Skip to main content
New! BOOM Notices and Schema v7.0.0. See news and announcements

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.

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').
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"
  1. EP260512a: Einstein Probe detection of an X-ray transient
  2. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  3. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  4. GRB 260512A: NuSTAR detection of prompt emission
  5. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  6. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  7. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  8. GRB 260512A: Fermi GBM Final Real-time Localization
  9. GRB 260511A: Glowbug gamma-ray detection
  10. Konus-Wind detection of GRB 260511A
  11. MASS-Cube (GRID 2.0) detection of GRB 260511A
  12. MASS-Cube (GRID 2.0) detection of GRB 260507A
  13. GRB 260511B: SAO RAS optical observations
  14. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  15. GRB 260511B: FRAM-ORM optical detection
  16. GRB 260511A: EP-FXT follow-up observation
  17. GRB 260511B: EP-FXT follow-up observation
  18. GRB 260511B: LCO optical counterpart detection
  19. GRB260511B: MAO/AZT-22 optical observations
  20. GRB 260511A: SVOM/VT optical observations
  21. GRB 260511B: LCO optical observations
  22. GRB 260511B: OHP/T193 spectroscopic observations
  23. GRB 260511B: GOTO optical counterpart detection
  24. GRB 260511B: Xinglong 2.16m/BEFOSC redshift confirmation
  25. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  26. GRB 260510A: AstroSat CZTI detection (Erroneous Submission)
  27. GRB 260511B: SVOM/VT optical observations
  28. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  29. GRB 260510B: EP-FXT follow-up observation
  30. GRB 260511B: OSIRIS+/GTC redshift z=2.006
  31. GRB 260510C: Fermi GBM Observation
  32. GRB 260509A: SAO RAS optical observations
  33. GRB 260511A: REM near-infrared detection
  34. GRB 260511B: GROWTH-India Telescope optical observations
  35. GRB 260511B: AstroSat CZTI detection
  36. GRB 260506B: Glowbug gamma-ray detection
  37. GRB 260506A: Glowbug gamma-ray detection of a short burst
  38. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  39. GRB 260511B: NuSTAR detection of prompt emission
  40. GRB 260511A: NuSTAR detection of prompt emission
  41. GRB 260511B: Fermi GBM Detection
  42. GRB 260511C: Fermi GBM Final Real-time Localization
  43. GRB 260511B: SVOM/VT optical observation with VHF data
  44. GRB 260511B: TRT optical observation
  45. GRB 260510B: SVOM/ECLAIRs refined analysis
  46. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  47. GRB 260511A: Fermi GBM Detection
  48. GRB 260511B SVOM/C-GFT optical counterpart detection
  49. EP260509a: LCO optical upper limits
  50. GRB 260511A: UTGO H50 optical afterglow observation
  51. GRB 260510C: AstroSat CZTI detection
  52. GRB 260511B: SVOM detection of a burst
  53. GRB 260511B: Fermi GBM Final Real-time Localization
  54. GRB 260510C: EP-FXT follow-up observation
  55. GRB 260510C: SVOM/VT optical counterpart confirmation
  56. EP260509a: EP-FXT non-detection and upper limit
  57. GRB 260511A: SVOM/VT optical observation with VHF data
  58. Fermi GRB 260511A: Global MASTER-Net observations report
  59. GRB 260511A: KAIT optical afterglow observations
  60. GRB 260511A: LCO optical afterglow detection
  61. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
  62. GRB 260511A: TRT optical counterpart detection
  63. GRB 260511A: SVOM detection of a bright burst
  64. GRB 260511A: BALROG localization (Fermi Trigger 800172815 / GRB 260511259)
  65. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  66. GRB 260511A: Fermi GBM Final Real-time Localization
  67. GRB 260510B: SVOM/VT optical upper limits
  68. GRB 260510C: SVOM/VT optical upper limits
  69. GRB 260510C: MAXI/GSC detection
  70. EP260509a: Global MASTER-Net observations report
  71. Fermi GBM Sub-Threshold Detection of GRB 260510B
  72. GRB 260510D: Fermi GBM Final Real-time Localization
  73. GRB 260510B: GOTO early upper limit
  74. GRB 260510C: SVOM detection of a burst
  75. GRB 260510C: Fermi GBM Final Real-time Localization
  76. GRB 260510A: GECAM-B observation
  77. GRB 260510B: LCO optical upper limits
  78. EP260509a: Einstein Probe detection of an X-ray transient
  79. GRB 260509A: Liverpool Telescope optical observations
  80. GRB 260510B: SVOM detection of a burst
  81. GRB 260509A: NOT spectroscopic redshift upper limit z < 1.95
  82. GRB 260509A: LCO optical observations
  83. SVOM GRB 260509A: MASTER-OAFA optical observation
  84. Fermi GRB 260510A: Global MASTER-Net observations report
  85. GRB 260509A: KAIT optical observations
  86. GRB 260509A: SVOM/COLIBRÍ (FM-GFT) observations
  87. GRB 260510A: Fermi GBM Final Real-time Localization
  88. GRB 260509A: SVOM/VT optical candidate with VHF data
  89. GRB 260509A: LCO optical counterpart detection
  90. GRB 260509A: GOTO optical counterpart candidate
  91. GRB 260509A: SVOM detection of a burst
  92. GRB 260506B: AstroSat CZTI detection
  93. IceCube-260504A: Upper limits from a search for additional neutrino events in IceCube
  94. EP260507a: REM optical/NIR observations
  95. EP260507a: refined analysis of the EP-WXT and EP-FXT observations
  96. GRB 260507B / EP260507a: Fermi-GBM Sub-Threshold Detection
  97. EP260507a: COLIBRÍ optical observations
  98. EP260507a: SVOM/VT optical observations
  99. EP260507a: NOT optical observations
  100. EP260507a: further Liverpool Telescope observations

Advanced

Download all Circulars as a .tar.gz archive:
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov