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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"

32834 results found.

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

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