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 130215A: Detection of the SN with the 10.4m GTC
- GRB130313A: Optical observations from GTC
- GRB 130313A: NOT optical upper limit
- GRB 130313A: Swift-XRT refined Analysis
- GRB 130313A: simultaneous and follow-up optical observations at BOOTES-3 and BOOTES-4
- GRB 130313A: Weihai optical upper limit
- GRB 130313A: Swift-XRT detection of a possible X-ray afterglow
- GRB 130313A: Swift-BAT refined analysis
- GRB 130313A: Zadko observatory - Gingin optical observations
- GRB 130313A: MASTER-Net optical observations
- GRB 130313A: Swift detection of a short burst
- IPN Triangulation of GRB 130307A
- GRB 100424A: Keck host detection and VLT/X-shooter redshift
- Swift XRT RETRACTION of GRB 130310A afterglow detection
- GRB 130310A: optical observations
- Swift XRT observations of GRB 130310A
- GRB 130306A: Swift Detection of a Possible Afterglow
- GRB 130131B: host detection and redshift
- Konus-Wind observation of GRB 130310A
- IPN triangulation of GRB 130310A
- GRB 130310A: Fermi GBM detection
- GRB 130310A: Fermi-LAT detection and localization
- GRB 130131A: JCMT SCUBA-2 sub-mm observations
- GRB 130306A: MITSuME Ishigakijima upper limits
- GRB 130306A: Swift-BAT refined analysis
- IPN triangulation of GRB 130228A
- GRB 130305A BAT refined circular
- GRB 130305A: Further Swift-XRT Observations
- Konus-Wind observation of GRB 130306A
- GRB 130305A: Optical Observations
- GRB 111123A: Keck-I host detection and VLT/X-shooter redshift
- GRB 130305A: Gemini-North upper limit
- GRB 130307A: Fermi GBM detection
- GRB 130306A: Fermi GBM observation
- GRB 130306A: MASTER-Net pre-Swift alert observation
- GRB 130305A: Swift/UVOT Upper Limit
- GRB 130305A: RATIR Observations
- GRB 130306A: Swift detection of a burst
- GRB 130305A: P60 Observations
- GRB 100615A: HST host detection and X-shooter redshift
- GRB 130305A: Swift/XRT detection of the afterglow
- Konus-Wind observation of GRB 130305A
- GRB 130305A: Fermi GBM observation
- GRB 130305A: Fermi LAT Detection
- Fermi GBM trigger 130301.638 is not GRB
- GBM trigger 383712005 (GRB 130228A?) : Possible high-energy photon emission in Fermi/LAT data
- GRB 130305A found in ground analysis of Swift/BAT data
- GRB 121128A: optical observations in Mondy observatory
- GRB 121128A: optical upper limit in Maidanak observatory
- GRB 130216A: Swift/UVOT Upper Limit
- GRB 130219A: Suzaku WAM observation of the prompt emission
- SGR 1806-20 outburst (trigger 549841), Swift-BAT refined analysis
- Trigger 549841: Swift detection of SGR1806-20
- Konus-Wind observation of GRB 130219A
- GRB 130216B: Suzaku WAM observation of the prompt emission
- GRB 130216A: possible radio counterpart is steady field source
- GRB 130216A: Swift/XRT observations
- IPN Triangulation of GRB 130219A
- GRB 130215A: Suzaku WAM observation of the prompt emission
- GRB 130215A: PTF P48 optical detection
- GRB 130219A: Fermi GBM detection
- GRB 130216B: Swift/XRT observations
- GRB 130216A: Further Swift-BAT refined analysis
- GRB 130216B: MASTER-Net early observation
- GRB 130216A: MASTER-Net early observations
- GRB 130215A: Continued RATIR Optical and NIR Monitoring
- GRB 130216A: Fermi GBM observation
- GRB 130216B: Fermi GBM observation
- GRB 130216A: possible early detection at 15 GHz
- GRB 130216A: MITSuME Ishigakijima upper limits
- GRB 130216B BAT refined analysis
- GRB 130216B: P200 NIR Observations
- GRB 130216A: P200 NIR Observations
- GRB 130216A: Swift-BAT refined analysis
- GRB 130216A: TAROT La Silla observatory optical observations
- GRB 130215A: Additional P200 NIR observations
- GRB 130216B: Burst found in ground analysis of BAT data
- GRB 120118B: host observations and redshift determination
- GRB 130216A: OSN I-band observations
- GRB 130216A: Swift detection of a burst
- GRB 130215A: P200 NIR observations
- GRB 130215A: GROND Detection of the Optical/NIR Afterglow
- GRB 130215A: MITSuME Okayama Optical Observation
- GRB 130215A: Fermi GBM detection
- GRB 130215A: RAPTOR Measurements
- GRB 130215A: GMG optical observation
- GRB 130215A: iTelescope T11 observations
- GRB 130215A: Xinglong optical observations
- GRB 130215A: Swift-BAT refined analysis
- GRB 130215A: TAROT La Silla observatory optical observations
- GRB 130215A: RATIR Optical and NIR Observations
- GRB 130215A: REM NIR observations
- GRB 130215A: CARMA 3mm detection
- GRB 130215A: P60 Observations
- GRB 130215A: ROTSE-III data analysis
- GRB 130215A: Redshift estimate
- Skynet Observations of GRB130215
- GRB 130215: ROTSE-III Detection of Optical Counterpart
- GRB 130215A: Swift detection of a burst
- Swift GRB130206A: late XRT observations.