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"28041 results found.
- LIGO/Virgo S200225q: AstroSat CZTI upper limits
- LIGO/Virgo S200219ac: AstroSat CZTI upper limits
- LIGO/Virgo S200302c: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S200302c: Upper limits from IceCube neutrino searches
- LIGO/Virgo S200302c: Identification of a GW compact binary merger candidate
- GRB 200228B: Mondy, TSHAO, AbAO and CrAO optical observations, afterglow candidate
- LIGO/Virgo S200225q : No significant candidates in TAROT - FRAM - GRANDMA observations.
- GRB 200228B: LCO Optical Upper Limit
- GRB 200228B: Swift-BAT refined analysis
- GRB 200228B: RATIR Optical Observations
- GRB 200228B: Liverpool Telescope imaging
- GRB 200228B: Swift-XRT refined Analysis
- GRB 200228B: Swift/UVOT Upper Limits
- GRB 200228B: RATIR Optical Observations
- GRB 200228B: Fermi GBM observation
- GRB 200227A: RATIR Optical Observations
- IceCube-200227A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo S200224ca: Updated Sky Localization and EM Bright Classification
- GRB 200228C: Insight-HXMT/HE detection
- GRB 200228A: Fermi GBM observation
- GRB 200227A: Mondy optical upper limit
- GRB 200228B: Enhanced Swift-XRT position
- Fermi-LAT Gamma-ray Observations of IceCube-200227A
- GRB 200228B: Swift detection of a burst
- GRB 200227A: Insight-HXMT/HE detection
- IceCube-200227A : Upper limits from Insight-HXMT/HE observations
- GRB 200227A: Swift-XRT refined Analysis
- GRB 200228A: BALROG localization (Fermi Trigger 604565918 / GRB 200228291)
- GRB 200227A: Swift-BAT refined analysis
- GRB 200227A: Swift/UVOT Upper Limits
- GRB 200227A: Enhanced Swift-XRT position
- HAWC-200216A: No Neutrino Counterpart in ANTARES Search
- GRB 200224A: Mondy optical upper limit
- GRB 200227A: Fermi GBM observation
- LIGO/Virgo S200224ca : No significant candidates in TAROT - FRAM - GRANDMA observations
- IceCube-200227A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- GRB 200227A: Swift detection of a burst
- LIGO/Virgo S200224ca: Upper limits from CALET observations.
- LIGO/Virgo S200224car: GRAWITA VST-ESO PARANAL observations.
- LIGO/Virgo S200225q: Updated Sky Localization
- LIGO/Virgo S200219ac: Upper limits from Konus-Wind observations
- LIGO/Virgo S200213t: Upper limits from Konus-Wind observations
- LIGO/Virgo S200208q: Upper limits from Konus-Wind observations
- GRB 200224A: Calar Alto 2.2m optical afterglow detection
- LIGO/Virgo S200225q: no counterpart candidate in SVOM/GWAC observations
- LIGO/Virgo S200225q: Upper limits from Insight-HXMT/HE observations
- LIGO/Virgo S200224ca: Upper limits from Insight-HXMT/HE observations
- LIGO/Virgo S200225q: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S200224ca: no counterpart candidates in the Swift/BAT observations
- GRB 200224B: DDOTI/OAN optical observations report
- LIGO/Virgo S200219ac: Updated Sky Localization
- LIGO/Virgo S200224ca: No Counterparts in DDOTI/OAN Optical Observations
- LIGO/Virgo S200224ca: GRAWITA-Campo Imperatore observations.
- LIGO/Virgo S200225q: Upper limits from Fermi-GBM Observations
- LIGO/Virgo S200225q: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200225q: upper limits from AGILE/GRID observations
- LIGO/Virgo S200224ca: Subaru/Hyper Suprime-Cam follow-up observations
- LIGO/Virgo S200225q: upper limits from AGILE/MCAL observations
- LIGO/Virgo S200225q: Upper limits from IceCube neutrino searches
- LIGO/Virgo S200225q: No counterpart candidates in HAWC observations
- LIGO/Virgo S200225q : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S200224ca: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200225q: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- LIGO/Virgo S200225q: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S200219ac: No counterpart candidates from Nanshan/NEXT observations
- LIGO/Virgo S200224ca: upper limits from AGILE/GRID observations
- GRB 200224A: Swift-BAT refined analysis
- LIGO/Virgo S200225q: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration
- GRB 200224A: LCO Upper Limits
- LIGO/Virgo S200224ca: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 200224A: RATIR Optical Observations and Confirmation of the Afterglow
- LIGO/Virgo S200224ca: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S200224ca: upper limits from AGILE/MCAL observations
- LIGO/Virgo S200224ca: Upper limits from IceCube neutrino searches
- LIGO/Virgo S200224ca: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration
- GRB 200224A: Swift/UVOT Detection
- GRB 200224A: Swift-XRT refined Analysis
- GRB 200224A: Tautenburg observations
- GRB 200224A: BOOTES-1 and 1.5m OSN optical observations
- GRB 200224A: Swift detection of a burst
- LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC-F30 observations
- LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC observations
- LIGO/Virgo S200219ac : No significant candidates in TAROT - FRAM - GRANDMA observations.
- GRB 200219C: OAJ afterglow confirmation
- GRB 200219A: UVOT Upper Limits
- GRB 200219C: Mondy and TSHAO optical observations
- GRB 200219C: Nanshan/NEXT optical upper limit and possible host galaxy from PanSTARRS
- GRB 200219C: Swift-XRT afterglow detection
- GRB 200219C: DDOTI Observations
- GRB 200219C: Fermi GBM detection
- LIGO/Virgo S200213t: Swift UVOT and XRT observations of ZTF20aamvmzj (AT2020cja)
- GRB 200215A: LCO Optical Upper Limits
- GRB 200219A, Swift-BAT refined analysis
- LIGO/Virgo S200219ac: no counterpart candidates in the Swift/BAT observations
- Fermi trigger No 603849435: Global MASTER-Net observations report
- LIGO/Virgo S200219ac: Fermi GBM transient event not confidently associated with GW signal
- LIGO/Virgo S200219ac: No counterpart candidates in Fermi-LAT observations
- GRB 200219A: Swift-XRT refined Analysis correction
- LIGO/Virgo S200219ac: upper limits from AGILE/GRID observations
- GRB 200219A: Enhanced Swift-XRT position