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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"
  1. GRB 070610: Swift-UVOT Upper Limits
  2. GRB 070610: OPTIMA-Burst high-time-resolution optical observations
  3. GRB 070610, Swift-BAT refined analysis
  4. GRB 070610; Swift-XRT position
  5. GRB 070610: Swift detection of a burst
  6. GRB 070412: TAROT Calern observatory optical observations
  7. GRB 070411: TAROT Calern observatory optical observations
  8. GRB 070419A, deep LBT photometry and possible supernova detection
  9. GRB070520B: optical observations
  10. GRB070520: optical observation
  11. GRB070518: optical observation
  12. GRB070521: optical observation
  13. Swift/UVOT refined analysis of GRB070531
  14. GRB 070531: NOT nIR observations
  15. GRB 070531: Swift-BAT refined analysis
  16. GRB 070531: I-band observations from IAC80
  17. GRB 070531: Swift-XRT position
  18. GRB 070531: Liverpool Telescope Optical Observations
  19. GRB 070531: Swift detection of a burst
  20. GRB 070529: SARA upper limit
  21. Swift/UVOT refined analysis of GRB070529
  22. GRB 070529: MARGE Observations
  23. GRB 070529: Optical aterglow from MIRO
  24. GRB 070529: Gemini Redshift
  25. GRB 070529: Swift-XRT refined analysis
  26. GRB 070529, Swift-BAT refined analysis
  27. GRB 070529: Xinglong TNT Optical Upper Limit
  28. GRB 070529: Swift detection of a burst with an optical aterglow
  29. GRB 070412: Deep Keck imaging
  30. Swift Triggers 280447, 280450 and 280451 are invalid
  31. Swift trigger 280447 is probably a Galactic transient
  32. GRB 070518, deep LBT photometry
  33. GRB 070518: MARGE Observations
  34. GRB 070521: pseudo-z ~ 2.28 from prompt emission spectrum
  35. Konus-Wind observation of GRB 070521
  36. GRB 070518: optical observation
  37. GRB070521: Second Epoch Gemini Imaging
  38. GRB070521: NIR observations
  39. GRB070520B: NIR observations
  40. GRB 070521: Swift/UVOT Upper Limits
  41. GRB 070521, optical observation
  42. GRB 070521: Swift-XRT refined analysis
  43. GRB 070521: Keck imaging
  44. GRB070521: Gemini Observations
  45. GROND upper limits of GRB 070521
  46. GRB 070521 Milagro GeV/TeV Observations
  47. GRB 070520B: SARA upper limit
  48. GRB 070520A: SARA upper limit
  49. GRB 070521: SARA upper limit
  50. GRB 070521: Subaru observations and possible host detection
  51. GRB070518: Optical/NIR observation
  52. GRB 070520B: Swift/UVOT Upper Limits
  53. GRB 070520A: Subaru Observations
  54. GRB 070521, Swift-BAT refined analysis
  55. GRB 070520A: Swift UVOT Upper Limits
  56. GRB 070520B: Swift-XRT refined analysis
  57. GRB 070521: optical limit by Pi of the Sky
  58. GRB070521: P200 Observations
  59. GRB070521 : Faulkes Telescope North Observations
  60. GRB 070521: TAROT La Silla observatory optical observations
  61. GRB070521: Bright SDSS Galaxy Near XRT Error Circle
  62. GRB070521 - SDSS Pre-Burst Observations
  63. GRB 070521: Swift detection of a burst
  64. GRB 070520A: MITSuME Akeno optical upper limits
  65. GRB 070520B, Swift-BAT refined analysis
  66. GRB 070520A, Swift-BAT refined analysis
  67. GRB 070520A: Swift-XRT refined analysis
  68. GRB 070518: TNG observations
  69. GRB 070520B: Swift detection of a burst
  70. GRB 070520: Xinglong EST optical Upper Limit
  71. GRB 070520: Swift detection of a burst
  72. VLA observation of GRB 070518
  73. GRB 070518: Swift-XRT refined analysis
  74. GRB 070517: Gemini optical imaging
  75. GRB070518: UVOT refined analysis
  76. GRB070518: OSN observation
  77. GRB 070518, Swift-BAT refined analysis
  78. GRB 070518: OT confirmed form Xinglong TNT observation
  79. GRB 070518: Swift detection of a burst with optical afterglow
  80. GRB070517: Swift-XRT Refined Analysis
  81. GRB 070517, Swift-BAT refined analysis
  82. GRB 070517: Optical search
  83. GRB 070517: Swift detection of a burst
  84. GRB 070509: objects inside XRT error circle
  85. GRB 070512: pseudo-z ~ 1.39 from prompt emission spectrum
  86. GRB 070512: IPN localization and Konus spectrum of a bright burst
  87. GRB070419A: optical observations
  88. GRB 070419A, Deep LBT photometry
  89. GRB 070508: pseudo-z from 4 different spectral analyses
  90. GRB 070509: Swift/UVOT Upper Limits
  91. Konus-Wind and Konus-A observation of GRB 070508
  92. Swift-BAT trigger 278987 is not a GRB
  93. GRB 070510: Swift detection of a possible burst
  94. GRB070509: Swift-XRT Refined Analysis
  95. RHESSI Spectrum of GRB070508
  96. GRB 070508: OA fading and tentative redshift
  97. GRB 070509, Swift-BAT refined analysis
  98. GRB 070508: Suzaku/WAM observation of the prompt emission
  99. GRB 070509: REM observations
  100. GRB 070509: Swift detection of a burst

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