Einstein Probe

The primary science objectives are:{{cite web|access-date=14 January 2024|language=en|title=Science Objectives Overview |url=https://ep.bao.ac.cn/ep/cms/article/view?id=19|website=Einstein Probe}}

1. Identify inactive black holes to study how matter is precipitated there by detecting the transient events that take the form of X-ray flares;
2. Detect the electromagnetic counterpart of events triggering gravitational waves such as the merger of neutron stars which will be discovered by the next generation of gravitational wave detectors;
3. Carry out permanent monitoring of the entire sky to detect the various transient phenomena and carry out measurements of known variable X-ray sources.

Einstein Probe carries 2 scientific instruments: the Wide-field X-ray Telescope (WXT), and the Follow-up X-ray Telescope (FXT).{{cite web |title=EinsteinProbe |url=https://www.mpe.mpg.de/7867826/EinsteinProbe |website=www.mpe.mpg.de |access-date=28 December 2023 |language=en}} Both telescopes utilize X-ray focusing optics.

• Wide-field X-ray Telescope (WXT): WXT has a new optics design, called "lobster-eye", that has wider field of view. "Lobster-eye" optics was first tested by the Lobster Eye Imager for Astronomy (LEIA) mission, launched in 2022.{{cite web |title=Einstein Probe Time Domain Astronomical Information Center |url=https://ep.bao.ac.cn/ep/cms/article/view?id=91 |website=ep.bao.ac.cn |access-date=28 December 2023 |archive-date=28 December 2023 |archive-url=https://web.archive.org/web/20231228121939/https://ep.bao.ac.cn/ep/cms/article/view?id=91 |url-status=dead }}{{Cite web|url=https://www.space.com/china-lobster-eye-x-ray-telescope-1st-images|title=China tests novel 'lobster eye' X-ray telescope for observing cosmic events|first=Andrew |last=Jones|date=November 25, 2022|website=Space.com}} WXT consists of 12 lobster-eye optics sensor modules, together creating a very large instantaneous field-of-view of 3600 square degrees. The nominal detection bandpass of WXT is 0.5–4.0 keV. Each module weighs 17 kg and has an electrical power consumption of just under 13 W. With the peripherals, the entire telescope weighs 251 kg and has a power consumption of 315 W.

• Follow-up X-ray Telescope (FXT): FXT has optics adopted from eROSITA. "The mirror module consists of 54 nested Wolter mirrors with a focal length of 1600 mm and an effective area of greater than 300 cm² at 1.5 keV."

The probe weights 1450 kg and is {{Nowrap|3 × 3.4 metres}}.

The Einstein Probe was launched on 9 January 2024, at 07:03 UTC by a Long March 2C rocket from the Xichang Satellite Launch Centre in China, and successfully placed in low Earth orbit at an altitude of 600 km{{Cite web|url=https://www.esa.int/ESA_Multimedia/Images/2024/01/Einstein_Probe_lifts_off_on_a_mission_to_monitor_the_X-ray_sky|title=Einstein Probe lifts off on a mission to monitor the X-ray sky|website=www.esa.int}} and an inclination of 29°, giving an orbital period of 96 minutes.{{Cite web |title=Technical details for satellite EINSTEIN PROBE |url=https://www.n2yo.com//satellite/?s=58753 |access-date=2024-03-07 |website=N2YO.com - Real Time Satellite Tracking and Predictions}}

CAS reported that EP "performs as expected in the first month".{{cite web |title=Time Domain Astronomical Information Center |url=https://ep.bao.ac.cn/ep/cms/article/view?id=157 |website=ep.bao.ac.cn |access-date=13 April 2024}} The probe detected fast X-ray transient EP240315a,{{cite web |title=Time Domain Astronomical Information Center |url=https://ep.bao.ac.cn/ep/cms/article/view?id=163 |website=ep.bao.ac.cn |access-date=13 April 2024}} and bright X-ray flares EP240305a{{cite web |title=Time Domain Astronomical Information Center |url=https://ep.bao.ac.cn/ep/cms/article/view?id=162 |website=ep.bao.ac.cn |access-date=13 April 2024}} and EPW20240219aa.{{cite web |title=Time Domain Astronomical Information Center |url=https://ep.bao.ac.cn/ep/cms/article/view?id=158 |website=ep.bao.ac.cn |access-date=13 April 2024}}

On 15 March 2024, the Einstein Probe detected EP240315a, a soft X-ray burst from 12.5 billion light-years away, lasting over 17 minutes—the longest duration observed from such an ancient explosion. Linked to gamma-ray burst GRB 240315C, this event showed a six-minute delay between X-rays and gamma rays, never observed before. ESA notes that these findings challenge existing gamma-ray burst models.{{Cite web|url=https://www.esa.int/Science_Exploration/Space_Science/Einstein_Probe_detects_puzzling_cosmic_explosion|title=Einstein Probe detects puzzling cosmic explosion|website=www.esa.int}}{{Cite journal|url=https://www.nature.com/articles/s41550-024-02449-8|title=Soft X-ray prompt emission from the high-redshift gamma-ray burst EP240315a|first1=Y.|last1=Liu|first2=H.|last2=Sun|first3=D.|last3=Xu|first4=D. S.|last4=Svinkin|first5=J.|last5=Delaunay|first6=N. 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The probe observed an X-ray outburst from EP J0052, a rare binary system of a Be star and a white dwarf (BeWD). After this discovery, several other space telescopes observed the system, including NASA's Swift and NICER, and ESA's XMM-Newton. XMM-Newton did not find the outburst 18 days after the EP's observations.{{cite web |title=Einstein Probe catches X-ray odd couple |date=2025-02-18|website=ESA|url=https://www.esa.int/Science_Exploration/Space_Science/Einstein_Probe_catches_X-ray_odd_couple|access-date=2025-03-01}}{{cite journal |title=Einstein Probe Discovery of EP J005245.1−722843: A Rare Be–White Dwarf Binary in the Small Magellanic Cloud?|date=2025-02-18|url=https://iopscience.iop.org/article/10.3847/2041-8213/ad9580|access-date=2025-03-01|journal=The Astrophysical Journal Letters|volume=980|number=2|publisher=American Astronomical Society}}

• Timeline of artificial satellites and space probes
• List of things named after Albert Einstein
• X-ray astronomy
• List of space telescopes#X-ray

{{reflist|30em}}

• {{cite book |last1=Yuan |first1=Weimin |last2=Zhang |first2=Chen |last3=Chen |first3=Yong |last4=Ling |first4=Zhixing |title=Handbook of X-ray and Gamma-ray Astrophysics |chapter=The Einstein Probe Mission |date=2022 |pages=1–30 |doi=10.1007/978-981-16-4544-0_151-1 |arxiv=2209.09763 |isbn=978-981-16-4544-0 }}

{{Commons category|Einstein Probe}}

• {{Official website}} at NAOC, CAS. {{Webarchive|url=https://web.archive.org/web/20220102002415/http://ep.bao.ac.cn/ |date=January 02, 2022 }}
• [https://www.esa.int/Science_Exploration/Space_Science/Einstein_Probe_factsheet Einstein Probe] at ESA.int
• [https://www.mpe.mpg.de/7867826/EinsteinProbe Einstein Probe] at MPE.MPG.de

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