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 230328B: GIT optical follow-up
- GRB 230328B: OASDG optical observations
- GRB 230328B: Nanshan/NEXT optical upper limit
- GRB 230328B: Swift-XRT refined Analysis
- GRB 230328B: AstroSat CZTI detection
- GRB 230328B: Fermi GBM observation
- GRB 230328B: Mondy, AbAO and Kitab optical observations
- GRB 230328B: Enhanced Swift-XRT position
- GRB 230328B: Mondy optical afterglow confirmation
- GRB 230328B: Swift detection of a burst with an optical afterglow
- GRB 230328B: Fermi GBM Final Real-time Localization
- Fermi GRB 230328A: Global MASTER-Net observations report
- GRB 230328A: Fermi GBM Final Real-time Localization
- GRB 230325A: Swift-BAT refined analysis
- GRB 230325A: Swift/UVOT Upper Limits
- GRB 230325A: X-shooter optical afterglow and redshift
- GRB 230325A: Swift-XRT refined Analysis
- GRB 230322B: Swift-BAT refined analysis
- GRB 230325A: Enhanced Swift-XRT position
- GRB 230325A: Prompt enhanced Swift-XRT position
- GRB 230325A: Swift detection of a burst
- GRB 230320B: Fermi GBM Observation
- Fermi trigger No 701313046: Global MASTER-Net observations report
- Fermi trigger No 701321709: Global MASTER-Net observations report
- GRB 230322B: Swift/UVOT Detection
- Konus-Wind detection of GRB 230309A
- Konus-Wind detection of GRB 230308A
- Konus-Wind detection of GRB 230304B
- GRB 230322B: Swift-XRT refined Analysis
- GRB 230322B: Enhanced Swift-XRT position
- Swift GRB 230322B: Global MASTER-Net observations report
- GRB 230322B: Swift detection of a burst with optical counterpart
- GRB 230322A: Fermi GBM Final Real-time Localization
- GRB 230320B: GRBAlpha detection
- GRB 230321A: CALET Gamma-Ray Burst Monitor detection
- GRB 230320B: CALET Gamma-Ray Burst Monitor detection
- Fermi trigger No 701071944: Global MASTER-Net observations report
- GRB 230320B: Swift/BAT-GUANO detection outside the coded FOV
- Fermi GRB 230320A: Global MASTER-Net observations report
- Fermi GRB 230321A: Global MASTER-Net observations report
- Fermi trigger No 701058254: Global MASTER-Net observations report
- SGR 1806-20: Correction to GCN 33494
- INTEGRAL detection of a burst from SGR 1806-200
- GRB 230321B: AstroSat CZTI detection
- GRB 230320B: AstroSat CZTI detection
- GRB 230321A: BALROG localization (Fermi Trigger 701065308 / GRB 230321182)
- GRB 230321A: Fermi GBM Final Real-time Localization
- GRB 230320A: Fermi GBM Final Real-time Localization
- GRB 230314A: TURBO Optical Upper Limit
- Trigger 1160641: Swift detection of 4U 1630-472 (a.k.a. SWIFT J1633.8-4724A)
- Fermi trigger No 700976129: Global MASTER-Net observations report
- GRB 230307A: Continued Gemini-South observations confirm rapid optical fading
- IPN triangulation of GRB 230309A
- Fermi GRB 230316A: Global MASTER-Net observations report
- GRB 230304D: AstroSat CZTI detection
- GRB 230316A: Fermi GBM Final Real-time Localization
- IPN triangulation of GRB 230304B
- GRB 230313A: AstroSat CZTI detection
- GRB 230307A: Far off-axis NuSTAR detection of the GRB
- IPN triangulation of GRB 230308A (short/bright)
- Fermi GRB 230314A: Global MASTER-Net observations report
- GRB 230307A: ATCA radio detection
- GRB 230314A: Fermi GBM Final Real-time Localization
- VZLUSAT-2 detection of SGR 1806-20
- GRB 230307A: INTEGRAL upper limit on Hard X-ray afterglow
- GRB 230307A: Swift/UVOT detection
- AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-230313A
- GRB 230313A: BALROG localization (Fermi Trigger 700400328 / GRB 230313485)
- Fermi GRB 230313A: Global MASTER-Net observations report
- GRB 230313A: Fermi GBM Final Real-time Localization
- GRB 230307A: soft X-ray detection with LEIA
- GRB 230307A: Swift-XRT afterglow detection
- GRB 230309A: AstroSat CZTI detection of a bright long GRB
- Swift GRB230311.85: Global MASTER-Net observations report
- Swift GRB230311.83: Global MASTER-Net observations report
- Further improved IPN localization for GRB 230307A
- Swift GRB230311.81: Global MASTER-Net observations report
- GRB 230307A: SOAR/Goodman detection of the possible host galaxy
- Swift GRB230311.84: Global MASTER-Net observations report
- Swift Trigger 1159438 is also due to the Star Tracker loss of lock.
- Swift GRB230311.82: Global MASTER-Net observations report
- Triggers 1159434, 1159435 and 1159437: Swift detection of Sco X-1 due to Star Tracker loss of lock
- Alert from the HAWC Burst Monitor HAWC-230311A
- TESS Detection of the Optical Afterglow of GRB230307A
- GRB 230308A: CALET Gamma-Ray Burst Monitor detection
- Trigger 1159327: Swift detection of SGR1806-20
- GRB 230310A: AstroSat CZTI detection
- GRB 230307A: GECKO optical observations and detections of the afterglow
- GRB 230307A: MAXI/GSC upper limit
- GRB 230307A: Gemini-South Confirmation of the Optical Afterglow
- Fermi GRB 230310A: Global MASTER-Net observations report
- GRB 230310A: Fermi GBM Final Real-time Localization
- GRB 230307A: AGILE/MCAL analysis
- GRB 230307A: ATLAS information on the ULTRACAM optical afterglow candidate
- GRB 230307A: Erratum of the GCN 33441
- GRB 230204B: MASTER detection of an object near NTT Optical Afterglow Candidate
- GRB 230308A: Fermi GBM detection
- GRB 230307A: Possible optical afterglow
- GRB 230307A: ASO-S/HXI detection
- GRB 230307A: AstroSat LAXPC detection