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"15987 results found.
- INTEGRAL Weak trigger #6331: GRT Optical Observation
- GRB 110726A: optical upper limit in CrAO
- GRB 110726A: EVLA observations
- GRB 110726A: IAC80 R-band observations
- GRB 110726A: ROTSE-III refined analysis, fast decay in early phase
- GRB110726A: MITSuME Ishigakijima Optical Observation
- GRB 110726A: Liverpool Telescope observations
- GRB 110726: ROTSE-III Detection of Optical Counterpart
- GRB 110721A: Preliminary Swift/UVOT Upper Limits
- GRB 110721A: Gemini-South spectroscopy of the potential optical counterpart
- GRB 110721A: potential counterpart candidate
- GRB 110709B / EVLA detection of radio counterpart
- GRB 110719A: GRT Optical Observation
- GRB 110719A: optical limit by "Pi of the Sky"
- Swift/UVOT observations of GRB110719A
- GRB 110719A: optical upper limit
- GRB 110715A optical observations
- Swift J1822.3-1606: Transient Magnetar or Be X-ray Binary?
- GRB110715A: GROND Detection of the Optical/NIR Afterglow
- GRB 110715A: APEX detection of the submm counterpart
- GRB110715A: VLT redshift
- GRB 110715A: Swift detection of a bright burst with an optical counterpart
- GRB 110709B: Additional Gemini observations and deep limits on an optical afterglow
- GRB 110709A: Swift/UVOT Upper Limits
- GRB 110709B: Swift/UVOT Detection of Possible Optical Flaring
- GRB110709A: MITSuME Ishigakijima Optical upper limits
- GRB 110709B: Gemini-South optical observations
- GRB 110709B: possible quiescent source in DSS
- GRB 110709A: MASTER-NET optical observations
- GRB 110708A: Liverpool Telescope observations
- SGR 1E 1841-045: early optical limit by "Pi of the Sky"
- GRB 110625A: Swift/UVOT Upper Limits
- GRB 110625A: GROND detection of a source inside the XRT error circle
- GRB 110625A: ROTSE-III Optical Limits
- Swift J185003.2-005627: Swift-XRT/UVOT refined analysis
- Swift J185003.2-005627: TAROT La Silla observatory optical observations
- Swift J185003.2-005627: TAROT Calern observatory optical observations
- GRB 110618A: SMARTS optical observations
- GRB 110610A: 1.23m CAHA optical observations
- GRB 110610A: Swift/UVOT Upper Limits
- Swift detection of the X-ray afterglow of GRB 110604A
- GRB 110610A: MASTER-NET optical observations
- GRB 110530A: optical observations in Mondy observatory
- GRB 110530A: optical observations at Mt. Terskol, second epoch
- GRB 110530A: Xinglong TNT observation
- GRB 110530A: NOT optical observations
- GRB110530A: MITSuME Okayama Optical Observation
- GRB 110530A: optical observations at Mt. Terskol
- GRB 110530A: MASTER OT observations
- GRB 110530A: MITSuME Akeno Optical Observation
- GRB 110530A: Swift detection of a burst with an optical afterglow
- Swift J1644+57/GRB 110328A, Additional HST Observations
- GRB 110521A: MASTER prompt optical limit
- GRB 110521A: Swift/UVOT Upper Limits
- GRB 110520A: NOT optical follow-ups
- GRB 110521A - NOT optical observation
- GRB 110521A: MASTER synchronous and early optical observations limit
- Swift/UVOT observations of GRB110520A
- GRB 110520A - NOT optical observation
- GRB 110520A: Skynet/DAO optical observations
- GRB 110520A: Liverpool Telescope Observations
- GRB 110520A: TAROT Calern observatory optical observations
- GRB 110520A: MASTER-NET optical observations
- GRB 110503A optical observation
- GRB 110503A: TAROT Calern observatory optical observations
- GRB 110503A optical observations
- GRB 110503A: optical observation in CrAO
- GRB 110503A: Millimeter observation from SMA
- GRB 110503A: Swift/UVOT Observations
- GRB 110503A: PAIRITEL NIR Detection
- GRB 110503A: redshift confirmation from TNG
- GRB 110503A: NOT afterglow photometry
- GRB 110503A: Swift detection of a burst with a bright optical counterpart
- GRB 110422A: optical observations in CrAO
- GRB 110422A: Update of Herschel FIR observation schedule
- GRB 110422A: optical observations in CrAO, second epoch
- GRB110422A: NOT optical follow-ups
- GRB 110422A: optical observations in CrAO
- GRB110422A: MITSuME Ishigakijima Optical Observation
- GRB 110422A: Further NOT observation
- GRB 110422A: Swift/UVOT Detection of optical afterglow
- GRB 110422A: THO optical observations
- GRB 110422A: TNG optical observations
- GRB 110422A: SAO RAS optical observations
- GRB 110422A: NOT optical observation
- GRB 110422A: MASTER earlier OT polarization observations
- GRB 110422A: Mondy optical observations
- GRB 110328A/Swift J164449.3+573451: Maidanak Optical Observation
- GRB 110420B: Swift/UVOT Upper Limits
- GRB110420A: GROND detection of the Optical/NIR Afterglow Candidate
- GRB 110420A Swift/UVOT Observations
- GRB 110420A: Swift detection of a burst with optical counterpart
- GRB110414A: MITSuME Ishigakijima Optical upper limits
- GRB110414A: MITSuME Okayama Optical upper limits
- GRB 110414A: Swift/UVOT Upper limits
- GRB 110411A: PAIRITEL NIR Upper Limits
- GRB 110411A: optical limits from OSN
- GRB 110411A: Swift/UVOT Upper Limits
- GRB 110411A: MASTER prompt and follow-up optical limits
- GRB 110411A : Xinglong TNT OT candidate