Galbany, Lluis, Miquel, Ramon, Oestman, Linda, Brown, Peter J., Cinabro, David, D'Andrea, Chris B., Frieman, Joshua, Jha, Saurabh W., Marriner, John, Nichol, Robert C., Nordin, Jakob, Olmstead, Matthew D., Sako, Masao, Schneider, Donald P., Smith, Mathew, Sollerman, Jesper, Pan, Kaike, Snedden, Stephanie, Bizyaev, Dmitry, Brewington, Howard, Malanushenko, Elena, Malanushenko, Viktor, Oravetz, Dan, Simmons, Audrey and Shelden, Alaina (2012), "TYPE Ia SUPERNOVA PROPERTIES AS A FUNCTION OF THE DISTANCE TO THE HOST
GALAXY IN THE SDSS-II SN SURVEY", ASTROPHYSICAL JOURNAL, 755, 2.
Abstract: We use Type Ia supernovae (SNe Ia) discovered by the Sloan Digital Sky
Survey-II SN Survey to search for dependencies between SN Ia properties
and the projected distance to the host-galaxy center, using the distance
as a proxy for local galaxy properties (local star formation rate, local
metallicity, etc.). The sample consists of almost 200 spectroscopically
or photometrically confirmed SNe Ia at redshifts below 0.25. The sample
is split into two groups depending on the morphology of the host galaxy.
We fit light curves using both MLCS2k2 and SALT2, and determine color
(A(V), c) and light-curve shape (Delta, x(1)) parameters for each SN Ia,
as well as its residual in the Hubble diagram. We then correlate these
parameters with both the physical and the normalized distances to the
center of the host galaxy and look for trends in the mean values and
scatters of these parameters with increasing distance. The most
significant (at the 4 sigma level) finding is that the average fitted
A(V) from MLCS2k2 and c from SALT2 decrease with the projected distance
for SNe Ia in spiral galaxies. We also find indications that supernovae
(SNe) in elliptical galaxies tend to have narrower light curves if they
explode at larger distances, although this may be due to selection
effects in our sample. We do not find strong correlations between the
residuals of the distance moduli with respect to the Hubble flow and the
galactocentric distances, which indicates a limited correlation between
SN magnitudes after standardization and local host metallicity.
Keywords: galaxies: general; galaxies: photometry; supernovae: general