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 080916C: Fermi GBM Detection
- GRB 080916A: Swift XRT refined analysis
- GRB 080916A, Swift-BAT refined analysis
- GRB 080916B: Swift-XRT afterglow detection
- GRB 080916A: Enhanced Swift-XRT position
- GRB 080916B: Swift detection of a burst
- GRB 080916: REM detection of the NIR afterglow
- GRB 080916: REM candidate afterglow
- GRB 080916: Swift detection of a burst with optical afterglow
- GRB 080915B, Swift-BAT refined analysis
- GRB 080912 : Fermi GBM detection
- GRB 080915B: Swift detection of a burst
- GRB 080915: REM NIR early observations
- GRB 080915: Swift/UVOT Upper Limits
- GRB 080915: Swift-XRT afterglow detection and analysis
- GRB 080915, Swift-BAT refined analysis
- SGR 0501+4516 : P200 i-band observations
- GRB 080915: ROTSE-III Optical Limits
- GRB 080915: Swift detection of a burst
- GRB 080913: Swift-XRT refined analysis
- GRB 080913: VLT/FORS spectrum
- GRB080913: Swift/UVOT Upper Limits
- GRB 080913: GROND photo-z
- GRB 080913, Swift-BAT refined analysis
- 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-BAT/-XRT refined analysis on trigger 324362 (LS I +61 303)
- GRB 080906B: Fermi GBM detection
- GRB 080905C: Fermi GBM detection
- SGR J0501+4516: radio pulsar searches with GBT and WSRT
- Swift trigger 324362 (LS I +61 303 ?): XRT
- GRB 080905B: Photometric Redshift for the 2MASS Galaxy
- Swift trigger 324362 (LS I +61 303 ?)
- GRB080905A: Swift/UVOT Upper Limits
- GRB 080905B: Watcher optical detection
- GRB 080904: Fermi Gamma-ray Burst Monitor detection
- GRB 080905B: Fermi Gamma-ray Burst Monitor detection
- GRB 080905A: Fermi Gamma-ray Burst Monitor detection
- GRB 080905A: Enhanced Swift-XRT position
- GRB 080905A: MITSuME Akeno optical upper limits
- Swift Trigger 324122 is again known source Swift J1842.5-1124
- Swift Trigger 324116 is known source again
- Swift Trigger 324112 is known source Swift J1842.5-1124
- GRB 080906: Refined Swift/UVOT Observations
- GRB 080906: Swift-XRT Refined Analysis
- GRB 080906, Swift-BAT refined analysis
- GRB 080905A: optical afterglow
- GRB 080906: GROND observations of the optical/NIR afterglow
- GRB 080905B: Swift-XRT Refined Analysis
- GRB 080905B: Refined UVOT Analysis
- GRB 080905B: VLT redshift
- GRB 080905A: NOT and VLT observations
- GRB 080905B: Enhanced Swift-XRT position
- GRB 080905B, Swift-BAT refined analysis
- GRB 080905A, Swift-BAT refined analysis
- GRB 080906: Swift detection of a burst with optical afterglow
- GRB 080905A: Swift-XRT Refined Analysis
- GRB 080825C: Fermi GBM Spectral Analysis
- GRB080825C: Fermi-LAT observations
- GRB 080905B: Swift detection of a burst with possible optical counterpart
- GRB 080905: R & I-band optical observations
- 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, Swift-BAT refined analysis
- GRB 080903: optical observations
- GRB 080903: Liverpool Telescope observations
- GRB 080903: Astrotel-Caucasus optical observations
- GRB 080903: Optical afterglow candidate
- GRB 080903: TAROT Calern observatory optical observations
- GRB 080903: ROTSE-III Optical Limits
- GRB 080903: Swift detection of a burst
- Recent VLA non-detection of SGR 0501+4516
- GRB 080830: Fermi Gamma-ray Burst Monitor detection
- SGR 0501+4516: Spin Down Rate and Inferred Dipole Magnetic Field
- SGR 0501+4516: preliminary results of the first XMM-Newton observation
- nIR observations of SGR 0501+4516
- INTEGRAL ToO observation of SGR0501+4516
- SGR 0501+4516: Confirmation of the NIR counterpart
- GRB080828: Swift/UVOT Upper Limits
- SGR 0501+4516: Detection of possible optical counterpart
- SGR 0501+4516: WHT observations of the possible near-infrared counterpart
- GRB080825B: Swift/UVOT Upper Limits
- GRB 080828: Swift-XRT detection of a possible X-ray afterglow
- Swift-BAT trigger 322590 is not a GRB
- VLA non-detection of SGR 0501+4516
- Radio Detection of SGR 0501+4516: Retraction
- Swift trigger 322590: BAT detection of a possible burst
- SGR 0501+4516: XMM-Newton monitoring schedule
- GRB 080828: SuperAGILE GRB Localization
- SGR 0501+4516: Decline in Activity
- SGR 0501+4516: Proximity to supernova remnant HB9
- Enhanced Swift-XRT position of SGR 0501+4516
- SGR 0501+4516: GMRT Radio Observation at 618 MHz
- SGR 0501+4516: Swift XRT measure of the spin period