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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"

16156 results found.

  1. Correction to GCN 4816 on GRB060218
  2. GRB 060218/SN 2006aj: optical observations
  3. GRB060218: Optical brightening in V and R
  4. GRB 060223: Keck redshift
  5. GRB 060223: Swift/UVOT Confirmation of Optical Afterglow
  6. Spectral properties of GRB060218/SN2006aj
  7. GRB 060218: rebrightening
  8. GRB 060218: emergence of the underlying SN spectrum
  9. GRB 060218: Decline in r-band flux
  10. GRB 060218: spectroscopic observations
  11. GRB060218: Optical Spectroscopy of GRB-SN
  12. GRB060218: VLT spectroscopy
  13. GRB 060218: Optical Observations at Xinglong Obs.
  14. GRB060218: UV Detection and Light Curves
  15. GRB060218: Radio Afterglow Discovery
  16. GRB 060218: MDM Redshift
  17. GRB 060218: optical/nIR observations at La Palma
  18. Oddball GRB 060218, transient or GRB?
  19. Brightening of the Optical Counterpart of the Possible GRB 060218
  20. GRB 060218: MDM Observations
  21. GRB 060218A: ROTSE-III Possible Optical Flare
  22. Further UVOT Observations of the Candidate Optical Afterglow for GRB 060218
  23. GRB 060213: optical afterglow not confirmed
  24. Swift UVOT observations of GRB060213
  25. GRB 060213: optical afterglow candidate
  26. GRB 060206: Confirmation of Rapid Fading at Optical Wavelengths
  27. GRB 060211b: WIRO NIR Observations
  28. GRB060213:_MASTER_optical_observation
  29. GRB060206: Swift XRT observations of an unbroken powerlaw decay
  30. GRB 060210: Radio Observations
  31. GRB 060211a: WIRO NIR Observations
  32. GRB060211B: REM optical and NIR observations
  33. GRB060121: optical observations
  34. GRB060110: optical observations
  35. GRB060105: optical observations
  36. GRB 060210: ARC NIR Detection of Afterglow and Possible Host Galaxy
  37. GRB 060206: SOAR Detections
  38. GRB 050826: Optical Afterglow and Host Galaxy
  39. GRB060211b: optical observation
  40. GRB 060210: Optical Observations
  41. GRB060211: Faulkes North observation
  42. GRB 060211: ROTSE-III Optical Limits
  43. GRB060210: Swift XRT Refined Analysis
  44. GRB060206, optical observations
  45. GRB 060210 : Xinglong and Lulin optical limit
  46. GRB060210: Optical Observations
  47. GRB060210: Gemini absorption spectroscopy
  48. GRB060210: Early Optical Observations
  49. GRB 060210: optical evolution
  50. GRB060210: Optical afterglow
  51. GRB060209: RTT150 optical observations
  52. GRB 060209 : TAROT optical observation
  53. GRB060209A: MASTER optical observation
  54. GRB 060206: WSRT Radio Observations
  55. GRB 060206: More PROMPT Detections
  56. GRB 060121 : WIDGET Pre-trigger limit
  57. GRB 060206: optical observations at Asiago
  58. Orphan GRB Afterglow candidate
  59. GRB 060206: Subaru/FOCAS optical spectroscopy
  60. GRB 060206: Super-LOTIS observations
  61. GRB060204A: Swift/UVOT observations
  62. GRB 060206 : Lulin optical observations
  63. GRB060206: Swift XRT Refined Analysis
  64. GRB060206: Liverpool Telescope observation
  65. GRB060206: P60 Optical Observations
  66. GRB060206: Swift XRT Position
  67. GRB 060206: RAPTOR observations of afterglow candidate variability.
  68. GRB 060206: High redshift burst
  69. GRB060206 - Swift UVOT Confirmation of Optical Afterglow
  70. GRB060206: Optical afterglow
  71. GRB 060204C: XRT analysis of Swift J061223.0+701243.9
  72. GRB060203: WHT Z-band observations
  73. GRB060204C: optical observation
  74. GRB 060204B: BVRi-band detections of optical afterglow
  75. GRB 060204A: FRAM optical observations
  76. GRB 060204C: optical observations
  77. GRB 060204B: ART early limit
  78. GRB060204B: Swift XRT Team Refined Analysis
  79. GRB 060204C: BOOTES-IR optical limits
  80. GRB 060204C: Liverpool Telescopes optical limit
  81. GRB 060204C: ROTSE-III Optical Limits
  82. GRB 060124: Radio Observations
  83. GRB 060204B: ART optical limit
  84. GRB060204B, optical observation
  85. GRB 060203: RTT150 optical observations
  86. GRB060203: Swift XRT Team Refined Analysis
  87. GRB060203 - Swift UVOT observation
  88. GRB 060203: P60 Confirmation of Optical Afterglow
  89. Possible GRB 060203: candidate optical counterpart
  90. Possible GRB 060203: optical observations at Asiago
  91. GRB 060202: Optical Afterglow Candidate from Keck/LRIS
  92. GRB060202, optical observation
  93. GRB060202: Faulkes North observation
  94. GRB 051211A: MDM Observations
  95. GRB060130: Optical imaging
  96. GRB 060130, SMARTS optical observations
  97. GRB 060130: FRAM optical observations
  98. Possible GRB 051221B: MDM Correction
  99. GRB050121: optical observation
  100. GRB050121b: optical observation

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