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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: SARA upper limit
  2. GRB 070309: variability of the XRT afterglow candidate
  3. GRB 070311: MDM Optical Follow-up
  4. GRB 070311: RAPTOR Detection of Optical Emission
  5. GRB070311: FRAM early follow-up limit
  6. GRB 070311: P60 Observations
  7. GRB 070311: MDM Optical Detection
  8. GRB 070311: Swift/UVOT Upper Limits
  9. GRB 070311: MITSuME Okayama Optical Observation
  10. GRB 070311: Swift-XRT refined analysis
  11. GRB 070311: PAIRITEL confirmation of variability of REM candidate
  12. GRB 070311: REM candidate afterglow
  13. GRB 070311: a long GRB detected by INTEGRAL
  14. GRB060901: Candidate optical afterglow
  15. GRB070309: Swift/XRT possible afterglow detection
  16. GRB 070125: Chandra X-ray Confirmation of Jet Break
  17. GRB 070309: Swift/UVOT Upper Limits
  18. GRB 070306, optical observation
  19. Swift UVOT Finding Charts for GRB 070309
  20. GRB 070309: A long GRB detected by INTEGRAL
  21. GRB 070125: X-ray light curve analysis
  22. VLA observation of GRB 070306
  23. IBAS Alert 4162: Not a GRB
  24. GRB 070306: NOT observations
  25. GRB 070306 Swift/UVOT refined analysis
  26. GRB070306: confirmation of near infrared afterglow
  27. GRB 070306: ART-3 early optical and near infrared constraints
  28. GRB 070306: IR observations and candidate afterglow
  29. GRB 070306, Swift-BAT refined analysis
  30. GRB 070306: XRT Team Refined Analysis
  31. GRB 070306: Optical and IR observations with KANATA
  32. GRB070306 - SDSS Pre-burst Observations
  33. GRB 070306: Swift detection of a burst
  34. GRB 070223: NIR observations at WHT
  35. GRB070227: Swift-XRT refined analysis
  36. GRB 060605 new redshift
  37. GRB 070125, deep late-time optical observation
  38. VLA observation of GRB 070224
  39. GRB 070227: optical observations
  40. GRB 070223: Optical Observations
  41. GRB 070227: optical observations
  42. GRB 070227: Swift/UVOT Upper Limits
  43. GRB 070227: TAROT La Silla observatory optical observations
  44. GRB 070227, Swift-BAT refined analysis
  45. GRB070227: possible X-ray afterglow detection
  46. GRB 070227: Swift detection of a burst in ground analysis
  47. GRB 920925C: optical afterglow candidate
  48. GRB 070224: Optical afterglow confirmation
  49. IBAS Alert n. 4144: not a GRB
  50. GRB 070224: Swift/UVOT Upper Limits
  51. GRB070224: Swift-XRT Astrometrically Corrected Position
  52. VLA observation of GRB 070223
  53. VLA observation of GRB 070220
  54. GRB070224: Magellan Imaging Observations
  55. GRB 070224: WHT K-band imaging
  56. GRB 070224: MDM Observations
  57. GRB070224: Gemini Imaging Observations
  58. GRB 070224: SARA upper limit
  59. GRB070224: Swift-XRT Refined Analysis
  60. GRB 070224: optical afterglow candidate
  61. GRB 070224, Swift-BAT refined analysis
  62. GRB 070224: MASTER-Net refind analysis
  63. GRB 070224: MASTER-VWF-Kislovodsk observations
  64. GRB 070224: MASTER observations
  65. GRB 070224: Swift detection of a burst
  66. GRB 070223: Optical observations
  67. RHESSI Spectrum of GRB070220
  68. GRB070223: Swift/UVOT refined analysis
  69. GRB 070223: Optical-IR observation with KANATA
  70. GRB 070223, Swift-BAT refined analysis
  71. GRB070223: MASTER-VWF-Kislovodsk observations
  72. GRB 070223: Swift-XRT Refined Analysis
  73. GRB 070220: pseudo-z~2.15 from spectral parameters of the prompt
  74. GRB070223 - SDSS Pre-Burst Observations
  75. GRB 070223: Liverpool Telescope Possible Afterglow Candidate
  76. GRB 070223: MDM Observations
  77. GRB070223: Swift burst
  78. Konus-Wind and Konus-A observations of GRB 070220
  79. GRB 070220: MITSuME Okayama Optical Observation
  80. GRB 070220: ART-3 Optical and NIR limits
  81. GRB 070220 Swift-BAT Refined Analysis
  82. Swift/UVOT refined analysis of GRB070220
  83. GRB 070209: Swift XRT refined analysis
  84. GRB 070220: Swift-XRT Refined Analysis
  85. GRB 070220: Observation with the KANATA 1.5m telescope
  86. GRB 070219: Gemini Observations
  87. GRB 070220 : Faulkes Telescope North optical limit
  88. GRB 070220: Swift detection of a burst
  89. GRB070219: MASTER-VWF-Kislovodsk observations
  90. GRB 070219: XRT Refined Analysis
  91. GRB 070219: Swift/UVOT Upper limits
  92. GRB 070219: I-band observations
  93. GRB 070219, Swift-BAT refined analysis
  94. GRB 070219: optical TNG observations
  95. GRB 070219: Liverpool Telescope Observations
  96. GRB 070219: ROTSE-III Optical Limits
  97. GRB070219 - SDSS Pre-Burst Observations
  98. GRB 070219: Swift detection of a burst
  99. IPN triangulation of GRB070201 (refined error box using MESSENGER data)
  100. GRB 070125 observations with the GMRT

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