Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! 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"

37139 results found.

  1. GRB 260225D: Glowbug gamma-ray detection of a likely short burst
  2. GRB 260226A: Glowbug gamma-ray detection
  3. GRB 260226A: NuSTAR detection of bright prompt emission
  4. GRB 260226A : GROWTH-India Telescope optical observations
  5. GRB 260226A: LAST optical upper limit
  6. GRB 260226A: Fermi GBM observation
  7. GRB 260226A: Fermi-LAT refined analysis
  8. Fermi GRB 260226A: Global MASTER-Net observations report
  9. GRB 260226A: AstroSat CZTI detection of bright long burst
  10. GRB 260226A: Fermi-LAT detection of a bright burst
  11. GRB 260226A???: BALROG localization (Fermi Trigger 793795080 / GRB 260226443)
  12. GRB260225A: SVOM/ECLAIRs refined position
  13. GRB 260226A: Fermi GBM Final Real-time Localization
  14. GRB 260225A: EP-FXT follow-up observation
  15. GRB 260225A: SVOM/VT optical observation
  16. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  17. GRB 260225C: Fermi GBM Final Real-time Localization
  18. GRB 260223A: Fermi GBM Observation
  19. GRB 260225A: SVOM/VT optical upper limits
  20. GRB 260225B: Fermi GBM Final Real-time Localization
  21. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  22. GRB 260225A: SVOM detection of a burst
  23. GRB 260223A: Glowbug gamma-ray detection
  24. EP260213a: Mephisto optical upper limits
  25. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  26. GRB 260223A: SVOM/VT optical observation
  27. GRB 260223A: SVOM/GRM observation
  28. GRB 260223A: COLIBRÍ further optical observations and a brightening
  29. EP260221a: Optical upper limit with Kinder observations
  30. GRB 260223A: COLIBRÍ optical observations
  31. GRB 260223A: DDOTI Optical Candidate
  32. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  33. Fermi GRB 260223A: Global MASTER-Net observations report
  34. GRB 260223A: Fermi GBM Final Real-time Localization
  35. EP260221a: COLIBRÍ optical counterpart candidate
  36. GRB 260222A: Fermi GBM Final Real-time Localization
  37. Fermi GRB 260221B: Global MASTER-Net observations report
  38. GRB 260221B: Fermi GBM Final Real-time Localization
  39. Fermi GRB 260221A: Global MASTER-Net observations report
  40. GRB 260221A: Fermi GBM Final Real-time Localization
  41. GRB 260219A: AstroSat CZTI detection
  42. GRB 260219A: GECAM-B observation of a long burst
  43. Fermi GRB 260219A: Global MASTER-Net observations report
  44. GRB 260219A: Fermi GBM Final Real-time Localization
  45. SVOM alert sb26021801: LAST optical upper limit
  46. GRB 260217A: Fermi GBM Final Localization
  47. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  48. EP260214b: Mondy optical observations
  49. EP260210a: Mondy optical upper limits
  50. Konus-Wind detection of GRB 260212A
  51. GRB 260208A: AbAO and Terskol optical upper limits
  52. GRB 260208A: continued Mondy optical observations
  53. IPN triangulation of GRB 260212A
  54. GRB 260213A: GECAM-B observation of a short burst
  55. GRB 260216A: Fermi Gamma-ray Burst Monitor trigger 792969362/260216886 is not a GRB
  56. GRB 260216A: Fermi GBM Final Real-time Localization
  57. EP260214b: Liverpool Telescope optical observations
  58. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  59. EP260214b: Optical upper limit with Kinder observations
  60. EP260214a: Optical upper limits with Kinder observations
  61. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  62. EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
  63. GRB 260211A: SVOM/VT optical counterpart
  64. GRB 260212A: AstroSat CZTI detection
  65. GRB 260212A: Fermi GBM Observation
  66. GRB 260212A: GECAM-B observation
  67. EP260213a: Optical upper limits with Kinder observations
  68. EP260213a: Mondy R-band optical upper limit
  69. GRB 260212A: SVOM/GRM observation of a long burst
  70. GRB 260213B: Fermi GBM Final Localization
  71. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  72. GRB 260211A - SVOM/ECLAIRs refined analysis
  73. GRB 260204A: SVOM/ECLAIRs refined analysis
  74. GRB 260213A: Fermi GBM Final Localization
  75. GRB 260211A: EP-FXT follow-up observation
  76. GRB 260211A: SVOM/VT optical observation
  77. GRB 260212A: Glowbug gamma-ray detection
  78. GRB 260211A: GOTO optical upper limit
  79. Fermi GRB 260212A: Global MASTER-Net observations report
  80. GRB 260212A: Fermi GBM Final Real-time Localization
  81. GRB 260211A: LAST optical upper limit
  82. GRB 260210A: SVOM/GRM observation
  83. Fermi GBM Sub-Threshold Detection of GRB 260211A
  84. Konus-Wind detection of GRB 260207B
  85. GRB 260128B: SVOM/ECLAIRs refined analysis
  86. GRID detection of GRB 260207B
  87. GRB 260211A: LCO optical upper limits
  88. GRB260131A/B: 3.6m DOT Optical Observations
  89. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  90. GRB 260211A: SVOM detection of a burst
  91. Konus-Wind detection of GRB 260209B
  92. GRB 260208A: Swift UVOT detection
  93. Konus-Wind detection of GRB 260127B
  94. Fermi GRB 260210C: Global MASTER-Net observations report
  95. GRB 260208A: LCO detection of the optical counterpart
  96. EP260209a: Einstein Probe detection of a fast X-ray transient
  97. EP260210a: Optical upper limits with Kinder observations
  98. IPN triangulation of GRB 260207B (short/hard with EE)
  99. GRB 260210C: Fermi GBM Final Real-time Localization
  100. GRB 260210A: Glowbug gamma-ray detection

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
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