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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"

20951 results found.

  1. GRB050408: MASTER optical observations
  2. GRB050401: Radio Detection
  3. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  4. GRB 050406: Magellan optical observations
  5. GRB 050406: Early observations with Swift-UVOT
  6. GRB050401: Radio observation at 610 MHz with GMRT
  7. GRB050401, radio observation at 4.8 GHz and 8.64 GHz
  8. GRB 050401 Optical Observations
  9. GRB050401: TNG R-band observation
  10. GRB 050402A: IR Observations
  11. GRB 050402: Early observations with Swift-UVOT
  12. Swift Trigger 113225: P60 Observations
  13. GRB 050401: Optical afterglow confirmed
  14. GRB 050401: Optical afterglow candidate
  15. GRB050331: No Afterglow Detected
  16. GRB 050331: Swift UVOT Source
  17. GRB050319: radio observation
  18. GRB 050326: Early observations with Swift-UVOT
  19. GRB 050326: Swift XRT Position
  20. GRB050326: delayed XRT observation
  21. GRB050319, optical observations
  22. GRB050319, color indices
  23. GRB050319: optical observation, March 20-22
  24. GRB050319: RTT150 Optical Observations
  25. GRB 050319: ROTSE-III Refined Analysis
  26. GRB 050318: Swift-BAT refined analysis
  27. GRB050319: VLA Observations
  28. GRB 050319 R band observations
  29. GRB 050319: Swift-UVOT detection of the afterglow
  30. GRB050319: Radio Observations
  31. GRB 050319: NIR afterglow candidate
  32. GRB 050319:Near IR afterglow
  33. GRB 050318: Absorption redshift from Magellan
  34. GRB 050319 : Confirmation of optical afterglow decay
  35. GRB 050319: Detection of Possible Optical Counterpart
  36. GRB 050318: Swift/UVOT detection of afterglow emission
  37. GRB 050318: Magellan optical afterglow identification
  38. RXTE Observations of GRB050318
  39. GRB 050315, SMARTS optical afterglow decay
  40. GRB050316: MASTER before, simultanious and follow up optical
  41. GRB050316: MASTER optical observations
  42. GRB 050315: Swift-BAT further refined analysis
  43. GRB 050315, SMARTS optical/IR afterglow observations
  44. GRB 050315 I-band observations
  45. GRB050315: Radio afterglow
  46. GRB 050315: Absorption redshift
  47. GRB 050315: Optical afterglow identification
  48. Non-detection of GRB050315 in ATCA Radio Observations
  49. GRB 050315: Swift XRT Position
  50. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  51. GRB 050315: Early Observations with Swift/UVOT
  52. Swift-BAT detection of GRB 050315
  53. GRB050223: No XMM-Newton OM detection of afterglow emission
  54. GRB 050306: Radio Observations
  55. GRB 050306: optical afterglow
  56. Swift-BAT trigger 107873: No Swift XRT counterpart
  57. GRB050309: Early optical limit from P60
  58. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  59. Swift 107873: P60 Optical Observations
  60. GRB 050306: CORRECTION to date of observation
  61. GRB 050306: R-band observations
  62. GRB 050306: No Swift UVOT Optical Counterpart Detected
  63. GRB 050306: REM optical-infrared observations
  64. GRB 050306: Possible X-ray Afterglow Position from the Swift
  65. GRB 050306: TAROT optical observations
  66. GRB050215B: Late-Time Swift UVOT Observations
  67. PROMPT VRcIc Observations of GRB 050223
  68. XRF/GRB 050215B: Radio Observations
  69. GRB 050219b: candidate NIR afterglow
  70. GRB 050223: optical observations
  71. GRB050223: No Swift UVOT Detection of Afterglow Emission
  72. GRB050223: ROTSE-III Optical Observations
  73. GRB 050223: Swift XRT Position
  74. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  75. GRB050219b: CORRECTION to time of UVOT observations
  76. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  77. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  78. GRB 050219a: Optical observations from LCO
  79. GRB 050219b: Optical and near-IR observations from LCO
  80. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  81. GRB 050219b: CORRECTION: Swift XRT Position
  82. GRB 050219b: Swift XRT Position
  83. GRB 050219a, optical observations
  84. GRB 050219a: Refined XRT position
  85. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  86. GRB050215b: Swift UVOT Detection of Afterglow Emission
  87. GRB 050215B: Radio Observations
  88. GRB 050215b: XRT confirmation of IR afterglow candidate
  89. GRB050215b: P60 Optical Observations
  90. GRB 050215b: Swift XRT Source Variability
  91. GRB 050215b : Lulin follow-up observation
  92. GRB 050215b, BOOTES-2 simultaneous optical observations
  93. GRB 050215b: Swift XRT Observations
  94. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  95. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  96. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  97. GRB050215B: ROTSE-III optical observations
  98. GRB050215A: ROTSE-III Optical Observations
  99. GRB050209: TAROT optical observations
  100. short/hard GRB 050202, optical observations

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