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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"

1070 results found.

  1. EP260806a: VLA+ALMA radio detections
  2. GRB 260909A: EP-FXT follow-up observation
  3. EP260806a: NOEMA detection
  4. The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
  5. The EP-WXT trigger 01709305715 is likely a flaring star
  6. EP260903a: EP-FXT follow-up observation
  7. The EP-WXT trigger 01709302592 is likely a flaring star
  8. EP260903a: EP-WXT detection of a fast X-ray transient
  9. GRB 260903A: EP-FXT follow-up observation
  10. EP260901a: EP-FXT follow-up observation
  11. EP260830a: EP-FXT follow-up observation
  12. EP260901a: EP-WXT detection of a fast X-ray transient
  13. GRB 260831B: EP-FXT follow-up observation
  14. EP260830a: EP-WXT detection of a fast X-ray transient
  15. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
  16. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  17. GRB 260822A: SVOM/VT optical upper limits
  18. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  19. GRB 260822A: EP/FXT follow-up observations
  20. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  21. EP260822a: EP-FXT non-detection and upper limit
  22. EP260822a: Einstein Probe detection of a fast X-ray transient
  23. The EP-WXT trigger 01709287395 is likely a flaring star
  24. The EP-WXT trigger 01709286204 is likely a flaring star
  25. EP detected a brightening of LMXB 1ES 1735-26.9
  26. GRB 260818B: EP-FXT follow-up observation
  27. GRB260818A: EP-FXT follow-up observation
  28. EP260812a: AbAO optical upper limit
  29. The EP-WXT trigger 01709281429 is likely a flaring star
  30. EP260812a: AZT-22 optical upper limit
  31. EP260806a: WFST optical observations
  32. The EP-WXT trigger 01709280562 is likely a flaring star
  33. EP260812b: Optical upper limit with Kinder
  34. The EP-WXT trigger 01709279838 is likely a flaring star
  35. EP260812a: NOT and Liverpool Telescope upper limits:
  36. EP260812b: Liverpool Telescope observations
  37. EP260812b: GOTO detection of the optical counterpart
  38. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  39. EP260812b: Einstein Probe detection of an X-ray transient
  40. EP260812a: Einstein Probe detection of an X-ray transient
  41. GRB260809A/EPF_J234751.2+210212: EP-FXT follow-up observation
  42. The EP-WXT trigger 01709278015 is likely a flaring star
  43. EP260809a:refined analysis of the EP-WXT and autonomous EP-FXT observation
  44. GRB 260808B / EPF_J230056.0+082842: EP-FXT follow-up observation
  45. EP260809a: Einstein Probe detection of an X-ray transient
  46. EP260806a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  47. EP260806a: Liverpool Telescope observations of the counterpart show a blue colour
  48. EP260731a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  49. EP260806a: Einstein Probe detection of an X-ray transient
  50. GRB 260802A / EP J223759.5+521421: EP-FXT follow-up observation
  51. The EP-WXT trigger 01709277420 is likely a flaring star
  52. EP260731a: Einstein Probe detection of an X-ray transient
  53. The EP-WXT trigger 01709277130 (EP260729a): refined EP-WXT analysis and association with a flaring star
  54. EP 260729a: Ondrejov D50 optical detection supports stellar flare origin
  55. EP260729a: Einstein Probe detection of an X-ray transient
  56. EP260728a: EP-FXT follow-up observation
  57. EP260728a: Einstein Probe detection of a fast X-ray transient
  58. EP260727a: 1.5m OSN optical counterpart detection
  59. EP260727a:refined analysis of the EP-WXT and EP-FXT observation
  60. EP260727a: Liverpool Telescope confirmation of optical counterpart
  61. EP260727a: Einstein Probe detection of an X-ray transient
  62. EP260723a: further EP-FXT follow-up observation
  63. EP260725a: EP-FXT follow-up observation and association with a bright flaring star
  64. EP260725a: EP-WXT detection of an X-ray transient
  65. EP260723a: Continued Liverpool Telescope observations suggest hours long optical plateau or rebrightening
  66. EP260723a: EP-FXT follow-up observation
  67. EP260723a: Liverpool Telescope likely optical counterpart
  68. EP260723a: EP-WXT detection of a fast X-ray transient
  69. GRB 260718A: EP-FXT follow-up observation
  70. EP260713a: Einstein Probe detection of an X-ray transient
  71. EP260711a: EP-FXT follow-up observation
  72. EP260711a: Einstein Probe detection of an X-ray transient
  73. The EP-WXT trigger 01709274666 is likely a new outburst of the CV SS Cyg
  74. EP260707a is not a real source
  75. EP260707a: Einstein Probe detection of an X-ray transient
  76. GRB 260706A: EP-FXT follow-up observation
  77. The EP-WXT trigger 01709274151 is likely a flaring star
  78. The EP-WXT trigger 01709274141 is likely a flaring star
  79. The EP-WXT trigger 01709274014 is likely a flaring star
  80. GRB 260704A: EP-FXT follow-up observation
  81. EP260703a: EP-FXT follow-up observation
  82. EP260703a: EP-WXT detection of a fast X-ray transient
  83. EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
  84. EP260628a: EP-FXT follow-up observation
  85. EP260628a: EP-WXT detection of a fast X-ray transient
  86. The EP-WXT trigger 01709272671 is likely a flaring star
  87. EP260626a: EP-FXT follow-up observation
  88. EP260626a: Liverpool Telescope upper limits
  89. EP260626a: EP-WXT detection of a fast X-ray transient
  90. EP260623a:refined analysis of the EP-WXT and EP-FXT observation
  91. EP260623a: Optical follow-up observations with Kinder
  92. EP260623a: SVOM/VT optical observations
  93. EP260623a: Las Cumbres discovery of the optical counterpart
  94. EP260623a: Einstein Probe detection of an X-ray transient
  95. The EP-WXT trigger 01709271197 is likely a flaring star
  96. EP260618a: EP-FXT follow-up observation
  97. EP260618a: EP-WXT detection of an X-ray transient
  98. EP260616a/GRB 260616B: EP-FXT follow-up observation
  99. GRB 260616B: CALET Gamma-Ray Burst Monitor detection
  100. EP260616a: EP-WXT detection of a fast X-ray transient

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