GCN Circulars
GCN Circulars are rapid bulletins submitted by and distributed to the community. See the documentation for help with subscribing to or submitting Circulars.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
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"- GRB 200703B: Fermi GBM Final Real-time Localization
- GRB 200703A: Fermi GBM Final Real-time Localization
- Fermi GRB 200702A: Global MASTER-Net observations report
- GRB 200702A: Fermi GBM Final Real-time Localization
- Trigger 980513: Swift detection of SGR Swift J1818.0-1607
- GRB 200701A: Swift-BAT refined analysis
- Fermi-GBM Sub-Threshold Detection of GRB 200701A
- GRB 200701A: Swift detection of a burst
- GRB 200630A: Swift-BAT refined analysis
- GRB 200630A: Swift/UVOT Upper Limits
- GRB 200630A: Swift-XRT refined Analysis
- GRB 200630B: Fermi GBM Final Localization
- GRB 200623A: Swift XRT further observations
- GRB 200630A: Fermi GBM detection
- GRB 200629A: AstroSat CZTI detection
- GRB 200630A: Enhanced Swift-XRT position
- GRB 200630A: Swift detection of a burst
- Fermi trigger No 615174580: Global MASTER-Net observations report
- Fermi GRB 200629A: Global MASTER-Net observations report
- GRB 200629A: Fermi GBM Final Real-time Localization
- GRB 200629A: BALROG localization (Fermi Trigger 615127794 / GRB 200629535)
- GRB 200522A: Gemini North spectroscopy of the putative host galaxy
- Konus-Wind detection of short/hard GRB 200623B
- GRB 200623A: Further MMTCam Observations of XRT Source #3
- GRB 200625A: Fermi-LAT detection is likely a flare from PKS 1127-14
- GRB 200623A: LBT optical observations
- GRB 200623A : SMA observations at Swift/XRT Source #3
- Fermi GRB 200626A: Global MASTER-Net observations report
- GRB 200625A: Swift ToO observations
- GRB 200626A: Fermi GBM Final Real-time Localization
- Fermi GRB 200625A: Global MASTER-Net observations report
- GRB 200625A: Fermi GBM Final Real-time Localization
- Updated catalog of X-ray bursts of SGR J1935+2154 from Insight-HXMT observations
- GRB 200623A: MMT observations at XRT Source #3
- GRB 200623A: Swift/UVOT Upper Limits
- IPN triangulation of GRB 200623B (short)
- GRB 200623A: Swift-XRT observations
- GRB 200623A: OAJ deep multi-color imaging, XRT #2 is pre-detected
- GRB 200623A: TNG optical observations
- GRB 200623A: AbAO afterglow candidate within XRT #2
- GRB 200623A: Fermi GBM observation
- Fermi GRB 200623B: Global MASTER-Net observations report
- GRB 200623B: Fermi GBM Final Real-time Localization
- GRB 200623A: Correction to GCN 28013
- GRB 200623A: Swift ToO observations
- IceCube-200620A: No significant detection in HAWC
- GRB 200623A: Swift/BAT-GUANO detection and arcminute localization of a short GRB
- Fermi GRB 200623A: Global MASTER-Net observations report
- GRB 200623A: Fermi GBM Final Real-time Localization
- IceCube-200620A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-200620A: INTEGRAL was inactive at the time of the event
- GRB 200622A: Fermi GBM Final Real-time Localization
- IceCube-200620A: MASTER previous detection of ZTF20abgvabi/AT2020ncr
- IceCube-200620A: not observable by Fermi-GBM
- IceCube-200620A: One Candidate Counterpart from the Zwicky Transient Facility
- Fermi-LAT Gamma-ray Observations of IceCube-200620A
- GRB 200613A: Continued CrAO optical observations
- IceCube-200620A: No ANTARES neutrino counterpart
- IceCube Alert 200620.13: Global MASTER-Net observations report
- GRB 200613A: CrAO optical observations
- GRB 200613A: R-band observations from HCT
- GRB 200613A: Further Liverpool Telescope observations
- IceCube-200620A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 200619C: Fermi GBM Final Real-time Localization
- Fermi GRB 200619B: Global MASTER-Net observations report
- GRB 200619B: AstroSat CZTI detection
- GRB 200619A: Fermi GBM observation
- Fermi trigger No 614239407: Global MASTER-Net observations report
- GRB 200619A: AGILE detection
- LIGO/Virgo MS200618aq: Retraction of a test binary neutron star candidate
- LIGO/Virgo MS200619bf: Retraction of a test binary neutron star candidate
- LIGO/Virgo MS200618bx: Retraction of a test binary neutron star candidate
- LIGO/Virgo MS200618bq: Retraction of a test binary neutron star candidate
- GRB 200619B: Fermi GBM Final Real-time Localization
- GRB 200619A: Insight-HXMT/HE detection
- Fermi trigger No 614226976: Global MASTER-Net observations report
- GRB 200613A: continued Kitab optical observations
- GRB 200613A: SAO RAS optical observations
- GRB 200617A: Insight-HXMT/HE detection
- IceCube-200530A - SN2020lls likely unrelated
- Swift/UVOT Observations of IceCube 200615A
- GRB 200613A: Mondy optical observations
- LIGO/Virgo MS200614ct: Identification of a test binary black hole candidate
- Fermi trigger No 614103490: Global MASTER-Net observations report
- Baksan Neutrino Observatory Alert 200617.47: Global MASTER-Net observations report
- GRB 200615B: CALET Gamma-Ray Burst Monitor detection
- Swift-XRT observations of IceCube 200615A
- IceCube-200615A: No significant detection in HAWC
- GRB 200613A: Jet-break from Xinglong-2.16m optical observations
- Fermi-LAT Gamma-ray Observations of IceCube-200615A
- IceCube-200614A: No significant detection in HAWC
- IceCube-200615A: Upper limits from a search for additional neutrino events in IceCube
- GRB 200616B: Fermi GBM Final Real-time Localization
- Fermi-LAT Gamma-ray Observations of IceCube-200614A and detection of a new gamma-ray source, Fermi J0202.8+3132
- LIGO/Virgo MS200615ce: Identification of a test binary black hole candidate
- GRB 200613A: CALET Gamma-Ray Burst Monitor detection
- LIGO/Virgo MS200614bz: Test Identification of a binary neutron star candidate
- GRB 200613A: MITSuME Akeno optical upper limits
- Fermi GRB 200616A: Global MASTER-Net observations report
- GRB 200615B: MAXI/GSC detection