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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"

24960 results found.

  1. GRB050824: Maidanak optical limits
  2. GRB 050827: Swift-BAT refined analysis
  3. Subaru Observations of GRB050724
  4. GRB 050826: Optical Candidate
  5. GRB 050826: Swift XRT preliminary analysis results
  6. GRB 050826: BAT refined analysis
  7. GRB050826: Swift/UVOT early upper limits
  8. GRB050826: Swift-BAT detection of a long burst
  9. GRB050824: MASTER final analysis of the OT observations
  10. Swift-BAT trigger 152038 is probably not a GRB
  11. GRB 050824: XRT refined analysis and possible afterglow detection
  12. GRB 050824: BAT refined analysis of a soft weak burst
  13. GRB050824: MASTER:OT decay
  14. GRB050824: MASTER observation OT
  15. GRB050805a: MASTER optical candidat
  16. XRF050509c: Radio upper limits from GMRT
  17. GRB050822: Swift/UVOT upper limits
  18. GRB 050820A BAT observations of second, larger episode of emission
  19. GRB050813: Maidanak I-band observations
  20. GRB 050822: Swift-BAT refined analysis
  21. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  22. GRB050820B at FRAM
  23. Swift/UVOT UV Photometry of GRB 050820B
  24. GRB 050822: Swift detection of a long burst
  25. GRB050820a BVRcIc field photometry
  26. GRB050820B XMM-Newton observation
  27. GRB 050820a: NIR Observations by WIRO
  28. GRB 050820B: Swift XRT position
  29. GRB050820B: Refined analysis of the Swift-BAT burst
  30. GRB050820: refined XRT analysis
  31. GRB 050820 Swift-BAT refined analysis
  32. GRB050819: refined XRT analysis
  33. GRB 050820: Swift detection of a GRB
  34. GRB 050819 Swift-BAT refined analysis
  35. GRB050819: Swift-BAT detection of a weak burst
  36. GRB 050817: Optical observations
  37. GRB050817: Negative Optical Observations
  38. GRB 050814: continued fading
  39. GRB050815: Optical afterglow detection by Swift UVOT
  40. GRB050815: XRT refined analysis
  41. GRB050815: Refined analysis of the Swift-BAT burst
  42. GRB 050815: ROTSE-III Optical Limits
  43. GRB050815: Swift-BAT detection of a burst
  44. GRB050814: Fading red source
  45. GRB050814: P60 Optical Afterglow Candidate
  46. GRB 050813: Non-fading of afterglow candidate
  47. GRB 050814: XRT refined analysis
  48. GRB050814: SWIFT/UVOT observation
  49. GRB050814: Refined analysis of the Swift-BAT burst
  50. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  51. GRB 050814: Swift XRT Afterglow Localization
  52. GRB 050814: Swift detection of a burst
  53. GRB 050813: Magellan detection of a high redshift galaxy cluster
  54. GRB050813, SDSS pre-burst observations
  55. GRB 050813: Swift-BAT refined analysis
  56. GRB 050813: Photometry of object in XRT error circle
  57. GRB050813: SWIFT/UVOT observation
  58. GRB 050813: Swift XRT afterglow localization
  59. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  60. Detection of an intermediate burst from SGR 1806-20 on August 8
  61. GRB050805b: CrAO optical limit
  62. GRB050803, optical observations
  63. Retraction of Swift Trigger 149131 (GRB 050805B)
  64. GRB 050805b: OHP optical limits
  65. GRB 050805b: TAROT optical limits
  66. GRB050805b: MASTER optical observations
  67. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  68. GRB050805a: MASTER optical candidat
  69. GRB050802: TNG optical observations
  70. GRB050803: Radio Observation
  71. GRB 050803: RTT150 optical observations
  72. GRB050801: Radio Observation
  73. GRB050730: Radio Detection
  74. GRB 050803: Keck Observations
  75. GRB 050803: Swift-BAT refined analysis
  76. GRB 050802.422: Fading of the afterglow and detection of the host
  77. GRB 050803: early Swift XRT analysis results
  78. GRB 050803: TAROT optical limits
  79. GCN GRB observation 050713A
  80. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  81. GRB050802 radio non-detection
  82. GRB 050730: OHP optical observations
  83. GRB 050802: early Swift XRT analysis results
  84. GRB 050802: Swift/UVOT observations
  85. GRB 050802: Swift-BAT refined analysis
  86. GRB050801: Optical photometry and decay index
  87. GRB 050802: Swift Gamma-ray Burst
  88. GRB050801: Swift/UVOT Optical and UV detections
  89. GRB 050730: Preliminary Analysis of MIKE Spectrum
  90. GCN 050801: early Swift XRT analysis results
  91. GRB 050801: Swift-BAT refined analysis
  92. GRB 050730: XRT refined analysis
  93. GRB 050730: early TAROT optical observations
  94. GRB 050730, spectra and optical photometry
  95. GRB050730: Refined BAT analysis of the Swift-BAT burst
  96. GRB 050730 XMM-Newton observation
  97. GRB050730: Swift-BAT detection of a weak burst
  98. GRB050713b: Maidanak optical observations
  99. GRB 050724: Secure Host Redshift from Keck
  100. GRB 050724: WHT optical observations

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