GCN Circulars
GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"24519 results found.
- GRB 240425A: Fermi GBM Final Real-time Localization
- Fermi trigger No 735697285: Global MASTER-Net observations report
- GRB 240419B: Swift-BAT refined analysis
- GRB 240421B: Swift-BAT refined analysis
- GRB 240422A: Glowbug gamma-ray detection
- LIGO/Virgo/KAGRA S240413p: DESGW DECam Follow-Up
- LIGO/Virgo/KAGRA S240422ed: No significant counterpart candidates in HAWC observations
- LIGO/Virgo/KAGRA S240422ed: Vetting of DECam Candidates Using Real-Time Resources and SAGUARO Infrastructure
- LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
- IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
- LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
- LIGO/Virgo/KAGRA S240422ed: Early X-ray Upper Limits from EP-WXT for the LVK Sky Localization Region
- LIGO/Virgo/KAGRA S240422ed: Continued Imaging of Mag24a
- LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
- GRB 240421B: GRBAlpha detection
- IceCube Alert 240424.08: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240422ed: Magellan Detection of a Potential Electromagnetic Counterpart
- LIGO/Virgo/KAGRA S240422ed: SAGUARO upper limits from CSS
- LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
- LIGO/Virgo/KAGRA S240422ed: Potential Candidates from Magellan galaxy-based search
- IceCube-240419A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S240421ar: Updated Sky localization
- LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam upper limits on the Swift/XRT source S240422ed_X61
- LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search
- LIGO/Virgo/KAGRA S240422ed: No Counterparts in DDOTI/OAN Optical Observations
- GRB 240419A: Swift-BAT refined analysis
- GRB 240418A: Swift-BAT refined analysis
- LIGO/Virgo/KAGRA S240422ed: WINTER near-infrared J-band observations
- LIGO/Virgo S240422ed: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility observations and candidates
- LIGO/Virgo/KAGRA S240422ed: Magellan Observations
- LIGO/Virgo/KAGRA S240422ed: Updated NED Galaxies in the Localization Volume
- LIGO/Virgo/KAGRA S240422ed: AstroSat CZTI non-detection and upper limits
- LIGO/Virgo/KAGRA S240422ed: Upper limits from Fermi-GBM Observations
- LIGO/Virgo/KAGRA S240422ed: Updated Sky localization and EM Bright Classification
- LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240422ed: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S240422ed: Identification of a GW compact binary merger candidate
- LIGO/Virgo/Kagra S240422ed: NED Galaxies in the Localization Volume
- LIGO/Virgo/KAGRA S240422ed: Global MASTER-Net observations report
- Fermi trigger No 735470374: Global MASTER-Net observations report
- Fermi-LAT gamma-ray observations of IceCube-240419A
- GRB 240419B : MITSuME Akeno optical upper limits
- GRB 240415B: Swift-XRT observations
- Fermi GRB 240422A: Global MASTER-Net observations report
- GRB 240422A: Fermi GBM Final Real-time Localization
- Fermi GRB 240421B: Global MASTER-Net observations report
- Swift GRB 240421B: Global MASTER-Net observations report
- GRB 240421B: Fermi GBM Observation
- GRB 240421B: J-band upper limits from WINTER
- Fermi GRB 240421A: Global MASTER-Net observations report
- EP240417a: no counterpart detection by SOAR
- EP240420a: Xinglong decaying optical counterpart
- EP240420a: Nanshan optical counterpart observations
- LIGO/Virgo/KAGRA S240421ar: Identification of a GW unmodeled transient candidate
- GRB 240421A: Fermi GBM Final Real-time Localization
- EP240420a: detection of fading X-ray emission with refined position by EP-FXT
- EP240420a: NOT optical counterpart candidate and potential host
- Fermi trigger No 735280430: Global MASTER-Net observations report
- GRB240419A: Skynet Optical Afterglow Analysis
- GRB240418A - Candidate afterglow from NIRES
- IceCube Alert 240419.98: Global MASTER-Net observations report
- IceCube-240419A - IceCube observation of a high-energy neutrino candidate track-like event
- IceCube-240419A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 240419B: Swift-XRT refined Analysis
- GRB 240419B: optical afterglow from the NOT
- LIGO/Virgo/KAGRA S240420aw: Retraction of GW compact binary merger candidate
- Swift GRB 240419B: Global MASTER-Net observations report
- Swift GRB 240419A: Global MASTER-Net observations report
- GRB 240419A: REM NIR afterglow detection
- EP240417a: YAHPT Optical Upper Limits
- GRB240418A: YAHPT Upper Limits
- GRB 240419A: VLT optical afterglow detection
- Fermi trigger No 735089036: Global MASTER-Net observations report
- GRB 240418A: NOT optical upper limits
- GRB 240411A: GOTO early optical upper limits
- Swift GRB240418.85: Global MASTER-Net observations report
- GRB 240418A: Swift detection of a burst
- Fermi GRB 240417A: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240413p: X-ray upper limits from EP-WXT for the candidate AGN counterpart
- EP240416a: BOOTES-2/TELMA Optical Upper Limit
- IceCube-Cascade 240416A: Upper limits from a search for additional neutrino events in IceCube
- GRB 240417A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S240413p: historical ATLAS and ZTF observations of the candidate AGN counterpart
- GRB 240414A: Glowbug gamma-ray detection
- LIGO/Virgo/KAGRA S240413p: STEP - T80S Search and Candidate Counterpart Identification
- GRB 240415B: GECAM-B detection
- EP 240416a: Xinglong and NOT decaying optical counterpart
- GRB 240415A: Swift-BAT refined analysis
- EP240416A: MASTER optical observations
- GRB 240414A: Swift-BAT refined analysis
- EP240416a: Kinder optical counterpart candidate
- EP240413a: BOOTES-2/TELMA Optical Upper Limit
- GRB 240415A: Fermi GBM Observation
- GRB 240414A: GMG observation
- EP 240414a: BOOTES-4/MET Optical Upper Limits
- EP240414a: EP-FXT follow-up observation
- GRB 240415B: Swift/BAT-GUANO arcminute localization of a short burst
- GRB 240414A: Fermi GBM Observation
- Fermi GRB 240415A: Global MASTER-Net observations report