arXiv subjects

James C. A. Miller-Jones

Publications and source records attributed to James C. A. Miller-Jones.

At least 19 recordsLinked to original sources

arXiv2026

An Off-Nuclear Tidal Disruption Event Discovered At Late Times: The Case Of TDE 2023mfm

We present the discovery and analysis of the optically selected tidal disruption event (TDE) 2023mfm, which originates from a wandering massive black hole (MBH) in a massive ($\sim 10^{11} \,$M$_{\odot}$) galaxy hosting a central low-luminosity active galactic nucleus (AGN). Our analysis of the ZTF, Lick, Keck, Swift, Chandra, XMM-Newton, HST, and VLA observations reveals that TDE 2023mfm is a TDE-H from a $10^{6.2 \pm 0.5}\,$M$_{\odot}$ black hole which is offset by $0.66 \pm 0.02$" from the center of its host galaxy, corresponding to a projected distance of $1.08 \pm 0.04$ kpc. TDE 2023mfm displays all the traits of optically selected TDEs. The emission remains hot, $T_{\rm bb} \sim 22,000 \pm 1,000$ K, for more than a month after peak, and the $g$-band light curve peaks at $\left( 2.24^{+0.10} _{-0.11} \right) \times 10^{43} \, \rm erg \, s^{-1}$ and stays above half-maximum luminosity for $47.8^{+3.7}_{-3.5}$ days. The late-time optical-to-UV emission observed with the HST suggests the presence of an unresolved stellar population with a stellar mass of $10^7-10^8\,$M$_{\odot}$ at the position of the TDE, possibly being a low-mass dwarf galaxy or a stripped galaxy from a previous minor merger. The radio emission from TDE 2023mfm emerges at least a year after optical discovery, and we find it likely that it originates from a delayed outflow, however, further observations are needed to determine its true origin.

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arXiv2026

JWST/MIRI Spectroscopy of the Quiescent Black Hole X-ray Binary XTE J1118+480: Constraints on Jet and Circumbinary Dust Contributions to the Mid-infrared Emission

We report on JWST/MIRI low-resolution spectroscopy ($5$-$12 μ$m) and imaging ($15$-$25 μ$m) of the black hole X-ray binary XTE~J1118+480 in quiescence, at an X-ray luminosity nine orders of magnitude sub-Eddington, together with contemporaneous optical monitoring and a radio upper limit of $4.5~μ$Jy at 6 GHz. With the donor subtracted, the $5$-$12 μ$m continuum is curved, turning over near $6~μ$m; a single power law is rejected in favor of a $764\pm 9$ K blackbody. Longward of the turnover the spectral index is $α= +1.21\pm0.36$, steeper at the $2σ$ level than the flat to slightly inverted spectrum of a compact jet. Interpreted as synchrotron, the turnover implies equipartition fields of $\sim$$10^{4}$ G on scales of tens of gravitational radii, but the MIRI photometry at $15$-$21~μ$m-taken $2.6$ hr before the spectrum-lies $30$-$90$ per cent above its extrapolation, suggesting a second self-absorbed zone. A single partially self-absorbed jet spectrum can reach the photometry only at the expense of the spectral curvature and the $25.5~μ$m upper limit, so a steady compact jet is disfavored, although not excluded. Representative self-consistent irradiated-disk models instead reproduce the principal features of the $5$-$25~μ$m spectral energy distribution, with a directly illuminated dust wall at $\simeq 5$ binary separations, outside the tidal-truncation radius, and a minimum dust mass of order $10^{22}$ g. This is the first spectroscopic evidence, though not yet conclusive, favoring circumbinary dust over a jet in a quiescent black hole X-ray binary.

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arXiv2026

A Real-Time Jet Laboratory in Swift J1727.8-1613

We present the results of our intensive VLBI campaign on the black-hole low-mass X-ray binary (LMXB) Swift J1727.8-1613 during its 2023-2024 outburst. We observed the repeated quenching and re establishment of the highly-extended continuous jet during several transitions between hard-intermediate and soft-intermediate states, and the repeated ejection of transient jets. Using time-dependent visibility model fitting, we tracked the motion of nine discrete jet knots, obtaining some of the most precise measurements of transient jet proper motions and ejection dates in an LMXB. These ejecta were only detectable for a short time with VLBI, and some showed rapid intra-observation flux density variability that was not captured in image reconstructions. For the first time, we use time-dependent visibility modelling to fit a piecewise model for the jet knot flux densities, allowing us to create complex, non-parametric light curves of their intra-observation variability. We observed the launching of multiple ejecta across several state transitions, however, we could not identify a consistent signature of jet ejection in the available X-ray intensity or hardness data. We constrained the intrinsic speeds and bulk Lorentz factors of the jet knots, finding that Swift J1727.8-1613 launched both mildly relativistic and highly relativistic ejecta throughout its outburst. We used their proper motions to constrain a posterior distribution for the maximum inclination angle of the jet axis, which had 50th, 84th, and 99th percentiles of 40°, 50°, and 66°, respectively. These unique observations of the repeated ejection of transient jets by a single LMXB reveal that fixed parameters such as black-hole mass, black-hole spin, and spin-orbit misalignment do not uniquely determine the varying properties of transient jets, particularly their speeds and Lorentz factors.

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arXiv2026

One year of broadband radio monitoring of the enigmatic transient GRB 250702B reveals the evolution of the relativistic jet

We present an extensive radio monitoring campaign of the unique extragalactic transient GRB 250702B, with observations spanning 0.65-233 GHz from 6-356 d (observer frame) post-discovery. The radio emission shows a smoothly evolving peaked synchrotron spectrum consistent with an adiabatic shock expanding into a stratified ambient medium ($n_e\propto R^{-k}$; $k= 1.5-2$). We detect significant variability in the low frequency ($\leq3$ GHz) light curves which we interpret as interstellar scintillation, placing an approximate bound on the blast wave image size of $1.2\times10^{16}\lesssim R_{\perp} \lesssim 5\times10^{17}$ cm. The temporal evolution of the flux density and critical synchrotron frequencies suggest the shock that powers the radio emission is potentially a wide-angle $θ_j\gtrsim15$ deg, low Lorentz factor ($Γ\lesssim10$) jet, or a narrow $θ_j\lesssim2$ deg highly relativistic jet. A narrow jet is expected for a stellar-mass black hole engine, such as a helium star merger, and the beaming-corrected kinetic energy in this scenario is consistent with the known distribution for long GRBs ($E_K\sim10^{51}$ erg). The wide-angle jet scenario would instead require a progenitor involving prolonged accretion. We derive and show an intermediate or stellar-mass black hole tidal disruption event are viable possibilities. The beaming-corrected kinetic energy in this scenario is on the low end of the known distribution for relativistic SMBH TDEs ($E_K\sim10^{50}$ erg). We disfavour an SMBH TDE due to lack of compatibility with the observed timescales. The detection of a jet shut off within the next year would favour a WD-IMBH TDE due to the shorter theoretical duration of super-Eddington accretion than the main-sequence TDE channels.

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arXiv2026

A new likely pulsar binary in 47~Tucanae from continuum searches

We present evidence that the X-ray source 47~Tuc~W41, long considered to be an X-ray source powered by coronal activity, is actually a redback pulsar binary. The source continually shows $L_X = 3 \times 10^{31}$ erg s$^{-1}$ (0.5--10 keV), which is well in excess of the coronal saturation limit for active binaries in quiescence, but is consistent with the intrabinary shock observed in redback pulsars, as is its photon index of $Γ= 1.4\pm0.1$. In addition, using deep data from the Australia Telescope Compact Array, we show that W41 is a faint ($9.8\pm1.4 μ$Jy at 5.5 GHz) steep spectrum ($α= -1.8\pm0.4$) radio continuum source, as expected for a pulsar. Light curve modelling of Hubble Space Telescope photometry shows evidence for ellipsoidal modulation with mild irradiation of a $\sim 0.5$--$0.55 M_{\odot}$ secondary around an invisible companion, also consistent with the redback interpretation. The precise position of W41, along with its well-measured 10.4-hr orbital period, should enable it to be matched to a newly-discovered radio pulsar in future data. Our result shows that close pulsar binaries are still hiding, misclassified among active binaries, even in well-studied clusters like 47 Tuc.

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arXiv2026

A cooler look at the environment of Cygnus X-1: Searching for dynamical interactions within cold molecular gas

We present IRAM--30m observations aimed at identifying potential outflow-interstellar medium interaction sites in the vicinity of the black hole X-ray binary Cygnus X--1, which displays persistent relativistic jets and a prominent stellar wind. Using this dataset, we construct molecular line emission maps, identifying a never before seen molecular structure potentially linked to X-ray binary-driven feedback. This structure, surrounding the source, exhibits properties consistent with an interaction powered primarily by the stellar wind of the massive stellar companion and further sculpted by the relativistic jets. Our results indicate that multiple outflow mechanisms (stellar winds and relativistic jets) may simultaneously be shaping the interstellar medium around Cygnus X--1, and that molecular line imaging can help to disentangle complex feedback processes in environments where multiple outflows take place.

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arXiv2026

Unveiling Radio Transients with SKAO Telescopes

Transient astrophysics provides a set of unique laboratories for studying fundamental physics. From the launching of powerful relativistic jets to merging neutron stars, highly-magnetised compact objects, or stellar explosions, transients probe the Universe at its most extreme. The SKAO will provide an unrivalled set of capabilities for transient observations on timescales from nanoseconds to decades, opening new discovery space. With its sensitivity, broad spectral coverage, wide field of view, and high survey speed, SKAO will allow us to discover and understand rare events that provide powerful new insights into regimes of high energy density, strong gravity, and intense magnetic fields. Complemented by a suite of multi-wavelength and multi-messenger facilities, and supported by a network of smaller existing radio telescopes and new computational capabilities, SKAO will unveil the most powerful and exotic events in our Universe, addressing some of the key questions in modern astrophysics and cosmology.

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arXiv2026

Transforming X-ray Binary Astrophysics with SKA+VLBI

X-ray binaries (XRBs) are unique laboratories where accretion, jets, strong gravity and magnetic fields can be probed on humanly tractable timescales. The phased SKA-Mid operating as a single, ultra-sensitive Very Long Baseline Interferometry (VLBI) element will transform radio studies of XRBs primarily through its time-domain capabilities: substantially improved sensitivity on VLBI baselines that include SKA-Mid in Bands 2 and 5, together with connected-element SKA-Mid imaging extending down to 0.35--1 GHz (Band 1), microarcsecond-precision astrometry for bright systems, high-fidelity polarimetry for the most strongly polarized sources, and rapid target-of-opportunity response. In synergy with global VLBI networks, SKA+VLBI will track the evolution of compact ejecta and compact jets on astronomical unit (AU) scales, measure frequency-dependent core shifts to infer magnetic field strengths and gradients, resolve disk--jet coupling during state transitions in real time, and determine precise distances and natal kicks via parallaxes and proper motions. Joint campaigns with future X-ray and optical telescopes will enable strictly simultaneous, multi-band constraints on accretion--ejection physics and on jet composition. We outline a quantitative program for \aastar\ and AA4, including cadenced, multi-frequency VLBI ``movies'' of jets over the first days of outbursts, an XRB astrometric census, and a core-shift survey, and we provide representative detection rates, magnetic field measurements and distance accuracies. These outcomes will set the microphysical foundation for jet physics across the mass scale from stellar-mass black holes and neutron stars to active galactic nuclei, and will establish SKA+VLBI as the definitive facility for time-domain, high-resolution XRB astrophysics.

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arXiv2026

Accreting Compact Object Binaries with the SKA

Accreting binary systems provide a time-resolved view of the accretion and ejection processes that are seen in all classes of compact objects, from stellar-mass to supermassive. They allow us to study the launching of relativistic jets on human timescales, probing how the jets are coupled to the underlying accretion flow, and providing unique insights that can be extended to supermassive black holes via the well-established mass scale invariance. Comparative studies of jets from different classes of compact objects allow us to determine the impact of mass, spin, magnetic fields, and stellar surfaces on the launching of jets. The jets from black hole X-ray binaries provide probes of the Galactic black hole population, and an important source of feedback to the surrounding interstellar medium. While existing radio facilities (including the SKA precursors) have made great progress in this field in recent years, the SKA will enhance such studies via its high point source and surface brightness sensitivity, high angular resolution, and broad frequency coverage. This will enable the extension of our existing black hole studies to the fainter accreting neutron star and white dwarf population, the detection of previously-undiscovered systems in a low-luminosity quiescent state, and the extension of our studies to nearby galaxies, revealing rare, high-accretion rate systems that probe a key phase of black hole growth.

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arXiv2026

Rapid jet production and suppression during fast state transitions in the black hole X-ray binary MAXI J1348$-$630

Black hole X-ray binaries (BH XRBs) launch powerful relativistic jets during bright outburst phases. The properties of these outflows change dramatically between different spectral/accretion states. Compact jets are observed during the hard state and are quenched during the soft state, while discrete ejecta are mainly launched during the hard-to-soft state transition. Currently, we do not understand what triggers the formation/destruction of compact jets or the launch of discrete ejecta. In this context, finding a unique link between the jet evolution and the properties of the X-ray emission, such as its fast variability, would imply major progress in our understanding of the fundamental mechanisms that drive relativistic outflows in BH XRBs. Here we show that a brief, strong radio re-brightening during a predominantly soft state of the BH XRB MAXI J1348$-$630 was contemporaneous with a significant increase in the X-ray rms variability observed with NICER in 2019. During this phase, the variability displayed significant changes and, at the same time, MAXI J1348$-$630 launched two relativistic discrete ejecta that we detected with the MeerKAT and ATCA radio-interferometers. We propose that short-lived compact jets were reactivated during this excursion to the hard-intermediate state and were switched off before the ejecta launch, a behavior that has been very rarely observed in these systems. Interestingly, with the caveat of gaps in our radio and X-ray coverage, we suggest a tentative correspondence between the launch of ejecta and the drop in X-ray rms variability in this source, while other typical X-ray signatures associated with discrete ejections are not detected. We discuss how these results provide us with insights into the complex dynamic coupling between the jets and hot corona in BH XRBs.

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arXiv2025

A jet bent by a stellar wind in the black hole X-ray binary Cygnus X-1

Jets provide an important channel for kinetic feedback from accreting black holes into their environment, without which models of the formation of large-scale structure in the universe fail to reproduce the observed properties of galaxies. Hence, an accurate measurement of jet power is critical for understanding black hole growth through accretion and also for quantifying the impact of kinetic feedback. However, the absence of instantaneous jet power measurements has precluded direct comparisons with the accretion luminosity, forcing kinetic feedback models to rely on ad hoc assumptions about how much jet power is released per accreted amount of mass. Here we report the detection of stellar wind-induced bending of the jets in the black hole X-ray binary Cygnus X-1, using 18 years of high-resolution radio imaging. By modeling jet-wind interactions, we determine the current kinetic instantaneous power of the jet to be log$_{10}(L_{\rm jet}/{\rm erg\,s}^{-1}) = 37.3_{-0.2}^{+0.1}$, comparable to the accretion energy determined from its bolometric X-ray luminosity. This result critically places prevailing assumptions about the energetics of black hole powered jets in both galaxy formation simulations, and in scaling models of black hole accretion, on a firm empirical footing.

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arXiv2025

On the distance to the black hole X-ray binary Swift J1727.8$-$1613

We review the existing distance estimates to the black hole X-ray binary Swift J1727.8$-$1613, present new radio and near-UV spectra to update the distance constraints, and discuss the accuracies and caveats of the associated methodologies. We use line-of-sight HI absorption spectra captured using the MeerKAT radio telescope to estimate a maximum radial velocity with respect to the local standard of rest of $24.8 \pm 2.8 \, {\rm km\,s^{-1}}$ for Swift J1727.8$-$1613, which is significantly lower than that of a nearby extragalactic reference source. From this we derive a near kinematic distance of $d_{\rm near} = 3.6 \pm 0.3 \, ({stat}) \pm 2.3 \, ({sys}) \, {\rm kpc}$ as a lower bound after accounting for additional uncertainties given its Galactic longitude and latitude, $(l, b) \approx (8.6^{\circ}, 10.3^{\circ})$. Near-UV spectra from the Hubble Space Telescope's Space Telescope Imaging Spectrograph allows us to constrain the line-of-sight colour excess to $E(B\!-\!V) = 0.37 \pm 0.01 \, ({stat}) \pm 0.025 \, ({sys})$. We then implement this in Monte Carlo simulations and present a distance to Swift J1727.8$-$1613 of $5.5^{+1.4}_{-1.1} \, {\rm kpc}$, under the assumption that the donor star is an unevolved, main sequence K3-5V star. This distance implies a natal kick velocity of $190 \pm 30 \, {\rm km\,s^{-1}}$ and therefore an asymmetrical supernova explosion within the Galactic disk as the expected birth mechanism. A lower distance is implied if the donor star has instead lost significant mass during the binary evolution. Hence, more accurate measurements of the binary inclination angle or donor star rotational broadening from future observations would help to better constrain the distance.

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arXiv2025

The 6 year radio lightcurve of the tidal disruption event AT2019azh

Analysis of radio emission from tidal disruption events allows for detailed constraints on the properties of ejected outflows and the host environment surrounding the black hole. However, the late-time radio behaviour of tidal disruption events is not well-studied due to a lack of observations. In this work we present long-term radio monitoring observations of the tidal disruption event AT2019azh spanning 1167-2159 days post disruption. We fit a physically motivated synchrotron model to the radio spectra at each epoch, and model the decay of the light curve under the assumption that the outflow transitions into the non-relativistic Sedov-Taylor regime at late times. Through this modelling we obtain strong constraints on the density profile of the circumnuclear medium, finding an unusually flat density profile proportional to $r^{0.24^{+0.11}_{-0.15}}$. Overall we find that unlike some tidal disruption events, AT2019azh does not show late time re-brightening up to 6 years post-disruption. The Sedov-Taylor light curve decay model provides a good fit to the data, motivating the assumption that the outflow was produced by a single ejection of material close to the time of stellar disruption. From forward modelling the evolution of the radio light curve decay we predict that the radio afterglow from AT2019azh should be detectable for decades at its current rate of evolution.

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arXiv2025

Dichotomy in Long-Lived Radio Emission from Tidal Disruption Events AT 2020zso and AT 2021sdu: Multi-Component Outflows vs. Host Contamination

We present a detailed radio study of the tidal disruption events (TDEs) AT 2020zso and AT 2021sdu. Both exhibit transient radio emission beginning shortly after optical discovery and persisting for several years. For AT 2020zso, we identify two distinct radio flares. The first arises soon after the optical peak, reaching a maximum $\sim1$ year post-discovery before fading. The second flare appears $\sim800$ days after discovery and results in the brief presence of two distinct components in the radio spectra, providing strong evidence for physically separate outflows. Both flares are consistent with non-relativistic outflows, with velocities $v\approx0.1-0.2c$ and energies $E\sim10^{49}$ erg, propagating through a Bondi-like circumnuclear medium. Our analysis supports a scenario in which the first outflow is accretion-driven, launched while the TDE disk is accreting at a relatively high Eddington fraction, whereas the second outflow is associated with a transition to an advection-dominated accretion flow. In contrast, the radio emission from AT 2021sdu is best explained by a slower ($v\approx0.03c$), less energetic outflow ($E\sim10^{48}$ erg), combined with diffuse, non-variable host emission that becomes dominant $\sim500$ days after discovery. Assuming free expansion, we infer an outflow launch date preceding the optical discovery date. This suggests that the outflow may originate from either the unbound stellar debris ejected during disruption or, alternatively, from a decelerating outflow. Our findings demonstrate the diversity of outflow properties in TDEs and highlight the observational challenges of interpreting late-time radio variability in the presence of host galaxy contamination.

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arXiv2025

New Metrics for Identifying Variables and Transients in Large Astronomical Surveys

A key science goal of large sky surveys such as those conducted by the Vera C. Rubin Observatory and precursors to the Square Kilometre Array is the identification of variable and transient objects. One approach is the statistical analysis of the time series of the changing brightness of sources, that is, their light curves. However, finding adequate statistical representations of light curves is challenging because of data quality issues such as sparsity of observations, irregular sampling, and other nuisance factors inherent in astronomical data collection. The wide diversity of objects that a large-scale survey will observe also means that making parametric assumptions about the shape of light curves is problematic. We present a Gaussian process (GP) regression approach for characterising light curve variability that addresses these challenges. Our approach makes no assumptions about the shape of a light curve and, therefore, is general enough to detect a range of variable source types. In particular, we propose using the joint distribution of GP amplitude hyperparameters to distinguish variable and transient candidates from nominally stable ones and apply this approach to 6394 radio light curves from the ThunderKAT survey. We compare our results with two variability metrics commonly used in radio astronomy, namely $η_ν$ and $V_ν$, and show that our approach has better discriminatory power and interpretability. Finally, we conduct a rudimentary search for transient sources in the ThunderKAT dataset to demonstrate how our approach might be used as an initial screening tool. Computational notebooks in Python and R are available to help facilitate the deployment of this framework to other surveys.

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arXiv2025

The First Radio-Bright Off-Nuclear TDE 2024tvd Reveals the Fastest-Evolving Double-Peaked Radio Emission

We present the first multi-epoch broadband radio and millimeter monitoring of an off-nuclear TDE using the VLA, ALMA, ATA, AMI-LA, and the SMA. The off-nuclear TDE 2024tvd exhibits double-peaked radio light curves and the fastest evolving radio emission observed from a TDE to date. With respect to the optical discovery date, the first radio flare rises faster than $F_{\rm ν} \sim t^{9}$ at $Δt = 88-131$ days, and then decays as fast as $F_{\rm ν} \sim t^{-6}$. The emergence of a second radio flare is observed at $Δt \approx 194$ days with an initial fast rise of $F_{\rm ν} \sim t^{18}$, and an optically thin decline of $F_{\rm ν} \sim t ^{-12}$. We interpret these observations in the context of a self-absorbed and free-free absorbed synchrotron spectrum, while accounting for both synchrotron and external inverse-Compton cooling. We find that a single prompt outflow cannot easily explain these observations and it is likely that either there is only one outflow that was launched at $Δt \sim 80$ days, or two distinct outflows, with the second launched at $Δt \sim 170-190$ days. The nature of these outflows, whether sub-, mildly-, or ultra-relativistic, is still unclear, and we explore these different scenarios. Finally, we find a temporal coincidence between the launch time of the first radio-emitting outflow and the onset of a power-law component in the X-ray spectrum, attributed to inverse-Compton scattering of thermal photons.

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arXiv2025

Optically Overluminous Tidal Disruption Events: Outflow Properties and Implications for Extremely Relativistic Disruptions

Recent studies suggest that tidal disruption events (TDEs) with off-axis jets may manifest as optically overluminous events. To search for jet signatures at late times, we conducted radio observations of eight such optically overluminous ($M_{g, \rm peak} < -20.8$ mag) TDEs with the Very Large Array. We detect radio counterparts in four events. The observed radio luminosities ($L_{\rm 6 GHz} \sim 10^{38}$--$10^{39}$ erg s$^{-1}$) are two orders of magnitude lower than those of on-axis jetted TDEs, and we find no evidence for off-axis jets within rest-frame time of 3 yrs. Two of them (AT2022hvp and AT2021aeou) exhibit evolving radio emission, consistent with synchrotron emission from non-relativistic outflows launched near the time of first optical light. Two events (AT2020ysg and AT2020qhs) show no statistically significant variability, which can be attributed to either non-relativistic outflows or pre-existing active galactic nuclei. Compared to a control sample of fainter TDEs with $M_{g, \rm peak} > -20.5$ mag observed at similar rest-frame timescales ($t_{\rm rest} ~ 1.5$\,yr), our sample shows systematically more luminous radio emission, suggesting that optically overluminous TDEs may launch more powerful prompt non-relativistic outflows. We speculate that strong general relativistic effects near high-mass black holes ($M_{\rm BH} ~ 10^8\,M_\odot$) may play a key role. These findings motivate further investigation into the nature of relativistic disruptions around massive black holes and the physical conditions necessary for jet formation.

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arXiv2025

A new Bowen Fluorescence Flare and Extreme Coronal Line Emitter discovered by SRG/eROSITA

The nuclear transient eRASSt J012026.5-292727 (J012026 hereafter) was discovered in the second SRG/eROSITA all-sky survey (eRASS2). The source appeared more than one order of magnitude brighter than the eRASS1 upper limits (peak eRASS2 0.2-2.3 keV flux of 1.14 x 10^-12 erg cm^-2 s^-1), and with a soft X-ray spectrum (photon index Gamma = 4.3). Over the following months, the X-ray flux started decaying, with significant flaring activity on both hour- and year-timescales. By inspecting the multiwavelength light curves of time-domain wide-field facilities, we detected a strong mid-infrared flare, evolving over 2 years, and a weaker optical counterpart. Follow-up optical spectroscopy revealed transient features, including redshifted Balmer lines (FWHM ~1500 km/s), strong Fe II emission, He II and Bowen lines, and high-ionization iron coronal lines. One spectrum showed a triple-peaked H-beta line, consistent with emission from a face-on elliptical disk. The spectroscopic features and the slow evolution of the event place J012026 within the classifications of Bowen fluorescence flares (BFFs) and extreme coronal line emitters (ECLEs). BFFs have been associated with rejuvenated accreting SMBHs, although the mechanism triggering the onset of the new accretion flow is still unclear, while ECLEs have been linked to the disruption of stars in gas-rich environments. The association of J012026 to both classes, combined with the multi-wavelength information, suggests that BFFs could be, at least in some cases, due to tidal disruption events (TDEs). The observed X-ray variability, uncommon in standard TDEs, adds complexity to these families of nuclear transients. These results highlight the diverse phenomenology of nuclear accretion events and demonstrate the value of systematic X-ray surveys, such as eROSITA and Einstein Probe, for uncovering such transients and characterizing their physical origin.

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