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"5060 results found.
- GRB 151228A: Fermi GBM observation
- LIGO/Virgo G211117: INAF VST-ESO PARANAL observations
- LIGO/Virgo G211117: Further Swift-XRT sources
- GRB 151228A: Swift detection of a short burst
- LIGO/Virgo G211117: Identification of a GW CBC Candidate
- GRB 151212A iTelescope observation
- V404Cyg Swift Trigger 668097:
- GRB 151216A: MAXI/GSC detection
- GRB151215A: Early optical light curve from pt5m, La Palma
- GRB 151215A: MASTER early OT detection and light curve
- GRB 151215A: Swift detection of a burst
- GRB 151212A: GROND Optical Afterglow Candidate
- GRB 151212A: Swift-XRT afterglow detection
- GRB 151212A: MAXI/GSC detection
- GRB 151210A: GROND Afterglow Confirmation
- GRB 151210A: Optical afterglow candidate from LCOGT-Cerro Tololo
- GRB 151210A: Swift detection of a burst
- GRB 151205C: Optical follow-up observations at Kiso
- Swift detection of 4U 1850-03
- GRB 130831A: MASTER early OT detection and LC
- Fermi GBM trigger 470375959/151128166 is not a GRB
- GRB 151118A iTelescope observation
- GRB 151118A: Early optical limit from pt5m, La Palma
- GRB 151118A: ISON-NM early optical limit
- GRB GRB 151118A: MASTER-NET optical observations
- GRB 151118A: Optical observations from OSN
- GRB 151118A: Swift detection of a burst
- GRB 151114A: Swift/UVOT Detection
- GRB 151114A: Swift detection of a burst with an optical counterpart
- GRB 151112A: MAXI/GSC detection
- GRB 151111A: GROND marginal detection of a afterglow candidate
- GRB 151111A: LCOGT-FTS afterglow observations
- LIGO/Virgo G194575: La Silla QUEST, Pan-STARRS and PESSTO observations of iPTF15dld
- LIGO/Virgo G194575: VLA follow-up
- LIGO/Virgo G194575: INAF-TNG follow-up of iPTF15dkm and iPTF15dlj
- GRB 151027A: MAXI/GSC detection
- Konus-Wind observation of GRB 151027A
- GRB 151027B: VLT/X-shooter redshift
- LIGO/Virgo G194575: iPTF Optical Transient Candidates
- GRB 151027A: Early RAPTOR Observations
- LIGO/Virgo G194575: MASTER Optical Inspection
- GRB 151027A: Fermi GBM observation
- GRB 151027A : ISON-NM early optical detection
- GRB 151027A: Swift detection of a burst with a bright optical afterglow
- GRB 151021A: Skynet PROMPT-CTIO/DSO17 observations of the optical afterglow
- LIGO/Virgo G194575: Kanata/J-GEM optical follow-up
- GRB 151023A
- LIGO/Virgo G194575: LOFAR follow-up
- LIGO/Virgo G184098: Further VST-ESO PARANAL observations
- LIGO/VIRGO G184098 : PESSTO classification of PS15cbm in the northern region
- LIGO/Virgo G184098: ongoing Pan-STARRS search for optical transients
- LIGO/Virgo G184098: ongoing Pan-STARRS search for optical transients
- IPN Triangulation of GRB 150919A (short / hard)
- LIGO/Virgo G184098: Pan-STARRS1 observations of the northern sky region
- LIGO/Virgo G184098: Observations from the TOROS collaboration
- LIGO/Virgo G184098: iPTF Optical Transient Candidates
- LIGO/Virgo G184098: Swift follow-up observations
- GRB 150910A: TSHAO optical observations
- GRB 150915A: MASTER-NET optical observations
- GRB 150911A: Khureltogot upper limit
- GRB 150911A: WHT optical imaging
- GRB150911A: P60 Observations
- GRB150911A MITSuME Okayama Ks-band upper-limit
- GRB 150910A: MITSuME Okayama Ks-band Observation
- GRB 150910A: SAO RAS optical photometry
- GRB 150907B: GROND Upper Limits
- ANTARES neutrino Alert150901.32 alert and Swift XRT counterpart: MASTER optical observations and new possible candidate
- IPN Triangulation of GRB 150824A
- Swift Trigger 652824: Is most likely a noise fluctuation in the direction of M31
- GRB 150818A: Continued NOT monitoring - afterglow confirmation
- IPN Triangulation of GRB 150819B (short / very intense)
- GRB 150817A: LCOGT observations
- GRB 150817A: Swift-BAT refined analysis
- GRB 150817A: Enhanced Swift-XRT position
- GRB 150817A: Continued RATIR Observations, Revised Candidate
- GRB 150817A: Swift detection of a burst
- GRB 150801A: MAXI/GSC detection
- GRB 150724B: Swift-XRT afterglow detection
- GRB 150727A: Swift detection of a burst with an optical counterpart
- GRB 150724B: Swift-XRT observations
- GRB 150725A: MAXI/GSC detection
- Swift IGR J00291+5934: MASTER Optical flare detection
- GRB 150711A: Swift detection of a burst
- Swift-XRT observations of GRB 150710A
- GRB 150702A: MASTER-SAAO inspection
- GRB 150702A: Swift-XRT observations
- GRB 150608A: Swift-XRT follow-up observations
- GRB 150608A: MITSuME Akeno optical upper limits
- GRB150607A: Discovery Channel Telescope Optical Observations
- GRB 150518A: possible SN observations
- Swift Trigger 642453: a possible GRB
- GRB 150512A: iPTF Optical Observations
- Konus-Wind observation of GRB 150510A
- GRB 150510A: Fermi GBM detection
- GRB 150510A: Fermi-LAT detection
- Confirmation that Swift Trigger 639636 is not astrophysical
- GRB 150430A: MAXI/GSC detection
- GRB 150428B: IRSF NIR upper limits
- GRB 150428B: MASTER-net prompt optical observation
- GRB 150428C/MAXI J0400+678: MAXI/GSC detection