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"14822 results found.
- GRB 260924A: Near-infrared detection with MDM/MIRAGE
- GRB 260926A: Fermi GBM Final Real-time Localization
- GRB 260924A: Second-epoch J-band upper limit from the SYSU 80 cm infrared telescope
- EP260924a: EP-FXT follow-up observation
- Konus-Wind detection of GRB 260924A
- GRB 260923A: Glowbug gamma-ray detection
- GRB 260924A: Optical follow-up observations with Kinder
- GRB 260922A: Glowbug gamma-ray detection
- GRB 260924A: Ondrejov D50 optical afterglow detection
- GRB 260924A: 2.2m CAHA spectroscopic redshift z = 3.51
- GRB 260925A: Swift detection of a burst
- GRB 260923A: Insight-HXMT/HE detection
- EP260924a: EP-WXT detection of an X-ray transient
- GRB 260924A: Swift/UVOT Detection
- GRB 260924A: NuSTAR detection of prompt emission
- GRB 260924A: Swift/UVOT Upper Limits
- Konus-Wind detection of GRB 260922A
- GRB 260922A: NuSTAR detection of prompt emission
- GRB 260921A: NuSTAR detection of prompt emission
- Konus-Wind detection of GRB 260921A (correction to GCN 45722)
- 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: detection of a bright optical afterglow by the 1.5m OSN telescope
- GRB 260922A: CALET Gamma-Ray Burst Monitor detection
- GRB 260924A: Swift detection of a burst
- GRB 260924A: Fermi GBM Final Real-time Localization
- GRB 260923A: Fermi GBM Final Real-time Localization
- EP260806a: e-MERLIN detection at 5 GHz
- GRB 260922A: Ondrejov D50 optical limit
- ATCA observations of GRB 260909A
- Konus-Wind detection of GRB 260810A
- GRB 260920A: Glowbug gamma-ray detection
- GRB 260922A: Swift detection of a burst
- GRB 260917C: AstroSat CZTI detection
- GRB 260920B/EP260920b: GECAM-B detection of a burst
- GRB 260921A: AstroSat CZTI detection
- GRB 260921B: Fermi GBM Final Localization
- EP260920b: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
- Swift GRB 260921A: MASTER OT J094129.58+025052.5 possible optical counterpart detection with host galaxy (z=1.3)
- GRB 260921A: Swift detection of a burst
- GRB 260921A: Fermi GBM Final Real-time Localization
- GRB 260920A: AstroSat CZTI detection
- EP260920b: LCO optical counterpart detection
- EP260920b: Einstein Probe detection of an X-ray transient
- 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
- EP260917b: EP-FXT non-detection and upper limit
- EP260920a: LCO optical counterpart candidate
- EP260920a: Einstein Probe detection of an X-ray transient
- GRB 260915A: VLT optical and near-infrared upper limits
- IceCube-260919A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260918A: SVOM/C-GFT optical upper limits
- Fermi GBM Sub-Threshold Detection of GRB 260918A
- Konus-Wind detection of GRB 260916B (short/hard)
- GRB 260918A: SVOM/VT optical upper limits
- GRB 260916B: Glowbug gamma-ray detection of a short burst
- GRB 260917B: Mondy optical upper limit
- IPN triangulation of GRB 260916B (short)
- EP260917b: EP-WXT detection of an X-ray transient
- IPN triangulation of GRB 260810A
- GRB 260917B: EP-FXT follow-up observation
- GRB 260915A: Swift-XRT afterglow detection
- EP260917a: Einstein Probe detection of an X-ray transient
- GRB 260918A: SVOM detection of a burst
- GRB 260917C: Fermi GBM Final Real-time Localization
- GRB 260917B: FRAM-Auger optical limits
- GRB 260916B: Fermi GBM Detection
- GRB 260916B: Fermi GBM Final Localization
- GRB 260917A: Glowbug gamma-ray detection
- GRB 260917B: WINTER J-band observations
- GRB 260917B: SVOM/VT optical observations
- GRB 260917B: LCO optical observation
- GRB 260917B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
- GRB 260917B: SVOM detection of a faint burst
- GRB 260914A: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
- GRB 260917A: Fermi GBM Final Real-time Localization
- IceCube-260916A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260909A: NOEMA detection
- GRB 260916A: MAXI/GSC detection
- GRB 260915A: J-band upper limit by SYSU 80cm infrared telescope
- GRB 260915A: SVOM/C-GFT optical upper limits
- GRB 260915A: 10.4m GTC deep optical limits
- GRB 260915A: SVOM/VT optical upper limits from VHF data
- Fermi GBM Sub-Threshold Detection of GRB 260915A
- GRB 260915A: SVOM detection of a burst
- Fermi GBM Sub-Threshold Detection of GRB 260914A
- GRB 260914A: SVOM detection of a burst
- GRB 260818A: Continued ATCA observations
- GRB 260913A: SVOM detection of a faint burst
- GRB 260909A: OSN 1.5m, CAHA 2.2m and GTC 10.4m optical upper limits
- GRB 260910B: GOTO tentative optical counterpart candidates
- GRB 260910B: Fermi GBM Final Real-time Localization
- EP260806a: VLA+ALMA radio detections
- GRB 260910A: Fermi GBM Final Real-time Localization
- EP260806a: NOEMA detection
- EP260623a: NOEMA detections
- GRB 260909A: SVOM detection of a burst