The following contributions were included in the
2000 Annual Report of the Kapteyn Astronomical Institute
of the Rijksuniversiteit Groningen, p. 46

A spectrophotometric study of 196 galaxies in the local field

    The interpretation of observations of distant galaxy samples is limited by our partial knowledge of the spectrophotometric properties of the local field galaxy population. In particular, the range in properties as a function of galaxy luminosity has not been studied systematically. To remedy this situation, R.A. Jansen, D.G. Fabricant (CfA, Cambridge), M. Franx (Leiden Observatory), N. Caldwell (CfA, Cambridge and F.L. Whipple Observatory, Amado), and S.J. Kannappan (CfA, Cambridge) obtained optical spectrophotometric and photometric observations for 196 nearby galaxies that form a representative sample of the local field population. The galaxies span the entire Hubble sequence in morphological type, as well as a wide range of luminosities and colors.
    In collaboration with D.G. Fabricant and N. Caldwell nuclear and integrated spectra were obtained for each of the selected galaxies, complemented by U, B and R filter surface photometry. Kannappan and Fabricant have secured optical internal kinematics (rotation curves and stellar velocity dispersions) for the same galaxies. All observations were obtained at the F.L. Whipple Observatory.
    The main goal of this program is to provide a comparison sample for high redshift studies and to study the variation in star formation rates, star formation history, excitation, metallicity, and internal kinematics over a large range in galaxy luminosity and morphological type -- both globally and as a function of radius within a galaxy.
    In his Ph.D. thesis, Jansen described the galaxy selection, the observations and data reduction, and presented two atlasses of the primary data products: one of the images and radial profiles of surface brightness and color, the other of the nuclear and integrated spectra. Furthermore, the first results of a study of the spectrophotometric properties of the sample were discussed, focusing on the use of [O II] as a tracer of star formation and on quantitative measurements of galaxy morphology. Figure 18 shows that the observed luminosity dependence of the [O II] / H\alpha ratio results from the combined effects of differences in extinction and metallicity. These systematic differences need to be taken into account when using [O II] as a tracer of current star formation.
    Parts of this work were performed by Jansen while a Predoctoral Fellow (1996 - 1998) at the Harvard-Smithsonian Center for Astrophysics, and while employed as ESA Internal Research Fellow at ESTEC (2000 - ). The full data set is planned to be made accessible to the general community in electronic format via the Nearby Field Galaxy Survey homepage at URL: .

Fig.18a Fig.18b Fig.18c

Figure 18: The observed luminosity dependence of the ratio of the [O II and H\alpha emission lines (a) can be attributed to the combined effects of systematic differences from galaxy to galaxy in internal extinction (b) and metallicity (c).

Papers in scientific journals, books

Jansen, R.A, Fabricant, D., Franx, M., & Caldwell, N. ``Spectrophotometry of Nearby Field
        Galaxies: The Data'', Astrophys. J. Suppl. Ser. 126, 331, 2000.
Jansen, R.A, Franx, M., Fabricant, D., & Caldwell, N. ``Surface Photometry of Nearby Field
        Galaxies: The Data'', Astrophys. J. Suppl. Ser. 126, 271, 2000.

Conference Papers

Jansen, R.A., ``The Nearby Field Galaxy Survey; A Spectrophotometric and Photometric Study
        of 196 Galaxies in the Local Field'', in: Building Galaxies: from the Primordial Universe to the
       Present (eds. F. Hammer, T.X. Thuan, V. Cayatte, B. Guiderdoni, & J. Trân Thanh Vân), Proc.
        XIXth Moriond meeting (Les Arcs, France, March 13-20, 1999)
, Singapore, World Scientific,
        p.33, 2000.


Jansen, Rolf A., The Nearby Field Galaxy Survey, Promotores: Prof. dr. M. Franx, &
        Dr. D.G. Fabricant, Referent: Dr. N. Caldwell, Proefschrift Faculteit Wiskunde en
        Natuurwetenschappen, Rijksuniversiteit Groningen (28-11-2000)
, 152 pgs., 2000.

Popular Lectures

R.A. Jansen, ``Evolutie van Sterrenstelsels''
        14 Dec. - Haarlemse Weer- en Sterrenkunde Kring, Haarlem

Last updated: Jun 26, 2001 (minor style change)