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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"

20356 results found.

  1. GRB 050319: Swift-UVOT detection of the afterglow
  2. GRB050319: Radio Observations
  3. GRB 050319: NIR afterglow candidate
  4. GRB 050319:Near IR afterglow
  5. GRB050319,optical observation
  6. GRB 050318: Swift/UVOT detection of afterglow emission
  7. RXTE Observations of GRB050318
  8. GRB050223: analysis of the XMM-Newton observation
  9. GRB050316: MASTER before, simultanious and follow up optical
  10. GRB 050306: ROTSE-III early limits
  11. GRB050316: MASTER optical observations
  12. GRB 050315 I-band observations
  13. GRB050315: Radio afterglow
  14. GRB 050315: Early Observations with Swift/UVOT
  15. GRB 050306: Radio Observations
  16. GRB 050306: optical afterglow
  17. Swift-BAT trigger 107873: No Swift XRT counterpart
  18. GRB 050306: Confirmation of X-ray afterglow
  19. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  20. Swift 107873: P60 Optical Observations
  21. GRB 050306: R-band observations
  22. GRB 050306: REM optical-infrared observations
  23. GRB 050306: Possible X-ray Afterglow Position from the Swift
  24. Swift trigger 107518: optical observation
  25. GRB 050306: TAROT optical observations
  26. GRB 050306,optical observation
  27. GRB050215B: Late-Time Swift UVOT Observations
  28. PROMPT VRcIc Observations of GRB 050223
  29. XMM-Newton Images of GRB 050223
  30. GRB 050219b: candidate NIR afterglow
  31. GRB 050223: optical observations
  32. GRB050223 XMM-Newton observation
  33. GRB050223: ROTSE-III Optical Observations
  34. GRB 050223 Swift/BAT detection of a burst
  35. GRB 050223: Swift XRT Position
  36. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  37. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  38. GRB 050219a: Optical observations from LCO
  39. GRB 050219b: Optical and near-IR observations from LCO
  40. GRB 050219b: Swift-BAT detection of a burst
  41. GRB 050219b: CORRECTION: Swift XRT Position
  42. GRB 050219b: Swift XRT Position
  43. GRB 050219a, optical observations
  44. GRB 050219: Swift-BAT detection of a burst
  45. GRB 050215b: XRT confirmation of IR afterglow candidate
  46. GRB050215b: P60 Optical Observations
  47. GRB 050215b: Swift XRT Source Variability
  48. GRB 050215b, BOOTES-2 simultaneous optical observations
  49. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  50. GRB050215A: ROTSE-III Optical Observations
  51. GRB050209: TAROT optical observations
  52. GRB050209: REM optical observations
  53. GRB 050209 I-band observation
  54. GRB 050209 Optical observations
  55. GRB050209: P60 Optical Observations
  56. GRB 050128: Radio observations
  57. Further analysis of the short Swift-BAT GRB 050202
  58. GRB 050202: Optical observations with LCO40
  59. GRB 050202: Short burst detected by Swift-BAT
  60. GRB 050128 Optical observation with REM
  61. GRB 050128: near-infrared observations with REM
  62. GRB050128,optical observations
  63. GRB050126: Updated Swift XRT Position
  64. GRB 050126: Radio Observations
  65. GRB 050128: Swift XRT prompt afterglow position
  66. GRB050126: MASTER optical limit for KECK OT
  67. GRB050126: Burst Parameters Measured by BAT
  68. GRB050126: MASTER optical observations
  69. GRB 050124 I-band observation
  70. GRB050124,optical observation
  71. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  72. GRB050124: Swift-BAT position of a double-peaked burst
  73. GRB050123,optical observation
  74. GRB 050123: KAIT observations
  75. CFHTLS optical transient unlikely to be a GRB
  76. GRB050117a: Radio Observations
  77. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  78. GRB050117: optical observation
  79. GRB050117: MASTER optical observations
  80. MASTER:GRB050117 SWIFT
  81. GRB050117: Swift-BAT detection of a long multi-peaked burst
  82. GRB050117: Swift XRT Position
  83. Triangulation of Short Hard GRB050112 (large error box)
  84. SGR 1806-20: Further low frequency GMRT results
  85. SGR1806-20: Swift-BAT observations of two additional bursts
  86. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  87. SGR 1806-20 and extragalactic short-duration GRBs
  88. Fourth Epoch VLA observations of SGR 1806-20
  89. SGR 1806-20, RHESSI observations of the 041227 giant flare
  90. Second-epoch VLA observations of SGR 1806-20
  91. SGR1806 VLA Observations
  92. GRB 041217: Optical observations
  93. GRB041219; RXTE ASM Observations
  94. GRB041226: Swift-BAT detection of a burst
  95. GRB041223: decay of the afterglow
  96. GRB 041224: near-infrared observations with REM
  97. GRB041223: optical and NIR observations with REM
  98. Swift-BAT Time History of GRB041219
  99. GRB 041219: TAROT optical observations
  100. GRB 041218: TAROT optical observations

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