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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"

23417 results found.

  1. GRB 060814: P200 NIR Observations
  2. GRB060814: Swift/UVOT upper limits
  3. GRB 060814: VLT optical limits
  4. GRB 060814 - SDSS Pre-Burst Observations
  5. GRB 060814: TAROT optical observations
  6. GRB 060814: Swift detection of a bright burst
  7. GRB060813: Swift/UVOT upper limits
  8. GRB 060813: Swift detection of a burst
  9. GRB051109B: Late-time Radio Observations
  10. A dust-scattering halo detected around SGR 1806-20
  11. Swift detection of an outburst from the 4U 1246-58 LMXB burster
  12. GRB060807: Possible Highly Significant X-ray Emission Lines
  13. GRB 060729: An update on the Swift XRT and UVOT observations
  14. GRB060717: optical observations
  15. GRB 060805B: XRT Team Analysis
  16. GRB060806 is similar to previous activity of SGR1806-20
  17. GRB 060807: UVOT Upper limits
  18. GRB060807: optical afterglow candidate
  19. IPN triangulation of GRB060806 (long, exceptionally bright)
  20. GRB060807 - SDSS Pre-burst Observations
  21. GRB 060805B: Swift/UVOT Upper Limits
  22. GRB 060807, optical observation
  23. GRB 060807: Kanazawa R-band observation
  24. GRB 060807: Swift detection of a burst
  25. IPN triangulation of GRB060805B
  26. GRB060805 Liverpool Telescope observations
  27. GRB 060805: XRT Team Refined Analysis
  28. GRB 060805: Swift/UVOT Upper Limits
  29. GRB 060805: P60 Observations
  30. GRB 060805 - SDSS Pre-Burst Observations
  31. GRB 060805: Swift detection of a burst
  32. GRB 060804: Swift UVOT observations
  33. GRB 060804: Swift detection of a burst with a possible UVOT counterpart
  34. GRB 060728: Upper limits of the X-ray emission
  35. GRB 060801: no variability of optical sources
  36. GRB 060801: XRT/SDSS Frame Offset and Refined XRT Position
  37. GRB060801: Radio Observations
  38. GRB 051109B: Bright spiral host galaxy at low redshift
  39. GRB 060801: optical observations at FORS2/VLT
  40. GRB060801: Swift/UVOT Upper Limits
  41. GRB 060801: Refined analysis of the Swift-BAT short hard burst
  42. GRB 060801, optical observation
  43. GRB 060801: Kanazawa Optical Observation
  44. GRB 060801: Swift detection of a short burst
  45. GRB 060719: TORTOREM optical upper limits
  46. GRB 060729: Swift/UVOT Observations
  47. GRB 060729: Swift detection of a burst with an UVOT optical counterpart
  48. GRB 060728: Swift/UVOT Upper Limits
  49. GRB 060728, SMARTS optical/IR observations
  50. Swift/XRT preliminary analysis
  51. GRB 060728: Swift detection of a burst
  52. GRB060614 ATCA Radio Limits
  53. GRB 060714: Swift/UVOT Observations
  54. GRB060719: prompt NIR observations with REM
  55. GRB 060714: NOT observations
  56. GRB 060719: near-infrared afterglow
  57. GRB 060522: VLA observation
  58. GRB 060719: Swift/UVOT Upper Limits
  59. GRB 060719: VLT/ISAAC observations
  60. GRB 060719: further analysis of VLT observations
  61. GRB 060719: prompt PROMPT observations
  62. GRB060719: REM NIR Observations
  63. GRB 060719: VLT observations
  64. GRB 060719: LCO optical observations
  65. GRB 060719: Swift detection of a burst
  66. GRB060717: Swift/UVOT upper limits
  67. GRB 060717: Swift XRT refined position
  68. GRB060717 - SDSS Pre-burst Observations
  69. GRB 060714: REM infrared observations
  70. GRB 060717, optical observation
  71. GRB 060717: Swift detection of a burst
  72. GRB 060714 : Liverpool Telescope Observations
  73. GRB 060714: OA redshift
  74. GRB 060708: VLT spectroscopy
  75. Swift trigger 219136 is probably not a GRB
  76. GRB 060714, optical observation
  77. GRB 060714: Swift detection of a burst with an UVOT optical afterglow
  78. GRB 060605: SkyNet Optical Limits
  79. GRB060712: P60 Observations
  80. GRB 060712: Swift/UVOT Upper Limits
  81. GRB 060712: XRT refined position
  82. GRB 060712: Refined analysis of the Swift-BAT burst
  83. GRB060712: MASTER optical observation
  84. GRB120706: MASTER optical observation
  85. GRB 060712: Swift detection of a burst
  86. Host galaxy of GRB050904: 250 GHz upper limit with MAMBO at the IRAM 30m
  87. GRB 060708: PROMPT Optical Limits
  88. GRB 060707: OA fading and redshift
  89. GCN 060708: Swift-UVOT Observations
  90. GCN 060707: Swift-UVOT observations
  91. GRB 060708: Swift detection of a burst with an UVOT countpart
  92. GRB 060707: BOOTES-IR optical observation
  93. GRB 060707: Swift detection of a burst
  94. GRB 060515: Upper Limit on Host Galaxy
  95. GRB 050223: Magellan redshift
  96. GRB 060614: Detection of a Possible, Late-Time Rebrightening
  97. GRB 060109: Upper Limit on Host Galaxy
  98. GRB 060105: Upper limit on Host Galaxy
  99. Trigger 215279: Swift detection of a possible burst (GRB 060619)
  100. GRB050326: Host Galaxy Candidates

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