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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"

20357 results found.

  1. GRB050319: radio observation
  2. GRB 050319: Swift-UVOT detection of the afterglow
  3. GRB050319: Radio Observations
  4. GRB 050319: NIR afterglow candidate
  5. GRB 050319:Near IR afterglow
  6. GRB050319,optical observation
  7. GRB 050318: Swift/UVOT detection of afterglow emission
  8. RXTE Observations of GRB050318
  9. GRB050223: analysis of the XMM-Newton observation
  10. GRB050316: MASTER before, simultanious and follow up optical
  11. GRB 050306: ROTSE-III early limits
  12. GRB050316: MASTER optical observations
  13. GRB 050315 I-band observations
  14. GRB050315: Radio afterglow
  15. GRB 050315: Early Observations with Swift/UVOT
  16. GRB 050306: Radio Observations
  17. GRB 050306: optical afterglow
  18. Swift-BAT trigger 107873: No Swift XRT counterpart
  19. GRB 050306: Confirmation of X-ray afterglow
  20. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  21. Swift 107873: P60 Optical Observations
  22. GRB 050306: R-band observations
  23. GRB 050306: REM optical-infrared observations
  24. GRB 050306: Possible X-ray Afterglow Position from the Swift
  25. Swift trigger 107518: optical observation
  26. GRB 050306: TAROT optical observations
  27. GRB 050306,optical observation
  28. GRB050215B: Late-Time Swift UVOT Observations
  29. PROMPT VRcIc Observations of GRB 050223
  30. XMM-Newton Images of GRB 050223
  31. GRB 050219b: candidate NIR afterglow
  32. GRB 050223: optical observations
  33. GRB050223 XMM-Newton observation
  34. GRB050223: ROTSE-III Optical Observations
  35. GRB 050223 Swift/BAT detection of a burst
  36. GRB 050223: Swift XRT Position
  37. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  38. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  39. GRB 050219a: Optical observations from LCO
  40. GRB 050219b: Optical and near-IR observations from LCO
  41. GRB 050219b: Swift-BAT detection of a burst
  42. GRB 050219b: CORRECTION: Swift XRT Position
  43. GRB 050219b: Swift XRT Position
  44. GRB 050219a, optical observations
  45. GRB 050219: Swift-BAT detection of a burst
  46. GRB 050215b: XRT confirmation of IR afterglow candidate
  47. GRB050215b: P60 Optical Observations
  48. GRB 050215b: Swift XRT Source Variability
  49. GRB 050215b, BOOTES-2 simultaneous optical observations
  50. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  51. GRB050215A: ROTSE-III Optical Observations
  52. GRB050209: TAROT optical observations
  53. GRB050209: REM optical observations
  54. GRB 050209 I-band observation
  55. GRB 050209 Optical observations
  56. GRB050209: P60 Optical Observations
  57. GRB 050128: Radio observations
  58. Further analysis of the short Swift-BAT GRB 050202
  59. GRB 050202: Optical observations with LCO40
  60. GRB 050202: Short burst detected by Swift-BAT
  61. GRB 050128 Optical observation with REM
  62. GRB 050128: near-infrared observations with REM
  63. GRB050128,optical observations
  64. GRB050126: Updated Swift XRT Position
  65. GRB 050126: Radio Observations
  66. GRB 050128: Swift XRT prompt afterglow position
  67. GRB050126: MASTER optical limit for KECK OT
  68. GRB050126: Burst Parameters Measured by BAT
  69. GRB050126: MASTER optical observations
  70. GRB 050124 I-band observation
  71. GRB050124,optical observation
  72. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  73. GRB050124: Swift-BAT position of a double-peaked burst
  74. GRB050123,optical observation
  75. GRB 050123: KAIT observations
  76. CFHTLS optical transient unlikely to be a GRB
  77. GRB050117a: Radio Observations
  78. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  79. GRB050117: optical observation
  80. GRB050117: MASTER optical observations
  81. MASTER:GRB050117 SWIFT
  82. GRB050117: Swift-BAT detection of a long multi-peaked burst
  83. GRB050117: Swift XRT Position
  84. Triangulation of Short Hard GRB050112 (large error box)
  85. SGR 1806-20: Further low frequency GMRT results
  86. SGR1806-20: Swift-BAT observations of two additional bursts
  87. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  88. SGR 1806-20 and extragalactic short-duration GRBs
  89. Fourth Epoch VLA observations of SGR 1806-20
  90. SGR 1806-20, RHESSI observations of the 041227 giant flare
  91. Second-epoch VLA observations of SGR 1806-20
  92. SGR1806 VLA Observations
  93. GRB 041217: Optical observations
  94. GRB041219; RXTE ASM Observations
  95. GRB041226: Swift-BAT detection of a burst
  96. GRB041223: decay of the afterglow
  97. GRB 041224: near-infrared observations with REM
  98. GRB041223: optical and NIR observations with REM
  99. Swift-BAT Time History of GRB041219
  100. GRB 041219: TAROT optical observations

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