The Initial Mass Function Based on the Full-sky 20 pc Census of ∼3600 Stars and Brown Dwarfs

Copyright and License

© 2024. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

Acknowledgement

D.K., F.M., and C.G. acknowledge support from grant No. 80NSSC20K0452 awarded for proposal 18-2ADAP18-0175 under the NASA Astrophysics Data Analysis Program. Data presented here are based on observations obtained at the Hale Telescope, Palomar Observatory as part of a continuing collaboration between the California Institute of Technology, NASA/JPL, Yale University, and the National Astronomical Observatories of China. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. This research has made use of the Keck Observatory Archive (KOA), which is operated by the W. M. Keck Observatory and the NASA Exoplanet Science Institute (NExScI), under contract with the National Aeronautics and Space Administration. The first author would like to thank Patrick Shopbell at Caltech for resurrecting an Exabyte drive that successfully read raw CTIO data from 1997. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). He would also like to thank Mike Cushing for discussion of evolved star loci in the 20 pc color–magnitude diagrams.

One observation reported in this paper was obtained with the Southern African Large Telescope (SALT) under program 2021-2-SCI-027 (PI: Faherty). R.R. acknowledges support from grant RYC2021-030837-I funded by MCIN/AEI/ 10.13039/501100011033 and by "European Union NextGenerationEU/PRTR," and partial support by the AGAUR/Generalitat de Catalunya grant SGR-386/2021 and by the Spanish MINECO grant PID2020-117252GB-I00. E.G. acknowledges support from the Heising-Simons Foundation through a 51 Pegasi b Fellowship. This publication makes use of VOSA, developed under the Spanish Virtual Observatory (https://svo.cab.inta-csic.es) project funded by MCIN/AEI/10.13039/501100011033/ through grant PID2020-112949GB-I00. This research made use of the Montreal Open Clusters and Associations (MOCA) database, operated at the Montréal Planétarium (J. Gagné et al. 2024, in preparation). Backyard Worlds research was supported by NASA grant 2017-ADAP17-0067 and by the NSF under grants AST- 2007068, AST-2009177, and AST-2009136. J.V. acknowledges support from a Royal Society—Science Foundation Ireland University Research Fellowship (URF\1\221932). The authors would like to thank the Near-Earth Object Surveyor mission for covering the page charges for this paper through contract No. 80MSFC20C0043.

Facilities

WISE, Gaia, Spitzer (IRAC), Hale (WIRC, DBSP, TSpec), Keck:I (MOSFIRE, NIRES), IRTF (SpeX), Gemini:South (FLAMINGOS-2), Blanco (RCSPec, ARCoIRIS), NTT (SOFI), Magellan:Baade (FIRE), Shane (Kast), SALT (RSS), SOAR (OSIRIS), ARC (TSpec)

Software References

WiseView (Caselden et al. 2018), Spextool (Vacca et al. 2003; Cushing et al. 2004), MOPEX/APEX (Makovoz & Khan 2005; Makovoz & Marleau 2005), IRAF (Tody 1986, 1993), kastredux (A. J. Burgasser et al. 2024, in preparation), FIREHOSE/MASE (Bochanski et al. 2009), crowdsource (Schlafly et al. 2018)