AT 2021lwx (also known as ZTF20abrbeie or "Scary Barbie") is the most energetic non-

quasar A quasar ( ) is an extremely Luminosity, luminous active galactic nucleus (AGN). It is sometimes known as a quasi-stellar object, abbreviated QSO. The emission from an AGN is powered by accretion onto a supermassive black hole with a mass rangi ...

optical transient astronomical event ever observed, with a peak luminosity of 7 × 10⁴⁵

erg The erg is a unit of energy equal to 10−7joules (100Nano-, nJ). It is not an SI unit, instead originating from the centimetre–gram–second system of units (CGS). Its name is derived from (), a Greek language, Greek word meaning 'work' or ' ...

per second (erg s⁻¹) and a total radiated energy between 9.7 × 10⁵² erg to 1.5 × 10⁵³ erg over three years. Despite being lauded as the largest explosion ever, GRB 221009A was both more energetic and brighter. It was first identified in imagery obtained on 13 April 2021 by the Zwicky Transient Facility (ZTF) astronomical survey and is believed to be due to the accretion of matter into a super massive black hole (SMBH) heavier than one hundred million

solar mass The solar mass () is a frequently used unit of mass in astronomy, equal to approximately . It is approximately equal to the mass of the Sun. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxie ...

es (). It has a

redshift In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and increase in frequency and e ...

of z = 0.9945, which would place it at a distance of about eight billion

light-year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astr ...

s from earth, and is located in the constellation

Vulpecula Vulpecula is a faint constellation in the northern sky. Its name is Latin for "little fox", although it is commonly known simply as the fox. It was identified in the seventeenth century, and is located in the middle of the Summer Triangle (an ...

. No host

galaxy A galaxy is a Physical system, system of stars, stellar remnants, interstellar medium, interstellar gas, cosmic dust, dust, and dark matter bound together by gravity. The word is derived from the Ancient Greek, Greek ' (), literally 'milky', ...

has been detected. Forced photometry of earlier ZTF imagery showed AT 2021lwx had already begun brightening by 16 June 2020, as ZTF20abrbeie. It was also detected independently in data from the

Asteroid Terrestrial-impact Last Alert System The Asteroid Terrestrial-impact Last Alert System (ATLAS) is a robotic astronomical survey and early warning system optimized for detecting smaller near-Earth objects a few weeks to days before they Impact event, impact Earth. Funded by NASA, an ...

(ATLAS) as ATLAS20bkdj, and the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) as PS22iin. At the

Neil Gehrels Swift Observatory Neil Gehrels Swift Observatory, previously called the Swift Gamma-Ray Burst Explorer, is a NASA three-telescope space observatory for studying gamma-ray bursts (GRBs) and monitoring the afterglow in X-ray, and UV/visible light at the location o ...

, X-ray observations were made with the X-ray Telescope and

ultraviolet Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of ...

, with the Ultraviolet-Optical Telescope (UVOT). Subrayan et al. originally interpreted it to be a

tidal disruption event A tidal disruption event (TDE) is a time-domain astronomy, transient astronomical source produced when a star passes so close to a supermassive black hole (SMBH) that it is pulled apart by the black hole's tidal force. The star undergoes spaghett ...

between an SMBH (~10⁸ ) and a massive star (~14 ). Wiseman et al. disfavor this interpretation, and instead believe the most likely scenario is "the sudden accretion of a large amount of gas, potentially a giant molecular cloud" (~1,000 ), onto an SMBH (>10⁸ ). The inferred mass of the SMBH, based on the light to mass ratio, is about 1 hundred million - 1 billion solar masses, given the observed brightness. However, the theoretical limit for an accreting super massive black hole is 1 hundred million solar masses. Given the best understood model of accreting SMBH's, this even may be the most massive SMBH to possibly accrete matter.

References

{{Vulpecula Astronomical objects discovered in 2023 Astronomical events Supermassive black holes Vulpecula

See also

References