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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 070612A, Swift-BAT refined analysis
  2. GRB 070612B: Swift-XRT refined analysis
  3. SWIFT J195509.6+261406 / GRB 070610: SWIFT continued observations
  4. GRB 070612B: Swift/UVOT upper limits
  5. GRB 070612B: FRAM limit
  6. GRB070612B: P60 Observations
  7. GRB 070612B: KAIT limits
  8. GRB 070612A: SARA detection of possible OT
  9. GRB 070612B: Swift XRT position from downlink data
  10. GRB 070610: TAROT Calern observatory optical observations
  11. GRB 070610: MITSuME OAO optical upper limit
  12. GRB 070612B: Swift detection of a burst
  13. GRB070612 - SDSS Pre-Burst Observations
  14. GRB 070612: Swift detection of a burst
  15. GRB 070610: OPTIMA-Burst detection of continued strong flaring activity
  16. GRB 070610: SARA upper limit
  17. GRB 070610: Swift-XRT refined analysis
  18. GRB 070610: TLS RRM sees flaring behaviour - Galactic transient?
  19. GRB 070611: Swift/UVOT Observations
  20. GRB 070611: Swift-XRT refined analysis
  21. GRB 070611, Swift-BAT refined analysis
  22. GRB 070610: Optical observations from OSN
  23. GRB 070610: Watcher Observations
  24. GRB 070611: VLT redshift
  25. GRB 060121 : pseudo-z = 1.9 ('intermediate-duration' burst)
  26. GRB 070611: ROTSE-III Detection of Late Rising Optical Counterpart
  27. GRB 070611; Swift-XRT position
  28. GRB 070611: ROTSE-III Optical Limits
  29. GRB 070611: Swift detection of a burst
  30. GRB 070610: Swift-UVOT Upper Limits
  31. GRB 070610: OPTIMA-Burst high-time-resolution optical observations
  32. GRB 070610, Swift-BAT refined analysis
  33. GRB 070610; Swift-XRT position
  34. GRB 070610: Swift detection of a burst
  35. GRB 070412: TAROT Calern observatory optical observations
  36. GRB 070411: TAROT Calern observatory optical observations
  37. GRB 070419A, deep LBT photometry and possible supernova detection
  38. GRB070520B: optical observations
  39. GRB070520: optical observation
  40. GRB070518: optical observation
  41. GRB070521: optical observation
  42. Swift/UVOT refined analysis of GRB070531
  43. GRB 070531: NOT nIR observations
  44. GRB 070531: Swift-BAT refined analysis
  45. GRB 070531: I-band observations from IAC80
  46. GRB 070531: Swift-XRT position
  47. GRB 070531: Liverpool Telescope Optical Observations
  48. GRB 070531: Swift detection of a burst
  49. GRB 070529: SARA upper limit
  50. Swift/UVOT refined analysis of GRB070529
  51. GRB 070529: MARGE Observations
  52. GRB 070529: Optical aterglow from MIRO
  53. GRB 070529: Gemini Redshift
  54. GRB 070529: Swift-XRT refined analysis
  55. GRB 070529, Swift-BAT refined analysis
  56. GRB 070529: Xinglong TNT Optical Upper Limit
  57. GRB 070529: Swift detection of a burst with an optical aterglow
  58. GRB 070412: Deep Keck imaging
  59. Swift Triggers 280447, 280450 and 280451 are invalid
  60. Swift trigger 280447 is probably a Galactic transient
  61. GRB 070518, deep LBT photometry
  62. GRB 070518: MARGE Observations
  63. GRB 070521: pseudo-z ~ 2.28 from prompt emission spectrum
  64. Konus-Wind observation of GRB 070521
  65. GRB 070518: optical observation
  66. GRB070521: Second Epoch Gemini Imaging
  67. GRB070521: NIR observations
  68. GRB070520B: NIR observations
  69. GRB 070521: Swift/UVOT Upper Limits
  70. GRB 070521, optical observation
  71. GRB 070521: Swift-XRT refined analysis
  72. GRB 070521: Keck imaging
  73. GRB070521: Gemini Observations
  74. GROND upper limits of GRB 070521
  75. GRB 070521 Milagro GeV/TeV Observations
  76. GRB 070520B: SARA upper limit
  77. GRB 070520A: SARA upper limit
  78. GRB 070521: SARA upper limit
  79. GRB 070521: Subaru observations and possible host detection
  80. GRB070518: Optical/NIR observation
  81. GRB 070520B: Swift/UVOT Upper Limits
  82. GRB 070520A: Subaru Observations
  83. GRB 070521, Swift-BAT refined analysis
  84. GRB 070520A: Swift UVOT Upper Limits
  85. GRB 070520B: Swift-XRT refined analysis
  86. GRB 070521: optical limit by Pi of the Sky
  87. GRB070521: P200 Observations
  88. GRB070521 : Faulkes Telescope North Observations
  89. GRB 070521: TAROT La Silla observatory optical observations
  90. GRB070521: Bright SDSS Galaxy Near XRT Error Circle
  91. GRB070521 - SDSS Pre-Burst Observations
  92. GRB 070521: Swift detection of a burst
  93. GRB 070520A: MITSuME Akeno optical upper limits
  94. GRB 070520B, Swift-BAT refined analysis
  95. GRB 070520A, Swift-BAT refined analysis
  96. GRB 070520A: Swift-XRT refined analysis
  97. GRB 070518: TNG observations
  98. GRB 070520B: Swift detection of a burst
  99. GRB 070520: Xinglong EST optical Upper Limit
  100. GRB 070520: Swift detection of a burst

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