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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"

15716 results found.

  1. GRB 050406: Early observations with Swift-UVOT
  2. Swift-BAT detection of GRB 050406
  3. GRB050401: Radio observation at 610 MHz with GMRT
  4. GRB 050401: VLT spectroscopic redshift
  5. GRB 050401 Optical Observations
  6. GRB050401: Maidanak optical observation
  7. GRB 050401 BAT refined analysis
  8. GRB050401: TNG R-band observation
  9. GRB 050402: Early observations with Swift-UVOT
  10. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  11. GRB 050401: Optical afterglow confirmed
  12. GRB 050401: Optical afterglow candidate
  13. GRB050331: No Afterglow Detected
  14. GRB 050331: Swift UVOT Source
  15. GRB050326: optical limit
  16. GRB 050326: Early observations with Swift-UVOT
  17. GRB050326: optical limit 33min before GRB
  18. GRB050319, optical observations
  19. GRB050319, color indices
  20. GRB050319: optical observation, March 20-22
  21. GRB050319: RTT150 Optical Observations
  22. GRB 050319: Absorption redshift from the Nordic Optical Telescope
  23. GRB 050318: Swift-BAT refined analysis
  24. Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
  25. GRB050319: VLA Observations
  26. GRB050319: radio observation
  27. GRB 050319 R band observations
  28. GRB 050319: Swift-UVOT detection of the afterglow
  29. GRB050319: Radio Observations
  30. GRB 050319: NIR afterglow candidate
  31. GRB 050319:Near IR afterglow
  32. GRB050319: BR optical photometry
  33. GRB 050319: Optical observation
  34. GRB 050319 : Confirmation of optical afterglow decay
  35. GRB050319,optical observation
  36. GRB 050319: Detection of Possible Optical Counterpart
  37. GRB 050318: Swift/UVOT detection of afterglow emission
  38. GRB 050318: Magellan optical afterglow identification
  39. GRB 050315, SMARTS optical afterglow decay
  40. GRB050223: analysis of the XMM-Newton observation
  41. GRB050316: MASTER before, simultanious and follow up optical
  42. GRB 050306: ROTSE-III early limits
  43. GRB050316: MASTER optical observations
  44. GRB 050315: Swift-BAT further refined analysis
  45. GRB 050315, SMARTS optical/IR afterglow observations
  46. GRB 050315 I-band observations
  47. GRB050315: Radio afterglow
  48. GRB 050315: Optical afterglow identification
  49. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  50. GRB 050315: Early Observations with Swift/UVOT
  51. GRB050223: No XMM-Newton OM detection of afterglow emission
  52. GRB 050306: Radio Observations
  53. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  54. GRB050309: CONCAM pre-trigger and trigger coincident optical
  55. GRB 050306: optical afterglow
  56. GRB 050309, Early optical limits from RAPTOR
  57. GRB 050306: further TAROT optical data
  58. GRB050309: Early optical limit from P60
  59. Swift 107873: P60 Optical Observations
  60. GRB 050306: CORRECTION to date of observation
  61. GRB 050306: No Swift UVOT Optical Counterpart Detected
  62. GRB 050306: REM optical-infrared observations
  63. Swift trigger 107518: optical observation
  64. GRB 050306: TAROT optical observations
  65. GRB 050306,optical observation
  66. GRB050215B: Late-Time Swift UVOT Observations
  67. PROMPT VRcIc Observations of GRB 050223
  68. GRB 050219b: candidate NIR afterglow
  69. GRB 050223: optical observations
  70. GRB050223: No Swift UVOT Detection of Afterglow Emission
  71. GRB050223: ROTSE-III Optical Observations
  72. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  73. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  74. GRB 050219a: Optical observations from LCO
  75. GRB 050219b: Optical and near-IR observations from LCO
  76. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  77. GRB 050219a, optical observations
  78. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  79. GRB050215b: Swift UVOT Detection of Afterglow Emission
  80. GRB 050215B: Radio Observations
  81. GRB 050215b: XRT confirmation of IR afterglow candidate
  82. GRB050215b: P60 Optical Observations
  83. GRB 050215b: Swift XRT Source Variability
  84. GRB 050215b, BOOTES-2 simultaneous optical observations
  85. GRB 050215b: Swift XRT Observations
  86. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  87. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  88. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  89. GRB 050215b, BOOTES-1B optical limit
  90. GRB050215B: ROTSE-III optical observations
  91. GRB050215A: ROTSE-III Optical Observations
  92. GRB050209: TAROT optical observations
  93. GRB 050209(=U11568): Duration and spectrum
  94. short/hard GRB 050202, optical observations
  95. GRB050209: REM optical observations
  96. GRB 050209 Optical observations
  97. GRB050209: P60 Optical Observations
  98. GRB050209 (=U11568): A Long GRB Detected by HETE
  99. GRB 050209: Optical observation
  100. Further analysis of the short Swift-BAT GRB 050202

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