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Near Infrared Camera and Multi-Object Spectrometer Instrument Handbook for Cycle 17 > Appendix B: Flux Units andLine Lists > B.4 Examples

B.4 Examples
1.
Given a source with a flux of 0.9mJy at 1350, convert this flux to erg s-1cm-2-1. From section 3, Table B.1, we see that the conversion constant β is 310–13 and the wavelength is 1350 = 0.135μm. Thus:
 
2.
Given a V magnitude of 15.6, and knowledge that V–K=2.5 in the UKIRT system, estimate the flux in Jy at K. Since V–K=2.5 we know that K=13.1. From Table B.2, the zero-point flux in the UKIRT system for K is 657Jy. Thus the 2.2μm flux is:
 
3.
Given a surface brightness of 21.1 magnitudes arcsec-2 at J, convert this into Jy arcsec-2. Taking the zero-point for the J band from Table B.2, we determine that the surface brightness is:
 
4.
Given a flux at 0.9μm of 2.310–7Jy, estimate the I magnitude. 2.310–7Jy is less than 2.310–1Jy by three powers of a hundred, or 15 magnitudes. From Table B.3 we see that 0.25Jy is equivalent to an I-band magnitude of 9.89. Thus 2.310–7 is roughly 15 magnitudes fainter than this, or of order:

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