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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"

12311 results found.

  1. GRB 121123A: NIKA (New IRAM KID Arrays) millimetre observations at the 30-m Pico Veleta telescope
  2. GRB 121209A: Swift/UVOT Upper Limits
  3. GRB 121209A: MAXI/GSC detection
  4. GRB 121211A: Continued RATIR Optical and NIR Observations, Fading
  5. GRB 121211A: RATIR Optical and NIR Observations
  6. GRB121212A: Swift/UVOT Detection
  7. GRB 121212A: Swift detection of a burst
  8. GRB 121211A: Swift/UVOT Detection
  9. GRB 121211A: MITSuME Okayama Optical Observation
  10. GRB 121209A: Keck observations
  11. GRB 121209A: EVLA Observations
  12. GRB121209A: RATIR Optical and NIR Upper Limits
  13. GRB 121209A: GROND optical afterglow candidate
  14. GRB 121209A: UVOT Observation
  15. GRB 121202A: Swift/UVOT Upper Limits
  16. GRB121202A: Swift/UVOT Observations
  17. GRB 121201A: GROND afterglow observations and photometric redshift
  18. GRB 121201A: Swift/UVOT Detection
  19. GRB 121128A: MITSuME Akeno Optical upper limits
  20. GRB 121125A: optical upper limit
  21. GRB 121128A: Swift/UVOT Detection
  22. GRB 121123A: Swift/UVOT Observations
  23. GRB 121125A: Swift/UVOT Detection
  24. GRB 121125A: MASTER-NET optical observations
  25. GRB 121123A: MASTER-NET optical limit
  26. GRB 121108A: optical upper limit
  27. Konus-Wind observation of GRB 121118B
  28. GRB 121117A: optical upper limit
  29. GRB 121117A: Swift/UVOT Observations
  30. GRB 121117A: MASTER prompt optical limit
  31. GRB 121117A: BOOTES-3 early optical upper limit
  32. GRB 121108A: Swift/UVOT Upper Limits
  33. GRB 121108A: Xinglong TNT upper limit
  34. GRB 121108A: MITSuME Ishigakijima upper limits
  35. GRB 121108A: MASTER early prompt optical limit
  36. GRB 121108A: Swift detection of a burst
  37. GRB 121028A: Swift/UVOT Upper Limits
  38. GRB 121102A: Swift/UVOT Upper Limits
  39. GRB 121031A: Swift/UVOT Upper Limits
  40. GRB 121025A: Confirmation of the X-ray afterglow
  41. GRB 121102A: Swift detection of a burst
  42. GRB 121027A: sub-mm upper limit
  43. GRB 121027A: Swift/UVOT Possible Detection
  44. GRB 121027A: MASTER early prompt optical limit
  45. GRB 121028A: MITSuME Okayama Optical upper limits
  46. GRB 121028A: Swift detection of a burst
  47. GRB 121027A: MAXI/GSC detection 40 minutes after the Swift Trigger
  48. GRB 121027A: Swift detection of a burst
  49. GRB 121024A: Swift/UVOT Observations
  50. GRB 121024A: MITSuME Ishigakijima upper limits
  51. GRB 121024A: MITSuME Okayama Optical upper limits
  52. GRB 121025A: MAXI/GSC detection
  53. Swift Trigger 536502 is likely a noise fluctuation in coincidence with SAX J1818.6-1703
  54. GRB 121017A: Swift/UVOT Upper Limits
  55. GRB 121017A: GROND Observations
  56. GRB 121017A: Swift detection of a burst
  57. PdB IRAM observation of GRB 121011A
  58. GRB 121011A: Swift/UVOT Detection
  59. Swift-BAT refined analysis of the SGR 1806-20 outburst (trigger 535747)
  60. GRB 121011A: MASTER-Net early OT light curve
  61. Trigger 535733: Swift possible detection of SAX J1828.5-1037
  62. GRB 120927A: optical upper limit
  63. GRB 121001A: GROND Afterglow Confirmation
  64. GRB 121001A: Swift/UVOT Upper Limits
  65. GRB 121001A: MASTER optical observations
  66. Swift Trigger 535026: Galactic Transient or possible GRB
  67. GRB 120927A: Swift/UVOT Upper Limits
  68. GRB 120927A: GROND upper limits
  69. GRB 120927A: Swift detection of a burst
  70. GRB 120923A: optical upper limit
  71. GRB 120923A: MITSuME Okayama Optical upper limits
  72. GRB 120923A: GROND Upper limits
  73. GRB 120922A: Swift/UVOT Detection
  74. GRB 120923A: Swift/UVOT Upper Limit
  75. GRB 120923A: Swift detection of a burst
  76. GRB 120922A: Swift detection of a burst
  77. GRB 120919B: MASTER prompt optical observations
  78. GRB 120919A: Swift/UVOT Upper Limits
  79. Swift Trigger 534017 is probably not real.
  80. Corrections to the Fermi-LAT upper limits for GRB 120807A, 120908A, 120909A, and 120911A
  81. Swift Trigger 533836 is a new Galactic transient
  82. GRB 120911A: optical upper limit CrAO
  83. GRB 120911A: optical upper limit ISON-NM
  84. GRB120911A: MITSuME Okayama Optical upper limits
  85. GRB 120911A: Fermi/LAT upper limit
  86. GRB 120911A: Swift/UVOT Upper Limits
  87. GRB 120907A: SMA upper limits
  88. GRB 120908A and GRB 120909A : Fermi/LAT upper limit
  89. GRB 120908A: Swift Observations
  90. GRB 120909A: Pi of the Sky upper limits
  91. GRB 120909A: Swift/UVOT Detection
  92. GRB 120908A: MAXI/GSC detection
  93. GRB 120907A: EVLA observations
  94. GRB 120907A: Swift/UVOT Detection
  95. GRB 120819A: optical upper limit
  96. GRB 120830A: Further Swift Observations
  97. GRB 120830A: Fermi GBM observation
  98. GRB 120830A: early MASTER optical limit
  99. Fermi trigger 368003226 : MASTER optical observations
  100. GRB 120819A: Swift/UVOT Upper Limits

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