Talk:CG4 Fall Work
Blog for Milestones and Journaling Progress
Nov. 5, 2010 Team WI and Kevin
We have made some progress today. We learned to make color images of CG4 and SA101 using DS9. Viv commented on all the objects in the YSO Candidates for CG4. Kevin made color coded regions for all of the previously known YSOs, and YSO Candidates in both CG4 and SA101. Kevin got us started on making color images. Lyssa and Anna, Kevin, Mark, and Jen and Viv mastered making color images. Anna taught all of us a thing or two.
"How can I convert 2MASS magnitudes into Janskys?" 2MASS catalog and database magnitudes can be converted to flux densities (Janskys) using the following flux for zero-magnitude zero point conversion values:
Band Lambda (µm) Bandwidth (µm) Fnu - 0 mag (Jy) Flambda - 0 mag (W cm-2 µm-1)
J 1.235 ± 0.006 0.162 ± 0.001 1594 ± 27.8 3.129E-13 ± 5.464E-15
H 1.662 ± 0.009 0.251 ± 0.002 1024 ± 20.0 1.133E-13 ± 2.212E-15
Ks 2.159 ± 0.011 0.262 ± 0.002 666.7 ± 12.6 4.283E-14 ± 8.053E-16
From this website
http://www.ipac.caltech.edu/2mass/releases/allsky/faq.html [1]
IRAC 1 : 280.9 Jy
IRAC 2 : 179.7 Jy
IRAC 3 : 115.0 Jy
IRAC 4 : 64.13 Jy
MIPS 1 : 7.14 Jy
MIPS 2 : 0.775 Jy
MIPS 3 : 0.159 Jy
Therefore, in order to convert the uJy that apex returns into magnitudes, use the equation 2 above, substituting these so-called "zero-point fluxes" in for "Fvega." Note that the zero-point fluxes are in Janskys and the fluxes returned by APEX are in microJanskys. You can find the zeropoints for 2MASS magnitudes on the web as well:
J : 1594 Jy
H : 1024 Jy
K : 666.7 Jy
