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"25891 results found.
- GRB 240225B: Swift-XRT observations
- GRB 240225B: GOTO detection of a candidate optical afterglow
- Transient EPW20240219aa: REM optical/NIR upper limits
- GRB 240222A: ATCA radio observations
- GRB 240225B: Tiled Swift observations
- Transient EPW20240219aa: Xinglong-2.16m optical upper limit
- GRB 240218A: VLA detection
- GRB 240225A: Swift/BAT-GUANO detection of a short burst
- GRB 240222A: GRBAlpha detection
- Swift-BAT triggers 1217218-1217222 are not astrophysical
- Transient EPW20240219aa: Mondy optical observations
- Insight-HXMT/HE Sub-Threshold Detection of Transient EPW20240219aa
- Swift BAT Sub-Threshold Detection of EPW20240219aa
- GRB 240222A: GECAM detection of a burst
- GRB 240222A: Swift-BAT refined analysis
- GRB 240222A: Swift-XRT refined Analysis
- Swift-BAT triggers 1216907-1216911 are not astrophysical
- GRB 240222A: Fermi GBM Observation
- GRB 240222A: Swift/UVOT Upper Limits
- Swift GRB 240222A: Global MASTER-Net observations report
- Swift Trigger 1216864 is not an astrophysical event
- GRB 240222A: REM optical and NIR early-time observations
- GRB 240222A: Swift detection of a burst
- Swift-BAT triggers 1216751 and 1216753 are not astrophysical events
- Swift-BAT triggers 1216743-1216748 are not astrophysical
- Swift GRB240221.92: Global MASTER-Net observations report
- GRB 240218A: MeerLICHT upper limits
- GRB 240215B: Fermi GBM Observation
- GRB 240218A: LBT H-band detection
- GRB 240218A: Swift-BAT refined analysis
- Konus-Wind detection of GRB 240218A
- GRB 240218A: Swift-XRT refined Analysis
- GRB 240218A: VLT/X-shooter redshift of z = 6.782
- GRB 240218A: Fermi GBM Detection
- GRB 240215A: Fermi GBM Observation
- GRB 240215B: GRBAlpha detection
- IPN triangulation of GRB 240209A
- GRB 240218A: Enhanced Swift-XRT position
- GRB 240218A: REM detection of a NIR afterglow candidate
- GRB 240218A : r-band upper limit from Observatoire de Haute-Provence
- GRB240218A: VLT/X-shooter upper limits
- GRB 240218A: Swift detection of a burst
- Swift GRB240218.08: Global MASTER-Net observations report
- GRB 240215B: Swift/BAT-GUANO detection of a burst outside the coded FOV
- Swift Triggers 12156887-1215690 are not astrophysical events.
- GRB 240215A: Tiled Swift observations
- GRB 240215A: Swift/BAT-GUANO localization of a burst
- GRB240209A: OHP/T193 detection of the GOTO afterglow candidate AT2024cew / GOTO24pw
- GRB 240209A: Wendelstein Optical Observations
- GRB 240128A: Further Swift-XRT observations
- GRB 240214A: Tiled Swift observations
- GRB 240214A/1H 0451-560: MAXI/GSC detection
- Konus-Wind detection of GRB 240204A
- IPN triangulation of GRB 240205A (short)
- GRB 240205B: PRIME near infrared detection
- Swift Trigger 1213872 is not an astrophysical event
- GRB240204A: Swift/UVOT Upper Limits
- GRB 240205B: AstroSat CZTI detection
- GRB 240205B: Swift-BAT refined analysis
- Konus-Wind detection of GRB 240205B (long / very soft)
- GRB 240205B: VLT/X-shooter redshift
- GRB 240205B: CALET Gamma-Ray Burst Monitor detection
- GRB 240205B: BOOTES-6 optical afterglow follow-up
- GRB 240205B: ATCA detection of radio counterpart
- GRB 240205B: REM detection of the optical/NIR afterglow
- GRB 240205B: Fermi GBM Observation
- GRB 240204A: AstroSat CZTI detection
- GRB 240204A: Mondy optical afterglow observations
- GRB 240204A : OHP/T193/T120 optical afterglow fading detection
- GRB 240205B: GECAM detection of a long burst
- GRB 240204A: Swift-BAT refined analysis
- GRB 240205B: Skynet Optical Afterglow Observations
- GRB 240205B: BOOTES-7 optical afterglow follow-up
- GRB 240205B: MASTER OT J232550.14-550704.6 counterpart detection
- GRB 240205B: Swift detection of a burst
- Swift GRB240205.93: Global MASTER-Net observations report
- GRB 240204A: Fermi GBM Observation
- GRB 240204a: Liverpool Telescope optical afterglow detection
- GRB 240204A: Osservatorio Astronomico Nastro Verde upper limit
- GRB 240204A: optical afterglow detection with LCOGT 1m telescopes at Sutherland and Teide Observatories
- GRB 240204A: Montarrenti Observatory optical observations
- GRB 240204A: Enhanced Swift-XRT position
- GRB 240204A: Mondy optical afterglow candidate
- GRB 240204A: Swift detection of a burst
- Swift Trigger 1212791 is not an astrophysical event.
- Swift-BAT triggers 1212787, 1212789 are not astrophysical.
- IPN triangulation of GRB 240124B
- GRB 240129A: Fermi GBM Observation
- GRB 240129A: Swift/BAT-GUANO detection of a burst outside the coded FOV
- IPN triangulation of GRB 240125A (short)
- GRB 240128A: Swift-XRT observations
- GRB 240128A: Tiled Swift observations
- GRB 240122A: ATCA detection of radio counterpart
- Swift Trigger 1211211 and 1211212 are not astrophysical
- GRB 240123C: AstroSat CZTI detection
- GRB240122A: PRIME near infrared detection
- GRB 240123B: Fermi GBM Observation
- GRB 240123A: Glowbug gamma-ray detection
- GRB 240123B: Swift/BAT-GUANO detection of a long burst
- GRB 240123A: GRBAlpha detection