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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"

3311 results found.

  1. Konus-Wind detection of GRB 240802A (EP240802a)
  2. Improved IPN triangulation of GRB 240802A / EP 240802a
  3. Konus-Wind detection of GRB 240805A
  4. Konus-Wind detection of GRB 240804B (a counterpart of EP240804a)
  5. EP240806a: EP-FXT detection of the X-ray emission
  6. EP 240806A: LCO optical observations
  7. EP240806a: GSP optical counterpart detection
  8. EP240806a: EP-WXT detection of a fast X-ray transient
  9. EP240804a: BOOTES-6/DPRT optical detection
  10. EP240804a: VLT/X-shooter spectroscopic redshift
  11. EP240804a: LCOGT optical counterpart detection
  12. EP-WXT trigger 00109017646 is not a real source
  13. EP240804a: NOT optical counterpart detection
  14. EP240804a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  15. EP240802a: correction of EP-WXT trigger time in GCN 37019
  16. EP240802a: Montarrenti Observatory optical upper limit
  17. IPN triangulation of GRB 240802A / EP 240802a
  18. EP240801a: Osservatorio Astronomico Nastro Verde upper limit
  19. EP240802A: Bassano Bresciano Observatory upper limit
  20. EP240802a: Time coincidence with GRB 240802A and optical upper limits with Kinder observations
  21. EP240802a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  22. EP240801a: optical observations at CrAO and AbAO
  23. EP240801a: GRANDMA and Kilonova-Catcher optical observations
  24. EP240801a: Leavitt Observatory optical observations
  25. EP240801a: GTC spectroscopy and absorption redshift
  26. EP240801a: JinShan optical observations
  27. EP240801a: NOT optical observations
  28. EP240801a: follow-up observation with LCOGT
  29. EP240801a: Kinder follow-up observations of the candidate counterpart
  30. EP240801a: TRT optical counterpart detection
  31. EP240801a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  32. EP-WXT trigger 01709002661 is not a real source
  33. Konus-Wind detection of GRB 240718A
  34. IceCube-Cascade 240714A: TRT optical observations on the EP/FXT positions
  35. IceCube-Cascade 240714A: X-ray follow-up observation with EP-FXT
  36. GRB 240713A: 2.2m CAHA optical limit
  37. EP240708a: X-ray follow-up observations with Swift/XRT
  38. Konus-Wind detection of GRB 240715A
  39. GRB 240713A: Swift-XRT observations
  40. GRB 240713A: optical upper limits from the INAF Asiago Observatory
  41. EP-WXT flaring star and the optical flaring activity during its decay phase
  42. JinShan confirmation of the EP-WXT source triggered on July 14th due to a flaring star
  43. The EP-WXT source triggered on July 14th is likely a flaring star
  44. GRB 240713A: J-band upper limit from WINTER
  45. GRB 240713A: NOT optical upper limits on three EP/FXT candidates
  46. GRB 240713A: JinShan optical upper limits
  47. GRB 240713A: OHP/T120 optical upper limit
  48. GRB240713A: X-ray follow-up observation with EP-FXT (duplicate submission of GCN 36859)
  49. GRB240713A: X-ray follow-up observation with EP-FXT
  50. EP240708a: GSP optical upper limit
  51. EP240708a: KAIT optical upper limit
  52. EP240708a: NOT optical observations
  53. EP240708a: SVOM/C-GFT optical upper limit
  54. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  55. EP240708a: Optical upper limits with Kinder observations
  56. EP240708a: EP-WXT detection of a fast X-ray transient
  57. EP240703b: GSP optical upper limit
  58. EP240703b: TRT optical upper limits
  59. EP240703a: TRT further optical observation
  60. EP240702a: TRT optical upper limits
  61. Konus-Wind detection of GRB 240627A
  62. EP240703a and EP240703b: Swift/XRT upper limits
  63. EP240703a: KAIT optical upper limit
  64. EP240703c: Kinder optical follow-up and Swift XRT observations
  65. EP240703a: BOOTES-3 optical upper limit
  66. EP240703a: Kinder optical follow-up observations
  67. EP240703c: EP-WXT detection of an X-ray transient
  68. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  69. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  70. EP240703b: EP-WXT detection of a fast X-ray transient
  71. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  72. EP240702a: Swift/XRT upper limit
  73. EP240703a: EP-WXT detection of a fast X-ray transient
  74. EP240702a: GSP optical upper limit
  75. EP240702a: EP-WXT detection of a fast X-ray transient
  76. EP240626a: Montarrenti Observatory optical upper limit
  77. EP240626a: KAIT optical upper limit
  78. EP240625a: GRANDMA Optical Upper Limits
  79. EP240626a: EP-FXT detection of the X-ray emission
  80. Konus-Wind detection of GRB 240619A
  81. EP240626a: BOOTES-7 optical upper limit
  82. EP240626a: EP-WXT detection of a fast X-ray transient
  83. EP240625a: NOT optical counterpart candidate
  84. EP240625a: EP-FXT detection of the X-ray emission
  85. EP240625a: EP-WXT detection of a fast X-ray transient
  86. EP240618a: NOT further optical observations
  87. EP240618a: NOT optical counterpart candidate
  88. EP240618a: GSP optical upper limit
  89. X-ray transient EP240618a: Fermi/GBM non-detection
  90. EP240618a: Swift/XRT upper limit
  91. EP240617a: tentative Swift/XRT detection of the afterglow
  92. EP240618a: GRANDMA Optical Upper Limits
  93. EP240618a: TRT optical upper limit
  94. EP240618a: BOOTES-6/DPRT optical upper limit
  95. EP240617a: BOOTES-6/DPRT optical upper limit
  96. EP240617a: EP-WXT detection of a fast X-ray transient
  97. EP240618a: EP-WXT detection of a fast X-ray transient and EP-FXT quick follow-up
  98. X-ray transient EP240414a: Chandra late time observation
  99. Konus-Wind detection of GRB 240615A (short/hard)
  100. Konus-Wind detection of GRB 240607A

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