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

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