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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.

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

939 results found.

  1. GRB 260916A: MAXI/GSC detection
  2. MAXI GRB260916.37: Global MASTER-Net observations report
  3. MAXI GRB260827.40: Global MASTER-Net observations report
  4. GRB260708B: MAXI/GSC detection
  5. GRB 260616C: GECAM-B observation of a burst
  6. GRB260616C: MAXI/GSC detection
  7. Fermi GRB 260602B: Global MASTER-Net observations report
  8. Fermi GRB 260602B: Global MASTER-Net observations report
  9. GRB 260531A: MAXI/GSC detection
  10. GRB 260518A: AstroSat CZTI detection of a long burst
  11. GRB 260510C: Glowbug gamma-ray detection
  12. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  13. Fermi GRB 260512A: Global MASTER-Net observations report
  14. GRB 260510C: Fermi GBM Observation
  15. GRB 260510C: AstroSat CZTI detection
  16. GRB 260510C: EP-FXT follow-up observation
  17. GRB 260510C: SVOM/VT optical upper limits
  18. GRB 260510C: MAXI/GSC detection
  19. Fermi GRB 260421B: Global MASTER-Net observations report
  20. GRID detection of GRB 260401A
  21. GRB 260401A: SVOM/GRM observation
  22. GRB 260401A: GECAM-B observation
  23. GRB 260401A: Fermi GBM Observation
  24. GRB 260401A: NuSTAR detection of prompt emission
  25. GRB 260401A: CALET Gamma-Ray Burst Monitor detection
  26. GRB 260401A: MAXI/GSC detection
  27. GRB 260304A: AstroSat CZTI detection of a long burst
  28. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  29. GRB 260206A: Swift-XRT observations
  30. GRB 260206A: Tiled Swift observations
  31. GRB 260206A (or XRB from 4U 0513-40): MAXI/GSC detection
  32. GRID detection of GRB 260131A/B
  33. GRB 260131A/B: EP/FXT X-ray afterglow detection
  34. GRB 260131A: NOT spectroscopic redshift z = 1.434
  35. Konus-Wind detection of GRB 260131A/B
  36. GRB 260131A/B: GOTO candidate optical counterpart consistent with the MAXI localisation
  37. GRB 260131A/B: Fermi GBM Observation
  38. GRB 260131B: MAXI/GSC detection
  39. GRB 251220A: MAXI/GSC detection
  40. GRB 251201A: GECAM-B observation of a burst
  41. GRB 251201A: SVOM/GRM observation of a burst
  42. GRB 251201A: MAXI/GSC detection
  43. GRB 251128A: AstroSat CZTI detection
  44. SVOM GRB 251129A : MASTER optical counterpart detection
  45. GRB 251112B: MAXI/GSC detection
  46. LIGO/Virgo/KAGRA S251112cm: Coverage and upper limits from MAXI/GSC observations
  47. GRB 251028A: Insight-HXMT/HE detection
  48. Konus-Wind detection of GRB 251028A
  49. GRB 251028A: GECAM-B detection
  50. GRB 251028A: SVOM/GRM observation
  51. GRB 251028A: Fermi GBM Observation
  52. GRB 251028A: Glowbug gamma-ray detection
  53. GRB 251028A: MAXI/GSC detection
  54. GRB 251023B: Glowbug gamma-ray detection
  55. GRB 251023B / EP#01709247298: COLIBRÍ optical counterpart candidate
  56. GRB 251023B: CALET Gamma-Ray Burst Monitor detection
  57. EP#01709247298: Swift-XRT counterpart detection
  58. GRB 251023B / MAXI J0451+122: MAXI/GSC detection
  59. GRB 250911A: MAXI/GSC detection
  60. GRB 251003A: Swift/UVOT Upper Limits
  61. LIGO/Virgo/KAGRA S250920bq: Coverage and upper limits from MAXI/GSC observations
  62. LIGO/Virgo/KAGRA S250912f: Updated Sky localization
  63. GRB 250904A: Swift/UVOT Detection
  64. GRB 250830B: Swift-XRT afterglow detection
  65. LIGO/Virgo/KAGRA S250831cc: Coverage and upper limits from MAXI/GSC observations
  66. GRB 250830B: Swift-XRT observations
  67. EP250830a/GRB 250830B: Einstein Probe detection of an X-ray transient and Swift/XRT follow-up
  68. LIGO/Virgo/KAGRA S250830bp: Coverage and upper limits from MAXI/GSC observations
  69. GRB 250830B: Swift ToO observations
  70. GRB 250830B: MAXI/GSC detection
  71. GRB 250830A / MAXI J0853+337: MAXI/GSC detection
  72. Swift GRB250823.84: Global MASTER-Net observations report
  73. LIGO/Virgo/KAGRA S250818k: Coverage and upper limits from MAXI/GSC observations
  74. GRB 250721A: Fermi GBM Observation
  75. GRB 250721A: Swift-XRT observations
  76. GRB 250721A: Tiled Swift observations
  77. GRB 250721A: MAXI/GSC detection
  78. EP250702a/GRB 250702B,C,D,E: Archival radio observations from ASKAP VAST
  79. LIGO/Virgo/KAGRA S250704ab: Coverage and upper limits from MAXI/GSC observations
  80. GRBs 250702B,C,D,E / EP250702a: SVOM/GRM observation
  81. EP250702a/GRB 250702B, C, D, E: EP-FXT follow-up observation
  82. GRBs 250702B,C,D,E / EP250702a: Konus-Wind detection of a hard X-ray transient activity
  83. GRB 250702B,C,D,E / EP 250702a: MAXI/GSC detection
  84. Fermi GRB 250606A: Global MASTER-Net observations report
  85. GRB 250527B: Swift-XRT observations
  86. GRB 250527B: Tiled Swift observations
  87. GRB 250527B / MAXI J1450-527 : MAXI/GSC detection
  88. GRB 250520A: Swift/UVOT Upper Limits
  89. MAXI GRB250515.65: Global MASTER-Net observations report
  90. EP#01709175213/IGR J19566+0326: Swift-XRT detection
  91. EP-WXT trigger 01709175213: a new X-ray outburst of LMXB MAXI J1957+032
  92. GRB 250331A: MAXI/GSC detection
  93. EP250311a/GRB 250311A: Correction to EP-WXT detection time
  94. EP250311a/GRB 250311A: EP-FXT follow-up observation
  95. GRB 250311A: Swift-XRT observations
  96. GRB 250311A/EP250311a: TRT optical upper limit
  97. GRB 250311A: Tiled Swift observations
  98. EP250311a/GRB 250311A: EP-WXT detection
  99. GRB 250311A/MAXI J1457-026: MAXI/GSC detection
  100. GRB 250305A: AstroSat CZTI detection

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