The Galaxy Zoo View of the Hubble Sequence

The working document for a paper on the “Galaxy Zoo view of the Hubble sequence”.

Ross’s repository with figures: https://github.com/RossHart/Hubble_sequence

To do list (also see “Issues”):

• References to review more carefully:

  • Sandage 2005: http://adsabs.harvard.edu/abs/2005ARA%26A..43..581S
  • de Vaucouleur 1959 In Handuch der Physik, Vol. 53, ed. S Flugge p 275, Berlin: Springer-Verlag (! - a RH94 ref, hope it’s not in German)
  • Sandage 1961. The Hubble Atlas of Galaxies, Washington: Carnegie Inst. Washington.
  • Sandage 1975. In {\it Stars and Stellar Systems}, Vol 9. ed. A. Sandage, M. Sandage, J. Kristian, p1, Chicago: Univ. Chicago Press.
  • Buta 1992 (may need help here - I bet Portsmouth Library will not have these - found in the citation list of Roberts & Haynes)
    • Buta, R. in {\it Morphological and Physical Classification of Galaxies}, ed. G. Longo, M. Capaccioli, G. Busarelo, p1, Dordrecht:Kluwer
    • Buta R. See Thuan et al. 1992 p 3 (?) - Thuan et al. 1992, Physics of Nearby Galaxies. Gif-sur-Yvette: Frontiers
  • Buta, Corwin, & Odewahn 2007
  • Using B/D and calling it morphology: \bibitem[Lofthouse et al.(2017)]{2017arXiv170901519L} Lofthouse, E.~K., Kaviraj, S., Smith, D.~J.~B., \& Hardcastle, M.~J.\ 2017, arXiv:1709.01519

• Discussion of the significance of pitch angle (lack of) correlation with bulge size

• Add references and acknowledgements from the literature search

• what value of H0 for the magnitudes?

• Check numbers in Table 2.

• Add Kennicutt 1981, 1998

Notes

Comments from Bill at GZ10:

• Not how Sandage described the process. Sandage had larger scale plates.
• de Vaucouleur did tend to favour bulge size.

Comments from Bill by email:

“Let me cheerlead for the idea of revisiting the 2014 draft. Tis is a major thing in classical morphology. We might be able to consider whether there are visual biases from photographs that could have led to Hubble’s view (and in fact trace where that appeared historically), since use of bulge prominence predates practically all photographic photometry and quantitative decomposition. For example, there are spirals with very luminous bulges but large scale length for the bulge (NGC 3521 was my standard example, but the amateur deep imaging coordinated by Gonzalez-Delgado may show that to be tidal structure rather than a genuine relaxed bulge). NGC 7331 is kind of similar in that way.”

Kormendy \& Bender (2012) - “everything that is not forbidden is mandatory” (when it comes to galaxy evolution processes).

Hart et al. 2016: “Galaxy stellar mass is known to correlate with galaxy mor- phology (Bamford et al. 2009; Kelvin et al. 2014b), and spi- ral galaxy Hubble type (Mun ̃oz-Mateos et al. 2015).”

Dobbs & Baba 2015 “Although the pitch angle is histor- ically used to classify galaxies according to the Hubble sequence, the differences in spiral arm shape, i.e. the pitch angle of the spiral arms appears to be most de- pendent on the maximum rotation velocity, and thus the local shear in the disc, rather than the global mass dis- tribution (Kennicutt, 1981; Kennicutt & Hodge, 1982; Garcia Gomez & Athanassoula, 1993; Seigar & James, 1998; Seigar et al., 2006). For example Figures 8 and 10 of Kennicutt (1981) show that the pitch angle corre- lates much better with the maximum rotational velocity than the properties of the bulge. However there is still considerable scatter (see Figure 7 of Kennicutt 1981)”

From Mel’s red spiral paper: most galaxies tend to ex- ist in one of two populations: blue, late-type disks exhibiting active star formation, and red, early-type ellipticals show- ing little to no signs of recent star formation (Strateva et al. 2001; Baldry et al. 2004; Correa et al. 2017).