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"25898 results found.
- GRB 230409B: Swift-BAT refined analysis
- Swift GRB 230409B: Global MASTER-Net observations report
- GRB 230409B: Swift/UVOT Detection
- GRB 230409B: Enhanced Swift-XRT position
- GRB 230409B: Swift detection of a burst
- GRB 230405B: VZLUSAT-2 detection
- Konus-Wind detection of GRB 230405B
- GRB 230405B: AGILE detection
- GRB 230405B: Swift-XRT refined Analysis
- GRB 230405B: Fermi GBM Observation
- GRB 230405B: MeerLICHT upper limits
- GRB 230307A: JWST NIRSpec observations, possible higher redshift
- GRB 230405B: Swift/UVOT Upper Limits
- GRB 230405B: AstroSat CZTI detection
- GRB 230405B: Enhanced Swift-XRT position
- Swift GRB 230405B: Global MASTER-Net observations report
- GRB 230405B: Prompt enhanced Swift-XRT position
- GRB 230405B: Swift detection of a burst
- GRB 230307A: JWST observations consistent with the presence of a kilonova
- GRB 230328B: Multa observatory optical afterglow observation
- GRB 230307A: Chandra late-time detection of the X-ray afterglow
- GRB 230228A: detection by GTC of the potential host galaxy
- GRB 230328B: Swift/UVOT Detection
- GRB 230328B : GRANDMA/Kilonova-Catcher optical detection
- GRB 230328B: CAHA 2.2m/CAFOS detection
- GRB 230328B: 3.6m DOT multiband optical observation
- Konus-Wind detection of GRB 230328B
- GRB 230328B: GRBAlpha detection
- GRB 230328B: Swift-BAT refined analysis
- GRB 230328B: Nanshan/NEXT 2nd optical observation
- GRB 230328B NUTTelA-TAO / BSTI Early Measurements
- GRB 230328B: Liverpool Telescope afterglow detection
- GRB 230328B: GIT optical follow-up
- GRB 230328B: OASDG optical observations
- GRB 230328B: Nanshan/NEXT optical upper limit
- GRB 230328B: Swift-XRT refined Analysis
- GRB 230328B: AstroSat CZTI detection
- GRB 230328B: Fermi GBM observation
- GRB 230328B: Mondy, AbAO and Kitab optical observations
- GRB 230328B: Enhanced Swift-XRT position
- GRB 230328B: Mondy optical afterglow confirmation
- GRB 230328B: Swift detection of a burst with an optical afterglow
- GRB 230325A: Swift-BAT refined analysis
- GRB 230325A: Swift/UVOT Upper Limits
- 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)
- GRB 230307A: Continued Gemini-South observations confirm rapid optical fading
- IPN triangulation of GRB 230309A
- VZLUSAT-2 detection of SGR 1806-20
- GRB 230307A: INTEGRAL upper limit on Hard X-ray afterglow
- 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
- TESS Detection of the Optical Afterglow of GRB230307A
- Trigger 1159327: Swift detection of SGR1806-20
- GRB 230307A: GECKO optical observations and detections of the afterglow
- GRB 230307A: MAXI/GSC upper limit
- GRB 230307A: Gemini-South Confirmation of the Optical Afterglow
- GRB 230307A: ATLAS information on the ULTRACAM optical afterglow candidate
- GRB 230307A: Erratum of the GCN 33441
- GRB 230204B: MASTER detection of an object near NTT Optical Afterglow Candidate
- 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