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"4055 results found.
- GRB 220107A: Swift/BAT-GUANO arcminute localization
- GRB 211229A: Swift/BAT-GUANO arcminute localization
- IPN triangulation of GRB 211130A
- GRB 211023A: optical observations and photometric evidence of supernova
- GRB 211107B: Swift/BAT detection
- GRB 211106A: Swift/BAT-GUANO candidate arcminute localization of a short burst
- GCN Viewer Now Available
- GRB 211024A: Swift/BAT-GUANO detection and candidate arcminute localization of a short burst
- IPN triangulation of GRB 210925B
- IPN triangulation of a bright burst from SGR 1935+2154
- GRB 210619B: Maidanak and Assy optical observations, broken power law parametrization
- GRB 210827A: Swift/BAT-GUANO detection and arcminute localization
- IPN Triangulation of a bright burst from SGR 1935+2154
- GRB 210706A: Swift/BAT-GUANO detection and arcminute localization
- GRB 210619B: Deep CAHA 2.2m detection and late-time light curve behavior
- GRB 210626A: Swift/BAT-GUANO detection and arcminute localization
- IPN triangulation of GRB 210624A (short)
- GRB 210622A: Swift/BAT-GUANO detection and arcminute localization of a long burst
- GRB 210610A: CAHA 2.2m observations and light-curve behavior
- GRB 210610B: University of Siena Observatory optical photometry of the afterglow
- GRB 210606A: Swift/BAT-GUANO detection and arcminute localization
- GRB 210506A: Swift/BAT-GUANO detection and possible arcminute localization of a short hard burst
- IPN triangulation of GRB 210424B (short/hard)
- GRB 210421B: Swift/BAT-GUANO detection and arcminute localization
- GRB 210413B: Swift/BAT detection and probable localization of a short burst
- GRB210410A: Joint inspection of RATIR and D50 data
- GRB 210323B: Swift/BAT-GUANO detection and possible arcminute localization
- IceCube-201221A: Upper limits from Insight-HXMT/HE observations
- GRB 201216A: Swift/BAT-GUANO detection and arcminute localization
- IceCube-201209A: Upper limits from Insight-HXMT/HE observations
- GRB 201128B: Swift/BAT-GUANO detection and arcminute localization
- GRB 201104C: Fermi GBM Final Real-time Localization
- GRB 201104A: Tiled Swift observations
- GRB 201103B: AGILE detection
- GRB 201104A: AGILE/MCAL detection
- GRB 201104A: Fermi-LAT detection
- GRB 201008A: Swift/BAT-GUANO detection and possible arcminute localization
- GRB 200809B: Swift/BAT-GUANO detection and arcminute localization
- GRB 200714E: Swift/BAT-GUANO detection and arcminute localization
- GRB 200623A: Swift/BAT-GUANO detection and arcminute localization of a short GRB
- LIGO/Virgo MS200618aq: Retraction of a test binary neutron star candidate
- LIGO/Virgo MS200619bf: Retraction of a test binary neutron star candidate
- LIGO/Virgo MS200618bx: Retraction of a test binary neutron star candidate
- LIGO/Virgo MS200618bq: Retraction of a test binary neutron star candidate
- LIGO/Virgo MS200614ct: Identification of a test binary black hole candidate
- LIGO/Virgo MS200615ce: Identification of a test binary black hole candidate
- LIGO/Virgo MS200614bz: Test Identification of a binary neutron star candidate
- LIGO/Virgo MS200615h: Retraction of a test binary neutron star candidate
- IPN triangulation of GRB 200415A (possible Magnetar Giant Flare in Sculptor Galaxy?)
- IceCube-200410A : Upper limits from Insight-HXMT/HE observations
- IPN Triangulation of a bright burst from SGR 1935+2154
- LIGO/Virgo S200225q: Swift XRT observations, 1 X-ray sources
- LIGO/Virgo S200224ca: Swift XRT observations, 8 X-ray sources
- GRB 200405B: Swift/BAT-GUANO detection and *possible* arcminute localization of a short GRB
- LIGO/Virgo S200316bj: Upper limits from Konus-Wind observations
- LIGO/Virgo S200311bg: Upper limits from Konus-Wind observations
- LIGO/Virgo S200302c: Upper limits from Konus-Wind observations
- LIGO/Virgo S200225q: Upper limits from Konus-Wind observations
- LIGO/Virgo S200224ca: Upper limits from Konus-Wind observations
- IPN triangulation of GRB 200327A (short)
- LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC-F30 observations
- LIGO/Virgo S200316bj: Updated Sky Localization and EM Bright Classification
- LIGO/Virgo S200316bj : No significant candidates in TAROT - FRAM - GRANDMA observations.
- LIGO/Virgo S200316bj: Upper limits from Insight-HXMT/HE observations
- LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC observations
- LIGO/Virgo S200316bj: Upper limits from CALET observations
- LIGO/Virgo S200316bj: No neutrino candidates at Pierre Auger Observatory
- LIGO/Virgo S200316bj: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200316bj: No Counterparts in DDOTI/OAN Optical Observations
- LIGO/Virgo S200316bj: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S200213t: Continued Swift UVOT and XRT observations of ZTF20aamvmzj (AT2020cja)
- LIGO/Virgo S200316bj: No counterpart candidates in INTEGRAL SPI-ACS, and IBIS prompt observation
- LIGO/Virgo S200316bj: upper limits from AGILE/GRID observations
- LIGO/Virgo S200316bj: upper limits from AGILE/MCAL observations
- LIGO/Virgo S200316bj: Upper limits from Fermi-GBM Observations
- LIGO/Virgo S200316bj: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S200316bj : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S200316bj: Upper limits from IceCube neutrino searches
- LIGO/Virgo S200316bj: Identification of a GW compact binary merger candidate
- LIGO/Virgo S200316bj: Global MASTER-Net observations report
- LIGO/Virgo S200311bg: Updated Sky Localization and EM Bright Classification
- LIGO/Virgo S200311bg: Not observable by CALET
- LIGO/Virgo S200311bg: Swift/BAT in the South Atlantic Anomaly
- LIGO/Virgo S200311bg: No significant counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200224ca: DESGW Summary of DECam Observations
- LIGO/Virgo S200311bg: not observable by Fermi GBM
- LIGO/Virgo S200311bg: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S200311bg: not observable by AGILE at the event time
- LIGO/Virgo S200311bg: No counterpart candidates in INTEGRAL SPI-ACS,prompt observation
- LIGO/Virgo S200311bg: Upper limits from IceCube neutrino searches
- LIGO/Virgo S200311bg: Identification of a GW compact binary merger candidate
- LIGO/Virgo S200308e: Retraction of GW compact binary merger candidate
- LIGO/Virgo S200302c: No notable candidates in GOTO imaging
- LIGO/Virgo S200302c : No significant candidates in FRAM - TAROT - GRANDMA observations.
- LIGO/Virgo S200225q: No notable candidates in GOTO imaging
- LIGO/Virgo S200302c: AstroSat CZTI upper limits
- LIGO/Virgo S200302c: Upper limits from Insight-HXMT/HE observations
- LIGO/Virgo S200303ba: Retraction of GW compact binary merger candidate
- LIGO/Virgo S200302c: No transient candidates in CALET observations
- LIGO/Virgo S200224ca: No counterpart candidates in TOROS observations