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"19572 results found.
- GRB 200716C: Enhanced Swift-XRT position
- GRB 200716C: Swift detection of a burst with an optical counterpart
- IPN triangulation of GRB 200716A
- GRB 200715A: Swift ToO observations
- GRB 200714E: Swift ToO observations
- Fermi GRB 200714D: Global MASTER-Net observations report
- GRB 200713A: Enhanced Swift-XRT position
- GRB 200713A: Swift detection of a burst
- GRB 200711A: AbAO optical upper limit
- GRB 200711A: Swift/UVOT Upper Limits
- GRB 200711A: Swift-BAT refined analysis
- GRB 200711A: Swift-XRT refined Analysis
- GRB 200711A: Swift detection of a burst
- Update of alert from the HAWC Burst Monitor HAWC-200709A
- GRB 200709B/HAWC-200907A: Swift-XRT further observations
- HAWC-200907A: No Neutrino Counterpart detected with ANTARES
- GRB 200709B: Tiled Swift observations
- Trigger 980513: Swift detection of SGR Swift J1818.0-1607
- GRB 200630A: Swift/UVOT Upper Limits
- GRB 200623A: Swift XRT further observations
- GRB 200630A: Enhanced Swift-XRT position
- GRB 200630A: Swift detection of a burst
- GRB 200625A: Fermi-LAT detection is likely a flare from PKS 1127-14
- GRB 200623A: LBT optical observations
- GRB 200625A: Swift ToO observations
- GRB 200623A: MMT observations at XRT Source #3
- GRB 200623A: Swift/UVOT Upper Limits
- IPN triangulation of GRB 200623B (short)
- GRB 200623A: OAJ deep multi-color imaging, XRT #2 is pre-detected
- GRB 200623A: TNG optical observations
- GRB 200623A: AbAO afterglow candidate within XRT #2
- GRB 200623A: Swift ToO observations
- IceCube-200620A: No significant detection in HAWC
- Fermi-LAT Gamma-ray Observations of IceCube-200620A
- GRB 200613A: R-band observations from HCT
- GRB 200613A: Further Liverpool Telescope observations
- GRB 200613A: SAO RAS optical observations
- IceCube-200530A - SN2020lls likely unrelated
- Swift/UVOT Observations of IceCube 200615A
- Swift-XRT observations of IceCube 200615A
- IceCube-200615A: No significant detection in HAWC
- GRB 200613A: Jet-break from Xinglong-2.16m optical observations
- Fermi-LAT Gamma-ray Observations of IceCube-200615A
- IceCube-200614A: No significant detection in HAWC
- Fermi-LAT Gamma-ray Observations of IceCube-200614A and detection of a new gamma-ray source, Fermi J0202.8+3132
- GRB 200613A: MITSuME Akeno optical upper limits
- IceCube-200615A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- IceCube-200614A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 200613A: Continued Xinglong-2.16m optical observations
- GRB 200613A: Swift/UVOT Detection
- GRB 200613A: Xinglong-2.16m optical observations
- GRB 200613A: Liverpool Telescope observations
- GRB 200613A: Swift-XRT afterglow detection
- GRB 200613A: Swift ToO observations
- GRB 200612A: Swift/UVOT Upper Limits
- GRB 200612A: Enhanced Swift-XRT position
- GRB 200612A: Swift detection of a burst
- GRB 200608A: Swift detection of a burst
- IPN triangulation of GRB 200605A (short)
- GRB 200529A: Swift/UVOT Upper Limits
- Fermi-LAT Gamma-ray Observations of IceCube-200530A
- GRB 200529A: MITSuME Akeno optical upper limits
- IceCube-200530A: No significant detection in HAWC
- IceCube-200530A: No ANTARES neutrino counterpart
- IceCube-200530A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 200529A: Swift-XRT refined Analysis
- GRB 200528A: Assy optical upper limit
- GRB 200529A: Enhanced Swift-XRT position
- GRB 200529A: KAIT Optical Afterglow Confirmation
- GRB 200529A: NOT optical afterglow
- GRB 200529A: Swift detection of a burst
- GRB 200528A: NOT optical upper limits
- GRB 200528A: Swift/UVOT Upper Limits
- GRB 200528A: Nanshan/NEXT optical upper limit
- GRB 200528A: Enhanced Swift-XRT position
- GRB 200528A: MITSuME Akeno optical upper limits
- GRB 200528A: Swift detection of a burst
- GRB 200524A: Assy optical observations
- GRB 200522A: Hubble Space Telescope Near-IR F160W Observations
- GRB 200524A: optical upper limits from further MITSuME Akeno observation
- GRB 200522A: Gemini North optical imaging
- GRB 200524A: Further Liverpool Telescope observations
- Fermi-LAT Gamma-ray Observations of IceCube-190523A
- GRB 200524A: KAIT Optical Observations
- GRB 200524A: MITSuME Akeno optical observation
- GRB 200524A: Swift-XRT afterglow detection
- GRB 200524A: OAJ multicolor afterglow detection
- GRB 200524: Swift/UVOT observations missed the ZTF20abbiixp position
- GRB 200524A: CAHA multicolor afterglow detection
- GRB 200524A: Correction to the GCN 27800
- GRB 200524A: 3.6m DOT observations of the afterglow candidate ZTF20abbiixp
- GRB 200524A: GROWTH-India confirmation of optical afterglow
- GRB 200524A: Swift ToO observations
- GRB 200522A: Swift/UVOT Upper Limits
- GRB 200522A: Enhanced Swift-XRT position
- GRB 200522A: Swift detection of a short burst
- GRB 200519A: Swift/UVOT Detection
- GRB 200519A: GROWTH-India optical follow-up
- GRB 200519A: Enhanced Swift-XRT position
- GRB 200519A: iTelescope optical afterglow detection