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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 070529, Swift-BAT refined analysis
  2. GRB 070529: Xinglong TNT Optical Upper Limit
  3. GRB 070529: Swift detection of a burst with an optical aterglow
  4. GRB 070412: Deep Keck imaging
  5. Swift Triggers 280447, 280450 and 280451 are invalid
  6. Swift trigger 280447 is probably a Galactic transient
  7. GRB 070518, deep LBT photometry
  8. GRB 070518: MARGE Observations
  9. GRB 070521: pseudo-z ~ 2.28 from prompt emission spectrum
  10. Konus-Wind observation of GRB 070521
  11. GRB 070518: optical observation
  12. GRB070521: Second Epoch Gemini Imaging
  13. GRB070521: NIR observations
  14. GRB070520B: NIR observations
  15. GRB 070521: Swift/UVOT Upper Limits
  16. GRB 070521, optical observation
  17. GRB 070521: Swift-XRT refined analysis
  18. GRB 070521: Keck imaging
  19. GRB070521: Gemini Observations
  20. GROND upper limits of GRB 070521
  21. GRB 070521 Milagro GeV/TeV Observations
  22. GRB 070520B: SARA upper limit
  23. GRB 070520A: SARA upper limit
  24. GRB 070521: SARA upper limit
  25. GRB 070521: Subaru observations and possible host detection
  26. GRB070518: Optical/NIR observation
  27. GRB 070520B: Swift/UVOT Upper Limits
  28. GRB 070520A: Subaru Observations
  29. GRB 070521, Swift-BAT refined analysis
  30. GRB 070520A: Swift UVOT Upper Limits
  31. GRB 070520B: Swift-XRT refined analysis
  32. GRB 070521: optical limit by Pi of the Sky
  33. GRB070521: P200 Observations
  34. GRB070521 : Faulkes Telescope North Observations
  35. GRB 070521: TAROT La Silla observatory optical observations
  36. GRB070521: Bright SDSS Galaxy Near XRT Error Circle
  37. GRB070521 - SDSS Pre-Burst Observations
  38. GRB 070521: Swift detection of a burst
  39. GRB 070520A: MITSuME Akeno optical upper limits
  40. GRB 070520B, Swift-BAT refined analysis
  41. GRB 070520A, Swift-BAT refined analysis
  42. GRB 070520A: Swift-XRT refined analysis
  43. GRB 070518: TNG observations
  44. GRB 070520B: Swift detection of a burst
  45. GRB 070520: Xinglong EST optical Upper Limit
  46. GRB 070520: Swift detection of a burst
  47. VLA observation of GRB 070518
  48. GRB 070518: Swift-XRT refined analysis
  49. GRB 070517: Gemini optical imaging
  50. GRB070518: UVOT refined analysis
  51. GRB070518: OSN observation
  52. GRB 070518, Swift-BAT refined analysis
  53. GRB 070518: OT confirmed form Xinglong TNT observation
  54. GRB 070518: Swift detection of a burst with optical afterglow
  55. GRB070517: Swift-XRT Refined Analysis
  56. GRB 070517, Swift-BAT refined analysis
  57. GRB 070517: Optical search
  58. GRB 070517: Swift detection of a burst
  59. GRB 070509: objects inside XRT error circle
  60. GRB 070512: pseudo-z ~ 1.39 from prompt emission spectrum
  61. GRB 070512: IPN localization and Konus spectrum of a bright burst
  62. GRB070419A: optical observations
  63. GRB 070419A, Deep LBT photometry
  64. GRB 070508: pseudo-z from 4 different spectral analyses
  65. GRB 070509: Swift/UVOT Upper Limits
  66. Konus-Wind and Konus-A observation of GRB 070508
  67. Swift-BAT trigger 278987 is not a GRB
  68. GRB 070510: Swift detection of a possible burst
  69. GRB070509: Swift-XRT Refined Analysis
  70. RHESSI Spectrum of GRB070508
  71. GRB 070508: OA fading and tentative redshift
  72. GRB 070509, Swift-BAT refined analysis
  73. GRB 070508: Suzaku/WAM observation of the prompt emission
  74. GRB 070509: REM observations
  75. GRB 070509: Swift detection of a burst
  76. GRB 070509: ROTSE-III Optical Limits
  77. GRB070508: Swift/UVOT Observations
  78. GRB 070508, SMARTS optical afterglow observation
  79. GRB 070508, Swift-BAT refined analysis
  80. GRB 070508: Multicolor optical observations and possible redshift limit
  81. GRB 070508: Swift-XRT refined analysis
  82. GRB 070508: Optical observation limiting magnitude
  83. GRB 070508: Optical afterglow detection
  84. GRB 070508: REM observations
  85. GRB 070508: TAROT La Silla observatory optical observations
  86. GRB 070508: Swift detection of an intense burst with an optical counterpart
  87. GRB070412: MAGIC telescope GeV observation
  88. Swift-BAT trigger 278809 is not a GRB
  89. GRB 070507: Swift detection of a possible cosmic ray shower event or a possible burst
  90. GRB 070506: VLT redshift
  91. GRB070506: Swift/UVOT Observations
  92. GRB070506: Swift XRT refined analysis
  93. GRB 070506, Swift-BAT Refined Analysis
  94. GRB 070506: Swift detection of a burst with optical afterglow
  95. GRB 070412, deep LBT imaging
  96. GRB 070429A: Swift XRT further analysis
  97. GRB070429B: VLT observations
  98. GRB 070429A: optical observations
  99. GRB070429B: position correction
  100. GRB 070309: Swift-XRT afterglow confirmation

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