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"19539 results found.
- 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
- GRB 231118A: Swift detection of a burst
- GRB 231117A: GRBAlpha detection
- GRB 231117A: GIT optical follow-up
- GRB 231117A: AKO Optical Upper Limit
- GRB 231117A: afterglow candidate detection from Kinder observations with Lulin observatory
- Swift GRB 231117A: Global MASTER-Net observations report
- GRB 231117A (short): Glowbug gamma-ray detection
- GRB 231117A: ATLAS non-detection of an optical counterpart
- Konus-Wind detection of GRB 231117A (short/hard)
- GRB 231115A: optical observations from INAF observatories
- GRB 231117A : MITSuME Akeno optical upper limits
- GRB 231117A: AGILE detection of a bright short burst
- GRB 231117A: Enhanced Swift-XRT position
- GRB 231117A: GOTO optical upper limits
- GRB 231117A: AstroSat CZTI detection of a bright short burst
- GRB 231117A: Swift detection of a bright short burst
- GRB 231111A: Swift/UVOT Detection
- GRB 231115A: Swift/BAT-GUANO detection of a short burst
- GRB 231115A: Swift-XRT and Swift-UVOT observations
- GRB 231115A: Swift ToO observations
- GRB 231111A: Swift-BAT refined analysis
- GECAM-B observation of a short burst from SGR J1555-5402
- SGRJ1555-5402: Swift/BAT-GUANO arcminute localization of a SGR flare
- GRB 231110A: CALET Gamma-Ray Burst Monitor detection
- GRB 231110A: Swift-BAT refined analysis
- GRB231111A: MDM 2.4m Hiltner Telescope Observation
- GRB 231111A: Xinglong-2.16m optical observations
- GRB 231110A: Swift-UVOT Upper Limits
- GRB 231104A: VZLUSAT-2 detection
- GRB 231110A: Glowbug gamma-ray detection
- GRB 231110A: AstroSat CZTI detection
- GRB 231111A: Leavitt Observatory optical observations
- GRB231111A: Optical follow-up observations with Mephisto
- GRB 231111A: Osservatorio Astronomico "Nastro Verde" optical observations with detection of an optical counterpart
- GRB 231110A: Terskol Zeiss-2000 optical upper limit
- GRB 231111A: Swift-XRT refined Analysis
- GRB 231111A: Mondy optical observations
- GRB 231111A: GECAM-C detection of a long burst (correction)
- GRB 231110A: GECAM-B detection (correction)
- GRB 231111A: Enhanced Swift-XRT position
- GRB 231111A: GECAM-C detection of a long burst
- GRB 231110A: GECAM detection
- GRB 231110A: SAO RAS optical observations
- GRB 231110A: Swift-XRT afterglow detection
- GRB231111A: YAHPT Observations
- GRB231111A: GIT confirmation of the optical afterglow
- GRB 231111A: MASTER OT earlier detection
- GRB 231111A: Nanshan/HMT optical observations
- GRB 231111A: Swift detection of a burst with an optical counterpart
- Swift GRB231111.60: Global MASTER-Net observations report
- GRB231110A: WFST Observation and upper limits
- Swift GRB231110.89: Global MASTER-Net observations report
- GRB 231110A: Swift detection of a burst
- GRB 231104A: Swift-BAT refined analysis
- GRB 231104A: FRAM-ORM optical limit
- LIGO/Virgo/KAGRA S231102w: Upper limits from Swift/BAT-GUANO
- GRB 231104A: NuSTAR Observation of the prompt emission
- GRB 231104A: 3.6m DOT optical upper limit
- GRB 231104A: NOT upper limit
- GRB 231104A: Fermi GBM Observation
- GRB 231104A: AKO Upper Limit