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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. GRB060110, optical observation
  2. GRB 060110: Super-LOTIS observations
  3. GRB 060110: Optical observation
  4. GRB 060110: Correction
  5. Correction to GRB 060109 XRT analysis
  6. GRB 050110: IR Observations
  7. GRB 060110: Optical limit
  8. GRB 060110: Swift-BAT detection of a burst
  9. GRB 060109: Refined Swift-XRT analysis
  10. GRB 060109: Swift/UVOT upper limits
  11. GRB060109, optical observation
  12. GRB 060108: ISAS early observations and near IR upper limit
  13. GRB060108: P200 Ks Observations
  14. GRB 060108: early UKIRT K-band observations
  15. Swift UVOT correction to GCN 4455
  16. GRB 060109: Swift Detection of a long burst
  17. GRB 060108: a dark burst?
  18. GRB 060108: Refined XRT analysis
  19. GRB 060108: VLT J-band observations
  20. GRB 060108: Mitsume optical observations
  21. GRB 060108: Swift/UVOT upper limits
  22. GRB 060105: quick look analysis of the Suzaku/XIS afterglow observation
  23. GRB060108: SDSS pre-burst observations
  24. GRB060108: Faulkes Telescope observation
  25. GRB060108, optical observation
  26. GRB 060108: Refined analysis of the Swift-BAT burst
  27. GRB 060108: Swift XRT position
  28. GRB060108: Swift detection of its 100th GRB
  29. GRB 060105: pseudo-z from spectral parameters of the prompt emission
  30. GRB 060105: Radio observations
  31. GRB 060105: MDM Observation
  32. Konus-Wind observation of GRB 060105
  33. GRB 060105: ISAS observations and near IR upper limit
  34. GRB 060105: Swift/UVOT upper limits
  35. GRB 060105: Mitsume optical observations
  36. GRB 060105: BAT refined analysis
  37. GRB 060102 - no XRT afterglow
  38. GRB 060105: XRT refined analysis
  39. GRB060105: Suzaku-XIS and -HXD observation plan
  40. GRB060105, optical observation
  41. GRB060105 : Kiso optical observation
  42. GRB060105: Swift detection of a bright long burst
  43. Swift-BAT trigger 175653 is not an astrophysical source
  44. GRB 060102: MDM Observation
  45. Swift-BAT trigger 175653 is probably not a GRB
  46. GRB 060102: Swift-BAT refined analysis
  47. Time Correction to GRB 060102
  48. GRB 060102: Swift-BAT detection of a burst
  49. GRB051211B: optical observations
  50. GRB051227: SARA Observations
  51. GRB 051221B: Optical Observations with Kuiper 1.54m
  52. GRB 051227: Likely host galaxy underlying afterglow position
  53. GRB 051227: optical observation
  54. GRB051221B: Radio observations
  55. GRB 051221A: VLA Radio Observations
  56. GRB051227: Radio Observations
  57. GRB 051227: Confirmed fading from Gemini observations
  58. GRB051227: further analysis of VLT images
  59. GRB 051227: optical afterglow
  60. GRB 051227: Swift/UVOT Upper Limits (Possible U-band
  61. GRB 051227: Gemini observations
  62. GRB 051227: Keck Spectroscopy
  63. GRB 051227: Magellan r'-band Imaging/Astrometry
  64. GRB 051227: refined analysis of VLT images
  65. GRB 051227: P60 Observations
  66. GRB 051227: MDM Observation
  67. GRB 051227: R-band object in the XRT error circle
  68. GRB 051227: Joint Swift-HETE Spectral Analysis
  69. GRB 051227: XRT refined analysis
  70. GRB 051227: Further analysis of the Swift-BAT burst
  71. GRB 051227: Refined analysis of the Swift-BAT burst
  72. GRB051227: SDSS pre-burst observations
  73. GRB 051227, optical observation
  74. GRB 051227: Swift detection of a burst
  75. GRB051117B: optical observation
  76. IBAS_alert n. 2719 : not a real GRB
  77. Konus-Wind observation of GRB 051221A
  78. GRB051221A: Suzaku WAM observation of the prompt emission
  79. GRB 051221A: MDM Optical Observations
  80. GRB051016: analysis of the XMM-Newton observation
  81. GRB 051221A: Detection at 251nm with Swift UVOT
  82. GRB 051221A: Chandra Afterglow Position
  83. GRB 051221A: Refined spectral and temporal analysis of the Swift-BAT short hard burst
  84. GRB 051221B: ROTSE-III Optical Limits
  85. GRB 051221B: TAROT optical limits
  86. GRB 051221A: WSRT Radio Observations
  87. GRB 051221: Redshift from Gemini
  88. GRB 051221: Continued fading of optical afterglow
  89. GRB 051221B: Refined analysis of the Swift-BAT burst
  90. Possible GRB 051221B: MDM Optical Detection
  91. GRB 051221A: RAPTOR Fading Counterpart Constraint
  92. GRB 051221B: BOOTES optical observations.
  93. Possible GRB 051221B: Swift XRT position
  94. GRB 051211A: Evidence This Is a Short Burst from Analysis of Spectral
  95. Swift-BAT detection of a possible burst
  96. GRB 051221: Discovery of fading optical afterglow
  97. GRB 051221: Swift XRT refined analysis
  98. GRB 051221: Swift/UVOT upper limits
  99. GRB 051221: Possible nearby cluster
  100. GRB 051221: No variability in Gemini data

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