Discovery of Luminous Star Formation in PMN1452-5910/IRAS14482-5857: the
  Pterodactyl Nebula
  We present sensitive 1-3 GHz ATCA radio continuum observations of the
hitherto unresolved star forming region known as either IRAS14482-5857 or
PMN1452-5910. At radio continuum frequencies, this source is characterised by a
"filled-bubble" structure reminiscent of a classical HII region, dominated by
three point sources, and surrounded by low-surface-brightness emission out to
the $3'\times4'$ source extent observed at other frequencies in the literature.
The infrared emission corresponds well to the radio emission, with polycyclic
aromatic hydrocarbon emission surrounding regions of hot dust towards the radio
bubbles. A bright 4.5 $\mu$m point source is seen towards the centre of the
radio source, suggesting a young stellar object. There is also a linear,
outflow-like structure radiating brightly at 8 and 24 $\mu$m towards the
brightest peak of the radio continuum. In order to estimate the distance to
this source, we have used Mopra Southern Galactic Plane CO Survey
$^{12}$CO(1-0) and $^{13}$CO(1-0) molecular line emission data.
Integrated-intensity, velocity at peak intensity and line-fitting of the
spectra all point towards the peak centred at $v_{LSR}$=-1.1 km/s being
connected to this cloud. This infers a distance to this cloud of ~12.7 kpc.
Assuming this distance, we estimate a column density and mass towards
IRAS14482-5857 of ~$1.5\times10^{21}$ cm$^{-2}$ and $2\times10^4$ $M_\odot$,
implying that this source is a site of massive star formation. Reinforcing this
conclusion, our broadband spectral fitting infers dust temperatures of 19 and
110K, emission measures for the sub-pc radio point-source of emission measure
$EM\sim10^{6-7}$ pc cm$^{-6}$, electron densities of $n_e\sim10^3$ cm$^{-3}$
and photon ionisation rates of $N_{Ly}~10^{46-48}$ s$^{-1}$. The evidence
strongly suggests that IRAS14482-5857 is a distant, and hence intense site of
massive star-formation.
