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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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').
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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

3384 results found.

  1. EP251023a: GROWTH-India Telescope optical observations
  2. GRB 251023B: Glowbug gamma-ray detection
  3. EP251023a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm telescope at Teide Observatory
  4. EP251023a: Global MASTER-Net observations report
  5. GRB 251023B / EP#01709247298: COLIBRÍ optical counterpart candidate
  6. EP#01709247298: Swift-XRT counterpart detection
  7. EP251023a: Keck/LRIS spectroscopic redshift z=2.232
  8. EP251021b/GRB 251021A: SVOM/VT optical candidate
  9. EP251023a: NOT optical counterpart detection
  10. EP251023a: GSP Optical Counterpart Detection
  11. EP251023a: Einstein Probe detection of an X-ray transient
  12. EP/WXT 01709247295: GOTO optical afterglow candidate.
  13. GRB 251021A/EP251021b: Fermi-GBM Sub-Threshold Detection
  14. EP251021b: BOOTES-7 optical upper limit
  15. EP251021b: Einstein Probe detection of a fast X-ray transient
  16. Konus-Wind detection of GRB 251007A
  17. GRB 251013C: EP-FXT counterpart detection
  18. GRB 250919A: TERI gamma-ray detection
  19. EP251006a: Global MASTER-Net observations report
  20. GRB 251006B: Fermi GBM Observation
  21. GRB 251006B/EP251006a: EP-FXT afterglow detection
  22. GRB 251006B: Insight-HXMT detection
  23. EP251003a: LCO and VST fading optical counterpart
  24. GRB 251006B/EP251006a: SVOM/VT optical candidate
  25. GRB 251006B/EP251006a: EP-FXT follow-up observation
  26. GRB 251006B: COLIBRÍ optical upper limit
  27. GRB 251006B/EP251006a: EP-WXT detection
  28. EP251003a: Einstein Probe detection of an X-ray transient
  29. Fermi GBM Sub-Threshold Detection of GRB 250910A
  30. EP250821a: iTelescope T-59 possible detection of the optical counterpart
  31. GRB 251002A: Swift-XRT afterglow detection
  32. GRB 251002A: EP-FXT counterpart detection
  33. GRB 250925A/EP250925a: EP-WXT detection
  34. Konus-Wind detection of GRB 250920C
  35. EP250911a: e-MERLIN radio observations
  36. Konus-Wind detection of GRB 250920B
  37. Konus-Wind detection of GRB 250920A
  38. Konus-Wind detection of GRB 250911A
  39. GRB 250919A / EP250919a: LCO optical observation
  40. Konus-Wind detection of GRB 250919A
  41. GRB 250919A / EP250919a: Insight-HXMT detection
  42. GRB 250919A/EP250919a: SVOM/VT optical observation
  43. GRB 250919A / EP250919a: MASTER bright afterglow detection 24h after GRB time
  44. GRB 250919A: Fermi GBM Observation
  45. GRB 250919A / EP250919a: NuSTAR detection of bright prompt emission
  46. GRB 250919A: Swift-XRT afterglow detection
  47. GRB 250919A: Fermi-LAT detection
  48. EP250919a/GRB 250919A: Gemini/GMOS-S spectroscopic redshift z = 1.145
  49. EP250919a: Global MASTER-Net observations report
  50. EP250919a: Einstein Probe detection of an X-ray transient
  51. Correction for GCN 41877: EP-WXT ID is 01709243841
  52. The EP-WXT trigger 01709243841: Las Cumbres discovery of the optical counterpart
  53. EP250916a: EP-FXT follow-up observation
  54. The EP-WXT trigger 01709241037 is likely a flaring star
  55. EP250916a: Einstein Probe detection of an X-ray transient
  56. The EP-WXT trigger 01709240768 is likely a flaring star
  57. EP250911a: Global MASTER-Net observations report
  58. EP250908c: tentative VLT/FORS2 redshift z = 2.87
  59. EP250911a: Upper limit from Fermi-GBM Observations
  60. EP250911a: refined analysis of the EP-WXT and EP-FXT observations
  61. EP250911a: SVOM/VT optical observation
  62. EP250911a: Swift-XRT observations
  63. EP250911a: Optical detection with Kinder observations
  64. GRB 250910A / EP250910a: Swift-XRT afterglow detection
  65. GRB 250910A / EP250910a: SVOM/VT afterglow confirmation
  66. GRB 250910A / EP250910a : VLT/HAWK-I NIR counterpart discovery
  67. EP250911a: LCO optical counterpart discovery
  68. EP250910a: Global MASTER-Net observations report
  69. EP250911a: Einstein Probe detection of an X-ray transient
  70. GRB 250404A / EP250404a: spectroscopic redshift at z = 1.88 (correction to GCN 40084)
  71. GRB 250910A / EP250910a: VLT/HAWK-I near-infrared observations
  72. EP250910a/GRB 250910A: EP-WXT detection of a fast X-ray transient
  73. EP250908b/EP#01709240653: Swift/UVOT Detection
  74. EP#01709240653: Swift-XRT observations
  75. The EP-WXT trigger 01709240674 is triggered by the known source SS Cyg
  76. EP250908c: refined analysis of the EP-WXT and EP-FXT observations
  77. EP250908c: SVOM/VT optical observation
  78. EP250908c: VLT/FORS2 optical counterpart identification
  79. EP250908b: SVOM/VT optical candidate (Coordinate supplement for GCN 41758)
  80. EP250908b: SVOM/VT optical candidate
  81. The EP-WXT trigger EP250908a/01709240652 is not a real source
  82. EP250908c: Global MASTER-Net observations report
  83. EP250908c: Einstein Probe detection of an X-ray transient
  84. EP250908b: EP-WXT detection of a fast X-ray transient and EP-FXT observation
  85. EP#01709240652 (possibly EP250908a): FTW optical and NIR observations
  86. EP250905a: Liverpool Telescope i-band upper limits
  87. EP250905b: EP-FXT follow-up observation
  88. EP250905a: refined analysis of the EP-WXT and EP-FXT observations
  89. EP250905b: Global MASTER-Net observations report
  90. EP250905b: EP-WXT detection of a fast X-ray transient
  91. EP250905a: JinShan likely optical counterpart detection
  92. EP250905a: Global MASTER-Net observations report
  93. EP250905a: Einstein Probe detection of an X-ray transient
  94. EP detected a brightening of LMXB 1ES 1735-26.9
  95. EP250827a and EP250827b: Upper limit from Fermi-GBM Observations
  96. EP250903a: Swift-XRT observations
  97. EP#01709201209: Swift-XRT observations
  98. EP250903a: retraction of the LCO candidate, and discovery of the likely counterpart
  99. EP-WXT trigger 01709201209: Liverpool Telescope upper limits
  100. EP250903a: refined analysis of the EP-WXT and EP-FXT observations

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