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"19875 results found.
- GRB 240825A: AKO Optical Afterglow Detection
- GRB 240825A: Skynet Optical Afterglow observations
- GRB 240825A: Nanshan/HMT optical afterglow observations
- GRB 240825A: Swift detection of a burst with a bright optical counterpart
- GRB 240824A: Swift-BAT refined analysis
- GRB 240824A: SVOM/C-GFT optical upper limit
- GRB 240824B: Swift-XRT afterglow detection
- GRB 240824A: Swift-XRT observations
- GRB 240824B: Swift/BAT arcminute localization of a burst
- GRB 240824B: Swift ToO observations
- GRB 240824A: Swift/UVOT Upper Limits
- GRB 240821A: Swift/UVOT observations of the XRT sources.
- GRB240824A: GRANDMA/TAROT-TCA Upper Limit
- SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
- GRB 240824A: KAIT optical upper limit
- GRB 240824A: Skynet Optical Afterglow Discovery
- GRB 240824A: Swift detection of a burst
- Swift GRB240824.04: Global MASTER-Net observations report
- SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
- GRB 240821A: Colibri Optical Upper Limit
- GRB 240821A: Swift-XRT observations
- GRB 240821A: REM optical/NIR upper limits
- GRB 240821A: JinShan optical upper limits
- GRB 240809A: Mondy and AbAO Optical Observations
- GRB 240821A: SVOM/VT follow-up and optical upper limit
- GRB 240821A: GMG Optical Upper Limit
- GECAM-B observation of a short burst from SGR 1E 1841-045 / Kes 73
- GRB 240821A: Swift ToO observations
- Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
- Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
- GRB 240819A: Swift-XRT observations
- GRB 240819A: JinShan optical upper limits on one Swift/XRT source
- GRB 240819A: KAIT optical upper limit
- Trigger 1249653: Swift detection of SGR 1E 1841-045 / Kes 73
- GRB 240819A : an X-ray transient detected by SVOM/ECLAIRs
- GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
- GRB 240819A: Swift ToO observations
- GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
- GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
- EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
- Konus-Wind detection of GRB 240811A
- GRB 240811A: Swift-BAT refined analysis
- GRB 240809A: Swift-BAT refined analysis
- GRB 240811A: Bassano Bresciano Observatory upper limit
- GRB 240811A: Swift-XRT refined Analysis
- GRB 240811A: Swift/UVOT Upper Limits
- GRB 240811A: LCOGT Optical Upper Limit
- GRB 240811A: Enhanced Swift-XRT position
- Konus-Wind detection of GRB 240809A
- Swift GRB 240811A: Global MASTER-Net observations report
- GRB 240811A: Swift detection of a burst
- GRB 240809A: Bassano Bresciano Observatory optical observations
- GRB 240809A: KAIT optical observations
- GRB 240809A: GIT afterglow observations
- GRB 240809A: Swift/UVOT Detection
- GRB 240809A: Swift-XRT refined Analysis
- IPN triangulation of GRB 240807A / EP 240807a
- Swift GRB 240809A: Global MASTER-Net observations report
- GRB 240809A: JinShan optical observations
- GRB 240809A: Enhanced Swift-XRT position
- GRB 240809A: Skynet & Photon Ranch Optical Afterglow Observations
- GRB 240809A: SVOM/GRM observation
- GRB 240809A: Swift detection of a burst with a bright optical counterpart
- GRB 240805A: ATCA Radio Upper Limits
- GRB 240805B: GIT optical upper limit
- GRB 240805B: Swift-BAT refined analysis
- GRB 240805A: Swift-BAT refined analysis
- Konus-Wind detection of GRB 240805A
- GRB 240805B Bassano Bresciano Observatory upper limit
- GRB240805A: Fermi GBM Observation
- GRB 240805B: JinShan optical afterglow detection
- GRB 240805B: AbAO, CrAO, and Terskol optical upper limits
- GRB 240805B: Swift-XRT refined Analysis
- GRB 240805B: Swift/UVOT Upper Limits
- GRB 240805A: Swift/UVOT Upper Limits
- GRB 240805A: SVOM/GRM observation
- GRB 240805B: Enhanced Swift-XRT position
- GRB 240805B: LCOGT Optical Upper Limits
- Swift GRB 240805B: Global MASTER-Net observations report
- GRB 240805B: JinShan optical upper limits
- Swift GRB 240805A: Global MASTER-Net observations report
- GRB 240805A: Swift-XRT refined Analysis
- GRB 240805B: Swift detection of a burst
- GRB 240805A: Fermi-LAT detection
- GRB 240805A: INTEGRAL spectral analysis
- GRB 240805A: A long GRB detected by INTEGRAL
- GRB 240805A: Swift detection of a burst
- GRB 240730A: Swift-BAT refined analysis
- GRB240730A: BOOTES-5/JGT early optical upper limit
- Swift GRB 240730A: Global MASTER-Net observations report
- GRB 240730A: Swift-XRT refined Analysis
- GRB 240715A: Swift-XRT afterglow detection
- GRB 240730A: KAIT Optical Upper Limit
- GRB 240730A: Swift/UVOT Upper Limits
- GRB 240730A: Enhanced Swift-XRT position
- GRB 240730A: Swift detection of a burst
- GRB 240727A: Swift-BAT refined analysis
- LIGO/Virgo/KAGRA S240615dg: GRAWITA wide-field optical observations
- GRB 240727A: observations of optical counterpart.
- GRB 240727B: Swift-XRT observations