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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"

26365 results found.

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

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