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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. GRB 050820A BAT observations of second, larger episode of emission
  2. GRB050813: Maidanak I-band observations
  3. GRB 050822: Swift-BAT refined analysis
  4. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  5. GRB050820B at FRAM
  6. GRB050820A: RTT150 optical observations
  7. GRB 050820a - corrections to GCN 3846
  8. Swift/UVOT UV Photometry of GRB 050820B
  9. GRB 050822: ROTSE-III Prompt Optical Limits
  10. GRB 050822: Swift detection of a long burst
  11. Correction to Eiso calculation in GCN 3835 on GRB 050820A
  12. GRB050820A: Radio Observation
  13. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  14. GRB050820a BVRcIc field photometry
  15. GRB050820B XMM-Newton observation
  16. GRB 050820a: NIR Observations by WIRO
  17. GRB 050820B: Swift XRT position
  18. GRB050820B: Planned XMM-Newton observation
  19. GRB050820B: Refined analysis of the Swift-BAT burst
  20. GRB050820B: BAT-Swift detection of a bright GRB
  21. Swift/UVOT photometry of GRB050820
  22. GRB050820: refined XRT analysis
  23. GRB 050820: Early RAPTOR detections
  24. GRB 050820 Swift-BAT refined analysis
  25. GRB 050820: P60 Temporal Decay Index
  26. GRB 050820: High Resolution Spectroscopy from Keck
  27. GRB050819: refined XRT analysis
  28. GRB050819: RTT150 optical observations
  29. GRB 050820: Swift detection of a GRB
  30. GRB050820: Optical afterglow from P60
  31. GRB 050819 Swift-BAT refined analysis
  32. GRB050819: Swift XRT position
  33. GRB050819: Swift-BAT detection of a weak burst
  34. Swift-BAT trigger 150993 is not a GRB
  35. Swift Trigger 150823 is HETE J1900.1-2455
  36. GRB 050817: Optical observations
  37. GRB 050815: Radio Observation
  38. GRB050814: Radio Observation
  39. GRB050817: Negative Optical Observations
  40. GRB050817: Swift-BAT Detection of a burst
  41. GRB 050814: continued fading
  42. GRB050815: Optical afterglow detection by Swift UVOT
  43. GRB050815: XRT refined analysis
  44. GRB 050813: Radio Observations
  45. GRB050815: Refined analysis of the Swift-BAT burst
  46. GRB 050815: ROTSE-III Optical Limits
  47. GRB050815: Swift XRT afterglow localization
  48. GRB050815: Swift-BAT detection of a burst
  49. GRB 050730: Third Epoch WSRT Radio Observations
  50. GRB050814: Fading red source
  51. GRB 050813: Gemini Spectra Revisited
  52. GRB050814: P60 Optical Afterglow Candidate
  53. GRB 050813: Non-fading of afterglow candidate
  54. GRB 050814: XRT refined analysis
  55. GRB050814: SWIFT/UVOT observation
  56. GRB050814: Refined analysis of the Swift-BAT burst
  57. GRB050813: Gemini Imaging
  58. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  59. GRB 050814: Swift XRT Afterglow Localization
  60. GRB 050814: Swift detection of a burst
  61. GRB 050813: Magellan detection of a high redshift galaxy cluster
  62. GRB050813: RTT150 optical observations
  63. GRB 050813: I-band observations
  64. GRB050813, SDSS pre-burst observations
  65. GRB 050813: KAIT optical limit
  66. GRB 050813: Swift-BAT refined analysis
  67. GRB 050813: Photometry of object in XRT error circle
  68. GRB050813: SWIFT/UVOT observation
  69. GRB 050813: Swift XRT afterglow localization
  70. RBO GRB 050714A and GRB 050716 observations
  71. GRB 050813: Possible Short Swift-BAT GRB
  72. GRB050813 (Swift 150139): P60 Observations
  73. Swift-BAT trigger 150131 is not a GRB
  74. GRB050807(=H3889): An X-Ray Rich GRB Localized by HETE
  75. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  76. GRB050803: CrAO optical observations, no OT candidate
  77. Detection of an intermediate burst from SGR 1806-20 on August 8
  78. GRB 050730: WSRT Radio Observations
  79. GRB 050803: PROMPT BVRcIc Observations
  80. GRB 050807: ROTSE-III Optical Limits
  81. GRB 050730, optical observation
  82. GRB050805b: CrAO optical limit
  83. GRB050805a : Null detection report
  84. GRB050730, optical observations
  85. GRB050803, optical observations
  86. Swift-BAT trigger 149118 is very likely not a GRB
  87. Retraction of Swift Trigger 149131 (GRB 050805B)
  88. GRB 050805b: OHP optical limits
  89. GRB 050805b: TAROT optical limits
  90. GRB050805b: MASTER optical observations
  91. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  92. GRB050805a: MASTER optical candidat
  93. Swift-BAT trigger 149118 is probably not a GRB
  94. GRB050802: TNG optical observations
  95. GRB050803: Radio Observation
  96. GRB 050803: RTT150 optical observations
  97. GRB050801: Radio Observation
  98. GRB050730: Radio Detection
  99. GRB050803: CrAO optical observations, possible OT candidate
  100. GRB050803: Optical/UV Upper Limits from Swift-UVOT

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