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r35170 r35219 3 3 # DVO Documentation 4 4 5 ## Release Notes on 3pi.20120525 5 (up to [PS1 Data Release](/ippdata/index.php)) 6 6 7 This database contains PS1 3pi observations through 2012/01/21. The 8 ubercal zero points have been applied to all exposures included in 9 that analysis. The remaining exposures have been tied to the ubercal 10 system via relative photometry. The ubercal measurements are given 11 10x their poisson weight to ensure they drive the photometric 12 solution. 7 Below are links to documentation related to the distributed data 13 8 14 The database has been merged with the PS1 Synthetic photometry 15 database (based on 2MASS and USNO-B). For objects brighter than the 16 saturation limit, the Synthetic photometry has been used for the mean 17 magnitudes (these can be identified by having bit 0x04 raised in the 18 mean filter flags). Objects which used ubercal photometry have the 19 bit 0x08 raised in the mean filter flags. 9 * [Photometric Reference Ladder, Release 12.01 Notes](photladder.php) 10 * [Photometric Reference Ladder, Release 12.01 Paper (pdf)](photladder-1206.20121230.pdf) 20 11 21 This database has also been merged with the 2MASS, WISE, and 22 SuperCOSMOS databases. The following photcodes are used for those 23 external photometric sources: 12 * [PS1 Photometric System](http://svn.pan-starrs.ifa.hawaii.edu/trac/ipp/wiki/PS1_Photometric_System) 13 * [Tonry et al paper on the PS1 Photometric System](http://adsabs.harvard.edu/abs/2012ApJ...750...99T) 24 14 25 <table class="page"> 26 <tr><th> Source </th><th> Photcode </th></tr> 27 <tr><td> 2MASS_J </td><td> 2011 </td></tr> 28 <tr><td> 2MASS_H </td><td> 2012 </td></tr> 29 <tr><td> 2MASS_K </td><td> 2013 </td></tr> 30 <tr><td> WISE_W1 </td><td> 2014 </td></tr> 31 <tr><td> WISE_W2 </td><td> 2015 </td></tr> 32 <tr><td> WISE_W3 </td><td> 2016 </td></tr> 33 <tr><td> WISE_W4 </td><td> 2017 </td></tr> 34 <tr><td> SYNTH.g </td><td> 3001 </td></tr> 35 <tr><td> SYNTH.r </td><td> 3002 </td></tr> 36 <tr><td> SYNTH.i </td><td> 3003 </td></tr> 37 <tr><td> SYNTH.z </td><td> 3004 </td></tr> 38 <tr><td> SYNTH.y </td><td> 3005 </td></tr> 39 <tr><td> SCOS.103a.E </td><td> 1150 </td></tr> 40 <tr><td> SCOS.4414.OG590 </td><td> 1151 </td></tr> 41 <tr><td> SCOS.4415.OG590 </td><td> 1152 </td></tr> 42 <tr><td> SCOS.IIIaF.OG590 </td><td> 1153 </td></tr> 43 <tr><td> SCOS.IIIaF.RG610 </td><td> 1154 </td></tr> 44 <tr><td> SCOS.IIIaF.RG630 </td><td> 1155 </td></tr> 45 <tr><td> SCOS.IIIaJ.GG385 </td><td> 1156 </td></tr> 46 <tr><td> SCOS.IIIaJ.GG395 </td><td> 1157 </td></tr> 47 <tr><td> SCOS.IVN.RG715 </td><td> 1158 </td></tr> 48 <tr><td> SCOS.IVN.RG9 </td><td> 1159 </td></tr> 49 </table> 50 51 <img width=1000px src="relphot.20120528/sigma.i.ubercal.20120528.v0.png"><br> 52 Map of the mean per-star residual (inst mag brighter than -10) for 53 i-band (ubercal data only). 54 <br> 55 56 <img width=1000px src="relphot.20120528/sigma.g.ubercal.20120528.v0.png"><br> 57 Map of the mean per-star residual (inst mag brighter than -10) for 58 g-band (ubercal data only). 59 <br> 60 61 <h3>Comparison with 2MASS</h3> 62 63 The plots below compare the PS1 grizy photometry with 2MASS photometry 64 by examining the location of the color-color locus for early (< K0) 65 main sequence stars. 66 67 For each pixel (0.5 degree on a side), I select all objects with PS1 r 68 < 20 and detected JHK magnitudes, keeping only those with S/N in 69 the mean > 50 and standard deviations less than 0.05 magnitudes. I 70 then fit the stellar locus in g-r,r-i for the g-r range 0.2 to 1.0, 71 and keep only objects that fall within 0.05 of that (linear) stellar 72 locus fit.<br> 73 74 I then fit the stellar locus with a line in each of the color-color diagrams 75 g-i,i-J; g-i,i-H; g-i,i-K. I measure the mean i-J color expected from 76 the fit for stars with g-i = 0.5. The figures below show the maps of 77 the i-J, i-H, and i-K offsets as well as the J-H and H-K offsets at 78 g-i = 0.5. The center of these maps is RA,DEC = 0,0, (east is left, 79 north is up). The pixels are 0.5 degrees on a side.<br> 80 81 These maps show three main features. The Galactic Plane is quite 82 clear, and not surprising: this test is particularly sensitive to 83 reddening. <br> 84 85 Several large scale patches are also visible (eg, the black patch near 86 RA ~ 150 deg). Disappointingly, these correspond to areas without 87 good ubercal ties -- in other words, these are regions in which the 88 data were obtained in non-photometric conditions. This shows the 89 limitation of using relative photometry to tie across individual 90 exposures. If the exposures have an extinction gradient, the 91 correction far from the photometrically tied region can drift from the 92 correct value. The largest region at RA ~ 150 matches a section with 93 poor i-band photometry and has a depth of roughly 0.1 magnitudes in 94 i-J. Assuming this is completely due to i-band errors, this 95 corresponds to about 0.06 magnitudes of drift to the center of this 96 region. <br> 97 98 The third pattern is at a lower level of intensity: N-S strips with 99 roughly E-W bands. They are most noticable in K and H-K. These 100 appear to correspond well to the 2MASS scanning pattern, and have an 101 amplitude corresponding to about 0.02 - 0.04 magnitudes of offset in 102 K. <br> 103 104 <img width=1000px src="relphot.20120528/dJ.allsky.20120528.v3.png"><br> 105 Map of the i-J color at g-i = 0.5. 106 <br> 107 108 <img width=1000px src="relphot.20120528/dH.allsky.20120528.v3.png"><br> 109 Map of the i-H color at g-i = 0.5. 110 <br> 111 112 <img width=1000px src="relphot.20120528/dK.allsky.20120528.v3.png"><br> 113 Map of the i-K color at g-i = 0.5. 114 <br> 115 116 Combinations of the above maps can highlight any problems in 2MASS 117 which are driven by the color rather than the mean magnitudes. 118 119 <img width=1000px src="relphot.20120528/dJH.allsky.20120528.v3.png"><br> 120 Map of the J-H color at g-i = 0.5. 121 <br> 122 123 <img width=1000px src="relphot.20120528/dHK.allsky.20120528.v3.png"><br> 124 Map of the H-K color at g-i = 0.5. 125 <br> 15 * [Schlafly et al ubercal paper](http://adsabs.harvard.edu/abs/2012ApJ...756..158S)
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