The Cold Dust Content of the Nearby Galaxies IC 5325, NGC 7496, NGC
  7590, and NGC 7599
  Star-forming galaxies are rich reservoirs of dust, both warm and cold. But
the cold dust emission is faint alongside the relatively bright and ubiquitous
warm dust emission. Recently, evidence for a very cold dust component has also
been revealed via millimeter/submillimeter photometry of some galaxies. This
component, despite being the most massive of the three dust components in
star-forming galaxies, is by virtue of its very low temperature, faint and hard
to detect together with the relatively bright emission from warmer dust. Here
we analyze the dust content of a carefully selected sample of four galaxies
detected by IRAS, WISE, and SPT, whose spectral energy distributions (SEDs)
were modeled to constrain their potential cold dust content. Low-frequency
radio observations using the GMRT were carried out to segregate cold dust
emission from non-thermal emission in millimeter/submillimeter wavebands. We
also carried out AstroSat/UVIT observations for some galaxies to constrain
their SED at shorter wavelengths so as to enforce energy balance for the SED
modeling. We constructed their SEDs across a vast wavelength range (extending
from ultraviolet to radio frequencies) by assembling global photometry from
GALEX FUV+NUV, UVIT, Johnson BRI, 2MASS, WISE, IRAC, IRAS, AKARI, ISOPHOT,
Planck HFI, SPT, and GMRT. The SEDs were modeled with CIGALE to estimate their
basic properties, in particular to constrain the masses of their total and very
cold dust components. Although the galaxies' dust masses are dominated by
warmer dust, there are hints of very cold dust in two of the targets, NGC 7496
and NGC 7590.
