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"11752 results found.
- EP240930a: Liverpool Telescope observations
- GRB 241002A: Swift-XRT refined Analysis
- GRB 241002B: GOTO optical counterpart candidate
- GRB 241002C : Detection of a long soft transient by SVOM/ECLAIRs
- Fermi GRB 241002B: Global MASTER-Net observations report
- GRB 241002A: Swift detection of a burst
- GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
- Fermi-LAT Gamma-ray Observations of IceCube-240929A
- EP240930a: GOTO optical upper limits
- EP EP240930a: Global MASTER-Net observations report
- SVOM/GRM detection of a burst from SGR Swift J1818.0-1607
- GRB 240929A : Leavitt Observatory optical upper limit
- Fermi GRB 240930B: Global MASTER-Net observations report
- Fermi GRB 240930A: Global MASTER-Net observations report
- GRB 240929A long GRB detected by INTEGRAL
- Fermi GRB 240929A: Global MASTER-Net observations report
- Konus-Wind detection of GRB 240912A
- LIGO/Virgo/KAGRA S240921cw: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240920dw: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240919bn: Upper limits from Swift/BAT-GUANO
- EP trigger ID 01709061302: the X-ray transient is likely a stellar flare event
- Konus-Wind detection of GRB 240905B
- LIGO/Virgo/KAGRA S240925n: NED Galaxies in the Localization Volume
- EP240918b and EP240918c: EP-FXT follow-up observations
- Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
- GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
- LIGO/Virgo/KAGRA S240925n: Identification of a GW compact binary merger candidate
- Konus-Wind detection of GRB 240918B
- IPN triangulation of GRB 240918B
- EP trigger ID 01709059262: the X-ray transient is likely a stellar flare event
- LIGO/Virgo/KAGRA S240923ct: Identification of a GW compact binary merger candidate
- LIGO/Virgo S240919bn: GOTO optical upper limits
- LIGO/Virgo S240919bn: Swift XRT observations, 10 X-ray sources
- GRB 240918B: AstroSat CZTI detection
- LIGO/Virgo/KAGRA S240921cw: Identification of a GW compact binary merger candidate
- EP240919a: EP-FXT follow-up observation update
- EP240919a / GRB 240919A: Mondy optical upper limit
- EP240919a: Optical upper limit with Kinder observations
- GRB 240919A / EP240919a: SVOM/GRM observation
- EP240919a: INTEGRAL SPI-ACS confirmation of reported high-energy counterpart
- EP240919a: INTEGRAL SPI-ACS confirmation of reported high-energy counterpart
- LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate
- EP EP240919a: Global MASTER-Net observations report
- EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
- EP240919a: NOT and Gemini optical observations
- LIGO/Virgo/KAGRA S240920bz: Identification of a GW compact binary merger candidate
- EP240919a: EP-WXT detection of a fast X-ray transient
- GRB 240918B: Fermi GBM Detection
- EP240918a: EP observation update
- LIGO/Virgo/KAGRA S240919bn: Identification of a GW compact binary merger candidate
- Fermi GRB 240918A: Global MASTER-Net observations report
- GRB 240918A: Fermi GBM Final Real-time Localization
- EP EP240918a: Global MASTER-Net observations report
- EP240918a: YAHPT Optical Upper Limit
- EP240918a: Optical upper limits with Kinder observations
- EP240918a: an X-ray transient detected by Einstein Probe
- GRB 240916A: NOT optical observation
- LIGO/Virgo/KAGRA S240915b: NED Galaxies in the Localization Volume
- LIGO/Virgo S240915b: Swift XRT observations, 8 X-ray sources
- EP EP240913a: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240915b: Coverage and upper limits from MAXI/GSC observations
- Fermi Gamma-ray Burst Monitor trigger 748124309/240915846 is not a GRB
- GRB 240914B: AstroSat CZTI detection
- EP240913A / GRB 240913C: AstroSat CZTI detection
- EP240913a: Swift/XRT detection of an X-ray source within the EP/WXT error circle
- EP240913a: EP-WXT detection of a fast X-ray transient
- GRB 240913B: Fermi GBM Final Real-time Localization
- GRB 240912A: Swift-XRT refined Analysis
- GRB 240912A: NOT optical spectroscopy
- GRB 240912A: Swift detection of a burst with an optical counterpart
- GRB 240911A : a likely weak GRB detected by SVOM/ECLAIRs
- GRB 240825A: 7DT Optical Upper Limit
- LIGO/Virgo/KAGRA S240910ci: NED Galaxies in the Localization Volume
- LIGO/Virgo/KAGRA S240910ci: Coverage and upper limits from MAXI/GSC observations
- EP240908a: Updates on the WXT detection result around the trigger time
- Fermi GRB 240910A: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240908bs: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240907cg: Upper limits from Swift/BAT-GUANO
- GRB 240905E: GIT optical upper limit
- GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
- GRB 240905B: Fermi-LAT detection
- GRB 240905E: SVOM/C-GFT optical upper limit
- GRB 240902B: AstroSat CZTI detection of a long burst
- GRB 240905E: Swift-XRT refined Analysis
- GRB 240902A: AstroSat CZTI detection of a long burst
- GRB 240905D: AstroSat CZTI detection
- GRB 240905B: AstroSat CZTI detection and localization
- LIGO/Virgo/KAGRA S240825ar: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240807h: Upper limits from Swift/BAT-GUANO
- GRB 240825A: MeerLICHT afterglow detection
- Fermi trigger No 746923430: Global MASTER-Net observations report
- GRB 240828B: Mephisto optical upper limit
- LIGO/Virgo/KAGRA S240830gn: Coverage and upper limits from MAXI/GSC observations
- GRB 240825A: MeerKAT detection
- GRB 240828B: J-band upper limit from WINTER
- GRB 240828B: GWAC-F50A optical upper limit
- GRB 240828B: SAO RAS optical upper limit
- Fermi trigger No 746587425: Global MASTER-Net observations report
- GRB 240828A: Swift-XRT afterglow detection
- GRB 240828A: Fermi-LAT detection