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.
- GRB 121123A: Swift detection of a burst with optical counterpart
- GRB 121117A: optical upper limit
- GRB 121117A: BOOTES-3 early optical upper limit
- Trigger 538084: Swift detection of XTE J1739-302
- GRB 121108A: Swift detection of a burst
- GRB 121102A: Swift detection of a burst
- GRB 121031A: Swift detection of a burst
- GRB 121028A: MITSuME Okayama Optical upper limits
- GRB 121027A: Swift detection of a burst
- GRB 121025A: MAXI/GSC detection
- GRB 121024A: Swift detection of a burst with an optical counterpart
- GRB 120927A: GROND upper limits
- GRB 120923A: Correction to GCN 13823
- GRB 120923A: JHK Observation
- GRB 120923A: MITSuME Okayama Optical upper limits
- GRB 120919B: MASTER prompt optical observations
- IPN Triangulation of long GRB 120919A
- Swift Transient Swift J174510.8-262411: Swift-BAT refined analysis
- Swift Trigger 533836 is a new Galactic transient
- GRB 120913B: TAROT La Silla observatory optical photometry
- GRB 120907A: optical observations of ISON-Kislovodsk
- GRB120911A: MITSuME Okayama Optical upper limits
- GRB 120911A: ROTSE-III Optical Limits
- GRB 120908A and GRB 120909A : Fermi/LAT upper limit
- GRB 120908A: Swift Observations
- GRB 120909A: Fermi GBM observation
- Konus-Wind observation of GRB 120909A
- GRB 120908A: MAXI/GSC detection
- GRB 120909A: GROND detection of the afterglow
- GRB 120909A: Swift detection of a burst
- GRB 120907A: Swift/UVOT Detection
- GRB 120907A: NOT optical observations
- GRB 120907A MASTER optical observations
- GRB 120907A: Swift detection of a burst with optical counterpart
- IPN Triangulation of short GRB 120830A
- IPN Triangulation of GRB 120816B (short/exceptionally intense)
- GRB 120811C: Swift detection of a burst with an optical counterpart
- Trigger 530588: Swift detection of XMM J174457-2850.3
- Swift Trigger 530581: GRB 120811A or a galactic transient
- GRB 120807A: RAPTOR Limits During Gamma-Ray Emitting Interval
- GRB 120807A: Swift detection of a burst
- GRB 120805A: Swift detection of a burst
- GRB 120803B: MITSuME Akeno Optical upper limits
- GRB 120803B: FTN possible afterglow candidate
- GRB 120802A: GRT Optical Observation
- GRB 120728A: GROND Afterglow discovery
- GRB 120729A: Swift detection of a burst with an optical afterglow
- Trigger 529076: Swift possible detection of SwJ1910.2-0546
- GRB 120728A: GROND observations
- GRB 120716A: optical observation in Maidanak observatory
- GRB 120716A: optical observation in CrAO
- GRB 120716A: Swift/XRT position consistent with that of the optical counterpart
- GRB 120716A: Optical decay from NOT
- GRB 120716A: Candidate Optical Afterglow from PTF
- GRB 120714B: Swift detection of a burst
- IPN Triangulation of GRB 120709A
- GRB 120709A: Fermi GBM detection
- GRB 120701A: GROND detection of the afterglow
- Swift Trigger 524949: Noise fluctuation near a galaxy
- GRB 120614A: MAXI/GSC detection of a burst
- GRB 120521B: Fermi GBM observation
- GRB 120521C - NOT optical limits
- IPN Triangulation of GRB 120519A (short/hard)
- GRB 120521B/Fermi Trigger 359284074: early MASTER-ICATE optical limit
- GRB 120521B: Swift detection of a burst
- GRB 120514A: Swift detection of a burst
- GRB 120427A: MASTER follow up observations
- GRB 120422A: optical observations
- Swift detection of 4U 1630-47
- Konus-Wind observation of GRB 120426A
- IPN Triangulation of bright GRB 120426A
- GRB 120422A: EVLA Detection
- GRB 120422A: A Swift/UVOT Detection
- GRB 120422A: Gemini observations
- GRB 120422A: Swift detection of a burst
- GRB 120401A: Swift detection of a burst
- Trigger 518853: Swift detection of a probable Galactic transient
- IPN Triangulation of GRB 120328B (long/intense)
- GRB 120328A: Swift detection of a burst
- GRB 120326A: PAIRITEL NIR Observations
- GRB 120326A: LOAO R-band Observations
- GRB 120327A: Swift detection of a burst with an optical counterpart
- GRB 120326A: CQUEAN grizY Observation
- GRB 120326A: Swift detection of a burst
- GRB 120324A: GROND observations
- Fermi GBM triggers 120309.265 and 120309.402 are not GRBs
- GRB 120311A: C88 optical limits
- GROND observations of GRB 120311A
- GRB 120302A: RTT150 optical observations
- GRB 120308A: Swift detection of a burst
- GRB 120305A: Swift detection of a short burst
- GRB 120302A: GROND detection of an afterglow candidate
- GRB 120227A: RAPTOR Limit During the Gamma-Ray Emitting Interval
- Swift Trigger 516027 is CC Eri
- GRB 120219A: Swift detection of a burst
- Fermi GBM detection of an SGR-like burst
- GRB 120212A: Fermi GBM observation
- GRB 120212A: Swift-XRT observations
- GRB 120212A: Faulkes Telescope South afterglow candidate
- GRB 120212A: Swift detection of a burst