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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"

4871 results found.

  1. GRB 070704: Swift-XRT refined analysis
  2. GRB 070626: IPN localization and Konus spectrum of a bright long burst
  3. GRB070621: RTT150 optical observations
  4. GRB 070621: VLT optical observations
  5. Keck Laser Guide Star Adaptive Optics Imaging of GRB 070621
  6. GRB070621: Swift XRT refined analysis
  7. GRB 070621: Gemini South optical imaging
  8. GRB 070621: UVOT-enhanced XRT position
  9. GRB 070621: NOT observations
  10. GRB 070621: ROTSE-III Prompt Optical Limits
  11. Swift XRT observations of the INTEGRAL burst GRB070615: Possible
  12. SWIFT J195509.6+261406 (GRB 070610): further observations
  13. GRB 070612A: continued SARA observations
  14. GRB 070612B: SARA upper limit
  15. GRB 070612B: KAIT limits
  16. GRB 070610: TAROT Calern observatory optical observations
  17. GRB 070611: Swift-XRT refined analysis
  18. GRB 070529: Swift-XRT refined analysis
  19. GRB 070521: Swift-XRT refined analysis
  20. GRB 070520A: Subaru Observations
  21. GRB 070520B: Swift-XRT refined analysis
  22. GRB 070521: optical limit by Pi of the Sky
  23. GRB 070521: TAROT La Silla observatory optical observations
  24. GRB 070520A: Swift-XRT refined analysis
  25. GRB 070518: Swift-XRT refined analysis
  26. GRB070517: Swift-XRT Refined Analysis
  27. GRB070509: Swift-XRT Refined Analysis
  28. Swift-BAT trigger 278809 is not a GRB
  29. GRB 070507: Swift detection of a possible cosmic ray shower event or a possible burst
  30. GRB070506: Swift XRT refined analysis
  31. GRB 070506: Swift detection of a burst with optical afterglow
  32. GRB 070429A: optical observations
  33. Swift/UVOT observations of GRB070429A
  34. GRB 070429A: Swift XRT refined analysis
  35. GRB 070429A: optical and NIR observations
  36. GRB 070429B: Swift XRT refined analysis
  37. GRB 070429: Swift detection of a burst
  38. GRB070419A, optical observation
  39. GRB 070418: Optical and IR observations with KANATA
  40. GRB 070411: Swift-XRT refined analysis
  41. GRB 070412: Gemini/GMOS afterglow candidate
  42. GRB 070412: NOT observations
  43. Suzaku ToO observation of SGR 1806-20
  44. IPN triangulation of GRB070402
  45. long burst from SGR 1806-20 detected on March 26
  46. GRB 070328: Swift/XRT Refined Analysis
  47. GRB070318: Swift UVOT indicates unusual optical/UV afterglow
  48. GRB 070311: Swift-XRT refined analysis
  49. GRB 070306, optical observation
  50. GRB 070306: ART-3 early optical and near infrared constraints
  51. GRB 070306: XRT Team Refined Analysis
  52. GRB 920925C: optical afterglow candidate
  53. VLA observation of GRB 070220
  54. GRB 070224: WHT K-band imaging
  55. GRB 070224: MASTER-Net refind analysis
  56. GRB 070224: MASTER observations
  57. GRB 070220: MITSuME Okayama Optical Observation
  58. GRB 070220: Swift-XRT Refined Analysis
  59. GRB 070219: XRT Refined Analysis
  60. GRB 070110: optical break
  61. GRB070110: Swift XRT Team refined analysis
  62. GRB 070110: Swift detection of a burst with a possible optical afterglow
  63. GRB 070107: Swift/XRT position
  64. GRB070103: Swift XRT refined analysis
  65. Retractions of previous Swift-BAT triggers
  66. GRB 050826: MDM Redshift
  67. GRB 061222B: TAROT La Silla observatory early optical observations
  68. GRB 061217: TAROT Calern observatory optical observations
  69. GRB061217 - Swift/XRT refined analysis
  70. GRB 061214(?): ROTSE-III Optical Limits
  71. GRB061121: optical observations
  72. GRB 061126: Swift-XRT refined analysis
  73. GRB 061126: Swift detection of a burst
  74. GRB 061121: MDM Continuing Optical Decay
  75. GRB 061122: Candidate Optical Afterglow
  76. GRB 061121: ART detection in Ic
  77. GRB 061121: Swift-XRT Team Refined Analysis
  78. GRB061121, optical observation
  79. GRB 061121: Swift detection of a bright burst with an optical counterpart
  80. GRB 050915B: optical afterglow
  81. GRB061025: Swift XRT refined analysis
  82. GRB061019: Swift XRT refined analysis
  83. GRB 061006: optical afterglow
  84. GRB 061006: VLT observation
  85. GRB 061006: Swift-XRT Team Refined Analysis
  86. GRB061006 (Swift 232585) might be a short-hard GRB
  87. GRB 061006: Swift detection of a burst
  88. GRB 061004: Swift-XRT Team Refined Analysis
  89. GRB 061004: Nearby 2MASS Galaxy
  90. GRB 061002: Swift-XRT Team Refined Analysis
  91. VLA observations of GRB 060926
  92. GRB 060929: Further XRT Refined Analysis
  93. GRB 060927, Swift-BAT refined analysis
  94. GRB 060923C: Gemini Observations and Afterglow Candidate
  95. GRB 060923A: Gemini Second Epoch and Afterglow Confirmation
  96. GRB 060923C: VLT J-band observations
  97. Swift detection of IGR J17497-2821 (trigger 230504)
  98. GRB 060919, Swift-BAT refined analysis
  99. GRB 060912: Swift XRT Team Refined Analysis
  100. GRB 060908, Swift/XRT refined analysis

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