Skip to main content
SearchLoginLogin or Signup

X-Ray Examination of Gravitationally Lensed Hyper-luminous Infrared Galaxies at z > 2

Presentation #104.02 in the session ISM/Galaxies - Poster Session.

Published onMay 03, 2024
X-Ray Examination of Gravitationally Lensed Hyper-luminous Infrared Galaxies at z > 2

Measuring the X-ray luminosity (Lx) of High Mass X-Ray Binaries (HMXBs) has been proposed as a method to trace the Star Formation Rate (SFR) of a galaxy. Although the Lx - SFR relation has been observed in local sources at z = 0 - 1.3, previous X-ray observations of three gravitationally lensed Hyper-luminous infrared galaxies (HyLIRGs) at z < 2.0 suggest that the X-ray luminosity may exceed the expected amount based on local calibrations by a factor ~3 based on spectral analysis. Two of the three sources exhibit hard X-ray spectra indicating the presence of AGNs despite all three sources showing no evidence of AGNs based on previously observed datasets (e.g. VLA, ALMA, SMA, HST, etc.). The centroid of the XMM images appears to have an offset of 6.6′′ from the HMXB emission expected from SFR tracers (e.g SMA CO continuum). This centroid does not appear to show evidence for CO emission or dust continuum based on the multi-wavelength data. Therefore, the separation may suggest that the AGN is located ~50 kpc from the HyLIRG. However, the redshift of the AGN still needs to be spectroscopically confirmed. Nevertheless, spatial decomposition of the X-ray images allowed to individually model the HMXB and AGN emission due to the offset. The 2-D spatial analysis appears to show distinct regions that emit high amounts of HMXB X-ray emission. This appears to the contradict the expectation of observing an evenly distributed HMXB population of these extremely SF galaxies. This excess in Lx provides evidence that the Lx - SFR relation may not be linear and may also depend on other mechanisms such as dynamical HMXB production in dense clusters which may result in high X-ray emission from clusters. Our results, ultimately provide insight into HMXB populations in HyLIRGs and present a method of identifying previously undetected AGNs in high redshift sources.

No comments here