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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"

21795 results found.

  1. GRB 090621B: Swift/UVOT Upper Limits
  2. GRB 090621B: RTT150 optical observations
  3. GRB 090621B: Swift detection of a short hard burst
  4. GRB 090621: Swift/UVOT Upper Limits
  5. GRB090618: Spectrum and photometry from 6.0m BTA
  6. GRB 090621: Swift detection of a burst
  7. GRB090618: OAA-OAUV Optical observations
  8. VLA radio detection of GRB 090618
  9. GRB 090618 15GHz radio detection
  10. GRB090618 - Continued optical monitoring and light curve break
  11. GRB 090618: Swift-BAT refined analysis
  12. GRB 090618: SARA observations
  13. GRB090618: Swift/UVOT bright afterglow detection
  14. GRB 090618: SDSS host detection
  15. Swift XRT observations of GRB 090531A
  16. GRB 090618: AGILE observations
  17. GRB 090618: Enhanced Swift-XRT position
  18. GRB 090618 Faulkes Telescope North observations
  19. GRB090618: P60 Optical Afterglow
  20. GRB 090618: Swift detection of a bright burst with optical afterglow
  21. SGR 0418+5729 Fermi/GBM Detection of Pulsations
  22. GRB 090602: Suzaku WAM observation of the prompt emission
  23. GRB 090424: WSRT Radio Observations
  24. RXTE Discovery of Pulsations from SGR 0418+5729
  25. Konus-RF observation of SGR burst 090605A
  26. Discovery of a new soft gamma repeater source, SGR 0418+5729
  27. GRB 090607: Swift/UVOT Upper Limits
  28. GRB 090607: GRAS001 optical observations
  29. GRB 090607: Faulkes Telescope North observations
  30. GRB 090607: Swift detection of a burst
  31. GRB 090530B: Suzaku WAM observation of the prompt emission
  32. GRB 090530: Further NOT optical observations
  33. GRB 090530: RTT150 Optical Observation
  34. GRB 090529A: RTT150 Optical Observations
  35. GMRT observation of GRB 090424 afterglow
  36. GRB 090528: Suzaku WAM observation of the prompt emission
  37. GRB090529: Further NOT optical observations
  38. GRB 090531B: GROND observation
  39. GRB 090528B: Suzaku WAM observation of the prompt emission
  40. GRB 090530: Early RAPTOR Optical Observations
  41. GRB090529B: ROVOR Upper Limits
  42. GRB 090531A: SARA upper limit
  43. GRB 090531B: Swift/BAT spectral lag results
  44. GRB 090529C: Fermi GBM detection
  45. GRB 090530B: Fermi GBM detection
  46. Corrections to GRB 090531B Swift/UVOT Upper Limits
  47. GRB 090531B, RIMOTS optical upper limits
  48. GRB 090531B: Swift/UVOT Upper Limits
  49. GRB 090529: MITSuME optical observation
  50. GRB 090530: GRT Optical Observation
  51. GRB 090531B: Swift-XRT candidate afterglow position
  52. GRB 090531B: ROTSE-III Optical Limits
  53. GRB 090530: break in light curve
  54. GRB 090531: GROND upper limits
  55. GRB 090531: P60 Observations
  56. GRB 090529: NOT optical observations
  57. GRB 090530: NOT optical observations
  58. GRB090530: Swift/UVOT afterglow detection
  59. GRB 090530: Enhanced Swift-XRT position
  60. GRB 090530: GRAS002 refined OA analysis
  61. GRB 090530: GRAS002 optical observations
  62. GRB 090530: PAIRITEL NIR Detections
  63. GRB 090530: Swift detection of a burst with an optical counterpart
  64. GRB 090529: TLS Afterglow Observations
  65. GRB090529: UVOT/Swift detection of a brightening optical afterglow
  66. GRB 090529: Swift-BAT refined analysis
  67. GRB 090529: Enhanced Swift-XRT position
  68. GRB 090529: Preliminary Swift/UVOT Upper Limit
  69. GRB 090529: Swift detection of a burst
  70. GRB 090518 - NOT upper limit
  71. GRB 090516A: Konus-Wind and Swift/BAT joint spectral analysis
  72. GRB 090520: GROND upper limits
  73. GRB 090520 Swift-BAT detection of a burst in ground analysis
  74. GRB 090519: NOT refined analysis
  75. GRB 090519: GROND observation
  76. GRB 090519: Swift/UVOT Upper Limits
  77. GRB 090519: Enhanced Swift-XRT position
  78. GRB 090519: NOT afterglow candidate
  79. GRB 090519: FARO Chante Perdrix Observatory optical observations
  80. GRB 090519: TAROT Calern observatory optical observations
  81. GRB 090519: Swift detection of a burst
  82. GRB 090518: Swift/UVOT Upper Limits
  83. GRB 090516: Observations from Stardome Observatory
  84. GRB090518: GROND upper limits
  85. GRB 090518: P60 Observations
  86. GRB 090516, RIMOTS optical upper limits
  87. GRB090518 : Optical upper limit by MOA-II telescope
  88. GRB 090518: Enhanced Swift-XRT position
  89. GRB 090518: Swift detection of a burst
  90. GRB 090516: GROND OBSERVATIONS
  91. GRB 090516 - Zadko Telescope observations
  92. GRB 090516: NOT optical observations
  93. GRB 090516: Swift/UVOT Observations
  94. GRB 090516: Enhanced Swift-XRT position
  95. GRB 090516: Swift detection of a burst
  96. GRB 090515: VLA observations
  97. GRB 090515: Lick Upper Limits
  98. GRB 090515: ROVOR Upper Limit
  99. GRB 090515: MMT/MMIRS NIR Upper Limit
  100. GRB 090515: Swift/UVOT Observations

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