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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"

26366 results found.

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

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