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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"
  1. GRB050315: Swift-BAT Refined analysis
  2. Non-detection of GRB050315 in ATCA Radio Observations
  3. GRB 050315: Swift XRT Position
  4. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  5. GRB 050315: Early Observations with Swift/UVOT
  6. Swift-BAT detection of GRB 050315
  7. GRB050223: No XMM-Newton OM detection of afterglow emission
  8. GRB 050306: Radio Observations
  9. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  10. GRB050309: CONCAM pre-trigger and trigger coincident optical
  11. GRB 050306: optical afterglow
  12. GRB 050126: Redshift determination
  13. Swift-BAT trigger 107873: No Swift XRT counterpart
  14. GRB 050306: Confirmation of X-ray afterglow
  15. GRB 050309, Early optical limits from RAPTOR
  16. GRB 050306: further TAROT optical data
  17. GRB050309: Early optical limit from P60
  18. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  19. GRB 050309 : Lulin R-band observation
  20. Swift 107873: P60 Optical Observations
  21. GRB 050306: CORRECTION to date of observation
  22. GRB 050306: R-band observations
  23. GRB 050306: No Swift UVOT Optical Counterpart Detected
  24. GRB 050306: REM optical-infrared observations
  25. GRB 050306: Possible X-ray Afterglow Position from the Swift
  26. Swift trigger 107518: optical observation
  27. GRB 050306: TAROT optical observations
  28. GRB 050306,optical observation
  29. GRB 050306: Swift-BAT detection of a long burst
  30. Ongoing activity of SGR 1806-20 after the giant flare
  31. GRB050215B: Late-Time Swift UVOT Observations
  32. GRB 050126: Confirmation of the NIR afterglow candidate
  33. PROMPT VRcIc Observations of GRB 050223
  34. XRF/GRB 050215B: Radio Observations
  35. XMM-Newton Images of GRB 050223
  36. GRB 050219b: candidate NIR afterglow
  37. IBAS GRB Alert #2321
  38. Confirmed XRF nature for GRB050215b
  39. GRB 050223: optical observations
  40. GRB050223 XMM-Newton observation
  41. INTEGRAL detection of GRB 050223
  42. GRB 050223 : Planned XMM-Newton observation
  43. GRB050223: No Swift UVOT Detection of Afterglow Emission
  44. GRB050223: ROTSE-III Optical Observations
  45. GRB 050223 Swift/BAT detection of a burst
  46. GRB 050223: Swift XRT Position
  47. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  48. GRB050219b: CORRECTION to time of UVOT observations
  49. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  50. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  51. GRB 050219b: CORRECTION to refined XRT position
  52. GRB 050219a: Optical observations from LCO
  53. GRB 050219b: Optical and near-IR observations from LCO
  54. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  55. GRB 050219b: Refined XRT position
  56. GRB 050219b: Swift-BAT detection of a burst
  57. GRB 050219b: CORRECTION: Swift XRT Position
  58. GRB 050219b: Swift XRT Position
  59. GRB 050219a, optical observations
  60. GRB 050219a: Refined XRT position
  61. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  62. GRB 050219: Swift-BAT detection of a burst
  63. GRB050215b: Swift UVOT Detection of Afterglow Emission
  64. GRB 050219: Prompt X-ray position
  65. GRB 050215B: Radio Observations
  66. GRB 050215b: XRT confirmation of IR afterglow candidate
  67. GRB050215b: P60 Optical Observations
  68. GRB 050215b: Swift XRT Source Variability
  69. GRB 050215B: candidate afterglow
  70. GRB 050215b : Lulin follow-up observation
  71. GRB 050215b, BOOTES-2 simultaneous optical observations
  72. GRB 050215B: UKIRT K-band imaging
  73. GRB 050215b: Swift XRT Observations
  74. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  75. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  76. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  77. GRB 050215b, BOOTES-1B optical limit
  78. GRB050215B: ROTSE-III optical observations
  79. GRB050215A: ROTSE-III Optical Observations
  80. GRB050209: TAROT optical observations
  81. GRB 050209(=U11568): Duration and spectrum
  82. short/hard GRB 050202, optical observations
  83. GRB050209: REM optical observations
  84. GRB 050209 I-band observation
  85. GRB 050209 Optical observations
  86. GRB050209: P60 Optical Observations
  87. GRB050209 (=U11568): A Long GRB Detected by HETE
  88. GRB 050209: Optical observation
  89. GRB 050128: Radio observations
  90. Further analysis of the short Swift-BAT GRB 050202
  91. GRB 050202: Second epoch radio observations
  92. GRB 050129: Optical observations
  93. GRB050202: Radio Observations
  94. GRB 050202: Optical observations with LCO40
  95. GRB 050202: Short burst detected by Swift-BAT
  96. GRB 050128 Optical observation with REM
  97. GRB 050129: a weak long GRB detected with INTEGRAL
  98. SGR1806-20: Swift-BAT detection of a large normal burst
  99. GRB050128: Faulkes Telescope South observations
  100. GRB 050124: Radio Observations

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