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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"

26368 results found.

  1. GRB050904: P60 Observations
  2. GRB 050904: TAROT optical limits
  3. GRB 050827 : OSN 1.5m optical observations
  4. GRB 050827: P200 NIR Observations
  5. GRB050827: Swift/UVOT upper limits
  6. GRB 050827: Optical Limit
  7. GRB 050827: XRT possible afterglow detection
  8. GRB 050826 : Lulin R band observation
  9. GRB050824: Maidanak optical limits
  10. GRB 050827: Swift-BAT refined analysis
  11. Subaru Observations of GRB050724
  12. GRB 050826: Optical Candidate
  13. GRB 050826: Swift XRT preliminary analysis results
  14. GRB 050826: BAT refined analysis
  15. GRB050826: Swift/UVOT early upper limits
  16. GRB050826: Swift-BAT detection of a long burst
  17. GRB050824: MASTER final analysis of the OT observations
  18. Swift-BAT trigger 152038 is probably not a GRB
  19. GRB 050824: XRT refined analysis and possible afterglow detection
  20. GRB 050824: BAT refined analysis of a soft weak burst
  21. GRB050824: MASTER:OT decay
  22. GRB050824: MASTER observation OT
  23. GRB050805a: MASTER optical candidat
  24. XRF050509c: Radio upper limits from GMRT
  25. GRB050822: Swift/UVOT upper limits
  26. GRB 050820A BAT observations of second, larger episode of emission
  27. GRB050813: Maidanak I-band observations
  28. GRB 050822: Swift-BAT refined analysis
  29. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  30. GRB050820B at FRAM
  31. Swift/UVOT UV Photometry of GRB 050820B
  32. GRB 050822: Swift detection of a long burst
  33. GRB050820a BVRcIc field photometry
  34. GRB050820B XMM-Newton observation
  35. GRB 050820a: NIR Observations by WIRO
  36. GRB 050820B: Swift XRT position
  37. GRB050820B: Refined analysis of the Swift-BAT burst
  38. GRB050820: refined XRT analysis
  39. GRB 050820 Swift-BAT refined analysis
  40. GRB050819: refined XRT analysis
  41. GRB 050820: Swift detection of a GRB
  42. GRB 050819 Swift-BAT refined analysis
  43. GRB050819: Swift-BAT detection of a weak burst
  44. GRB 050817: Optical observations
  45. GRB050817: Negative Optical Observations
  46. GRB 050814: continued fading
  47. GRB050815: Optical afterglow detection by Swift UVOT
  48. GRB050815: XRT refined analysis
  49. GRB050815: Refined analysis of the Swift-BAT burst
  50. GRB 050815: ROTSE-III Optical Limits
  51. GRB050815: Swift-BAT detection of a burst
  52. GRB050814: Fading red source
  53. GRB050814: P60 Optical Afterglow Candidate
  54. GRB 050813: Non-fading of afterglow candidate
  55. GRB 050814: XRT refined analysis
  56. GRB050814: SWIFT/UVOT observation
  57. GRB050814: Refined analysis of the Swift-BAT burst
  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, SDSS pre-burst observations
  63. GRB 050813: Swift-BAT refined analysis
  64. GRB 050813: Photometry of object in XRT error circle
  65. GRB050813: SWIFT/UVOT observation
  66. GRB 050813: Swift XRT afterglow localization
  67. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  68. Detection of an intermediate burst from SGR 1806-20 on August 8
  69. GRB050805b: CrAO optical limit
  70. GRB050803, optical observations
  71. Retraction of Swift Trigger 149131 (GRB 050805B)
  72. GRB 050805b: OHP optical limits
  73. GRB 050805b: TAROT optical limits
  74. GRB050805b: MASTER optical observations
  75. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  76. GRB050805a: MASTER optical candidat
  77. GRB050802: TNG optical observations
  78. GRB050803: Radio Observation
  79. GRB 050803: RTT150 optical observations
  80. GRB050801: Radio Observation
  81. GRB050730: Radio Detection
  82. GRB 050803: Keck Observations
  83. GRB 050803: Swift-BAT refined analysis
  84. GRB 050802.422: Fading of the afterglow and detection of the host
  85. GRB 050803: early Swift XRT analysis results
  86. GRB 050803: TAROT optical limits
  87. GCN GRB observation 050713A
  88. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  89. GRB050802 radio non-detection
  90. GRB 050730: OHP optical observations
  91. GRB 050802: early Swift XRT analysis results
  92. GRB 050802: Swift/UVOT observations
  93. GRB 050802: Swift-BAT refined analysis
  94. GRB050801: Optical photometry and decay index
  95. GRB 050802: Swift Gamma-ray Burst
  96. GRB050801: Swift/UVOT Optical and UV detections
  97. GRB 050730: Preliminary Analysis of MIKE Spectrum
  98. GCN 050801: early Swift XRT analysis results
  99. GRB 050801: Swift-BAT refined analysis
  100. GRB 050730: XRT refined analysis

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