April 12, 2019

April Updates

Status of the Project

Alex and I have settled on an ideal way to deal with the photometric redshift uncertainties on the RedMaPPer (RM) cluster data. The plan is to divide everything into fairly small redshift slices, corresponding to around 30 Mpc. For each slice, I'll make a projected number density map with the CMASS galaxies. (They have very low redshift uncertainties so they are essentially guaranteed to truly exist in that slice.) For every RM cluster, the catalog provides not only the calculated mean photo-z but also the probability distribution of photo-z. Therefore, for each redshift slice, I'll take every RedMaPPer cluster that has any probability of being in that slice (including those whose mean photo-z falls in another slice), and run these through COOP to get the orientation vector for each cluster. For example, if a cluster's photo-z probability extends over the z=.2 to .21 slice, the z=.21 to .22 slice, and the z=.22 to .23 slice, I will run this cluster with the orientation map for each of those bins and get 3 orientations out. Finally, I'll write my own stacking code which, for a single redshift slice of 30Mpc, stacks all the clusters that could possibly exist somewhere in that slice, orients them with the imported COOP orientations, and weights each cluster by the probability that it exists in that slice. (That probability is the area under the photo-z curve within that slice). With this method, we can do oriented stacks for reasonably small redshift slices and fully account for the uncertainties in the photometric redshifts of clusters.

However, re-writing and re-organizing my code to do this will be a long enough task that I probably won't be able to do it by the end of 1501. For now, I'll simply take slices of 100 comoving Mpc, make number density maps with all the CMASS galaxies in those slices, and assume that the RM clusters' photo-zs are accurate.

Numbers of Objects

I'm putting these numbers all down in one place so they're easy to find for future reference. For 100 Mpc slices, the amount of RedMaPPer (RM) clusters and CMASS galaxies in each slice which are also within the ACT region are:

432 to 532 Mpc: z = 0.100 to 0.124, 230 RM clusters, 132 CMASS galaxies

532 to 632 Mpc: z = 0.124 to 0.148, 199 RM clusters, 159 CMASS galaxies

632 to 732 Mpc: z = 0.148 to 0.173, 300 RM clusters, 250 CMASS galaxies

732 to 832 Mpc: z = 0.173 to 0.197, 320 RM clusters, 418 CMASS galaxies

832 to 932 Mpc: z = 0.197 to 0.222, 488 RM clusters, 543 CMASS galaxies

932 to 1032 Mpc: z = 0.222 to 0.248, 702 RM clusters, 749 CMASS galaxies

1032 to 1132 Mpc: z = 0.248 to 0.274, 725 RM clusters, 655 CMASS galaxies

1132 to 1232 Mpc: z = 0.274 to 0.300, 781 RM clusters, 784 CMASS galaxies

1232 to 1332 Mpc: z = 0.300 to 0.327, 726 RM clusters, 801 CMASS galaxies

1332 to 1432 Mpc: z = 0.327 to 0.354, 750 RM clusters, 915 CMASS galaxies

1432 to 1532 Mpc: z = 0.354 to 0.381, 1062 RM clusters, 1241 CMASS galaxies

1532 to 1632 Mpc: z = 0.381 to 0.409, 1058 RM clusters, 2299 CMASS galaxies

1632 to 1732 Mpc: z = 0.409 to 0.438, 1295 RM clusters, 6321 CMASS galaxies

1732 to 1832 Mpc: z = 0.438 to 0.467, 1327 RM clusters, 18987 CMASS galaxies

1832 to 1932 Mpc: z = 0.467 to 0.496, 1541 RM clusters, 30912 CMASS galaxies

1932 to 2032 Mpc: z = 0.496 to 0.526, 1548 RM clusters, 34299 CMASS galaxies

2032 to 2132 Mpc: z = 0.526 to 0.556, 1714 RM clusters, 33191 CMASS galaxies

2132 to 2232 Mpc: z = 0.556 to 0.588, 2136 RM clusters, 31107 CMASS galaxies

2232 to 2332 Mpc: z = 0.588 to 0.619, 1958 RM clusters, 25146 CMASS galaxies

2332 to 2432 Mpc: z = 0.619 to 0.652, 1314 RM clusters, 17373 CMASS galaxies

2432 to 2532 Mpc: z = 0.652 to 0.684, 478 RM clusters, 11308 CMASS galaxies

2532 to 2632 Mpc: z = 0.684 to 0.718, 115 RM clusters, 6677 CMASS galaxies

2632 to 2732 Mpc: z = 0.718 to 0.752, 28 RM clusters, 3498 CMASS galaxies

2732 to 2832 Mpc: z = 0.752 to 0.787, 2 RM clusters, 1579 CMASS galaxies

Example Plots of CMASS Sample

As you can see above, the most populated bin in the DES sample is at z~0.57. As an example, I've plotted the galaxies and clusters for this redshift slice.

Next, I make a Healpix Nside=2048 map where I put a '1' down in every pixel where there's a galaxy from the CMASS sample. Then I smooth this map with a 25' Gaussian beam. Here is the resulting smoothed number-density map for this redshift slice.