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 230723B: GAD Observatory, La Spezia, Italy upper limit
- IPN triangulation of GRB 230723A (short)
- Fermi Gamma-ray Burst Monitor trigger 711982704/230725540 is not a GRB
- GRB 230725B: Fermi GBM Final Real-time Localization
- GRB 230725A: Fermi GBM Final Real-time Localization
- GRB 230723B: Leavitt Observatory upper limit
- GRB 230723B: Osservatorio Astronomico Nastro Verde upper limit
- GRB 230723B: Montarrenti Observatory upper limit
- GRB 230723B: Optical afterglow candidate from CAHA
- GRB 230723B: Bassano Bresciano Observatory upper limit
- GRB 230723B: Fermi GBM observation
- GRB 230723B: Swift-XRT refined Analysis
- GRB 230723B: non-detections from Observatoire de Haute-Provence
- IceCube Alert 230724.08: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S230723ac: Updated Sky localization
- Fermi trigger No 711853834: Global MASTER-Net observations report
- GRB 230724A: Fermi GBM Final Real-time Localization
- Fermi trigger No 711805358: Global MASTER-Net observations report
- GRB 230723B: Optical limit from CAHA
- GRB 230723B: Swift/UVOT Upper Limits
- Swift GRB 230723B: Global MASTER-Net observations report
- Swift-XRT position for GRB 230723B
- GRB 230723A: AGILE/MCAL detection
- GRB 230723B: Swift-XRT observations
- LIGO/Virgo/KAGRA S230723ac: Identification of a GW compact binary merger candidate
- GRB 230723B: Swift detection of a burst
- Fermi GRB 230723A: Global MASTER-Net observations report
- GRB 230723A: Fermi GBM Final Real-time Localization
- Swift GRB230720.30: Global MASTER-Net observations report
- IPN triangulation of GRB 230715D
- Swift Trigger 1180063 is not a GRB
- Swift Trigger 1180060 is not a GRB
- Swift Trigger 1180055 is not a GRB
- GRB 230718A: Final Localization Correction
- GRB 230718A: Fermi GBM Final Real-time Localization
- Fermi Gamma-ray Burst Monitor trigger 711329677/230717982 is not a GRB
- IPN triangulation of GRB 230712C (short)
- IPN triangulation of GRB 230712A (short)
- LIGO/Virgo/KAGRA S230708z: Updated Sky localization
- GRB 230717A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S230715bw: Retraction of GW compact binary merger candidate
- Fermi trigger No 711088412: Global MASTER-Net observations report
- GRB 230715A: Fermi GBM Final Real-time Localization
- Fermi GRB 230713A: Global MASTER-Net observations report
- IceCube-230707A : MAXI upper limit and NICER follow-up observation of Swift J1753.5-0127
- GRB 230713A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S230709bi: Updated Sky localization
- LIGO/Virgo/KAGRA S230708t: Updated Sky localization
- GRB 230709B: CALET Gamma-Ray Burst Monitor detection
- GRB 230703A: CALET Gamma-Ray Burst Monitor detection
- GRB 230709C: Swift/BAT-GUANO detection of a short burst outside the coded FOV
- IceCube-230708A: Upper limits from Swift/BAT-GUANO
- GRB 230712B: Fermi GBM Final Localization
- LIGO/Virgo/KAGRA S230712a: Retraction of GW compact binary merger candidate
- GRB 230707A: Swift/BAT-GUANO position correction
- GRB 230712A: Fermi GBM Final Real-time Localization
- IceCube-230708A - Correction to GCN Circular 34170
- Fermi trigger No 710741042: Global MASTER-Net observations report
- GRB 230709C: GRBAlpha detection
- GRB 230709B: GRBAlpha detection
- GRB 230709C: Fermi GBM Detection
- GRB 230709C: Fermi GBM Final Localization
- GRB 230707B: Fermi GBM Observation
- GRB 230710A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S230708z: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230708t: Identification of a GW compact binary merger candidate
- IceCube-230707A: No candidates detected by Swift-XRT
- Swift Trigger 1178410 is not an astrophysical event
- GRB 230709C: AstroSat CZTI detection
- LIGO/Virgo/KAGRA S230708cf: Updated Sky localization
- GRB 230707B: CALET Gamma-Ray Burst Monitor detection
- GRB 230703A detected with multiple GRID detectors
- GRB 230709C: BALROG localization (Fermi Trigger 710617111 / GRB 230709735)
- LIGO/Virgo/KAGRA S230707ai: Updated Sky localization
- IceCube-230707A: No candidates from the Zwicky Transient Facility
- Fermi-LAT gamma-ray observations of IceCube-230708A
- Fermi-LAT gamma-ray observations of IceCube-230707B
- Fermi-LAT gamma-ray observations of IceCube-230707A
- LIGO/Virgo/KAGRA S230630am: Updated Sky localization
- LIGO/Virgo/KAGRA S230630am: Updated Sky localization
- GRB 230709B: BALROG localization (Fermi Trigger 710614579 / GRB 230709706)
- IceCube-230708A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-230707B: Upper limits from a search for additional neutrino events in IceCube
- IceCube-230707A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S230709bi: Identification of a GW compact binary merger candidate
- Swift Trigger 1178410: possible GRB 230709A
- LIGO/Virgo/KAGRA S230708cf: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230708bi: Retraction of GW compact binary merger candidate
- GRB 230628C: GRID Detection
- IceCube-230708A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 230707B: Swift/BAT-GUANO detection of a burst outside the coded FOV
- GRB 230707A: Swift-XRT observations
- IceCube Alert 230708.35: Global MASTER-Net observations report
- IceCube-230707B - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 230707B: Fermi GBM Final Real-time Localization
- IceCube Alert 230707.71: Global MASTER-Net observations report
- IceCube-230707A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 230707A: Fermi GBM Detection
- LIGO/Virgo/KAGRA S230707ai: Identification of a GW compact binary merger candidate
- GRB 230707A: Swift ToO observations