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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"

15743 results found.

  1. GRB 090621B: MAGIC telescope GeV observation
  2. GRB 090621A: MAGIC telescope GeV observation
  3. GRB 090809: afterglow confirmation at the NOT
  4. GRB 090809: Swift detection of a burst with a possible optical counterpart
  5. GRB 090807: MITSuME optical upper limit
  6. GRB 090807: Swift/UVOT Upper Limits
  7. GRB 090807, RIMOTS optical upper limits
  8. GRB 090726: optical observation
  9. GRB 090727: GRT Optical Observation
  10. GRB 090727: optical observations
  11. GRB 090726: GRT Optical Observation
  12. GRB 090728: Swift/UVOT Upper Limits
  13. GRB 090727: I-band observations from 1.23m CAHA
  14. GRB 090728, RIMOTS optical upper limits
  15. GRB 090728A: Faulkes Telescope North Optical Afterglow Candidate
  16. GRB 090727: Liverpool Telescope Afterglow Confirmation and Optical Flare
  17. GRB 090715B: Late-time Lick 3m observations
  18. GRB 090726: D50 optical observations
  19. GRB090726: 6-meter telescope redshift
  20. GRB 090726: optical transient candidate
  21. GRB 090720: Gemini-North Imaging and Optical Afterglow
  22. Swift XRT and UVOT refned analysis of GRB 090720
  23. GRB 090715B: further NOT optical observations
  24. GRB 090709A - CARMA mm Observations
  25. GRB 090715B: Lick observations
  26. GRB 090715B: MASTER optical limit
  27. GRB 090715B: Swift/UVOT followup observations
  28. GRB 090715B: break in the optical afterglow decay
  29. GRB 090715B: Observation of the optical afterglow
  30. GRB 090715B: NOT optical observations
  31. GRB 090715B - Liverpool Telescope Optical Afterglow Candidate
  32. GRB 090715B: Swift detection of a burst with a possible optical counterpart
  33. GRB 090715A: ROTSE-III Optical Limits
  34. GRB090713 optical limit by "Pi of the Sky"
  35. GRB 090709A: Xinglong TNT optical upper limit
  36. GRB 090621B: MTM-500 optical observations
  37. GRB 090709A: deep optical observation with the 10.4m GTC
  38. GRB 090709A: NOT optical observations
  39. GRB 090709A, RIMOTS optical upper limits
  40. GRB 090709A: Subaru NIR observation
  41. GRB 090709: ROTSE-III Optical Limits
  42. GRB 090708: Early RAPTOR Optical Limits
  43. GRB 090708: ROTSE-III Optical Limits
  44. XRF 090702 : RTT150 optical observations
  45. GRB 090618: Mondy optical observations
  46. GRB 090529: CrAO optical upper limit
  47. GRB 090529: MTM-500 optical observations
  48. GRB 090529: Mt.Terskol optical observations
  49. GRB 090313: optical observations
  50. XRF 090702: VLT imaging
  51. GRB 090404: Deep optical imaging and possible host association (correction)
  52. GRB 090404: Deep optical imaging and possible host association
  53. GRB 090618: RTT150 optical observations
  54. GRB080628: SAO RAS optical observations
  55. GRB 090628: 1.23m CAHA optical observations
  56. GRB 090625B: GROND upper limits
  57. GRB090618: HCT optical observations
  58. GRB 090621B: GRT Optical Observation
  59. GRB 090621A: GRT Optical Observation
  60. PAIRITEL observations of GRB 090618
  61. GRB 090621B: Gemini spectrum of afterglow candidate
  62. GRB 090621B: P60 Observations
  63. GRB 090621B: Swift/UVOT Upper Limits
  64. GRB 090621B: RTT150 optical observations
  65. GRB 090618: RTT150 optical observations
  66. GRB 090621B: Optical Observations
  67. GRB 090621: Swift/UVOT Upper Limits
  68. GRB 090618: BOAO V-band Observation
  69. GRB 090618: ZTSh optical observations
  70. GRB090618, underlying supernova search
  71. GRB090618: OAA-OAUV Optical observations
  72. VLA radio detection of GRB 090618
  73. GRB090618 - Continued optical monitoring and light curve break
  74. GRB090618: Swift/UVOT bright afterglow detection
  75. GRB 090618: SDSS host detection
  76. GRB 090618 Faulkes Telescope North observations
  77. Optical observations of GRB 090618
  78. GRB 090618: ROTSE-III Detection of Optical Counterpart
  79. GRB 090618: KAIT optical afterglow
  80. GRB090618: P60 Optical Afterglow
  81. GRB 090618: Swift detection of a bright burst with optical afterglow
  82. GRB 090424: WSRT Radio Observations
  83. GRB 090423: WSRT Radio Observations
  84. GRB 090607: Swift/UVOT Upper Limits
  85. GRB 090607: GRAS001 optical observations
  86. GRB 090530: Further NOT optical observations
  87. GRB 090530: RTT150 Optical Observation
  88. GRB 090529A: RTT150 Optical Observations
  89. GRB090529: Further NOT optical observations
  90. GRB 090531b, SMARTS optical/IR observations
  91. GRB 090531B: GROND observation
  92. GRB 090530: Early RAPTOR Optical Observations
  93. GRB090529B: ROVOR Upper Limits
  94. GRB 090531B, RIMOTS optical upper limits
  95. GRB 090531B: Swift/UVOT Upper Limits
  96. GRB 090528B: MASTER-II Kourovka optical limit
  97. GRB 090529: MITSuME optical observation
  98. GRB 090530: GRT Optical Observation
  99. GRB 090531B: ROTSE-III Optical Limits
  100. GRB090530: R-band Observation

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