Speakers
Description
The HAWC observatory detected ฆร-ray emission from the microquasar V4641 Sgr ($\gt$ 200 TeV) and revealed a $\sim$ 100 pc bubble, indicating PeV--scale particle acceleration; LHAASO subsequently extended the spectrum to ~0.8 PeV. In IR--mm data, we identify a millimeter clump $\sim$ 20$'$ from the microquasar, report its position and basic properties, and assess any spatial/kinematic association with V4641 Sgr.
The LHAASO observatory discovered J2108+5157 at ultra--high energies, and HAWC with subsequent observations measure significant 3--146~TeV emission, favor an extended morphology, and deliver a power-law spectral fit that further constraints and refines its PeVatron-candidate nature. In the absence of a confirmed counterpart, and indications of hadronic illumination of molecular/atomic gas, the source remains observationally enigmatic.
In this contribution we present pioneering APEX $^{12,13}$CO (J=2$\rightarrow$1) data for V4641 Sgr and new Nobeyama $^{12,13}$CO (J=1$\rightarrow$0) data for LHAASO~J2108+5157, combined with DRAO/HI4PI H\,I, to test hadronic scenarios via target--gas constraints and to propose counterparts toward LHAASO J2108+5157.
