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.
- Fermi-LAT Gamma-ray Observations of IceCube-190712A
- IceCube-190712A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- GRB 190708B: Swift-XRT observations
- LIGO/Virgo S190707q: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190707q: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observations
- LIGO/Virgo S190706ai: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190701ah: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190706ai: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observations
- GRB 190706B: Swift-XRT refined Analysis
- IceCube-190704A - HAWC follow-up
- Fermi-LAT Gamma-ray Observations of IceCube-190704A and detection of the new gamma-ray source 1WHSP J104516.2+275133
- LIGO/Virgo IceCube-190704A: No counterpart candidates in INTEGRAL SPI- ACS and IBIS prompt observation
- Fermi-LAT Gamma-ray Observations of IceCube-190629A
- GRB 190701A: Swift-XRT refined Analysis
- GRB 190630C: Swift-XRT refined Analysis
- LIGO/Virgo S190701ah: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S190630ag: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190630ag: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 190630B: Swift-XRT refined Analysis
- GRB 190627A: Swift-XRT refined Analysis
- GRB 190627A: Optical imaging and spectroscopy from Calar Alto
- Swift Trigger 911102 is likely not an astrophysical event
- Fermi-LAT Gamma-ray Observations of IceCube-190619A
- IceCube-190619A - HAWC follow-up
- IceCube-190619A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- GRB 190610A: Swift-XRT observations
- GRB 190613B: Swift-XRT refined Analysis
- GRB 190613A: Fermi GBM detection
- GRB 190613B: Fermi GBM observation
- GRB 190613A: Swift-XRT refined Analysis
- GRB 190611B: Fermi GBM detection
- GRB 190611A: Swift-XRT refined Analysis
- GRB 190530A: Further OAJ/OSN photometry and analysis
- GRB 190604B: VLT Afterglow Detection
- GRB 190606A: Fermi-LAT detection
- GRB 190604B: Swift-XRT refined Analysis
- LIGO/Virgo S190602aq: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- LIGO/Virgo S190602aq: No counterpart candidates in Fermi-LAT observations
- GRB 190530A: SAO RAS optical observations
- GRB 190531B: Swift-XRT afterglow detection
- GRB 190531B: Fermi GBM observations
- GRB 190530A: Swift/UVOT Detection
- GRB 190531B: Fermi-LAT detection
- GRB 190530A: Fermi GBM observation
- GRB 190530A: Swift-XRT afterglow detection
- GRB 190530A: OAJ optical detection
- GRB 190530A: Fermi-LAT detection
- IceCube-190504A: Kanata optical/NIR follow-up observations
- LIGO/Virgo S190521r: Coverage and upper limits from Fermi-LAT observations
- LIGO/Virgo S190521g: No candidate counterpart in Fermi-LAT observations
- LIGO/Virgo S190521r: No counterpart candidates in INTEGRAL SPI/ACS prompt observation
- LIGO/Virgo S190519bj: Fermi-LAT search for a high-energy gamma-ray counterpart
- LIGO/Virgo S190521g: No counterpart candidates in INTEGRAL SPI/ACS & IBIS/PICsIT prompt observations
- LIGO/Virgo S190521g: INTEGRAL SPI/ACS prompt observation
- GRB 190519A: Swift-XRT refined Analysis
- LIGO/Virgo S190519bj: INTEGRAL SPI/ACS prompt observation
- GRB 190519A: Fermi GBM observation
- LIGO/Virgo S190426c: NICER X-ray Follow-Up of ZTF19aassfws
- LIGO/Virgo S190517h: INTEGRAL prompt observation
- GRB 190511A: Swift/UVOT further analysis
- LIGO/Virgo S190517h: Fermi-LAT search for a high-energy gamma-ray counterpart
- LIGO/Virgo S190517h: INTEGRAL/SPI-ACS prompt observation
- GRB 190515B: Swift-XRT refined Analysis
- GRB 190515A: Fermi-LAT detection
- LIGO/Virgo S190510g: Swift-XRT observations and results
- LIGO/Virgo S190513bm: Fermi-LAT search for a high-energy gamma-ray counterpart
- LIGO/Virgo S190513bm: INTEGRAL prompt observation
- LIGO-Virgo S190512at: AGILE GRID observations
- LIGO/Virgo S190512at: Fermi-LAT search for a high-energy gamma-ray counterpart
- GRB 190512A: Fermi GBM observation
- GRB 190511A: Swift-XRT refined Analysis
- GRB 190511A: Swift/UVOT Detection
- GRB 190511A: Fermi-LAT detection
- GRB 190511A: Fermi GBM observation
- LIGO/Virgo S190510g: Unconfirmed OT in PGC 094244
- LIGO/Virgo S190510g: MASTER possible OT in PGC094244 galaxy
- LIGO/Virgo S190510g: J-GEM optical/NIR follow-up observations
- LIGO/Virgo S190510g: Fermi-LAT search for a high-energy gamma-ray counterpart
- GRB 190501A: Swift XRT and UVOT Observations
- LIGO/Virgo S190426c: Konus-Wind observations
- LIGO/Virgo S190425z: Konus-Wind observations
- Fermi-LAT Gamma-ray Observations of IceCube-190504A
- LIGO/Virgo S190503bf: Fermi-LAT search for a high-energy gamma-ray counterpart
- Fermi-LAT Gamma-ray Observations of IceCube-190503A
- IceCube-190503A: INTEGRAL prompt observation
- LIGO/Virgo S190503bf: INTEGRAL prompt observation
- LIGO/Virgo S190425z: Insight-HXMT observation and counterpart search
- LIGO/Virgo S190412m: Further J-GEM optical/NIR observations
- LIGO/Virgo S190425z: KPED Follow-Up of ZTF transients
- LIGO/Virgo S190426c: Fermi-LAT search for a high-energy gamma-ray counterpart
- LIGO/Virgo S190425z: VISTA K-band observations of the Swift/UVOT Transient
- LIGO/Virgo S190425z : IRSF/SIRIUS NIR photometric follow-up observation of the Swift/UVOT Transient
- LIGO/Virgo S190425z: KPED Follow-Up of ZTF transients
- LIGO/Virgo S190425z: Swift/UVOT and XRT pre-images at the position of the potential Swift/UVOT counterpart
- GRB 190427A: Fermi GBM detection
- LIGO/Virgo S190426c: Swift-XRT sources
- LIGO/Virgo S190425z: Fermi-LAT search for a high-energy gamma-ray counterpart
- GRB 190427A: NOT optical observations
- LIGO/Virgo S190426c: INTEGRAL prompt observation
- LIGO/Virgo S190425z : IRSF/SIRIUS NIR photometry of ZTF19aarykkb and ZTF19aarzaod