Dice Question Streamline Icon: https://streamlinehq.com

Identifying true host-galaxy structural parameters under PSF uncertainties

Determine the true values of AGN host-galaxy structural parameters derived from JWST/NIRCam image decompositions—specifically the Sérsic index, effective radius, and host-to-total flux ratio—in the presence of PSF reconstruction uncertainties that can bias these estimates.

Information Square Streamline Icon: https://streamlinehq.com

Background

The paper compares multiple PSF reconstruction strategies (x2-based stacking and PSFEx modeling) and finds generally consistent decompositions but acknowledges method-dependent biases, particularly at high Sérsic indices and in long-wavelength bands where PSF width differences are more pronounced.

Because only estimated values are available and the true PSF is uncertain, the exact structural parameters cannot be pinned down uniquely with the current methods and data.

References

Nonetheless, these discussions are based on the comparisons between estimated values, and here, we cannot definitively determine the true exact value.

— The $M_{\rm BH}-M_*$ relation up to $z\sim2$ through decomposition of COSMOS-Web NIRCam images (2401.13742 - Tanaka et al., 24 Jan 2024) in Section 4.2 (Impact of different PSF models)