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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"

45645 results found.

  1. GRB070521: NIR observations
  2. GRB070520B: NIR observations
  3. GRB 070521: Swift/UVOT Upper Limits
  4. GRB 070521, optical observation
  5. GRB 070521: Swift-XRT refined analysis
  6. GRB 070521: Keck imaging
  7. GRB070521: Gemini Observations
  8. GROND upper limits of GRB 070521
  9. GRB 070521 Milagro GeV/TeV Observations
  10. GRB 070520B: SARA upper limit
  11. GRB 070520A: SARA upper limit
  12. GRB 070521: SARA upper limit
  13. GRB 070521: Subaru observations and possible host detection
  14. GRB070518: Optical/NIR observation
  15. GRB 070520B: Swift/UVOT Upper Limits
  16. GRB 070520A: Subaru Observations
  17. GRB 070521, Swift-BAT refined analysis
  18. GRB 070520A: Swift UVOT Upper Limits
  19. GRB 070520B: Swift-XRT refined analysis
  20. GRB 070521: optical limit by Pi of the Sky
  21. GRB070521: P200 Observations
  22. GRB070521 : Faulkes Telescope North Observations
  23. GRB 070521: TAROT La Silla observatory optical observations
  24. GRB070521: Bright SDSS Galaxy Near XRT Error Circle
  25. GRB070521 - SDSS Pre-Burst Observations
  26. GRB 070521: Swift detection of a burst
  27. GRB 070520A: MITSuME Akeno optical upper limits
  28. GRB 070520B, Swift-BAT refined analysis
  29. GRB 070520A, Swift-BAT refined analysis
  30. GRB 070520A: Swift-XRT refined analysis
  31. GRB 070518: TNG observations
  32. GRB 070520B: Swift detection of a burst
  33. GRB 070520: Xinglong EST optical Upper Limit
  34. GRB 070520: Swift detection of a burst
  35. VLA observation of GRB 070518
  36. GRB 070518: Swift-XRT refined analysis
  37. GRB 070517: Gemini optical imaging
  38. GRB070518: UVOT refined analysis
  39. GRB070518: OSN observation
  40. GRB 070518, Swift-BAT refined analysis
  41. GRB 070518: OT confirmed form Xinglong TNT observation
  42. GRB 070518: Swift detection of a burst with optical afterglow
  43. GRB070517: Swift-XRT Refined Analysis
  44. GRB 070517, Swift-BAT refined analysis
  45. GRB 070517: Optical search
  46. GRB 070517: Swift detection of a burst
  47. GRB 070509: objects inside XRT error circle
  48. GRB 070512: pseudo-z ~ 1.39 from prompt emission spectrum
  49. GRB 070512: IPN localization and Konus spectrum of a bright burst
  50. GRB070419A: optical observations
  51. GRB 070419A, Deep LBT photometry
  52. GRB 070508: pseudo-z from 4 different spectral analyses
  53. GRB 070509: Swift/UVOT Upper Limits
  54. Konus-Wind and Konus-A observation of GRB 070508
  55. Swift-BAT trigger 278987 is not a GRB
  56. GRB 070510: Swift detection of a possible burst
  57. GRB070509: Swift-XRT Refined Analysis
  58. RHESSI Spectrum of GRB070508
  59. GRB 070508: OA fading and tentative redshift
  60. GRB 070509, Swift-BAT refined analysis
  61. GRB 070508: Suzaku/WAM observation of the prompt emission
  62. GRB 070509: REM observations
  63. GRB 070509: Swift detection of a burst
  64. GRB 070509: ROTSE-III Optical Limits
  65. GRB070508: Swift/UVOT Observations
  66. GRB 070508, SMARTS optical afterglow observation
  67. GRB 070508, Swift-BAT refined analysis
  68. GRB 070508: Multicolor optical observations and possible redshift limit
  69. GRB 070508: Swift-XRT refined analysis
  70. GRB 070508: Optical observation limiting magnitude
  71. GRB 070508: Optical afterglow detection
  72. GRB 070508: REM observations
  73. GRB 070508: TAROT La Silla observatory optical observations
  74. GRB 070508: Swift detection of an intense burst with an optical counterpart
  75. GRB070412: MAGIC telescope GeV observation
  76. Swift-BAT trigger 278809 is not a GRB
  77. GRB 070507: Swift detection of a possible cosmic ray shower event or a possible burst
  78. GRB 070506: VLT redshift
  79. GRB070506: Swift/UVOT Observations
  80. GRB070506: Swift XRT refined analysis
  81. GRB 070506, Swift-BAT Refined Analysis
  82. GRB 070506: Swift detection of a burst with optical afterglow
  83. GRB 070412, deep LBT imaging
  84. GRB 070429A: Swift XRT further analysis
  85. GRB070429B: VLT observations
  86. GRB 070429A: optical observations
  87. GRB070429B: position correction
  88. GRB 070309: Swift-XRT afterglow confirmation
  89. GRB070429B: possible host galaxy detection
  90. VLA observation of GRB 070429B
  91. Swift/UVOT observations of GRB070429B
  92. GRB 070429B, Swift-BAT refined analysis
  93. Swift/UVOT observations of GRB070429A
  94. GRB 070429A: Swift XRT refined analysis
  95. GRB 070429A, Swift-BAT refined analysis
  96. GRB 070429A: optical and NIR observations
  97. GRB 070429B: Swift XRT refined analysis
  98. GRB 070429B: ROTSE-III Optical Limits
  99. GRB 070429B: Swift detection of a short burst
  100. GRB 070429: What's the temperature?

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