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"

3319 results found.

  1. EP260119a: SVOM/VT optical observation
  2. EP260119a: update of EP-FXT follow-up observation
  3. EP260119a: NOT optical observations
  4. EP260116a: COLIBRÍ detection of a fading optical source
  5. EP260119a: Global MASTER-Net observations report
  6. EP260119a: COLIBRÍ optical counterpart candidate
  7. EP260119a: preliminary result from the EP-FXT observation
  8. EP260119a: EP-WXT detection of a fast X-ray transient
  9. GRB 260117A: SVOM/VT optical candidate
  10. GRB 260117A: SVOM/C-GFT upper limit
  11. EP 260116a: COLIBRÍ optical upper limit
  12. EP260116a: Liverpool Telescope upper limits
  13. EP260116A: 1.3m DFOT optical upper limit
  14. EP260116a: Global MASTER-Net observations report
  15. EP260116a: Xinglong optical upper limit
  16. EP260116a: Einstein Probe detection of an X-ray transient
  17. Konus-Wind detection of GRB 260114A
  18. Konus-Wind detection of GRB 251230A / EP251230a
  19. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  20. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  21. EP260110a: TRT optical upper limits
  22. Konus-Wind detection of GRB 260101A
  23. The EP-WXT trigger 01709251266 is likely a flaring star
  24. EP260110a: SVOM/VT optical upper limits
  25. EP260110a: Global MASTER-Net observations report
  26. EP260110a: KAIT optical upper limit
  27. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  28. EP 260110a: COLIBRÍ optical observations
  29. EP260110a: SVOM/C-GFT upper limit
  30. EP260110a: BOOTES-5/JGU optical upper limit
  31. EP260110a: Einstein Probe detection of an X-ray transient
  32. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  33. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  34. The EP-WXT trigger 01709251112 is likely a flaring star
  35. EP260105a: FTW optical observations
  36. The EP-WXT trigger 01709251028 is likely a flaring star
  37. EP260105a: SVOM/VT optical upperlimit
  38. EP260105a: refined analysis of the EP-WXT and EP-FXT observations
  39. EP260105a: LCO Optical Upper limit
  40. EP260104a: Global MASTER-Net observations report
  41. EP260104a: Einstein Probe detection of a fast X-ray transient
  42. EP260105a: Global MASTER-Net observations report
  43. EP260105a: Einstein Probe detection of an X-ray transient
  44. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  45. GRB 260102A: EP-FXT follow-up observation
  46. EP260101a: Global MASTER-Net observations report
  47. GRB 251230A / EP251230a: GECAM-B detection
  48. GRB 251230A / EP251230a: Insight-HXMT/HE detection
  49. EP260101a: refined analysis of the EP-WXT and EP-FXT observations
  50. EP260101a: Einstein Probe detection of an X-ray transient
  51. GRB 251230A / EP251230a: SVOM/VT optical continued observations and upper limit
  52. EP251229a: Optical upper limit with Kinder observations
  53. EP251230a / GRB 251230A: refined analysis of the EP-WXT and EP-FXT observations
  54. EP251229a: BOOTES-2 early optical upper limit
  55. EP251229a: NOT optical upper limits
  56. GRB 251230A / EP251230a: SVOM/VT optical observation
  57. EP251229a: refined analysis of the EP-WXT and EP-FXT observations
  58. EP-WXT trigger 01709250662 Mephisto and 50cm telescope follow-up
  59. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  60. GRB 251230A/EP#01709250693 (likely EP251230a): FTW optical and NIR observations
  61. The EP-WXT trigger 01709250693/GRB 251230A: Las Cumbres detection of the optical counterpart
  62. EP251229a: Global MASTER-Net observations report
  63. EP251229a: Einstein Probe detection of an X-ray transient
  64. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  65. The EP-WXT trigger 01709250662 is likely a flaring star
  66. The EP-WXT trigger 01709250617 is likely a flaring star
  67. EP251222a: Optical upper limit with Kinder observations
  68. EP251220a: 3.6m DOT optical afterglow detection
  69. GRB 251222A: Fermi GBM Observation
  70. EP251220a: CrAO ZTSh optical observations
  71. EP251221a: PRIME upper limit
  72. EP251222a: Global MASTER-Net observations report
  73. EP251221a: Liverpool Telescope upper limits
  74. EP251222a: refined analysis of the EP-WXT and EP-FXT observations
  75. EP251222b/GRB 251222A: refined analysis of the EP-WXT and EP-FXT observations
  76. Konus-Wind detection of GRB 251222A / EP251222b
  77. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  78. EP251222a: NTT/ULTRACAM optical observations
  79. EP251222a: GOTO optical upper limit
  80. GRB 251222A / EP251222b: GOTO optical counterpart detection
  81. EP251222a: GSP Optical Counterpart Detection
  82. GRB 251222A / EP251222b: VLT/X-shooter spectroscopic redshift z = 3.171
  83. EP251222b/GRB 251222A: SVOM/GRM observation
  84. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  85. EP251222a: Einstein Probe detection of an X-ray transient
  86. The EP-WXT trigger 01709250397 is likely a flaring star
  87. EP251221a: Global MASTER-Net observations report
  88. EP251221a: NOT optical upper limit
  89. EP251220a: VLT/FORS2 spectroscopic redshift z = 2.375
  90. EP251220a: NOT optical observations
  91. EP251221a: Einstein Probe detection of a fast X-ray transient
  92. EP251220a: EP-FXT follow-up observation
  93. EP 251220a: GOTO optical counterpart detection
  94. EP 251220a: COLIBRÍ detection of the optical counterpart
  95. EP251220a: Global MASTER-Net observations report
  96. EP251220a: EP detection of a fast X-ray transient
  97. EP251214b: KAIT optical upper limit
  98. EP251214a: Optical upper limit with Kinder observations
  99. EP251214b: Global MASTER-Net observations report
  100. EP251214b : Einstein Probe detection of a fast X-ray transient

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Looking for U.S. government information and services? Visit USA.gov