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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"

3295 results found.

  1. IPN triangulation of GRB 240802A / EP 240802a
  2. EP240801a: Osservatorio Astronomico Nastro Verde upper limit
  3. EP240802A: Bassano Bresciano Observatory upper limit
  4. EP240802a: Time coincidence with GRB 240802A and optical upper limits with Kinder observations
  5. EP240802a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  6. EP240801a: optical observations at CrAO and AbAO
  7. EP240801a: GRANDMA and Kilonova-Catcher optical observations
  8. EP240801a: Leavitt Observatory optical observations
  9. EP240801a: GTC spectroscopy and absorption redshift
  10. EP240801a: JinShan optical observations
  11. EP240801a: NOT optical observations
  12. EP240801a: follow-up observation with LCOGT
  13. EP240801a: Kinder follow-up observations of the candidate counterpart
  14. EP240801a: TRT optical counterpart detection
  15. EP240801a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  16. EP-WXT trigger 01709002661 is not a real source
  17. Konus-Wind detection of GRB 240718A
  18. IceCube-Cascade 240714A: TRT optical observations on the EP/FXT positions
  19. IceCube-Cascade 240714A: X-ray follow-up observation with EP-FXT
  20. GRB 240713A: 2.2m CAHA optical limit
  21. EP240708a: X-ray follow-up observations with Swift/XRT
  22. Konus-Wind detection of GRB 240715A
  23. GRB 240713A: Swift-XRT observations
  24. GRB 240713A: optical upper limits from the INAF Asiago Observatory
  25. EP-WXT flaring star and the optical flaring activity during its decay phase
  26. JinShan confirmation of the EP-WXT source triggered on July 14th due to a flaring star
  27. The EP-WXT source triggered on July 14th is likely a flaring star
  28. GRB 240713A: J-band upper limit from WINTER
  29. GRB 240713A: NOT optical upper limits on three EP/FXT candidates
  30. GRB 240713A: JinShan optical upper limits
  31. GRB 240713A: OHP/T120 optical upper limit
  32. GRB240713A: X-ray follow-up observation with EP-FXT (duplicate submission of GCN 36859)
  33. GRB240713A: X-ray follow-up observation with EP-FXT
  34. EP240708a: GSP optical upper limit
  35. EP240708a: KAIT optical upper limit
  36. EP240708a: NOT optical observations
  37. EP240708a: SVOM/C-GFT optical upper limit
  38. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  39. EP240708a: Optical upper limits with Kinder observations
  40. EP240708a: EP-WXT detection of a fast X-ray transient
  41. EP240703b: GSP optical upper limit
  42. EP240703b: TRT optical upper limits
  43. EP240703a: TRT further optical observation
  44. EP240702a: TRT optical upper limits
  45. Konus-Wind detection of GRB 240627A
  46. EP240703a and EP240703b: Swift/XRT upper limits
  47. EP240703a: KAIT optical upper limit
  48. EP240703c: Kinder optical follow-up and Swift XRT observations
  49. EP240703a: BOOTES-3 optical upper limit
  50. EP240703a: Kinder optical follow-up observations
  51. EP240703c: EP-WXT detection of an X-ray transient
  52. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  53. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  54. EP240703b: EP-WXT detection of a fast X-ray transient
  55. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  56. EP240702a: Swift/XRT upper limit
  57. EP240703a: EP-WXT detection of a fast X-ray transient
  58. EP240702a: GSP optical upper limit
  59. EP240702a: EP-WXT detection of a fast X-ray transient
  60. EP240626a: Montarrenti Observatory optical upper limit
  61. EP240626a: KAIT optical upper limit
  62. EP240625a: GRANDMA Optical Upper Limits
  63. EP240626a: EP-FXT detection of the X-ray emission
  64. Konus-Wind detection of GRB 240619A
  65. EP240626a: BOOTES-7 optical upper limit
  66. EP240626a: EP-WXT detection of a fast X-ray transient
  67. EP240625a: NOT optical counterpart candidate
  68. EP240625a: EP-FXT detection of the X-ray emission
  69. EP240625a: EP-WXT detection of a fast X-ray transient
  70. EP240618a: NOT further optical observations
  71. EP240618a: NOT optical counterpart candidate
  72. EP240618a: GSP optical upper limit
  73. X-ray transient EP240618a: Fermi/GBM non-detection
  74. EP240618a: Swift/XRT upper limit
  75. EP240617a: tentative Swift/XRT detection of the afterglow
  76. EP240618a: GRANDMA Optical Upper Limits
  77. EP240618a: TRT optical upper limit
  78. EP240618a: BOOTES-6/DPRT optical upper limit
  79. EP240617a: BOOTES-6/DPRT optical upper limit
  80. EP240617a: EP-WXT detection of a fast X-ray transient
  81. EP240618a: EP-WXT detection of a fast X-ray transient and EP-FXT quick follow-up
  82. X-ray transient EP240414a: Chandra late time observation
  83. Konus-Wind detection of GRB 240615A (short/hard)
  84. Konus-Wind detection of GRB 240607A
  85. Konus-Wind detection of GRB 240606B
  86. Konus-Wind detection of GRB 240603A
  87. The EP-WXT source triggered on June 1st is likely a flaring star
  88. Konus-Wind detection of GRB 240529A
  89. LXT 240528A: LEIA detection of a fast X-ray transient
  90. EP240518a: GSP optical upper limit
  91. EP240518a: possibly identified with a flare star by EP-FXT
  92. EP240518a: EP-WXT detection of a new X-ray transient
  93. Konus-Wind detection of GRB 240513A
  94. EP240506a: Xinglong optical upper limit
  95. EP240506a: CrAO ZTSH optical upper limit
  96. EP240506a: Archival radio searching
  97. EP240506a: TRT optical upper limit
  98. EP240506a: BOOTES Network optical upper limit
  99. EP240506a: Optical upper limit with Kinder observations
  100. EP240506a: EP-WXT detection of a new fast X-ray transient

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