GCN Circulars
GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search
To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.
Advanced Search Examples (click to copy):
subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
10364 results found.
- Konus-Wind detection of GRB 250215A / EP250215a
- GRB 250217C: COLIBRÍ/DDRAGO Upper Limits on the Optical Counterpart
- GRB 250217C: SVOM/GRM observation
- SVOM/sb25021804: SVOM detection of a long X-ray transient
- GRB 250213A: Swift-XRT observations
- GRB 250216A: AstroSat CZTI detection
- GRB 250217C: AstroSat CZTI detection of a short burst
- Fermi GRB 250217A: Global MASTER-Net observations report
- GRB 250216A: Fermi GBM Final Real-time Localization
- GRB 250215A: Swift-XRT refined Analysis
- EP250215a / GRB 250215A: AstroSat CZTI detection
- EP250215a: Global MASTER-Net observations report
- EP250215a: EP-WXT detection and FXT follow-up observation of an X-ray transient
- Fermi GRB 250215A: Global MASTER-Net observations report
- Fermi trigger No 761206993: Global MASTER-Net observations report
- EP250212a: Liverpool Telescope optical upper limits
- EP250212a: EP-WXT detection and FXT follow-up observation of a fast X-ray transient
- Fermi GRB 250212A: Global MASTER-Net observations report
- Fermi trigger No 760945500: Global MASTER-Net observations report
- GRB 250211B: A long GRB detected by INTEGRAL
- LIGO/Virgo/KAGRA S250206dm: GECKO Continued Observaiton with 7DT
- GRB 250207A: Fermi GBM Observation
- Konus-Wind detection of GRB 250207A
- Konus-Wind detection of GRB 250206A
- EP250207b: Global MASTER-Net observations report
- GRB 250207A: Skynet optical afterglow observations
- GRB 250210A: AstroSat CZTI detection
- EP250207b: a new X-ray transient detected by Einstein Probe
- GRB 250209A: MAXI/GSC detection (possible detection of an X-ray flare from 1RXS J145110.3+310648)
- Fermi GRB 250210A: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S250206dm: Global MASTER-Net observations report
- IceCube Alert 250207.09: Global MASTER-Net observations report
- Fermi-LAT Gamma-ray Observations of IceCube-250207A
- LIGO/Virgo/KAGRA S250207bg: Updated NED Galaxies in the Localization Volume
- LIGO/Virgo/KAGRA S250206dm: GECKO Observation with 7DT and KMTNet
- LIGO/Virgo/KAGRA S250206dm: (Update-7) NED Galaxies in the Localization Volume
- GRB 250206A: Fermi-LAT detection
- LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the DDOTI optical candidates
- GRB 250207A: Swift-XRT refined Analysis
- LIGO/Virgo/KAGRA S250207bg: NED Galaxies in the Localization Volume
- Konus-Wind detection of GRB 250204B
- GRB 250129A: Continued AbAO and Mondy optical observations
- GRB 250207B: MAXI/GSC detection
- The EP-WXT trigger 01709131332 is likely a flaring star
- LIGO/Virgo/KAGRA S250206dm: Updated-6 NED Galaxies in the Localization Volume
- Fermi-LAT Gamma-ray Observations of IceCube-250203A
- LIGO/Virgo/KAGRA S250206dm: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S250206dm: Updated NED Galaxies in the Localization Volume
- LIGO/Virgo/KAGRA S250206dm: NED Galaxies in the Localization Volume
- EP250205a/GRB 250205A: Einstein Probe observation
- LIGO/Virgo/KAGRA S250205bk: NED Galaxies in the Localization Volume
- Konus-Wind detection of GRB 250201A
- Konus-Wind detection of GRB 250202B
- GRB 250204B: AstroSat CZTI detection of a short burst
- GRB 250202C: GRBAlpha detection
- GRB 250129A: 7DT Detection and Medium-band SED of Afterglow
- GRB 250202C: Fermi GBM Final Real-time Localization
- GRB 250202B: AstroSat CZTI detection of a bright long GRB
- Swift GRB250129A: MASTER 4 days observations report
- GRB 250201A: INTEGRAL SPI/ACS detection
- Konus-Wind detection of GRB 250129A
- LIGO/Virgo/KAGRA S250201i: Coverage and upper limits from MAXI/GSC observations
- EP250108A / SN 2025kg: Upper limits from a neutrino search with IceCube
- GRB 250128B: VLA possible radio detection
- GRB 250127A: EP-FXT second observation epoch and confirmation of the x-ray afterglow fading
- GRB 250129A: Skynet optical observations
- GRB 250129A: Swift-XRT refined Analysis
- The EP-WXT trigger 01709131085: KAIT confirmation of the stellar flare
- GRB 250128B: VLT/FORS2 optical observations
- GRB 250128B: Swift-XRT refined Analysis
- Swift GRB 250128B: Global MASTER-Net observations report
- EP250125a: Upper limits from Swift/BAT-GUANO
- GRB 250128B: Swift detection of a short burst
- GRB 250127B: DDOTI Upper Limit on the Afterglow
- Fermi-LAT Gamma-ray Observations of IceCube-250102A
- GRB 250127A: EP-FXT afterglow detection
- GRB 250117A: Fermi GBM Observation
- Fermi GRB 250127B: Global MASTER-Net observations report
- Fermi-LAT Gamma-ray Observations of IceCube-250101A
- GRB 250126A: MAXI/GSC detection
- EP250108a / SN 2025kg: Refined Analysis of EP-WXT Detection
- EP250125a: a new X-ray transient detected by Einstein Probe
- Konus-Wind detection of a bright burst from SGR 1E1841-045 on 2025 January 23
- GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
- IPN triangulation of a bright burst from SGR 1E1841-045
- EP250108a: AbAO, CMO and Terskol optical upper limits
- Konus-Wind detection of GRB 250118B
- GRB 250121A: Fermi GBM Observation
- IPN triangulation of GRB 250118B
- Konus-Wind detection of GRB 250119B
- IPN triangulation of GRB 250119B
- GRB 250121A: Fermi-LAT detection
- LIGO/Virgo S250119cv: Swift XRT observations, 5 X-ray sources
- GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
- GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
- Fermi-LAT Gamma-ray Observations of IceCube-241224A
- GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
- Konus-Wind detection of GRB 250117A
- IPN triangulation of GRB 250117A (short)
- LIGO/Virgo/KAGRA S250119cv: Updated NED Galaxies in the Localization Volume