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"19533 results found.
- GRB 121031A: Prompt enhanced Swift-XRT position
- GRB 121031A: Swift detection of a burst
- Swift Quick-look and HEASARC are back online
- GRB 121027A: Swift/UVOT Possible Detection
- GRB 121028A: near-IR observations at Calar Alto
- GRB 121028A: RAPTOR Limits During Gamma-Ray Emitting Interval
- Swift Quick-look and HEASARC will be offline for due to hurricane Sandy
- GRB 121027A: MASTER early prompt optical limit
- GRB 121027A: Swift-XRT refined Analysis
- GRB 121027A: Brightening IR counterpart
- GRB 121028A: Swift-XRT refined Analysis
- GRB 121028A: Enhanced Swift-XRT position
- GRB 121028A: Swift-BAT refined analysis
- GRB 121027A: Enhanced Swift-XRT position
- GRB 121028A: Swift detection of a burst
- GRB 121011A: optical observations
- GRB 121027A: nIR afterglow candidate with AAT
- GRB 121027A: Swift-BAT refined analysis
- GRB 121025A: Swift-XRT observation
- GRB 121027A: MAXI/GSC detection 40 minutes after the Swift Trigger
- GRB 121027A: Swift detection of a burst
- Swift Quick-look and HEASARC will be offline for 24 hours this weekend
- Swift-BAT trigger 536502 is not astrophysical
- GRB 121024A: Swift/UVOT Observations
- GRB 121024A: Swift-BAT refined analysis
- GRB 121024A: Enhanced Swift-XRT position
- GRB 121024A: PAIRITEL NIR Detection
- GRB 121024A: Swift-XRT refined Analysis
- GRB 121024A: GROND Detection of the Optical/NIR Afterglow
- Skynet PROMPT/Dolomiti observations of GRB121024A
- GRB 121024A: TAROT Calern observatory optical detection of a bright counterpart
- GRB 121024A: Swift detection of a burst with an optical counterpart
- Swift Trigger 536502 is likely a noise fluctuation in coincidence with SAX J1818.6-1703
- GRB 121011A: early optical light curve
- GRB 121017A: Swift/UVOT Upper Limits
- GRB 121017A: Swift-XRT refined Analysis
- GRB 121017A: GROND Observations
- GRB 121017A: Swift-BAT refined analysis
- GRB 121017A: Enhanced Swift-XRT position
- GRB 121017A: 1.23m CAHA R-band observations
- GRB 121017A: BOOTES-2/TELMA observations
- GRB 121017A: Swift detection of a burst
- GRB 121011A Suzaku WAM observation of the prompt emission
- GRB 121014A: Swift-BAT refined analysis
- GRB 121014A: Swift detection of a burst
- GRB 121011A: Swift/UVOT Detection
- GRB 121011A: Fermi GBM observation
- GRB 121011A: Fermi-LAT detection of a burst
- Swift-BAT trigger 535733 is not astrophysical
- GRB 121011A: Swift-XRT refined Analysis
- GRB 121011A: optical observations
- GRB 121011A, Swift-BAT refined analysis
- Swift-BAT refined analysis of the SGR 1806-20 outburst (trigger 535747)
- GRB 121011A: Enhanced Swift-XRT position
- GRB 121011A: MASTER-Net early OT light curve
- GRB 121011A: Swift detection of a burst with optical afterglow
- Trigger 535747: Swift detection of an outburst from SGR1806-20
- Trigger 535733: Swift possible detection of SAX J1828.5-1037
- GRB 120927A: optical upper limit
- GRB 120804A: Late-time Chandra observation
- GRB 121001A: GROND Afterglow Confirmation
- GRB 121001A: Swift/UVOT Upper Limits
- GRB 121001A: Swift-XRT refined Analysis
- GRB 121001A: Enhanced Swift-XRT Position
- Swift Trigger 535026 is GRB 121001A: Swift-BAT refined analysis
- Swift Trigger 535026: Optical decay confirmation with IAC80 and BOOTES-2/TELMA.
- GRB 121001A: MASTER optical observations
- GRB 121001A: possible optical counterpart
- Swift Trigger 535026: ROTSE-III Optical Limits
- Swift Trigger 535026: Galactic Transient or possible GRB
- GRB 120927A: Swift/UVOT Upper Limits
- GRB 120927A, Swift-BAT refined analysis
- GRB 120927A: GROND upper limits
- GRB 120927A: Swift-XRT refined Analysis
- GRB 120927A: Enhanced Swift-XRT position
- GRB 120927A: Swift detection of a burst
- Further Swift-XRT observations of the GRB 120919A field.
- GRB 120923A: optical upper limit
- GRB 120923A: RAPTOR Early Afterglow Limits
- GRB 120916A Suzaku WAM observation of the prompt emission
- GRB 120923A: RAPTOR Limits During Gamma-Ray Emitting Interval
- GRB 120923A: CARMA Observations
- GRB 120923A: EVLA Observations
- GRB 120923A: Swift-XRT refined Analysis
- GRB 120923A: GROND Upper limits
- GRB 120922A: Fermi GBM detection
- GRB 120922A: Swift/UVOT Detection
- GRB 120923A: Swift-BAT refined analysis
- GRB 120922A: Swift-BAT refined analysis
- GRB 120923A: Swift/UVOT Upper Limit
- GRB 120922A: Swift-XRT refined Analysis
- GRB 120922A: Swift/UVOT Observations
- GRB 120923A: Enhanced Swift-XRT position
- GRB 120922A: Enhanced Swift-XRT position
- GRB 120922A: TAROT La Silla observatory optical observations
- GRB 120923A: TAROT La Silla observatory optical observations
- GRB 120923A: ROTSE-III Optical Limits
- GRB 120923A: Swift detection of a burst
- GRB 120922A: GROND afterglow candidate
- GRB 120922A: Prompt enhanced Swift-XRT position