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.
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"
3927 results found.
- LIGO/Virgo G275697: LOFAR follow-up
- LIGO/Virgo G277583: Konus-Wind observations
- LIGO/Virgo G277583: Fermi GBM Observations
- LIGO/Virgo G277583: INTEGRAL search for an X-ray and gamma-ray counterpart
- LIGO/Virgo G275697: AMI Large Array Search for a Radio Afterglow
- IPN Triangulation of GRB 170320A (long/intense)
- LIGO/Virgo G277583: CALET Observations
- LIGO/Virgo G277583: Asiago spectroscopic classification of ATLAS17byo and ATLAS17cgg
- LIGO/Virgo G277583 : MAXI/GSC observations
- LIGO/Virgo G275404: P200/DBSP Classification of iPTF Candidates
- LIGO/Virgo G277583: P200/DBSP Classification of ATLAS Candidates
- LIGO/Virgo G277583: AstroSat CZTI upper limits
- LIGO/Virgo G275697: Swift-XRT source 23 no longer fading
- LIGO/Virgo G277583: Swift/BAT data search
- LIGO/Virgo G277583: Discovery Channel Telescope Follow-Up of ATLAS17cck
- LIGO/Virgo G277583: ATLAS coverage and transients over the first 2 days
- LIGO/Virgo G277583: ATLAS17cck is likely a minor planet
- LIGO/Virgo G277583: GROND follow up of ATLAS17cck
- LIGO/Virgo G277583: ATLAS17cck - a fast declining transient
- LIGO/Virgo G275697: DLT40 follow-up observation
- LIGO/Virgo G274296: DLT40 follow-up observation
- LIGO/Virgo G275697: Fermi-LAT search for a high-energy gamma-ray counterpart
- LIGO/Virgo G277583: ERRATUM LV GCN 20871: TAROT Calern (TCA) observations
- LIGO/Virgo G277583: TAROT Calern (TCA) observations
- LIGO/Virgo G277583: SVOM/Mini-GWAC observations of the initial skymap
- LIGO/Virgo G275404: Medicina radio follow-up of near-infrared
- LIGO/Virgo G277583: INTEGRAL was inactive at the time of the event
- LIGO/Virgo G277583 ANTARES search
- LIGO/Virgo G277583: AGILE GRID observations
- LIGO/Virgo G277583: AGILE MCAL observations
- LIGO/Virgo G270580: optical observations and classification of PS and MASTER sources
- LIGO/Virgo G277583: IceCube neutrino observations
- LIGO/Virgo G277583: Identification of a GW Burst Candidate
- IPN Triangulation of GRB 170311B (long/very intense)
- LIGO/Virgo G275697: GRAWITA NOT optical observations of Swift/XRT Source 23
- SN MASTER OT J042250.16-820415.4 is the possible optical counterpart of the gravitational waves event LIGO/Virgo G274296
- LIGO/Virgo G275404: Swift-XRT observations of sources in the AGILE error region
- LIGO/Virgo G275697: Swift-XRT source 23 is fading
- LIGO/Virgo G275404: Updated localization from LIGO data
- LIGO/Virgo G275404 and AGL J1914+1043: INTEGRAL follow-up
- LIGO/Virgo G275697: Updated localization from LIGO data
- LIGO/Virgo G275697: Further Swift-XRT sources
- LIGO/Virgo G275697: P200/DBSP Classification of iPTF Candidates
- LIGO/Virgo G275404: P200/DBSP Classification of iPTF Candidates
- LIGO/Virgo G275697: Liverpool Telescope classification of EM candidates
- LIGO/Virgo G275404: Liverpool Telescope classification of EM candidates
- LIGO/Virgo G275697: Further Swift-XRT sources
- LIGO/Virgo G275404: HAWC follow-up
- LIGO/Virgo G275404: PIRATE Observations
- LIGO/Virgo G275404: Liverpool Telescope classification of EM candidates
- LIGO/Virgo G275697: Liverpool Telescope classification of EM candidates
- LIGO/Virgo G275697: Further Swift-XRT sources
- LIGO/Virgo G275697: MAXI/GSC observations
- LIGO/Virgo G275697: Additional iPTF Optical Transient Candidates
- LIGO/Virgo G275404: Additional iPTF Optical Transient Candidates
- LIGO/Virgo G275404: Nearby Galaxies in the Localization Volume
- LIGO/Virgo G275697: Further Swift-XRT sources
- LIGO/Virgo G275697: Fermi GBM Upper Limits
- LIGO/Virgo G275697: AstroSat CZTI upper limits
- LIGO/Virgo G275697: optical spectroscopy of Swift/XRT source 1
- LIGO/Virgo G268556, G270580, G274296, and G275404: Konus-Wind observations
- LIGO/Virgo G275697: SVOM/Mini-GWAC observations of the initial skymap
- LIGO/Virgo G275697: iPTF Optical Transient Candidates
- LIGO/Virgo G275404: iPTF Optical Transient Candidates
- LIGO/Virgo G275404: Fermi GBM Upper Limits
- LIGO/Virgo G275404: A near-infrared transient in the error circle of AGL J1914+1043
- LIGO/Virgo G275697: CALET Observations
- LIGO/Virgo G275697: MASTER automatic follow up detection
- LIGO/Virgo G275697: CNEOST optical observations
- LIGO/Virgo G274296 and G275404 : MAXI/GSC observations
- LIGO/Virgo G275404: Nearby galaxy observations by J-GEM collaboration
- LIGO/Virgo G275404: Nearby Galaxies in the Localization Region
- LIGO/Virgo G275697: Fermi-LAT search for a high-energy gamma-ray counterpart
- LIGO/Virgo G275697: REM optical/NIR observations
- LIGO/Virgo G275697: Konus-Wind observations
- LIGO/Virgo G275404: CNEOST optical observations
- LIGO/Virgo G275697: Swift-XRT sources
- LIGO/Virgo G275697: Swift/BAT data search
- LIGO/Virgo G275404: MASTER bright PSN detected on 27 Feb from the maximum of probability of LIGO localization
- LIGO/Virgo G275697: AGILE-GRID preliminary analysis
- LIGO/Virgo G275697: AGILE MCAL Observations
- LIGO/Virgo G275697: INTEGRAL search for a prompt gamma-ray counterpart
- LIGO/VIRGO G275697: Fermi GBM Observations
- LIGO/Virgo G275404: AstroSat CZTI upper limits
- LIGO/Virgo G275697 ANTARES search
- LIGO/Virgo G275697: IceCube neutrino observations
- LIGO/Virgo G275697: Identification of a GW CBC Candidate
- LIGO/Virgo G275404: Keck LRIS classification of MASTER PSN candidate
- LIGO/Virgo G274296: MASTER new PSN detected on 22 feb
- LIGO/Virgo G275404: REM optical/NIR observations
- LIGO/Virgo G275404: MASTER PSN detection from the maximal probability LIGO region
- LIGO/Virgo G275404: MASTER OT is outside LIGO error region
- LIGO/Virgo G275404: Keck spectrum of MASTER OT J105958.00-115756.5
- LIGO/Virgo G275404: Fermi-LAT search for a high-energy gamma-ray counterpart
- LIGO/Virgo G275404: INTEGRAL search for a prompt gamma-ray counterpart
- LIGO/Virgo G275404: AGILE-GRID detection of a possible gamma-ray transient
- LIGO/Virgo G275404: NOT Follow-up of MASTER OT
- LIGO/Virgo G275404: Swift-XRT sources
- LIGO/Virgo G275404 ANTARES search
- LIGO/Virgo G275404: Follow-up of MASTER OT J173532.70+103810.5