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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"

28057 results found.

  1. GRB090618: HCT optical observations
  2. GRB 090618: SARA Second Epoch Observations
  3. GRB 090625B: Swift observation of the INTEGRAL GRB 090625B
  4. GRB 090625B: a long GRB localized by INTEGRAL
  5. GRB 090625: Fermi GBM detection
  6. GRB 090618: Correction to GCN 9568
  7. GRB 090617: Suzaku WAM observation of the prompt emission
  8. GRB 090618: Suzaku WAM observation of the prompt emission
  9. GRB 090621A: Enhanced Swift-XRT position
  10. GRB 090623: Fermi GBM detection
  11. GRB 090621B: GRT Optical Observation
  12. GRB 090621A: GRT Optical Observation
  13. GRB 090621B: I-band observations from 1.23m CAHA
  14. GRB 090621D: Fermi GBM detection
  15. GRB 090621C: Fermi GBM detection
  16. GRB 090621B: P60 Observations
  17. GRB 090621B: VLA observations
  18. GRB 090620: Fermi GBM detecion
  19. GRB 090621B: Swift/UVOT Upper Limits
  20. GRB 090621B: Swift-BAT refined analysis
  21. GRB 090621B: Swift-XRT refined analysis
  22. GRB 090621B: RTT150 optical observations
  23. GRB 090621B: Swift detection of a short hard burst
  24. GRB 090621: Swift/UVOT Upper Limits
  25. GRB 090621: Swift-XRT Team refined analysis
  26. GRB090618: Spectrum and photometry from 6.0m BTA
  27. GRB 090621: Swift detection of a burst
  28. GRB090618, underlying supernova search
  29. GRB090618: OAA-OAUV Optical observations
  30. GRB 090618: Fermi GBM observation
  31. GRB 090618, Swift-BAT refined spectral analysis
  32. VLA radio detection of GRB 090618
  33. GRB 090618 15GHz radio detection
  34. GRB090618 - Continued optical monitoring and light curve break
  35. GRB 090618: Swift-BAT refined analysis
  36. GRB 090618: SARA observations
  37. GRB090618: Swift-XRT team refined analysis
  38. GRB090618: Swift/UVOT bright afterglow detection
  39. GRB 090618: SDSS host detection
  40. Swift XRT observations of GRB 090531A
  41. GRB 090618: AGILE observations
  42. GRB 090617: Fermi GBM detection
  43. GRB 090618: Enhanced Swift-XRT position
  44. GRB 090618 Faulkes Telescope North observations
  45. GRB 090618: ROTSE-III Detection of Optical Counterpart
  46. GRB090618: P60 Optical Afterglow
  47. GRB 090618: Swift detection of a bright burst with optical afterglow
  48. GRB 090616: Fermi GBM detection
  49. GRB 090612: Fermi GBM detection
  50. GRB 090610C: Fermi GBM detection
  51. GRB 090610B: Fermi GBM detection
  52. GRB 090610: Fermi GBM detection
  53. SGR 0418+5729 Fermi/GBM Detection of Pulsations
  54. GRB 090602: Suzaku WAM observation of the prompt emission
  55. RXTE Discovery of Pulsations from SGR 0418+5729
  56. GRB 090531B: Fermi GBM detection
  57. Konus-RF observation of SGR burst 090605A
  58. Discovery of a new soft gamma repeater source, SGR 0418+5729
  59. GRB 090608: Fermi GBM detection
  60. GRB 090606: Fermi GBM detection
  61. GRB 090607: XRT Team Refined Analysis
  62. GRB 090607: Swift/UVOT Upper Limits
  63. GRB 090607: Swift-BAT refined analysis of the SHB
  64. GRB 090607: GRAS001 optical observations
  65. GRB 090607: Faulkes Telescope North observations
  66. GRB 090607: Swift detection of a burst
  67. GRB 090530B: Suzaku WAM observation of the prompt emission
  68. GRB 090530: Further NOT optical observations
  69. GRB 090530: RTT150 Optical Observation
  70. GRB 090602: Fermi GBM detection
  71. GRB 090529A: RTT150 Optical Observations
  72. GMRT observation of GRB 090424 afterglow
  73. GRB 090528: Suzaku WAM observation of the prompt emission
  74. GRB090529: Further NOT optical observations
  75. GRB 090531B: GROND observation
  76. GRB 090528B: Suzaku WAM observation of the prompt emission
  77. GRB 090530: Early RAPTOR Optical Observations
  78. GRB090529B: ROVOR Upper Limits
  79. GRB 090531A: SARA upper limit
  80. GRB 090531B: Swift/BAT spectral lag results
  81. GRB 090529C: Fermi GBM detection
  82. GRB 090529B: Fermi GBM detection
  83. GRB 090530B: Fermi GBM detection
  84. Corrections to GRB 090531B Swift/UVOT Upper Limits
  85. GRB 090531B, RIMOTS optical upper limits
  86. GRB 090531B: Swift/UVOT Upper Limits
  87. GRB 090528B: MASTER-II Kourovka optical limit
  88. GRB 090529: MITSuME optical observation
  89. GRB 090530: GRT Optical Observation
  90. GRB 090531B: Swift-BAT refined analysis
  91. GRB 090531B: Swift-XRT candidate afterglow position
  92. GRB 090531B: ROTSE-III Optical Limits
  93. GRB 090531: Swift-BAT refined analysis
  94. GRB090530: R-band Observation
  95. GRB 090530: break in light curve
  96. GRB 090531: GROND upper limits
  97. GRB 090531: P60 Observations
  98. GRB 090529: NOT optical observations
  99. GRB 090530: NOT optical observations
  100. GRB090530: Swift XRT refined analysis

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