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"23711 results found.
- EP240506a: EP-WXT detection of a new fast X-ray transient
- LIGO/Virgo/KAGRA S240507p: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240422ed: Additional WINTER near-infrared J-band observations
- LIGO/Virgo/KAGRA S240422ed: Swope Follow-up of AT2024hfr and AT2024hfs
- Fermi trigger No 736564880: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240505av: Identification of a GW compact binary merger candidate
- IceCube-240424A: GRANDMA Optical Upper Limit of Fermi J2151.3+0220
- Fermi trigger No 736461232: Global MASTER-Net observations report
- Fermi GRB 240504A: Global MASTER-Net observations report
- Fermi trigger No 736472503: Global MASTER-Net observations report
- GRB 240503A: AstroSat CZTI detection
- Fermi trigger No 736387941: Global MASTER-Net observations report
- GRB 240502A: GOTO optical upper limit
- Fermi trigger No 736379109: Global MASTER-Net observations report
- GRB 240502C: GOTO possible optical counterpart candidates
- Fermi GRB 240502B: Global MASTER-Net observations report
- Fermi GRB 240502A: Global MASTER-Net observations report
- GRB 240501B: GRBAlpha detection
- GRB 240430A: GRBAlpha detection
- LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet Transient Candidates
- Integral GRB240502.23: Global MASTER-Net observations report
- Fermi GRB 240501A: Global MASTER-Net observations report
- Fermi trigger No 736197684: Global MASTER-Net observations report
- GRB 240426A: VZLUSAT-2 detection
- GRB 240425A: VZLUSAT-2 detection
- GRB 240501B: AstroSat CZTI detection
- GRB 240408B: VZLUSAT-2 detection
- GRB 240407A: VZLUSAT-2 detection
- LIGO/Virgo/KAGRA S240501an: Identification of a GW compact binary merger candidate
- GRB 240425A: GRBAlpha detection
- LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet ToO observations
- Fermi GRB 240428A: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240422ed: DDOTI Optical Upper Limit for J-GEM24a
- LIGO/Virgo/KAGRA S240422ed: Observations with 1.6m Mephisto
- LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
- LIGO/Virgo/KAGRA S240422ed: NOT optical observations of EP240426a
- EP240426b: EP-WXT detection of a new fast X-ray transient
- LIGO/Virgo/KAGRA S240422ed: Swope Follow-up of AT2024hfq, AT2024hfr, AT2024hfs, and AT2024hfx
- LIGO/Virgo/KAGRA S240422ed: BOOTES-6/DPRT optical upper limits for EP240426a
- LIGO/Virgo/KAGRA S240422ed: GRANDMA Optical Upper Limits for EP240426a
- GRB 240426A: AstroSat CZTI detection
- LIGO/Virgo/KAGRA S240422ed: BOOTES-4/MET Optical Upper Limits for EP240426a
- LIGO/Virgo/KAGRA S240422ed: EP-FXT Detection of the Potential Opitcal Electromagnetic Counterpart AT 2024hfq Reported by DECam
- GRB 240414A: NOEMA detection
- LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
- EP240426a: GMG optical upper limit
- LVK S240422ed: Further Swift-XRT followup of three sources
- LIGO/Virgo/KAGRA S240422ed: EP-FXT detection of a candidate counterpart EP240426a
- LIGO/Virgo/KAGRA S240426s: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240422ed: Magellan Follow-up Observations of Swift/XRT candidates
- LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility contuinued observations of S240422ed and candidate analysis
- LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search update and AT2024hfx, AT2024hgl observations
- LIGO/Virgo/KAGRA S240422ed: Second night Pan-STARRS observations of the skymap
- LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
- LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-FXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
- LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA and Kilonova-Catcher galaxy targeting observations
- LIGO/Virgo/KAGRA S240422ed: Magellan Spectrum of GW-MMADS Candidate AT2024hdo Indicates a Type II SN
- 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 S240422ed: Archival BlackGEM/MeerLICHT detections of AT 2024hdr & AT 2024hdq
- LIGO/Virgo/KAGRA S240422ed: No significant counterpart candidates in HAWC observations
- LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
- LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
- 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: Potential Magellan candidates from GCN 36263 are unrelated.
- LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Three Potential Electromagnetic Counterparts Reported So Far
- 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: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
- LIGO/Virgo/KAGRA S240422ed: Potential Candidates from Magellan galaxy-based search
- LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from Pan-STARRS observations of the skymap
- 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
- LXT240402A/GRB240402B: Chandra X-ray detection
- LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from ATLAS observations
- LIGO/Virgo/KAGRA S240422ed: WINTER near-infrared J-band observations
- 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 S240421ar: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240422ed: Coverage and upper limits from MAXI/GSC observations
- 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
- GRB 240421A: Glowbug gamma-ray detection
- GRB 240414A: radio detection with the VLA
- GRB 240414A: LBT optical detection
- GRB 240419B : MITSuME Akeno optical upper limits
- GRB 240415B: Swift-XRT observations
- Fermi GRB 240422A: Global MASTER-Net observations report
- Fermi GRB 240421B: Global MASTER-Net observations report
- Swift GRB 240421B: Global MASTER-Net observations report
- GRB 240421B: Fermi GBM Observation