3pi DVO Database Release 2012.06.06

(Up to the IPP for PS1)

• see ​http://dvodist.ipp.ifa.hawaii.edu/3pi.20120606 for data access (PS1SC members only)

The following tables and images explore the number of real and false detections in the 3pi database as a function of filter, magnitude, and position on the sky.

The table below lists the total number of GPC1 detections in each filter (all detections) as well as the number of GPC1 detections per filter associated with objects with more than 2 measurements (highly likely to be a real astrophysical object). Below are images showing the distribution of these values on the sky. The mean false fraction is the value (Nall - Ngood) / Ngood, while the median false fraction is the median of the per-pixel values (1 pixel is 10 arcmin x 10 arcmin).

filter	good detections	all detections	mean false frac	median false fraction
g	3.761962e+09	4.589117e+09	0.180	0.491
r	4.865315e+09	5.539615e+09	0.122	0.277
i	6.311162e+09	7.113843e+09	0.113	0.240
z	6.767039e+09	7.558130e+09	0.105	0.219
y	4.889023e+09	5.473861e+09	0.107	0.265

Some totals:

• Nall detections = 3.27e+10
• Ngood detections = 2.659450e+10
• mean false fraction = 13.8%
• Nall objects = 2.23e+09
• Ngood objects = 1.49e+09
• Nfalse objects = 7.4e+08
• mean false objects = 49.7%

Object and Detection Counts across the 3pi region

The following images show the density of objects (not detections) as distributed across the sky, with i band magnitude limits as from 16.0 to 23.5 (as given in the left-hand column).

i mag limit	log(objects per square degree) (dark : 2.0, light: 6.0)
16.0
16.5
17.0
17.5
18.0
18.5
19.0
19.5
20.0
20.5
21.0
21.5
22.0
22.5
23.0
23.5

The following images show the logarithm (base 10) of the density of 'good' GPC1 detections as distributed across the sky for each of the five filters grizy.

filter	log(good measurements per square degree) (dark : 2.5, light : 7.0)
g
r
i
z
y

The following images show the logarithm (base 10) of the density of all GPC1 detections as distributed across the sky for each of the five filters grizy.

filter	log(good measurements per square degree) (dark : 2.5, light : 7.0)
g
r
i
z
y

The following images show the false positive fraction [(Nall - Ngood) / Ngood] as a function of position.

filter	false fraction (dark : -0.02, light : 1.02)
g
r
i
z
y