  I calculate the spectral energy distributions (SEDs) of accreting
circumplanetary disks using atmospheric radiative transfer models.
Circumplanetary disks only accreting at $10^{-10} M_{\odot} yr^{-1}$ around a 1
M$_{J}$ planet can be brighter than the planet itself. A moderately accreting
circumplanetary disk ($\dot{M}\sim 10^{-8}M_{\odot} yr^{-1}$; enough to form a
10 M$_{J}$ planet within 1 Myr) around a 1 M$_{J}$ planet has a maximum
temperature of $\sim$2000 K, and at near-infrared wavelengths ($J$, $H$, $K$
bands), this disk is as bright as a late M-type brown dwarf or a 10 M$_{J}$
planet with a "hot start". To use direct imaging to find the accretion disks
around low mass planets (e.g., 1 M$_{J}$) and distinguish them from brown
dwarfs or hot high mass planets, it is crucial to obtain photometry at
mid-infrared bands ($L'$, $M$, $N$ bands) because the emission from
circumplanetary disks falls off more slowly towards longer wavelengths than
those of brown dwarfs or planets. If young planets have strong magnetic fields
($\gtrsim$100 G), fields may truncate slowly accreting circumplanetary disks
($\dot{M}\lesssim10^{-9} M_{\odot} yr^{-1}$) and lead to magnetospheric
accretion, which can provide additional accretion signatures, such as
UV/optical excess from the accretion shock and line emission.
