1. Galactic Astronomy 銀河物理学特論 I Lecture 1-3: Morphological properties of galaxies Seminar: Strateva et al. 2001, AJ, 122, 1861
Lecture:
2011/10/31

2. Morphological Classification
SDSS galaxies
Buta, 2011, arXiv:

3. Morphological Classification
Sequence of elliptical galaxies
Ellipticity increases along the sequence, and goes up to E7.
Morphological Classification
Buta, 2011, arXiv:
Effect of inclination angle, viewing angle
Barred structure becomes difficult to be identified, ex. Milkey way galaxy.
Edge-on galaxies
Disk structure becomes thinner along the Hubble sequence.

4. Morphological Classification
Barred vs. non-Barred galaxies
Early-type barred galaxies sometimes show ring-like structure due to the orbital resonance (共鳴).
Morphological Classification
Buta, 2011, arXiv:

5. Physical parameter along Hubble sequence
Roberts & Haynes
1994, ARAA, 32, 115

6. Physical parameter along Hubble sequence
Roberts & Haynes
1994, ARAA, 32, 115

7. Sersic profile fitting
I(R)=Ie exp(-bn((R/Re)^(1/n)-1)
With n=1 then I(R)=I’ exp(-bn(R/Re)) : exponential profile
With n=4 then I(R)=Ie exp(-bn((R/Re)^1/4-1)) : r1/4 profile
Exponential and r1/4 profiles are handled with one parameter n.
Graham & Driver 2005

8. Luminosity Function of Each Morphological Type
The dependence of the galaxy luminosity function is examined with ~1,500 galaxies from SDSS. Bright-end of the LF is dominated by E/S0 galaxies. Irr galaxies only appear in faint-end of the LF. Classification is also done with concentration parameter C=r50/r90.
Nakamura et al.
2003, ApJ, 125, 1682

9. Bulge vs. Pseudo-bulge
Bulge-like structures of late-type disk galaxies can be fitted with low Sersic index profile ~1, i.e. exponential-law. Such bulges are called psuedo-bulge.
Buta, 2011, arXiv:
Kormendy 2004, ARAA, 42, 603

10. Bulge vs. Pseudo-bulge
Dynamics of pseudo-bulge can be dominated by rotation.
Kormendy 2004, ARAA, 42, 603
Laurikainen et al. 2007, MNRAS, 381, 401

11. Fraction of Barred galaxies among disk galaxies
Nair & Abraham
2010, ApJL, 714, L260

12. Fraction of Barred galaxies among S/Irr galaxies
Lee et al. 2011, arXiv:

13. Bar-structure and nuclear activity:
Bar-structure can induce transportation of gas to the nuclear region (Noguchi 1988, A&A, 203, 259). Optical images of Narrow-Line Seyfert 1s (NLSy1) show that bar-structure is common among NLSy1.
Ohta et al. 2007, ApJS, 169, 1