3d dust mapping with ps1
Gregory Green (Harvard/CfA)
goal
- 2D dust maps already exist
- Determine dust density throughout Galaxy in 3D
- Give reddening at any point on sky, at any distance
Method
Divide detected stars into ~6'x6' pixels.
Assume each pixel has a different line-of-sight dust column.
Method
Infer distance, reddening & stellar type for each star
Method
Probability density in distance & reddening for each star in pixel
Method
Find distance-reddening curves consistent with all stars
Method
Obtain many possible disance-reddening profiles in one pixel
Better Stellar Inferences
Line-of-sight dust informs stellar reddenings & distances.
Detection Density
- Require 4-band detection, including 2 bands in PS1
- Aperture - PSF magnitude cut in two PS1 bands
- 800 million stars
Total Detections
PS1 vs 2MASS
Bands Per Star
Processing
Results
Visualize dust from different positions in Galaxy & directions.
Local Dust
Zooming Out
Voxel Shape
High angular resolution, low radial resolution.
Touring the Galaxy
3π Footprint
Future Avenues
- More NIR data (WISE, UKIDSS GPS, GLIMPSE)
- Assume spatial correlation between lines of sight
- Incorporate proper motions, parallaxes
- Gaia, LSST should allow much improved 3D dust maps
3D Dust with PS1
By Gregory Green
3D Dust with PS1
I present a 3D dust map of the Milky Way, based on Pan-STARRS 1 photometry of over half a billion stars. Our 3D dust map covers the footprint of the 3pi survey, tracing dust out to a distance of several kiloparsecs and a depth of a few magnitudes of reddening in E(B-V). In each pixel in the map, we infer the distance and reddening of each star, and then determine the range of reddening versus distance profiles that are consistent with all the stars along the line of sight. The map has a typical angular resolution of 7', varying with the surface density of stars across the sky, and a distance resolution of about 25%. At large distances, our map agrees well with 2D maps of dust, such as Schlegel, Finkbeiner & Davis (1998) and the newer Planck dust maps. At intermediate distances, it reveals structure from fine filamentary scales up to gross features in the Galaxy. In addition to PS1 photometry, we use near-infrared photometry from 2MASS. This allows us to peer through deeper clouds, where PS1 optical photometry is heavily extinguished. In the future, we will be able to leverage new datasets, such as LSST and GAIA, to produce the next generation of 3D maps of our Galaxy.
