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"

28259 results found.

  1. EP260227a: Einstein Probe detection of an X-ray transient and refined analysis
  2. The EP-WXT trigger 01709258681 (EP260227a?): Las Cumbres follow-up observation of the optical counterpart
  3. EP/WXT trigger 01709258681 (EP260227a?): LCO candidate afterglow
  4. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  5. EP260214a: VLT/FORS2 optical observations
  6. GRB 260225A: WINTER J-band upper limit
  7. GRB 260226A: COLIBRÍ optical upper limits
  8. GRB 260226A: LCOGT Optical Upper Limit
  9. EP-WXT trigger 01709258652: SVOM/C-GFT confirmation of a stellar flare
  10. GRB 260225D: Glowbug gamma-ray detection of a likely short burst
  11. GRB 260226A: Glowbug gamma-ray detection
  12. GRB 260226A: NuSTAR detection of bright prompt emission
  13. GRB 260226A : GROWTH-India Telescope optical observations
  14. GRB 260226A: LAST optical upper limit
  15. GRB 260226A: Fermi GBM observation
  16. LAT GRB260226.44: Global MASTER-Net observations report
  17. Fermi GRB 260226A: Global MASTER-Net observations report
  18. GRB 260226A: AstroSat CZTI detection of bright long burst
  19. GRB 260226A???: BALROG localization (Fermi Trigger 793795080 / GRB 260226443)
  20. EP260224a: LCO optical upper limits
  21. GRB 260225A: EP-FXT follow-up observation
  22. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  23. GRB 260223A: Fermi GBM Observation
  24. GRB 260225A: SVOM/VT optical upper limits
  25. EP260223a: Liverpool Telescope upper limits
  26. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  27. EP260224a: Einstein Probe detection of an X-ray transient
  28. EP 260225.148: COLIBRÍ Confirmation of flaring star
  29. EP260223a: Xinglong optical upper limit
  30. GRB 260223A: Glowbug gamma-ray detection
  31. EP260213a: Mephisto optical upper limits
  32. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  33. sb26021801: SVOM/C-GFT upper limit
  34. EP260223a: COLIBRÍ optical upper limits
  35. EP260223a: Einstein Probe detection of an X-ray transient
  36. GRB 260223A: SVOM/GRM observation
  37. GRB 260223A: COLIBRÍ further optical observations and a brightening
  38. EP260221a: Optical upper limit with Kinder observations
  39. GRB 260223A: COLIBRÍ optical observations
  40. GRB 260223A: DDOTI Optical Candidate
  41. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  42. Fermi GRB 260223A: Global MASTER-Net observations report
  43. EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
  44. EP260221a: COLIBRÍ optical counterpart candidate
  45. EP260221a: Gemini South z-band upper limit
  46. EP260221a: Global MASTER-Net observations report
  47. EP260221a: EP-FXT follow-up observation
  48. Fermi GRB 260221B: Global MASTER-Net observations report
  49. EP-WXT01709258519: Xinglong optical upper limit
  50. EP260221a: Xinglong optical upper limit
  51. Fermi GRB 260221A: Global MASTER-Net observations report
  52. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  53. EP260221a: GOTO optical upper limit
  54. EP260221a: COLIBRÍ optical upper limit
  55. SVOM alert sb26021801: LCO optical upper limit
  56. EP260221a: Einstein Probe detection of an X-ray transient
  57. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  58. Fermi GRB 260219A: Global MASTER-Net observations report
  59. SVOM alert sb26021801: LAST optical upper limit
  60. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  61. IceCube Alert 260217A: Global MASTER-Net observations report
  62. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  63. sb26021801: SVOM detection of a long faint X-ray transient
  64. EP-WXT 01709258455: NOT optical upper limits
  65. EP260214b: Mondy optical observations
  66. EP260214b: 1.3m DFOT optical upper limit
  67. EP260210a: Mondy optical upper limits
  68. GRB 260208A: AbAO and Terskol optical upper limits
  69. GRB 260208A: continued Mondy optical observations
  70. IPN triangulation of GRB 260212A
  71. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  72. EP260214b: Liverpool Telescope optical observations
  73. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  74. EP260214b: Optical upper limit with Kinder observations
  75. EP260214a: Optical upper limits with Kinder observations
  76. EP260214b: EP-FXT follow-up observation
  77. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  78. EP260214b: DDOTI Optical Detection
  79. EP260214b: GROWTH-India Telescope optical upper limit
  80. EP260214a: VLT near-infrared observation
  81. EP260214a: NOT optical upper limits
  82. EP260214a: COLIBRÍ optical upper limits
  83. EP260214b: OHP/T120 optical observations
  84. EP260214a: refined analysis of the EP-FXT observation
  85. EP260214b: LCO optical counterpart detection
  86. GRB 260211A: SVOM/VT optical counterpart
  87. EP260214b: COLIBRÍ optical observations
  88. EP260214b: NOT optical counterpart detection
  89. EP260214b: Einstein Probe detection of a fast X-ray transient
  90. EP260214a: Global MASTER-Net observations report
  91. EP260214a: Einstein Probe detection of an X-ray transient
  92. GRB 260212A: AstroSat CZTI detection
  93. GRB 260212A: Fermi GBM Observation
  94. EP260213a: Liverpool Telescope optical upper limits
  95. EP260213a: Global MASTER-Net observations report
  96. EP260213a: COLIBRÍ optical upper limits
  97. EP260213a: Optical upper limits with Kinder observations
  98. EP260213a: Mondy R-band optical upper limit
  99. EP260213a: SVOM/C-GFT upper limit
  100. EP260213a: refined analysis of the EP-FXT observation

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