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

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