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.
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
770 results found.
- LIGO/Virgo/KAGRA S240422ed: Coverage and upper limits from MAXI/GSC observations
- GRB 240309A: MAXI/GSC detection
- GRB 240225B: Swift-XRT afterglow detection
- GRB 240225B: Glowbug gamma-ray detection
- GRB 240225B: Swift ToO observations
- Konus-Wind detection of GRB 240225B (long)
- GRB 240225B: VLT/X-shooter redshift
- GRB 240225B : MITSuME Akeno optical afterglow candidate detection
- GRB 240225B: 3.6m DOT observation
- GRB 240225B: NOT optical observations
- GRB 240225B: Nanshan/HMT optical afterglow detection
- GRB 240225B: CALET Gamma-Ray Burst Monitor detection
- GRB 240225B: Swift-XRT observations
- GRB 240225B: GOTO detection of a candidate optical afterglow
- GRB 240225B: AstroSat CZTI detection
- GRB 240225B: Tiled Swift observations
- GRB 240225B: MAXI/GSC detection
- GRB 240128A: Further Swift-XRT observations
- GRB 240214A: Tiled Swift observations
- GRB 240214A/1H 0451-560: MAXI/GSC detection
- GRB 240128A: Glowbug gamma-ray detection
- GRB 240128A: Swift-XRT observations
- GRB 240128A: GRBAlpha detection
- GRB 240128A: Tiled Swift observations
- GRB 240128A: CALET Gamma-Ray Burst Monitor detection
- GRB 240128A: MAXI/GSC detection
- GRB 240122A: ATCA detection of radio counterpart
- GRB240122A: PRIME near infrared detection
- GRB 240122A: Swift/UVOT Upper Limits
- GRB 240122A: BOOTES-2/TELMA optical upper limit and 1.5m OSN detection
- Swift GRB240123.46: Global MASTER-Net observations report
- GRB 240122A: Swift-XRT afterglow detection
- GRB 240122A: VLT/X-shooter redshift confirmation
- GRB 240122A: Redshift from OSIRIS+/GTC
- GRB 240122A: LT non-detection of GOTO candidate counterpart confirms fading
- GRB 240122A: GOTO optical counterpart candidate
- GRB 240122A: Tiled Swift observations
- GRB 240122A: MAXI/GSC detection
- GRB 240107A: VZLUSAT-2 detection
- GRB 240114A: MAXI/GSC detection
- GRB 240107A: AstroSat CZTI detection
- GRB 240107A: MAXI/GSC detection
- IPN triangulation of GRB 231129C
- GRB 231129C: ASIM MXGS observation and localization
- Konus-Wind detection of GRB 231129C
- GRB 231129C: PROMPT optical upper limits for the MAXI/GSC X-ray counterpart and the MASTER afterglow candidate
- GRB 231129B: Swift-XRT observations
- GRB 231129C: AGILE detection
- GRB 231129C: Swift/BAT-GUANO localization of a burst outside the coded FOV
- GRB 231129C: MASTER OT detection
- GRB 231129C: Fermi-LAT detection
- GRB 231129C: GRBAlpha detection
- GRB 231129C: Glowbug gamma-ray detection
- GRB 231129C: GECAM-B detection of a bright burst
- GRB 231129C: AstroSat CZTI detection
- GRB 231129C: CALET Gamma-Ray Burst Monitor detection
- GRB 231129C: Fermi GBM Observation of a very bright GRB
- GRB 231129C: iTelescope likely optical afterglow AT 2023yph discovery
- GRB 231129C: MAXI/GSC detection
- GRB 231129B: Tiled Swift observations
- GRB 231129B: MAXI/GSC detection
- LIGO/Virgo/KAGRA S231119ab: Coverage and upper limits from MAXI/GSC observations
- GRB 231115A: GBM/Fermi Observations of a probable Giant Flare of Magnetar
- LIGO/Virgo/KAGRA S231113cd: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S231113bw: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S231021az: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S231020ba: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S230917af: GRAWITA wide-field observations
- LIGO/Virgo/KAGRA S230917af: Zwicky Transient Facility observations
- LIGO/Virgo S230917af: Swift XRT observations, 6 X-ray sources
- LIGO/Virgo/KAGRA S230917af: MAXI/GSC observations
- Trigger 1187142: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
- MAXI/GSC detection of Swift J1727.8-1613 (GRB 230824A)
- LIGO/Virgo/KAGRA S230802aq: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S230731an: Coverage and upper limits from MAXI/GSC observations
- IceCube-230707A : MAXI upper limit and NICER follow-up observation of Swift J1753.5-0127
- Konus-Wind detection of GRB 220623A
- LIGO/Virgo/KAGRA S230627c: Coverage and upper limits from MAXI/GSC observations
- GRB 230623A: Swift-XRT observations
- GRB 230623A: Tiled Swift observations
- MAXI GRB 230623A: MASTER optical observations
- GRB 230623A: Tiled Swift observations
- GRB 230623A: MAXI/GSC detection
- LIGO/Virgo/KAGRA S230529ay: Coverage and upper limits from MAXI/GSC observations
- GRB 230520A: CALET Gamma-Ray Burst Monitor detection
- GRB 230520A: MAXI/GSC detection
- LIGO/Virgo/KAGRA S230518h: Coverage and upper limits from MAXI/GSC observations
- GRB 230510B: Fermi GBM detection
- GRB 230510B: AstroSat CZTI detection
- GRB 230510B: CALET Gamma-Ray Burst Monitor detection
- GRB 230510B: MAXI/GSC detection
- MAXI GRB230408.82: Global MASTER-Net observations report
- GRB 230307A: soft X-ray detection with LEIA
- GRB 230307A: MAXI/GSC upper limit
- GRB 230220A: Correction to GCN 33352
- GRB 230220A: MAXI/GSC detection
- GRB 230204B: CALET Gamma-Ray Burst Monitor detection
- GRB 230204B: ATCA radio detection
- GRB 230204B: MASTER early OT detection
- GRB 230204B: Swift/UVOT Upper Limits