Detected by ATLAS (Asteroid Terrestrial-impact Last Alert System) on 2024-04-11 03:21:11 UTC · Distance: 22 Million ly (6.7 Mpc) · Significance: Peak V = 12.0 mag (Widely tracked globally)

Discovered in the spiral galaxy NGC 3621 at approximately 22 million light-years, SN 2024ggi offered astronomers a rare close-up look at the terminal demise of a massive star. Prompt spectroscopic follow-up detected early circumstellar flash signatures that rapidly evolved into a classical Type II plateau as the expanding hydrogen envelope expanded and cooled.

Detected by IceCube Neutrino Observatory (South Pole) on 2023-07-12 14:18:22 UTC · Distance: Cosmological / PeV Scale · Significance: 89% Astrophysical Signalness Probability (Gold Alert)

A high-confidence "Gold" alert issued by IceCube with an estimated signalness probability of 89% (sub-millimeter track originating within the Antarctic ice volume). Emitting a deposited energy of ~185 TeV, the event triggered multi-wavelength ground and space-based follow-up campaigns from Fermi, Swift, and optical survey telescopes to search for coincident flaring active galactic nuclei.

Detected by LIGO Livingston / KAGRA / Virgo (O4 Run) on 2023-05-29 18:15:00 UTC · Distance: 650 Million ly (200 Mpc) · Significance: Definitive Detection (FAR < 1 per 10,000 yr)

GW230529 represents a landmark gravitational wave detection by the LIGO-Virgo-KAGRA Collaboration during the O4 run. The primary component was determined to be 2.5 to 4.5 solar masses—placing it squarely in the elusive lower "mass gap" between known neutron stars and stellar-mass black holes. The secondary object was a 1.2 to 2.0 solar mass neutron star.

Detected by Zwicky Transient Facility (ZTF) / Itagaki on 2023-05-19 17:27:15 UTC · Distance: 21 Million ly (6.4 Mpc) · Significance: Peak Magnitude V = 10.8 (Visible in Binoculars)

SN 2023ixf was a brilliant Type II supernova discovered in the spiral arms of Messier 101 (The Pinwheel Galaxy) at a distance of only 21 million light-years. Early "flash spectroscopy" during the first 24 hours revealed intense, narrow emission lines indicating the shock breakout was plowing into dense circumstellar material ejected by the red supergiant progenitor just months before detonation.

Detected by Fermi GBM & GECAM-B on 2023-03-07 15:44:06 UTC · Distance: 950 Million ly (z = 0.065) · Significance: Fermi GBM Fluence Rank #2 in 50 Years

GRB 230307A was an exceptionally bright burst lasting ~200 seconds, which traditionally classified it as a long-duration core-collapse burst. However, follow-up observations with JWST detected a kilonova signature and the unmistakable spectroscopic fingerprint of tellurium (atomic mass 130), proving it originated from a neutron star merger that synthesized heavy r-process elements.

Detected by Fermi GBM, Swift BAT & LHAASO on 2022-10-09 13:16:59 UTC · Distance: 2.4 Billion ly (z = 0.151) · Significance: Historical BOAT (> 50σ trigger)

GRB 221009A was an unprecedented, once-in-10,000-years cosmological blast. Emitting an isotropic-equivalent energy E_iso exceeding 10^55 ergs, the burst completely saturated space-based detectors, perturbed Earth's ionosphere at 500 km altitude, and generated the highest-energy photon ever observed from a GRB: a staggering 18 TeV photon detected by LHAASO in China.

Detected by ASKAP (Australian Square Kilometre Array Pathfinder) on 2022-06-10 04:32:18 UTC · Distance: 8.0 Billion ly (z = 1.016) · Significance: SNR 42.1 (Record Cosmic Fluence)

FRB 20220610A is the most distant and energetic fast radio burst ever recorded. Detected by ASKAP in Western Australia, its extreme dispersion measure (DM = 1458.1 pc cm⁻³) pointed to a deep cosmological origin. Follow-up imaging with ESO's Very Large Telescope (VLT) localized the burst to a dense group of at least five interacting galaxies 8 billion light-years away.

Detected by Zwicky Transient Facility (ZTF) on 2022-02-11 10:42:40 UTC · Distance: 8.5 Billion ly (z = 1.193) · Significance: Relativistic Jet (Lorentz Factor Γ ~ 12)

AT 2022cmc is one of only four confirmed relativistic Tidal Disruption Events (TDEs) ever observed. Discovered as an extremely luminous, rapidly fading optical transient by ZTF, extensive multi-wavelength follow-up revealed a supermassive black hole at z = 1.193 that disrupted a star and launched a relativistic Doppler-boosted jet pointing almost directly at Earth.

Detected by Swift BAT & Fermi GBM on 2021-12-11 13:09:59 UTC · Distance: 1.1 Billion ly (z = 0.076) · Significance: Definitive Kilonova in Long Burst

For five decades, gamma-ray bursts were divided into short (< 2s, mergers) and long (> 2s, massive star collapse). GRB 211211A completely overturned this dogma: lasting 51.4 seconds, its optical and near-infrared afterglow revealed an excess of luminosity caused by a kilonova fueled by radioactive decay of neutron-rich matter, proving a compact binary merger can produce minute-long gamma emission.

Detected by CHIME/FRB & STARE2 on 2020-04-28 14:34:24 UTC · Distance: 30,000 ly (9.0 kpc) · Significance: SNR > 1000 (1.5 Mega-Jansky ms)

A paradigm-shifting event in transient astrophysics. FRB 200428 was detected by CHIME and STARE2 originating from the active Galactic magnetar SGR 1935+2154 inside the Milky Way (approx. 30,000 light-years away). Simultaneous hard X-ray bursts observed by HXMT, INTEGRAL, and Konus-Wind proved beyond doubt that magnetars are capable of producing FRB-scale coherent radio emissions.

Detected by LIGO Hanford, LIGO Livingston & Virgo on 2019-05-21 03:02:29 UTC · Distance: 17.3 Billion ly (5.3 Gpc) · Significance: SNR 14.7 (FAR < 1 in 4,900 yr)

A short-duration gravitational wave burst (approx. 0.1 seconds) resulting from the collision of two massive black holes of 85 M☉ and 66 M☉. The primary black hole fell directly inside the pair-instability supernova mass gap, where stellar core-collapse theoretically cannot produce remnants. The remnant was a 142 M☉ intermediate-mass black hole.

Detected by IceCube Neutrino Observatory (South Pole, Antarctica) on 2017-09-22 20:54:30 UTC · Distance: 4.0 Billion ly (z = 0.3365) · Significance: 3.5σ Astrophysical Association (Historic First)

On September 22, 2017, IceCube detected a single through-going muon neutrino track with a deposited energy of ~290 TeV. An automated alert was routed worldwide in under 43 seconds. Telescopes following the alert found that the blazar TXS 0506+056 (at z = 0.3365, 4 billion light-years) was undergoing its most energetic gamma-ray flaring state in a decade, marking the first confirmed astrophysical neutrino point source.

Detected by LIGO Hanford, LIGO Livingston & Virgo on 2017-08-17 12:41:04 UTC · Distance: 130 Million ly (40 Mpc) · Significance: SNR 32.4 (Historical Milestone)

The foundational milestone of modern multi-messenger astronomy. The coalescence of two neutron stars was detected in gravitational waves, followed 1.7 seconds later by a short gamma-ray burst (GRB 170817A) detected by Fermi-GBM and INTEGRAL, and subsequently identified across the entire electromagnetic spectrum in host galaxy NGC 4993 as kilonova AT 2017gfo.

Detected by Arecibo Observatory / Karl G. Jansky VLA on 2012-11-02 06:47:21 UTC · Distance: 3.0 Billion ly (z = 0.193) · Significance: Thousands of Repeat Bursts Catalogued

FRB 20121102A was the first repeating fast radio burst ever discovered, shattering the theory that all FRBs are cataclysmic one-off events. Localized by the VLA to a low-mass, low-metallicity dwarf galaxy at z = 0.193, it exhibits one of the highest Faraday rotation measures ever observed (|RM| ~ 10^5 rad m⁻²), pointing to an environment near a massive black hole or dense supernova remnant.