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 110207A: MASTER prompt and early optical observations
- Konus-Wind observation of GRB 110205A
- GRB 110207A: Swift detection of a burst
- GRB 110206A: Swift detection of a probable X-ray afterglow
- GRB 110206A: TAROT La Silla observatory optical observations
- GRB 110205A: Lightbuckets Optical Observations
- GRB 110206A: a long GRB detected by INTEGRAL
- GRB 110205A : Lulin optical observation
- GRB110205A: MITSuME Ishigakijima Optical Observation
- GRB110205A: MITSuME Okayama Optical Observation
- GRB110205A: SMA 1.3mm Observations
- GRB 110205A: Swift/UVOT Continuing Observations
- GRB 110205A: Lulin optical observations and temporal decay index
- Observations GRB 110205A
- GRB 110205A: Swift-BAT refined analysis
- GRB 110205A: Newcastle Observatory Optical Observations
- GRB 110205A: Swift-XRT refined Analysis
- GRB 110205A: LOAO B/R Observation
- GRB 101225A is likely at z~0
- GRB 110205A: optical flare confirmation
- GRB 110205A: NOT redshift confirmation
- GRB 110205A: Enhanced Swift-XRT position
- GRB 110205A: FAST Redshift
- GRB 110205A: GRAS005 optical observations
- GRB 110205A: PAIRITEL NIR Afterglow Detection
- GRB 110205A: Possible Lick/Kast redshift
- GRB 110205A: Swift/UVOT Confirmation of Flaring Afterglow
- GRB 110205A: Liverpool Telescope Afterglow Confirmation
- GRB 110205A: TAROT Calern observatory detection of an optical flare
- GRB 110205A: ROTSE-III, Optical Counterpart is flaring to ~14 mag
- GRB 110205A: TAROT Calern observatory optical detection
- GRB 110205A: Swift detection of a burst with an optical candidate
- GRB 110128A: Fermi GBM detection
- GRB 110201A: Swift-XRT refined Analysis
- GRB110201A: MITSuME Okayama optical upper limits
- Swift/UVOT observations of GRB110201A
- GRB 110201A: Swift-BAT refined analysis
- GRB 110201A: MASTER optical observations
- GRB 110201A: Swift detection of a burst
- GRB110112B: EVLA Observations
- GRB101224A: EVLA Observations
- GRB110112A: EVLA Observations
- GRB110128A: MITSuME Okayama optical upper limits
- GRB 110125A: Fermi GBM detection
- GRB 101112A: Maidanak and CrAO optical observations
- GRB110128A: TNG NIR observations
- GRB 110128A, Swift-BAT refined analysis
- GRB 110128A: TAROT-Calern refined analysis
- GRB 110128A: Swift/UVOT observations
- GRB 110128A: Swift-XRT refined Analysis
- GRB 110120A: Suzaku WAM observation of the prompt emission
- GRB 110128A: WHT redshifts of nearby field galaxies
- GRB 110128A: VLT/X-shooter redshift
- GRB 110128A: Enhanced Swift-XRT position
- GRB 110128A: Afterglow detection from NOT
- GRB 110128A: TAROT Calern observatory upper limits
- GRB 110128A: Swift detection of a burst
- IBAS Alerts n. 6130 and 6131 are not due to a GRB
- Konus-Wind observation of GRB 110120A
- GRB 110123A: Fermi GBM detection
- GRB 110106B, radio observations
- GRB 110120A: MASTER optical observations
- GRB 110120A: Fermi LAT detection
- GRB 101224A, the review of the sky area in plate archives
- IPN triangulation of GRB 110120A
- GRB 101225A: CQUEAN optical observation
- GRB 110106A: CrAO optical observations
- GRB 110119A: Fermi GBM detection
- GRB 110120A: Fermi GBM detection
- GRB 110119A: Suzaku WAM observation of the prompt emission
- GRB 110112A: optical upper limit
- GRB 110120A: MASTER optical observations
- GRB110119: Swift/UVOT Detection
- GRB 110119A: Swift-XRT refined Analysis
- GRB110119A: MITSuME Okayama optical upper limits
- GRB 110119A: Swift-BAT refined analysis
- GRB 110119A: PAIRITEL NIR Afterglow Detection
- GRB 110119A: Enhanced Swift-XRT position
- GRB 110119A: Swift detection of a burst with an optical detection
- GRB110106A, mm-radio observations
- GRB 101219B: tentative redshift and spectroscopic supernova detection
- GRB 101219B: GROND detection of a SN signature
- Swift-BAT trigger 442771 is a noise fluctuation
- GRB 101219B: correction
- GRB 101219B: Likely the GRB host emission dominates now in the uvw2 filter
- New feature in Fermi GBM GRB Ground Position Notices
- Swift-BAT Trigger 442539 is not a GRB
- Swift Trigger 442539 is probably not a GRB
- Short GRB 110112B : early optical limit by "Pi of the Sky"
- GRB101225A - timing analysis
- GRB 110112B: Fermi GBM observation
- The Christmas burst GRB 101225A - optical spectroscopy with GTC
- GRB 110112B: Swift XRT and UVOT observations of the INTEGRAL burst
- GRB 110112A: MITSuME Akeno and Okayama optical upper limits
- GRB 110107A: Swift-XRT afterglow confirmation
- GRB 101225A: HST observations - no host detected
- GRB 101225A: Redshift retraction and results of additional photometric follow-up at the NOT
- GRB 110112B: A short GRB detected by INTEGRAL
- GRB 110112A: Swift-XRT refined Analysis
- GRB 110112A: Swift/UVOT upper limits