P425 finding chart, along with some field stars. The SN is in the second galaxy left of field star 1 (which is a rather small galaxy).

Spitzer image. We will be getting the reference images in the summer of 2006. We will need to do a subtraction.

Forced photometry from the 2005/2006 observing season.

Here is a preliminary P425 light curve, using templates from 2004 Nov 12 UT. Mag 25 = 1.00 flux units. The light curve templates are just rough eyeball estimates using the Goldhaber B-band template and the Knop V-band template. From Saurabh's thesis dm15 of 0.82 gives a B-band stretch factor of 1.098 and a V-band stretch factor of 1.112. I stretched the time axis by that amount and also by (1+z). I took the observed R-band peak to be Julian Date 2,453,701.

And here are the P425 light curves using templates made from an average of three nights from 2004 (Nov 12, Nov 16, and Dec 05). The resulting errors are smaller, since there is less noise in the templates. And the I-band peak is now about 9 flux units, compared to 11 flux units previously. The R-band template to guide the eye is the same in the two graphs, but the second I-band template (red dashed line) has the Y-axis scaled 9/11 of the I-band template in the first graph.

We should contemplate how we want to do our "final" analysis. There is certainly an advantage using deep(er) master templates from multiple, sharp images. Perhaps all this comes out in the wash with the N*(N-1)/2 method.

P534 finding chart and some of the nearby field stars.

Preliminary P534 light curve, based on CTIO 4-m imagery (dots) and one night of Gemini imagery (squares). The Gemini imagery was obtained on 2005 Jan 09 UT in the Sloan r and i filters, and the resultant fluxes were converted to the CTIO 4-m natural-system R and I fluxes. Here I used templates made from an average of 3 images obtained on 2004 Nov 16, Dec 09, and Dec 13 UT. I needed narrower light curve templates and used dm15 = 1.2 (stretch factors of 0.912 for B, 0.944 for V, plus the factor of 1+z. The redshift of this one is supposed to be 33 percent larger than P425, but notice that the R-band flux is comparable to that of P425, and possibly even slightly brighter. If the redshifts are indeed correct, this means that P425 must be reddened/dimmed in its little host.

We also obtained SOAR imagery on January 4, 8, 10, 12, and 17 UT (JD 2453739.7 through 2453752.6), but the sky levels were very, very high, drowning out the SN on many occasions. The upward-pointing triangles are from imagery of Jan 17 UT. The waning moon was 93 percent full that night, but the first R-band image was obtained with minimal moonlight, as the measured sky brightness was R = 20.89 mag per square arc second (which is about nominal for northern Chilean mountain sites without moonlight).

Go back to Kevin Krisciunas home page by clicking here.