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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"

20363 results found.

  1. GRB 050326 XMM-Newton observation
  2. GRB 050326: Swift XRT Position
  3. GRB050326: delayed XRT observation
  4. GRB050319: optical observation, March 20-22
  5. GRB050319: RTT150 Optical Observations
  6. GRB050319: VLA Observations
  7. GRB050319: radio observation
  8. GRB 050319: Swift-UVOT detection of the afterglow
  9. GRB050319: Radio Observations
  10. GRB 050319: NIR afterglow candidate
  11. GRB 050319:Near IR afterglow
  12. GRB050319,optical observation
  13. GRB 050318: Swift/UVOT detection of afterglow emission
  14. RXTE Observations of GRB050318
  15. GRB050223: analysis of the XMM-Newton observation
  16. GRB050316: MASTER before, simultanious and follow up optical
  17. GRB 050306: ROTSE-III early limits
  18. GRB050316: MASTER optical observations
  19. GRB 050315 I-band observations
  20. GRB050315: Radio afterglow
  21. GRB 050315: Early Observations with Swift/UVOT
  22. GRB 050306: Radio Observations
  23. GRB 050306: optical afterglow
  24. Swift-BAT trigger 107873: No Swift XRT counterpart
  25. GRB 050306: Confirmation of X-ray afterglow
  26. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  27. Swift 107873: P60 Optical Observations
  28. GRB 050306: R-band observations
  29. GRB 050306: REM optical-infrared observations
  30. GRB 050306: Possible X-ray Afterglow Position from the Swift
  31. Swift trigger 107518: optical observation
  32. GRB 050306: TAROT optical observations
  33. GRB 050306,optical observation
  34. GRB050215B: Late-Time Swift UVOT Observations
  35. PROMPT VRcIc Observations of GRB 050223
  36. XMM-Newton Images of GRB 050223
  37. GRB 050219b: candidate NIR afterglow
  38. GRB 050223: optical observations
  39. GRB050223 XMM-Newton observation
  40. GRB050223: ROTSE-III Optical Observations
  41. GRB 050223 Swift/BAT detection of a burst
  42. GRB 050223: Swift XRT Position
  43. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  44. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  45. GRB 050219a: Optical observations from LCO
  46. GRB 050219b: Optical and near-IR observations from LCO
  47. GRB 050219b: Swift-BAT detection of a burst
  48. GRB 050219b: CORRECTION: Swift XRT Position
  49. GRB 050219b: Swift XRT Position
  50. GRB 050219a, optical observations
  51. GRB 050219: Swift-BAT detection of a burst
  52. GRB 050215b: XRT confirmation of IR afterglow candidate
  53. GRB050215b: P60 Optical Observations
  54. GRB 050215b: Swift XRT Source Variability
  55. GRB 050215b, BOOTES-2 simultaneous optical observations
  56. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  57. GRB050215A: ROTSE-III Optical Observations
  58. GRB050209: TAROT optical observations
  59. GRB050209: REM optical observations
  60. GRB 050209 I-band observation
  61. GRB 050209 Optical observations
  62. GRB050209: P60 Optical Observations
  63. GRB 050128: Radio observations
  64. Further analysis of the short Swift-BAT GRB 050202
  65. GRB 050202: Optical observations with LCO40
  66. GRB 050202: Short burst detected by Swift-BAT
  67. GRB 050128 Optical observation with REM
  68. GRB 050128: near-infrared observations with REM
  69. GRB050128,optical observations
  70. GRB050126: Updated Swift XRT Position
  71. GRB 050126: Radio Observations
  72. GRB 050128: Swift XRT prompt afterglow position
  73. GRB050126: MASTER optical limit for KECK OT
  74. GRB050126: Burst Parameters Measured by BAT
  75. GRB050126: MASTER optical observations
  76. GRB 050124 I-band observation
  77. GRB050124,optical observation
  78. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  79. GRB050124: Swift-BAT position of a double-peaked burst
  80. GRB050123,optical observation
  81. GRB 050123: KAIT observations
  82. CFHTLS optical transient unlikely to be a GRB
  83. GRB050117a: Radio Observations
  84. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  85. GRB050117: optical observation
  86. GRB050117: MASTER optical observations
  87. MASTER:GRB050117 SWIFT
  88. GRB050117: Swift-BAT detection of a long multi-peaked burst
  89. GRB050117: Swift XRT Position
  90. Triangulation of Short Hard GRB050112 (large error box)
  91. SGR 1806-20: Further low frequency GMRT results
  92. SGR1806-20: Swift-BAT observations of two additional bursts
  93. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  94. SGR 1806-20 and extragalactic short-duration GRBs
  95. Fourth Epoch VLA observations of SGR 1806-20
  96. SGR 1806-20, RHESSI observations of the 041227 giant flare
  97. Second-epoch VLA observations of SGR 1806-20
  98. SGR1806 VLA Observations
  99. GRB 041217: Optical observations
  100. GRB041219; RXTE ASM Observations

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