Hub-filament system in IRAS 05480+2545: young stellar cluster and 6.7
  GHz methanol maser
  To probe the star formation (SF) process, we present a multi-wavelength study
of IRAS 05480+2545 (hereafter I05480+2545). Analysis of Herschel data reveals a
massive clump (M_clump ~ 1875 Msun; peak N(H_2) ~ 4.8 x 10^{22} cm^{-2}; A_V ~
51 mag) containing the 6.7 GHz methanol maser and I05480+2545, which is also
depicted in a temperature range of 18-26 K. Several noticeable parsec-scale
filaments are detected in the Herschel 250 microns image and seem to be
radially directed to the massive clump. It resembles more of a "hub-filament"
system. Deeply embedded young stellar objects (YSOs) have been identified using
the 1-5 microns photometric data, and a significant fraction of YSOs and their
clustering are spatially found toward the massive clump, revealing the intense
SF activities. An infrared counterpart (IRc) of the maser is investigated in
the Spitzer 3.6-4.5 microns images. The IRc does not appear point-like source
and is most likely associated with the molecular outflow. Based on the 1.4 GHz
and Halpha continuum images, the ionized emission is absent toward the IRc,
indicating that the massive clump harbors an early phase of massive protostar
before the onset of an ultracompact H II region. Together, the I05480+2545 is
embedded in a very similar "hub-filament" system to those seen in Rosette
Molecular Cloud. The outcome of the present work indicates the role of
filaments in the formation of the massive star-forming clump and cluster of
YSOs, which might help channel material to the central hub configuration and
the clump/core.
