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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"

26349 results found.

  1. GRB 050824: BAT refined analysis of a soft weak burst
  2. GRB050824: MASTER:OT decay
  3. GRB050824: MASTER observation OT
  4. GRB050805a: MASTER optical candidat
  5. XRF050509c: Radio upper limits from GMRT
  6. GRB050822: Swift/UVOT upper limits
  7. GRB 050820A BAT observations of second, larger episode of emission
  8. GRB050813: Maidanak I-band observations
  9. GRB 050822: Swift-BAT refined analysis
  10. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  11. GRB050820B at FRAM
  12. Swift/UVOT UV Photometry of GRB 050820B
  13. GRB 050822: Swift detection of a long burst
  14. GRB050820a BVRcIc field photometry
  15. GRB050820B XMM-Newton observation
  16. GRB 050820a: NIR Observations by WIRO
  17. GRB 050820B: Swift XRT position
  18. GRB050820B: Refined analysis of the Swift-BAT burst
  19. GRB050820: refined XRT analysis
  20. GRB 050820 Swift-BAT refined analysis
  21. GRB050819: refined XRT analysis
  22. GRB 050820: Swift detection of a GRB
  23. GRB 050819 Swift-BAT refined analysis
  24. GRB050819: Swift-BAT detection of a weak burst
  25. GRB 050817: Optical observations
  26. GRB050817: Negative Optical Observations
  27. GRB 050814: continued fading
  28. GRB050815: Optical afterglow detection by Swift UVOT
  29. GRB050815: XRT refined analysis
  30. GRB050815: Refined analysis of the Swift-BAT burst
  31. GRB 050815: ROTSE-III Optical Limits
  32. GRB050815: Swift-BAT detection of a burst
  33. GRB050814: Fading red source
  34. GRB050814: P60 Optical Afterglow Candidate
  35. GRB 050813: Non-fading of afterglow candidate
  36. GRB 050814: XRT refined analysis
  37. GRB050814: SWIFT/UVOT observation
  38. GRB050814: Refined analysis of the Swift-BAT burst
  39. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  40. GRB 050814: Swift XRT Afterglow Localization
  41. GRB 050814: Swift detection of a burst
  42. GRB 050813: Magellan detection of a high redshift galaxy cluster
  43. GRB050813, SDSS pre-burst observations
  44. GRB 050813: Swift-BAT refined analysis
  45. GRB 050813: Photometry of object in XRT error circle
  46. GRB050813: SWIFT/UVOT observation
  47. GRB 050813: Swift XRT afterglow localization
  48. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  49. Detection of an intermediate burst from SGR 1806-20 on August 8
  50. GRB050805b: CrAO optical limit
  51. GRB050803, optical observations
  52. Retraction of Swift Trigger 149131 (GRB 050805B)
  53. GRB 050805b: OHP optical limits
  54. GRB 050805b: TAROT optical limits
  55. GRB050805b: MASTER optical observations
  56. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  57. GRB050805a: MASTER optical candidat
  58. GRB050802: TNG optical observations
  59. GRB050803: Radio Observation
  60. GRB 050803: RTT150 optical observations
  61. GRB050801: Radio Observation
  62. GRB050730: Radio Detection
  63. GRB 050803: Keck Observations
  64. GRB 050803: Swift-BAT refined analysis
  65. GRB 050802.422: Fading of the afterglow and detection of the host
  66. GRB 050803: early Swift XRT analysis results
  67. GRB 050803: TAROT optical limits
  68. GCN GRB observation 050713A
  69. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  70. GRB050802 radio non-detection
  71. GRB 050730: OHP optical observations
  72. GRB 050802: early Swift XRT analysis results
  73. GRB 050802: Swift/UVOT observations
  74. GRB 050802: Swift-BAT refined analysis
  75. GRB050801: Optical photometry and decay index
  76. GRB 050802: Swift Gamma-ray Burst
  77. GRB050801: Swift/UVOT Optical and UV detections
  78. GRB 050730: Preliminary Analysis of MIKE Spectrum
  79. GCN 050801: early Swift XRT analysis results
  80. GRB 050801: Swift-BAT refined analysis
  81. GRB 050730: XRT refined analysis
  82. GRB 050730: early TAROT optical observations
  83. GRB 050730, spectra and optical photometry
  84. GRB050730: Refined BAT analysis of the Swift-BAT burst
  85. GRB 050730 XMM-Newton observation
  86. GRB050730: Swift-BAT detection of a weak burst
  87. GRB050713b: Maidanak optical observations
  88. GRB 050724: Secure Host Redshift from Keck
  89. GRB 050724: WHT optical observations
  90. GRB050713: analysis of the XMM-Newton observation
  91. Swift-BAT trigger 147918 is not a real GRB
  92. GRB050724: VLT observations of the variable source
  93. GRB050709: Second Epoch Chandra Observation
  94. GRB050726: Swift-BAT detection of a weak burst
  95. GRB 050724: Optical Variability in Nearby Galaxy
  96. GRB 050724: J-band observations
  97. GRB 050724: GMOS Imaging and Spectroscopy
  98. GRB050724: Radio Observation
  99. GRB 050724: Optical imaging/astrometry
  100. GRB 050724: Swift/UVOT Upper Limit

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