Galaxy Measurements This final analysis section discusses the galaxy measurements used in the results and how they were obtained. The goal of this project is to explore the properties of SNe Ia in extreme environments. To determine if the SNe are in an extreme environment the separation of the SNe must be known. This separation describes the distance between the SNe Ia and the centre of its host galaxy. The locations of SNe and the host galaxy in the sky are described by the right ascension and declination. Right ascension is the equivalent of longitude and is measured in a full circle from the vernal equinox and therefore can have values between 0 and 360 degrees. The declination is comparable to latitude, with points south of the celestial …show more content…
Table displaying the SDSS filters and corresponding wavelength at which they are most sensitive [58]. The magnitude values obtained from the filters are apparent magnitude values, which is a measure of the brightness as seen by the observer. Therefore to allow for comparison of magnitudes then have to be converted into absolute magnitudes (equation 12), where the absolute magnitude is a the apparent magnitude of the object if it were placed at a distance of 10 parsecs from the observer with no extinction due to dust or gas. M=m-5((〖log〗_10 D_L )-1) (12) Where M is the absolute magnitude, m is the apparent magnitude from the filter and DL is the luminosity distance. The absolute magnitude values are very useful, as they can be used to look for any patterns in SNe Ia as has been shown in previous studies. The R magnitude is particular important due to it relationship with galaxy age as well as metallicity, G-R colour and R-Z colour. Smaller magnitudes indicate older galaxies, because a smaller absolute magnitude actually implies the galaxy emits more light at that wavelength. Particular focus is paid to G-R colour and metallicity. G-R colour is the difference between the absolute magnitude in the Green filter and the Red filter and provides an indication of how red a galaxy is. The metallicity quantifies the amount of heavy elements present in the galaxy; these are elements that are not hydrogen or helium. The metallicity provides a good indication of galaxy age, with higher metallicity contents expected in older galaxies as discussed in section