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"19549 results found.
- GRB 200115A: Mondy optical afterglow candidate
- LIGO/Virgo S200112r : No significant candidates in TAROT - FRAM - GRANDMA observations.
- LIGO/Virgo S200115j: No neutrino candidates at Pierre Auger Observatory
- LIGO/Virgo S200114f: Swift-XRT sources and observations
- LIGO/Virgo S200115j: no counterpart candidate in SVOM/GWAC observations
- Baksan Neutrino Observatory Alert 200116.21: Global MASTER-Net observations report
- LIGO/Virgo S200115j: no counterpart candidates in the Swift/BAT observations
- IPN triangulation of GRB 200111A
- LIGO/Virgo S200115j: No counterpart candidates in Fermi-LAT observations
- GRB 200115A: Nanshan-0.6m optical upper limit
- LIGO/Virgo S200115j : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S200115j: No counterpart candidates in HAWC observations
- GRB 200114A: DDOTI/OAN optical observations report
- LIGO/Virgo S200114f: No Counterparts in DDOTI/OAN Optical Observations
- LIGO/Virgo S200114f: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S200114f: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200114f: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- LIGO/Virgo S200114f : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S200114f: No counterpart candidates in HAWC observations
- Fermi-LAT Gamma-ray Observations of IceCube-200109A and detection of a possible new gamma-ray source, Fermi J1055.8+1034
- LIGO/Virgo 200112r: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200112r: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S200112r: No counterpart candidates in HAWC observations
- LIGO/Virgo S200112r : no neutrino counterpart candidate in ANTARES search
- IceCube 200109A: No significant detection in HAWC
- Fermi-LAT ANTARES coincidence: No significant detection in HAWC
- IceCube-200109A: Swift-XRT and UVoT Follow-up Observations
- ANTARES 200108A: No detection by Swift-XRT
- GRB 200107B: Swift/UVOT Observations
- GRB 200109A: Swift/UVOT Upper Limits
- LIGO/Virgo S200105ae : No significant candidates in TAROT - FRAM - GRANDMA observations.
- Fermi-LAT ANTARES coincidence: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- GRB 200109A: Enhanced Swift-XRT position
- Swift GRB200109.07: Global MASTER-Net observations report
- GRB 200109A: Swift detection of a burst
- Fermi-LAT ANTARES coincidence
- Fermi-LAT Gamma-ray Observations of IceCube-200107A
- IceCube-200107A: No significant detection in HAWC
- IceCube-200107A: No candidates from the Zwicky Transient Facility
- IceCube-200107A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 200107B: Swift detection of a burst
- LIGO/Virgo 200105ae: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200105ae: No counterpart candidates in HAWC observations
- LIGO/Virgo S200105ae: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S200105ae: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S200105ae : no neutrino counterpart candidate in ANTARES search
- Fermi-LAT Gamma-ray Observations of IceCube-191231A
- IceCube-191231A: No significant detection in HAWC
- IceCube-191231A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- GRB 191228A: Mondy optical upper limit
- IPN triangulation of GRB 191227B (short)
- GRB 191228A: Swift/UVOT Upper Limits
- GRB 191228A: Enhanced Swift-XRT position
- GRB 191228A: UKIRT NIR upper limit
- GRB 191228A: Swift detection of a burst
- GRB 191227A: Marginal detection by Fermi-LAT
- GRB 191227A: MITSuME Akeno optical upper limits
- Swift Trigger 946234 is probably not a GRB
- LIGO/Virgo S191205ah: MASTER OT detection
- LIGO/Virgo S191222n : No significant candidates in FRAM-TAROT-GRANDMA observations
- GRB 191221B: Swift/UVOT Detection
- LIGO/Virgo S191222n: no counterpart candidate in SVOM/GWAC observations
- GRB 191221B: iTelescope T17 detection
- LIGO/Virgo S191216ap: No significant candidates found in Pan-STARRS observations
- GRB 191221B: Zadko observatory - Gingin optical observations
- GRB 191221B: Swift-XRT refined Analysis
- LIGO/Virgo S191213g : No significant candidates found in GRANDMA citizen science observations
- LIGO/Virgo S191222n: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S191222n: No counterpart candidates in Fermi-LAT observations
- GRB 191221B: MASTER VWFC OT yearly detection
- GRB 191221B: Correction to GCN26551 - VIRT OT observation
- GRB 191221B: VIRT Optical Upper Limits
- LIGO/Virgo S191222n : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S191222n: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S191222n: No counterpart candidates in HAWC observations
- GRB 191221B: Enhanced Swift-XRT position
- GRB 191221B: Swift detection of a burst and a very bright optical candidate
- LIGO/Virgo S191216ap: VLA/JAGWAR radio monitoring of the 1-sigma HAWC region
- LIGO/Virgo S191216ap: No radio candidates so far in the VLA/JAGWAR galaxy targeted search
- GRB 191220A: Swift/UVOT Upper Limits
- GRB 191220A: AbAO optical observations
- GRB 191220A: Enhanced Swift-XRT position
- GRB 191220A: SAO RAS possible OT detection
- GRB 191220A: Swift detection of a burst
- LIGO/Virgo S191213g: Palomar 60-inch imaging of AT2019wxt
- LIGO/Virgo S191216ap: No candidates found in J-GEM follow-up observations of HAWC error region
- LIGO/Virgo S191213g: No counterpart candidate in the NOWT observations
- LIGO/Virgo S191213g: No candidates found in J-GEM follow-up observations
- LIGO/Virgo S191216ap: IceCube event: MASTER OF detection in GW and Neutrino error field
- LIGO/Virgo S191216ap: No significant counterpart candidates in SAGUARO observations
- LIGO/Virgo S191215w : No significant candidates in TAROT - FRAM - GRANDMA observations.
- LIGO/Virgo G191216ap: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S191216ap: no counterpart candidates in the Swift/BAT observations
- 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 S191215w: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S191215w: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S191215w: No counterpart candidates in HAWC observations
- LIGO/Virgo S191215w: Coverage and upper limits from MAXI/GSC observations