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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 060729: ROTSE-III Detection of Optical Counterpart
  2. GRB 060729: Swift detection of a burst with an UVOT optical counterpart
  3. GRB 060728: Swift/UVOT Upper Limits
  4. GRB 060728: Refined analysis of the Swift-BAT burst
  5. GRB 060728, SMARTS optical/IR observations
  6. Swift/XRT preliminary analysis
  7. GRB 060728: Swift detection of a burst
  8. GRB060614 ATCA Radio Limits
  9. GRB 060218 (SN 2006aj): IR afterglow detection six months after the
  10. GRB 060714: Swift/UVOT Observations
  11. GRB060719: prompt NIR observations with REM
  12. GRB 060714: NOT observations
  13. GRB 060719: near-infrared afterglow
  14. GRB 060719: correction to the coordinates reported in GCN 5347
  15. GRB 060522: VLA observation
  16. GRB 060719: Swift/UVOT Upper Limits
  17. GRB 060719: VLT/ISAAC observations
  18. GRB 060719: Refined analysis of the Swift-BAT burst
  19. GRB 060719: XRT refined analysis
  20. GRB 060719: further analysis of VLT observations
  21. GRB 060719: optical limit by Pi-of-the-Sky
  22. GRB060719: FRAM early follow-up limit
  23. GRB 060719: prompt PROMPT observations
  24. GRB060719: REM NIR Observations
  25. GRB 060719: Continued LCO optical observations
  26. GRB 060719: VLT observations
  27. GRB 060719: LCO optical observations
  28. GRB 060719: Swift detection of a burst
  29. GRB 060717: Swift XRT refined analysis
  30. GRB 060714: OA fading and a possible host detection
  31. GRB060714: optical observations
  32. GRB 060717: NOT observations
  33. GRB 060714: Refined analysis of the Swift-BAT burst
  34. GRB 060717 optical upper limit
  35. GRB060717: Swift/UVOT upper limits
  36. GRB 060717: Swift XRT refined position
  37. GRB 060717: Swift-BAT refined analysis
  38. GRB060717 - SDSS Pre-burst Observations
  39. GRB 060714: REM infrared observations
  40. GRB 060717, optical observation
  41. GRB 060717: Swift detection of a burst
  42. GRB060714: correction to GCN 5324
  43. GRB060714: optical observations
  44. GRB 060714, SMARTS optical/IR afterglow observation
  45. GRB 060714 : Liverpool Telescope Observations
  46. GRB 060714: Swift XRT refined analysis
  47. GRB 060714: OA redshift
  48. GRB 060708: VLT spectroscopy
  49. GRB060708: MARGE low resolution spectrum observations
  50. GRB060714: optical observations
  51. Swift-BAT trigger 219136 is not a GRB
  52. Correction to Circular 5314: Circular refers to GRB 060714
  53. GRB060707 possible optical confirmation
  54. Swift trigger 219136 is probably not a GRB
  55. GRB 060714, optical observation
  56. GRB 060714: Swift detection of a burst with an UVOT optical afterglow
  57. GRB 060605: SkyNet Optical Limits
  58. GRB060712: P60 Observations
  59. GRB 060712: XRT refined analysis
  60. GRB 060712: Swift/UVOT Upper Limits
  61. GRB060526: optical observations
  62. GRB 060712: XRT refined position
  63. GRB 060712: Refined analysis of the Swift-BAT burst
  64. GRB060712: MASTER optical observation
  65. GRB120706: MASTER optical observation
  66. GRB 060712: Swift detection of a burst
  67. Host galaxy of GRB050904: 250 GHz upper limit with MAMBO at the IRAM 30m
  68. GRB 060708: PROMPT Optical Limits
  69. GRB 060707: OA fading and redshift
  70. GRB 060708: Swift-XRT refined analysis
  71. GCN 060708: Swift-UVOT Observations
  72. GRB 060708: Refined analysis of the Swift-BAT burst
  73. GCN 060707: Swift-UVOT observations
  74. GRB 060707: Swift-XRT refined analysis
  75. GRB 060708: Swift detection of a burst with an UVOT countpart
  76. GRB060707 possible optical confirmation
  77. GRB 060707: BOOTES-IR optical afterglow candidate
  78. GRB 060707: Refined analysis of the Swift-BAT burst
  79. GRB 060707: BOOTES-IR optical observation
  80. GRB060614: Possible SN Bump in UVOT U Band Light Curve
  81. GRB 060707: Swift detection of a burst
  82. GRB 060515: Upper Limit on Host Galaxy
  83. GRB 050223: Magellan redshift
  84. GRB 060614: SMARTS host galaxy observations
  85. GRB 060614: Detection of a Possible, Late-Time Rebrightening
  86. Correction to GCN 5278 & GCN 5279 (GRBs 060105 & 060109)
  87. GRB 060109: Upper Limit on Host Galaxy
  88. GRB 060105: Upper limit on Host Galaxy
  89. GRB060614: Detection of the host galaxy but no supernova emission
  90. GRB 060614: redshift confirmation
  91. GRB 060614: Redshift
  92. Swift-BAT trigger 215279 is not a GRB
  93. Trigger 215279: Swift detection of a possible burst (GRB 060619)
  94. GRB060614: Optical observations
  95. GRB 060614: spectroscopy
  96. GRB050326: Host Galaxy Candidates
  97. GRB050124: Possible Host Galaxy
  98. GRB050223: Host Galaxy
  99. GRB060512: near IR observations
  100. GRB060526: optical observations

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