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').
- Fermi trigger No 647942198: MASTER optical afterglow detection
- GRB 210704A: Zeiss-1000/SAO-RAS optical observations
- GRB 210715B: DDOTI Upper Limits on the Afterglow
- Fermi trigger No 648033323: Global MASTER-Net observations report
- Fermi trigger No 648024201: Global MASTER-Net observations report
- Fermi trigger No 647942198: Global MASTER-Net observations report
- GRB 210712A: Swift-BAT refined analysis
- GECAM detection of a short burst from SGR J1935+2154
- Recent activity of SGR 1935+2154 as observed by CGBM
- GRB 210712A: Swift-XRT refined Analysis
- GRB 210712A: Swift/UVOT Upper Limits
- GRB 210712A: BOOTES-3/YA optical upper limit
- Fermi trigger No 647805873: Global MASTER-Net observations report
- GRB 210712A: Enhanced Swift-XRT position
- GRB 210704A: classification as long GRB and redshift estimating
- GRB 210704A: Lowell Discovery Telescope Optical Observations
- Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 10
- GECAM detection of a short burst from SGR J1935+2154
- Fermi trigger No 647775795: Global MASTER-Net observations report
- GRB 210712A: Swift detection of a burst
- GRB 210709A: AstroSat CZTI detection
- GRB 210704A: Continued Gemini-North NIR K-band Detections
- GRB 210704A: INTEGRAL observations
- GRB 210704A: NOT optical observations and color change
- GRB210704A: Gemini near-infrared upper limits
- Fermi trigger No 647653174: Global MASTER-Net observations report
- GRB 210704A: Assy optical afterglow upper limit
- Fermi trigger No 647641569: Global MASTER-Net observations report
- Fermi trigger No 647624281: Global MASTER-Net observations report
- GECAM detection of a short burst from SGR J1935+2154
- GRB 210704A: OSIRIS/GTC Observations and Archival Detection of the Possible Host Galaxy
- MAXI GRB210709.93: Global MASTER-Net observations report
- Fermi trigger No 647522278: Global MASTER-Net observations report
- GRB 210704A: Gemini-North Infrared Source Detection
- GRB 210704A: further TNG optical observations
- GRB 210706A: Swift/XRT afterglow confirmation
- GECAM detection of a short burst from SGR 1935+2154
- GRB 210708B: Swift-BAT refined analysis
- Fermi GRB 210709A: Global MASTER-Net observations report
- GRB 210709A: Fermi GBM Final Real-time Localization
- Swift GRB 210708B: Global MASTER-Net observations report
- GRB 210708A: Swift/UVOT Upper Limits
- GRB 210702A: ATCA detection
- GRB 210702A: ALMA detection
- GRB 210708A: Swift-BAT refined analysis
- Fermi GBM Sub-Threshold Detection of GRB 210708A
- Fermi GBM Sub-Threshold Detection of GRB 210707A
- IceCube-210629A - Spectroscopic observation of AT2021osi
- Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 7
- GRB 210708B: Swift detection of a possible burst
- GRB 210708A: Swift-XRT refined Analysis
- GECAM detection of a short burst from SGR 1935+2154
- GRB 210707A: A long GRB detected by INTEGRAL
- GRB 210708A: Swift detection of a burst
- Swift GRB210708.10: Global MASTER-Net observations report
- GRB 210704A: CAHA 2.2m telescope optical limit
- Fermi trigger No 647365516: Global MASTER-Net observations report
- Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 6
- Fermi trigger No 647271699: Global MASTER-Net observations report
- Fermi GBM Observations of SGR J1935+2154
- Swift-BAT detection of a burst from SGR 1935+2154
- GRB 210706A: Fermi GBM observation
- GRB 210706A: optical upper limit of Sintesz-Newton/CrAO and AS-32/AbAO
- Konus-Wind detection of GRB 210706A
- GRB 210706A: GIT optical upper limits
- GRB 210704A: OAJ T80 multi-color detections
- GECAM detection of a bright short burst from SGR 1935+2154
- GRB 210706A: Swift-XRT afterglow detection
- Integral GRB210707.02: Global MASTER-Net observations report
- GRB 210706A: Swift ToO observations
- Fermi trigger No 647252274: Global MASTER-Net observations report
- INTEGRAL detection of a burst from SGR 1935+2154
- Integral GRB210706.72: Global MASTER-Net observations report
- GRB 210706A: Swift/BAT-GUANO detection and arcminute localization
- GRB 210704A: OSIRIS/GTC spectroscopy
- GRB 210704A: CAHA 2.2m Afterglow Detection
- GRB 210704A: RATIR optical upper limits
- GRB 210704A: Swift/UVOT Upper Limits
- Konus-Wind detection of GRB 210704A
- GRB 210704B: AstroSat CZTI detection
- GRB 210619B: ALMA detection
- GRB 210704A: TNG detection of the optical afterglow candidate
- GRB 210704A: Assy optical afterglow candidate
- GRB 210704A: DDOTI upper limit
- GRB 210704B: Fermi GBM detection
- GRB 210704A: possible local hosts
- GRB 210704A: Fermi GBM detection
- GRB 210704A: Swift-XRT afterglow detection
- GRB 210704A: AstroSat CZTI detection
- IceCube-210516A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- IceCube-210510A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- GRB 210704A: Fermi-LAT detection
- GRB 210704A: Swift ToO observations
- GRB 210705A: AGILE/MCAL detection of a burst
- GRB 210704A: AGILE/MCAL detection
- Fermi trigger No 647108723: Global MASTER-Net observations report
- Fermi trigger No 647120009: Global MASTER-Net observations report
- GRB 210704A: BALROG localization (Fermi Trigger 647120009 / GRB 210704815)
- GRB 210702A, Swift-BAT refined analysis
- GRB 210702A: BOOTES-3/YA optical counterpart observations