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.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
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"21458 results found.
- GRB 230325A: X-shooter optical afterglow and redshift
- GRB 230325A: Swift-XRT refined Analysis
- GRB 230322B: Swift-BAT refined analysis
- GRB 230325A: Enhanced Swift-XRT position
- GRB 230325A: Prompt enhanced Swift-XRT position
- GRB 230325A: Swift detection of a burst
- GRB 230320B: Fermi GBM Observation
- GRB 230322B: Swift/UVOT Detection
- GRB 230322B: Swift-XRT refined Analysis
- GRB 230322B: Enhanced Swift-XRT position
- Swift GRB 230322B: Global MASTER-Net observations report
- GRB 230322B: Swift detection of a burst with optical counterpart
- GRB 230320B: GRBAlpha detection
- GRB 230320B: Swift/BAT-GUANO detection outside the coded FOV
- Trigger 1160641: Swift detection of 4U 1630-472 (a.k.a. SWIFT J1633.8-4724A)
- IPN triangulation of GRB 230309A
- VZLUSAT-2 detection of SGR 1806-20
- GRB 230307A: Swift/UVOT detection
- GRB 230307A: soft X-ray detection with LEIA
- GRB 230307A: Swift-XRT afterglow detection
- Swift GRB230311.85: Global MASTER-Net observations report
- Swift GRB230311.83: Global MASTER-Net observations report
- Further improved IPN localization for GRB 230307A
- Swift GRB230311.81: Global MASTER-Net observations report
- GRB 230307A: SOAR/Goodman detection of the possible host galaxy
- Swift GRB230311.84: Global MASTER-Net observations report
- Swift Trigger 1159438 is also due to the Star Tracker loss of lock.
- Swift GRB230311.82: Global MASTER-Net observations report
- Triggers 1159434, 1159435 and 1159437: Swift detection of Sco X-1 due to Star Tracker loss of lock
- Trigger 1159327: Swift detection of SGR1806-20
- GRB 230307A: MAXI/GSC upper limit
- GRB 230307A: Possible optical afterglow
- GRB 230307A: ASO-S/HXI detection
- GRB 230228A: NUTTelA-TAO / BSTI Optical Limits
- GRB 230307A: optical upper limit
- GRB 230217A: ATCA rapid-response radio detection
- Swift Trigger 1159108 is not a GRB
- GRB 230307A: Swift/BAT upper limits on the early afterglow
- GRB 230307A: Swift-XRT observations
- GRB 230228A: VIRT Optical Upper Limit
- Improved IPN localization for GRB 230307A
- GRB 230307A: Tiled Swift observations
- IPN triangulation of GRB 230307A (long/very bright)
- GRB 230228A: 6 GHz VLA radio upper limit
- GRB 230228A: Swift-BAT refined analysis
- GRB 230228A: Swift/UVOT Upper Limits
- 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: Enhanced Swift-XRT position
- GRB 230228A: Nanshan/NEXT optical upper limit
- GRB 230228A: Miryang Arirang Astronomical Observatory (MAAO) 0.7-m telescope optical upper limit
- GRB 230228A: Prompt enhanced Swift-XRT position
- GRB 230228A: Swift detection of a possibly short burst
- GRB 230217A: VLT/FORS2 optical observations and candidate counterpart
- GRB 230216A Mondy Observations
- GRB 230217A: Swift/UVOT Upper Limits
- GRB 230216A: Swift/UVOT Upper Limits
- GRB 230217A: Continued Gemini Observations
- GRB 230217A: Swift-XRT afterglow detection
- GRB 230217A: Swift-BAT refined analysis
- GRB 230217A: AstroSat CZTI detection
- GRB 230217A: 6 GHz VLA observations
- GRB 230217A: Fermi GBM observation
- Konus-Wind detection of GRB 230217A
- GRB 230217A: Swift-XRT observations
- GRB 230217A: AGILE/MCAL detection
- GRB 230207B: CALET Gamma-Ray Burst Monitor detection
- GRB 230216A: SVOM/C-GFT optical upper limit
- GRB 230217A: Swift detection of a short burst
- GRB 230216A: Swift-BAT refined analysis
- GRB 230216A: Swift-XRT refined Analysis
- GRB 230205A: Lowell Discovery Telescope Observations
- Swift GRB 230216A: Global MASTER-Net observations report
- GRB 230216A: Enhanced Swift-XRT position
- GRB 230216A: AKO Upper Limit
- GRB 230216A: Zadko observatory - Gingin optical observations
- GRB 230216A: Swift detection of a burst
- GRB 230209B: AGILE detection
- GRB 230209B: Fermi GBM Observation
- IPN triangulation of GRB 230209B
- GRB 230204B: CALET Gamma-Ray Burst Monitor detection
- GRB 230209B: Swift/BAT-GUANO detection outside the coded FOV
- Swift Trigger 1153670 is probably not a GRB
- GRB 230205A: 6 GHz VLA observations
- 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 230207B: Swift/BAT-GUANO detection outside the coded FOV
- ZTF23aabmzlp/AT2023azs: Neil Gehrels Swift Observatory X-ray observations
- GRB 230204B: Swift/UVOT Upper Limits
- GRB 230205A: Swift/UVOT Upper Limits
- GRB 230204B: Fermi GBM detection
- GRB 230205A: LCOGT Optical Upper Limits
- GRB 230204B: Swift-XRT afterglow detection
- GRB 230205A: SVOM/C-GFT optical upper limit
- GRB 230205A: Swift-BAT refined analysis (T90 = 2.3 s)
- GRB 230204A: Swift-BAT refined analysis