We carried out a follow-up X-ray observation of the nearby tidal disruption event (TDE) AT 2025aarm (O'Neill et al. 2025, TNS Discovery Report 4156; Faris et al., AstroNote 2025-311) using the Chandra X-ray Observatory with the ACIS-S instrument (PI Wichern; ObsID 32275). The observation was performed on 2026 April 11 between 18:26 and 23:18 UTC (MJD 61141.77 - 61141.97), approximately 167 days after the optical discovery, for a net exposure of 14.7 ks.
An X-ray source is clearly detected at the known optical position of the transient. From the source region, we measure an average count rate of 0.006(1) counts/s in the 0.5-7 keV energy band. The 0.5-10 keV spectrum can be described by an absorbed power-law model. Considering a Galactic hydrogen column density of 4e20 cm^-2, we obtain a best-fit photon index of 1.6(0.4) and a power-law normalization of 2.6(1)x10^-5. The parameter uncertainties are given for 90% confidence range. The unabsorbed flux in the 0.5-7 keV band is estimated to be 1.4(2)×10^-13 erg/cm2/s, corresponding to a luminosity of 6.3e40 erg/s at a distance of 61.5 Mpc. This represents an increase by a factor of ~24 compared to earlier Chandra observation on 2025 November 5 (Somalwar et al., AstroNote 2025-316), indicating X-ray brightening during the declining phase of the optical emission.
We thank the Chandra PI and the team for accepting and executing our DDT request.
| Catalog | Name | Reported RA | Reported DEC | Reported Obj-Type | Reported Redshift | Host Name | Host Redshift | Remarks | TNS RA | TNS DEC | TNS Obj-Type | TNS Redshift |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| TNS | 2025aarm | 04:32:12.399 | -05:22:39.51 | TDE | 0.01368 | 04:32:12.399 | -05:22:39.51 | TDE | 0.01368 |
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