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"18338 results found.
- Swift trigger 325707: Swift-XRT upper limit
- Swift detection of a possible GRB (trigger 325707)
- GRB 080922: Swift/UVOT Upper Limits
- Trigger 324561: IGR J08408-4503 detected by Swift
- GRB 080919: Swift-XRT refined analysis
- GRB 080916C: IRSF/SIRUS NIR Observation
- GRB 080916C: GROND Confirmation of the Optical Afterglow
- GRB 080916C: GROND Confirmation of the Optical Afterglow
- GRB 080919: REM NIR observations
- GRB 080919: Swift detection of a short burst
- GRB 080915A: GROND upper limits
- GRB 080916A: GROND lightcurve
- GRB 080916A: Fermi GBM detection
- GRB 080916C: Swift UVOT Refined Analysis
- GRB 080916C: Swift XRT refined analysis
- GRB 080916C: GROND Detection of the Optical Afterglow Candidate
- GRB080916A: Spectroscopic redshift
- GRB 080916C: Swift/XRT detection of possible afterglow
- GRB 080916B: Swift UVOT Refined Analysis
- GRB080916A: Refined Swift/UVOT Observations
- GRB 080915a, SMARTS optical/IR observations
- GRB 080916B: Enhanced Swift-XRT position
- GRB 080916C: Fermi LAT observation
- GRB 080916B: Swift-XRT afterglow detection
- GRB 080916A: Enhanced Swift-XRT position
- GRB 080916: REM detection of the NIR afterglow
- GRB 080916: REM candidate afterglow
- GRB 080916: Swift detection of a burst with optical afterglow
- GRB 080915: REM NIR early observations
- GRB 080915: Swift/UVOT Upper Limits
- GRB 080913: Swift-XRT refined analysis
- GRB080913: Swift/UVOT Upper Limits
- GRB 080913: VLT/FORS2 observations
- GRB 080913: REM NIR early observations
- GRB 080913: Enhanced Swift-XRT position
- GRB 080913: GROND observation of a high-z optical/NIR afterglow candidate
- GRB 080913: Swift detection of a burst
- GRB 080906: Watcher observations
- Swift trigger 324362 (LS I +61 303 ?)
- GRB080905A: Swift/UVOT Upper Limits
- GRB 080905B: Watcher optical detection
- GRB 080905A: MITSuME Akeno optical upper limits
- GRB 080906: Refined Swift/UVOT Observations
- GRB 080906: Swift-XRT Refined Analysis
- GRB 080905A: optical afterglow
- GRB 080906: GROND observations of the optical/NIR afterglow
- GRB 080905B: Refined UVOT Analysis
- GRB 080905B: VLT redshift
- GRB 080905A: NOT and VLT observations
- GRB 080905B: Enhanced Swift-XRT position
- GRB 080906: Swift detection of a burst with optical afterglow
- GRB 080905A: Swift-XRT Refined Analysis
- GRB080825C: Fermi-LAT observations
- GRB 080905B: Swift detection of a burst with possible optical counterpart
- GRB 080905: Swift detection of a probably-short burst
- GRB 080903: Swift/UVOT Observations
- GRB 080903: Swift-XRT Refined Analysis
- GRB 080903: Enhanced Swift-XRT position
- GRB 080903: optical observations
- GRB 080903: Liverpool Telescope observations
- GRB 080903: Optical afterglow candidate
- GRB 080903: TAROT Calern observatory optical observations
- GRB 080903: Swift detection of a burst
- SGR 0501+4516: Spin Down Rate and Inferred Dipole Magnetic Field
- SGR 0501+4516: Confirmation of the NIR counterpart
- GRB080828: Swift/UVOT Upper Limits
- SGR 0501+4516: Detection of possible optical counterpart
- GRB080825B: Swift/UVOT Upper Limits
- GRB 080828: Swift-XRT detection of a possible X-ray afterglow
- Swift trigger 322590: BAT detection of a possible burst
- Enhanced Swift-XRT position of SGR 0501+4516
- SGR 0501+4516: GMRT Radio Observation at 618 MHz
- Konus-Wind observation of GRB 080825B
- GRB 080825B: Swift-XRT team analysis
- SGR 0501+4516: Fermi GBM (formerly GLAST Burst Monitor) observations of three exceptionally intense outbursts
- Suzaku ToO Observation of SGR 0501+4516
- SGR 0501+4516: Astrotel-Caucasus optical observations
- SGR 0501+4516: UKIRT detection of possible infra-red counterpart
- SGR 0501+4516: optical observations
- Discovery of the Spin Period of the New Soft Gamma Repeater SGR 0501+4516
- GRB 080822: Swift detection of a short burst
- GRB080810 - optical observations
- Radio detection of GRB 080810 with the VLA
- GRB 080810: Swift/UVOT Refined Analysis
- GRB 080810: Liverpool Telescope observations
- GRB 080810: Kanazawa optical observation
- GRB 080810: OSN follow-up
- GRB 080810: Enhanced Swift-XRT position
- GRB 080810: KANATA optical-NIR observation, update
- GRB 080810 : optical observation with KANATA
- GRB 080810: Swift detection of a burst with a bright optical afterglow
- GRB 080723B: GROND upper limits
- GRB 080805: Faulkes Telescope South optical observations
- GRB 080804: GROND observations
- GRB 080727B: Late VLT imaging
- GRB 080805: Swift-XRT Refined Analysis
- GRB 080805: Swift/UVOT Upper Limits
- GRB 080804: Enhanced Swift-XRT position
- GRB 080804: Faulkes Telescope South observations
- GRB080805 optical limit by "Pi of the Sky"