This document discusses building density maps of the local universe using red clump (RC) stars and galaxy distributions from the Dark Energy Survey (DES). It selects RC stars from the CasJobs database and projects their maps using different projections. It subtracts foreground stars using the Galaxia and Trilegal models to map the halo RC star distributions in the north and south. It also builds maps of galaxy distributions at z~1/3 from the DES PhotoZ catalog. The document reviews literature on searches for evidence of a supervoid near the Planck Cold Spot region using different galaxy surveys that have had limited sky coverage to make definitive conclusions.

1. Topics in Exploring the Local
Universe through Density Maps
Tiger Shi
Adviser: Dr. James Annis
DES Gravitational Wave Galaxy Catalog.

2. Overview:
● Building Maps of the Galactic Halo
– Selecting RC Stars from CasJobs
– Map Projections of RC Stars
– Halo RC Stars using Galaxia foreground subtraction:
● Northern RC Stars
● Southern RC Stars
– Halo RC Stars using Trilegal foreground subtraction
● Building maps of the z~1/3 galaxy distribution
– DES PhotoZ Catalog Maps

3. Selecting RC Stars from CasJobs
SDSS Skyserver
CasJobs Database
(http://skyserver.sdss.org/casjobs/)

4. Projecting the RC Stars 13<i<20
Plate Carree: Lambertian Equal Area:

5. Plotting SDSS North RC Star Residuals
30 kpc Bin:
60 kpc Bin:

6. Plotting SDSS South RC Star Residuals

7. Trilegal Model: RC Star Density

8. Trilegal Foreground Subtraction

9. DES RC Stars with Galaxia and Trilegal

10. Planck's Cold Spot: Literature
● Szapudi, et al., 2015:
– Found evidence suggesting the
existence of a supervoid
– WISE-2MASS IF Galaxy Catalogue
● Bremer, et al., 2010:
– Could not find evidence for supervoid
– Area of coverage was too small for the
conclusions to be believable
– VIMOS Spectrograph on the VLT
● Granett, et al., 2010:
– Also could not detect supervoid
– MegaCam Imaging
– “Due to the limited sky coverage of our [the] survey, we [Granett's team] cannot draw a
definite conclusion regarding the existence of a coherent supervoid structure.”
Szapudi, et al., 2015.

11. Galaxy Density Maps from Y1A1 and Y2Q1 with i<20

12. Plotting DES Data: Photo Z Check

13. Conclusion:
● Building Maps of the Galactic Halo
– Selecting RC Stars from CasJobs
– Map Projections of RC Stars
– Halo RC Stars using Galaxia foreground subtraction:
● Northern RC Stars
● Southern RC Stars
– Halo RC Stars using Trilegal foreground subtraction
● Building maps of the z~1/3 galaxy distribution
– DES PhotoZ Catalog Maps

14. Questions?
● Special Thanks to Dr James Annis and the DES team