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"22076 results found.
- Fermi-LAT gamma-ray observations of IceCube-240327B
- Fermi-LAT gamma-ray observations of IceCube-240327A
- Fermi GRB 240405B: Global MASTER-Net observations report
- LXT 240402A/GRB 240402B: GECAM-C refined analysis
- Swift satellite resumes pointed science observations
- X-ray transient LXT 240402A: WFST optical upper limits
- IceCube-240327B: GRANDMA observations of 4FGL J0555.9+0030
- GRB/FXT 240402B: VLT/FORS2 optical afterglow candidate
- LXT 240402A: EP-FXT detection of the X-ray afterglow
- Fermi GRB 240404A: Global MASTER-Net observations report
- LXT 240402A: MASTER optical observations with AGN in error-box
- X-ray transient LXT 240402A: LEIA detection
- Fermi trigger No 733808041: Global MASTER-Net observations report
- Fermi GRB 240402A: Global MASTER-Net observations report
- 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
- Integral GRB240401.69: Global MASTER-Net observations report
- Fermi trigger No 733366352: Global MASTER-Net observations report
- Fermi GRB 240329A: Global MASTER-Net observations report
- 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
- IceCube Alert 240327.68: Global MASTER-Net observations report
- 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
- Fermi trigger No 732937833: Global MASTER-Net observations report
- Fermi GRB 240320A: Global MASTER-Net observations report
- Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
- 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
- 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
- X-ray transient EP240315a: PRIME near infrared detection
- X-ray transient EP240315a: 3.6 m TNG NIR detection
- Swift satellite in safe mode
- X-ray transient EP240315a: EP-FXT detection of the X-ray afterglow
- Fermi GRB 240318A: Global MASTER-Net observations report
- GRB 240317B: Swift/BAT-GUANO arcminute localization of a burst
- 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
- X-ray transient EP240315a: Kinder follow-up observations for AT 2024eju with Lulin observatory
- 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
- Fermi GRB 240314A: Global MASTER-Net observations report
- GRB 240310A: MASTER OT J200702.72-263928.7 inside 3sigma
- Fermi trigger No 731839490: Global MASTER-Net observations report
- Fermi-LAT gamma-ray observations of IceCube-240307A
- Fermi GRB 240310A: Global MASTER-Net observations report
- Swift GRB240309.61: Global MASTER-Net observations report
- Fermi trigger No 731571927: Global MASTER-Net observations report
- GRB 231215A: further radio observations with the VLA
- IceCube Alert 240307.32: Global MASTER-Net observations report
- Fermi GRB 240306A: Global MASTER-Net observations report
- Fermi GRB 240305A: Global MASTER-Net observations report
- GRB 240306A: Swift/BAT-GUANO detection of a burst
- Fermi-LAT gamma-ray observations of IceCube-240229A
- Swift GRB240305.18: Global MASTER-Net observations report
- Swift GRB240305.16: Global MASTER-Net observations report
- Fermi GRB 240305C: Global MASTER-Net observations report
- GRB 240305A: Swift/BAT-GUANO arcminute localization of a burst
- GRB 240218A: ALMA detection
- GRB 240218A: Chandra Detection and Jet Break Confirmation
- Fermi trigger No 731303574: Global MASTER-Net observations report
- Konus-Wind detection of GRB 240227A (short/hard)
- GRB240218A: ATCA observation of the radio counterpart
- Transient EPW20240219aa: Optical observations with LDT
- GRB 240225B: Swift-XRT afterglow detection
- Fermi trigger No 731161136: Global MASTER-Net observations report
- Swift GRB 240303A: Global MASTER-Net observations report
- Swift J151857.0-572147: Confirmation of a new galactic transient
- GRB 240215A: Swift-XRT afterglow detection
- GRB 240218A: NOEMA upper limit
- GRB 240225B: further SAO RAS optical observations
- Fermi GRB 240229A: Global MASTER-Net observations report
- IceCube Alert 240229.66: Global MASTER-Net observations report
- GRB 240225B: Swift ToO observations
- Konus-Wind detection of GRB 240225B (long)
- GRB 240225B: 3.6m DOT observation
- GRB 240225B: WINTER near-IR observations and upper limits
- GRB 240225B: SAO RAS optical observations
- GRB 240225B: Mondy afterglow observations
- Fermi GRB 240227A: Global MASTER-Net observations report
- GRB 240225B: Liverpool Telescope afterglow observations
- GRB 240225B: Liverpool Telescope optical afterglow observations