{{Short description|Astronomical event}} {{use dmy dates|cs1-dates=ly|date=May 2023}} thumb|(Upper) Light curve of AT2021lwx. (Lower left) Pan-STARRS upper limits up to 750 d (rest frame) before the first detection of AT2021lwx. (Lower right) Comparison to similar transients.<ref name=Wiseman2023/> thumb|Rest-frame UV and optical spectra of AT2021lwx and similar objects.<ref name=Wiseman2023/> '''AT 2021lwx''' (also known as '''ZTF20abrbeie''' or "Scary Barbie"<ref name=":0">{{Cite journal |last1=Subrayan |first1=Bhagya M. |last2=Milisavljevic |first2=Dan |last3=Chornock |first3=Ryan |last4=Margutti |first4=Raffaella|author4-link=Raffaella Margutti |last5=Alexander |first5=Kate D. |last6=Ramakrishnan |first6=Vandana |last7=Duffell |first7=Paul C. |last8=Dickinson |first8=Danielle A. |last9=Lee |first9=Kyoung-Soo |last10=Giannios |first10=Dimitrios |last11=Lentner |first11=Geoffery |last12=Linvill |first12=Mark |last13=Garretson |first13=Braden |last14=Graham |first14=Matthew J. |last15=Stern |first15=Daniel |date=2023-05-10 |title=Scary Barbie: An Extremely Energetic, Long-duration Tidal Disruption Event Candidate without a Detected Host Galaxy at z = 0.995 |journal=The Astrophysical Journal Letters |volume=948 |issue=2 |pages=L19 |arxiv=2302.10932 |bibcode=2023ApJ...948L..19S |doi=10.3847/2041-8213/accf1a |issn=2041-8205 |doi-access=free}}</ref>) is the most energetic non-quasar optical transient astronomical event ever observed, with a peak luminosity of {{Convert|7e45|erg/s|W|disp=out}} and a total radiated energy of {{Convert|9.7e52-1.5e53|erg|J|disp=out}} over three years.<ref name=":0" /><ref name="Wiseman2023">{{Cite journal |last1=Wiseman |first1=p. |last2=Wang |first2=Y. |last3=Hönig |first3=S. |last4=Castero-Segura |first4=N. |last5=Clark |first5=P. |last6=Frohmaier |first6=C. |last7=Fulton |first7=M. D. |last8=Leloudas |first8=G. |last9=Middleton |first9=M. |last10=Müller-Bravo |first10=T. E. |last11=Mummery |first11=A. |last12=Pursiainen |first12=M |last13=Smartt |first13=S. J. |last14=Smith |first14=K. |last15=Sullivan |first15=M. |date=11 April 2023 |title=Multiwavelength observations of the extraordinary accretion event AT 2021lwx |journal=Monthly Notices of the Royal Astronomical Society |volume=522 |issue=3 |pages=3992–4002 |arxiv=2303.04412 |doi=10.1093/mnras/stad1000 |doi-access=free}}</ref> 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<ref>J. Nordin, V. Brinnel, J. van Santen, A. Gal-Yam, O. Yaron, S. Schulze (10 May 2021). [https://www.wis-tns.org/object/2021lwx/discovery-cert "Discovery certificate for object 2021lwx"]. IAU Transient Name Server.</ref> and is believed to be due to the accretion of matter into a super massive black hole (SMBH) heavier than one hundred million solar masses ({{solar mass}}).<ref name=":0" /><ref name=Wiseman2023/><ref name="NYT-20230512">{{cite news |last=Overbye |first=Dennis |authorlink=Dennis Overbye |title=The Biggest Explosion in the Cosmos Just Keeps Going - For three years, telescopes have monitored "one of the most luminous" events ever: a supermassive black hole consuming a gigantic cloud of interstellar gas. |url=https://www.nytimes.com/2023/05/12/science/astronomy-black-hole.html |date=12 May 2023 |work=The New York Times |url-status=live |archiveurl=https://archive.today/20230512191540/https://www.nytimes.com/2023/05/12/science/astronomy-black-hole.html |archivedate=12 May 2023 |accessdate=13 May 2023 }}</ref> It has a redshift of z = 0.9945,<ref name=Wiseman2023/> which would place it at a distance of about eight billion light-years from earth,<ref name="NYT-20230512"/> and is located in the constellation Vulpecula.<ref name=Kahlon>{{Cite web |author-last=Kahlon |author-first=Gurjeet |date=5 November 2023 |title=Astronomers reveal the largest cosmic explosion ever seen |website=Royal Astronomical Society |url=https://ras.ac.uk/news-and-press/news/astronomers-reveal-largest-cosmic-explosion-ever-seen |access-date=11 May 2023 }}</ref> No host galaxy has been detected.<ref name=":0" /><ref name=Wiseman2023/>
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 (ATLAS) as ATLAS20bkdj, and the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) as PS22iin. At the Neil Gehrels Swift Observatory, X-ray observations were made with the X-ray Telescope and ultraviolet, with the Ultraviolet-Optical Telescope (UVOT).<ref name=":0" /><ref name=Wiseman2023/>
The inferred mass of the SMBH, based on the light to mass ratio, is about {{Val||ul=solar mass|p=10<sup>8</sup>–|e=9}}, given the observed brightness. However, the theoretical limit for a black hole to tidally disrupt a solar-mass star is {{Val||u=solar mass|e=8}}. If AT 2021lwx is a tidal disruption event, then the disrupted star must have been much more massive than the sun.<ref>{{Cite journal |date=2019-02-20 |title=Weighing Black Holes Using Tidal Disruption Events |doi=10.3847/1538-4357/ab010f |language=en-us |doi-access=free |last1=Mockler |first1=Brenna |last2=Guillochon |first2=James |last3=Ramirez-Ruiz |first3=Enrico |journal=The Astrophysical Journal |volume=872 |issue=2 |page=151 |arxiv=1801.08221 |bibcode=2019ApJ...872..151M }}</ref> {{Citation needed|date=May 2023}}
Subrayan et al. originally interpreted it to be a tidal disruption event between an SMBH (~{{Val||u=solar mass|e=8}}) and a massive star (~{{Val|14|u=solar mass}}).<ref name=":0" /> Wiseman et al. reached a similar conclusion, but given the low probability of such an event, posited another scenario: "the sudden accretion of a large amount of gas, potentially a giant molecular cloud"<ref name="Wiseman2023" /> (~{{Val||u=solar mass|e=3}}),<ref>{{Cite web |date=2023-05-11 |title=This Is The Largest Cosmic Explosion In The Universe Ever Seen |url=https://www.iflscience.com/this-is-the-largest-cosmic-explosion-in-the-universe-ever-seen-68893 |access-date=2023-05-15 |website=IFLScience |language=en}}</ref> onto an SMBH (>{{Val||u=solar mass|e=8}}).<ref name="Wiseman2023" /><ref>{{Cite web |title='Terrifying': Why the universe's largest cosmic explosion is called 'Scary Barbie' |url=https://www.usatoday.com/story/news/nation/2023/05/12/largest-space-explosion-scary-barbie-black-hole/70212322007/ |access-date=2023-05-15 |website=USA TODAY |language=en-US}}</ref>
== See also == * Ophiuchus Supercluster eruption, a {{Convert|5e61|erg|J|adj=on|disp=out}} event that may have occurred up to 240 million years ago, revealed by a giant radio fossil * MS 0735.6+7421, a {{Convert|1e61|erg|J|adj=on|disp=out}} eruption that has been occurring for the last 100 million years * GRB 080916C, an {{Convert|8.8e54|erg|J|adj=on|disp=out}} gamma-ray burst seen in 2008<ref>{{Cite journal |author=Fermi LAT and Fermi GBM Collaborations |date=27 March 2009 |title=Fermi Observations of High-Energy Gamma-Ray Emission from GRB 080916C |journal=Science |volume=323 |issue=5922 |pages=1688–1693 |doi=10.1126/science.1169101 |pmid=19228997 |bibcode=2009Sci...323.1688A |s2cid=263421340 |doi-access=free }}</ref> * GRB 221009A, a {{Convert|1.2e55|erg|J|adj=on|disp=out}} gamma-ray burst seen in 2023<ref>{{Cite journal |last1=Burns |first1=Eric |last2=Svinkin |first2=Dmitry |last3=Fenimore |first3=Edward |last4=Kann |first4=D. Alexander |last5=Agüí Fernández |first5=José Feliciano |last6=Frederiks |first6=Dmitry |last7=Hamburg |first7=Rachel |last8=Lesage |first8=Stephen |last9=Temiraev |first9=Yuri |last10=Tsvetkova |first10=Anastasia |last11=Bissaldi |first11=Elisabetta |last12=Briggs |first12=Michael S. |last13=Dalessi |first13=Sarah |last14=Dunwoody |first14=Rachel |last15=Fletcher |first15=Cori |date=2023-03-01 |title=GRB 221009A: The BOAT |journal=The Astrophysical Journal Letters |volume=946 |issue=1 |pages=L31 |doi=10.3847/2041-8213/acc39c |arxiv=2302.14037 |bibcode=2023ApJ...946L..31B |issn=2041-8205 |doi-access=free }}</ref> * {{annotated link|Hypernova}}
== References == {{reflist}} {{2023 in space}} {{Vulpecula}}
Category:Astronomical objects discovered in 2023 Category:Astronomical events Category:Supermassive black holes Category:Vulpecula