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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"

34039 results found.

  1. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  2. GRB050401: TNG R-band observation
  3. GRB 050402A: IR Analysis
  4. GRB 050402A: IR Observations
  5. GRB 050402: Early observations with Swift-UVOT
  6. Swift Trigger 113225: P60 Observations
  7. GRB 050401: Optical afterglow confirmed
  8. GRB 050401: Optical afterglow candidate
  9. Swift-BAT detection of GRB 050401
  10. GRB 050401: Prompt XRT position
  11. Retraction of three Swift GRB triggers
  12. GRB050331: No Afterglow Detected
  13. Swift-BAT detection of GRB 050331b
  14. GRB 050331: Swift UVOT Source
  15. Swift-BAT detection of GRB 050331
  16. GRB 050331: Swift XRT Position
  17. GRB050319: radio observation
  18. Konus-Wind observation of GRB 050326
  19. GRB 050326: Early observations with Swift-UVOT
  20. GRB 050326 XMM-Newton observation
  21. GRB 050326 : Planned XMM-Newton observation
  22. GRB 050326: Swift XRT Position
  23. GRB050326: optical limit 33min before GRB
  24. GRB 050326 BAT refined analysis
  25. GRB050326: delayed XRT observation
  26. Swift-BAT detection of a bright GRB 050326
  27. GRB050319, color indices
  28. GRB050319: RTT150 Optical Observations
  29. Swift-BAT trigger 112060 is not a real GRB
  30. GRB 050319: Absorption redshift from the Nordic Optical Telescope
  31. GRB 050319: ROTSE-III Refined Analysis
  32. GRB 050318: Swift-BAT refined analysis
  33. Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
  34. GRB050319: VLA Observations
  35. GRB 050319 R band observations
  36. GRB 050319: Swift-UVOT detection of the afterglow
  37. GRB 050315: Variability Analysis of Swift BAT Time History
  38. GRB050319: Radio Observations
  39. GRB 050319: NIR afterglow candidate
  40. GRB 050319:Near IR afterglow
  41. GRB 050318: SWIFT-UVOT refined analysis
  42. GRB 050318: Absorption redshift from Magellan
  43. GRB 050319: Optical observation
  44. GRB 050319 : Confirmation of optical afterglow decay
  45. GRB 050319: Swift-BAT refined analysis
  46. GRB050319,optical observation
  47. Swift Detection of GRB 050319
  48. GRB 050319: Detection of Possible Optical Counterpart
  49. GRB 050318: Swift/UVOT detection of afterglow emission
  50. GRB 050318: Magellan optical afterglow identification
  51. GRB050318: Swift XRT position
  52. RXTE Observations of GRB050318
  53. Swift-BAT detection of GRB 050318
  54. GRB 050315, SMARTS optical afterglow decay
  55. GRB050316: MASTER before, simultanious and follow up optical
  56. GRB 050306: ROTSE-III early limits
  57. GRB050316: MASTER optical observations
  58. GRB 050315: Swift-BAT further refined analysis
  59. GRB 050315, SMARTS optical/IR afterglow observations
  60. GRB 050315 I-band observations
  61. GRB050315: Radio afterglow
  62. GRB 050315: Absorption redshift
  63. GRB 050315: Optical afterglow identification
  64. GRB050315: Swift-BAT Refined analysis
  65. Non-detection of GRB050315 in ATCA Radio Observations
  66. GRB 050315: Swift XRT Position
  67. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  68. GRB 050315: Early Observations with Swift/UVOT
  69. Swift-BAT detection of GRB 050315
  70. GRB 050306: Radio Observations
  71. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  72. GRB050309: CONCAM pre-trigger and trigger coincident optical
  73. GRB 050306: optical afterglow
  74. GRB 050126: Redshift determination
  75. Swift-BAT trigger 107873: No Swift XRT counterpart
  76. GRB 050306: Confirmation of X-ray afterglow
  77. GRB 050309, Early optical limits from RAPTOR
  78. GRB 050306: further TAROT optical data
  79. GRB050309: Early optical limit from P60
  80. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  81. GRB 050309 : Lulin R-band observation
  82. Swift 107873: P60 Optical Observations
  83. GRB 050306: CORRECTION to date of observation
  84. GRB 050306: R-band observations
  85. GRB 050306: No Swift UVOT Optical Counterpart Detected
  86. GRB 050306: REM optical-infrared observations
  87. GRB 050306: Possible X-ray Afterglow Position from the Swift
  88. Swift trigger 107518: optical observation
  89. GRB 050306: TAROT optical observations
  90. GRB 050306,optical observation
  91. GRB 050306: Swift-BAT detection of a long burst
  92. GRB 050126: Confirmation of the NIR afterglow candidate
  93. PROMPT VRcIc Observations of GRB 050223
  94. XRF/GRB 050215B: Radio Observations
  95. XMM-Newton Images of GRB 050223
  96. GRB 050219b: candidate NIR afterglow
  97. IBAS GRB Alert #2321
  98. GRB 050223: optical observations
  99. INTEGRAL detection of GRB 050223
  100. GRB 050223 : Planned XMM-Newton observation

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