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"- LXT 240402A/GRB 240402B: Glowbug gamma-ray detection
- X-ray transient LXT 240402A: WFST optical upper limits
- Konus-Wind detection of LXT 240402A/GRB 240402B
- GRB/FXT 240402B: Kinder optical counterpart candidate
- IceCube-240327B: GRANDMA observations of 4FGL J0555.9+0030
- GRB/FXT 240402B: VLT/FORS2 optical afterglow candidate
- GRB 240403A: Fermi GBM Detection
- X-ray transient LXT240402A: AST3-3 optical upper limits
- LXT 240402A: EP-FXT detection of the X-ray afterglow
- Fermi GRB 240404A: Global MASTER-Net observations report
- GRB 240404A: Fermi GBM Final Real-time Localization
- LXT 240402A: MASTER optical observations with AGN in error-box
- GRB 240402B: GWAC-F50A optical upper limit
- GRB 240402B: GECAM-C detection
- X-ray transient LXT 240402A: LEIA detection
- GRB 240403A: BALROG localization (Fermi Trigger 733838255 / GRB 240403498)
- Fermi trigger No 733808041: Global MASTER-Net observations report
- Fermi GRB 240402A: Global MASTER-Net observations report
- GRB 240402A: Fermi GBM Final Real-time Localization
- X-ray transient EP240331a: Kinder optical upper limits
- X-ray transient EP240331A: GRANDMA-Kilonova catcher optical upper limit
- EP240331A: MASTER optical observations
- Transient EP240315a: J-band observations of AT2024eju with WIRC
- X-ray transient EP20240331a: MeerLICHT optical upper limits
- IBAS Alert n.10651 not a GRB
- IceCube-240327B: Upper limits from a search for additional neutrino events in IceCube
- IceCube-240327A: Upper limits from a search for additional neutrino events in IceCube
- Integral GRB240401.69: Global MASTER-Net observations report
- GRB 240329A: Glowbug gamma-ray detection
- GRB 240324A: AstroSat CZTI detection of a short burst
- GRB 240331A: AstroSat CZTI detection
- GRB 240329A: AstroSat CZTI detection
- GRB 240331A: Fermi GBM Final Real-time Localization
- GRB 240329A: GRBAlpha detection
- Fermi trigger No 733366352: Global MASTER-Net observations report
- Fermi GRB 240329A: Global MASTER-Net observations report
- GRB 240329A: BALROG localization (Fermi Trigger 733441392 / GRB 240329905)
- GRB 240329A: Fermi GBM Final Real-time Localization
- Fermi GRB 240328B: Global MASTER-Net observations report
- Fermi GRB 240328A: Global MASTER-Net observations report
- X-ray transient EP240315a: continued ATCA monitoring
- IceCube-240327B: No candidates from the Zwicky Transient Facility
- GRB 240328C: Glowbug gamma-ray detection
- GRB 240328B: Fermi GBM Final Real-time Localization
- GRB 240328A: Fermi GBM Final Real-time Localization
- IceCube Alert 240327.68: Global MASTER-Net observations report
- IceCube-240327B - IceCube observation of a high-energy neutrino candidate track-like event
- IceCube-240327A - IceCube observation of a high-energy neutrino candidate track-like event
- X-ray transient EP 240315a: Second epoch Chandra observations
- Fermi trigger No 733097506: Global MASTER-Net observations report
- X-ray transient EP240315a: e-MERLIN radio observations
- X-ray transient EP240315a: Ondrejov D50 optical limit
- Transient EPW20240219aa: REM optical/NIR further observations
- Fermi trigger No 733092476: Global MASTER-Net observations report
- GRB 240320A: Glowbug gamma-ray detection
- Fermi trigger No 732937833: Global MASTER-Net observations report
- GRB 240318A: Fermi GBM Observation
- Fermi GRB 240320A: Global MASTER-Net observations report
- Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
- GRB 240315C / X-ray transient EP240315a: Swift/BAT detection
- Fermi trigger No 732657380: Global MASTER-Net observations report
- GRB 240318A: Swift/BAT-GUANO detection of a burst outside the coded FOV
- X-ray transient EP240315a: ATCA detection of radio counterpart
- GRB 240320A: Fermi GBM Final Real-time Localization
- IPN triangulation of GRB 240315C (consistent with a fast X-ray transient EP240315a)
- GRB 240317B: Swift/BAT-GUANO Angular Error Correction
- Fermi Gamma-ray Burst Monitor trigger 732299243/240316686 is not a GRB
- X-ray transient EP 240315a: Chandra observations
- X-ray transient EP240315a: GTC/HiPERCAM photometry
- X-ray transient EP240315a: MeerKAT radio detection
- X-ray transient EP240315a: GTC/OSIRIS spectroscopic redshift confirmation
- GRB 240318A: Glowbug gamma-ray detection
- GRB 240317C: Glowbug gamma-ray detection
- GRB 240318B: Glowbug gamma-ray detection
- X-ray transient EP240315a: PRIME near infrared detection
- GRB 240317B: Fermi GBM Observation
- X-ray transient EP240315a: 3.6 m TNG NIR detection
- Swift satellite in safe mode
- X-ray transient EP240315a/AT2024eju: TShAO (Zeiss-1000) observatory optical upper limit
- X-ray transient EP240315a: EP-FXT detection of the X-ray afterglow
- Fermi GRB 240318A: Global MASTER-Net observations report
- GRB 240318A: Fermi GBM Final Real-time Localization
- GRB 240317B: Swift/BAT-GUANO arcminute localization of a burst
- GRB 240317A: AstroSat CZTI detection
- GRB 240315B: AstroSat CZTI detection
- X-ray transient EP240315a: Kitab observatory optical upper limitns
- X-ray transient EP240315a: Montarrenti Observatory optical upper limit
- Fermi GRB 240317B: Global MASTER-Net observations report
- Fermi GRB 240317A: Global MASTER-Net observations report
- GRB 240317B: Fermi GBM Final Real-time Localization
- X-ray transient EP240315a: orphan FXT?
- GRB 240317A: Fermi GBM Final Real-time Localization
- X-ray transient EP240315a: Kinder follow-up observations for AT 2024eju with Lulin observatory
- X-ray transient EP240315a: GROND J-band detection
- X-ray transient EP240315a: VLT/X-shooter spectroscopic redshift of z = 4.859
- X-ray transient EP240315a: Nanshan/HMT optical upper limit
- Fermi trigger No 732299243: Global MASTER-Net observations report
- AT2024eju: followup observations with Liverpool Telescope suggest a fading transient
- X-ray transient EP240315a: ATLAS detection of a possible optical counterpart AT2024eju
- Einstein Probe detected of a fast X-ray transient EP240315a