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

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