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').
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"7445 results found.
- GRB 150721A (Fermi GBM Trigger 459150552): iPTF P48 Observations
- GRB 150801B: Swift detection of a burst
- GRB 150801A: Tiled Swift observations
- GRB 150728A: TSHAO optical observations
- GRB 150728A: Swift detection of a GRB
- GRB 150727A: Watcher optical upper limit
- GRB 150727A: Swift detection of a burst with an optical counterpart
- GRB 150724B: Swift ToO observations
- Trigger 650221: Swift detection of a IGR J00291+5934
- GRB 150724A: Swift detection of a burst
- Swift Trigger 649706: a possible GRB or bright Galactic transient
- GRB 150716A: P60 Candidate Optical Afterglow
- GRB 150716A: RATIR Optical Observations
- GRB 150716A: Swift detection of a burst
- Trigger 649113: Swift detection of SGR 1E 1841-045
- GRB 150711A: Swift detection of a burst
- GRB 150710B: Swift ToO observations
- MASTER OT Detection during Fermi Trigger 458235025 inspection
- GRB 150710A: host galaxy for Swift XRT second candidate
- Swift trigger 648437: A GRB or a burst from 1RXS J125754.7+141850
- GRB 150702A: Swift ToO observations
- Swift Trigger 647642 is probably not an astrophysical source
- GRB 150627A: Swift ToO observations
- GRB 150626B: Swift detection of a burst
- GRB 150626A: Swift detection of a burst
- GRB 150622A: Tiled Swift observations
- Swift Trigger 645340: a possible GRB
- Konus-Wind observation of Galactic transient V404 Cyg in outburst
- GRB 150616A: Swift detection of a burst
- Optical follow-up of Swift trigger on V404 Cyg
- Swift trigger 643949 is V404 Cyg
- GRB 150615A: Swift detection of a burst
- Trigger 643078: Swift detection of H1743-322
- GRB 150608A: Tiled Swift observations
- GRB 150607A: Swift detection of a burst with an optical counterpart
- Swift Trigger 642453: a possible GRB
- GRB 150530B: Swift ToO observations
- GRB 150530A: Swift detection of a burst
- GRB 150527A: Swift detection of a burst
- GRB 150523A: Swift ToO observations
- GRB 150513A: request for X-ray follow up
- GRB 150523A: LCOGT FTS afterglow confirmation
- GRB 150523A: LCOGT Cerro-Tololo optical afterglow candidate
- GRB 150523B: Swift ToO observations
- Swift trigger 641332 is probably not an astrophysical source
- GRB 150518A: Mondy optical observations
- GRB 150518A: Tiled Swift observations
- GRB 150514A: Swift ToO observations
- GRB 150512A: iPTF Optical Observations
- Swift Trigger 639636: a possible GRB
- GRB 150428C: Tiled Swift observations
- GRB 150428A: GROND Dark Burst Host Candidate
- GRB 150428B: Swift detection of a burst
- GRB 150428A: Swift detection of a burst
- Trigger 639199: Swift detection of IGRJ16418-4532
- GRB 150424B: Tiled Swift observations
- GRB 150423A: WHT observations
- GRB 150424A: Swift detection of a short burst
- GRB 150423A: Keck optical afterglow confirmation
- GRB 150423A: GROND afterglow candidate
- GRB 150423A: Swift detection of a short burst
- Swift trigger 638589 is probably not an astrophysical source
- GRB 150418A: Tiled Swift observations
- Swift Trigger 638217 is probably not an astrophysical source
- GRB150413A, optical observations
- GRB 150407A: Swift ToO observations
- Swift triggered on a source in Terzan 5 (trigger=637212)
- Fermi trigger 449861706: MASTER-SAAO possible candidate to OT of Short GRB
- GRB 150403A: Swift detection of a burst with an optical counterpart
- GRB 150402A: results of Swift observations
- GRB 150402A: Swift ToO observations
- GRB 150323C: possible host galaxy detection
- GRB 150220A: Optical observations at Kyiv comet station
- GRB 150323C: Swift detection of a burst
- GRB 150323B: Swift ToO observations
- GRB 150323A: P60 Optical Afterglow Candidate
- GRB 150323A: Swift detection of a burst
- GRB 150318A: Swift detection of a burst
- GRB 150317A: Swift detection of a burst
- GRB 150314A: KAIT Optical Candidate
- GRB 150222A: CrAO optical observation
- GRB150309A: Optical observations at Crni Vrh
- GRB 150309A: Swift detection of a burst
- Swift J0045.2+4151: analysis of XMM-Newton archival data
- GRB 150302A: Mondy optical upper limit
- GRB 150302A: Swift/UVOT Upper Limits
- GRB 150302A: KAIT Optical Upper Limit
- GRB 150302A: UVOT Observations
- GRB 150302A: NOT afterglow candidate
- GRB 150302A: Swift detection of a burst
- GRB 150301B: GROND afterglow observations
- GRB 150301B: Swift detection of a burst with an optical afterglow
- Swift Trigger 633173 is probably not an astrophysical source
- GRB 150301A: Swift detection of a short burst or new SGR
- GRB 150220A: Swift ToO observations
- GRB 150222A: I-band observations from OSN
- GRB 150222A: GROND optical afterglow candidate
- GRB 150222A: Swift detection of a burst
- Swift detection of an outburst from SGR 1935+2154
- GRB 150219A: Swift ToO observations