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"5544 results found.
- Swift Triggers 635788-635794 are probably not real.
- GRB 150318A: Skynet PROMPT-CTIO Observations
- GRB 150220A, the review of the sky area in plate archives
- GRB 150314A: P60 observations
- GRB 150313A: MAXI/GSC detection
- GRB 150222A: CrAO optical observation
- GRB 150309A: CrAO optic upper limit
- GRB 150309A: ISON-Kislovodsk optic upper limit
- GRB150309A: Optical observations at Crni Vrh
- GRB 150309A: MASTER prompt optical observation
- GRB 150309A: Swift detection of a burst
- GRB 150305A: a long GRB detected by INTEGRAL
- GRB 150301B: GROND afterglow observations
- GRB 150301A: Fermi GBM observation
- Swift-BAT refined analysis of magnetar 4U 0142+61 (Trigger 632888)
- Fermi GBM Observations of Magnetar 4U 0142+61
- Trigger 632888: Swift detection of the magnetar 4U 0142+61
- GRB 150220A: Swift-XRT observations
- GRB 150222A: GROND optical afterglow candidate
- GRB 150222A: Enhanced Swift-XRT position
- GRB 150222A: Swift-BAT refined analysis
- GRB 150222A: Swift detection of a burst
- Trigger 631747: Swift detection of 4U 0614+09
- GRB 150213B: Swift-BAT refined analysis
- GRB 150213B: Swift detection of a burst with an optical afterglow
- GRB 150210A: MASTER SN detection during LAT error box inspection
- GRB 150206B: Fermi GBM detection
- Trigger 630047: Swift detection of 1RXS J180408.9-342058
- GRB 150206B: iPTF Optical Observations
- GRB 150206A: Swift detection of a burst with an optical afterglow
- GRB 150203A: REM optical and NIR observations
- GRB 150203A: Fermi GBM observation
- GRB 150203A: Swift detection of a burst
- Konus-Wind observation of GRB 150201A
- GRB 150201A: Fermi GBM observation
- GRB 150201A: Swift detection of a burst
- GRB 150128A: MASTER OT detction during inspection
- IPN Triangulation of GRB 150127A
- GRB 150127A: Fermi-LAT detection
- GRB150127A: Fermi GBM Detection
- GRB 150123A: MAXI/GSC detection
- Konus-Wind observation of GRB 150118B
- IPN Triangulation of GRB 150118B (long/intense)
- GRB 150118B: Fermi GBM Detection
- GRB 150118B: Fermi-LAT detection
- The Swift Detection of a Large Flare from the RS CVn Binary SZ Psc
- Swift detection of the variable star SZ Psc
- GRB 150110B: Swift detection of a burst
- Swift detection of 4U 1700+24 (= V* V934 Her)
- GRB 141225A: MASTER-SAAO first OT detection
- GRB 141225A: UVOT detection
- GRB 141225A: Optical aftergow confirmation
- GRB 141225A: LT optical candidate
- GRB 141225A: 1.23m CAHA optical observations
- GRB 141222A: First MASTER-SAAO optical observation
- GRB 141222A: Fermi-LAT detection
- GRB141221A: GROND Afterglow Detection
- GRB 141212A: Swift-BAT refined analysis
- Swift detection of 4U 1700+24 (= V934 Her)
- GRB 141212A: extended object within the XRT error circle
- GRB 141212A: Swift detection of a short burst
- GRB 141202A: Swift/UVOT Detection of a Variable Source Near the IPN Error Box
- GRB 141121A: Mondy optical observations
- IPN Triangulation of GRB 141202A (short/hard)
- GRB 141124A: iPTF upper limits
- GRB 141121A: Swift detection of a burst
- Swift Trigger 618673: probable noise event
- Trigger 618634: Swift detection of Vela X-1
- GRB 141109B: optical upper limits
- Swift Trigger 618402: probable noise event
- GRB 141109B: MITSuME Akeno upper limits
- GRB141109A : Xinglong TNT optical observation
- GRB 141109A: MITSuME Ishigakijima upper limits
- GRB 141109A: CQUEAN Detection at 0.85 - 1.05 micron
- GRB 141109A: GROND afterglow observation
- X-shooter redshift of GRB 141109A
- GRB 141109A: REM NIR candidate afterglow
- GRB 141031A, Swift-BAT refined analysis
- GRB 141028A: SAO RAS Zeiss-1000 photometry
- GRB 140509A: GROND afterglow detection
- GRB 141029A: MAXI/GSC detection
- GRB 141026A: SAO RAS Zeiss-1000 observations
- GRB 141020A: Khureltogot optical upper limit
- GRB 141022A: Swift-BAT refined analysis
- GRB141015A iTelescope observation
- GRB 141020B: MAXI/GSC detection
- GRB 141017A: Swift detection of a burst
- GRB 141015A: LCO-McDonald observations
- GRB 141015A: Super-LOTIS early observations
- GRB 141015A: ISON-NM early optical observations
- GRB 141015A: Swift/XRT localization
- GRB 141015A: Swift detection of a burst
- IPN Triangulation of GRB 141011A (short/hard)
- GRB 141004A: GROND observations
- Swift observations of HD 305560
- Swift possible detection of the Be star HD 305560
- GRB 140930A/MAXI J2259+524: MASTER optical observations
- GRB 140930B: Keck NIR imaging
- GRB 140928A: MAXI-GSC detection
- GRB 140930B: MASTER early optical observations