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"

27451 results found.

  1. EP260527a: COLIBRÍ optical detection
  2. EP260527a: Einstein Probe detection of a fast X-ray transient
  3. The EP-WXT trigger 01709266172 is likely a flaring star
  4. The EP-WXT trigger 01709266147 is likely a flaring star
  5. Fermi trigger No 801580882: Global MASTER-Net observations report
  6. GRB 260524A: SVOM/ECLAIRs detection of a burst through on-ground search
  7. EP260526a: Einstein Probe detection of a fast X-ray transient
  8. EP260526.405: COLIBRÍ optical upper limits
  9. The EP-WXT trigger 01709266106 is not a real source
  10. Fermi GRB 260526A: Global MASTER-Net observations report
  11. GRB 260526A: Fermi GBM Final Real-time Localization
  12. EP01709266106 (EP260526a?): Liverpool Telescope upper limits
  13. EP-WXT 01709266106: NOT optical upper limits
  14. Fermi GRB 260525A: Global MASTER-Net observations report
  15. GRB 260525A: Fermi GBM Final Real-time Localization
  16. Fermi GRB 260523A: Global MASTER-Net observations report
  17. GRB 260523B: Fermi GBM Final Real-time Localization
  18. GRB 260523A: Fermi GBM Final Real-time Localization
  19. GRB 260522A: Fermi GBM Observation
  20. EP260518a (AT2026ndp): LCO observations and Gemini-South Redshift z = 2.28
  21. GRB 260522B: Fermi GBM Final Real-time Localization
  22. GRB 260522A: GOTO optical upper limit
  23. Fermi trigger No 801135305: Global MASTER-Net observations report
  24. Fermi GRB 260522A: Global MASTER-Net observations report
  25. GRB 260522A: Fermi-LAT detection
  26. GRB 260519C: SVOM/GRM observation
  27. GRB 260522A: Fermi GBM Final Real-time Localization
  28. GRB 260511A: iTelescope T-75 optical detection
  29. GRB 260520B: Fermi GBM Final Localization
  30. GRB 260520A: Fermi GBM Final Localization
  31. GRB 260519D: Fermi GBM Final Localization Correction
  32. GRB 260519B: Fermi GBM Final Localization
  33. GRB 260519A: Fermi GBM Final Localization
  34. GRB 260516D: SVOM/ECLAIRs refined analysis
  35. GRB 260515A: SVOM/ECLAIRs refined analysis
  36. GRB 260509A: CrAO ZTSh optical upper limit
  37. GRB 260516D: EP-FXT follow-up observation
  38. GRB 260516D: LCO optical observations
  39. GRB 260515A: further Liverpool Telescope observations
  40. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  41. GRB 260516D: GTC/OSIRIS+ spectroscopic redshift z = 1.801
  42. GRB 260516D: GROWTH-India Telescope optical detection
  43. GRB 260516D: SVOM/VT optical bright candidate
  44. GRB 260516D: FRAM-ORM optical limit
  45. GRB 260515A: CrAO ZTSh BVRI optical observations
  46. Fermi GRB 260516C: Global MASTER-Net observations report
  47. SVOM GRB260516D: Global MASTER-Net observations report
  48. GRB 260516D: SVOM possible detection of a burst
  49. GRB 260516C: Fermi GBM Final Real-time Localization
  50. GRB 260515A: LCO optical counterpart detection
  51. Fermi Gamma-ray Burst Monitor trigger 800627191/260516518 is not a GRB
  52. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  53. GRB 260515A: EP-FXT follow-up observation
  54. EP260514a: NOT optical counterpart confirmation
  55. EP260514a: TRT optical counterpart candidate
  56. EP260514a: SVOM/VT optical candidate
  57. Fermi GRB 260516B: Global MASTER-Net observations report
  58. GRB 260516B: Fermi GBM Final Real-time Localization
  59. Fermi Gamma-ray Burst Monitor trigger 800592653/260516119 is not a GRB
  60. GRB 260515A: SVOM/VT optical observations
  61. GRB 260515A: OHP/T193 optical observations
  62. EP260514a: COLIBRÍ optical upper limits
  63. GRB 260516A: Fermi GBM Final Real-time Localization
  64. GRB 260515A: GTC/OSIRIS+ spectroscopic redshift z = 0.764
  65. GRB 260515A: LCO optical observations
  66. SVOM GRB 260515A: Global MASTER-Net observations report
  67. GRB 260515A: NOT optical observations.
  68. GRB 260515A: SVOM/VT optical candidate from VHF data
  69. GRB 260515A: JinShan optical counterpart candidate
  70. GRB 260515A: SVOM detection of a burst
  71. EP260514a: GROWTH-India Telescope optical upper limit
  72. GRB 260511B: NOT optical observations
  73. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  74. GRB 260511B: GMG Optical Upper Limit
  75. EP260514a: Global MASTER-Net observations report
  76. IPN triangulation of GRB 260512A
  77. GRB 260511B: Mephisto multi-band optical followup
  78. Fermi GRB 260514A: Global MASTER-Net observations report
  79. The EP-WXT trigger 01709262077 is likely a flaring star
  80. EP260507a: Xinglong Schmidt optical counterpart detection
  81. GRB 260514A: Fermi GBM Final Real-time Localization
  82. EP260512a: Global MASTER-Net observations report
  83. Fermi GRB 260513A: Global MASTER-Net observations report
  84. Fermi GRB 260512A: Global MASTER-Net observations report
  85. GRB 260513A: Fermi GBM Final Real-time Localization
  86. GRB 260509A: SVOM/VT optical observations
  87. The EP-WXT trigger 01709262036 is likely a flaring star
  88. EP260512a: COLIBRÍ optical upper limits
  89. EP260512a: Einstein Probe detection of an X-ray transient
  90. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  91. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  92. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  93. GRB 260512A: Fermi GBM Final Real-time Localization
  94. GRB 260511B: SAO RAS optical observations
  95. GRB 260511A: EP-FXT follow-up observation
  96. GRB 260511B: EP-FXT follow-up observation
  97. GRB 260511B: LCO optical counterpart detection
  98. GRB260511B: MAO/AZT-22 optical observations
  99. GRB 260511A: SVOM/VT optical observations
  100. GRB 260511B: LCO optical 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