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"19600 results found.
- GRB 231210B: REM optical/NIR upper limits
- LIGO/Virgo/KAGRA S231206cc: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S231206ca: Upper limits from Swift/BAT-GUANO
- GRB 231210B: MeerLICHT afterglow observations
- GRB 231210B: Swift-BAT refined analysis
- GRB 231210B: Swift-XRT refined Analysis
- GRB 231210B: Enhanced Swift-XRT position
- GRB 231210B: VLT/X-shooter redshift
- GRB 231210B: detection of the optical counterpart with the LCOGT 40cm telescope at Sutherland Observatory
- GRB 231210B: Swift detection of a burst with optical counterpart
- Swift GRB231210.90: Global MASTER-Net OT detection
- Swift GRB231210.90: Global MASTER-Net observations report
- IPN triangulation of GRB 231129C
- GRB231205B: Swift/UVOT Upper Limits
- GRB 231205B: Swift-BAT refined analysis
- GRB 231205B: 1.3m DFOT Optical upper limit
- GRB 231205B: AGILE detection
- GRB 231205B: Ondrejov D50 optical upper limit
- GRB 231205B: Swift-XRT refined Analysis
- GRB 231205B: REM optical/NIR upper limits
- GRB 231129C: ASIM MXGS observation and localization
- GRB 231205B: r'-band observations from MISTRAL at Observatoire de Haute-Provence
- GRB 231205B : MITSuME Akeno optical upper limits
- GRB 231205B: Zadko observatory - Gingin optical observations
- GRB 231205B: Gaoyazi/GOT optical upper limit
- GRB 231205B: Nanshan/HMT optical upper limit
- GRB 231205B: GECAM-B detection of a long burst
- GRB 231205B: LCOGT Optical Upper Limits
- GRB 231205B: Enhanced Swift-XRT position
- Swift GRB231205.70: Global MASTER-Net observations report
- GRB 231205B: AKO Optical Upper Limit
- GRB 231205B: Swift detection of a burst
- LIGO/Virgo/KAGRA S231129ac: Upper limits from Swift/BAT-GUANO
- GRB 231203A: Fermi GBM Observation
- GRB 231203A: Swift/BAT-GUANO detection of a burst outside the coded FOV
- Konus-Wind detection of GRB 231129C
- GRB 231129C: Swift-XRT afterglow detection
- GRB 231129C: PROMPT optical upper limits for the MAXI/GSC X-ray counterpart and the MASTER afterglow candidate
- GRB 231129A: VZLUSAT-2 detection
- GRB 231129B: Swift-XRT observations
- GRB 231129C: AGILE detection
- GRB 231129A : MITSuME Akeno optical upper limits
- GRB 231129C: Swift/BAT-GUANO localization of a burst outside the coded FOV
- GRB 231129A: Swift-BAT refined analysis
- GRB 231129C: MASTER OT detection
- GRB 231129A: BOOTES-5/JGT optical upper limit
- GRB 231129A: JinShan optical upper limit
- GRB 231129C: Swift-XRT observations
- GRB 231129A: Swift/UVOT Upper Limits
- GRB 231129A: optical upper limit in Mondy observatory
- GRB 231129C: Tiled Swift observations
- GRB 231129A: Enhanced Swift-XRT position
- GRB 231129A: Swift-XRT refined Analysis
- GRB 231129B: Tiled Swift observations
- GRB 231129A: GECAM-C detection of a long burst
- GRB 231129A: INTEGRAL detection of a long GRB
- GRB 231129A: Swift detection of a burst
- GRB 231123C: Fermi GBM Observation
- GRB 231123B: Fermi GBM Observation
- GRB 231123B: Swift/BAT-GUANO detection of a burst outside the coded FOV
- GRB 231111A: Optical follow-up observations at Terskol, AbAO, Maidanak, Mondy, Assy
- GRB 231123C: Insight-HXMT/HE detection
- GRB 231123C (short): Glowbug gamma-ray detection
- GRB230506B: VIRT optical upper limit
- GRB 231123C: Swift/BAT-GUANO detection of a short burst likely outside the coded FOV
- GRB 231115A: XMM-Newton observation
- GRB 231118A: REM optical afterglow detection
- GRB 231122B: AstroSat CZTI detection
- GRB 231122B: CALET Gamma-Ray Burst Monitor detection
- GRB 231122B: Swift/BAT-GUANO detection of a long burst outside the coded FOV
- GRB 231118A: ATCA detection of radio counterpart
- GRB 231117A: Swift/UVOT late time observations
- GRB 231117A: Swift-BAT refined analysis
- GRB 231118A: GRBAlpha detection
- LIGO/Virgo/KAGRA S231118d: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S231118an: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S231114n: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S231113bb: Upper limits from Swift/BAT-GUANO
- GRB 231118A: VZLUSAT-2 detection
- GRB 231118A: Swift-BAT refined analysis
- GRB 231117A: CALET Gamma-Ray Burst Monitor detection
- 231118A: Swift-UVOT Detection
- GRB231117A: Swift-UVOT detection
- GRB 231118A: Fermi GBM observation
- GRB 231117A: Swift-XRT refined Analysis
- GRB 231118A: Swift-XRT refined Analysis
- GRB 231118A: MeerLICHT afterglow detection
- GRB 231118A: VLT/X-shooter redshift
- GRB 231117A: MAAO 0.7-m telescope optical upper limit
- GRB 231117A: GECAM-C detection
- GRB 231118A: AstroSat CZTI detection
- GRB 231115A: Upper limit from CALET Gamma-Ray Burst Monitor
- GRB 231118A: Las Cumbres optical detection
- GRB 231118A: LCOGT Optical Observations
- GRB 231118A: MASTER OT observation
- Swift GRB231118.72: Global MASTER-Net observations report
- GRB 231118A: Enhanced Swift-XRT position
- GRB 231117A: Kinder observations with Lulin observatory for AT 2023yba without fading in r band
- GRB 231118A: Swift-XRT position
- GRB 231118A: Skynet Optical Afterglow Discovery