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"32542 results found.
- GRB081007: Swift/UVOT Observations
- GRB 081007, SMARTS optical afterglow observations
- GRB 081007, Swift-BAT refined analysis
- GRB 081007: Early RAPTOR measurements of optical counterpart
- GRB 081007: Swift-XRT Team refined analysis
- GRB 081007: Gemini-south redshift
- GRB 081007, Faulkes Telescope North optical observations
- GRB 081007, SMARTS optical/IR afterglow observations
- GRB 081007: REM NIR and optical counterpart
- Fermi GBM detection of additional bursts from AXP 1E1547.0-5408
- INTEGRAL ToO observation of the AXP 1E 1547.0-5408
- AXP 1E 1547.0-5408: Swift/UVOT Upper Limits
- GRB 081003B: Swift-XRT upper limit
- GRB 081003A: OSN optical observations
- GRB 081001: Further observations from OSN
- AXP 1E1547.0-5408: Swift-XRT Team refined analysis
- GRB 081003A: Swift-XRT Team position and analysis
- Swift-BAT refined analysis of AXP 1E1547.0-5408 (Trigger 330353)
- GRB 080928: Fermi GBM detection
- AXP 1E1547.0-5408 (SGR 1550-5418): Fermi GBM detection
- SGR 1550-5418 = AXP 1E1547.0-5408 (Trigger 330353)
- Swift discovery of a new Soft Gamma Repeater SGR 1550-5418
- GRB 081001: Observations from OSN
- GRB 080925: Suzaku WAM observation of the prompt emission
- GRB 081001: Swift UVOT Observations
- GRB 081001: Swift-XRT position
- GRB081001: optical limit from ASH-Centurion
- GRB080928: redshift retraction
- GRB 080928: Watcher observations
- GRB 080928: VLT redshift
- GRB080928: Gemini-South Absorption Redshift
- GRB 080928: Swift-XRT refined analysis
- GRB 080928: Swift/UVOT observations
- GRB 080928, Swift-BAT final refined analysis
- GRB 080928: GROND DETECTION
- GRB 080928, Swift-BAT initial refined analysis
- GRB 080928A: ROTSE-III Confirmation of Optical Counterpart
- GRB080922, optical upper limit
- Swift-BAT trigger 325707 is not a GRB
- Swift trigger 325707: Swift/UVOT Upper Limits
- Swift trigger 325707: Swift-XRT upper limit
- GRB080916A: Suzaku WAM observation of the prompt emission
- GRB 080922: Swift/UVOT Upper Limits
- GRB080922: Swift-XRT upper limit
- GRB 080916C: Fermi GBM Spectral Analysis
- GRB 080919: Swift/UVOT Refined Analysis
- GRB 080919: Swift-XRT refined analysis
- GRB 080919, Swift-BAT 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 080915A: GROND upper limits
- GRB080913: Swift-BAT spectral lag
- GRB 080916A: GROND lightcurve
- SGR 0501+4516: preliminary results of the Suzaku ToO observation
- GRB 080916A: Rapid PROMPT Observations
- GRB 080916A: Fermi GBM detection
- GRB 080916C: Swift UVOT Refined Analysis
- GRB 080916C: Swift XRT refined analysis
- GRB 080916B: Swift-XRT refined analysis
- Konus-Wind observation of GRB 080916A
- Konus-Wind observation of GRB 080916C
- GRB 080916C: GROND Detection of the Optical Afterglow Candidate
- GRB 080913: Konus-Wind and Swift/BAT joint spectral analysis
- GRB080916A: Spectroscopic redshift
- GRB 080916C: Swift/XRT detection of possible afterglow
- GRB 080916B: Swift UVOT Refined Analysis
- IPN Triangulation and Energy Spectrum of GRB080916C
- GRB 080916B, Swift-BAT refined analysis
- GRB080916A: Refined Swift/UVOT Observations
- GRB 080915a, SMARTS optical/IR observations
- GRB 080916C: Fermi LAT observation
- GRB 080916A: Swift XRT refined analysis
- GRB 080916A, Swift-BAT refined analysis
- GRB 080916: REM detection of the NIR afterglow
- GRB 080916: REM candidate afterglow
- GRB 080915B, Swift-BAT refined analysis
- 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 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: GROND observation of a high-z optical/NIR afterglow candidate
- GRB 080906: Watcher observations
- Swift-BAT/-XRT refined analysis on trigger 324362 (LS I +61 303)
- SGR J0501+4516: radio pulsar searches with GBT and WSRT
- Swift trigger 324362 (LS I +61 303 ?): XRT
- GRB080905A: Swift/UVOT Upper Limits
- GRB 080905B: Watcher optical detection
- GRB 080905B: Fermi Gamma-ray Burst Monitor detection
- GRB 080905A: Fermi Gamma-ray Burst Monitor detection