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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"

27770 results found.

  1. GRB 050306: No Swift UVOT Optical Counterpart Detected
  2. GRB 050306: Possible X-ray Afterglow Position from the Swift
  3. Swift trigger 107518: optical observation
  4. GRB 050306,optical observation
  5. GRB 050306: Swift-BAT detection of a long burst
  6. GRB050215B: Late-Time Swift UVOT Observations
  7. PROMPT VRcIc Observations of GRB 050223
  8. GRB 050223: optical observations
  9. GRB050223 XMM-Newton observation
  10. INTEGRAL detection of GRB 050223
  11. GRB050223: No Swift UVOT Detection of Afterglow Emission
  12. GRB050223: ROTSE-III Optical Observations
  13. GRB 050223 Swift/BAT detection of a burst
  14. GRB 050223: Swift XRT Position
  15. GRB050219b: CORRECTION to time of UVOT observations
  16. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  17. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  18. GRB 050219b: CORRECTION to refined XRT position
  19. GRB 050219b: Optical and near-IR observations from LCO
  20. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  21. GRB 050219b: Refined XRT position
  22. GRB 050219b: Swift-BAT detection of a burst
  23. GRB 050219b: CORRECTION: Swift XRT Position
  24. GRB 050219b: Swift XRT Position
  25. GRB 050219a, optical observations
  26. GRB 050219a: Refined XRT position
  27. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  28. GRB 050219: Swift-BAT detection of a burst
  29. GRB050215b: Swift UVOT Detection of Afterglow Emission
  30. GRB 050219: Prompt X-ray position
  31. GRB 050215b: XRT confirmation of IR afterglow candidate
  32. GRB050215b: P60 Optical Observations
  33. GRB 050215b: Swift XRT Source Variability
  34. GRB 050215B: candidate afterglow
  35. GRB 050215b : Lulin follow-up observation
  36. GRB 050215b, BOOTES-2 simultaneous optical observations
  37. GRB 050215B: UKIRT K-band imaging
  38. GRB 050215b: Swift XRT Observations
  39. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  40. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  41. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  42. GRB050215B: ROTSE-III optical observations
  43. GRB050215A: ROTSE-III Optical Observations
  44. short/hard GRB 050202, optical observations
  45. GRB 050128: Radio observations
  46. Further analysis of the short Swift-BAT GRB 050202
  47. GRB 050202: Second epoch radio observations
  48. GRB050202: Radio Observations
  49. GRB 050202: Short burst detected by Swift-BAT
  50. SGR1806-20: Swift-BAT detection of a large normal burst
  51. GRB050128: Faulkes Telescope South observations
  52. GRB 050128: near-infrared observations with REM
  53. GRB050128,optical observations
  54. GRB050126: Updated Swift XRT Position
  55. SGR 1806-20: GMRT results at 240 MHz band.
  56. SGR 1806-20: low frequency GMRT results of 2005 Jan 16.
  57. GRB 050126: Radio Observations
  58. GRB050128 Swift-BAT observations
  59. GRB 050128: Swift XRT prompt afterglow position
  60. GRB 050124: K-band afterglow observations
  61. GRB050126: MASTER optical limit for KECK OT
  62. GRB050126: Burst Parameters Measured by BAT
  63. GRB050126: MASTER optical observations
  64. GRB 050126: Detection of NIR afterglow with Keck/NIRC
  65. GRB 050126: Prompt XRT detection and localization
  66. GRB050124: No Swift UVOT Detection of Afterglow Emission
  67. GRB 050124, SMARTS optical/IR observations
  68. GRB 050117a: Radio Observations
  69. GRB050124,optical observation
  70. GRB050124: Updated Swift XRT Position and Fluxes
  71. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  72. GRB050124: Refined BAT position, spectral and fluence information
  73. GRB050124: Swift-BAT position of a double-peaked burst
  74. CFHTLS optical transient unlikely to be a GRB
  75. GRB050117a: Radio Observations
  76. GRB050117a: Refined analysis
  77. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  78. GRB050117b: Swift-BAT detection of a weak burst
  79. GRB050117: optical observation
  80. GRB 050117, I-band observations
  81. GRB 050117: Optical observation
  82. GRB050117: Refined XRT position
  83. GRB050117: MASTER optical observations
  84. MASTER:GRB050117 SWIFT
  85. GRB050117: Swift-BAT detection of a long multi-peaked burst
  86. GRB050117: Swift XRT Position
  87. SGR 1806-20: Further low frequency GMRT results
  88. SGR1806-20: Swift-BAT observations of two additional bursts
  89. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  90. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  91. SGR 1806-20, RHESSI observations of the 041227 giant flare
  92. Second-epoch VLA observations of SGR 1806-20
  93. SGR1806: Detection of a Sudden Ionospheric Disturbance
  94. DETECTION OF POLARIZATION OF THE RADIO EMISSION FROM SGR 1806-20
  95. SGR1806 VLA Observations
  96. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  97. GRB 041217: Optical observations
  98. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  99. Detection of the SGR 1806-20 giant outburst back-scattered by the
  100. GRB041228: ROTSE-III Optical Observations

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