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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"

35957 results found.

  1. Swift-BAT detection of GRB 050315
  2. GRB 050306: Radio Observations
  3. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  4. GRB050309: CONCAM pre-trigger and trigger coincident optical
  5. GRB 050306: optical afterglow
  6. GRB 050126: Redshift determination
  7. Swift-BAT trigger 107873: No Swift XRT counterpart
  8. GRB 050306: Confirmation of X-ray afterglow
  9. GRB 050309, Early optical limits from RAPTOR
  10. GRB 050306: further TAROT optical data
  11. GRB050309: Early optical limit from P60
  12. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  13. GRB 050309 : Lulin R-band observation
  14. Swift 107873: P60 Optical Observations
  15. GRB 050306: CORRECTION to date of observation
  16. GRB 050306: R-band observations
  17. GRB 050306: No Swift UVOT Optical Counterpart Detected
  18. GRB 050306: REM optical-infrared observations
  19. GRB 050306: Possible X-ray Afterglow Position from the Swift
  20. Swift trigger 107518: optical observation
  21. GRB 050306: TAROT optical observations
  22. GRB 050306,optical observation
  23. GRB 050306: Swift-BAT detection of a long burst
  24. GRB 050126: Confirmation of the NIR afterglow candidate
  25. PROMPT VRcIc Observations of GRB 050223
  26. XRF/GRB 050215B: Radio Observations
  27. XMM-Newton Images of GRB 050223
  28. GRB 050219b: candidate NIR afterglow
  29. IBAS GRB Alert #2321
  30. GRB 050223: optical observations
  31. INTEGRAL detection of GRB 050223
  32. GRB 050223 : Planned XMM-Newton observation
  33. GRB050223: ROTSE-III Optical Observations
  34. GRB 050223 Swift/BAT detection of a burst
  35. GRB 050223: Swift XRT Position
  36. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  37. GRB 050219b: CORRECTION to refined XRT position
  38. GRB 050219a: Optical observations from LCO
  39. GRB 050219b: Optical and near-IR observations from LCO
  40. GRB 050219b: Refined XRT position
  41. GRB 050219b: Swift-BAT detection of a burst
  42. GRB 050219b: CORRECTION: Swift XRT Position
  43. GRB 050219b: Swift XRT Position
  44. GRB 050219a, optical observations
  45. GRB 050219a: Refined XRT position
  46. GRB 050219: Swift-BAT detection of a burst
  47. GRB050215b: Swift UVOT Detection of Afterglow Emission
  48. GRB 050219: Prompt X-ray position
  49. GRB 050215B: Radio Observations
  50. GRB 050215b: XRT confirmation of IR afterglow candidate
  51. GRB050215b: P60 Optical Observations
  52. GRB 050215b: Swift XRT Source Variability
  53. GRB 050215B: candidate afterglow
  54. GRB 050215b : Lulin follow-up observation
  55. GRB 050215b, BOOTES-2 simultaneous optical observations
  56. GRB 050215B: UKIRT K-band imaging
  57. GRB 050215b: Swift XRT Observations
  58. GRB 050215b, BOOTES-1B optical limit
  59. GRB050215A: ROTSE-III Optical Observations
  60. GRB050209: TAROT optical observations
  61. GRB 050209(=U11568): Duration and spectrum
  62. short/hard GRB 050202, optical observations
  63. GRB050209: REM optical observations
  64. GRB 050209 I-band observation
  65. GRB 050209 Optical observations
  66. GRB050209: P60 Optical Observations
  67. GRB050209 (=U11568): A Long GRB Detected by HETE
  68. GRB 050209: Optical observation
  69. GRB 050128: Radio observations
  70. Further analysis of the short Swift-BAT GRB 050202
  71. GRB 050202: Second epoch radio observations
  72. GRB 050129: Optical observations
  73. GRB050202: Radio Observations
  74. GRB 050202: Optical observations with LCO40
  75. GRB 050202: Short burst detected by Swift-BAT
  76. GRB 050128 Optical observation with REM
  77. GRB 050129: a weak long GRB detected with INTEGRAL
  78. GRB050128: Faulkes Telescope South observations
  79. GRB 050124: Radio Observations
  80. GRB 050128: near-infrared observations with REM
  81. GRB050128,optical observations
  82. GRB 050126: A NIR afterglow candidate in the revised XRT error circle
  83. GRB 050126: Radio Observations
  84. GRB050128 Swift-BAT observations
  85. GRB 050128: Swift XRT prompt afterglow position
  86. GRB 050124: K-band afterglow observations
  87. GRB050126: MASTER optical limit for KECK OT
  88. GRB050126: MASTER optical observations
  89. GRB 050126: Detection of NIR afterglow with Keck/NIRC
  90. GRB 050126: Prompt XRT detection and localization
  91. GRB 050124: NIR afterglow confirmed with Keck/NIRC
  92. GRB 050124, SMARTS optical/IR observations
  93. GRB 050117a: Radio Observations
  94. GRB 050124 I-band observation
  95. GRB 050124: NIR Candidates from Keck/NIRC
  96. GRB050124,optical observation
  97. GRB 050124 : Lulin R-band follow-up observation
  98. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  99. GRB 050123 : I-band follow-up observation
  100. GRB050123: optical limit 1.8h before GRB

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