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"35348 results found.
- GBR 070419A: Swift/XRT refined analysis
- GRB 070420: TAROT La Silla observatory optical observations
- GRB 070420: NIR and optical afterglow confirmed
- GRB 070420: Swift detection of a burst with optical afterglow
- GRB 070419A: MITSuME Okayama Observations
- GRB 070419A: Early Super-LOTIS Observations
- GRB 070419B, Swift-BAT refined analysis
- GRB 070419A Swift-BAT Refined Analysis
- GRB 070419A: RAPTOR Detection of Early Emission
- GRB 070419B: Swift XRT refined analysis
- GRB 070419: Keck/LRIS Absorption Redshift
- GRB 070419B: optical afterglow confirmation
- GRB 070419A, Optical observations
- GRB 070411: Deep VLT detection
- GRB070419 - SDSS Pre-Burst Observations
- GRB 070419A: SARA observations
- GRB 070419A: NAYUTA Optical Observation
- GRB 070419A: Faulkes Telescope North Optical Observations
- GRB 070419B optical afterglow candidate
- GRB 070419A: Optical and IR observations with KANATA
- GRB 070419B: optical afterglow candidate
- GRB 070419A: Lulin Optical observation
- Infrared detection of GRB070419A with UKIRT
- GRB 070419A: Kiso Optical observation
- GRB070330: Correction to UVOT position
- GRB 070419: P60 Confirmation of Optical Afterglow
- GRB 070419B: Swift detection of a burst
- GRB 070419 optical afterglow candidate
- GRB 070419A: ROTSE-III Optical Limits
- GRB 070419: Swift detection of a burst
- Swift-BAT Trigger 276045 is a Cosmic Ray Shower event
- GRB 070418: Optical and IR observations with KANATA
- Trigger 276045: Swift detection of a possible burst
- GRB 070406: Swift XRT refined analysis
- IBAS Alert n.4202: not a real GRB
- GRB 070318, SMARTS optical/IR afterglow observations
- GRB 070411: TLS data shows plateau, flares
- GRB070412: UKIRT-WFCAM JHK upper limits
- GRB070412: Swift UVOT observations
- IBAS Alert n.4199: Not a GRB
- GRB 070411: Swift/UVOT observations
- GRB 070412, Swift-BAT refined analysis
- GRB 070412 Liverpool Telescope optical limit
- GRB 070411: Optical photometry at Crni Vrh
- GRB 070412: Swift-XRT refined analysis
- GRB 070411: Swift-XRT refined analysis
- GRB 070412: further reanalysis of NOT images
- GRB 070412: Optical observations at Crni Vrh
- GRB 070411: OA redshift
- GRB 070412: Swift-XRT refined position
- GRB 070412: further NOT observations
- GRB 070412: Gemini/GMOS afterglow candidate
- GRB 070412: IAC80 optical afterglow candidate
- GRB 070411: Magellan/Clay photometry
- GRB 070411: Magellan/IMACS photometry
- GRB 070412: NOT observations
- GRB 070412: Nearby bright galaxy
- GRB 070411, Swift-BAT refined analysis
- GRB 070412: Swift detection of a burst
- GRB 070411: IAC80 optical observations
- GRB 070411 : Liverpool Telescope Observations
- GRB 070411: Optical observations at Crni Vrh
- GRB 070411: ROTSE-III Detection of Optical Counterpart
- GRB 070411: Tautenburg RRM Afterglow Confirmation
- GRB 070411: Swift detection of a burst with optical afterglow
- GRB 070406: "Star" in XRT error circle S2 is an AGN?
- GRB 070406: Swift XRT team further analysis
- GRB 070406: Astrometrically Refined XRT Position, Unfading Source
- GRB 070406: Bright galaxy in XRT error circle is a quasar
- GRB 070406, Swift-BAT refined analysis
- GRB 070406: Correction to the optical candidate in GCN6253
- GRB 070406: Gemini South Imaging and XRT analysis
- GRB070406: Swift UVOT observations
- GRB 070406: further analysis of NOT images.
- Short GRB 070406 - Possible Bright Host Galaxy
- GRB 070406: Swift XRT Team analysis - Possible X-ray counterpart
- GRB 070406: NOT observations
- GRB 070406: Optical candidate
- GRB 070406: The exprosure time of Xinglong TNT optical Upper Limit
- GRB 070406: SARA upper limit
- GRB 070406: Xinglong TNT optical Upper Limit
- GRB 070406: photo-z of a bright galaxy in BAT error circle
- GRB 070406: Swift detection of a burst
- GRB 070402: Suzaku WAM observation of the prompt emission
- GRB 070311, deep optical photometry
- GRB 070402: pseudo-z~3.36 from spectral parameters of the prompt
- Konus-Wind and Konus-A observations of GRB 070402
- IPN triangulation of GRB070402
- GRB 070328: Suzaku WAM observation of the prompt emission
- GRB 070330, Swift-BAT refined analysis
- GRB 070330, SMARTS optical/IR observations
- GRB 070330: TAROT La Silla observatory optical observations
- GRB 070330: Swift-XRT refined analysis
- GRB 070330 - Watcher Observations
- GRB 070330: Swift detection of a burst
- GRB 070328: pseudo-z~2.75 from spectral parameters of the prompt
- Konus-Wind observation of GRB 070328
- GRB 070328: Swift/UVOT Upper Limits
- long burst from SGR 1806-20 detected on March 26
- GRB 070328: Swift/XRT Refined Analysis