The control sample has a redshift range of from 0.2 to 0.6 and a date range of from 2004-04-22 to 2005-01-31. The links for each field list the individual SNe Ia in both samples (control, full) and show a plot of the observations and their limiting mag values.
SNLS SN Ia Candidate Accounting: Tue Jul 26 09:21:24 2005
0.2 < specz < 0.6 : 25
SNIa/SNIa? D1 : 9
SNIa/SNIa? D2 : 4
SNIa/SNIa? D3 : 6
SNIa/SNIa? D4 : 6
The full sample (z sorted) (D1, D2, D3, D4) has the same redshift range, but goes from 2003-06-05 until 2005-05-18. I have weeded out SNe Ia that do not pass the detection criteria for the control sample to allow a comparison between samples. The sample is also broken down by year of observation below.
FULL SAMPLE :
0.2 < specz < 0.6 : 51 Y1 Y2
SNIa/SNIa? D1 : 15 6 9
SNIa/SNIa? D2 : 17 5 12
SNIa/SNIa? D3 : 8 8 0
SNIa/SNIa? D4 : 11 5 6
Potentially missed Type Ia SNe come from the sample with "SN" somewhere in the type and having a photz between 0.1 and 0.7. We use this redshift range because the photz's in the database were done with real-time analysis (RTA) photometry and could change with final photometry. The breakdown of the classifications relevant to our control sample are shown below:
SNLS SN Ia Candidate Accounting: Tue Jul 26 09:21:24 2005
0.1 < photz < 0.7 : 137
Date range : 2004-04-22 to 2005-01-31
specz + ID : 47 grp6 These are IDd and accounted for
specz + SN : 3 grp1 These could be missed Ias
specz + SN? : 3 grp1 So could these
specz + SNI : 2 grp1 And so could these
photz + SN? : 60 grp5 Let us look at these too
photz + SNII : 1 grp2 Check, but not likely
photz + SNII? : 1 grp2 Check, but not likely
photz + SN/AGN? : 16 grp4 Check, but not likely
photz + SN/var? : 4 grp3 Check, but not likely
photz + SN/PSFM? : 0 grp3 Check, but not likely
These SN candidates were classified originally with RTA photometry of the first few epochs. For this study, we use final photometry and the entire light curve. We assign an index, devloped by Andy Howell and called the "Howell Index" (HI), that quantifies the confidence that the candidate is a genuine Type Ia SN. The index runs from 0.0, meaning definitely NOT a SN Ia, to 5.0, meaning a definite SN Ia. I have added the index -2.0, which means that the object is out of range: either the redshift is outside the range of interest or the peak of the light curve is outside the time period of interest.
The HI for the potentially missed SN Ia's are given, with comments in the linked files below:
Here's how the current HI's break down for the 91 non-grp6 objects:
Now that we have final photometry for these objects, we can use a stricter redshift limit (z from 0.2 to 0.6) with the assumption that, in the mean, as many missed candidates are scattered out of this range as scattered in by the photz errors. This removes 4 of the HI 2-3 objects and leaves the following:
The Canadian SNLS was not searching in the gaps between chips until October of 2004. These objects were discovered by the French RTA. We must account for possible SN Type Ia's missed in the gaps during this time. The Canadian final photometry for these objects allows a photoz fit and HI consistent with those of the SN candidates above. The following is a list of the gap objects and their HI from final photometry:
In the gap only 1 SN candidate is a potentially missed Ia: 04D3fs.
Bottom line: Adding this 1 to the 9 above gives a total of 10 SN Candidates that could be missed Type Ia SNe in the range 0.2 < z < 0.6 and in the date range from 2004-04-22 to 2005-01-31. They are listed here:
If we assume 1/2 of these are real Ias and then use the extremes of all and none are real to define our limits we get the following completeness values for out control sample:
| Field | 1/2 Missed | Spec | Sample | % Complete |
|---|---|---|---|---|
| D1 | 2 | 9 | 11 +- 2 | 82 +18-13 |
| D2 | 0 | 4 | 4 +- 0 | 100 |
| D3 | 1.5 | 6 | 7.5 +- 1.5 | 80 +20-13 |
| D4 | 1.5 | 6 | 7.5 +- 1.5 | 80 +20-13 |
| ALL | 5 | 25 | 30 +- 5 | 83 +17-12 |
Last updated, 20 Oct 2005
Please send questions or comments to Don Neill at
neill@uvic.ca