the universe that we can see from the Earth is finite. Tentative suggestion that stellar systems may evolve from nebulous matter, since certain groups of stars seem to fall on lines or curves, indicating more than a casual association.Google Scholar

## 1902

- Roberts, Mrs. Isaac,
*J.B.B.A.*,**12**, 109. Describes another plate of M31. Nucleus resembles a small bright star surrounded by nebulosity. She cannot tell for sure what stars in the area are connected with it.Google Scholar

## 1904

- Asmussen, O.
*B.S.A.F.*,**18**, 49. Reproduction of a photograph taken by Nielsen in Copenhagen.Google Scholar - Ritchey, G. W.
*University of Chicago Decennial Publications*,**8**, 389. An excellent photo of M31 and a brief description of spiral structure.Google Scholar - Wesley, W. K.
*M.N.R.A.S.*,**64**, 237. Author concludes that spurious details in Ritchey’s photographs had not been introduced by plate processing.Google Scholar

## 1905

## 1907

- Götz, P.
*Heidlb. Astrophys. Publ.*,**3**, Nr. 1–39. Positions and magnitudes for 1,259 stars involved in the Andromeda Nebula, together with the positions of 54 recognizable points, followed by a detailed description of the nebula, a discussion of the relation of the star-density to the form and brightness of the gaseous mass, and the results of a statistical investigation of the distribution of stars. All stars are fainter than the 9th magnitude, 64 fainter than 16th.Google Scholar - Bohlin, K.
*Astronomiska Iakttagelser och Undersokningar a Stockholms Observatorium*,**Vol III**, 4, p. 66. From 15 photos of M31, three separate determinations of the parallax were made, with a mean of 0.17″.Google Scholar

## 1908

- Bererich, A.
*Nat. Rund.*,**23**, 1-3,*Weltall*,**8**, 147. Description and discussion of work of Götz and Bohlin.Google Scholar - Denning, W. F.
*Pop. Astr.*,**16**, 197. Using Bohlin’s parallax he derives a distance for M31 of 1.13 × 1014 miles and a linear extent of 3.6 × 1012 miles.Google Scholar - Gore, J. E.
*Know. N. S.*, 5, 71-74. Discusses distance, diameter, thickness, density, volume. Decides that the parallax of Bohlin is too large, for it makes M31 have a mass of 8 × 109 suns. Rejects the external galaxy notion. He explains the nova of 1885 according to a theory of collision and cooling.Google Scholar - Schroeter, J.
*Fr. Naturen*,**32**, 18. Article in Norwegian reviewing work of Roberts, Bohlin, and Götz.Google Scholar - Wolf, M.
*M.N.R.A.S.*,**68**, 626. Discusses the lengths of axes and the position angles of 52 oval nebulae.Google Scholar

## 1909

- Fath, E. A.
*Lick Bull.*,**149**, 71. Using the Crossley reflector fitted up as a nebular spectrograph, spectra of M31 and other spirals are determined. Spectrum of M31 found to be “of solar type,” with 14 identifiable absorption lines and an intensity maximum at λ4640. Author unable to understand why all the stars in M31’s nucleus should be of one spectral type. Also derives from Bohlin’s parallax the result that the stars in the nucleus are the size of asteroids.Google Scholar - Kapteyn, J.
*Ap. J.*,**30**, 284. In a footnote at the end of this article, Kapteyn uses a recent observation by H. D. Babcock on M31 to strengthen his conclusion that “there must be an appreciable amount of absorption in space.” Babcock’s observation compared two photos of M31, one through a red glass plate, to conclude that M31 was 1 magnitude redder than a star of the same spectrum.Google Scholar

## 1911

- Sutherland, A.
*Ap. J.*,**33**, 251. Author expresses Bode’s Law mathematically as the sum of two logarithmic spirals. This suggests to him that M31, the solar system, and Saturn’s rings are all similar examples of a fundamental law of nature governing the condensation of matter into systems.Google Scholar

## 1912

- Wolf, M.
*Sitzungsberichte der Heidelb. Akad. der Wissenschafter Abt. A 1912*3 Abhandlung, Nr. 15. Wolf’s studies of spiral spectra, in particular M31, agree with those of Fath.Google Scholar

## 1913

- Reynolds, J. H.
*M.N.R.A.S.*,**74**, 132-136. Measurement of plate density as a function of distance from the center. Obtains a central bulge and wings to which the curve (x +1)2 y = const. is a good fit. Believes that the nucleus is one star, much involved with the surrounding nebulosity. He feels that if the nucleus contained more than one star, we should be able to resolve them photographically. The inverse-square nature of the light curve lends support to the hypothesis that this is simply a reflection nebula — measures in polarized light are needed.Google Scholar - Slipher, V. M.
*Lowell Bull. #58*,**2**, 56. Discusses how to build a spectrograph for a faint source. Gets a mean velocity for M31 of −300 km/sec. This high velocity suggests to him that a study of proper motions of spirals should be done. Proposes as a solution to the origin of the 1885 nova the hypothesis that the nebula “encountered a dark star” in its rush towards us at such high velocity.Google Scholar

## 1914

- Slipher, V. M.
*Pop. Astr.*,**23**, 21. Summary of work on nebulae, including rotation of M31. Found rotation greater near the nucleus, inclination of the lines indicating a speed of 100 km/sec at 20″ from the nucleus. Author states that the spectrum of M31 shows no composite features such as those shown by star clusters.Google Scholar

## 1915

- proper motion studies. The results for nebulae (including M31) is an average of 0.033″, which, using Slipher’s velocities, implies distances on the order of 10,000 light years. No evidence has been found for rotation through positional measurements.Google Scholar

## 1917

- Barnard, E. E.
*A.J.*,**30**, 175. Over a period of seven years the proper motions of M31 are undetectable. Positional values are available since 1836 but are too inaccurate to be used.Google Scholar - Lundmark, K. and Lindblad, B.
*Astr. Nachr.*,**205**, 161;*Ap. J.*,**46**, 206. Effective wavelengths are obtained and converted to spectral types and color indices. M31 is G4.Google Scholar - Ritchey, G. W.
*Pub.A.S.P.*,**29**, 257. Discovery of a faint nova. Shapley, S.*Pub.A.S.P.*,**29**, 213. Discovery of a faint nova.Google Scholar

## 1918

- Curtis, H. D.
*Lick Pub.*,**13**. Author emphasizes that dark lanes are often found in spirals, formed by obscuring matter and not just an absence of stars.Google Scholar - Pease, F. G.
*Proc. Nat. Acad. Sci.*,**4**, 21. (Mt. Wilson Comm. 51.) Obtains a radial velocity of −316 km/sec. Rotation measures required an exposure of 79 hours on the 60”. His results along the major axis are fairly well represented by a straight line, implying that any theory of orbits obeying an inverse square law must be abandoned.Google Scholar - Ritchey, G. W.
*Pub.A.S.P.*,**30**, 162. Three additional novae discovered. Sanford, R.*Pub.A.S.P.*,**30**, 341. Two more novae discovered.Google Scholar - Van Maanen, A.
*Pub.A.S.P.*,**30**, 307. A very carefully done parallax of M31 gives 0.004 ± 0.005″.Google Scholar

## 1920

- Seares, F. H.
*Ap. J.*,**52**, 162. Calculates the surface brightness of the Galactic system as viewed from a distant point in the direction of the galactic pole for various distances from the center and finds the brightness of the central part to be of visual magnitude 23 per square second of arc, whereas Andromeda is more than 100 times brighter. Concludes that our Galaxy is not a typical spiral.Google Scholar

## 1921

- Reynolds, J. H.
*Obs.*,**44**, 368. M31 shows a*recession*of 278 km/sec. Photographs show very little ultraviolet in M31. The angular dimensions of M31 are roughly 130′ × 40′.Google Scholar - Slipher, V. M.
*Pop. Astr.*,**29**, 272. Evidence for the rotation of NGC 224 was obtained from the inclination method,*i.e.*, keeping the slit of the spectrograph over the major axis of the nebula.Google Scholar

## 1922

- Doig, P.
*J.B.A.A.*,**32**, 138. Gives a short account of the novae in M31. Taking the absolute magnitude of the nova of 1885 as −14.0, gets a distance of 540,000 light years and a diameter of about 18,000 light years. Comes to the conclusion that the possibility is large enough to admit the hypothesis that it is an external universe.Google Scholar - La Place-Janssen and Haarh, G. E. H.
*Astr. Nachr.*,**215**, 285. Discusses the parallax of the Andromeda Nebula.Google Scholar - Opik, E.
*Ap. J.*,**55**, 406. Assumes that the ellipsoidal shape of the inner parts of the nebula is due to rotation, and then applies Kepler’s third law and gets an estimate of the distance to be 450,000 parsecs.Google Scholar

## 1923

- Lundmark, K.
*Pub.A.S.P.*,**35**, 95. Assuming that the mean absolute magnitude of the 22 known novae in M31 is equal to that for the novae in Sagittarius, he gets the distance for M31 to be 63 times the distance for the Sagittarius region. This gives a distance of about 4 × 106 light years.Google Scholar

## 1924

- Reynolds, J. H.
*M.N.R.A.S.*,**85**, 142. Finds that spirals vary greatly in the matter contained, both in their nuclei and arms and concludes that though M31 and M33 may be compatible in dimensions with our Galaxy, most spirals are relatively quite insignificant.Google Scholar

## 1925

- Hubble, E. P.
*Obs.*,**48**, 139;*Pop. Astr.*,**33**, 252. From the observed Cepheid variables in M31 a Shapley period-luminosity curve has been constructed on the basis of visual magnitudes. From these a distance of 285,000 parsecs (= 930,000 light years) is obtained. Assumptions are (1) variables are actually connected with spirals, (2) no serious amount of absorption due to amorphous nebulosity is in the spiral, and (3) the nature of Cepheid variation is uniform throughout the observable portion of the universe.Google Scholar - Jeans, J. H.
*M.N.R.A.S.*,**85**, 531. Considers the hypothesis that nebular condensations are formed by gravitational instability in a gas. Up to 90% of matter in the arms might be in solid or liquid state. Assuming the lenticular shape of M31 to be due to rotation, gets a period of 5.7 × 1014 sec, a mean density of 9 × 10−22 gm/cm3, a diameter of the nucleus of 1021 cm and a mass of 5 × 1042 gm. Suggests that M31 exemplifies a state intermediate between the typical spiral and the Galactic system.Google Scholar - Landmark, K.
*M.N.R.A.S.*,**85**, 865. Discusses various methods by which the distances of the spiral nebulae can be estimated. Charlier showed the distance of NGC 224 to be 28 times the diameter of the Galactic system. On the assumption that Galactic and Andromeda nebulae have equal absolute magnitudes, Lundmark finds the distance of NGC 224 to be 32 times the diameter of the Galactic system in good agreement.Google Scholar

## 1926

- Lee, O. J.
*Pop. Astr.*,**34**, 492. Gives an account of proper motion studies by various people and gets 0″.0184 for the annual proper motion from his own data.Google Scholar - Reynolds, J. H.
*M.N.R.A.S.*,**87**, 112. Assuming that the nebula is roughly circular, a comparison of the major and minor axes of the apparent ellipse shows that the inclination is about 70°. It is of massive type with arms of considerable breadth, one arm more irregular than the other. The smaller globular nebula NGC 221 has the same radial velocity as M31 and so they may be connected. Star counts show 10 times as many stars at the extremities of the ellipse as near the center.Google Scholar

## 1927

- Lundmark, K. and Ark, F.
*Mat. Astron. och Fysik.*,**20b**, No. 3. Assuming the dispersion in the absolute magnitudes of the separate stars is small, it is possible to compute the distances without making any assumption as to their size or total brightness. For 30 objects, including M31, gives total magnitude, apparent diameters, magnitudes of brightest stars, relative distances and parallaxes.Google Scholar - Luyten, W. J.
*Harvard Bull.*,**851.**Two variable stars found in the nebula varied from 16.5^{m}to 15.3^{m}and 13.5^{m}to 14.5^{m}.Google Scholar

## 1928

- Duncan, J. C.
*Pub.A.S.P.*,**40**, 347. Four novae were discovered on July 16, 1928. Their positions from the nucleus and magnitudes are given.Google Scholar - Markov, A.
*Astr. Nachr.*,**234**, 329. From the surface brightness of 19 nebulae, including M31, he comes to the conclusion that the most probable explanation of the spirals is that they are galaxies similar to ours.Google Scholar

## 1929

- Hubble, E. E.
*Ap. J.*,**69**, 103. Results of a comprehensive study. Fifty variables and 63 novae were found. The mass density of M31 appears to be about one sun per 20 cubic parsecs and luminosity density about 0.9 magnitudes per cubic parsec. An approximate comparison of sizes, masses, luminosities and densities suggest that the Galactic system is much larger than M31.Google Scholar - Lundmark, K. and Ark, F.
*Mat. Astron. och Fysik*,**21a**, 9 and**21a**, 10. From spectroscopic observations of rotation in spiral nebulae, including M31, the masses and absolute magnitudes are deduced.Google Scholar - Perrine, C. D.
*Astr. Nachr.*,**236**, 329. Gives distance, diameter, and other properties for spiral nebulae, including M31.Google Scholar

## 1930

- Vinterhansen, J. M.
*Nordisk Astronmisk. Tiddskrift Kobenhavn*,**11**, 1. A discussion of M31 in light of the new distance determinations due to Lundmark and Hubble.Google Scholar

## 1931

## 1932

- Hubble, E.
*Ap. J.*, 76,**44**. Identification of 140 nebulous objects in or close to the border of M31 which, from numbers distribution and radial velocities are presumed to be globular clusters associated with the spiral. Comparison is made with globular clusters in our Galaxy and the Magellanic Clouds and similar objects in other nebulae.Google Scholar - Reynolds, J. H.
*Obs.*,**55**, 301. A discussion of past observations of possible globular clusters.Google Scholar

## 1934

- Baade, W. and Zwicky, F.
*Proc. Nat. Acad. Sci.*,**20**, 254. A distinction is made between common and supernovae. Physics of novae are discussed and S And is used as an example of a supernova.Google Scholar - Shapley, H.
*Harvard Bull*,**895**, 19. Uses densitometer to get values for the major axis of 194 arcmin and of the minor axis of 16 arcmin.Google Scholar - Stebbins, J. and Whitford, A. E.
*Proc. Nat. Acad. Sci.*,**20**, 93. Found photoelectric diameter larger than photographic; size more than doubled in the direction north and south from the nucleus.Google Scholar

## 1935

- Bernheimer, W. E.
*Wien Urania Zirk 2*,**Nr 4**. Observations of Stebbins and Whitford, Shapley and Vocca are discussed, compared and analyzed and a proposal is made for a set of better observations of the diameter.Google Scholar - Vocca, P.
*Memorie della Societa Astrnomica Italiania*,**9**, 75. A confirmation of Hubble’s work on the dimensions of M31.Google Scholar - Zanstra, H.
*Naturwissenschaften*,**23**, 867. Observations of S And fit Baade and Zwicky’s hypothesis about novae.Google Scholar

## 1936

- Hubble, E.
*Realm of the Nebula*, Yale University Press, New Haven. General summary of data known about the nebula.Google Scholar - Payne-Gaposchkin, C.
*Ap. J.*,**83**, 245. Examines the records of the spectrum of S And and arranges them in a table in chronological order. From the table one can see that the nova spectrum was at first practically continuous and later showed bright lines of no very great intensity. There is also a table of color observations.Google Scholar - Whitford, A.
*Ap. J.,***83**, 424. Integrated magnitudes measured by a photoelectric photometer, particularly for the Andromeda Nebula. With m-M of 23.0 he gets M of −17.5.Google Scholar

## 1937

- Hogg, F. S.
*J.R.A.S. Can.*,**31**, 351. Discusses Zwicky’s search for supernovae and mentions S And.Google Scholar - Lindblad, B.
*Vierteljahrsschrift der Astronomischen Gesellschaft*,**72**. Gives results of a photometric study of the distribution of the dark material in the nebula.Google Scholar - Redman, R. O. and Shirley, E. G.
*M.N.R.A.S.*,**97**, 416. Photometry provides luminosity distributions along the axes.Google Scholar

## 1938

- Baade, W.
*Ap. J.*,**88**, 285. Compiles photometric data for 18 supernovae,*i.e.*, those known at the end of 1937. Former estimates have been replaced by photometric magnitudes after a redetermination of theGoogle Scholar - magnitudes of comparison stars on the international system. Gets −15 for S And.Google Scholar
- Babcock, H. W.
*Pub.A.S.P.*,**50**, 174. A linear velocity of rotation of 90 km/sec in the plane of the spiral is measured at*r*of 4′. It is constant at 150 km/sec until 30′. Systemic velocity is −300 km/sec.Google Scholar - Zwicky, F.
*Ap. J.*,**88**, 529. Discusses the frequency of supernovae. A footnote describes a hypothetical case of the calculation of too large a frequency of supernovae for M31.Google Scholar

## 1939

- Becchini, G. and Gratten, L.
*Memorie della Astronomica Italiania*,**18**, 303. A statistical study that shows that the novae in our Galaxy agree in frequency with those in M31.Google Scholar

## 1940

- Babcock, H. D.
*Lick Bull. 498*,**19**, 41. Observations of continuous solar-type spectrum of unresolved stars and of diffuse and emission nebulosities give a complete rotation curve. Finds the mass luminosity ratio and compares M31 with our Galaxy.Google Scholar - Zwicky, F.
*Rev. Mod. Physics*,**12**, 66. S And is mentioned as an example of the recognition of supernovae as a separate class of novae.Google Scholar

## 1941

- Wyse, J. D. and Mayall, N. U.
*Pub.A.S.P.*,**53**, 269. The distribution of mass in M31 and M33 was determined by comparing a disk model with observed rotation curves.Google Scholar

## 1942

- Danver, G. G.
*Ann. Obs. Lund.*,**10**, 7. M31 included in discussion of spiral arm patterns.Google Scholar - Lindblad, B.
*Stockholms Obs. Ann.*,**14**, 3. Using Öhman’s measures of polarization of a small dark cloud near the nucleus of M31, the conclusion is reached that the brighter edge of the nebula is the nearer.Google Scholar - Öhman, Y.
*Pub.A.S.P.*,**54**, 72 and*Stockholms Obs. Ann.*,**14**, 4. Polarization of about 3% observed in a small dark cloud near the nucleus of M31. This polarization may be used to support Lindblad’s conclusion about the orientation of the nebula.Google Scholar - Wyse, J. D. and Mayall, N. U.
*Ap. J.*,**95**, 24. M31 and M33 are assumed to be composed of flat disks with surface densities represented by 5th-degree polynomials. Assuming circular motion, the observed rotation curve gives the mass distribution. The solutions show little tendency toward central condensation. In both cases the average space density derived from the surface density is about two solar masses per cubic parsec in the main bodies. The total mass of M31 is 9.5 × 1010 solar masses.Google Scholar

## 1943

- Eigenson, M.
*Russian A. J.*,**4**, 5. The rotation of M31 as observed by Babcock is interpreted in terms of a spherically distributed uniform system in order to deduce conclusions about our own Galaxy.Google Scholar - Williams, J. and Hiltner, W.
*Pub. Obs. Univ. Michigan*,**8**, 103. Used an 18” Palomar Schmidt plate to construct isophotes of M31. The length of the major axis was found to be at least 400′. Faint outer regions tended to spiral in the opposite sense from the arms.Google Scholar

## 1944

- Baade, W.
*Ap. J.*,**100**, 137. Photographs on red-sensitive plates resolve the central region of M31 and the companions M32 and NGC 205 into stars. The brightest stars there have photographic magnitudes of 21.3 and color indices of +l^{m}.3.Google Scholar - Chalonge, D.
*Bull. Soc. Astron. France*,**58**, 139. A short article on recent research on the Andromeda Nebula.Google Scholar - Leontovski, M.
*Bull. de l*’*Inst. Astron. (Leningrad)*,**53**, 1. Discusses the structure of Stebbins’ regions in M31.Google Scholar

## 1945

- Seyfert, K. and Nassau, J. J.,
*Ap. J.*,**101**, 179. Star counts on blue-sensitive plates made with 24″ Schmidt show reasonable agreement with isophotal contours. The luminosity distribution in the main body is similar to that for the solar neighborhood in the observed range of absolute magnitudes. The thickness from high luminosity stars was estimated to be of the order of 200 pc.Google Scholar - Seyfert, K. and Nassau, J. J.
*Ap. J.*,**102**, 377. Gives photographic magnitudes for 212 of the 249 nebulous objects in M31 found by Hubble and Baade. The mean absolute magnitude of these objects is about −5.0.Google Scholar

## 1946

- Lindblad, B. and Brahde, R.
*Ap. J.*,**104**, 211. The orientation of the Andromeda Nebula is inferred from the relative distributions of novae and variables compared to globular clusters.Google Scholar

## 1947

- Parenago, P. P.
*Russian A. J.*,**24**, 178. Babcock’s rotation curve for M31 is interpreted as being due to Baade’s Population II in the center and Population I in the outer parts; each population having its own velocity curve.Google Scholar

## 1948

- Fricke, W.
*Die Naturwis.*,**35**, 52. Discusses the structure of the nucleus of M31 and photometry, rotation, and internal motions of spiral nebulae.Google Scholar - Lindblad, B.
*Stockholms Obs. Ann.*,**15**, 4. The orientation of the nebula is discussed using the distribution of globular clusters.Google Scholar - Mayall, N. U.
*A. J.*,**54**, 44. Inclination of lines in the spectrum of M31 imply rotation periods for the outer parts in the range 60 to 220 × 106 years.Google Scholar - Parenago, P. P.
*Russian A. J.*,**25**, 306. The similarity of our Galaxy to M31 is discussed with respect to rotation and shape of spiral arms.Google Scholar

## 1949

- Artyukina, N. M.
*Proc. State Astron. Inst. (USSR)*,**16**, 93. Reviews work that has been done on the distance, Cepheids, mass, etc.Google Scholar - de Vaucouleurs, G.
*Obs.*,**69**, 150. Suggests that M31 is close enough that the variation of distance across the nebula may be sufficient for a detectable variation of the period-magnitude relation for the Cepheids from one side to the other.Google Scholar - Hartwig, G.
*Die Sterne*,**25**, 7. This article deals with Population II stars in elliptical nebulae and the nucleus of M31.Google Scholar

## 1950

- Dombrowskiy, W. A.
*Pub. Astr. Obs. (Leningrad)*,**15**, 166. Microphotometry of nebulae, including M31.Google Scholar - Holmberg, E.
*Lund. Medd. (2)*,**128**, 56 pp. Gives photometry and light and color distributions.Google Scholar