Cosmic evolution early release science survey (CEERS): multiclassing galactic dwarf stars in the deep JWST/NIRCam
Academic Article
Overview
Research
Identity
Additional Document Info
Other
View All
Overview
abstract
ABSTRACTLow-mass (sub)stellar objects represent the low end of the initial mass function, the transition to free-floating planets and a prominent interloper population in the search for high-redshift galaxies. To what accuracy can photometry only classify these? JWST/NIRCam has several advantages over Hubble Space Telescope (HST)/WFC3 near-infrared (NIR): more filters, a greater wavelength range, and greater spatial resolution. Here, we present a catalogue of (sub)stellar dwarfs identified in the cosmic evolution early release science survey (CEERS). We identify 518 stellar objects down to mF200W28 using half-light radius, a full three magnitudes deeper than typical HST/WFC3 images. A k-means nearest neighbour (kNN) algorithm identifies and types these sources, using four HST/WFC3 and four NIRCam filters, trained on IRTF/spex spectra of nearby brown dwarfs. The kNN with four neighbours classifies well within two subtypes: e.g. M22, achieving 95percent precision and recall. In CEERS, we find 9 M82, 2 L62, 1 T42, and 15 T82. We compare the observed long wavelength NIRCam colours not used in the kNN to those expected for brown dwarf atmospheric models. The NIRCam F356WF444W and F410MF444W colours are redder by a magnitude for the type assigned by the kNN, hinting at a wider variety of atmospheres for these objects. We find a 300350pc scale height for M62 dwarfs plus a second structural component and a 150200pc scale height for T62 type dwarfs, consistent with literature values. A single M82 dwarf is spectroscopically confirmed at 4kpc distance.
