Testing the role of environmental effects on the initial mass function
  of low-mass stars
  In the star formation process, the vital impact of environmental factors such
as feedback from massive stars and stellar density on the form of the initial
mass function (IMF) at low-mass end is yet to be understood. Hence a
systematic, highly sensitive observational analysis of a sample of regions
under diverse environmental conditions is essential. We analyse the IMF of
eight young clusters ($<$5 Myr), namely IC1848-West, IC1848-East, NGC 1893, NGC
2244, NGC 2362, NGC 6611, Stock 8 and Cygnus OB2, which are located at the
Galactocentric distance ($R_g$) range $\sim$6-12 kpc along with nearby cluster
IC348 using deep near-IR photometry and Gaia DR2. These clusters are embedded
in massive stellar environments of radiation strength $log(L_{FUV}/L_{\odot})$
$\sim$2.6 to 6.8, $log(L_{EUV})$ $\sim$42.2 to 50.85 photons/s, with stellar
density in the range of $\sim$170 - 1220 stars/pc$^2$. After structural
analysis and field decontamination we obtain an unbiased, uniformly sensitive
sample of pre-main-sequence members of the clusters down to brown-dwarf regime.
The lognormal fit to the IMF of nine clusters gives the mean characteristic
mass ($m_c$) and $\sigma$ of 0.32$\pm$0.02 $M_\odot$ and 0.47$\pm$0.02,
respectively. We compare the IMF with that of low- and high-mass clusters
across the Milky Way. We also check for any systematic variation with respect
to the radiation field strength, stellar density as well with $R_g$. We
conclude that there is no strong evidence for environmental effect in the
underlying form of the IMF of these clusters.
