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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 070531: Swift-XRT position
  2. GRB 070531: Liverpool Telescope Optical Observations
  3. GRB 070531: Swift detection of a burst
  4. GRB 070529: SARA upper limit
  5. Swift/UVOT refined analysis of GRB070529
  6. GRB 070529: MARGE Observations
  7. GRB 070529: Optical aterglow from MIRO
  8. GRB 070529: Gemini Redshift
  9. GRB 070529: Swift-XRT refined analysis
  10. GRB 070529, Swift-BAT refined analysis
  11. GRB 070529: Xinglong TNT Optical Upper Limit
  12. GRB 070529: Swift detection of a burst with an optical aterglow
  13. GRB 070412: Deep Keck imaging
  14. Swift Triggers 280447, 280450 and 280451 are invalid
  15. Swift trigger 280447 is probably a Galactic transient
  16. GRB 070518, deep LBT photometry
  17. GRB 070518: MARGE Observations
  18. GRB 070521: pseudo-z ~ 2.28 from prompt emission spectrum
  19. Konus-Wind observation of GRB 070521
  20. GRB 070518: optical observation
  21. GRB070521: Second Epoch Gemini Imaging
  22. GRB070521: NIR observations
  23. GRB070520B: NIR observations
  24. GRB 070521: Swift/UVOT Upper Limits
  25. GRB 070521, optical observation
  26. GRB 070521: Swift-XRT refined analysis
  27. GRB 070521: Keck imaging
  28. GRB070521: Gemini Observations
  29. GROND upper limits of GRB 070521
  30. GRB 070521 Milagro GeV/TeV Observations
  31. GRB 070520B: SARA upper limit
  32. GRB 070520A: SARA upper limit
  33. GRB 070521: SARA upper limit
  34. GRB 070521: Subaru observations and possible host detection
  35. GRB070518: Optical/NIR observation
  36. GRB 070520B: Swift/UVOT Upper Limits
  37. GRB 070520A: Subaru Observations
  38. GRB 070521, Swift-BAT refined analysis
  39. GRB 070520A: Swift UVOT Upper Limits
  40. GRB 070520B: Swift-XRT refined analysis
  41. GRB 070521: optical limit by Pi of the Sky
  42. GRB070521: P200 Observations
  43. GRB070521 : Faulkes Telescope North Observations
  44. GRB 070521: TAROT La Silla observatory optical observations
  45. GRB070521: Bright SDSS Galaxy Near XRT Error Circle
  46. GRB070521 - SDSS Pre-Burst Observations
  47. GRB 070521: Swift detection of a burst
  48. GRB 070520A: MITSuME Akeno optical upper limits
  49. GRB 070520B, Swift-BAT refined analysis
  50. GRB 070520A, Swift-BAT refined analysis
  51. GRB 070520A: Swift-XRT refined analysis
  52. GRB 070518: TNG observations
  53. GRB 070520B: Swift detection of a burst
  54. GRB 070520: Xinglong EST optical Upper Limit
  55. GRB 070520: Swift detection of a burst
  56. VLA observation of GRB 070518
  57. GRB 070518: Swift-XRT refined analysis
  58. GRB 070517: Gemini optical imaging
  59. GRB070518: UVOT refined analysis
  60. GRB070518: OSN observation
  61. GRB 070518, Swift-BAT refined analysis
  62. GRB 070518: OT confirmed form Xinglong TNT observation
  63. GRB 070518: Swift detection of a burst with optical afterglow
  64. GRB070517: Swift-XRT Refined Analysis
  65. GRB 070517, Swift-BAT refined analysis
  66. GRB 070517: Optical search
  67. GRB 070517: Swift detection of a burst
  68. GRB 070509: objects inside XRT error circle
  69. GRB 070512: pseudo-z ~ 1.39 from prompt emission spectrum
  70. GRB 070512: IPN localization and Konus spectrum of a bright burst
  71. GRB070419A: optical observations
  72. GRB 070419A, Deep LBT photometry
  73. GRB 070508: pseudo-z from 4 different spectral analyses
  74. GRB 070509: Swift/UVOT Upper Limits
  75. Konus-Wind and Konus-A observation of GRB 070508
  76. Swift-BAT trigger 278987 is not a GRB
  77. GRB 070510: Swift detection of a possible burst
  78. GRB070509: Swift-XRT Refined Analysis
  79. RHESSI Spectrum of GRB070508
  80. GRB 070508: OA fading and tentative redshift
  81. GRB 070509, Swift-BAT refined analysis
  82. GRB 070508: Suzaku/WAM observation of the prompt emission
  83. GRB 070509: REM observations
  84. GRB 070509: Swift detection of a burst
  85. GRB 070509: ROTSE-III Optical Limits
  86. GRB070508: Swift/UVOT Observations
  87. GRB 070508, SMARTS optical afterglow observation
  88. GRB 070508, Swift-BAT refined analysis
  89. GRB 070508: Multicolor optical observations and possible redshift limit
  90. GRB 070508: Swift-XRT refined analysis
  91. GRB 070508: Optical observation limiting magnitude
  92. GRB 070508: Optical afterglow detection
  93. GRB 070508: REM observations
  94. GRB 070508: TAROT La Silla observatory optical observations
  95. GRB 070508: Swift detection of an intense burst with an optical counterpart
  96. GRB070412: MAGIC telescope GeV observation
  97. Swift-BAT trigger 278809 is not a GRB
  98. GRB 070507: Swift detection of a possible cosmic ray shower event or a possible burst
  99. GRB 070506: VLT redshift
  100. GRB070506: Swift/UVOT Observations

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