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"19549 results found.
- GRB 191029A: Swift-XRT observations
- IPN triangulation of GRB 191027A
- Swift Trigger 931484 is not a GRB
- Swift Trigger 931384: possible GRB 191025A
- GRB 191024A: Swift-BAT refined analysis
- GRB 191024A: Swift/UVOT Upper Limits
- GRB 191024A: VLT/X-shooter optical observations
- GRB 191024A: GROND early upper limits
- GRB 191024A: Enhanced Swift-XRT position
- GRB 191024A: Swift detection of a burst
- GRB 191019A: Nanshan-0.6m optical observations
- GRB 191019A: Swift/UVOT Detection
- HAWC-191019A: No Neutrino Counterpart detected with ANTARES
- GRB 191019A: Enhanced Swift-XRT position
- GRB 191019A: GROND observations
- GRB 191019A: NOT optical observations
- Alert from the HAWC Burst Monitor HAWC-191019A
- GRB 191019A: TSHAO optical observations, probable afterglow and host galaxy
- GRB 191019A: Swift-XRT observations
- GRB 191017B: Swift-BAT refined analysis
- GRB 191017B: Swift/UVOT Upper Limits
- GRB 191016A: REM optical observations
- GRB 191016A: Swift-XRT afterglow detection
- GRB 191016A: Swift/UVOT Detection
- GRB 191017B: Enhanced Swift-XRT position
- GRB 191017B: Swift detection of a burst
- GRB 191016A: AZT-20 (Assy observatory) optical photometry
- GRB 191016A: early time BOOTES Network and follow-up 1.5m OSN optical observations
- GRB 191016A: RATIR Optical and NIR Observations
- GRB 191016A: COATLI Optical Observations and Detection of the Afterglow
- GRB 191016A: Swift detection of a burst
- GRB 191011A: Swift-BAT refined analysis
- GRB 191011A: Swift/UVOT Detection
- GRB 191011A: RATIR Optical and NIR Observations
- GRB 191011A: Enhanced Swift-XRT position
- GRB 191011A: correction of reported magnitudes
- GRB 191011A: GROND Detection of the Optical/NIR afterglow
- GRB 191011A: VLT X-shooter redshift from RRM Observations
- GRB 191011A: Swift detection of a burst with an optical counterpart
- LIGO/Virgo S190930t: Continued Swift observations of AT2019sbk
- TESS Detection of the Optical Emission from the Possible Untriggered GRB Associated with ZTF19abvizsw
- GRB 191008A: Fermi GBM Final Real-time Localization
- GRB 191004B: Swift/UVOT Detection
- Fermi/GBM observation of a bright burst from magnetar SGR 1935+2154
- GRB 191004A: Swift/UVOT Detection
- LIGO/Virgo S190930s: no counterpart candidate in the SVOM/GWAC observations
- LIGO/Virgo S190930t: Swift XRT observations, no secure afterglow found
- LIGO/Virgo S190930t: Swift J221951-484240 optical photometry of Chilescope observatory
- LIGO/Virgo S190930t: SALT optical spectroscopy of Swift J221951-484240
- GRB 191004B: GROND Detection of the Optical/NIR Afterglow
- GRB 191004A: GROND Upper limits
- GRB 191004B: COATLI Optical Observations
- GRB 191004B: VLT/X-shooter redshift
- GRB 191004B: NOT optical photometry
- GRB 191004A: NOT optical upper limits
- GRB 191004B: Enhanced Swift-XRT position
- GRB 191004A: Enhanced Swift-XRT position
- GRB 191004B: Swift detection of a burst with an optical counterpart
- GRB 191004A: Swift detection of a burst with an optical detection
- GRB 191001A: Swift-XRT observations
- GRB 191001B: Optical Upper Limits with LCO
- LIGO/Virgo S190930t: Continued Swift/UVOT observations of Swift J221951-484240
- GRB 190926A: Upper limit from CAHA 2.2m observation
- IceCube-191001A: HAWC follow-up
- Fermi-LAT Gamma-ray Observations of IceCube-191001A
- IPN triangulation of GRB 191001A
- LIGO/Virgo S190930t: No neutrino candidates at Pierre Auger Observatory
- GRB 191001A: Swift ToO observations
- LIGO/Virgo S190930t: Candidates from ATLAS observations and constraints on AT2019rpr and AT2019rpn
- GRB 191001A: RATIR Optical and NIR Observations
- LIGO/Virgo S190930s: no counterpart candidates in SAGUARO/CSS observations
- IceCube-191001A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 191001A: DDOTI Optical Counterpart Candidate
- LIGO/Virgo S190923y: optical spectrum of MASTER detected transient
- LIGO/Virgo S190930t: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190930s: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190930t: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S190930s: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S190930t: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S190930t: No counterpart candidates in HAWC observations
- LIGO/Virgo S190930t : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S190930s : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S190930t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S190930s: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 190926A: AbAO upper optical limit
- GRB 190926A: Upper Limit from OSN T150 Observation
- GRB 190926A: Swift/UVOT Upper Limits
- GRB 190926A: Enhanced Swift-XRT position
- GRB 190926A: Swift detection of a burst
- LIGO/Virgo S190923y: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S190924h: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190924h: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S190923y: No neutrino candidates at Pierre Auger Observatory
- Fermi-LAT Gamma-ray Observations of IceCube-190922B
- LIGO/Virgo S190924h: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- LIGO/Virgo S190924h : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S190923y: No counterpart candidates in Fermi-LAT observations
- Fermi-LAT Gamma-ray Observations of IceCube-190922A
- IceCube-190922B - HAWC follow-up
- LIGO/Virgo S190923y: INTEGRAL IBIS coded-masked imaging observations of part of the localization area and further all-sky upper limits