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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"

26340 results found.

  1. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  2. GRB050820B at FRAM
  3. Swift/UVOT UV Photometry of GRB 050820B
  4. GRB 050822: Swift detection of a long burst
  5. GRB050820a BVRcIc field photometry
  6. GRB050820B XMM-Newton observation
  7. GRB 050820a: NIR Observations by WIRO
  8. GRB 050820B: Swift XRT position
  9. GRB050820B: Refined analysis of the Swift-BAT burst
  10. GRB050820: refined XRT analysis
  11. GRB 050820 Swift-BAT refined analysis
  12. GRB050819: refined XRT analysis
  13. GRB 050820: Swift detection of a GRB
  14. GRB 050819 Swift-BAT refined analysis
  15. GRB050819: Swift-BAT detection of a weak burst
  16. GRB 050817: Optical observations
  17. GRB050817: Negative Optical Observations
  18. GRB 050814: continued fading
  19. GRB050815: Optical afterglow detection by Swift UVOT
  20. GRB050815: XRT refined analysis
  21. GRB050815: Refined analysis of the Swift-BAT burst
  22. GRB 050815: ROTSE-III Optical Limits
  23. GRB050815: Swift-BAT detection of a burst
  24. GRB050814: Fading red source
  25. GRB050814: P60 Optical Afterglow Candidate
  26. GRB 050813: Non-fading of afterglow candidate
  27. GRB 050814: XRT refined analysis
  28. GRB050814: SWIFT/UVOT observation
  29. GRB050814: Refined analysis of the Swift-BAT burst
  30. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  31. GRB 050814: Swift XRT Afterglow Localization
  32. GRB 050814: Swift detection of a burst
  33. GRB 050813: Magellan detection of a high redshift galaxy cluster
  34. GRB050813, SDSS pre-burst observations
  35. GRB 050813: Swift-BAT refined analysis
  36. GRB 050813: Photometry of object in XRT error circle
  37. GRB050813: SWIFT/UVOT observation
  38. GRB 050813: Swift XRT afterglow localization
  39. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  40. Detection of an intermediate burst from SGR 1806-20 on August 8
  41. GRB050805b: CrAO optical limit
  42. GRB050803, optical observations
  43. Retraction of Swift Trigger 149131 (GRB 050805B)
  44. GRB 050805b: OHP optical limits
  45. GRB 050805b: TAROT optical limits
  46. GRB050805b: MASTER optical observations
  47. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  48. GRB050805a: MASTER optical candidat
  49. GRB050802: TNG optical observations
  50. GRB050803: Radio Observation
  51. GRB 050803: RTT150 optical observations
  52. GRB050801: Radio Observation
  53. GRB050730: Radio Detection
  54. GRB 050803: Keck Observations
  55. GRB 050803: Swift-BAT refined analysis
  56. GRB 050802.422: Fading of the afterglow and detection of the host
  57. GRB 050803: early Swift XRT analysis results
  58. GRB 050803: TAROT optical limits
  59. GCN GRB observation 050713A
  60. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  61. GRB050802 radio non-detection
  62. GRB 050730: OHP optical observations
  63. GRB 050802: early Swift XRT analysis results
  64. GRB 050802: Swift/UVOT observations
  65. GRB 050802: Swift-BAT refined analysis
  66. GRB050801: Optical photometry and decay index
  67. GRB 050802: Swift Gamma-ray Burst
  68. GRB050801: Swift/UVOT Optical and UV detections
  69. GRB 050730: Preliminary Analysis of MIKE Spectrum
  70. GCN 050801: early Swift XRT analysis results
  71. GRB 050801: Swift-BAT refined analysis
  72. GRB 050730: XRT refined analysis
  73. GRB 050730: early TAROT optical observations
  74. GRB 050730, spectra and optical photometry
  75. GRB050730: Refined BAT analysis of the Swift-BAT burst
  76. GRB 050730 XMM-Newton observation
  77. GRB050730: Swift-BAT detection of a weak burst
  78. GRB050713b: Maidanak optical observations
  79. GRB 050724: Secure Host Redshift from Keck
  80. GRB 050724: WHT optical observations
  81. GRB050713: analysis of the XMM-Newton observation
  82. Swift-BAT trigger 147918 is not a real GRB
  83. GRB050724: VLT observations of the variable source
  84. GRB050709: Second Epoch Chandra Observation
  85. GRB050726: Swift-BAT detection of a weak burst
  86. GRB 050724: Optical Variability in Nearby Galaxy
  87. GRB 050724: J-band observations
  88. GRB 050724: GMOS Imaging and Spectroscopy
  89. GRB050724: Radio Observation
  90. GRB 050724: Optical imaging/astrometry
  91. GRB 050724: Swift/UVOT Upper Limit
  92. GRB050724: Refined analysis of the Swift-BAT possible short burst
  93. GRB 050724: possible host galaxy in DSS
  94. GRB 050721A: Swift-BAT refined analysis
  95. GRB 050721A: Early Swift XRT analysis results
  96. GRB050721A: optical decay
  97. GRB 050721: optical afterglow confirmed
  98. GRB 050709: Refined Spectral and Temporal Properties
  99. GRB050714b: Radio Observation
  100. GRB050712: Radio Observations

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