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"12089 results found.
- Fermi GRB 260926A: Global MASTER-Net observations report
- GRB 260926A: Fermi GBM Final Real-time Localization
- GRB 260924A: COLIBRÍ optical observations
- GRB 260925A: J-band upper limit by SYSU 80cm infrared telescope
- GRB 260925A: Swift-XRT refined Analysis
- Swift Trigger 1513439 is probably not a GRB
- Konus-Wind detection of GRB 260924A
- GRB 260924A: Optical follow-up observations with Kinder
- GRB 260925A: COLIBRÍ optical upper limits
- EP260924a: J-band upper limit with WINTER
- GRB 260925A: Swift detection of a burst
- GRB 260924A: Swift-XRT refined Analysis
- Konus-Wind detection of GRB 260922A
- Konus-Wind detection of GRB 260921A (possible merger-origin)
- GRB 260924A: Fermi-LAT detection of a bright burst
- GRB 260924A: AstroSat CZTI detection
- GRB 260924A: Swift detection of a burst
- Fermi GRB 260923A: Global MASTER-Net observations report
- Fermi-LAT Gamma-ray Observations of IceCube-260919A
- Fermi-LAT Gamma-ray Observations of IceCube-260916A
- EP260920a: VLT/HAWK-I near-infrared counterpart confirmation
- GRB 260922A: Swift-XRT refined Analysis
- Fermi-LAT Gamma-ray Observations of IceCube-260805A
- Konus-Wind detection of GRB 260810A
- GRB 260920A: Glowbug gamma-ray detection
- GRB 260922A: Swift detection of a burst
- GRB 260921A: AstroSat CZTI detection
- EP260920b: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
- EP Alert 260921.58: Global MASTER-Net observations report
- EP260920a: VLT/HAWK-I near-infrared candidate
- Swift GRB 260921A: Global MASTER-Net observations report
- GRB 260920A: AstroSat CZTI detection
- EP260920b: refined analysis of the EP-WXT and EP-FXT observations
- EP Alert 260921.01: Global MASTER-Net observations report
- EP260920b: Einstein Probe detection of an X-ray transient
- IceCube-260919A: Upper limits from a search for additional neutrino events in IceCube
- EP Alert 260920.66: Global MASTER-Net observations report
- EP-WXT detected a brightening of HMXB LS V +44 17
- EP260920a: NOT early time optical upper limits
- EP260920a: NOT optical upper limits
- GRB 260920A: Fermi GBM Final Real-time Localization
- EP260917a: Global MASTER-Net observations report
- EP260920a: COLIBRÍ optical upper limits
- IceCube Alert 260919A: Global MASTER-Net observations report
- EP260920a: Einstein Probe detection of an X-ray transient
- Konus-Wind detection of GRB 260916B (short/hard)
- GRB 260918A: EP-FXT follow-up observation
- EP Alert 260917.32: Global MASTER-Net observations report
- Fermi trigger No 811304653: Global MASTER-Net observations report
- GRB 260914A: SVOM/ECLAIRs refined analysis
- GRB 260916A: MAXI/GSC detection
- MAXI GRB260916.37: Global MASTER-Net observations report
- GRB 260915A: J-band upper limit by SYSU 80cm infrared telescope
- GRB 260915A: 10.4m GTC deep optical limits
- EP Alert 260914.53: Global MASTER-Net observations report
- SVOM GRB260914.47: Global MASTER-Net observations report
- GRB 260914A: SVOM detection of a burst
- GRB 260818A: Continued ATCA observations
- GRB 260909A: OHP/T193 z-band upper limit
- GRB 260909A: VLT optical and near-infrared upper limits
- EP Alert 260909.53: Global MASTER-Net observations report
- GRB 260909A: SVOM/GRM observation
- The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
- The EP-WXT trigger 01709305715 is likely a flaring star
- EP260903a: EP-FXT follow-up observation
- GRB 260903A: SVOM/ECLAIRs refined analysis
- EP260903a: EP-WXT detection of a fast X-ray transient
- EP Alert 260903.62: Global MASTER-Net observations report
- SVOM GRB260903A: Global MASTER-Net observations report
- GRB 260903A: SVOM detection of a soft faint burst
- Konus-Wind detection of GRB 260829A
- GRB 260818A: ATCA detection of a candidate radio counterpart
- EP260901a: Global MASTER-Net observations report
- GRB 260829A: AstroSat CZTI detection
- EP260830a: EP-WXT detection of a fast X-ray transient
- Fermi-LAT Gamma-ray Observations of IceCube-260827A
- Fermi-LAT Gamma-ray Observations of IceCube-260825A
- The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
- EP260822a: Global MASTER-Net observations report
- EP Alert 260820.31: Global MASTER-Net observations report
- IceCube Alert 260825A: Global MASTER-Net observations report
- GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
- GRB 260822A: LCO optical upper limits
- GRB260822B: Fermi GBM Final Localization
- Fermi-LAT Gamma-ray Observations of IceCube-260821A
- Fermi-LAT Gamma-ray Observations of IceCube-260807A
- IceCube-260821A: Upper limits from a search for additional neutrino events in IceCube
- GRB 260818B: VLA radio observations
- EP detected a brightening of LMXB 1ES 1735-26.9
- GRB260820A: Fermi GBM Final Real-Time Localization
- GRB 260818B: SVOM/ECLAIRs refined analysis
- EP260806a: SAO RAS multicolor optical observations
- EP260806a: SVOM/ECLAIRs detection through targeted search
- EP260812b: Optical upper limit with Kinder
- EP260812a: NOT and Liverpool Telescope upper limits:
- EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
- EP260812b: Einstein Probe detection of an X-ray transient
- EP trigger #01709278129 (EP260812b?): NOT optical counterpart
- GRB 260810A: AstroSat CZTI detection of a long burst
- EP260812a: Einstein Probe detection of an X-ray transient