galaxy color matching in catalogs
DESCRIPTION
Galaxy Color Matching in Catalogs. Bryce Kalmbach University of Washington. What are we doing?. Finding best fit model SEDs for galactic catalog objects Need SEDs to provide observational catalogs Link between cosmological simulations and working science groups. Matching Algorithm. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/1.jpg)
Galaxy Color Matchingin CatalogsBryce Kalmbach
University of Washington
![Page 2: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/2.jpg)
What are we doing?
• Finding best fit model SEDs for galactic catalog objects
• Need SEDs to provide observational catalogs
• Link between cosmological simulations and working science groups
![Page 3: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/3.jpg)
Matching Algorithm• Calculate colors for model SEDs we want to
match– Use tools in sims_photUtils
• Find best least-squares fit across all colors for each catalog object– See readGalfast in sims_photUtils for example
![Page 4: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/4.jpg)
Sample Matching Result
![Page 5: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/5.jpg)
Current SED Models• Bruzual and Charlot (2003) with Chabrier (2003) IMF
• 4 different Star Formation Histories:• Burst• Constant• Exp• Instant
• Age grid from 1.585 Myr to 12.5 Gyr
• Metallicity from .5% to 250% Z_Solar using Padova (1994) isochrones
![Page 6: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/6.jpg)
B & C Model Coverage
![Page 7: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/7.jpg)
B & C Model Coverage
![Page 8: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/8.jpg)
B & C Model Coverage
![Page 9: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/9.jpg)
Galacticus Catalog
• Currently working with galacticus catalogs– Developed by Andrew Benson (see Benson 2010)
• Does not seem to match well with B&C SEDs
![Page 10: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/10.jpg)
Comparing Galacticus
![Page 11: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/11.jpg)
Comparing Galacticus
![Page 12: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/12.jpg)
Comparing Galacticus
![Page 13: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/13.jpg)
Need Better Coverage
• Should we get new SEDs?– FSPS (Conroy, Gunn & White 2009)
![Page 14: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/14.jpg)
Comparing with FSPS
![Page 15: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/15.jpg)
Comparing with FSPS
![Page 16: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/16.jpg)
Comparing with FSPS
![Page 17: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/17.jpg)
Need Better Coverage
• Should we get new SEDs?– FSPS (Conroy, Gunn & White 2009)
• Refine the coverage of our grid?
![Page 18: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/18.jpg)
Changing Grid Coverage
![Page 19: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/19.jpg)
Current Issues
• Bluer catalog objects than can currently match to SEDs– Single Star Populations?
![Page 20: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/20.jpg)
Individual Stars 10Myr
(J. Dalcanton)
![Page 21: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/21.jpg)
Current Issues
• Bluer catalog objects than can currently match to SEDs– Single Star Populations?
• Need more statistics from galaxy catalog– Will be provided in next run
![Page 22: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/22.jpg)
Future Work
• PCA (Principal Component Analysis)– Determine axes of maximum variance and use
these as new basis vectors– Reduce Dimensionality• Storage Savings
![Page 23: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/23.jpg)
Capture Information in Few Components
![Page 24: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/24.jpg)
Capture Information in Few Components
![Page 25: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/25.jpg)
Capture Information in Few Components
![Page 26: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/26.jpg)
99.8% Information in 10 Principal Components…but…
![Page 27: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/27.jpg)
Now 99.99999%, unfortunately with 2x components, but good color match
![Page 28: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/28.jpg)
Future Work
• PCA (Principal Component Analysis)– Determine axes of maximum variance and use
these as new basis functions– Reduce Dimensionality• Storage Savings• Challenge: What is the minimum number of
components we can get the maximum amount of accuracy from?
![Page 29: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/29.jpg)
Future Work
• PCA (Principal Component Analysis)– Continuous coverage of sample space rather than
grid
![Page 30: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/30.jpg)
PCA will provide continuum
![Page 31: Galaxy Color Matching in Catalogs](https://reader035.vdocument.in/reader035/viewer/2022062314/56812a9b550346895d8e56b4/html5/thumbnails/31.jpg)
Future Work
• PCA (Principal Component Analysis)– Continuous coverage of sample space rather than
grid• Challenge: How do we sample to get the best set of
eigenspectra? • Challenge: How do we find the eigenvalues that
generate an SED that best matches the object color?
– Will need new methods that can combine linear combinations of eigenspectra