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"5833 results found.
- LIGO/Virgo S200208q: no counterpart candidate in SVOM/C-GFT observations
- LIGO/Virgo S200213t: NED Galaxies in the 90% Localization Volume
- LIGO/Virgo S200208q: No counterpart candidates in KAIT observations
- LIGO/Virgo S200208q: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200208q: Upper limits from IceCube neutrino searches
- LIGO/Virgo S200208q: Identification of a GW compact binary merger candidate
- Fermi trigger No 602817262: Global MASTER-Net observations report
- GRB 200205B: Swift detection of a burst with optical counterpart
- GRB200120A: SRG/eROSITA discovery of X-ray afterglow
- GRB 200205A: Swift detection of a burst with a possible UV counterpart
- Fermi trigger No 602455182: Global MASTER-Net observations report
- GRB 200131A: Swift detection of a burst with an optical counterpart
- Konus-Wind observation of GRB 200130B
- IPN triangulation of GRB 200130B
- LIGO/Virgo S200128d: no counterpart candidate in SVOM/GWAC observations
- LIGO/Virgo S200128d : No significant candidates in FRAM - TAROT - GRANDMA observations
- GRB 200130B: BALROG localization (Fermi Trigger 602071201 / GRB 200130417)
- GRB 200130B: Fermi GBM Final Real-time Localization
- LIGO/Virgo S200129m: Global MASTER-Net observations report
- GRB 200129A: Fermi GBM Final Real-time Localization
- LIGO/Virgo S200128d: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200128d: No counterpart candidates in KAIT observations
- Fermi-LAT-ANTARES coincidence
- LIGO/Virgo S200128d: Coverage and upper limits from MAXI/GSC observations
- GRB 200127A: AbAO optical upper limit
- Fermi trigger No 601729856: Global MASTER-Net observations report
- Fermi trigger No 601677816: Global MASTER-Net observations report
- GRB 200125A: Swift detection of a burst
- LIGO/Virgo S200114f : No significant candidates in TAROT - FRAM - GRANDMA observations
- Fermi trigger No 601363105: Global MASTER-Net observations report
- GRB 191031D: XMM-Newton upper limit
- LIGO/VIRGO S200115j: No obvious candidates from Pan-STARRS2 observations
- IceCube 200117A: No significant detection in HAWC
- LIGO/Virgo S200115j : No significant candidates in TAROT - FRAM - GRANDMA observations
- LIGO/Virgo S200105ae: More candidates from the Zwicky Transient Facility
- LIGO/Virgo S200114f: More candidates from the Zwicky Transient Facility
- IceCube Alert 200117.46: Global MASTER-Net observations report
- LIGO/Virgo S200112r : No significant candidates in TAROT - FRAM - GRANDMA observations.
- LIGO/Virgo S200115j: No neutrino candidates at Pierre Auger Observatory
- LIGO/Virgo S200115j: no counterpart candidate in SVOM/GWAC observations
- Baksan Neutrino Observatory Alert 200116.21: Global MASTER-Net observations report
- IPN triangulation of GRB 200111A
- LIGO/Virgo S200115j: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200114f: No counterpart in targeted WHT/ACAM imaging
- LIGO/Virgo S200115j: INTEGRAL was inactive at the time of the event
- LIGO/Virgo S200115j : no neutrino counterpart candidate in ANTARES search
- GRB 200114A: DDOTI/OAN optical observations report
- LIGO/Virgo S200114f: No Counterparts in DDOTI/OAN Optical Observations
- LIGO/Virgo S200114f: upper limits from AGILE-GRID observations
- LIGO/Virgo S200114f: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S200114f: Identification of a GW unmodeled transient candidate
- Fermi-LAT Gamma-ray Observations of IceCube-200109A and detection of a possible new gamma-ray source, Fermi J1055.8+1034
- IceCube 200109A: No significant detection in HAWC
- Fermi-LAT ANTARES coincidence: No significant detection in HAWC
- Fermi trigger No 600448273: Global MASTER-Net observations report
- IceCube-200107A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-200109A: INTEGRAL was inactive at the time of the event
- IceCube-200109A: IceCube observation of a high-energy neutrino candidate event
- IceCube Alert 200109.99: Global MASTER-Net observations report
- IceCube Alert 200109.99: Global MASTER-Net observations report
- LIGO/Virgo S200105ae : No significant candidates in TAROT - FRAM - GRANDMA observations.
- Fermi-LAT ANTARES coincidence /ANTARES alert 200108.39: MASTER alert and inspect observation
- Fermi-LAT ANTARES coincidence: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- Fermi trigger No 600227156: Global MASTER-Net observations report
- Swift GRB200109.07: Global MASTER-Net observations report
- GRB 200109A: Swift detection of a burst
- Fermi-LAT ANTARES coincidence: Upper limits from Fermi-GBM Observations
- Fermi-LAT ANTARES coincidence
- Fermi-LAT Gamma-ray Observations of IceCube-200107A
- IceCube-200107A: No significant detection in HAWC
- IceCube-200107A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- IceCube-200107A: IceCube observation of a high-energy neutrino candidate event
- LIGO/Virgo S200105ae: Global MASTER-Net observations report
- Fermi trigger No 599761015: Global MASTER-Net observations report
- IceCube Alert 200101.46: Global MASTER-Net observations report
- Fermi trigger No 599603971: Global MASTER-Net observations report
- GRB 191228A: Mondy optical upper limit
- IPN triangulation of GRB 191227B (short)
- LIGO/Virgo S191225aq: Global MASTER-Net observations report
- 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: ALMA detection
- GRB 191221B: Swift-BAT refined analysis
- LIGO/Virgo S191213g : No significant candidates found in GRANDMA citizen science observations
- GRB 191221B: Enhanced Swift-XRT position
- Baksan Neutrino Observatory Alert 191222.09: Global MASTER-Net observations report
- GRB 191221B: Swift detection of a burst and a very bright optical candidate
- LIGO/Virgo S191216ap: MASTER optical observation
- LIGO/Virgo S191216ap : No significant candidates in FRAM-TAROT-GRANDMA observations
- LIGO/Virgo S191213g : SAO 1-m optical observation of AT2019wxt (PS19hgw)
- LIGO/Virgo S191213g: No counterpart candidate in the NOWT observations
- LIGO/Virgo S191216ap: No candidates found in CHES observations of HAWC error region
- LIGO/Virgo S191216ap: IceCube event: MASTER OF detection in GW and Neutrino error field
- LIGO/Virgo S191215w : No significant candidates in TAROT - FRAM - GRANDMA observations.
- LIGO/Virgo G191216ap: No counterpart candidates in Fermi-LAT observations
- Fermi-LAT Gamma-ray Observations of IceCube-191215A
- IceCube-191215A: Upper limits from a search for additional neutrino events in IceCube
- UKIRT photometry of ZTF19acyldun/AT 2019wrt