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"26357 results found.
- GRB 050826: Optical Candidate
- GRB 050826: Swift XRT preliminary analysis results
- GRB 050826: BAT refined analysis
- GRB050826: Swift/UVOT early upper limits
- GRB050826: Swift-BAT detection of a long burst
- GRB050824: MASTER final analysis of the OT observations
- Swift-BAT trigger 152038 is probably not a GRB
- GRB 050824: XRT refined analysis and possible afterglow detection
- GRB 050824: BAT refined analysis of a soft weak burst
- GRB050824: MASTER:OT decay
- GRB050824: MASTER observation OT
- GRB050805a: MASTER optical candidat
- XRF050509c: Radio upper limits from GMRT
- GRB050822: Swift/UVOT upper limits
- GRB 050820A BAT observations of second, larger episode of emission
- GRB050813: Maidanak I-band observations
- GRB 050822: Swift-BAT refined analysis
- GRB050525, GRB050607, GRB050802 BVRcIc field photometry
- GRB050820B at FRAM
- Swift/UVOT UV Photometry of GRB 050820B
- GRB 050822: Swift detection of a long burst
- GRB050820a BVRcIc field photometry
- GRB050820B XMM-Newton observation
- GRB 050820a: NIR Observations by WIRO
- GRB 050820B: Swift XRT position
- GRB050820B: Refined analysis of the Swift-BAT burst
- GRB050820: refined XRT analysis
- GRB 050820 Swift-BAT refined analysis
- GRB050819: refined XRT analysis
- GRB 050820: Swift detection of a GRB
- GRB 050819 Swift-BAT refined analysis
- GRB050819: Swift-BAT detection of a weak burst
- GRB 050817: Optical observations
- GRB050817: Negative Optical Observations
- GRB 050814: continued fading
- GRB050815: Optical afterglow detection by Swift UVOT
- GRB050815: XRT refined analysis
- GRB050815: Refined analysis of the Swift-BAT burst
- GRB 050815: ROTSE-III Optical Limits
- GRB050815: Swift-BAT detection of a burst
- GRB050814: Fading red source
- GRB050814: P60 Optical Afterglow Candidate
- GRB 050813: Non-fading of afterglow candidate
- GRB 050814: XRT refined analysis
- GRB050814: SWIFT/UVOT observation
- GRB050814: Refined analysis of the Swift-BAT burst
- GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
- GRB 050814: Swift XRT Afterglow Localization
- GRB 050814: Swift detection of a burst
- GRB 050813: Magellan detection of a high redshift galaxy cluster
- GRB050813, SDSS pre-burst observations
- GRB 050813: Swift-BAT refined analysis
- GRB 050813: Photometry of object in XRT error circle
- GRB050813: SWIFT/UVOT observation
- GRB 050813: Swift XRT afterglow localization
- Ongoing activity of SGR 1806-20: an intermediate burst 050811
- Detection of an intermediate burst from SGR 1806-20 on August 8
- GRB050805b: CrAO optical limit
- GRB050803, optical observations
- Retraction of Swift Trigger 149131 (GRB 050805B)
- GRB 050805b: OHP optical limits
- GRB 050805b: TAROT optical limits
- GRB050805b: MASTER optical observations
- Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
- GRB050805a: MASTER optical candidat
- GRB050802: TNG optical observations
- GRB050803: Radio Observation
- GRB 050803: RTT150 optical observations
- GRB050801: Radio Observation
- GRB050730: Radio Detection
- GRB 050803: Keck Observations
- GRB 050803: Swift-BAT refined analysis
- GRB 050802.422: Fading of the afterglow and detection of the host
- GRB 050803: early Swift XRT analysis results
- GRB 050803: TAROT optical limits
- GCN GRB observation 050713A
- GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
- GRB050802 radio non-detection
- GRB 050730: OHP optical observations
- GRB 050802: early Swift XRT analysis results
- GRB 050802: Swift/UVOT observations
- GRB 050802: Swift-BAT refined analysis
- GRB050801: Optical photometry and decay index
- GRB 050802: Swift Gamma-ray Burst
- GRB050801: Swift/UVOT Optical and UV detections
- GRB 050730: Preliminary Analysis of MIKE Spectrum
- GCN 050801: early Swift XRT analysis results
- GRB 050801: Swift-BAT refined analysis
- GRB 050730: XRT refined analysis
- GRB 050730: early TAROT optical observations
- GRB 050730, spectra and optical photometry
- GRB050730: Refined BAT analysis of the Swift-BAT burst
- GRB 050730 XMM-Newton observation
- GRB050730: Swift-BAT detection of a weak burst
- GRB050713b: Maidanak optical observations
- GRB 050724: Secure Host Redshift from Keck
- GRB 050724: WHT optical observations
- GRB050713: analysis of the XMM-Newton observation
- Swift-BAT trigger 147918 is not a real GRB
- GRB050724: VLT observations of the variable source