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Size bias in galaxy surveys.
Fabian Schmidt1, Eduardo Rozo, Scott Dodelson
1Department of Astronomy and Astrophysics, The University of Chicago, Chicago, Illinois 60637-1433, USA.
Physical Review Letters
|October 2, 2009
Summary
Gravitational lensing can distort galaxy appearance, affecting survey catalogs. This study reveals that size bias, caused by lensing, can significantly impact galaxy statistics more than magnification bias in astronomical surveys.
Area of Science:
- Cosmology
- Astrophysics
- Galaxy Evolution
Background:
- Astronomical surveys select galaxies based on brightness and size.
- Gravitational lensing by foreground objects can alter the apparent brightness and size of distant galaxies.
Purpose of the Study:
- To investigate the impact of size bias on galaxy statistics in astronomical surveys.
- To understand how size bias interacts with magnification bias.
Main Methods:
- Simulations and analysis of galaxy catalog properties.
- Comparison of size bias effects versus magnification bias effects.
Main Results:
- Galaxies can be scattered across magnitude and size selection cuts due to gravitational lensing.
- Photometric galaxy samples are demonstrably more affected by size bias than magnification bias.
Conclusions:
- Size bias is a critical factor to consider when analyzing galaxy populations from surveys.
- Upcoming surveys must account for size bias to ensure accurate galaxy statistics and cosmological interpretations.
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