EP260321a is a thermal soft X-ray shock breakout from a ~300 R_⊙ CSM shell around a stripped-envelope progenitor, followed by SN Ic-BL 2026gzf.
Science objectives of the Einstein Probe mission
7 Pith papers cite this work. Polarity classification is still indexing.
abstract
The Einstein Probe (EP) is an interdisciplinary mission of time-domain and X-ray astronomy. Equipped with a wide-field lobster-eye X-ray focusing imager, EP will discover cosmic X-ray transients and monitor the X-ray variability of known sources in 0.5-4 keV, at a combination of detecting sensitivity and cadence that is not accessible to the previous and current wide-field monitoring missions. EP can perform quick characterisation of transients or outbursts with a Wolter-I X-ray telescope onboard. In this paper, the science objectives of the Einstein Probe mission are presented. EP is expected to enlarge the sample of previously known or predicted but rare types of transients with a wide range of timescales. Among them, fast extragalactic transients will be surveyed systematically in soft X-rays, which include {\gamma}-ray bursts and their variants, supernova shock breakouts, and the predicted X-ray transients associated with binary neutron star mergers. EP will detect X-ray tidal disruption events and outbursts from active galactic nuclei, possibly at an early phase of the flares for some. EP will monitor the variability and outbursts of X-rays from white dwarfs, neutron stars and black holes in our and neighbouring galaxies at flux levels fainter than those detectable by the current instruments, and is expected to discover new objects. A large sample of stellar X-ray flares will also be detected and characterised. In the era of multi-messenger astronomy, EP has the potential of detecting the possible X-ray counterparts of gravitational wave events, neutrino sources, and ultra-high energy {\gamma}-ray and cosmic ray sources. EP is expected to help advance the studies of extreme objects/phenomena and their underlying physical processes revealed in the dynamic X-ray universe, as well as studies in other areas of X-ray astronomy.
representative citing papers
EP250827b/SN 2025wkm is a new X-ray flash–supernova whose long, soft X-ray burst and double-peaked, plateauing optical light curve are best explained by a magnetar central engine interacting with a low-mass circumstellar shell.
Future CE+ET detectors may detect lensed BNS kilonovae at ~0.5/yr via pointed follow-up of known galaxy lenses, while lensed sGRBs and afterglows remain rare or undetectable with current-generation facilities.
Long gamma-ray bursts imply a higher cosmic star formation rate density at z>6 than galaxy surveys detect, sufficient to drive reionization with moderate ionizing efficiency and escape fraction, implying a large population of undetected faint galaxies.
The paper identifies supernova emission matching a scaled SN 1998bw template in the late-time light curve of EP250302a at z=1.131, with early data constraining the jet Lorentz factor above 25.
EP260321a is identified as the faintest shock breakout X-ray transient associated with broad-lined Ic supernova SN 2026gzf, interpreted as originating from a mildly relativistic weak outflow choked inside the progenitor star.
GRB 260310A/SN 2026fgk is a spectroscopically confirmed Type Ic-BL supernova at z=0.153 with 0.4-0.6 times the luminosity of SN 1998bw, nickel mass 0.4-0.5 solar masses, ejected mass 4-6 solar masses, kinetic energy (3-8) x 10^51 erg, and located at a 15 kpc offset due to the host's extended light p
citing papers explorer
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X-rays breaking out of pre-explosion ejecta mark a supernova's first light
EP260321a is a thermal soft X-ray shock breakout from a ~300 R_⊙ CSM shell around a stripped-envelope progenitor, followed by SN Ic-BL 2026gzf.
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EP250827b/SN 2025wkm: An X-ray Flash-Supernova Powered by a Central Engine and Circumstellar Interaction
EP250827b/SN 2025wkm is a new X-ray flash–supernova whose long, soft X-ray burst and double-peaked, plateauing optical light curve are best explained by a magnetar central engine interacting with a low-mass circumstellar shell.
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Prospect for Detection of Strongly Lensed Multi-messenger Signals of Binary Neutron Star Mergers
Future CE+ET detectors may detect lensed BNS kilonovae at ~0.5/yr via pointed follow-up of known galaxy lenses, while lensed sGRBs and afterglows remain rare or undetectable with current-generation facilities.
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Gamma-ray bursts reveal the history and faint contributors of cosmic reionization
Long gamma-ray bursts imply a higher cosmic star formation rate density at z>6 than galaxy surveys detect, sufficient to drive reionization with moderate ionizing efficiency and escape fraction, implying a large population of undetected faint galaxies.
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Discovery of a Supernova Following the Einstein Probe Transient EP250302a at z = 1.131
The paper identifies supernova emission matching a scaled SN 1998bw template in the late-time light curve of EP250302a at z=1.131, with early data constraining the jet Lorentz factor above 25.
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EP260321a/SN 2026gzf: The Faintest Shock Breakout Associated with a Broad-Lined Supernova
EP260321a is identified as the faintest shock breakout X-ray transient associated with broad-lined Ic supernova SN 2026gzf, interpreted as originating from a mildly relativistic weak outflow choked inside the progenitor star.
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GRB 260310A/SN 2026fgk: Photometric and Spectroscopic Evolution of a Nearby GRB-Supernova and an Exceptionally Bright Afterglow at z=0.153
GRB 260310A/SN 2026fgk is a spectroscopically confirmed Type Ic-BL supernova at z=0.153 with 0.4-0.6 times the luminosity of SN 1998bw, nickel mass 0.4-0.5 solar masses, ejected mass 4-6 solar masses, kinetic energy (3-8) x 10^51 erg, and located at a 15 kpc offset due to the host's extended light p