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.
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
- GRB 050820: Early RAPTOR detections
- GRB 050820 Swift-BAT refined analysis
- GRB 050820: P60 Temporal Decay Index
- GRB 050820: High Resolution Spectroscopy from Keck
- GRB050819: refined XRT analysis
- GRB050819: RTT150 optical observations
- GRB 050820: Swift detection of a GRB
- GRB050820: Optical afterglow from P60
- GRB 050819 Swift-BAT refined analysis
- GRB050819: Swift XRT position
- GRB050819: Swift-BAT detection of a weak burst
- Swift-BAT trigger 150993 is not a GRB
- Swift Trigger 150823 is HETE J1900.1-2455
- GRB 050817: Optical observations
- GRB 050815: Radio Observation
- GRB050814: Radio Observation
- GRB050817: Negative Optical Observations
- GRB050817: Swift-BAT Detection of a burst
- GRB 050814: continued fading
- GRB050815: Optical afterglow detection by Swift UVOT
- GRB050815: XRT refined analysis
- GRB 050813: Radio Observations
- GRB050815: Refined analysis of the Swift-BAT burst
- GRB 050815: ROTSE-III Optical Limits
- GRB050815: Swift XRT afterglow localization
- GRB050815: Swift-BAT detection of a burst
- GRB 050730: Third Epoch WSRT Radio Observations
- GRB050814: Fading red source
- GRB 050813: Gemini Spectra Revisited
- 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
- GRB050813: Gemini Imaging
- 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: RTT150 optical observations
- GRB 050813: I-band observations
- GRB050813, SDSS pre-burst observations
- GRB 050813: KAIT optical limit
- 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
- RBO GRB 050714A and GRB 050716 observations
- GRB 050813: Possible Short Swift-BAT GRB
- GRB050813 (Swift 150139): P60 Observations
- Swift-BAT trigger 150131 is not a GRB
- GRB050807(=H3889): An X-Ray Rich GRB Localized by HETE
- Ongoing activity of SGR 1806-20: an intermediate burst 050811
- GRB050803: CrAO optical observations, no OT candidate
- Detection of an intermediate burst from SGR 1806-20 on August 8
- GRB 050730: WSRT Radio Observations
- GRB 050803: PROMPT BVRcIc Observations
- GRB 050807: ROTSE-III Optical Limits
- GRB 050730, optical observation
- GRB050805b: CrAO optical limit
- GRB050805a : Null detection report
- GRB050730, optical observations
- GRB050803, optical observations
- Swift-BAT trigger 149118 is very likely not a GRB
- 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
- Swift-BAT trigger 149118 is probably not a GRB
- GRB050802: TNG optical observations
- GRB050803: Radio Observation
- GRB 050803: RTT150 optical observations
- GRB050801: Radio Observation
- GRB050730: Radio Detection
- GRB050803: CrAO optical observations, possible OT candidate
- GRB050803: Optical/UV Upper Limits from Swift-UVOT
- GRB 050803: Keck Observations
- GRB 050803: Swift-BAT refined analysis
- GRB 050802.422: Fading of the afterglow and detection of the host
- GRB050803: MASTER further analys
- GRB 050803, optical observations
- GRB 050803: Magellan Observations
- GRB 050803: early Swift XRT analysis results
- GRB 050803: TAROT optical limits
- GRB050803: MASTER optical observations
- GRB050802: Tentative absorption redshift
- GRB050803: Swift-BAT detection of a very long burst
- GCN GRB observation 050713A
- GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
- GRB 050802: Swift/UVOT optical and UV detections
- GRB050802: CrAO optical observations
- GRB050801: Unchanged decay slope
- GRB050802 radio non-detection
- GRB 050730: OHP optical observations
- GRB 050802: early Swift XRT analysis results
- GRB 050802: Swift/UVOT observations
- GRB 050802 : Lulin Optical follow-up observation
- GRB 050802: Swift-BAT refined analysis