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"5401 results found.
- Trigger 631747: Swift detection of 4U 0614+09
- GRB 150212A: Swift-XRT afterglow detection
- Trigger 630047: Swift detection of 1RXS J180408.9-342058
- GRB 150203A: ISON-NM early optical limit
- GRB 150203A: MITSuME Okayama upper limits
- GRB 150203A: Fermi GBM observation
- GRB 150128A: MASTER OT detction during inspection
- GRB 150123A: MASTER inspection
- GRB 150126A: MAXI/GSC afterglow candidate detection
- GRB 150120B: Swift-BAT refined analysis
- GRB 150120A: P60 optical observations
- Swift detection of 4U 1700+24 (= V* V934 Her)
- GRB 150103A: MASTER optical observations
- Swift J123205.1-105602: XRT and UVOT observations of soft short burst source
- GRB 141230A: Fermi GBM detection
- GRB 141230A: iPTF Optical Observations and Candidate Afterglow iPTF14jko
- GRB 141225A: MASTER-SAAO OT light curve
- GRB 141225A: very early T60 observations
- GRB 141225A: MASTER-SAAO first OT detection
- Swift detection of 4U 1700+24 (= V934 Her)
- GRB 141202A: Swift XRT observations
- IPN Triangulation of GRB 141202A (short/hard)
- IPN Triangulation of GRB 141121A (initial episode)
- GRB 141121A: SPI-ACS/INTEGRAL observations
- IPN Triangulation of GRB 141125A (short/hard)
- GRB141124A: MASTER Detection of New Flare of QSO NVSS J075043+790917 During the Fermi Error Box inspection
- GRB 141121A: MAXI/GSC detection
- GRB141121A: BOOTES-2/TELMA upper limit
- GRB 141121A: Swift detection of a burst
- IPN Triangulation of GRB 141118A
- Swift Trigger 618134 is not an astrophysical event
- GRB 141104A: Swift-XRT observations
- Konus-Wind observation of GRB 141104A
- IPN Triangulation of GRB 141104A (long/very bright)
- GRB 141031B: MITSuME Ishigakijima upper limits
- GRB 141031B: MASTER early optical observations
- GRB 141029B: Fermi GBM detection
- GRB 141026A: Skynet PROMPT-CTIO/Yerkes-41 Observations
- GRB 141026A: SAO RAS Zeiss-1000 observations
- GRB141026A: Deep P200 optical imaging
- GRB 140930B: GROND observations
- Swift detection of outburst from 4U 1700+24
- GRB 140909A: Confirmation of the Swift-XRT afterglow
- GRB 140907A: Mondy optical observations
- GRB 140909A: Swift-XRT observations
- GRB 140907A: MASTER optical observations
- GRB 140907A : Virtual Telescope optical observations
- GRB140907A: Swift UVOT detection
- GRB 140907A : Optical observations from Nanshan
- GRB 140901B: Swift XRT observation
- GRB 140903A: ISON-Kislovodsk observations
- GRB 140903A: MAXI/GSC upper limit
- GRB140903A: Discovery Channel Telescope Optical Detection
- GRB 140829A: iPTF optical observations
- GRB 140824B: Swift observations
- Swift detection of SAX J1712.6-3739
- GRB 140817A: Swift detection of a burst
- GRB 140814A: Swift-XRT and UVOT observations
- GRB 140814A: Swift-XRT and UVOT observations
- GRB 140814A: MAXI/GSC detection
- GRB140809A: Fermi GBM observation
- Swift trigger 609139 is probably 4U 1850-03
- GRB 140801A (FERMI trigger 428612396): MASTER brigth OT discovery
- GRB 140730A: Prompt enhanced Swift-XRT position
- GRB 140729A: Swift-XRT and UVOT observations
- GRB 140723A: LCO-Sutherland optical candidate
- Konus-Wind observation of GRB 140721A
- IPN Triangulation of GRB 140721A
- GRB 140721A: Fermi GBM detection
- GRB 140719A: Swift detection of a burst
- Swift Trigger 604111 is not a GRB
- GRB 140706A: Swift/UVOT Detection
- GRB 140706A: Swift-BAT refined analysis
- GRB 140703A: AAO optical observations
- Pre-discovery observations of SGR 1935+2154 in Swift archival data
- GRB 140706A: Enhanced Swift-XRT position
- GRB 140706A: Swift detection of a burst with an optical counterpart
- GRB 140703A: CARMA 3mm detection
- GRB 140703A: P60 observations of a red, slowly-fading afterglow
- GRB 140703A: Monte Agliale Observatory optical observations
- GRB 140703A: MASTER optical observations
- GRB 140629A: SAO RAS monitoring
- GRB 140621A: Swift-XRT observations
- GRB 140619B: Swift-XRT observations
- GRB 140610A: TShAO optical upper limit
- Konus-Wind observation of GRB 140611A
- IPN Triangulation of GRB 140611A (short/hard)
- Konus-Wind observation of GRB 140606B
- IPN Triangulation of GRB 140606B
- GRB 140606B: Fermi GBM detection
- Fermi423717114: iPTF optical transient candidates
- GRB 140529A: Swift-XRT afterglow detection.
- Konus-Wind observation of GRB 140523A
- IPN Triangulation of GRB 140523A
- GRB 140523A: Fermi-LAT detection
- GRB 140523A: Fermi GBM detection
- GRB 140521A: AROMA-N Optical Observation
- GRB 140515B: MAXI/GSC detection
- GRB 140423A: HCT optical observations
- GRB 140508A: Mondy upper limit