Testing the role of environmental effects on the initial mass function of low-mass stars. Issue 2 (1st May 2021)

• Record Type: Journal Article
• Authors: Damian, Belinda; Jose, Jessy; Samal, Manash R; Moraux, Estelle; Das, Swagat R; Patra, Sudeshna
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 504:Issue 2(2021)
• Page Start: 2557
• Page End: 2576
• Publication Date: 2021-05-01
• Subjects: stars: formation -- stars: low-mass -- stars: luminosity function, mass function -- stars: pre-main-sequence; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stab194
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: 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 the 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 IC 1848-West, IC 1848-East, NGC 1893, NGC 2244, NGC 2362, NGC 6611, Stock 8, and Cygnus OB2, which are located at the Galactocentric distance ( R g ) range ∼6–12 kpc along with the nearby cluster IC 348 using deep near-IR photometry and Gaia DR2. These clusters are embedded in massive stellar environments of radiation strength $\log(L_\mathrm{FUV}/\mathrm{L}_{\odot })\, \sim 2.6$ –6.8, $\log(L_\mathrm{EUV})\, \sim$ 42.2–50.85 photon s −1, with stellar density in the range of ∼170–1220 star 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 the brown-dwarf regime. The lognormal fit to the IMF of nine clusters gives the mean characteristic mass ( m c ) and σ of 0.32 ± 0.02 M⊙ and 0.47 ± 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 and the stellar density as well with R g . We conclude that there is no strong evidence for an environmental effect in the underlying form of the IMF of these clusters.