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"12390 results found.
- GRB 250925A: GROWTH-India Telescope Upper Limits
- Swift GRB 250925A: Global MASTER-Net observations report
- GRB 250924A: 1.6m Mephisto optical upper limits
- GRB 250924A: Swift/UVOT Detection
- GRB 250924A: GROWTH-India Telescope Upper Limits
- Swift GRB 250924A: Global MASTER-Net observations report
- GRB 250920B: AbAO optical upper limits
- Konus-Wind detection of GRB 250920C
- EP250911a: e-MERLIN radio observations
- Fermi GRB 250922B: Global MASTER-Net observations report
- GRB 250920C: NIR observations with WINTER
- GRB 250920B: NIR observations with WINTER
- Fermi trigger No 780156732: Global MASTER-Net observations report
- GRB 250916A: Swift/UVOT Detection
- GRB 250920B: Kitab-ISON optical upper limit
- GRB 250917B: KAIT optical upper limit
- GRB 250920C: Swift/UVOT Detection
- Swift GRB 250920C: Global MASTER-Net observations report
- GRB 250920B: Swift/UVOT Detection
- LIGO/Virgo/KAGRA S250920bq: Coverage and upper limits from MAXI/GSC observations
- Swift GRB 250920B: Global MASTER-Net observations report
- Fermi GRB 250918A: Global MASTER-Net observations report
- GRB 250919A: Swift-XRT afterglow detection
- EP250919a: Global MASTER-Net observations report
- Fermi GRB 250919A: Global MASTER-Net observations report
- GRB 250917B: Swift/UVOT Upper Limits
- GRB 250916A: Swift-XRT observations
- GRB 250917B: Swift-XRT observations
- Fermi GRB 250917B: Global MASTER-Net observations report
- GRB 250917B: Swift detection of a short burst
- GRB 250916A: GOTO optical counterpart candidate
- Fermi GRB 250916A: Global MASTER-Net observations report
- GRB 250912A: Swift-XRT observations
- GRB 250912A: VLT observations
- GRB 250912A:SVOM/VT optical upper limit
- GRB 250912A: LCO optical upper limit
- Fermi GRB 250912A: Global MASTER-Net observations report
- EP250911a: Global MASTER-Net observations report
- IceCube-Cascade 250911A: Upper limits from a search for additional neutrino events in IceCube
- EP250911a: Upper limit from Fermi-GBM Observations
- EP250911a: Swift-XRT observations
- GRB 250911A: Swift/UVOT Detection
- Fermi GRB 250910B: Global MASTER-Net observations report
- EP250910a: Global MASTER-Net observations report
- GRB 250910A: SVOM/VT optical upper limit
- GRB 250910A: LCO optical upper limit
- EP#01709240653: Swift-XRT observations
- EP250908c: Global MASTER-Net observations report
- Fermi GRB 250909A: Global MASTER-Net observations report
- Fermi-LAT Gamma-ray Observations of IceCube-250905A
- IceCube-250905A: Upper limits from a search for additional neutrino events in IceCube
- EP250905a: Liverpool Telescope i-band upper limits
- EP250905a: Liverpool Telescope observations
- EP250905b: Global MASTER-Net observations report
- IceCube Alert 250905.84: Global MASTER-Net observations report
- GRB 250905A: Swift/UVOT Upper Limits
- EP250905a: Global MASTER-Net observations report
- GRB250904A: Liverpool Telescope upper limits
- GRB 250904A: Swift/UVOT Detection
- GRB 250905A: KAIT optical upper limit
- Swift GRB250905.09: Global MASTER-Net observations report
- Swift GRB 250904A: Global MASTER-Net observations report
- IceCube-Cascade 250903A: Upper limits from a search for additional neutrino events in IceCube
- EP250827a and EP250827b: Upper limit from Fermi-GBM Observations
- GRB 250904A: Swift detection of a burst
- GRB 250903A: Swift-XRT observations
- EP250903a: Swift-XRT observations
- EP#01709201209: Swift-XRT observations
- EP-WXT trigger 01709201209: Liverpool Telescope upper limits
- GRB 250903A: VLT X-shooter spectroscopic redshift z = 1.590
- EP250903a: Global MASTER-Net observations report
- Fermi GRB 250902B: Global MASTER-Net observations report
- Fermi-LAT Gamma-ray Observations of IceCube-250831A
- GRB 250901A: Swift/UVOT Upper Limit
- IceCube-250831A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-Cascade 250828A: Upper limits from a search for additional neutrino events in IceCube
- GRB 250901A: Swift-XRT afterglow detection
- EP250901a: Swift-XRT observations
- GRB 250901A: LCO optical upper limit
- EP250827b: Swift observations of AT 2025wkm
- EP250827b: Contemporaneous detection of EP X-ray flare EP250827b and ZTF transient ZTF25abmpngy/AT2025wkm
- EP250901a: Mephisto optical upper limits
- EP250901a: Global MASTER-Net observations report
- EP250831a: Swift-XRT observations
- LIGO/Virgo/KAGRA S250831cc: Coverage and upper limits from MAXI/GSC observations
- IceCube Alert 250831.75: Global MASTER-Net observations report
- EP250831a: Global MASTER-Net observations report
- GRB 250831A: Swift-XRT counterpart detection
- GRB 250831A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- GRB 250831A: SVOM/VT upper limit with VHF data
- GRB 250830B: Swift-XRT observations
- EP250830a: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S250830bp: Coverage and upper limits from MAXI/GSC observations
- EP-WXT trigger 01709200994: Liverpool Telescope upper limits
- GRB 250830B: MAXI/GSC detection
- GRB 250830A / MAXI J0853+337: MAXI/GSC detection
- EP250821a: SOAR observations
- EP250828a: Liverpool Telescope upper limits
- Swift GRB 250828B: Global MASTER-Net observations report
- EP250828a: Global MASTER-Net observations report