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.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
- GRB 250115: A GRB during the coffee break at AAS
- GRB test from AAS
- GRB test
- GRB 000001Q TEST
- GRB 123456Z courey testing
- GRB Test
- GRB testing
- GRB iOS chrome again
- grb123: iOS Chrome testing
- GRB testing iOS
- GRB test from Chrome iOS
- GRB testing
- GRB Testing for Kafka
- GRB Testing
- GRB foobar
- GRB foobar test
- GRB testing 3
- GRB testing 2
- GRB testing
- GRB test 4
- GRB test 3
- GRB test 2
- GRB test
- GRB foobar
- GRB foobar
- LIGO/Virgo/KAGRA S230627c: Zwicky Transient Facility observations and candidates
- LIGO/Virgo/KAGRA S230627c: Zwicky Transient Facility observations and candidates
- GRB foobar
- GRB foobar
- PKS2326-505, millimeter wavelength flare, transient
- GRB foo 3
- GRB foo 2
- GRB foo
- GRB foo
- GRB foo
- GRB foo
- GRB test
- GRB foo
- GRB foobar
- GRB foobar
- GRB foobar
- GRB foobar
- GRB foobar
- GRB test
- MAGIC test
- GRB test
- GRB foo
- Test GCN GW submission
- GRB test 2
- GRB test
- GRB test
- Test GW GCN hermes submission 2
- Test GW GCN hermes submission
- Test GW GCN hermes submission
- A GRB test
- TEST GW GCN hermes submission
- GRB 170817A: an awesome GCN Circular
- VIRT optical transient detection
- GRB 230414B: 3.6m DOT Optical observations, slow decay at early epochs
- GRB 230307A: iTelescope optical upper limit (likely)
- GRB 230414B: Montarrenti Observatory late time optical afterglow detection
- IceCube-230416A: IceCube observation of a high-energy neutrino candidate
- Fermi trigger No 703284533: Global MASTER-Net observations report
- GRB 230414B: Lulin 40cm-SLT optical limit
- GRB 230414B: Bassano Bresciano Observatory optical observations
- GRB 230414B: Redshift from OSIRIS/GTC
- GRB 230414B: AbAO optical observations
- GRB 230409B: 3.6m DOT near-infrared detection, afterglow confirmation
- GRB 230414B: Swift-XRT refined Analysis
- GRB 230414B: Dabancheng/GHOST optical observations
- AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-230414A
- GRB 230414B: slow optical light curve decay
- GRB 230414B: SAO RAS optical observations
- GRB 230414B: Enhanced Swift-XRT position
- GRB 230414B: 1.3m DFOT Optical observations
- Fermi GRB 230414A: Global MASTER-Net observations report
- GRB 230414B: GROWTH India Telescope afterglow confirmation
- GRB 230414B (correction GRB name in the GCN 33615): Mondy optical afterglow candidate
- GRB 230414B: Nanshan/HMT optical afterglow detection
- GRB 230414A: Mondy optical afterglow candidate
- Swift GRB 230414B: Global MASTER-Net observations report
- GRB 230414B: Prompt enhanced Swift-XRT position
- GRB 230414B: Swift detection of a burst
- IceCube-230405A: BOOTES-4/MET Optical Upper Limits
- GRB 230414A: Fermi GBM Final Real-time Localization
- GRB 230328B: redshift lower limit estimating
- GRB 230409B: Mondy optical upper limit
- GRB 230409B: OHP/T193 optical upper limit
- GRB 230410B: VZLUSAT-2 detection
- GRB 230409D: VZLUSAT-2 detection
- GRB 230410B: AGILE detection of a burst
- GRB 230410A: Fermi GBM Final Real-time Localization
- Fermi GRB 230409C: Global MASTER-Net observations report
- Fermi GRB 230409A: Global MASTER-Net observations report
- GRB 230409C: Fermi GBM Final Real-time Localization
- GRB 230409B: Swift-XRT refined Analysis
- GRB 230409B: Swift-BAT refined analysis
- Fermi trigger No 702745263: Global MASTER-Net observations report
- Swift GRB 230409B: Global MASTER-Net observations report
- GRB 230409B: Swift/UVOT Detection