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"23572 results found.
- GRB 260909A: KAIT optical upper limit
- GRB 260903A: Swift-XRT observations
- EP260806a: VLA+ALMA radio detections
- GRB 260909A: OHP/T193 z-band upper limit
- EP Alert 260909.53: Global MASTER-Net observations report
- GRB 260909A: EP-FXT follow-up observation
- EP260806a: NOEMA detection
- EP260623a: NOEMA detections
- The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
- Fermi trigger No 810554827: Global MASTER-Net observations report
- EP Alert 260908.60: Global MASTER-Net observations report
- GRB 260907A: Glowbug gamma-ray detection of a likely short burst
- Fermi GRB 260907B: Global MASTER-Net observations report
- Fermi GRB 260907A: Global MASTER-Net observations report
- EP260903a: EP-FXT follow-up observation
- EP Alert 260905.11: Global MASTER-Net observations report
- GRB 260903A: J-band upper limit with WINTER
- EP Alert 260903.47: Global MASTER-Net observations report
- GRB 260903A: SVOM/ECLAIRs refined analysis
- GRB 260903A: SAO RAS optical observations
- EP260903a: EP-WXT detection of a fast X-ray transient
- EP Alert 260903.62: Global MASTER-Net observations report
- GRB 260903A: EP-FXT follow-up observation
- NuSTAR Transient 260828: SOAR Optical Upper Limits
- SVOM GRB260903A: Global MASTER-Net observations report
- GRB 260903A: LCO optical observations
- GRB 260903A: SVOM detection of a soft faint burst
- Konus-Wind detection of GRB 260829A
- EP260901a: Global MASTER-Net observations report
- NuSTAR Transient 260828: LCO Optical Upper Limits
- GRB 260829A: AstroSat CZTI detection
- EP260830a: Global MASTER-Net observations report
- IPN triangulation of GRB 260829A
- GRB 260827A: Glowbug gamma-ray detection
- EP260727a: ATCA 10 GHz detection
- GRB 260825A: AstroSat CZTI detection
- GRB 260818B: Further EP-FXT observation
- GRB 260818B: TNG NIR observations
- MAXI GRB260827.40: Global MASTER-Net observations report
- GRB 260818B: 6 GHz VLA observations
- GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
- EP260822a: Global MASTER-Net observations report
- EP Alert 260820.31: Global MASTER-Net observations report
- GRB 260809A: SVOM/ECLAIRs refined analysis
- IceCube Alert 260825A: Global MASTER-Net observations report
- GRB 260822A: PRIME near-infrared upper limits from multiple epochs
- GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
- GRB 260822A: Retraction of GOTO optical counterpart detection GCN 45431
- GRB 260822A: GOTO optical counterpart detection
- GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
- GRB 260822A: GOTO optical upper limit
- GRB 260818B: VLA radio observations
- IceCube Alert 260821A: Global MASTER-Net observations report
- The EP-WXT trigger 01709286204 is likely a flaring star
- GRB 260818B: SVOM/GRM observation
- GRB 260818A: J-band observations with WINTER
- GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- EP260806a: SAO RAS multicolor optical observations
- EP260812a: AbAO optical upper limit
- GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- EP260806a: NUTTELA-TAO optical observations
- The EP-WXT trigger 01709281429 is likely a flaring star
- EP260812a: AZT-22 optical upper limit
- EP260812b: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.034
- EP260812b: Optical upper limit with Kinder
- GRB 260808B: GTC/OSIRIS+ spectroscopic redshift z = 1.295
- EP260812b: GOTO detection of the optical counterpart
- GRB 260810A: Glowbug gamma-ray detection
- GRB 260808B: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical rebrightening
- GRB 260809A: SAO RAS optical observations
- GRB 260808B: SAO RAS optical observations
- GRB 260317A: SVOM/ECLAIRs detection through offline targeted search and its possible association to magnetar 1E 1841-04.5
- GRB 260806A: CALET Gamma-Ray Burst Monitor detection
- GRB 260807A: SVOM/ECLAIRs refined analysis
- EP260806a: MAO/AZT-22 optical observations
- GRB260808B: MAO/AZT-22 optical observations
- GRB 250607A: SVOM/ECLAIRs detection through offline targeted search
- GRB 260809A: J-band upper limit with WINTER
- GRB 260806A: Glowbug gamma-ray detection
- GRB 260808A: CALET Gamma-Ray Burst Monitor detection
- GRB 260805C: CALET Gamma-Ray Burst Monitor detection
- GRB 260804A: CALET Gamma-Ray Burst Monitor detection
- GRB 260809A: SVOM/COLIBRÍ (FM-GFT) optical observation
- GRB 260808B: SVOM/COLIBRÍ (FM-GFT) optical observation
- GRB260809A: MAO/AZT-22 optical observations
- EP260809a: J-band upper limit with WINTER
- GRB 260808B: J-band upper limit with WINTER
- GRB 260808B: SVOM/ECLAIRs refined analysis
- GRB 260809A: SVOM detection of a faint burst
- GRB 260808B: LCO optical observations
- EP260809a: COLIBRÍ optical observations
- GRB 260808B: SVOM/VT optical afterglow confirmation
- GRB 260808B: SVOM/VT optical candidate from VHF data ( localization correction for GCN 45317 )
- GRB 260808B: SVOM/VT optical candidate from VHF data
- Fermi GRB 260808A: Global MASTER-Net observations report
- IceCube Alert 260807A: Global MASTER-Net observations report
- IceCube-260805A: One candidate from the Zwicky Transient Facility
- GRB 260807A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- EP260806a: COLIBRÍ optical observations
- EP260806a: OSIRIS+/GTC redshift z=0.089