  This paper discusses infrared and millimetre-wavelength observations of a
Lyman-alpha blob discovered by Smith & Jarvis, a candidate for ionization by
the cold accretion scenario discussed in Fardal et al. and Dijkstra et al. We
have observed the counterpart galaxy at infrared wavelengths in deep
observations with the Spitzer Space Telescope using the IRAC 3.6, 4.5, 5.8 &
8.0 micron and MIPS 24 micron bands, as well as using the Max-Planck Millimeter
Bolometer Array at a wavelength of 1.2mm with the IRAM 30 metre telescope.
These observations probe the > 95kpc Lyman-alpha halo for the presence of
obscured AGN components or the presence of a violent period of star formation
invoked by other models of ionisation for these mysterious objects. 24 micron
observations suggest that an obscured AGN would be insufficiently luminous to
ionize the halo, and that the star formation rate within the halo may be as low
as <140 Msolar/yr depending on the model SED used. This is reinforced by our
observations at 1.2mm using MAMBO-2, which yield an upper limit of SFR <550
Msolar/yr from our non-detection to a 3 sigma flux limit of 0.86 mJy/beam.
Finding no evidence for either AGN or extensive star formation, we conclude
that this halo is ionised by a cold accretion process. We derive model SEDs for
the host galaxy, and use the Bruzual & Charlot and Maraston libraries to show
that the galaxy is well described by composite stellar populations of total
mass 3.42 +/- 0.13 x 10^11 Msolar or 4.35 +/- 0.16 x 10^11 Msolar depending on
the model SEDs used.
