[論文レビュー] AT2024wpp: An Extremely Luminous Fast Ultraviolet Transient Powered by Accretion onto a Black Hole

Daniel A. Perley, Anna Y. Q. Ho+70 more|arXiv (Cornell University)|Jan 6, 2026

Gamma-ray bursts and supernovae被引用数 0

ひとこと要約

AT2024wppは近傍で極めて輝度の高い高速UV過渡現象で、おそらくブラックホールへの急速な吸収がエネルギー源。多波長フォローアップによりエネルギー収支と中心エンジン風モデルを制約。

ABSTRACT

We present the discovery of AT 2024wpp ("Whippet"), a fast and luminous 18cow-like transient. At a redshift of z=0.0868, revealed by Keck Cosmic Web Imager spectroscopy of its faint and diffuse star-forming host, it is the fourth-nearest example of its class to date. Rapid identification of the source in the Zwicky Transient Facility data stream permitted ultraviolet-through-optical observations to be obtained prior to peak, allowing the first determination of the peak bolometric luminosity (2x10^45 erg/s), maximum photospheric radius (10^15 cm), and total radiated energy (10^51 erg) of an 18cow-like object. We present results from a comprehensive multiwavelength observing campaign, including a far-UV spectrum from the Cosmic Origins Spectrograph on the Hubble Space Telescope and deep imaging extending >100 days post-explosion from the Very Large Telescope, Hubble Space Telescope, Very Large Array, and Atacama Large Millimetre Array. We interpret the observations under a model in which a powerful rapidly-accreting central engine blows a fast (~0.15c) wind into the surrounding medium and irradiates it with X-rays. The high Doppler velocities and intense ionization within this wind prevent any identifiable features from appearing in the ejecta or in the surrounding circumstellar material, even in the far-ultraviolet. Weak H and He signatures do emerge in the spectra after 35 days in the form of double-peaked narrow lines. Each peak is individually narrow (full width ~3000 km/s) but the two components are separated by ~6600 km/s, indicating stable structures of denser material, possibly representing streams of tidal ejecta or an ablated companion star.

研究の動機と目的

• Identify and characterize AT2024wpp and determine its basic energetics and timescales.
• Measure the peak bolometric luminosity, maximum photospheric radius, and total radiated energy.
• Test and constrain the central-engine wind model driving the transient.
• Compare AT2024wpp to the 18cow-like LFBOT class and infer progenitor/system properties.

提案手法

• Discover AT2024wpp in the Zwicky Transient Facility data stream and trigger rapid, comprehensive follow-up.
• Obtain ultraviolet–through–optical observations prior to peak to determine peak properties.
• Carry out a broad multiwavelength campaign including UV spectroscopy (HST COS/STIS), X-ray, optical/NIR spectroscopy, and radio/millimetre imaging (VLA/ALMA).
• Model the event with a central engine that drives a fast wind into the surrounding medium and irradiates it with X-rays.
• Use host galaxy spectroscopy to establish distance and environmental context (z = 0.0868).
• Subsequently compare to other 18cow-like events to place AT2024wpp in the broader transient landscape.

実験結果

リサーチクエスチョン

• RQ1 What is the peak bolometric luminosity and total radiated energy of AT2024wpp?
• RQ2 Does the data support a model with a powerful rapidly accreting central engine (black hole) launching a fast wind that powers the emission?
• RQ3 What are the properties of the ejecta and circumstellar material as inferred from spectroscopy and late-time observations?
• RQ4 How does AT2024wpp compare to other 18cow-like fast luminous blue optical transients in energy source and evolution?

主な発見

• Peak bolometric luminosity: 2×10^45 erg s^-1.
• Maximum photospheric radius: 10^15 cm.
• Total radiated energy: 10^51 erg.
• Redshift/distance: z = 0.0868, making AT2024wpp the fourth-nearest example in its class.
• Event powered by a central engine wind with speeds ~0.15 c irradiating surrounding material; high ionization suppresses early ejecta features.
• Weak H and He signatures emerge after ~35 days as double-peaked narrow lines with delta v ~ 6600 km s^-1 between components (each peak ~3000 km s^-1), suggesting dense, structured material such as tidal ejecta streams or ablated companion material.
• Comprehensive multiwavelength dataset (UV through radio) including far-UV spectra from HST and late-time optical spectra, radio and submillimetre detections, and X-ray behavior consistent with a luminous central engine.