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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. GRB050319: BR optical photometry
  2. GRB 050318: SWIFT-UVOT refined analysis
  3. GRB 050318: Absorption redshift from Magellan
  4. GRB 050319: Optical observation
  5. GRB 050319 : Confirmation of optical afterglow decay
  6. GRB 050319: Swift-BAT refined analysis
  7. GRB050319,optical observation
  8. Swift Detection of GRB 050319
  9. GRB 050319: Detection of Possible Optical Counterpart
  10. GRB 050318: Swift/UVOT detection of afterglow emission
  11. GRB 050318: Magellan optical afterglow identification
  12. GRB050318: Swift XRT position
  13. RXTE Observations of GRB050318
  14. Swift-BAT detection of GRB 050318
  15. GRB 050315, SMARTS optical afterglow decay
  16. GRB050223: analysis of the XMM-Newton observation
  17. GRB050316: MASTER before, simultanious and follow up optical
  18. GRB 050306: ROTSE-III early limits
  19. GRB050316: MASTER optical observations
  20. GRB 050315: Swift-BAT further refined analysis
  21. GRB 050315, SMARTS optical/IR afterglow observations
  22. GRB 050315 I-band observations
  23. GRB050315: Radio afterglow
  24. GRB 050315: Absorption redshift
  25. GRB 050315: Optical afterglow identification
  26. GRB050315: Swift-BAT Refined analysis
  27. Non-detection of GRB050315 in ATCA Radio Observations
  28. GRB 050315: Swift XRT Position
  29. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  30. GRB 050315: Early Observations with Swift/UVOT
  31. Swift-BAT detection of GRB 050315
  32. GRB050223: No XMM-Newton OM detection of afterglow emission
  33. GRB 050306: Radio Observations
  34. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  35. GRB050309: CONCAM pre-trigger and trigger coincident optical
  36. GRB 050306: optical afterglow
  37. GRB 050126: Redshift determination
  38. Swift-BAT trigger 107873: No Swift XRT counterpart
  39. GRB 050306: Confirmation of X-ray afterglow
  40. GRB 050309, Early optical limits from RAPTOR
  41. GRB 050306: further TAROT optical data
  42. GRB050309: Early optical limit from P60
  43. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  44. GRB 050309 : Lulin R-band observation
  45. Swift 107873: P60 Optical Observations
  46. GRB 050306: CORRECTION to date of observation
  47. GRB 050306: R-band observations
  48. GRB 050306: No Swift UVOT Optical Counterpart Detected
  49. GRB 050306: REM optical-infrared observations
  50. GRB 050306: Possible X-ray Afterglow Position from the Swift
  51. Swift trigger 107518: optical observation
  52. GRB 050306: TAROT optical observations
  53. GRB 050306,optical observation
  54. GRB 050306: Swift-BAT detection of a long burst
  55. Ongoing activity of SGR 1806-20 after the giant flare
  56. GRB050215B: Late-Time Swift UVOT Observations
  57. GRB 050126: Confirmation of the NIR afterglow candidate
  58. PROMPT VRcIc Observations of GRB 050223
  59. XRF/GRB 050215B: Radio Observations
  60. XMM-Newton Images of GRB 050223
  61. GRB 050219b: candidate NIR afterglow
  62. IBAS GRB Alert #2321
  63. Confirmed XRF nature for GRB050215b
  64. GRB 050223: optical observations
  65. GRB050223 XMM-Newton observation
  66. INTEGRAL detection of GRB 050223
  67. GRB 050223 : Planned XMM-Newton observation
  68. GRB050223: No Swift UVOT Detection of Afterglow Emission
  69. GRB050223: ROTSE-III Optical Observations
  70. GRB 050223 Swift/BAT detection of a burst
  71. GRB 050223: Swift XRT Position
  72. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  73. GRB050219b: CORRECTION to time of UVOT observations
  74. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  75. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  76. GRB 050219b: CORRECTION to refined XRT position
  77. GRB 050219a: Optical observations from LCO
  78. GRB 050219b: Optical and near-IR observations from LCO
  79. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  80. GRB 050219b: Refined XRT position
  81. GRB 050219b: Swift-BAT detection of a burst
  82. GRB 050219b: CORRECTION: Swift XRT Position
  83. GRB 050219b: Swift XRT Position
  84. GRB 050219a, optical observations
  85. GRB 050219a: Refined XRT position
  86. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  87. GRB 050219: Swift-BAT detection of a burst
  88. GRB050215b: Swift UVOT Detection of Afterglow Emission
  89. GRB 050219: Prompt X-ray position
  90. GRB 050215B: Radio Observations
  91. GRB 050215b: XRT confirmation of IR afterglow candidate
  92. GRB050215b: P60 Optical Observations
  93. GRB 050215b: Swift XRT Source Variability
  94. GRB 050215B: candidate afterglow
  95. GRB 050215b : Lulin follow-up observation
  96. GRB 050215b, BOOTES-2 simultaneous optical observations
  97. GRB 050215B: UKIRT K-band imaging
  98. GRB 050215b: Swift XRT Observations
  99. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  100. GRB050215a: No Swift UVOT Detection of Afterglow Emission

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