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"- 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
- GRB 070429B: NIR Observations
- GRB070704: FAVOR optical observations
- GRB 070704 : Liverpool Telescope Observations
- GRB 070611: VLT observations
- VLA detection of GRB 070612A in C Band
- Konus-Wind observation of GRB 070626
- GRB 070704: Swift-XRT refined analysis
- Swift/UVOT Observations of GRB070704
- GRB 070704, Swift-BAT refined analysis
- GRB 070704: Correction to GCN Circ 6594
- GRB 070704: Swift detection of a burst
- GRB 070626: Suzaku/WAM observation of the prompt emission
- GRB 070626: IPN localization and Konus spectrum of a bright long burst
- GRB 070628 Swift-UVOT Refined Analysis
- GRB 070628: NIR detection of afterglow
- GRB 070628, Swift-BAT refined analysis
- GRB 070628: TAROT La Silla observatory optical observations
- GRB 070628: Swift XRT refined analysis
- GRB 070628: Watcher Observations
- Swift UVOT Observations of GRB 070628
- GRB 070628: Swift detection of a possible burst
- GRB 070612A: Allen Telescope Array Observations
- IBAS Alert n. 4638: Not a GRB
- OT20050728 was not an optical GRB afterglow
- INTEGRAL burst GRB070615: X-ray continued observations
- GRB 070616 : WIDGET simultaneous optical observations
- GRB 070616: Suzaku/WAM observation of the prompt emission
- IBAS Alert n.4637: not a GRB
- GRB 070612A: Second Epoch WSRT Radio Observations
- GRB070621: RTT150 optical observations
- GRB 070621: VLT optical observations
- GRB 070621: Swift/UVOT Upper Limits
- Keck Laser Guide Star Adaptive Optics Imaging of GRB 070621
- GRB 070621: Swift-BAT refined analysis
- WHT observations of GRB070621
- GRB070621: Swift XRT refined analysis
- GRB 070621: Gemini South optical imaging
- GRB 070621: UVOT-enhanced XRT position
- Observations of GRB070612A at Calar Alto
- GRB 070621: NOT observations
- GRB070621: OPTIMA-Burst optical upper limit
- GRB 070621: TAROT Calern observatory optical observations
- GRB 070621: Watcher Observations
- GRB 070621: ROTSE-III Prompt Optical Limits
- GRB 070621: Swift detection of a burst
- GMRT upper limit of GRB 070610/SWIFT J195509.6+261406 in 610 MHz
- GRB 070612A: TNG optical observations
- Swift/UVOT detection of GRB070616 optical afterglow.
- GRB070612A: Gemini Spectroscopic Redshift
- GRB 070612A: NOT observations
- GRB070616: Optical Observation by MITSuME Akeno
- GRB 070612B: Optical Observation by MITSuME Akeno
- GRB070616: Optical Observation by MITSuME Okayama
- GRB 070616, Swift-BAT further refined analysis
- GRB 070616: Swift XRT refined circular
- GRB 070612A: Possible WSRT Radio Detection