Dereddening of WISE+2MASS data

[vrinda mukund]

Hello friends,

I was trying to plot the color-color diagram of a particular open cluster using WISE+2MASS data. You can get more details of the diagram from the following paper that i am attaching.[Koenig et.al - Wide Field Infrared Survey Explorer Observations of the evolution of the massive star forming regions-Appendix section -page 22- under the tittle Using 2mass data]. There it is written that we need to do the dereddening for plotting the CCD. And it is written like they have used the extinction law mentioned in Flaherty et al(2009) paper . But i can't understand the law that they have mentioned. Can somebody please help me with a simple explanation?? Pleaseeeeeeeeee...iam stucked up with my work

 

[lippyka]

. The paper that Flaherty et al (2009) wrote is focused on extinction laws in the mid-infrared and near-infrared. The extinction law is essentially a formula that describes the amount of light that is blocked out by dust and other particles. The Flaherty et al (2009) paper uses a power-law form to describe the extinction law. Specifically, they look at the relationship between the amount of extinction and the wavelength of light. The power-law form is A = C·λ^β, where A is the extinction, C is a coefficient, λ is the wavelength, and β is the power-law index. In their paper, Flaherty et al (2009) found that the power-law index was β = 1.75. This means that the extinction increases as the wavelength increases. So, when plotting the color-color diagram for your star cluster, you should use this power-law form with a power-law index of β = 1.75 to calculate the extinction for each point on the graph.