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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').
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.

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

3377 results found.

  1. EP251021b/GRB 251021A: SVOM/VT optical candidate
  2. EP251023a: NOT optical counterpart detection
  3. EP251023a: GSP Optical Counterpart Detection
  4. EP251023a: Einstein Probe detection of an X-ray transient
  5. EP/WXT 01709247295: GOTO optical afterglow candidate.
  6. GRB 251021A/EP251021b: Fermi-GBM Sub-Threshold Detection
  7. EP251021b: BOOTES-7 optical upper limit
  8. EP251021b: Einstein Probe detection of a fast X-ray transient
  9. Konus-Wind detection of GRB 251007A
  10. GRB 251013C: EP-FXT counterpart detection
  11. GRB 250919A: TERI gamma-ray detection
  12. EP251006a: Global MASTER-Net observations report
  13. GRB 251006B: Fermi GBM Observation
  14. GRB 251006B/EP251006a: EP-FXT afterglow detection
  15. GRB 251006B: Insight-HXMT detection
  16. EP251003a: LCO and VST fading optical counterpart
  17. GRB 251006B/EP251006a: SVOM/VT optical candidate
  18. GRB 251006B/EP251006a: EP-FXT follow-up observation
  19. GRB 251006B: COLIBRÍ optical upper limit
  20. GRB 251006B/EP251006a: EP-WXT detection
  21. EP251003a: Einstein Probe detection of an X-ray transient
  22. Fermi GBM Sub-Threshold Detection of GRB 250910A
  23. EP250821a: iTelescope T-59 possible detection of the optical counterpart
  24. GRB 251002A: Swift-XRT afterglow detection
  25. GRB 251002A: EP-FXT counterpart detection
  26. GRB 250925A/EP250925a: EP-WXT detection
  27. Konus-Wind detection of GRB 250920C
  28. EP250911a: e-MERLIN radio observations
  29. Konus-Wind detection of GRB 250920B
  30. Konus-Wind detection of GRB 250920A
  31. Konus-Wind detection of GRB 250911A
  32. GRB 250919A / EP250919a: LCO optical observation
  33. Konus-Wind detection of GRB 250919A
  34. GRB 250919A / EP250919a: Insight-HXMT detection
  35. GRB 250919A/EP250919a: SVOM/VT optical observation
  36. GRB 250919A / EP250919a: MASTER bright afterglow detection 24h after GRB time
  37. GRB 250919A: Fermi GBM Observation
  38. GRB 250919A / EP250919a: NuSTAR detection of bright prompt emission
  39. GRB 250919A: Swift-XRT afterglow detection
  40. GRB 250919A: Fermi-LAT detection
  41. EP250919a/GRB 250919A: Gemini/GMOS-S spectroscopic redshift z = 1.145
  42. EP250919a: Global MASTER-Net observations report
  43. EP250919a: Einstein Probe detection of an X-ray transient
  44. Correction for GCN 41877: EP-WXT ID is 01709243841
  45. The EP-WXT trigger 01709243841: Las Cumbres discovery of the optical counterpart
  46. EP250916a: EP-FXT follow-up observation
  47. The EP-WXT trigger 01709241037 is likely a flaring star
  48. EP250916a: Einstein Probe detection of an X-ray transient
  49. The EP-WXT trigger 01709240768 is likely a flaring star
  50. EP250911a: Global MASTER-Net observations report
  51. EP250908c: tentative VLT/FORS2 redshift z = 2.87
  52. EP250911a: Upper limit from Fermi-GBM Observations
  53. EP250911a: refined analysis of the EP-WXT and EP-FXT observations
  54. EP250911a: SVOM/VT optical observation
  55. EP250911a: Swift-XRT observations
  56. EP250911a: Optical detection with Kinder observations
  57. GRB 250910A / EP250910a: Swift-XRT afterglow detection
  58. GRB 250910A / EP250910a: SVOM/VT afterglow confirmation
  59. GRB 250910A / EP250910a : VLT/HAWK-I NIR counterpart discovery
  60. EP250911a: LCO optical counterpart discovery
  61. EP250910a: Global MASTER-Net observations report
  62. EP250911a: Einstein Probe detection of an X-ray transient
  63. GRB 250404A / EP250404a: spectroscopic redshift at z = 1.88 (correction to GCN 40084)
  64. GRB 250910A / EP250910a: VLT/HAWK-I near-infrared observations
  65. EP250910a/GRB 250910A: EP-WXT detection of a fast X-ray transient
  66. EP250908b/EP#01709240653: Swift/UVOT Detection
  67. EP#01709240653: Swift-XRT observations
  68. The EP-WXT trigger 01709240674 is triggered by the known source SS Cyg
  69. EP250908c: refined analysis of the EP-WXT and EP-FXT observations
  70. EP250908c: SVOM/VT optical observation
  71. EP250908c: VLT/FORS2 optical counterpart identification
  72. EP250908b: SVOM/VT optical candidate (Coordinate supplement for GCN 41758)
  73. EP250908b: SVOM/VT optical candidate
  74. The EP-WXT trigger EP250908a/01709240652 is not a real source
  75. EP250908c: Global MASTER-Net observations report
  76. EP250908c: Einstein Probe detection of an X-ray transient
  77. EP250908b: EP-WXT detection of a fast X-ray transient and EP-FXT observation
  78. EP#01709240652 (possibly EP250908a): FTW optical and NIR observations
  79. EP250905a: Liverpool Telescope i-band upper limits
  80. EP250905b: EP-FXT follow-up observation
  81. EP250905a: refined analysis of the EP-WXT and EP-FXT observations
  82. EP250905b: Global MASTER-Net observations report
  83. EP250905b: EP-WXT detection of a fast X-ray transient
  84. EP250905a: JinShan likely optical counterpart detection
  85. EP250905a: Global MASTER-Net observations report
  86. EP250905a: Einstein Probe detection of an X-ray transient
  87. EP detected a brightening of LMXB 1ES 1735-26.9
  88. EP250827a and EP250827b: Upper limit from Fermi-GBM Observations
  89. EP250903a: Swift-XRT observations
  90. EP#01709201209: Swift-XRT observations
  91. EP250903a: retraction of the LCO candidate, and discovery of the likely counterpart
  92. EP-WXT trigger 01709201209: Liverpool Telescope upper limits
  93. EP250903a: refined analysis of the EP-WXT and EP-FXT observations
  94. The EP-WXT trigger 01709201209 is likely a flaring star
  95. GRB 250903A: EP-FXT counterpart detection
  96. EP250903a: SVOM/VT optical confirmation
  97. EP250901a: Mondy, Assy and SAO RAS optical limits
  98. EP250903a: LCO candidate counterpart discovery
  99. EP250903a: Global MASTER-Net observations report
  100. EP250903a: TRT optical observations

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