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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"
  1. Swift/UVOT photometry of GRB050820
  2. GRB050820: refined XRT analysis
  3. GRB 050820: Early RAPTOR detections
  4. GRB 050820 Swift-BAT refined analysis
  5. GRB 050820: P60 Temporal Decay Index
  6. GRB 050820: High Resolution Spectroscopy from Keck
  7. GRB050819: refined XRT analysis
  8. GRB050819: RTT150 optical observations
  9. GRB 050820: Swift detection of a GRB
  10. GRB050820: Optical afterglow from P60
  11. GRB 050819 Swift-BAT refined analysis
  12. GRB050819: Swift XRT position
  13. GRB050819: Swift-BAT detection of a weak burst
  14. Swift-BAT trigger 150993 is not a GRB
  15. Swift Trigger 150823 is HETE J1900.1-2455
  16. GRB 050817: Optical observations
  17. GRB 050815: Radio Observation
  18. GRB050814: Radio Observation
  19. GRB050817: Negative Optical Observations
  20. GRB050817: Swift-BAT Detection of a burst
  21. GRB 050814: continued fading
  22. GRB050815: Optical afterglow detection by Swift UVOT
  23. GRB050815: XRT refined analysis
  24. GRB 050813: Radio Observations
  25. GRB050815: Refined analysis of the Swift-BAT burst
  26. GRB 050815: ROTSE-III Optical Limits
  27. GRB050815: Swift XRT afterglow localization
  28. GRB050815: Swift-BAT detection of a burst
  29. GRB 050730: Third Epoch WSRT Radio Observations
  30. GRB050814: Fading red source
  31. GRB 050813: Gemini Spectra Revisited
  32. GRB050814: P60 Optical Afterglow Candidate
  33. GRB 050813: Non-fading of afterglow candidate
  34. GRB 050814: XRT refined analysis
  35. GRB050814: SWIFT/UVOT observation
  36. GRB050814: Refined analysis of the Swift-BAT burst
  37. GRB050813: Gemini Imaging
  38. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  39. GRB 050814: Swift XRT Afterglow Localization
  40. GRB 050814: Swift detection of a burst
  41. GRB 050813: Magellan detection of a high redshift galaxy cluster
  42. GRB050813: RTT150 optical observations
  43. GRB 050813: I-band observations
  44. GRB050813, SDSS pre-burst observations
  45. GRB 050813: KAIT optical limit
  46. GRB 050813: Swift-BAT refined analysis
  47. GRB 050813: Photometry of object in XRT error circle
  48. GRB050813: SWIFT/UVOT observation
  49. GRB 050813: Swift XRT afterglow localization
  50. RBO GRB 050714A and GRB 050716 observations
  51. GRB 050813: Possible Short Swift-BAT GRB
  52. GRB050813 (Swift 150139): P60 Observations
  53. Swift-BAT trigger 150131 is not a GRB
  54. GRB050807(=H3889): An X-Ray Rich GRB Localized by HETE
  55. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  56. GRB050803: CrAO optical observations, no OT candidate
  57. Detection of an intermediate burst from SGR 1806-20 on August 8
  58. GRB 050730: WSRT Radio Observations
  59. GRB 050803: PROMPT BVRcIc Observations
  60. GRB 050807: ROTSE-III Optical Limits
  61. GRB 050730, optical observation
  62. GRB050805b: CrAO optical limit
  63. GRB050805a : Null detection report
  64. GRB050730, optical observations
  65. GRB050803, optical observations
  66. Swift-BAT trigger 149118 is very likely not a GRB
  67. Retraction of Swift Trigger 149131 (GRB 050805B)
  68. GRB 050805b: OHP optical limits
  69. GRB 050805b: TAROT optical limits
  70. GRB050805b: MASTER optical observations
  71. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  72. GRB050805a: MASTER optical candidat
  73. Swift-BAT trigger 149118 is probably not a GRB
  74. GRB050802: TNG optical observations
  75. GRB050803: Radio Observation
  76. GRB 050803: RTT150 optical observations
  77. GRB050801: Radio Observation
  78. GRB050730: Radio Detection
  79. GRB050803: CrAO optical observations, possible OT candidate
  80. GRB050803: Optical/UV Upper Limits from Swift-UVOT
  81. GRB 050803: Keck Observations
  82. GRB 050803: Swift-BAT refined analysis
  83. GRB 050802.422: Fading of the afterglow and detection of the host
  84. GRB050803: MASTER further analys
  85. GRB 050803, optical observations
  86. GRB 050803: Magellan Observations
  87. GRB 050803: early Swift XRT analysis results
  88. GRB 050803: TAROT optical limits
  89. GRB050803: MASTER optical observations
  90. GRB050802: Tentative absorption redshift
  91. GRB050803: Swift-BAT detection of a very long burst
  92. GCN GRB observation 050713A
  93. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  94. GRB 050802: Swift/UVOT optical and UV detections
  95. GRB050802: CrAO optical observations
  96. GRB050801: Unchanged decay slope
  97. GRB050802 radio non-detection
  98. GRB 050730: OHP optical observations
  99. GRB 050802: early Swift XRT analysis results
  100. GRB 050802: Swift/UVOT observations

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