An HST Study of the Substellar Population of NGC 2024
Artikel i vetenskaplig tidskrift, 2024

We performed an HST/WFC3-IR imaging survey of the young stellar cluster NGC 2024 in three filters probing the 1.4 mu m H2O absorption feature, characteristic of the population of low-mass and substellar-mass objects down to a few Jupiter masses. We detect 812 point sources, 550 of them in all three filters with signal-to-noise ratio greater than 5. Using a distance-independent two-color diagram, we determine extinction values as high as A V similar or equal to 40. We also find that the change of effective wavelengths in our filters results in higher A V values as the reddening increases. Reconstructing a dereddened color-magnitude diagram, we derive a luminosity histogram both for the full sample of candidate cluster members and for an extinction-limited subsample containing the 50% of sources with A V less than or similar to 15. Assuming a standard extinction law like Cardelli et al. with a nominal R V = 3.1, we produce a luminosity function in good agreement with the one resulting from a Salpeter-like initial mass function for a 1 Myr isochrone. There is some evidence of an excess of luminous stars in the most embedded region. We posit that the correlation may be due to those sources being younger, and therefore overluminous, than the more evolved and less extincted cluster's stars. We compare our classification scheme based on the depth of the 1.4 mu m photometric feature with the results from the spectroscopic survey of Levine et al., and we report a few peculiar sources and morphological features typical of the rich phenomenology commonly encountered in young star-forming regions.

Författare

Massimo Robberto

Space Telescope Science Institute (STScI)

Johns Hopkins University

Mario Gennaro

Johns Hopkins University

Space Telescope Science Institute (STScI)

Nicola Da Rio

University of Virginia

Giovanni Maria Strampelli

Space Telescope Science Institute (STScI)

Universidad de la Laguna

Johns Hopkins University

Leonardo Ubeda

Space Telescope Science Institute (STScI)

Elena Sabbi

Space Telescope Science Institute (STScI)

Dana Koeppe

Johns Hopkins University

Jonathan Tan

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik

University of Virginia

David R. Soderblom

Space Telescope Science Institute (STScI)

Astrophysical Journal

0004-637X (ISSN) 1538-4357 (eISSN)

Vol. 960 1 49

Ämneskategorier

Astronomi, astrofysik och kosmologi

DOI

10.3847/1538-4357/ad0785

Mer information

Senast uppdaterat

2024-01-09