Context

• Following up on several of the open questions from the meeting yesterday. The goal is to be able to pass off a (conservative) version of the catalog to the Vanderbilt folks on Friday.
• The main focus here is understanding the lowest and high mass sources, trying to better understand what these objects are and if simple mass cuts work on removing them.

Diagnostics

W1 vs. W1-W2

• One thing we wanted to investigate -- we wanted to see how correlated the W1 magntiude is with the W1-W2 color, so I have a few visualizations of this. The punchline is that there doesn't appear to be a very strong trend between W1 and the color, either observed or absolute magnitude.

W1 vs. Color
images/260114/w1_versus_color.png

Comparison of dynamical Mbh vs W1-W2 Mbh without scatter

• Up to now, I had been drawing Mbh from Mstellar using the intrinsic scatter quoted in MM13, but it's probably most fair to simply use the mean relation for the comparisons we have been doing. I've reprocessed the comparison with Remco and with MM13, and here are those results:
  • Note that I've removed all the "upper limit" points from the Remco comparison:

Case	1-to-1	Residuals
MM13	[images/260114/comparison_plot_upperlimits_MM13_no_scatter.png]]](/JacobPilawa/TriaxSchwarzschild_wiki_6/wiki/[[images/260114/resid_mm13_no_scatter.png)
vdb16	[images/260114/comparison_plot_upperlimits_vdb16_no_scatter.png]]](/JacobPilawa/TriaxSchwarzschild_wiki_6/wiki/[[images/260114/resid_vdb16_no_scatter_no_upper_lim.png)

Highest and Lowest Mass Galaxies

Lowest Mass galaxies

• I think the most major issue we wanted to make sense of were the galaxies with very large or very small inferred stellar masses (say, below 10^7 Msun and above 10^12 Msun).
• First, here's a histogram of the stellar masses for the ~19.6 million galaxies in the catalog:
  • There are 4438 sources with Mstar < 10^7 Msun (about 0.2% of sources)
  • There are 343240 sources with Mstar > 10^12 Msun (about 1.75% of sources)

Stellar Mass Histogram
images/260114/mstar_dist.png

• I then split these into three groups, with the goal of seeing whether grouping by mass reveals any trends with color or redshift.
  • Msun < 1e7
  • Msun > 1e7 & Msun < 1e12
  • Msun > 1e12 Msun
• I then plotted the distributions of some of the relevant quantities for these groups:

Mass Group Distributions
images/260114/distributions_split.png

• Immediately the redshift distribution for the lowest mass galaxies stood out to me, so I plotted this a bit more clearly:
  • It seems like the lowest mass galaxies are preferentially at z<0.01 or so, whereas the higher mass galaxies have very few galaxies in this region. More specifically:
    • $\log(M_\star) < 7$: 4438 galaxies with zPhoto_Corr < 0.011
    • $7 \leq \log(M_\star) \leq 12$: 10154 galaxies with zPhoto_Corr < 0.011
    • $\log(M_\star) > 12$: 0 galaxies with zPhoto_Corr < 0.011

|Zoomed redshift distribtuion| |---|---| |diff. x-axis ranges |images/260114/zdist1.png| |identical x-axis ranges|images/260114/zdist2.png| |identical ranges, colored by sample|images/260114/zdist3.png|

• So at least for the lowest mass galaxies, we're probably fine to simply impose a lower bound of z=0.01 on the data,

Highest Mass Galaxies

• It also seems like we can explain most of the high mass galaxies with the redshift distributions too. To my eye, it seems like the most massive galaxies are preferentially at z>0.5 or so, which is also roughly the redshift range quoted as being "reliable" in the WSCOS catalog. More specifically:

  • $\log(M_\star) < 7$: 0 galaxies with zPhoto_Corr > 0.5
  • $7 \leq \log(M_\star) \leq 12$: 8 galaxies with zPhoto_Corr > 0.5
  • $\log(M_\star) > 12$: 2073 galaxies with zPhoto_Corr > 0.5

• Here are some similar histograms for the high mass galaxy case:

|Zoomed redshift distribtuion| |---|---| |identical x-axis ranges|images/260114/zdist2_highmass.png| |identical ranges, colored by sample|images/260114/zdist3_highmass.png|

• Likewise for the high mass galaxies, we can probably restrict the redshift to be z<0.5 to greatly clean up the high mass end of galaxies too.