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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"

20502 results found.

  1. GRB 050520: P200 Observations
  2. GRB 050520: TAROT optical limit
  3. GRB 050520: Swift XRT position
  4. GRB 050520: VLT/ULTRACAM observations
  5. GRB 050509B and short GRB-SN association? (corrected)
  6. GRB 050509B and short GRB-SN association?
  7. GRB050502b: Early Observation
  8. GRB050509b, Bok telescope B-band imaging
  9. GRB050509b, SDSS pre-burst observations
  10. GRB 050509b: Keck/Chandra Cross-Correlation
  11. GRB 050509b: Keck/Chandra Cross-Correlation
  12. Chandra observation of GRB 050509b
  13. GRB 050509b: RAPTOR deep, early limits.
  14. GRB050509B: Optical observations at the Very Large Telescope
  15. GRB 050509b: No Optical Variability in XRT Error Circle
  16. GRB 050509c: ROTSE-III Optical Limits
  17. GRB 050505, early TAROT observation
  18. GRB050509c: REM NIR and Optical observations
  19. GRB 050505: SARA Observations
  20. Swift UVOT Follow-up Observations of GRB 050509B
  21. GRB 050509A: Optical observations
  22. GRB050509b: Radio Observations
  23. GRB 050509B: ROTSE-III Optical Limits
  24. Swift Detection of GRB050509b: A short duration burst
  25. Swift Detection of the Burst GRB050509
  26. GRB 050505: Keck I-band Magnitude
  27. GRB 050505, simultaneous optical observation
  28. GRB 050505: Further Swift UVOT observations.
  29. GRB050505: AAVSO observations
  30. GRB050416A : 1 GHz limit from GMRT
  31. GRB 050505 UVOT
  32. GRB050505: Optical Afterglow Candidate
  33. GRB 050416b:Swift XRT afterglow upper limits
  34. GRB 050416b:Swift XRT afterglow upper limits
  35. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  36. GRB050502b: Afterglow Confirmation
  37. GRB050502: P200 Observations (Correction)
  38. GRB050502: P200 Observations
  39. Swift UVOT observation of GRB 050504
  40. GRB050504: P60 Observations
  41. GRB (?) 050504: IR Observations, Intriguing Source
  42. GRB 050502b, Optical observations
  43. GRB050502a: P60 Observations (Correction)
  44. GRB050502a: P60 Observations
  45. Renewal of SGR 1806-20 activity
  46. GRB050502A: Optical Observations
  47. GRB050502B Swift-BAT refined analysis
  48. GRB 050502b: Swift XRT Position
  49. Swift Detection of the Bright Burst GRB050502b
  50. GRB050502: ANU 1m optical Observations
  51. GRB 050502: ROTSE-III Detection of Possible Counterpart
  52. Swift/BAT possible detection of a weak burst GRB050430
  53. GRB050416a: Radio Detection
  54. GRB 050422: Swift-UVOT observation
  55. GRB 050422: Swift XRT Position
  56. Swift Detection of GRB 050422
  57. GRB 050421: SLOTIS observations
  58. GRB 050421: Further Analysis of IR imaging
  59. GRB050421: Radio Observations
  60. GRB050421: Radio Observations
  61. GRB 050421: IR Observations
  62. GRB 050421: ROTSE-III Optical Limits
  63. GRB050421
  64. GRB 050421: early Swift XRT analysis results
  65. GRB 050421: NIR observations
  66. GRB050421: P60 Observations
  67. GRB 050421: BOOTES-2 simultaneous optical observations
  68. Swift Detection of GRB050421
  69. GRB 050416b: Tentative Swift XRT Position
  70. GRB 050315: potential host galaxy
  71. GRB050326: analysis of the XMM-Newton observation
  72. GRB050418: Null Optical Observations
  73. GRB 050412: Chandra observations
  74. GRB050416A, optical observations
  75. GRB 050418: Swift-BAT refined analysis
  76. GRB 050416: Mitsume optical observation
  77. GRB 050416b: LCO observations
  78. GRB 050416b: LCO observations
  79. GRB050416B: IR observations
  80. GRB 050416: Swift/UVOT refined analysis
  81. Swift-BAT detection of GRB 050416b
  82. GRB050412: Radio Observations
  83. GRB 050416: Swift/UVOT detection of afterglow emission
  84. GRB050416: Refined Swift-XRT analysis
  85. GRB 050416,optical observation
  86. GRB050416: P200 NIR Observations
  87. GRB 050416: Swift XRT Position
  88. GRB 050416: Radio observations
  89. Swift BAT/XRT Detection of GRB 050416
  90. GRB 050412: Subaru observations
  91. GRB 050408: RTT150 optical observations
  92. GRB 050412: PROMPT VRcIc Observations
  93. GRB 050408: Kuiper 1.5m observations
  94. GRB 050412: optical observations
  95. GRB 050412: early Swift XRT analysis results
  96. GRB 050412: Swift-BAT refined analysis
  97. GRB 050412: Early Optical/Ultraviolet Observations with
  98. GRB 050408: SDSS Field Calibration
  99. GRB050412: P60 Observations
  100. GRB 050412: Swift XRT Position

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