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"- IPN Triangulation of GRB 120602A (long/very bright)
- GRB 120614A: MAXI/GSC detection of a burst
- GRB 120612A: optical observations
- GRB 120612A: Swift/UVOT observations
- GRB 120612A: Swift-XRT refined Analysis
- GRB 120612A: Swift-BAT refined analysis
- GRB 120612A: Enhanced Swift-XRT position
- GRB 120612A: BOOTES-3 optical upper limit
- GRB 120612A: Swift detection of a burst
- GRB 120603A: Suzaku WAM observation of the prompt emission
- GBM triggers 120604.526 & 120604.399 were not GRBs
- Konus-Wind observation of GRB 120603A
- IPN Triangulation of short GRB 120603A
- Fermi GBM trigger 120602.539 is not a GRB
- Konus-Wind observation of GRB 120528B
- GRB 120519A: Suzaku WAM observation of the prompt emission
- GRB 120528C: MAXI/GSC detection
- GRB 120521C redshift estimate
- Fermi Gamma-ray Burst Monitor trigger 120527.573 is not a GRB
- GRB 120528B: MAXI/GSC detection
- GRB 120512A: Suzaku WAM observation of the prompt emission
- GRB 120521C: EVLA Localization of Afterglow
- GRB 120521C: EVLA 22 GHz Detection
- GRB120521B: SSO 2.3m upper limits
- Konus-Wind observation of GRB 120522A
- IPN triangulation of GRB 120522A (long/intense)
- GRB 120521B: Fermi GBM observation
- GRB 120521A: ATCA 34GHz upper limit
- GRB 120521C: Early Tautenburg limits
- GRB 120521C: EVLA 22 GHz Upper Limit
- GRB 120521A: GROND Upper limits
- GRB 120521C: Swift-XRT refined Analysis
- GRB 120521C: Swift-BAT refined analysis
- GRB 120521C: Keck Observations
- GRB 120521C: Swift/UVOT Upper Limits
- GRB 120521B: Swift/UVOT Upper Limits
- GRB 120521C: MASTER optical limit
- GRB 120521B: GROND Upper limits
- GRB 120521A: XRT light curve (Correction to GCN 13326)
- GRB 120521A: Swift-XRT refined Analysis
- GRB 120521C: PAIRITEL NIR Upper Limits
- GRB 120521C: Enhanced Swift-XRT position
- GRB 120521C: BOOTES-1 optical observations
- GRB 120521C: WHT optical observations
- GRB 120521C - NOT optical limits
- GRB120521C: Liverpool Telescope observations
- GRB 120521C: TAROT Calern observatory optical observations
- GRB 120521C: Swift detection of a burst
- GRB 120521B: Swift-BAT refined analysis
- GRB 120521B: Swift-XRT refined Analysis
- Konus-Wind observation of GRB 120519A
- Swift starts a new program to find fainter transients
- IPN Triangulation of GRB 120519A (short/hard)
- GRB 120521A: Swift/UVOT Upper Limits
- GRB 120521B: Enhanced Swift-XRT position
- GRB 120521A: Swift-BAT refined analysis
- GRB 120521B/Fermi Trigger 359284074: early MASTER-ICATE optical limit
- Correction to GCN 13307 (GRB120521B)
- GRB120521B: Faulkes Telescope South observations
- GRB 120521B: TAROT La Silla observatory optical observations
- GRB 120521B: Swift detection of a burst
- GRB 120521A: Enhanced Swift-XRT position
- GRB 120521A: TAROT La Silla observatory optical observations
- GRB 120521A: Swift detection of a short burst
- GRB 120514A : Suzaku WAM observation of the prompt emission
- GRB 120512A: A long GRB detected by INTEGRAL
- Swift Trigger 522245 is a noise fluctuation near IGR J17091-3624
- GRB 120514A: GROND upper limits
- GRB 120514A: Swift/UVOT Upper Limits
- GRB 120514A: UKIRT IR observations
- Konus-Wind observation of GRB 120510A
- GRB 120514A: Swift-XRT refined Analysis
- GRB 120514A: APEX observations of the submm counterpart
- GRB 120514A: Enhanced Swift-XRT position
- GRB 120514A: Swift-BAT refined analysis
- GRB 120514A: TAROT Calern observatory optical observations
- GRB 120514A: Swift detection of a burst
- GRB 120422A: Konkoly optical observations
- Fermi GBM Trigger 358364818 is not a GRB
- Fermi Trigger 358364818: BOOTES-4 observations
- GRB 120510B/Fermi Trigger 358364818: MASTER possible OT candidate
- GRB 120510A: Swift XRT and UVOT observations
- GRB 120510A: MASTER follow up observations
- GRB 120510A: MAXI/GSC detection of a burst
- GRB 120422A: SN identification from GTC
- Fermi/GBM detection of a burst from the magnetar 1E 2259+5
- GRB 120422A: P200 NIR detection
- GRB 120422A: CARMA 3mm observations
- GRB 120422A: VLT/X-shooter spectroscopic evidence for a SN
- GRB 120422A: Gemini-N detection of a supernova
- GRB 120422A: i-band re-brightening and possible SN detection
- GRB 120427A: MASTER follow up observations
- GRB 120422A: optical observations
- Konus-Wind observation of GRB 120427A
- IPN Triangulation of GRB 120427A
- Swift detection of 4U 1630-47
- GRB 120422A, the review of the sky area in plate archives
- Konus-Wind observation of GRB 120426A
- GRB 120422A: Additional Gemini observations and Keck/LRIS spectroscopy
- IPN Triangulation of bright GRB 120426A