Skip to main content
JSON Notices via Email, Kafka Cron Jobs, Submitter Profile, GCN is Hiring. See news and announcements

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').
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"

28108 results found.

  1. Fermi GRB 260221A: Global MASTER-Net observations report
  2. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  3. EP260221a: GOTO optical upper limit
  4. EP260221a: COLIBRÍ optical upper limit
  5. SVOM alert sb26021801: LCO optical upper limit
  6. EP260221a: Einstein Probe detection of an X-ray transient
  7. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  8. Fermi GRB 260219A: Global MASTER-Net observations report
  9. SVOM alert sb26021801: LAST optical upper limit
  10. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  11. IceCube Alert 260217A: Global MASTER-Net observations report
  12. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  13. sb26021801: SVOM detection of a long faint X-ray transient
  14. EP-WXT 01709258455: NOT optical upper limits
  15. EP260214b: Mondy optical observations
  16. EP260214b: 1.3m DFOT optical upper limit
  17. EP260210a: Mondy optical upper limits
  18. GRB 260208A: AbAO and Terskol optical upper limits
  19. GRB 260208A: continued Mondy optical observations
  20. IPN triangulation of GRB 260212A
  21. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  22. EP260214b: Liverpool Telescope optical observations
  23. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  24. EP260214b: Optical upper limit with Kinder observations
  25. EP260214a: Optical upper limits with Kinder observations
  26. EP260214b: EP-FXT follow-up observation
  27. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  28. EP260214b: DDOTI Optical Detection
  29. EP260214b: GROWTH-India Telescope optical upper limit
  30. EP260214a: VLT near-infrared observation
  31. EP260214a: NOT optical upper limits
  32. EP260214a: COLIBRÍ optical upper limits
  33. EP260214b: OHP/T120 optical observations
  34. EP260214a: refined analysis of the EP-FXT observation
  35. EP260214b: LCO optical counterpart detection
  36. GRB 260211A: SVOM/VT optical counterpart
  37. EP260214b: COLIBRÍ optical observations
  38. EP260214b: NOT optical counterpart detection
  39. EP260214b: Einstein Probe detection of a fast X-ray transient
  40. EP260214a: Global MASTER-Net observations report
  41. EP260214a: Einstein Probe detection of an X-ray transient
  42. GRB 260212A: AstroSat CZTI detection
  43. GRB 260212A: Fermi GBM Observation
  44. EP260213a: Liverpool Telescope optical upper limits
  45. EP260213a: Global MASTER-Net observations report
  46. EP260213a: COLIBRÍ optical upper limits
  47. EP260213a: Optical upper limits with Kinder observations
  48. EP260213a: Mondy R-band optical upper limit
  49. EP260213a: SVOM/C-GFT upper limit
  50. EP260213a: refined analysis of the EP-FXT observation
  51. EP260213a: Einstein Probe detection of a fast X-ray transient
  52. EP/WXT 01709258378: NOT optical upper limits
  53. GRB 260212A: SVOM/GRM observation of a long burst
  54. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  55. GRB 260211A: EP-FXT follow-up observation
  56. GRB 260211A: SVOM/VT optical observation
  57. GRB 260212A: Glowbug gamma-ray detection
  58. Fermi GRB 260212A: Global MASTER-Net observations report
  59. GRB 260211A: LAST optical upper limit
  60. GRB 260210A: SVOM/GRM observation
  61. Fermi GBM Sub-Threshold Detection of GRB 260211A
  62. GRID detection of GRB 260207B
  63. GRB 260211A: LCO optical upper limits
  64. GRB260131A/B: 3.6m DOT Optical Observations
  65. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  66. Fermi trigger No 792537871: Global MASTER-Net observations report
  67. Swift Operations Update + Community Forum (Friday, February 13 @ 10:00 AM EST)
  68. EP260209a: COLIBRÍ optical upper limit
  69. Fermi GRB 260210C: Global MASTER-Net observations report
  70. EP260209a: LCO optical upper limits
  71. EP260210a: Global MASTER-Net observations report
  72. EP260210a: refined analysis of the EP-FXT observation
  73. EP260209a: Global MASTER-Net observations report
  74. GRB 260208A: LCO detection of the optical counterpart
  75. EP260209a: Einstein Probe detection of a fast X-ray transient
  76. EP260210a: Optical upper limits with Kinder observations
  77. GRB 260210A: Glowbug gamma-ray detection
  78. GRB 260208C: AstroSat CZTI detection
  79. EP260210a: COLIBRÍ optical upper limit
  80. EP260210a: SVOM/C-GFT upper limit
  81. EP260210a: Einstein Probe detection of an X-ray transient
  82. GRB 260207B: AstroSat CZTI detection
  83. GRB 260208C: SVOM/GRM observation
  84. GRB 260204A: Swift-XRT afterglow detection
  85. GRB 260208B: AstroSat CZTI detection of a bright long burst
  86. GRB260208A: Liverpool Telescope optical follow-up observations
  87. GRB 260208A: Glowbug gamma-ray detection
  88. GRB 260208A: NuSTAR detection of prompt emission
  89. GRB 260208A: Fermi GBM Observation
  90. Fermi GRB 260209A: Global MASTER-Net observations report
  91. GRB 260208B: Swift-XRT observations
  92. GRB 260131A/B: continued Mondy optical observations
  93. GRB 260204A: Swift/UVOT Upper Limits
  94. GRB 260208B: COLIBRÍ optical observations
  95. GRB 260208A: Mondy optical observations
  96. GRB 260208A: 1.3m DFOT optical detection
  97. GRB 260208A: COLIBRÍ optical observations
  98. GRB 260208B: EP-FXT observation
  99. Fermi GRB 260208C: Global MASTER-Net observations report
  100. GRB 260208B: SVOM/VT optical candidate

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