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"- Konus-Wind observation of GRB 140306A
- IPN Triangulation of GRB 140306A
- GRB 140304A: Continued RATIR Optical and NIR Observations
- GRB 140304A: 10.4m GTC refined redshift z = 5.283
- GRB 140306A: Fermi GBM detection
- GRB 140305A: Swift-BAT refined analysis
- Trigger 590503: Swift-BAT triggered on noise
- GRB 140304A: MASTER OT light curve
- GRB 140304A: CARMA 3mm detection
- GRB 140304A: VLA Detection
- GRB 140305A: Swift detection of a burst
- GRB 140304A: RATIR g-band Dropout
- GRB 140304A: Swift-BAT refined analysis
- GRB 140304A: Swift-XRT refined Analysis
- GRB 140304A: Enhanced Swift-XRT position
- GRB 140304A: Redshift from the NOT
- GRB 140304A: Fermi GBM detection
- GRB 140304A: 10.4m GTC redshift z = 5.39
- GRB 140304A: NOT observations and redshift estimate
- GRB 140304A: Swift/UVOT Upper Limits
- iPTF14yb: JVLA and CARMA observations
- GRB 140304A: Khureltogot optical observations
- GRB 140304A: Mondy optical observations
- GRB 140304A: Afterglow decay from Nanshan observations
- GRB 140304A: Swift detection of a burst
- GRB 140304A: MASTER OT detecton
- GRB 140301A: Swift/UVOT Upper Limits
- GRB 140302A: Swift/UVOT Upper Limits
- GRB 140302A: MITSuME Okayama upper limits
- GRB140302A: Fermi GBM detection
- GRB 140302A: Swift-XRT refined Analysis
- GRB 140302A: Swift-BAT refined analysis
- GRB 140302A: Enhanced Swift-XRT position
- GRB 140301A: Swift-BAT refined analysis
- GRB 140301A: Swift-XRT refined Analysis
- GRB 140301A: GROND Detection of the Optical/NIR Afterglow
- GRB 140302A: GROND afterglow candidate
- GRB 140302A: Prompt enhanced Swift-XRT position
- GRB 140302A: Swift detection of a burst
- GRB 140301A: VLT/X-shooter redshift
- GRB 140301A: NOT afterglow candidate
- GRB 140301A: Enhanced Swift-XRT position
- GRB 140301A: Skynet R-COP Observations
- GRB 140301A: Swift detection of a burst
- GRB 140226A/iPTF14yb: 1.23m CAHA observations
- GRB 140226A/iPTF14yb: Swift/UVOT Observations
- GRB 140226A/iPTF14yb: Mondy optical observations
- GRB 140226A/iPTF14yb: RATIR Optical and NIR Observations
- GRB 140226A / iPTF14yb: Swift-XRT confirms a fading X-ray source
- GRB 140219A: Mondy optical observations of XRT source #5
- Konus-Wind observation of GRB 140226A
- IPN triangulation of GRB 140226A, a possible GRB counterpart to iPTF14yb
- PTF14yb: GROND Transient Detection
- iPTF14yb: RATIR Optical and NIR Observations of the optical transient
- GRB 140219A: Suzaku WAM observation of the prompt emission
- iPTF14yb: Swift-XRT detection
- iPTF14yb: iPTF Discovery of an Optical Afterglow-like Transient
- GRB 140219A: MAXI/GSC detection
- GRB 140219A: the confirmation of the brightening SDSS J102406.41+062937.6 star
- GRB 140219A: Retraction of X-ray afterglow
- GRB 140219A: MASTER optical brightening inside XRT-5 error box detection
- GRB 140219A: iPTF optical observations
- GRB 140102A: TAOS early optical afterglow detection
- GRB 140219A: optical observations of XRT source #5
- GRB 140219A: XRT afterglow candidate
- GRB 140221A: Results from Swift XRT tiled observations
- GRB 140219A: Xuyi and Nanshan upper limits
- GRB 140219A: results from Swift XRT and UVOT tiled observations
- GRB 140219A: MASTER before and after GRB observational arguments of the exceptionally Dark GRB
- Konus-Wind observation of exceptionally bright GRB 140219A
- GRB 140221A Tiled Swift observations
- GRB 140221A: MAXI/GSC detection
- GRB 140219A: Fermi-LAT detection of a burst
- GRB 140219A: Fermi GBM Detection
- GRB 140219A Tiled Swift observations
- IPN Triangulation of extremely bright long GRB 140219A
- Swift follow-up of an Integral weak transient
- GRB 140213A: Continued Skynet R-COP/PROMPT Observations of the Optical Afterglow
- GRB 140215A: RAPTOR Observations During Gamma-Ray Emitting Interval
- Fermi GBM trigger 140214230 is not a GRB
- GRB 140213A: Continued Skynet R-COP/PROMPT Detections of a Rebrightening Optical Afterglow
- GRB 140215A: Continued Skynet PROMPT Observations of the Optical Afterglow
- GRB 140215A: WSRT radio observation
- GRB 140211A: Khureltogot optical upper limits
- GRB 140215A: Continued RATIR Optical and NIR Observations
- Konus-Wind observation of GRB 140213A
- Konus-Wind observation of GRB 140215A
- GRB 140215A: Swift/UVOT Detection
- GRB 140211A: Swift-XRT and UVOT observations
- GRB140215A: Continued Discovery Channel Telescope Observations
- GRB 140215A: Continued RATIR Optical and NIR Observations
- GRB 140215A: MITSuME Okayama Optical Observation
- GRB 140215A: Swift-BAT refined analysis
- GRB 140215A: ISON-NM optical observations
- GRB 140215A: Swift-XRT refined Analysis
- GRB 140215A: P60 observations
- GRB 140215A: T24 optical observations
- GRB 140215A: Enhanced Swift-XRT position
- GRB 140215A: RATIR Optical and NIR Observations
- GRB140215A: Skynet PROMPT Optical Observations