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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"

31728 results found.

  1. GRB070612A: MITSuME Okayama Observation
  2. GRB 070612A: continued SARA observations
  3. GRB 070612A: spectral lag
  4. GRB 070611: Watcher Observations
  5. GRB 070612A: MDM Observations
  6. GRB 070612A: P60 Confirmation of Afterglow and An Underlying, Nearby
  7. GRB 070612B: SARA upper limit
  8. GRB 070612B, Swift-BAT refined analysis
  9. GRB 070612A, Swift-BAT refined analysis
  10. GRB 070612B: Swift-XRT refined analysis
  11. SWIFT J195509.6+261406 / GRB 070610: SWIFT continued observations
  12. GRB 070612B: Swift/UVOT upper limits
  13. GRB070612B: P60 Observations
  14. GRB 070612B: KAIT limits
  15. GRB 070612A: SARA detection of possible OT
  16. GRB 070612B: Swift XRT position from downlink data
  17. GRB 070610: MITSuME OAO optical upper limit
  18. GRB070612 - SDSS Pre-Burst Observations
  19. GRB 070610: OPTIMA-Burst detection of continued strong flaring activity
  20. GRB 070610: SARA upper limit
  21. GRB 070610: Swift-XRT refined analysis
  22. GRB 070610: TLS RRM sees flaring behaviour - Galactic transient?
  23. GRB 070611: Swift/UVOT Observations
  24. GRB 070611: Swift-XRT refined analysis
  25. GRB 070611, Swift-BAT refined analysis
  26. GRB 070610: Watcher Observations
  27. GRB 070611: VLT redshift
  28. GRB 070611: ROTSE-III Detection of Late Rising Optical Counterpart
  29. GRB 070611; Swift-XRT position
  30. GRB 070611: ROTSE-III Optical Limits
  31. GRB 070610: Swift-UVOT Upper Limits
  32. GRB 070610: OPTIMA-Burst high-time-resolution optical observations
  33. GRB 070610, Swift-BAT refined analysis
  34. GRB 070610; Swift-XRT position
  35. GRB 070411: TAROT Calern observatory optical observations
  36. GRB 070419A, deep LBT photometry and possible supernova detection
  37. GRB070520B: optical observations
  38. GRB070520: optical observation
  39. GRB070518: optical observation
  40. GRB070521: optical observation
  41. Swift/UVOT refined analysis of GRB070531
  42. GRB 070531: Swift-BAT refined analysis
  43. GRB 070531: Swift-XRT position
  44. GRB 070531: Liverpool Telescope Optical Observations
  45. GRB 070529: SARA upper limit
  46. Swift/UVOT refined analysis of GRB070529
  47. GRB 070529: MARGE Observations
  48. GRB 070529: Optical aterglow from MIRO
  49. GRB 070529: Gemini Redshift
  50. GRB 070529: Swift-XRT refined analysis
  51. GRB 070529, Swift-BAT refined analysis
  52. GRB 070529: Xinglong TNT Optical Upper Limit
  53. GRB 070412: Deep Keck imaging
  54. Swift Triggers 280447, 280450 and 280451 are invalid
  55. GRB 070518, deep LBT photometry
  56. GRB 070518: MARGE Observations
  57. Konus-Wind observation of GRB 070521
  58. GRB 070518: optical observation
  59. GRB070521: Second Epoch Gemini Imaging
  60. GRB070521: NIR observations
  61. GRB070520B: NIR observations
  62. GRB 070521: Swift/UVOT Upper Limits
  63. GRB 070521, optical observation
  64. GRB 070521: Swift-XRT refined analysis
  65. GRB 070521: Keck imaging
  66. GRB070521: Gemini Observations
  67. GROND upper limits of GRB 070521
  68. GRB 070521 Milagro GeV/TeV Observations
  69. GRB 070520B: SARA upper limit
  70. GRB 070520A: SARA upper limit
  71. GRB 070521: SARA upper limit
  72. GRB 070521: Subaru observations and possible host detection
  73. GRB070518: Optical/NIR observation
  74. GRB 070520B: Swift/UVOT Upper Limits
  75. GRB 070520A: Subaru Observations
  76. GRB 070521, Swift-BAT refined analysis
  77. GRB 070520A: Swift UVOT Upper Limits
  78. GRB 070520B: Swift-XRT refined analysis
  79. GRB070521: P200 Observations
  80. GRB070521 : Faulkes Telescope North Observations
  81. GRB070521: Bright SDSS Galaxy Near XRT Error Circle
  82. GRB 070520A: MITSuME Akeno optical upper limits
  83. GRB 070520B, Swift-BAT refined analysis
  84. GRB 070520A, Swift-BAT refined analysis
  85. GRB 070520A: Swift-XRT refined analysis
  86. GRB 070518: TNG observations
  87. GRB 070520: Xinglong EST optical Upper Limit
  88. VLA observation of GRB 070518
  89. GRB 070518: Swift-XRT refined analysis
  90. GRB 070517: Gemini optical imaging
  91. GRB070518: UVOT refined analysis
  92. GRB 070518, Swift-BAT refined analysis
  93. GRB 070518: OT confirmed form Xinglong TNT observation
  94. GRB070517: Swift-XRT Refined Analysis
  95. GRB 070517, Swift-BAT refined analysis
  96. GRB 070509: objects inside XRT error circle
  97. GRB070419A: optical observations
  98. GRB 070419A, Deep LBT photometry
  99. GRB 070509: Swift/UVOT Upper Limits
  100. Konus-Wind and Konus-A observation of GRB 070508

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