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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"

1103 results found.

  1. EP#01709320865: Swift-XRT observations
  2. EP261003a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  3. Trigger_21915: Swift ToO observations
  4. EP261003a: Einstein Probe detection of an X-ray transient
  5. Fermi GBM Detection of GRB 260919A / EP260920a
  6. The EP-WXT trigger 01709320790 is likely a flaring star
  7. EP260927a: Einstein Probe detection of a fast X-ray transient
  8. The EP-WXT trigger 01709320726 is likely a flaring star
  9. EP260924a: EP-FXT follow-up observation
  10. EP260924a: EP-WXT detection of an X-ray transient
  11. The EP-WXT trigger 01709319842 is likely a flaring star
  12. Trigger_21914: Swift ToO observations
  13. The EP-WXT trigger 01709319528 is likely a flaring star
  14. EP260920b: refined analysis of the EP-WXT and EP-FXT observations
  15. The EP-WXT trigger 01709318601 is likely a flaring star
  16. EP260920b: Einstein Probe detection of an X-ray transient
  17. EP-WXT detected a brightening of HMXB LS V +44 17
  18. EP260920a: NOT optical upper limits
  19. EP260920a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  20. EP260917b: EP-FXT non-detection and upper limit
  21. EP260920a: LCO optical counterpart candidate
  22. EP260920a: Einstein Probe detection of an X-ray transient
  23. EP260917a: refined analysis of the EP-FXT observations
  24. The EP-WXT trigger 01709318491 is likely a flaring star
  25. EP260806a: Yamaguchi Interferometer radio detections
  26. The EP-WXT trigger 01709318279 is likely a flaring star
  27. GRB 260918A: EP-FXT follow-up observation
  28. EP260917b: EP-WXT detection of an X-ray transient
  29. GRB 260917B: EP-FXT follow-up observation
  30. EP260917a: Einstein Probe detection of an X-ray transient
  31. The EP-WXT trigger 01709317235 is likely a flaring star
  32. GRB 260915A: EP-FXT follow-up observation
  33. GRB 260914A: EP-FXT follow-up observation
  34. EP260806a: VLA+ALMA radio detections
  35. GRB 260909A: EP-FXT follow-up observation
  36. EP260806a: NOEMA detection
  37. The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
  38. The EP-WXT trigger 01709305715 is likely a flaring star
  39. EP260903a: EP-FXT follow-up observation
  40. The EP-WXT trigger 01709302592 is likely a flaring star
  41. EP260903a: EP-WXT detection of a fast X-ray transient
  42. GRB 260903A: EP-FXT follow-up observation
  43. EP260901a: EP-FXT follow-up observation
  44. EP260830a: EP-FXT follow-up observation
  45. EP260901a: EP-WXT detection of a fast X-ray transient
  46. GRB 260831B: EP-FXT follow-up observation
  47. EP260830a: EP-WXT detection of a fast X-ray transient
  48. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
  49. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  50. GRB 260822A: SVOM/VT optical upper limits
  51. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  52. GRB 260822A: EP/FXT follow-up observations
  53. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  54. EP260822a: EP-FXT non-detection and upper limit
  55. EP260822a: Einstein Probe detection of a fast X-ray transient
  56. The EP-WXT trigger 01709287395 is likely a flaring star
  57. The EP-WXT trigger 01709286204 is likely a flaring star
  58. EP detected a brightening of LMXB 1ES 1735-26.9
  59. GRB 260818B: EP-FXT follow-up observation
  60. GRB260818A: EP-FXT follow-up observation
  61. EP260812a: AbAO optical upper limit
  62. The EP-WXT trigger 01709281429 is likely a flaring star
  63. EP260812a: AZT-22 optical upper limit
  64. EP260806a: WFST optical observations
  65. The EP-WXT trigger 01709280562 is likely a flaring star
  66. EP260812b: Optical upper limit with Kinder
  67. The EP-WXT trigger 01709279838 is likely a flaring star
  68. EP260812a: NOT and Liverpool Telescope upper limits:
  69. EP260812b: Liverpool Telescope observations
  70. EP260812b: GOTO detection of the optical counterpart
  71. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  72. EP260812b: Einstein Probe detection of an X-ray transient
  73. EP260812a: Einstein Probe detection of an X-ray transient
  74. GRB260809A/EPF_J234751.2+210212: EP-FXT follow-up observation
  75. The EP-WXT trigger 01709278015 is likely a flaring star
  76. EP260809a:refined analysis of the EP-WXT and autonomous EP-FXT observation
  77. GRB 260808B / EPF_J230056.0+082842: EP-FXT follow-up observation
  78. EP260809a: Einstein Probe detection of an X-ray transient
  79. EP260806a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  80. EP260806a: Liverpool Telescope observations of the counterpart show a blue colour
  81. EP260731a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  82. EP260806a: Einstein Probe detection of an X-ray transient
  83. GRB 260802A / EP J223759.5+521421: EP-FXT follow-up observation
  84. The EP-WXT trigger 01709277420 is likely a flaring star
  85. EP260731a: Einstein Probe detection of an X-ray transient
  86. The EP-WXT trigger 01709277130 (EP260729a): refined EP-WXT analysis and association with a flaring star
  87. EP 260729a: Ondrejov D50 optical detection supports stellar flare origin
  88. EP260729a: Einstein Probe detection of an X-ray transient
  89. EP260728a: EP-FXT follow-up observation
  90. EP260728a: Einstein Probe detection of a fast X-ray transient
  91. EP260727a: 1.5m OSN optical counterpart detection
  92. EP260727a:refined analysis of the EP-WXT and EP-FXT observation
  93. EP260727a: Liverpool Telescope confirmation of optical counterpart
  94. EP260727a: Einstein Probe detection of an X-ray transient
  95. EP260723a: further EP-FXT follow-up observation
  96. EP260725a: EP-FXT follow-up observation and association with a bright flaring star
  97. EP260725a: EP-WXT detection of an X-ray transient
  98. EP260723a: Continued Liverpool Telescope observations suggest hours long optical plateau or rebrightening
  99. EP260723a: EP-FXT follow-up observation
  100. EP260723a: Liverpool Telescope likely optical counterpart

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