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"- GRB 140318A: WHT spectroscopy
- GRB 140318A: NOT detection of the afterglow
- GRB 140318A: Swift detection of a burst
- GRB 140311A: VLA Detection
- GRB140308A: Suzaku WAM observation of the prompt emission
- GRB 140311C: MASTER optical observations
- GRB 140311C: Swift-XRT and UVOT observations
- GRB 140311C: MASTER before, during and after trigger optical observations
- GRB 140311A: further NOT observations
- GRB 140311B: Swift-BAT refined analysis
- GRB 140311A: RATIR Optical and NIR Detection
- GRB 140311C: Fermi GBM Detection
- GRB 140311A: Montarrenti Observatory optical upper limit
- GRB 140311B: Fermi GBM Detection
- GRB 140311A: Kottamia I-band observation
- GRB 140311A: Swift/UVOT Upper Limits
- GRB 140311B: Swift/UVOT Upper Limits
- Fermi416242156: possible iPTF counterpart
- GRB 140311B: RATIR Optical and NIR Observations
- GRB 140311A: Bassano Bresciano Observatory optical upper limit
- GRB 140311A: Swift-XRT refined Analysis
- GRO J1744-28: Fermi GBM observation
- GRB 140311A: Gemini-North redshift
- GRB 140302A: GROND confirmation of the afterglow
- GRB 140311A: NOT redshift confirmation
- GRB 140311B: Swift-XRT refined Analysis
- GRB 140311A: Swift-BAT refined analysis
- GRB 140311A: Gemini-South redshift
- GRB 140311B: final MASTER OT light curve
- GRB 140311A: Enhanced Swift-XRT position
- GRB 140311B: Enhanced Swift-XRT position
- GRB 140311A: Recalibration of photometry of OT detected with Kottamia 188cm telescope
- GRB 140311A: Nanshan afterglow decay
- GRB 140311B: TAROT Calern observatory optical observations
- GRB 140311A: Optical follow-up observation with Kottamia 188cm telescope
- GRB 140311A: NOT observations of the optical afterglow
- GRB 140311A: Zadko observatory - Gingin optical observations
- GRB140311B: Swift/XRT position
- GRB 140311B: Swift-XRT observations
- GRB 140311B: Nanshan afterglow detection
- GRB 140311B: MASTER early optical observations
- GRB 140311A: Nanshan OT detection
- GRB 140311A: MASTER early optical observations
- GRB 140311B: Swift detection of a burst
- GRB 140311A: Swift detection of a probable burst
- Konus-Wind observation of GRB 140308A
- GRB 140304A: Suzaku WAM observation of the prompt emission
- IPN Triangulation of GRB 140308A
- GRB 140306A: Suzaku WAM observation of the prompt emission
- 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