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

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