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"7450 results found.
- LIGO/Virgo S191216ap: CORRECTED list of galaxies coincident with LIGO/Virgo and HAWC positions
- LIGO/Virgo S191216ap: Nanshan follow-up observations
- LIGO/Virgo S191213g: MASTER OT J064855.37-055545.7 is a dwarf nova
- LIGO/Virgo S191216ap: No Candidates from the Zwicky Transient Facility
- LIGO/Virgo S191216ap: Correction to GCN 26460 (IceCube event coincident with GW event)
- LIGO/Virgo S191216ap: Upper limits from Fermi-GBM Observations
- LIGO/Virgo S191216ap: 1 counterpart neutrino candidate from IceCube neutrino searches
- Fermi-LAT Gamma-ray Observations of IceCube-191215A
- LIGO/Virgo S191216ap : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S191216ap: No counterpart candidates in HAWC observations
- LIGO/Virgo S191216ap: Identification of a GW compact binary merger candidate
- UKIRT photometry of ZTF19acyldun/AT 2019wrt
- LIGO/Virgo S191215w: AstroSat CZTI upper limits
- LIGO/Virgo S191215w: upper limits from AGILE-GRID observations
- LIGO/Virgo S191215w: Upper limits from Fermi-GBM Observations
- LIGO/Virgo S191215w: No counterpart candidates in HAWC observations
- LIGO/Virgo S191215w : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S191215w: Identification of a GW compact binary merger candidate
- LIGO/Virgo S191215w: Upper limits from IceCube neutrino searches
- IceCube-191215A: not observable by Fermi-GBM
- LIGO/Virgo S191213g: Additional candidates from the Zwicky Transient Facility
- IceCube-191215A - IceCube observation of a high-energy neutrino candidate event
- LIGO/Virgo S191213g: LCOGT photometry of ZTF19acymaru/AT2019wnh
- LIGO/Virgo S191213g: WHT spectroscopy of candidate counterparts
- LIGO/Virgo S191213g: GRAWITA TNG classification of ZTF19acykzsk
- LIGO/Virgo S191213g: AstroSat CZTI upper limits
- LIGO/Virgo S191213g: Candidates from the Zwicky Transient Facility
- LIGO/Virgo S191213g: No neutrino candidates at Pierre Auger Observatory
- LIGO/Virgo S191213g: Updated Sky Localization
- LIGO/Virgo S191205ah: Candidates from the Zwicky Transient Facility Public Survey
- LIGO/Virgo S191213ai: Retraction of GW compact binary merger candidate
- LIGO/Virgo S191213g: Upper limits from Fermi-GBM Observations
- LIGO/Virgo S191213g: upper limits from AGILE-GRID observations
- LIGO/Virgo S191213g : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S191213g: Identification of a GW compact binary merger candidate
- LIGO/Virgo S191213g: Upper limits from IceCube neutrino searches
- LIGO/Virgo S191205ah: Gaia Photometric Alerts transient candidates
- LIGO/Virgo S191212q: Retraction of GW compact binary merger candidate
- Possible HAWC-detected GRB 191210A: Fermi-LAT Upper Limits
- Possible HAWC-detected GRB 191210A: no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S191205ah: no counterpart candidate in SVOM/GWAC observations
- LIGO/Virgo S191129u: Updated Sky Localization
- LIGO/Virgo S191205ah: Not observable by CALET
- LIGO/Virgo S191205ah: AstroSat CZTI upper limits
- LIGO/Virgo S191205ah: No neutrino candidates at Pierre Auger Observatory
- LIGO/Virgo S191205ah: GMG detection of SAGUARO transient
- LIGO/Virgo S191205ah: SAGUARO observations and identification of an optical candidate
- LIGO/Virgo S191205ah: Upper limits from Fermi-GBM Observations
- LIGO/Virgo S191205ah: No counterpart candidates in HAWC observations
- LIGO/Virgo S191205ah : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S191205ah: Identification of a GW compact binary merger candidate
- LIGO/Virgo S191205ah: Upper limits from IceCube neutrino searches
- IceCube-191204A: Upper limits from Fermi-GBM Observations
- IceCube-191204A - IceCube observation of a high-energy neutrino candidate event
- LIGO/Virgo S191204r: upper limits from AGILE-GRID observations
- LIGO/Virgo S191204r : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S191204r: Upper limits from IceCube neutrino searches
- LIGO/Virgo S191204r: Identification of a GW compact binary merger candidate
- GRB 191130A: Swift ToO observations
- LIGO/Virgo S191129u: No counterpart candidates in HAWC observations
- LIGO/Virgo S191129u: upper limits from AGILE/GRID observations
- LIGO/Virgo S191129u : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S191129u: Upper limits from IceCube neutrino searches
- LIGO/Virgo S191129u: Identification of a GW compact binary merger candidate
- IceCube-191122A: Not observable by Fermi-GBM
- LIGO/Virgo S191124be: Retraction of GW compact binary merger candidate
- GRB 191123A: Swift/UVOT detection
- GRB 191123A: Swift detection of a burst with an optical counterpart
- IceCube-191122A - IceCube observation of a high-energy neutrino candidate event
- GRB 191122A: CHES Optical Observations
- GRB 191122A: Swift detection of a burst
- IceCube-191119A: No neutrino counterpart candidates in ANTARES search
- LIGO/Virgo S191120at: Retraction of GW compact binary merger candidate
- LIGO/Virgo S191120aj: Retraction of GW compact binary merger candidate
- IceCube-191119A: Upper limits from Fermi-GBM Observations
- IceCube-191119A - IceCube observation of a high-energy neutrino candidate event
- LIGO/Virgo S191117j: Retraction of GW compact binary merger candidate
- Swift Trigger 937114 is not an astrophysical source
- LIGO/Virgo S191110af: Retraction of GW unmodeled transient candidate
- LIGO/Virgo S191110af: Upper limits from KM3NeT MeV neutrino search.
- LIGO/Virgo S191105e: Updated Sky Localization
- LIGO/Virgo S191110af: Potential pulsar counterparts
- LIGO/Virgo S191110af: Upper limits from CALET observations.
- LIGO/Virgo S191109d: Not observable by CALET
- LIGO/Virgo S191110af: Upper limits from IceCube MeV neutrino searches
- LIGO/Virgo S191110af: No neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S191110af: Upper limits from Fermi-GBM Observations
- LIGO/Virgo S191110af: Identification of a GW unmodeled transient candidate
- LIGO/Virgo S191110af: Upper limits from IceCube neutrino searches
- LIGO/Virgo S191110x: Retraction of GW compact binary merger candidate
- LIGO/Virgo S191109d: AstroSat CZTI upper limits
- LIGO/Virgo S191109d : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S191109d: upper limits from AGILE-GRID observations mailed-by:
- LIGO/Virgo S191109d: Upper limits from Fermi-GBM Observations
- LIGO/Virgo S191109d: Upper limits from IceCube neutrino searches
- LIGO/Virgo S191109d: Identification of a GW compact binary merger candidate
- LIGO/Virgo S191105e: AstroSat CZTI upper limits
- LIGO/Virgo S191105e: Not observable by CALET
- LIGO/Virgo S191105e : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S191105e: No counterpart candidates in HAWC observations