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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. GRB060801: optical upper limit in R
  2. GRB 060801: Swift XRT refined analysis
  3. GRB 060801: Refined analysis of the Swift-BAT short hard burst
  4. GRB 060801, optical observation
  5. GRB 060801: Kanazawa Optical Observation
  6. GRB 060801: Swift detection of a short burst
  7. GRB060729: ROTSE-III Observations of the Slow Optical Decay
  8. GRB 060218 / SN 2006aj Nebular Spectrum
  9. IBAS Alert n. 3415: not a GRB
  10. Swift-BAT trigger 221873 is not a GRB or a Transient
  11. GRB 060729 redshift
  12. GRB 060719: TORTOREM optical upper limits
  13. GRB 060729: Swift/UVOT Detections
  14. GRB 060729: Refined analysis of the Swift-BAT burst
  15. GRB 060729: Swift-XRT refined analysis
  16. GRB 060729 : Planned XMM-Newton observation
  17. GRB 060729: Swift/UVOT Observations
  18. GRB 060729: ROTSE-III Detection of Optical Counterpart
  19. GRB 060729: Swift detection of a burst with an UVOT optical counterpart
  20. GRB 060728: Swift/UVOT Upper Limits
  21. GRB 060728: Refined analysis of the Swift-BAT burst
  22. GRB 060728, SMARTS optical/IR observations
  23. Swift/XRT preliminary analysis
  24. GRB 060728: Swift detection of a burst
  25. GRB060614 ATCA Radio Limits
  26. GRB 060218 (SN 2006aj): IR afterglow detection six months after the
  27. GRB 060714: Swift/UVOT Observations
  28. GRB060719: prompt NIR observations with REM
  29. GRB 060714: NOT observations
  30. GRB 060719: near-infrared afterglow
  31. GRB 060719: correction to the coordinates reported in GCN 5347
  32. GRB 060522: VLA observation
  33. GRB 060719: Swift/UVOT Upper Limits
  34. GRB 060719: VLT/ISAAC observations
  35. GRB 060719: Refined analysis of the Swift-BAT burst
  36. GRB 060719: XRT refined analysis
  37. GRB 060719: further analysis of VLT observations
  38. GRB 060719: optical limit by Pi-of-the-Sky
  39. GRB060719: FRAM early follow-up limit
  40. GRB 060719: prompt PROMPT observations
  41. GRB060719: REM NIR Observations
  42. GRB 060719: Continued LCO optical observations
  43. GRB 060719: VLT observations
  44. GRB 060719: LCO optical observations
  45. GRB 060719: Swift detection of a burst
  46. GRB 060717: Swift XRT refined analysis
  47. GRB 060714: OA fading and a possible host detection
  48. GRB060714: optical observations
  49. GRB 060717: NOT observations
  50. GRB 060714: Refined analysis of the Swift-BAT burst
  51. GRB 060717 optical upper limit
  52. GRB060717: Swift/UVOT upper limits
  53. GRB 060717: Swift XRT refined position
  54. GRB 060717: Swift-BAT refined analysis
  55. GRB060717 - SDSS Pre-burst Observations
  56. GRB 060714: REM infrared observations
  57. GRB 060717, optical observation
  58. GRB 060717: Swift detection of a burst
  59. GRB060714: correction to GCN 5324
  60. GRB060714: optical observations
  61. GRB 060714, SMARTS optical/IR afterglow observation
  62. GRB 060714 : Liverpool Telescope Observations
  63. GRB 060714: Swift XRT refined analysis
  64. GRB 060714: OA redshift
  65. GRB 060708: VLT spectroscopy
  66. GRB060708: MARGE low resolution spectrum observations
  67. GRB060714: optical observations
  68. Swift-BAT trigger 219136 is not a GRB
  69. Correction to Circular 5314: Circular refers to GRB 060714
  70. GRB060707 possible optical confirmation
  71. Swift trigger 219136 is probably not a GRB
  72. GRB 060714, optical observation
  73. GRB 060714: Swift detection of a burst with an UVOT optical afterglow
  74. GRB 060605: SkyNet Optical Limits
  75. GRB060712: P60 Observations
  76. GRB 060712: XRT refined analysis
  77. GRB 060712: Swift/UVOT Upper Limits
  78. GRB060526: optical observations
  79. GRB 060712: XRT refined position
  80. GRB 060712: Refined analysis of the Swift-BAT burst
  81. GRB060712: MASTER optical observation
  82. GRB120706: MASTER optical observation
  83. GRB 060712: Swift detection of a burst
  84. Host galaxy of GRB050904: 250 GHz upper limit with MAMBO at the IRAM 30m
  85. GRB 060708: PROMPT Optical Limits
  86. GRB 060707: OA fading and redshift
  87. GRB 060708: Swift-XRT refined analysis
  88. GCN 060708: Swift-UVOT Observations
  89. GRB 060708: Refined analysis of the Swift-BAT burst
  90. GCN 060707: Swift-UVOT observations
  91. GRB 060707: Swift-XRT refined analysis
  92. GRB 060708: Swift detection of a burst with an UVOT countpart
  93. GRB060707 possible optical confirmation
  94. GRB 060707: BOOTES-IR optical afterglow candidate
  95. GRB 060707: Refined analysis of the Swift-BAT burst
  96. GRB 060707: BOOTES-IR optical observation
  97. GRB060614: Possible SN Bump in UVOT U Band Light Curve
  98. GRB 060707: Swift detection of a burst
  99. GRB 060515: Upper Limit on Host Galaxy
  100. GRB 050223: Magellan redshift

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