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

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