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"32491 results found.
- GRB 230228A: Swift-BAT refined analysis
- GRB 230228A: Swift/UVOT Upper Limits
- Fermi GRB 230301B: Global MASTER-Net observations report
- GRB 230228A: Fermi GBM Observation
- GRB 230228A: OSN optical upper limit
- GRB 230228A: Swift-XRT refined Analysis
- GRB 230228A: Mondy optical upper limit
- GRB 230228A: Nanshan/NEXT optical upper limit
- GRB 230228A: Miryang Arirang Astronomical Observatory (MAAO) 0.7-m telescope optical upper limit
- Fermi GRB 230227A: Global MASTER-Net observations report
- GRB 230217A: VLT/FORS2 optical observations and candidate counterpart
- GRB 230216A Mondy Observations
- GRB 230205A: VLA radio afterglow confirmation
- GRB 230217A: Swift/UVOT Upper Limits
- GRB 230216A: Swift/UVOT Upper Limits
- GRB 230217A: Continued Gemini Observations
- GRB 230220A: Correction to GCN 33352
- GRB 230217A: Swift-XRT afterglow detection
- Fermi-LAT gamma-ray observations of IceCube-230220A
- GRB 230217A: Swift-BAT refined analysis
- Fermi GRB 230220B: Global MASTER-Net observations report
- GRB 230217A: AstroSat CZTI detection
- GRB 230217A: Gemini South optical upper limits
- GRB 230216B: CALET Gamma-Ray Burst Monitor detection
- GRB 230217A: 6 GHz VLA observations
- GRB 230217A: Gemini-South Optical Observation
- GRB 230217A: Fermi GBM observation
- IceCube-230217A: BOOTES-4/MET Optical Observations
- Fermi-LAT gamma-ray observations of IceCube-230217A
- Konus-Wind detection of GRB 230217A
- GRB 230217A: Swift-XRT observations
- GRB 230218A is not a GRB
- GRB 230217A: AGILE/MCAL detection
- GRB 230207B: CALET Gamma-Ray Burst Monitor detection
- GRB 230216B: AstroSat CZTI detection
- GRB 230216A: SVOM/C-GFT optical upper limit
- GRB 230216A: Swift-BAT refined analysis
- GRB 230216A: Swift-XRT refined Analysis
- GRB 230205A: Lowell Discovery Telescope Observations
- GRB 230204B: Lowell Discovery Telescope Observations
- Swift GRB 230216A: Global MASTER-Net observations report
- GRB 230216A: AKO Upper Limit
- GRB 230216A: Zadko observatory - Gingin optical observations
- Fermi GRB 230215A: Global MASTER-Net observations report
- GRB 230209B: AGILE detection
- GRB 230209B: Fermi GBM Observation
- IPN triangulation of GRB 230209B
- GRB 230204B: CALET Gamma-Ray Burst Monitor detection
- GRB 230204B: ATCA radio detection
- Outburst from LS V +44 17 / RX J0440.9+4431: Transient detection by GRBAlpha
- 230211A is not a GRB
- GRB 230209B: Swift/BAT-GUANO detection outside the coded FOV
- Fermi GRB 230209B: Global MASTER-Net observations report
- GRB 230205A: 6 GHz VLA observations
- GRB 230209A is not a GRB
- GRB 230205A: SUBARU HSC pre-imaging for host galaxy search
- GRB 221009A: Continued Swift Observations
- GRB 230207B: Detection by GRBAlpha
- GRB 230205A: possible host galaxy detection with the Schmidt - Asiago telescope
- GRB 230204B: MASTER early OT detection
- GRB 230207B: Swift/BAT-GUANO detection outside the coded FOV
- ZTF23aabmzlp/AT2023azs: Neil Gehrels Swift Observatory X-ray observations
- Fermi GRB 230207A: Global MASTER-Net observations report
- GRB 230204B: LCOGT Optical Upper Limits
- GRB 230204B: Swift/UVOT Upper Limits
- GRB 230205A: Swift/UVOT Upper Limits
- GRB 230204B: Fermi GBM detection
- Fermi Gamma-ray Burst Monitor triggers due to recent activity of RX J0440.9+4431 (LS V +44 17)
- GRB 230205A: LCOGT Optical Upper Limits
- GRB 230204B: Swift-XRT afterglow detection
- GRB 230204B: 3.6m DOT optical observation
- GRB 230205A: SVOM/C-GFT optical upper limit
- GRB 230205A: OHP/T193 optical observations
- GRB 230204B: VLT/X-shooter redshift
- GRB 230205A: Swift-BAT refined analysis (T90 = 2.3 s)
- GRB 230204A: Swift-BAT refined analysis
- GRB 230204B: ATLAS detection of the optical afterglow and a projected location in a nearby galaxy group
- GRB 230205A: Swift-XRT refined Analysis
- GRB 230204B: Swift ToO observations
- GRB 230204B: Detection by GRBAlpha
- IceCube-230201A: BOOTES-4/MET Optical Upper Limits
- GRB 230204B: GIT discovery of the likely optical afterglow
- GRB 230204B: AstroSat CZTI detection
- GRB 230204B: Swift/BAT-GUANO detection outside the coded FOV
- GRB 230204A: Swift/UVOT Upper Limits
- GRB 230204A: Swift-XRT refined Analysis
- GRB 230204A/Swift J1552.8-5055: LCOGT Optical Counterpart Candidate
- GRB 230201B: TURBO Optical Upper Limits
- ZTF23aabmzlp/AT2023azs: Lulin 1m LOT optical observations
- GRB 221216A: Swift-BAT refined analysis
- ZTF23aabmzlp/AT2023azs: VLA radio detection
- ZTF23aaarlti/AT2023avj: AMI-LA radio detection
- ZTF23aabmzlp/AT2023azs: AMI-LA radio upper limit
- Fermi GRB 230201B: Global MASTER-Net observations report
- Fermi-LAT gamma-ray observations of IceCube-230201A
- GRB 230126A: Detection by VZLUSAT-2
- Fermi GRB 230201A: Global MASTER-Net observations report
- GRB 221009A: radio afterglow detection with the EVN
- ZTF23aabmzlp/AT2023azs: LCOGT Optical Detection
- ZTF23aaarlti/AT2023avj: Assy continued optical observations