Welcome to Reltrans’s documentation!

Welcome to the Reltrans documentation!

Reltrans is a publicly available, semi-analytical model for X-ray reverberation mapping of accreting black holes in both AGN and X-ray binaries. It can be used to compute both time-averaged spectra and energy-dependent, Fourier domain cross spectra. In order to perform relativistic ray-tracing, Reltrans assumes the lamp-post model for the coronal geoemtry, with some potential tweaks depending on the model flavour. For example, it is possible to include a second lamp-post self consistently, or to modify the angular dependence of the source emissivity.

Features

Reltrans used the YNOGK code to perform ray-tracing and calculate both energy shifts and light travel times, and then convolves the resulting kernel with the Xillver rest-frame reflection spectrum model.

The model accounts for multiple sources of lags self-consistently. Light-travel time lags from the corona to the disk are included naturally from the relativistic ray-tracing. Continuum lags driven by the variability of the corona are implemented through a pivoting power-law. Finally, the model accounts self-consistently for lags driven by changes in the reflection spectrum, which themselves are driven by variability in the power-law; in particular, the model computes the ionization changes in the disk due to changes in the corona luminosity, and the changes in the reflection spectrum due to the changes in the coronal photon index.

Reltrans is designed to be compatible with Xspec. If users are computing a time-averaged spectrum, it is then convolved with the instrument response identically to any other additive model in the software. If users are calculating a cross spectrum instead, then the convolution with the instrument response is handled internally by the model.

Reporting issues

If you find any issues with the code, we encourage you to contact the developers by opening an issue on the Github issues page.

Documentation contents

• Installation and setup instructions
• Reltrans model flavours

Citing Reltrans

If you use Reltrans in your research, we ask that you please cite the following papers:

• Ingram et al., 2019 MNRAS, 488, 324 [DOI] [ADS] [Copy BibTeX to clipboard]
• Mastroserio et al., 2021 MNRAS, 507, 55M [DOI] [ADS] [Copy BibTeX to clipboard]

Additionally, if you use the RTDist flavour we ask that you also cite:

• Ingram et al., 2022 MNRAS, 509, 619 [DOI] [ADS] [Copy BibTeX to clipboard]

Finally, if you use the double lamp post flavour, we ask that you also cite:

• Lucchini et al., 2023 ApJ, 951, 19 [DOI] [ADS] [Copy BibTeX to clipboard]