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').
- GRB 231117A: Swift-XRT refined Analysis
- GRB 231118A: Swift-XRT refined Analysis
- GRB 231118A: MeerLICHT afterglow detection
- LIGO/Virgo/KAGRA S231119u: One counterpart neutrino candidate from IceCube neutrino searches
- GRB 231117A: OHP/T120 optical observations
- GRB 231118A: VLT/X-shooter redshift
- Fermi trigger No 722039659: Global MASTER-Net observations report
- GRB 231117A: Pan-STARRS1 follow-up confirms rapid fading
- LIGO/Virgo/KAGRA S231119u: Identification of a GW compact binary merger candidate
- GRB 231117A: MAAO 0.7-m telescope optical upper limit
- GRB 231117A: AKO Follow-Up Observation
- GRB 231117A: GECAM-C detection
- GRB 231118A: AstroSat CZTI detection
- GRB 231115A: Upper limit from CALET Gamma-Ray Burst Monitor
- GRB 231117A: 10 GHz VLA detection
- GRB 231118A: Las Cumbres optical detection
- GRB 231118B: BALROG localization (Fermi Trigger 722039659 / GRB 231118940)
- GRB 231118B: Fermi GBM Final Real-time Localization
- GRB 231118A: LCOGT Optical Observations
- GRB 231118A: MASTER OT observation
- GRB 231118A: Continued Skynet Observations
- 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 231117A: SOAR/Goodman imaging of the afterglow
- GRB 231118A: Swift detection of a burst
- GRB 231118A: Fermi GBM Final Real-time Localization
- GRB 231117A: Lowell Discovery Telescope Observations
- GRB 231117A: ePESSTO+ host galaxy redshift confirmation
- GRB 231117A: ATCA detection of a radio counterpart
- LIGO/Virgo/KAGRA S231118an: Identification of a GW compact binary merger candidate
- GRB 231117A: GRBAlpha detection
- LIGO/Virgo/KAGRA S231118ab: Identification of a GW compact binary merger candidate
- GRB 231117A: Keck spectroscopy of afterglow candidate
- GRB 231115A: Wendelstein Optical/Infrared Observations
- GRB 231115A: JinShan optical upper limits
- LIGO/Virgo/KAGRA S231118d: Identification of a GW compact binary merger candidate
- GRB 231117A: GIT optical follow-up
- GRB 231117A: LT observations consistent with fading
- GRB 231117A: Keck observations indicate presence of optical afterglow in z~0.3-0.5 galaxy
- GRB 231117A: REM optical and NIR early-time observations
- GRB231117A: AGILE/MCAL analysis
- 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 : OHP/T120 optical upper limit
- 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 231115A: Non-detection of radio emission with CHIME/FRB
- GRB 231111A: Swift/UVOT Detection
- MAGIC observation of GRB 231115A, a possible magnetar giant flare
- GRB231115A: Liverpool Telescope imaging
- GRB 231115A: NuSTAR Follow-Up Observations
- GRB 231115A: Swift/BAT-GUANO detection of a short burst
- GRB 231115A: Swift-XRT and Swift-UVOT observations
- Fermi GRB 231116A: Global MASTER-Net observations report
- Konus-Wind detection of GRB 231115A (a probable Magnetar Giant Flare from M82)
- GRB 231115A: AGILE/MCAL upper limits
- GRB 231115A: Insight-HXMT/HE detection
- GRB 231115A: GBM/Fermi Observations of a probable Giant Flare of Magnetar
- GRB 231116A: Fermi GBM Final Real-time Localization
- GRB 231115A : MITSuME Akeno and Okayama optical upper limits
- GRB 231115A: Gaoyazi/GOT follow-up and archival observations
- GRB 231115A / AT2023xvj: Updated GIT analysis
- GRB 231115A: archival Chandra X-ray observations
- GRB 231115A: Upper limits from a neutrino search with IceCube
- GRB 231115A: Kinder observations with Lulin observatory
- GRB231115A: GRANDMA Observations
- GRB 231115A: GOTO pre-burst limits of AT2023xvj
- GRB 231115A: Non-detection in low-latency of gravitational waves with LIGO/Virgo/KAGRA
- GRB 231115A: pre-burst ZTF upper limits for GRB optical counterpart candidate
- GRB 231106A: TESS identification of candidate optical counterpart
- GRB 231115A: MASTER optical observations
- GRB 231115A (short): Glowbug gamma-ray detection
- GRB 231115A: Fermi Observations of a probable Magnetar Giant Flare from M82
- GRB 231115A: archival HST observations
- Integral GRB231115.65: Global MASTER-Net observations report
- GRB 231115A: GROWTH-India discovery of a potential optical counterpart
- GRB 231115A: Swift ToO observations
- Fermi GRB 231115A: Global MASTER-Net observations report
- GRB 231115A: significance of INTEGRAL localization alignment with M82
- GRB 231115A: a short hard GRB detected by IBAS, poistionally coincident with M82
- GRB 231115A position consistent with M 82 galaxy
- GRB 231115A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S231113bw: Updated Sky localization, EM Bright Classification, and Source Classification
- GRB 231111A: Swift-BAT refined analysis
- LIGO/Virgo/KAGRA S231113bw: Zwicky Transient Facility observations
- LIGO/Virgo/KAGRA S231114n: Updated Sky localization
- Fermi GRB 231114A: Global MASTER-Net observations report
- GRB 231113A (short): Glowbug gamma-ray detection