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"

41697 results found.

  1. EP260214a: VLT/FORS2 optical observations
  2. GRB 260225A: WINTER J-band upper limit
  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/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  25. GRB 260225C: Fermi GBM Final Real-time Localization
  26. GRB 260223A: Fermi GBM Observation
  27. GRB 260225A: SVOM/VT optical upper limits
  28. GRB 260225B: Fermi GBM Final Real-time Localization
  29. EP260126a: VLA 6 GHz detection
  30. EP260223a: Liverpool Telescope upper limits
  31. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  32. GRB 260225A: SVOM detection of a burst
  33. EP260224a: Einstein Probe detection of an X-ray transient
  34. EP 260225.148: COLIBRÍ Confirmation of flaring star
  35. EP260223a: Xinglong optical upper limit
  36. The EP-WXT trigger 01709258631 is likely a flaring star
  37. GRB 260223A: Glowbug gamma-ray detection
  38. EP260213a: Mephisto optical upper limits
  39. EP260223a: EP-FXT follow-up observation
  40. sb26021801: SVOM/VT optical upper limits
  41. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  42. sb26021801: SVOM/C-GFT upper limit
  43. EP260223a: COLIBRÍ optical upper limits
  44. EP260223a: Einstein Probe detection of an X-ray transient
  45. GRB 260223A: SVOM/VT optical observation
  46. GRB 260223A: SVOM/GRM observation
  47. GRB 260223A: COLIBRÍ further optical observations and a brightening
  48. EP260221a: Optical upper limit with Kinder observations
  49. GRB 260223A: COLIBRÍ optical observations
  50. GRB 260223A: DDOTI Optical Candidate
  51. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  52. Fermi GRB 260223A: Global MASTER-Net observations report
  53. GRB 260223A: Fermi GBM Final Real-time Localization
  54. EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
  55. EP260221a: COLIBRÍ optical counterpart candidate
  56. EP260221a: Gemini South z-band upper limit
  57. GRB 260222A: Fermi GBM Final Real-time Localization
  58. EP260221a: Global MASTER-Net observations report
  59. EP260221a: EP-FXT follow-up observation
  60. Fermi GRB 260221B: Global MASTER-Net observations report
  61. GRB 260221B: Fermi GBM Final Real-time Localization
  62. EP-WXT01709258519: Xinglong optical upper limit
  63. EP260221a: Xinglong optical upper limit
  64. Fermi GRB 260221A: Global MASTER-Net observations report
  65. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  66. GRB 260221A: Fermi GBM Final Real-time Localization
  67. EP260221a: GOTO optical upper limit
  68. EP260221a: COLIBRÍ optical upper limit
  69. SVOM alert sb26021801: LCO optical upper limit
  70. EP260221a: Einstein Probe detection of an X-ray transient
  71. The EP-WXT trigger 01709258519 is likely caused by Mrk 421
  72. GRB 260219A: AstroSat CZTI detection
  73. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  74. GRB 260219A: GECAM-B observation of a long burst
  75. Fermi GRB 260219A: Global MASTER-Net observations report
  76. GRB 260219A: Fermi GBM Final Real-time Localization
  77. SVOM alert sb26021801: LAST optical upper limit
  78. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  79. IceCube Alert 260217A: Global MASTER-Net observations report
  80. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  81. GRB 260217A: Fermi GBM Final Localization
  82. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  83. sb26021801: SVOM detection of a long faint X-ray transient
  84. The EP-WXT trigger 01709258455 is likely a flaring star
  85. EP-WXT 01709258455: NOT optical upper limits
  86. EP260214b: Mondy optical observations
  87. EP260214b: 1.3m DFOT optical upper limit
  88. EP260210a: Mondy optical upper limits
  89. Konus-Wind detection of GRB 260212A
  90. GRB 260208A: AbAO and Terskol optical upper limits
  91. GRB 260208A: continued Mondy optical observations
  92. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  93. GRB 260213A: GECAM-B observation of a short burst
  94. GRB 260216A: Fermi GBM Final Real-time Localization
  95. EP260214b: Liverpool Telescope optical observations
  96. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  97. EP260214b: Optical upper limit with Kinder observations
  98. EP260214a: Optical upper limits with Kinder observations
  99. EP260214b: EP-FXT follow-up observation
  100. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold 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