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"
6094 results found.
- GRB 241030A: SAO RAS optical observations
- GRB 241030A: Fermi GBM Observation
- EP241030a: EP detection of GRB 241030A X-ray Afterglow
- GRB241030B: Fermi GBM Observation
- GRB 241029A: SVOM/VT optical afterglow observations
- EP241021a: Swift-UVOT detection
- GRB 241030A: Swift-XRT refined Analysis
- GRB 241030B: SAO RAS optical observations
- Konus-Wind detection of GRB 241030A
- GRB 241030A: Fermi-LAT detection
- EP 241021a: further Swift-XRT observations and X-ray counterpart detection
- GRB 241029A: SAO RAS optical observations
- EP241021a: SAO RAS observations of rebrightening
- GRB 241029A: Swift-XRT observations
- GRB 241029A: Fermi GBM Observation
- Konus-Wind detection of GRB 241025A
- GRB 241025A: further SAO RAS optical observations
- GRB 241026A: BTA and Zeiss-1000 optical observations
- GRB 241026A Fermi GBM Analysis
- GRB 241025A: SAO RAS optical observations
- EP241021a: further SAO RAS optical observations
- GRB 241026A: Swift-XRT refined Analysis
- GRB241025A: 1.3m DFOT optical afterglow detection
- GRB 241025A: optical photometry from Konkoly
- GRB 241025A: Swift-XRT refined Analysis
- GRB 241025C: Fermi GBM Detection
- GRB 241025A: Fermi GBM Observation
- EP 241021a: Swift-XRT observations
- EP241025a (GRB 241025A): EP observations update
- EP241021a: No Detection in Fermi-GBM Observation
- EP241021a: SAO RAS optical observations
- EP241021a: 1.3m DFOT Optical observations
- EP241021a: Optical upper limits with Kinder observations
- EP241021a: TRT optical observations
- EP241021a: NOT likely optical counterpart
- GRB241017A: 1.3m DFOT optical upper limit
- GRB 241018A: 1.3m DFOT Optical upper limit
- GRB241018A: XingLong Optical Upper Limit
- GRB 241018A: Swift-XRT observations
- GRB 241016B: Fermi GBM Observations
- GRB 241017A: Swift-XRT observations
- GRB 241001A: EP-FXT afterglow detection
- GRB 241013B: Fermi GBM Observation
- GRB 241013A: Fermi GBM Observation
- GRB 241009A: Swift-XRT afterglow detection
- GRB 241010A: JinShan optical observations and potential host galaxy
- GRB 241010A: Swift-XRT refined Analysis
- Fermi-LAT Gamma-ray Observations of IceCube-241006A
- GRB 241008A: Fermi GBM Observation
- GRB 241008A: Fermi-LAT detection
- GRB 241002B: Swift-XRT afterglow detection
- Fermi-LAT Gamma-ray Observations of NuEm-240926A
- GRB 241006A: Swift-XRT refined Analysis
- GRB 241001A: Swift-XRT afterglow detection
- GRB 241002B: Fermi GBM Observation
- GRB 241002B: Swift-XRT observations
- GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
- GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
- NuEm-240926A: Upper limits from a search for coincident neutrino events in IceCube
- GRB 241002A: Swift-XRT refined Analysis
- GRB 241001A: Swift-XRT observations
- GRB 240930B: Fermi GBM Observation
- Fermi-LAT Gamma-ray Observations of IceCube-240929A
- Konus-Wind detection of GRB 240912A
- EP240919a / GRB 240919A: SVOM/VT upper limit
- LIGO/Virgo S240919bn: Swift XRT observations, 10 X-ray sources
- EP240918b and EP240918c: Optical upper limits with Kinder observations
- EP240919a: Optical upper limit with Kinder observations
- GRB 240919A / EP240919a: SVOM/GRM observation
- GRB 240910A: further Swift observations and confirmation of afterglow
- EP240918a: Optical upper limits with Kinder observations
- GRB 240916A: NOT optical observation
- GRB 240916A: Fermi GBM Observation
- GRB 240916A: Swift-XRT afterglow detection
- LIGO/Virgo S240915b: Swift XRT observations, 8 X-ray sources
- EP240913a: VLT/HAWK-I near-infrared upper limits
- GRB 240913C: Fermi GBM detection
- GRB 240914A: Swift-XRT observations
- GRB 240910A: SVOM/VT optical observations
- EP240913a: NOT optical upper limits
- EP240913a: Swift/XRT detection of an X-ray source within the EP/WXT error circle
- GRB 240905E: further NOT optical observations
- GRB 240911A: Swift-XRT observations
- GRB 240912A: Swift-XRT refined Analysis
- GRB 240912A: Fermi GBM Observation
- GRB 240910A: Fermi GBM Observation
- GRB 240910A: NOT optical observations
- GRB 240910A: Swift-XRT detection of GOTO24fvl/AT2024vfp
- GRB 240910A: JinShan optical observations
- GRB 240825A: 7DT Optical Upper Limit
- GRB 240905E: SVOM/VT optical observations
- GRB 240910A: SVOM/GRM observation
- GRB 240905B: Fermi GBM Observation
- EP240908a: TRT optical upper limit
- EP240908a: EP detection of a fast X-ray transient
- GRB 240905B: Swift-XRT observations
- GRB 240905B: Fermi-LAT detection
- GRB 240905E: NOT optical upper limits
- GRB 240905E: Swift-XRT refined Analysis
- GRB 240905E: SAO RAS optical upper limit