Figure 1 : Photometry of SN 2016gkg at discovery.

From: A surge of light at the birth of a supernova

Figure 1

The data show a 5σ detection limit (red arrow) and a sharp rise (points) starting less than 1 h after discovery. The inset images display a combination of the first series of 40 images (left) and a combination of the last series of 21 images (right). Photometry is shown for individual images (grey squares), combinations of 5 or 6 images (blue diamonds) and combinations of 17–21 images (red triangles). The dashed line is a linear fit to the blue diamonds, with a slope of 43 ± 6 mag d−1. Error bars are 1σ. Photometry from combined images reveals hints of structure around the linear fit, although its statistical significance is low (the reduced χ2 of the linear fit is 0.85).