The Size of Accretion Disks from Self-consistent X-Ray Spectra and UV/Optical/NIR Photometry Fitting: Applications to ASASSN–14li and HLX–1
We implement a standard thin disk model with the outer disk radius ( R _out ) as a free parameter, integrating it into a standard X-ray fitting package to enable self-consistent and simultaneous fitting of X-ray spectra and Ultraviolet (UV), Optical, and Near-infrared (NIR) photometry. We apply the...
Saved in:
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
|
| Series: | The Astrophysical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4357/ad990a |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | We implement a standard thin disk model with the outer disk radius ( R _out ) as a free parameter, integrating it into a standard X-ray fitting package to enable self-consistent and simultaneous fitting of X-ray spectra and Ultraviolet (UV), Optical, and Near-infrared (NIR) photometry. We apply the model to the late-time data (Δ t ≈ 350–1300 days) of the tidal disruption event (TDE) ASASSN–14li. We show that at these late times, the multiwavelength emission of the source can be fully described by a bare compact accretion disk. We obtain a black hole mass ( M _BH ) of ${7}_{-2}^{+3}\times 1{0}^{6}{M}_{\odot }$ , consistent with host-galaxy scaling relations, and an R _out of 45 ± 13 R _g , consistent with the circularization radius, with possible expansion at the latest epoch. We discuss how simplistic models, such as a single-temperature blackbody fitted to either X-ray spectra or UV/optical photometry, lead to erroneous interpretations of the scale/energetics of TDE emission. We also apply the model to the soft/high state of the intermediate-mass black hole candidate HLX–1. The model fits the full spectral energy distribution (from X-rays to NIR) without needing an additional stellar population component. We investigate how relativistic effects improve our results by implementing a version of the model with full ray tracing calculations in the Kerr metric. For HLX–1, we find ${M}_{{\rm{BH}}}={4}_{-1}^{+3}\times 1{0}^{4}{M}_{\odot }$ and R _out ≈ few × 10 ^3 R _g , in agreement with previous findings. The relativistic model can constrain the inclination ( i ) of HLX–1 to be 10° ≤ i ≤70°. |
|---|---|
| ISSN: | 1538-4357 |