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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"

20258 results found.

  1. Swift Data Publicly Available Starting April 5, 2005
  2. Konus-Wind observation of GRB 050326
  3. GRB 050326: Early observations with Swift-UVOT
  4. GRB 050326 XMM-Newton observation
  5. GRB 050326: Swift XRT Position
  6. GRB 050326 BAT refined analysis
  7. GRB050326: delayed XRT observation
  8. Swift-BAT detection of a bright GRB 050326
  9. GRB050319: optical observation, March 20-22
  10. GRB050319: RTT150 Optical Observations
  11. GRB 050319: ROTSE-III Refined Analysis
  12. GRB050319: VLA Observations
  13. GRB050319: radio observation
  14. GRB 050319: Swift-UVOT detection of the afterglow
  15. GRB050319: Radio Observations
  16. GRB 050319: NIR afterglow candidate
  17. GRB 050319:Near IR afterglow
  18. GRB050319,optical observation
  19. GRB 050318: Swift/UVOT detection of afterglow emission
  20. RXTE Observations of GRB050318
  21. GRB050223: analysis of the XMM-Newton observation
  22. GRB050316: MASTER before, simultanious and follow up optical
  23. GRB 050306: ROTSE-III early limits
  24. GRB050316: MASTER optical observations
  25. GRB 050315: Swift-BAT further refined analysis
  26. GRB 050315 I-band observations
  27. GRB050315: Radio afterglow
  28. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  29. GRB 050315: Early Observations with Swift/UVOT
  30. GRB050223: No XMM-Newton OM detection of afterglow emission
  31. GRB 050306: Radio Observations
  32. GRB 050306: optical afterglow
  33. Swift-BAT trigger 107873: No Swift XRT counterpart
  34. GRB 050306: Confirmation of X-ray afterglow
  35. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  36. Swift 107873: P60 Optical Observations
  37. GRB 050306: CORRECTION to date of observation
  38. GRB 050306: R-band observations
  39. GRB 050306: No Swift UVOT Optical Counterpart Detected
  40. GRB 050306: REM optical-infrared observations
  41. GRB 050306: Possible X-ray Afterglow Position from the Swift
  42. Swift trigger 107518: optical observation
  43. GRB 050306: TAROT optical observations
  44. GRB 050306,optical observation
  45. GRB050215B: Late-Time Swift UVOT Observations
  46. PROMPT VRcIc Observations of GRB 050223
  47. XMM-Newton Images of GRB 050223
  48. GRB 050219b: candidate NIR afterglow
  49. GRB 050223: optical observations
  50. GRB050223 XMM-Newton observation
  51. GRB050223: ROTSE-III Optical Observations
  52. GRB 050223: Swift XRT Position
  53. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  54. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  55. GRB 050219a: Optical observations from LCO
  56. GRB 050219b: Optical and near-IR observations from LCO
  57. GRB 050219b: Swift-BAT detection of a burst
  58. GRB 050219a, optical observations
  59. GRB 050215b: XRT confirmation of IR afterglow candidate
  60. GRB050215b: P60 Optical Observations
  61. GRB 050215b: Swift XRT Source Variability
  62. GRB 050215b, BOOTES-2 simultaneous optical observations
  63. GRB 050215B: UKIRT K-band imaging
  64. GRB050215B: ROTSE-III optical observations
  65. GRB050215A: ROTSE-III Optical Observations
  66. GRB050209: TAROT optical observations
  67. GRB050209: REM optical observations
  68. GRB 050209 I-band observation
  69. GRB 050209 Optical observations
  70. GRB050209: P60 Optical Observations
  71. GRB 050209: Optical observation
  72. GRB 050128: Radio observations
  73. GRB050202: Radio Observations
  74. GRB 050202: Short burst detected by Swift-BAT
  75. GRB 050128 Optical observation with REM
  76. SGR1806-20: Swift-BAT detection of a large normal burst
  77. GRB 050128: near-infrared observations with REM
  78. GRB050128,optical observations
  79. GRB050126: Updated Swift XRT Position
  80. GRB 050126: Radio Observations
  81. GRB 050128: Swift XRT prompt afterglow position
  82. GRB050126: MASTER optical limit for KECK OT
  83. GRB050126: MASTER optical observations
  84. GRB 050126: Detection of NIR afterglow with Keck/NIRC
  85. GRB 050124 I-band observation
  86. GRB050124,optical observation
  87. GRB050124: Updated Swift XRT Position and Fluxes
  88. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  89. GRB050123,optical observation
  90. GRB 050123: KAIT observations
  91. GRB050117a: Refined analysis
  92. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  93. GRB050117: optical observation
  94. GRB050117: MASTER optical observations
  95. MASTER:GRB050117 SWIFT
  96. GRB050117: Swift XRT Position
  97. Triangulation of Short Hard GRB050112 (large error box)
  98. SGR1806-20: Swift-BAT observations of two additional bursts
  99. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  100. Further VLA observations of SGR 1806-20

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