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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"

43658 results found.

  1. GRB050820A: Radio Observation
  2. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  3. GRB050820a BVRcIc field photometry
  4. GRB050820B XMM-Newton observation
  5. GRB 050820B: Swift XRT position
  6. GRB050820B: Refined analysis of the Swift-BAT burst
  7. GRB050820B: BAT-Swift detection of a bright GRB
  8. Swift/UVOT photometry of GRB050820
  9. GRB050820: refined XRT analysis
  10. GRB 050820: Early RAPTOR detections
  11. GRB 050820 Swift-BAT refined analysis
  12. GRB 050820: P60 Temporal Decay Index
  13. GRB 050820: High Resolution Spectroscopy from Keck
  14. GRB050819: refined XRT analysis
  15. GRB050819: RTT150 optical observations
  16. GRB 050820: Swift detection of a GRB
  17. GRB050820: Optical afterglow from P60
  18. GRB 050819 Swift-BAT refined analysis
  19. GRB050819: Swift XRT position
  20. GRB050819: Swift-BAT detection of a weak burst
  21. Swift-BAT trigger 150993 is not a GRB
  22. Swift Trigger 150823 is HETE J1900.1-2455
  23. GRB 050817: Optical observations
  24. GRB 050815: Radio Observation
  25. GRB050814: Radio Observation
  26. GRB050817: Negative Optical Observations
  27. GRB050817: Swift-BAT Detection of a burst
  28. GRB 050814: continued fading
  29. GRB050815: Optical afterglow detection by Swift UVOT
  30. GRB050815: XRT refined analysis
  31. GRB 050813: Radio Observations
  32. GRB050815: Refined analysis of the Swift-BAT burst
  33. GRB 050815: ROTSE-III Optical Limits
  34. GRB050815: Swift XRT afterglow localization
  35. GRB050815: Swift-BAT detection of a burst
  36. GRB 050730: Third Epoch WSRT Radio Observations
  37. GRB050814: Fading red source
  38. GRB 050813: Gemini Spectra Revisited
  39. GRB050814: P60 Optical Afterglow Candidate
  40. GRB 050813: Non-fading of afterglow candidate
  41. GRB 050814: XRT refined analysis
  42. GRB050814: SWIFT/UVOT observation
  43. GRB050814: Refined analysis of the Swift-BAT burst
  44. GRB050813: Gemini Imaging
  45. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  46. GRB 050814: Swift XRT Afterglow Localization
  47. GRB 050814: Swift detection of a burst
  48. GRB 050813: Magellan detection of a high redshift galaxy cluster
  49. GRB050813: RTT150 optical observations
  50. GRB 050813: I-band observations
  51. GRB050813, SDSS pre-burst observations
  52. GRB 050813: KAIT optical limit
  53. GRB 050813: Swift-BAT refined analysis
  54. GRB 050813: Photometry of object in XRT error circle
  55. GRB050813: SWIFT/UVOT observation
  56. GRB 050813: Swift XRT afterglow localization
  57. RBO GRB 050714A and GRB 050716 observations
  58. GRB 050813: Possible Short Swift-BAT GRB
  59. GRB050813 (Swift 150139): P60 Observations
  60. Swift-BAT trigger 150131 is not a GRB
  61. GRB050807(=H3889): An X-Ray Rich GRB Localized by HETE
  62. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  63. GRB050803: CrAO optical observations, no OT candidate
  64. Detection of an intermediate burst from SGR 1806-20 on August 8
  65. GRB 050730: WSRT Radio Observations
  66. GRB 050803: PROMPT BVRcIc Observations
  67. GRB 050807: ROTSE-III Optical Limits
  68. GRB 050730, optical observation
  69. GRB050805b: CrAO optical limit
  70. GRB050805a : Null detection report
  71. GRB050730, optical observations
  72. GRB050803, optical observations
  73. Swift-BAT trigger 149118 is very likely not a GRB
  74. Retraction of Swift Trigger 149131 (GRB 050805B)
  75. GRB 050805b: OHP optical limits
  76. GRB 050805b: TAROT optical limits
  77. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  78. Swift-BAT trigger 149118 is probably not a GRB
  79. GRB050802: TNG optical observations
  80. GRB050803: Radio Observation
  81. GRB 050803: RTT150 optical observations
  82. GRB050801: Radio Observation
  83. GRB050730: Radio Detection
  84. GRB050803: CrAO optical observations, possible OT candidate
  85. GRB050803: Optical/UV Upper Limits from Swift-UVOT
  86. GRB 050803: Keck Observations
  87. GRB 050803: Swift-BAT refined analysis
  88. GRB 050802.422: Fading of the afterglow and detection of the host
  89. GRB 050803: Magellan Observations
  90. GRB 050803: early Swift XRT analysis results
  91. GRB 050803: TAROT optical limits
  92. GRB050802: Tentative absorption redshift
  93. GRB050803: Swift-BAT detection of a very long burst
  94. GCN GRB observation 050713A
  95. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  96. GRB 050802: Swift/UVOT optical and UV detections
  97. GRB050802: CrAO optical observations
  98. GRB050801: Unchanged decay slope
  99. GRB050802 radio non-detection
  100. GRB 050730: OHP optical observations

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