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 070802: REM optical observations
- GRB 070724B: Swift-XRT afterglow confirmation
- GRB 070802: Swift-XRT refined analysis
- GRB070802: Swift/UVOT upper limits
- GRB 070802: Confirmation of the optical afterglow
- GRB 070802, Swift-BAT refined analysis
- GRB 070802: VLT redshift
- GRB 070802: refined Swift XRT position
- GRB 070802: V-band detection of the candidate afterglow
- GRB 070802: LCO I-band candidate
- GRB 070802: GROND J band candidate
- GRB 070802: LCO optical observations
- GRB 070802: Swift detection of a burst
- GRB 070731, Swift-BAT refined analysis
- Konus-A observation of GRB 070729
- Swift/UVOT detection of GRB070714B
- AGILE-ACS position for the SGR 1806-20 July 27 burst
- GRB 070724B: pseudo-z ~ 1.10 from prompt emission spectrum
- GRB 070729: LCO optical imaging
- VLA upper limit on short hard burst GRB 070714B
- Intense burst from SGR 1806-20 detected on July 27
- GRB070729: Swift/UVOT upper limits
- GRB 070729: Swift-XRT refined analysis
- GRB 070729, Swift-BAT refined analysis
- GRB 070729: Magellan NIR Observations
- GRB 070724B: P60 Observations
- GRB 070729: Swift detection of a short hard burst
- GRB 070724B: Swift/UVOT Upper limits
- GRB070721A: Swift/UVOT Detection of a Weak Afterglow
- GRB 070724B: Swift-XRT afterglow likely candidate
- GRB 070721A: optical observations
- GRB 070724A: further VLT observations
- GRB 070724B: Suzaku WAM observation of the prompt emission
- Konus-Wind observation of GRB 070724B
- GRB 070724B: Analysis of AGILE gamma-ray data
- GRB 070724B: Swift-XRT afterglow candidates
- GRB 070724b: First Gamma Ray Burst Localization by SuperAGILE onboard
- Four radio sources in Swift-XRT error box of GRB 070724
- GRB 070724: optical observations
- GRB070724: Host galaxy redshift
- GRB 070724: P60 and Gemini Observations
- GRB 060814 - Keck host detection and redshift
- GRB 070724: IR observations
- GRB 070724: Closer association with DSS source
- Swift/UVOT refined analysis of GRB070724
- GRB 070724: Swift-XRT Team refined analysis
- GRB 070724: Pre-Imaging Shows a Source in the XRT Error Circle
- Short-Hard GRB070714B: PROMPT Observations
- GRB 070724, Swift-BAT refined analysis of a short burst
- GRB 070721B: further observations and analysis
- GRB 070724: Swift detection of a burst
- GRB 070326: Detection of first burst from BAT Slew Survey (BATSS)
- GRB 070714B: Keck observations
- GRB 070721B: optical observations and proposed redshift
- Swift/UVOT observations of GRB070721B optical afterglow.
- GRB 070721B, Further Swift-BAT refined analysis
- Swift/UVOT Observations of GRB070721A
- GRB 070721B : Faulkes Telescope South observations
- GRB 070721B: Swift-XRT refined analysis
- GRB 070721A : Faulkes Telescope South optical limit
- GRB 070721A: Swift/XRT refined analysis
- GRB 070721B, Swift-BAT refined analysis
- GRB 070721A, Swift-BAT refined analysis
- GRB070721B: A bright UVOT candidate
- GRB 070721B: Swift detection of a burst
- GRB 070721: Swift detection of a possible burst
- GRB 070714B: Swift/BAT and Suzaku/WAM joint spectral analysis
- GRB 070714B : Suzaku WAM observation of the prompt emission
- GRB 070714A: Swift-BAT T_zero
- GRB070714B: TNG NIR observations
- Erratum : Suzaku WAM observation of GRB 070704
- GRB 070714A: Swift/UVOT Upper limits
- GRB 070714B: Swift/UVOT Upper Limits
- GRB 070714B: Swift-BAT spectral lag for the SHB
- GRB 070714B: confirmation of optical afterglow
- GRB 070616: No Evidence for I Band Afterglow
- GRB 070714A: Swift XRT refined analysis
- GRB070714B: Swift-XRT refined analysis
- GRB 070707: Swift-XRT follow-up observations
- GRB 070714b ("Bastille"): Optical Pre-Imaging (Clarification)
- GRB 070714 ("Bastille"): Optical Pre-Imaging
- GRB 070714B, Swift-BAT refined analysis of the short hard burst
- GRB 070714A, Swift-BAT refined analysis
- GRB 070714 : Liverpool Telescope optical counterpart ?
- GRB 070714: Swift detection of a bright burst, possibly short
- Swift detection of a possible burst (Trigger 284850)
- SN 2007bg - off-axis GRB?
- GRB 070704: RTT150 optical observations
- GRB 070704: Suzaku/WAM observation of the prompt emission
- Konus-Wind observation of GRB 070707
- Updated Swift/UVOT calibration
- GRB 070707: optical afterglow
- GRB 070707: object inside XRT error circle
- Swift/UVOT Observations of GRB070707
- Swift XRT observation of GRB 070707
- GRB 070707: VLT observations
- INTEGRAL GRB 070707 is a short hard burst
- INTEGRAL GRB 070707 is a short hard burst
- GRB 070707: A long GRB detected by INTEGRAL
- GRB 070707: A long GRB detected by INTEGRAL