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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 070311: Swift-XRT refined analysis
  2. GRB 070311: PAIRITEL confirmation of variability of REM candidate
  3. GRB 070311: REM candidate afterglow
  4. GRB 070311: a long GRB detected by INTEGRAL
  5. GRB060901: Candidate optical afterglow
  6. GRB070309: Swift/XRT possible afterglow detection
  7. GRB 070125: Chandra X-ray Confirmation of Jet Break
  8. GRB 070309: Swift/UVOT Upper Limits
  9. GRB 070306, optical observation
  10. Swift UVOT Finding Charts for GRB 070309
  11. GRB 070309: A long GRB detected by INTEGRAL
  12. GRB 070125: X-ray light curve analysis
  13. VLA observation of GRB 070306
  14. IBAS Alert 4162: Not a GRB
  15. GRB 070306: NOT observations
  16. GRB 070306 Swift/UVOT refined analysis
  17. GRB070306: confirmation of near infrared afterglow
  18. GRB 070306: ART-3 early optical and near infrared constraints
  19. GRB 070306: IR observations and candidate afterglow
  20. GRB 070306, Swift-BAT refined analysis
  21. GRB 070306: XRT Team Refined Analysis
  22. GRB 070306: Optical and IR observations with KANATA
  23. GRB070306 - SDSS Pre-burst Observations
  24. GRB 070306: Swift detection of a burst
  25. GRB 070223: NIR observations at WHT
  26. GRB070227: Swift-XRT refined analysis
  27. GRB 060605 new redshift
  28. GRB 070125, deep late-time optical observation
  29. VLA observation of GRB 070224
  30. GRB 070227: optical observations
  31. GRB 070223: Optical Observations
  32. GRB 070227: optical observations
  33. GRB 070227: Swift/UVOT Upper Limits
  34. GRB 070227: TAROT La Silla observatory optical observations
  35. GRB 070227, Swift-BAT refined analysis
  36. GRB070227: possible X-ray afterglow detection
  37. GRB 070227: Swift detection of a burst in ground analysis
  38. GRB 920925C: optical afterglow candidate
  39. GRB 070224: Optical afterglow confirmation
  40. IBAS Alert n. 4144: not a GRB
  41. GRB 070224: Swift/UVOT Upper Limits
  42. GRB070224: Swift-XRT Astrometrically Corrected Position
  43. VLA observation of GRB 070223
  44. VLA observation of GRB 070220
  45. GRB070224: Magellan Imaging Observations
  46. GRB 070224: WHT K-band imaging
  47. GRB 070224: MDM Observations
  48. GRB070224: Gemini Imaging Observations
  49. GRB 070224: SARA upper limit
  50. GRB070224: Swift-XRT Refined Analysis
  51. GRB 070224: optical afterglow candidate
  52. GRB 070224, Swift-BAT refined analysis
  53. GRB 070224: MASTER-Net refind analysis
  54. GRB 070224: MASTER-VWF-Kislovodsk observations
  55. GRB 070224: MASTER observations
  56. GRB 070224: Swift detection of a burst
  57. GRB 070223: Optical observations
  58. RHESSI Spectrum of GRB070220
  59. GRB070223: Swift/UVOT refined analysis
  60. GRB 070223: Optical-IR observation with KANATA
  61. GRB 070223, Swift-BAT refined analysis
  62. GRB070223: MASTER-VWF-Kislovodsk observations
  63. GRB 070223: Swift-XRT Refined Analysis
  64. GRB 070220: pseudo-z~2.15 from spectral parameters of the prompt
  65. GRB070223 - SDSS Pre-Burst Observations
  66. GRB 070223: Liverpool Telescope Possible Afterglow Candidate
  67. GRB 070223: MDM Observations
  68. GRB070223: Swift burst
  69. Konus-Wind and Konus-A observations of GRB 070220
  70. GRB 070220: MITSuME Okayama Optical Observation
  71. GRB 070220: ART-3 Optical and NIR limits
  72. GRB 070220 Swift-BAT Refined Analysis
  73. Swift/UVOT refined analysis of GRB070220
  74. GRB 070209: Swift XRT refined analysis
  75. GRB 070220: Swift-XRT Refined Analysis
  76. GRB 070220: Observation with the KANATA 1.5m telescope
  77. GRB 070219: Gemini Observations
  78. GRB 070220 : Faulkes Telescope North optical limit
  79. GRB 070220: Swift detection of a burst
  80. GRB070219: MASTER-VWF-Kislovodsk observations
  81. GRB 070219: XRT Refined Analysis
  82. GRB 070219: Swift/UVOT Upper limits
  83. GRB 070219: I-band observations
  84. GRB 070219, Swift-BAT refined analysis
  85. GRB 070219: optical TNG observations
  86. GRB 070219: Liverpool Telescope Observations
  87. GRB 070219: ROTSE-III Optical Limits
  88. GRB070219 - SDSS Pre-Burst Observations
  89. GRB 070219: Swift detection of a burst
  90. IPN triangulation of GRB070201 (refined error box using MESSENGER data)
  91. GRB 070125 observations with the GMRT
  92. GRB 070209: Redshift of a galaxy in the error circle of XRT source
  93. Swift-BAT trigger 260304 is NOT a burst or transient
  94. GRB 060927: PROMPT Observations
  95. GRB 070201: Correction to GCN 6094
  96. GRB 070129: MDM I-band Detection
  97. GRB 070125: Break in Optical Decay
  98. GRB 070209: Swift XRT analysis
  99. GRB 070201: clarification on localization and Konus-Wind spectra
  100. GRB070208: optical observations

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