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Early emission characterization of TDE2025aarm

Andrea Simongini, Maria Kherlakian, Alicia López-Oramas, Josefa Becerra

Abstract

In this Letter, we present early emission data analysis of the tidal disruption event TDE2025aarm, including optical, UV and X-ray data. At a redshift of z = 0.01368, TDE2025aarm is the second closest TDE ever discovered, offering an unprecedented opportunity to study such phenomena in great details. We observed TDE2025aarm in optical with the Liverpool Telescope for a total of three epochs, and complemented our dataset with ancillary spectroscopic and photometric data. The early optical spectra are characterized by a blue-continuum and helium, hydrogen and possibly Bowen lines typical of H+He events. The optical light curves peak at M_g ~ -18.63 mag and are well described by fallback of a M_star ~ 0.16 M_sun star onto a M_BH ~ 2x10^{7} M_sun black hole. We report Swift-XRT detection in the 0.3-10 keV range, with a total flux of F_X ~ 1.42x10^{-14} erg s-1 cm-2, fitted by a black-body with kT ~ 0.39 keV. This makes TDE2025aarm a new event among optical/UV bright TDEs detected in soft X-rays. Our analysis suggests that the early emission from TDE2025aarm is powered by circularization shocks, and that the delayed accretion scenario best describes the observed features.

Early emission characterization of TDE2025aarm

Abstract

In this Letter, we present early emission data analysis of the tidal disruption event TDE2025aarm, including optical, UV and X-ray data. At a redshift of z = 0.01368, TDE2025aarm is the second closest TDE ever discovered, offering an unprecedented opportunity to study such phenomena in great details. We observed TDE2025aarm in optical with the Liverpool Telescope for a total of three epochs, and complemented our dataset with ancillary spectroscopic and photometric data. The early optical spectra are characterized by a blue-continuum and helium, hydrogen and possibly Bowen lines typical of H+He events. The optical light curves peak at M_g ~ -18.63 mag and are well described by fallback of a M_star ~ 0.16 M_sun star onto a M_BH ~ 2x10^{7} M_sun black hole. We report Swift-XRT detection in the 0.3-10 keV range, with a total flux of F_X ~ 1.42x10^{-14} erg s-1 cm-2, fitted by a black-body with kT ~ 0.39 keV. This makes TDE2025aarm a new event among optical/UV bright TDEs detected in soft X-rays. Our analysis suggests that the early emission from TDE2025aarm is powered by circularization shocks, and that the delayed accretion scenario best describes the observed features.
Paper Structure (16 sections, 2 equations, 8 figures, 5 tables)

This paper contains 16 sections, 2 equations, 8 figures, 5 tables.

Table of Contents

  1. Introduction
  2. Discovery
  3. Observations and data
  4. Optical
  5. Swift-UVOT
  6. Swift-XRT
  7. Analysis
  8. Spectral analysis
  9. Black-body fit
  10. Fallback modeling
  11. Discussion and Conclusions
  12. XRT analysis
  13. Host modeling with prospector
  14. extrabol fitting
  15. Line fitting details
  16. ...and 1 more sections

Figures (8)

  • Figure 1: Spectral evolution of TDE2025aarm between -29 and +79 days from $t_{\rm p}$. We show the original spectra in gray and the smooth interpolated in purple. For comparison, we show two spectra of AT 2023clx in blue. Fluxes are normalized and offset for visual clarity. The dashed vertical lines are placed on the rest-frame position of the relevant spectral features.
  • Figure 2: Photospheric evolution of TDE2025aarm. Top panel: bolometric luminosity; middle panel: black-body temperature; bottom panel: black-body radius. Gray shaded areas represent 1-$\sigma$ uncertainty.
  • Figure 3: SED fitting of the XRT data. Results for the power-law and black-body models are shown in red and blue lines, respectively.
  • Figure 4: Upper panel: host-galaxy photometry fitting with prospector and corresponding archival data. Lower panel: residuals calculated in magnitudes.
  • Figure 5: Blackbody fits to the SEDs. We show the epochs at which all five filters are available within a window of $\pm$ 1 day. The top left sub-panel is instead obtained with interpolated points.
  • ...and 3 more figures