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"
6098 results found.
- GRB 200227A: Swift-XRT refined Analysis
- GRB 200227A: Fermi GBM observation
- IceCube-200227A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- 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
- LIGO/Virgo S200225q: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200225q: upper limits from AGILE/MCAL observations
- 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 S200224ca: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S200224ca: upper limits from AGILE/MCAL observations
- GRB 200219C: Swift-XRT afterglow confirmation
- GRB 200224A: Swift-XRT refined Analysis
- GRB 200219C: OAJ afterglow confirmation
- GRB 200219C: Swift-XRT afterglow detection
- GRB 200219C: Fermi GBM detection
- LIGO/Virgo S200213t: Swift UVOT and XRT observations of ZTF20aamvmzj (AT2020cja)
- GRB 200219C: Fermi-LAT detection
- GRB 200219A, Swift-BAT refined analysis
- LIGO/Virgo S200219ac: No counterpart candidates in Fermi-LAT observations
- GRB 200219A: Swift-XRT refined Analysis correction
- GRB 200219A: Swift-XRT refined Analysis
- GRB 200219A: Fermi GBM observation
- LIGO/Virgo S200219ac: upper limits from AGILE/MCAL observations
- LIGO/Virgo S200219ac: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- GRB 200216B: Swift-XRT refined Analysis
- Further Swift-XRT observations of Swift J0840.7-3516
- GRB 200215A: Swift-XRT refined Analysis
- GRB 200215A: Fermi GBM detection
- LIGO/Virgo S200213t: No candidates found in J-GEM follow-up observations
- LIGO/Virgo S200213t: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200213t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- ZTF20aajnksq: Upper limits from Konus-Wind observations
- LIGO/Virgo S200208q: No counterpart candidates in Fermi-LAT observations
- GRB 200120A: Fermi GBM observation
- LIGO/Virgo S200208q: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 200205B: ESO/NTT near-infrared imaging
- GRB 200205B: Swift-XRT refined Analysis
- Swift GRB200205.81: Global MASTER-Net observations report
- Swift GRB200205.81: Global MASTER-Net OT detection
- LIGO/Virgo S200129m: Upper limits from Konus-Wind observations
- LIGO/Virgo S200128d: Upper limits from Konus-Wind observations
- GRB 200131A: Swift-XRT refined Analysis
- LIGO/Virgo S200129m: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200128d: upper limits from AGILE/GRID observations
- LIGO/Virgo S200129m: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S200128d: No counterpart candidates in Fermi-LAT observations
- GRB 200127A: Swift/UVOT Upper Limits
- LIGO/Virgo S200128d: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 200127A: Swift-XRT refined Analysis
- GRB 200125A: Swift-BAT refined analysis
- GRB 200125A: Further Swift-XRT observations
- GRB 200125B: Fermi GBM observations
- GRB 200125A: TNG detection of a NIR counterpart candidate
- Correction to GRB 200125A: Swift-XRT refined analysis
- GRB 200125A: Swift-XRT refined Analysis
- LIGO/Virgo S200115j: Zwicky Transient Facility search for optical counterparts to Swift X-ray sources
- LIGO/Virgo S200115j: Further Swift-XRT sources
- GRB 200122A: Swift-XRT refined Analysis
- Fermi-LAT Gamma-ray Observations of IceCube-200120A
- LIGO/Virgo S200115j: Upper limits from Konus-Wind observations
- LIGO/Virgo S200114f: Upper limits from Konus-Wind observations
- LIGO/Virgo S200112r: Upper limits from Konus-Wind observations
- GRB 191031D: XMM-Newton upper limit
- IceCube-200120A: no counterpart candidates in INTEGRAL SPI-ACS and,IBIS prompt observation
- LIGO/Virgo S200105ae: Upper limits from Konus-Wind observations
- LIGO/Virgo S191222n: Upper limits from Konus-Wind observations
- LIGO/Virgo S191216ap: Upper limits from Konus-Wind observations
- LIGO/Virgo S191215w: Upper limits from Konus-Wind observations
- IceCube 200117A: No significant detection in HAWC
- LIGO/Virgo S191213g: Upper limits from Konus-Wind observations
- LIGO/Virgo S191205ah: Upper limits from Konus-Wind observations
- LIGO/Virgo S191204r: Upper limits from Konus-Wind observations
- LIGO/Virgo S191129u: Upper limits from Konus-Wind observations
- Fermi-LAT Gamma-ray Observations of IceCube-200117A
- LIGO/Virgo S200115j: LCO upper limits for ZTF20aafqvyc/AT2020yq from the McDonald Observatory 1-m telescope
- LIGO/Virgo S200115j: NIR upper limits for ZTF20aafqvyc/AT2020yq from the Palomar 200-inch telescope
- IceCube-200117A: no counterpart candidates in INTEGRAL SPI-ACS and,IBIS prompt observation
- LIGO/Virgo S200114f: No transients found in J-GEM observations of nearby galaxies
- LIGO/Virgo S200115j: Swift-XRT sources
- LIGO/Virgo S200114f: Swift-XRT sources and observations
- LIGO/Virgo S200115j: No counterpart candidates in Fermi-LAT observations
- GRB 200115A: Nanshan-0.6m optical upper limit
- GRB 200115A: Swift detection of a burst
- LIGO/Virgo S200114f: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200114f: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- 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
- IceCube 200109A: No significant detection in HAWC
- Fermi-LAT ANTARES coincidence: No significant detection in HAWC
- GRB 200109A: Fermi GBM observation
- GRB 200107B: Swift-XRT refined Analysis
- Fermi-LAT ANTARES coincidence: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- GRB 200109A: Swift-XRT refined Analysis
- GRB 200107B: Fermi GBM observation
- 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
- LIGO/Virgo 200105ae: No counterpart candidates in Fermi-LAT observations