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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 070521: SARA upper limit
  2. GRB 070521: Subaru observations and possible host detection
  3. GRB070518: Optical/NIR observation
  4. GRB 070520B: Swift/UVOT Upper Limits
  5. GRB 070520A: Subaru Observations
  6. GRB 070521, Swift-BAT refined analysis
  7. GRB 070520A: Swift UVOT Upper Limits
  8. GRB 070520B: Swift-XRT refined analysis
  9. GRB 070521: optical limit by Pi of the Sky
  10. GRB070521: P200 Observations
  11. GRB070521 : Faulkes Telescope North Observations
  12. GRB 070521: TAROT La Silla observatory optical observations
  13. GRB070521: Bright SDSS Galaxy Near XRT Error Circle
  14. GRB070521 - SDSS Pre-Burst Observations
  15. GRB 070521: Swift detection of a burst
  16. GRB 070520A: MITSuME Akeno optical upper limits
  17. GRB 070520B, Swift-BAT refined analysis
  18. GRB 070520A, Swift-BAT refined analysis
  19. GRB 070520A: Swift-XRT refined analysis
  20. GRB 070518: TNG observations
  21. GRB 070520B: Swift detection of a burst
  22. GRB 070520: Xinglong EST optical Upper Limit
  23. GRB 070520: Swift detection of a burst
  24. VLA observation of GRB 070518
  25. GRB 070518: Swift-XRT refined analysis
  26. GRB 070517: Gemini optical imaging
  27. GRB070518: UVOT refined analysis
  28. GRB070518: OSN observation
  29. GRB 070518, Swift-BAT refined analysis
  30. GRB 070518: OT confirmed form Xinglong TNT observation
  31. GRB 070518: Swift detection of a burst with optical afterglow
  32. GRB070517: Swift-XRT Refined Analysis
  33. GRB 070517, Swift-BAT refined analysis
  34. GRB 070517: Optical search
  35. GRB 070517: Swift detection of a burst
  36. GRB 070509: objects inside XRT error circle
  37. GRB 070512: pseudo-z ~ 1.39 from prompt emission spectrum
  38. GRB 070512: IPN localization and Konus spectrum of a bright burst
  39. GRB070419A: optical observations
  40. GRB 070419A, Deep LBT photometry
  41. GRB 070508: pseudo-z from 4 different spectral analyses
  42. GRB 070509: Swift/UVOT Upper Limits
  43. Konus-Wind and Konus-A observation of GRB 070508
  44. Swift-BAT trigger 278987 is not a GRB
  45. GRB 070510: Swift detection of a possible burst
  46. GRB070509: Swift-XRT Refined Analysis
  47. RHESSI Spectrum of GRB070508
  48. GRB 070508: OA fading and tentative redshift
  49. GRB 070509, Swift-BAT refined analysis
  50. GRB 070508: Suzaku/WAM observation of the prompt emission
  51. GRB 070509: REM observations
  52. GRB 070509: Swift detection of a burst
  53. GRB 070509: ROTSE-III Optical Limits
  54. GRB070508: Swift/UVOT Observations
  55. GRB 070508, SMARTS optical afterglow observation
  56. GRB 070508, Swift-BAT refined analysis
  57. GRB 070508: Multicolor optical observations and possible redshift limit
  58. GRB 070508: Swift-XRT refined analysis
  59. GRB 070508: Optical observation limiting magnitude
  60. GRB 070508: Optical afterglow detection
  61. GRB 070508: REM observations
  62. GRB 070508: TAROT La Silla observatory optical observations
  63. GRB 070508: Swift detection of an intense burst with an optical counterpart
  64. GRB070412: MAGIC telescope GeV observation
  65. Swift-BAT trigger 278809 is not a GRB
  66. GRB 070507: Swift detection of a possible cosmic ray shower event or a possible burst
  67. GRB 070506: VLT redshift
  68. GRB070506: Swift/UVOT Observations
  69. GRB070506: Swift XRT refined analysis
  70. GRB 070506, Swift-BAT Refined Analysis
  71. GRB 070506: Swift detection of a burst with optical afterglow
  72. GRB 070412, deep LBT imaging
  73. GRB 070429A: Swift XRT further analysis
  74. GRB070429B: VLT observations
  75. GRB 070429A: optical observations
  76. GRB070429B: position correction
  77. GRB 070309: Swift-XRT afterglow confirmation
  78. GRB070429B: possible host galaxy detection
  79. VLA observation of GRB 070429B
  80. Swift/UVOT observations of GRB070429B
  81. GRB 070429B, Swift-BAT refined analysis
  82. Swift/UVOT observations of GRB070429A
  83. GRB 070429A: Swift XRT refined analysis
  84. GRB 070429A, Swift-BAT refined analysis
  85. GRB 070429A: optical and NIR observations
  86. GRB 070429B: Swift XRT refined analysis
  87. GRB 070429B: ROTSE-III Optical Limits
  88. GRB 070429B: Swift detection of a short burst
  89. GRB 070429: What's the temperature?
  90. GRB 070429: ROTSE-III Optical Limits
  91. GRB 070429: Swift detection of a burst
  92. GRB 070427, Swift-BAT Refined Analysis
  93. LT monitoring of GRB070412
  94. GRB 070427: Swift detection of a burst
  95. GRB 070411, further deep LBT photometry
  96. GRB 070411: Late-time Keck imaging
  97. GRB 070411 : Planned XMM-Newton observation
  98. GRB070419B: Suzaku WAM observation of the prompt emission
  99. GRB 070420, SMARTS optical/IR afterglow observations
  100. GRB 070411, deep LBT photometry

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