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').
Advanced Search
To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.
Advanced Search Examples (click to copy):
subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
6097 results found.
- Fermi GRB 220211A: Global MASTER-Net observations report
- Fermi-LAT Gamma-ray Observations of IceCube-220205B
- Fermi-LAT Gamma-ray Observations of IceCube-220205A
- Fermi-LAT Gamma-ray Observations of IceCube-220202A
- GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
- GRB 220117A: Konus-Wind detection and joint Konus-Wind + Swift-BAT spectral analysis
- GRB 220118A: Fermi GBM detection
- GRB 220118A: GIT optical observations
- GRB 220118A: Enhanced Swift-XRT position
- GRB 220118A: MITSuME Akeno optical observation
- Fermi-LAT Gamma-ray Observations of IceCube-220115A and detection of a new gamma-ray source, Fermi J2350.2+2620
- GRB 220117B: Swift-XRT refined Analysis
- GRB 220117A: Swift-XRT refined Analysis
- Konus-Wind detection of GRB 220101A
- GRB 220107A: SAO RAS optical observations
- Konus-Wind detection of GRB 220107A
- Confirmation of the X-ray afterglow of GRB 220107B
- GRB 220107A: further SAO RAS optical observations
- GRB 220107A: SAO RAS optical observations
- GRB 220101A: SAO RAS optical observations
- GRB 220107A: Swift/UVOT Detection
- GRB 220107B: Fermi GBM observations
- GRB 220107B: Swift-XRT afterglow detection
- GRB 220107A: Swift-XRT afterglow detection
- GRB 220107B: Fermi-LAT detection
- GRB 220107A: Fermi GBM observations
- GRB 220101A: continued 1.3m DFOT Optical Observations
- GRB 220104A: Fermi GBM Observation
- GRB 220101A: 2.2m CAHA (+CAFOS) first day optical detection
- GRB 220101A: iTelescope optical observations
- GRB 220101A: 1.3m DFOT observations
- GRB 211229B: Fermi GBM observation
- Alert from the HAWC Burst Monitor HAWC-220103A
- GRB 220101A: Swift-XRT refined Analysis
- GRB 220101A: Fermi-LAT detection
- GRB 211229A: Swift-XRT and UVOT observations
- GRB 211229A: Fermi GBM observation
- GRB 211227A: Swift-XRT refined Analysis
- GRB 211221A: Swift-XRT refined Analysis
- IceCube-211216B: No significant detection in HAWC
- IceCube-211216A: No significant detection in HAWC
- GRB 211216A: Fermi GBM observation
- GRB 211106A: XMM-Newton monitoring campaign detections
- Fermi-LAT Gamma-ray Observations of IceCube-211216B
- Fermi-LAT Gamma-ray Observations of IceCube-211216A
- IceCube-211216A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- GRB 211211A: HCT and GIT optical follow up observations
- GRB 211211A: Swift-XRT refined Analysis
- GRB 211211A: Fermi GBM observation
- IceCube-211208A: No significant detection in HAWC
- Fermi-LAT Gamma-ray Observations of IceCube-211208A
- IceCube-211208A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- Chandra observation of GW170817 at ~1573 days since merger (Epoch 1 of 4)
- GRB 211204C: Fermi GBM detection
- GRB 211207A: Swift-XRT refined Analysis
- GRB 211206A: AstroSat CZTI detection
- GRB 211124A: Fermi GBM Observation
- IceCube-211125A: No significant detection in HAWC
- GRB 211129A: Swift-XRT refined Analysis
- GRB 211129A: Fermi GBM observation
- IceCube-211125A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- GRB 211023A: Xinglong 2.16m optical observations
- Fermi-LAT Gamma-ray Observations of IceCube-211125A
- GRB 211120548: Fermi GBM observation
- Chandra observations of GRB 210905A
- GRB 211118A: Fermi GBM detection
- Fermi-LAT Gamma-ray Observations of IceCube-211123A
- HAWC-211123A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- Fermi-LAT Gamma-ray Observations of IceCube-211117A
- Fermi-LAT Gamma-ray Observations of IceCube-211116A
- Fermi trigger No 658755664: Global MASTER-Net observations report
- GRB 211023A: classification and SPI-ACS/INTEGRAL registration
- GRB 211106A: Swift/UVOT upper limits
- GRB 211107B: Swift-XRT afterglow detection
- GRB 211106A: Swift-XRT afterglow detection
- GRB 211023A: SAO RAS optical observations
- GRB 211107B: Swift-XRT observations
- GRB 211106A: Swift-XRT observations
- Swift Trigger 1082569 is probably not a GRB
- GRB 211023A: continued 1.3m DFOT Optical Observations and possible jet break
- GRB 211023A: 1.3m DFOT Optical Observations
- GRB 211024A: Swift-XRT source 4 is not an afterglow.
- GRB 211023B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
- GRB 211024A: Possible afterglow candidate from GIT
- GRB 211024A: Swift-XRT observations
- GRB 211024A: Fermi GBM detection
- GRB 211018A: Swift-XRT observations
- GRB 211025A: Swift-XRT refined Analysis
- GRB 211024B: CAHA 2.2m Detection; ultra-long GRB?
- GRB 211024B: Swift-XRT refined Analysis
- GRB 210610B: Sintesz-Newton/CrAO optical observations
- GRB 211025A: Swift detection of a burst
- GRB 211023A: OAJ Bright Afterglow Confirmation
- Fermi-LAT Gamma-ray Observations of IceCube-211023A
- IceCube-211023A: No neutrino counterpart detected with ANTARES
- GRB 211023B: Swift-XRT refined Analysis
- GRB 211023A: Fermi-LAT detection
- GRB 211018A: Fermi GBM observation
- GRB 211018A: Fermi-LAT detection
- GRB 210928A: Kinder SLT-40cm optical limits