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"

45716 results found.

  1. GRB 260225A: WINTER J-band upper limit
  2. GRB 260226A: CALET Gamma-Ray Burst Monitor detection
  3. GRB 260226A: COLIBRÍ optical upper limits
  4. GRB 260226A: LCOGT Optical Upper Limit
  5. EP-WXT trigger 01709258652: SVOM/C-GFT confirmation of a stellar flare
  6. GRB 260225D: Glowbug gamma-ray detection of a likely short burst
  7. GRB 260226A: Glowbug gamma-ray detection
  8. GRB 260226A: NuSTAR detection of bright prompt emission
  9. GRB 260226A : GROWTH-India Telescope optical observations
  10. GRB 260226A: LAST optical upper limit
  11. GRB 260226A: Fermi GBM observation
  12. GRB 260226A: Fermi-LAT refined analysis
  13. The EP-WXT trigger 01709258652 is likely a flaring star
  14. LAT GRB260226.44: Global MASTER-Net observations report
  15. Fermi GRB 260226A: Global MASTER-Net observations report
  16. GRB 260226A: AstroSat CZTI detection of bright long burst
  17. EP260214a: VLA 6 GHz detection
  18. GRB 260226A: Fermi-LAT detection of a bright burst
  19. GRB 260226A???: BALROG localization (Fermi Trigger 793795080 / GRB 260226443)
  20. EP260224a: LCO optical upper limits
  21. GRB260225A: SVOM/ECLAIRs refined position
  22. GRB 260226A: Fermi GBM Final Real-time Localization
  23. GRB 260225A: EP-FXT follow-up observation
  24. GRB 260225A: SVOM/VT optical observation
  25. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  26. GRB 260225C: Fermi GBM Final Real-time Localization
  27. GRB 260223A: Fermi GBM Observation
  28. GRB 260225A: SVOM/VT optical upper limits
  29. GRB 260225B: Fermi GBM Final Real-time Localization
  30. EP260126a: VLA 6 GHz detection
  31. EP260223a: Liverpool Telescope upper limits
  32. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  33. GRB 260225A: SVOM detection of a burst
  34. EP260224a: Einstein Probe detection of an X-ray transient
  35. EP 260225.148: COLIBRÍ Confirmation of flaring star
  36. EP260223a: Xinglong optical upper limit
  37. The EP-WXT trigger 01709258631 is likely a flaring star
  38. GRB 260223A: Glowbug gamma-ray detection
  39. EP260213a: Mephisto optical upper limits
  40. EP260223a: EP-FXT follow-up observation
  41. sb26021801: SVOM/VT optical upper limits
  42. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  43. sb26021801: SVOM/C-GFT upper limit
  44. EP260223a: COLIBRÍ optical upper limits
  45. EP260223a: Einstein Probe detection of an X-ray transient
  46. GRB 260223A: SVOM/VT optical observation
  47. GRB 260223A: SVOM/GRM observation
  48. GRB 260223A: COLIBRÍ further optical observations and a brightening
  49. EP260221a: Optical upper limit with Kinder observations
  50. GRB 260223A: COLIBRÍ optical observations
  51. GRB 260223A: DDOTI Optical Candidate
  52. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  53. Fermi GRB 260223A: Global MASTER-Net observations report
  54. GRB 260223A: Fermi GBM Final Real-time Localization
  55. EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
  56. EP260221a: COLIBRÍ optical counterpart candidate
  57. EP260221a: Gemini South z-band upper limit
  58. GRB 260222A: Fermi GBM Final Real-time Localization
  59. EP260221a: Global MASTER-Net observations report
  60. EP260221a: EP-FXT follow-up observation
  61. Fermi GRB 260221B: Global MASTER-Net observations report
  62. GRB 260221B: Fermi GBM Final Real-time Localization
  63. EP-WXT01709258519: Xinglong optical upper limit
  64. EP260221a: Xinglong optical upper limit
  65. Fermi GRB 260221A: Global MASTER-Net observations report
  66. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  67. GRB 260221A: Fermi GBM Final Real-time Localization
  68. EP260221a: GOTO optical upper limit
  69. EP260221a: COLIBRÍ optical upper limit
  70. SVOM alert sb26021801: LCO optical upper limit
  71. EP260221a: Einstein Probe detection of an X-ray transient
  72. The EP-WXT trigger 01709258519 is likely caused by Mrk 421
  73. GRB 260219A: AstroSat CZTI detection
  74. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  75. GRB 260219A: GECAM-B observation of a long burst
  76. Fermi GRB 260219A: Global MASTER-Net observations report
  77. GRB 260219A: Fermi GBM Final Real-time Localization
  78. SVOM alert sb26021801: LAST optical upper limit
  79. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  80. IceCube Alert 260217A: Global MASTER-Net observations report
  81. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  82. GRB 260217A: Fermi GBM Final Localization
  83. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  84. sb26021801: SVOM detection of a long faint X-ray transient
  85. The EP-WXT trigger 01709258455 is likely a flaring star
  86. EP-WXT 01709258455: NOT optical upper limits
  87. EP260214b: Mondy optical observations
  88. EP260214b: 1.3m DFOT optical upper limit
  89. EP260210a: Mondy optical upper limits
  90. Konus-Wind detection of GRB 260212A
  91. GRB 260208A: AbAO and Terskol optical upper limits
  92. GRB 260208A: continued Mondy optical observations
  93. IPN triangulation of GRB 260212A
  94. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  95. GRB 260213A: GECAM-B observation of a short burst
  96. GRB 260216A: Fermi Gamma-ray Burst Monitor trigger 792969362/260216886 is not a GRB
  97. GRB 260216A: Fermi GBM Final Real-time Localization
  98. EP260214b: Liverpool Telescope optical observations
  99. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  100. EP260214b: Optical upper limit with Kinder observations

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