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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"

26364 results found.

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

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