КФУ. Карточка публикации. First tidal disruption events discovered by SRG/eROSITA: X-ray/optical properties and X-ray luminosity function at z

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FIRST TIDAL DISRUPTION EVENTS DISCOVERED BY SRG/EROSITA: X-RAY/OPTICAL PROPERTIES AND X-RAY LUMINOSITY FUNCTION AT Z < 0.6

Форма представления

Статьи в зарубежных журналах и сборниках

Год публикации

2021

Язык

английский

Авторы, сотрудники КФУ

Бикмаев Ильфан Фяритович, автор

Гумеров Рустам Исхакович, автор

Библиографическое описание на языке оригинала

Sazonov S., Gilfanov M., Medvedev P., First tidal disruption events discovered by SRG/eROSITA: X-ray/optical properties and X-ray luminosity function at z < 0.6//MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - 2021. - Vol.508, Is.3. - P.3820-3847.

Аннотация

We present the first sample of tidal disruption events (TDEs) discovered during the SRG all-sky survey. These 13 events were selected among X-ray transients detected in the 0? < l < 180? hemisphere by eROSITA during its second sky survey (2020 June 10 to December 14) and confirmed by optical follow-up observations. The most distant event occurred at z = 0.581. One TDE continued to brighten at least 6 months. The X-ray spectra are consistent with nearly critical accretion on to black holes of a few ×103 to 108M⊙ , although supercritical accretion is possibly taking place. In two TDEs, a spectral hardening is observed 6 months after the discovery. Four TDEs showed an optical brightening apart from the X-ray outburst. The other nine TDEs demonstrate no optical activity. All 13 TDEs are optically faint, with Lg/LX < 0.3 (Lg and LX being the g band and 0.2-6 keV luminosity, respectively). We have constructed a TDE X-ray luminosity function, which can be fit by a power law with a slope of -0.6 ? 0.2, similar to the trend observed for optically selected TDEs. The total rate is estimated at (1.1 ? 0.5) × 10-5 TDEs per galaxy per year, an order of magnitude lower than inferred from optical studies. This suggests that X-ray bright events constitute a minority of TDEs, consistent with models predicting that X-rays can only be observed from directions close to the axis of a thick accretion disc formed from the stellar debris. Our TDE detection threshold can be lowered by a factor of ~2, which should allow a detection of ~700 TDEs by the end of the SRG survey.

Ключевые слова

accretion; accretion discs; black hole physics; quasars: supermassive black holes; X-rays: galaxies; transients: tidal disruption events;

Название журнала

Monthly Notices of the Royal Astronomical Society

URL

https://academic.oup.com/mnras/article-abstract/508/3/3820/6381721?redirectedFrom=fulltext

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https://repository.kpfu.ru/?p_id=260992

Полная запись метаданных

Поле DC	Значение	Язык
dc.contributor.author	Бикмаев Ильфан Фяритович	ru_RU
dc.contributor.author	Гумеров Рустам Исхакович	ru_RU
dc.date.accessioned	2021-01-01T00:00:00Z	ru_RU
dc.date.available	2021-01-01T00:00:00Z	ru_RU
dc.date.issued	2021	ru_RU
dc.identifier.citation	Sazonov S., Gilfanov M., Medvedev P., First tidal disruption events discovered by SRG/eROSITA: X-ray/optical properties and X-ray luminosity function at z < 0.6//MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - 2021. - Vol.508, Is.3. - P.3820-3847.	ru_RU
dc.identifier.uri	https://repository.kpfu.ru/?p_id=260992	ru_RU
dc.description.abstract	Monthly Notices of the Royal Astronomical Society	ru_RU
dc.description.abstract	We present the first sample of tidal disruption events (TDEs) discovered during the SRG all-sky survey. These 13 events were selected among X-ray transients detected in the 0? < l < 180? hemisphere by eROSITA during its second sky survey (2020 June 10 to December 14) and confirmed by optical follow-up observations. The most distant event occurred at z = 0.581. One TDE continued to brighten at least 6 months. The X-ray spectra are consistent with nearly critical accretion on to black holes of a few ×103 to 108M⊙ , although supercritical accretion is possibly taking place. In two TDEs, a spectral hardening is observed 6 months after the discovery. Four TDEs showed an optical brightening apart from the X-ray outburst. The other nine TDEs demonstrate no optical activity. All 13 TDEs are optically faint, with Lg/LX < 0.3 (Lg and LX being the g band and 0.2-6 keV luminosity, respectively). We have constructed a TDE X-ray luminosity function, which can be fit by a power law with a slope of -0.6 ? 0.2, similar to the trend observed for optically selected TDEs. The total rate is estimated at (1.1 ? 0.5) × 10-5 TDEs per galaxy per year, an order of magnitude lower than inferred from optical studies. This suggests that X-ray bright events constitute a minority of TDEs, consistent with models predicting that X-rays can only be observed from directions close to the axis of a thick accretion disc formed from the stellar debris. Our TDE detection threshold can be lowered by a factor of ~2, which should allow a detection of ~700 TDEs by the end of the SRG survey.	ru_RU
dc.language.iso	ru	ru_RU
dc.subject		ru_RU
dc.title	First tidal disruption events discovered by SRG/eROSITA: X-ray/optical properties and X-ray luminosity function at z < 0.6	ru_RU
dc.type	Статьи в зарубежных журналах и сборниках	ru_RU