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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 060805: Swift detection of a burst
  2. GRB 060804: Swift UVOT observations
  3. GRB 060804: Swift-XRT Team Refined Analysis
  4. GRB 060804: Refined analysis of the Swift-BAT burst
  5. GRB 060804: Swift detection of a burst with a possible UVOT counterpart
  6. GRB 060728: Upper limits of the X-ray emission
  7. GRB 060801: no variability of optical sources
  8. IBAS Alert 3418: not a GRB
  9. GRB 060801: WSRT Radio Observations
  10. GRB 060801: XRT/SDSS Frame Offset and Refined XRT Position
  11. GRB060801: Radio Observations
  12. GRB 051109B: Bright spiral host galaxy at low redshift
  13. GRB 060801: optical observations at FORS2/VLT
  14. GRB060801: Swift/UVOT Upper Limits
  15. GRB 060801: optical observations at Hanle and Calar Alto
  16. GRB060801: optical upper limit in R
  17. GRB 060801: Swift XRT refined analysis
  18. GRB 060801: Refined analysis of the Swift-BAT short hard burst
  19. GRB 060801, optical observation
  20. GRB 060801: Kanazawa Optical Observation
  21. GRB 060801: Swift detection of a short burst
  22. GRB060729: ROTSE-III Observations of the Slow Optical Decay
  23. GRB 060218 / SN 2006aj Nebular Spectrum
  24. IBAS Alert n. 3415: not a GRB
  25. Swift-BAT trigger 221873 is not a GRB or a Transient
  26. GRB 060729 redshift
  27. GRB 060719: TORTOREM optical upper limits
  28. GRB 060729: Swift/UVOT Detections
  29. GRB 060729: Refined analysis of the Swift-BAT burst
  30. GRB 060729: Swift-XRT refined analysis
  31. GRB 060729 : Planned XMM-Newton observation
  32. GRB 060729: Swift/UVOT Observations
  33. GRB 060729: ROTSE-III Detection of Optical Counterpart
  34. GRB 060729: Swift detection of a burst with an UVOT optical counterpart
  35. GRB 060728: Swift/UVOT Upper Limits
  36. GRB 060728: Refined analysis of the Swift-BAT burst
  37. GRB 060728, SMARTS optical/IR observations
  38. Swift/XRT preliminary analysis
  39. GRB 060728: Swift detection of a burst
  40. GRB060614 ATCA Radio Limits
  41. GRB 060218 (SN 2006aj): IR afterglow detection six months after the
  42. GRB 060714: Swift/UVOT Observations
  43. GRB060719: prompt NIR observations with REM
  44. GRB 060714: NOT observations
  45. GRB 060719: near-infrared afterglow
  46. GRB 060719: correction to the coordinates reported in GCN 5347
  47. GRB 060522: VLA observation
  48. GRB 060719: Swift/UVOT Upper Limits
  49. GRB 060719: VLT/ISAAC observations
  50. GRB 060719: Refined analysis of the Swift-BAT burst
  51. GRB 060719: XRT refined analysis
  52. GRB 060719: further analysis of VLT observations
  53. GRB 060719: optical limit by Pi-of-the-Sky
  54. GRB060719: FRAM early follow-up limit
  55. GRB 060719: prompt PROMPT observations
  56. GRB060719: REM NIR Observations
  57. GRB 060719: Continued LCO optical observations
  58. GRB 060719: VLT observations
  59. GRB 060719: LCO optical observations
  60. GRB 060719: Swift detection of a burst
  61. GRB 060717: Swift XRT refined analysis
  62. GRB 060714: OA fading and a possible host detection
  63. GRB060714: optical observations
  64. GRB 060717: NOT observations
  65. GRB 060714: Refined analysis of the Swift-BAT burst
  66. GRB 060717 optical upper limit
  67. GRB060717: Swift/UVOT upper limits
  68. GRB 060717: Swift XRT refined position
  69. GRB 060717: Swift-BAT refined analysis
  70. GRB060717 - SDSS Pre-burst Observations
  71. GRB 060714: REM infrared observations
  72. GRB 060717, optical observation
  73. GRB 060717: Swift detection of a burst
  74. GRB060714: correction to GCN 5324
  75. GRB060714: optical observations
  76. GRB 060714, SMARTS optical/IR afterglow observation
  77. GRB 060714 : Liverpool Telescope Observations
  78. GRB 060714: Swift XRT refined analysis
  79. GRB 060714: OA redshift
  80. GRB 060708: VLT spectroscopy
  81. GRB060708: MARGE low resolution spectrum observations
  82. GRB060714: optical observations
  83. Swift-BAT trigger 219136 is not a GRB
  84. Correction to Circular 5314: Circular refers to GRB 060714
  85. GRB060707 possible optical confirmation
  86. Swift trigger 219136 is probably not a GRB
  87. GRB 060714, optical observation
  88. GRB 060714: Swift detection of a burst with an UVOT optical afterglow
  89. GRB 060605: SkyNet Optical Limits
  90. GRB060712: P60 Observations
  91. GRB 060712: XRT refined analysis
  92. GRB 060712: Swift/UVOT Upper Limits
  93. GRB060526: optical observations
  94. GRB 060712: XRT refined position
  95. GRB 060712: Refined analysis of the Swift-BAT burst
  96. GRB060712: MASTER optical observation
  97. GRB120706: MASTER optical observation
  98. GRB 060712: Swift detection of a burst
  99. Host galaxy of GRB050904: 250 GHz upper limit with MAMBO at the IRAM 30m
  100. GRB 060708: PROMPT Optical Limits

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