Are Kronberger 80 and/or Kronberger 82 regions PeVatron candidates for LHAASO J2108+5157?
Journal article, 2025
High-energy gamma-rays have been detected in the region of LHAASO J2108+5157 by the Fermi-LAT, HAWC and LHAASO-KM2A observatories. Cygnus OB2 in Cygnus-X has been confirmed as the first strong stellar cluster PeVatron in our Galaxy. Thus, the star-forming regions Kronberger 80 and Kronberger 82, located in the field of LHAASO J2108+5157, are analyzed to evaluate their stellar population and potential as associated PeVatron candidates. A distance of 10 kpc is adopted for Kronberger 80, while $\sim$1.6 kpc is estimated for Kronberger 82. Based on stellar densities, we report that their cluster radii are ${2{<^>{\prime }_{.}}5}$ and ${2{<^>{\prime }_{.}}0}$, while infrared photometry reveals poor stellar content in massive O-type stars in both cases. From optical data, the estimations of cluster ages are 5-12.6 and $\lesssim$5 Myr, respectively. We conclude that, in contrast to the stellar content of Cygnus OB2, it is unlikely that Kronberger 80 and Kronberger 82 are PeVatrons associated with LHAASO J2108+5157. The presence of a PeVatron in this region remains a mystery, but we confirm that the two Kronberger regions are star-forming regions undergoing formation rather than evolution.
gamma rays: ISM
ISM: clouds
ISM: molecules
ISM: individual objects (LHAASO J2108+5157, Kronberger 80, Kronberger 82)
Author
Akash Gupta
University of Cologne
Eduardo de la Fuente
University of Tokyo
University of Guadalajara
Ram K. Yadav
National Astronomical Research Institute of Thailand
Alicia Porras
National Institute of Astrophysics, Optics and Electronics
Saurabh Sharma
Aryabhatta Research Institute of Observational Sciences
Sei Kato
University of Tokyo
Sorbonne University
Daniel Tafoya
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Miguel A. Trinidad
Universidad de Guanajuato
University of Guadalajara
Harold E. Viveros
Universidad de Guanajuato
Kazumasa Kawata
Sorbonne University
Hiromasa Suzuki
Japan Aerospace Exploration Agency (JAXA)
Munehiro Ohnishi
Sorbonne University
Ivan Toledano-Juarez
University of Guadalajara
Takashi Sako
Sorbonne University
Masato Takita
Sorbonne University
Publication of the Astronomical Society of Japan
0004-6264 (ISSN) 2053051x (eISSN)
Vol. 77 4 773-784Subject Categories (SSIF 2025)
Astronomy, Astrophysics, and Cosmology
DOI
10.1093/pasj/psaf046