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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"

12054 results found.

  1. GRB060108: Swift detection of its 100th GRB
  2. GRB 060105: MDM Observation
  3. GRB 060105: ISAS observations and near IR upper limit
  4. GRB 060105: Swift/UVOT upper limits
  5. GRB 060105: Mitsume optical observations
  6. GRB 060102 - no XRT afterglow
  7. GRB060105: Swift detection of a bright long burst
  8. GRB051211B: optical observations
  9. GRB 051227: optical observation
  10. GRB 051227: Swift/UVOT Upper Limits (Possible U-band
  11. GRB051117B: optical observation
  12. GRB 051221A: MDM Optical Observations
  13. GRB 051221A: Refined spectral and temporal analysis of the Swift-BAT short hard burst
  14. GRB 051221B: TAROT optical limits
  15. GRB 051221A: RAPTOR Fading Counterpart Constraint
  16. GRB 051221B: BOOTES optical observations.
  17. Swift-BAT detection of a possible burst
  18. GRB 051221: Swift/UVOT upper limits
  19. GRB 051221: Swift detection of a bright short burst
  20. GRB051211A: possible optical candidate
  21. GRB 051211A: Swift/UVOT upper limits
  22. GRB 051211B: Swift/UVOT upper limits - correction
  23. GRB 051211B: Swift/UVOT upper limits
  24. GRB 051211A and GRB051211B: BOOTES simultaneous observations
  25. GRB 051210: Swift/UVOT upper limits
  26. GRB 051211: Swift XRT upper limit
  27. GRB051117B: optical observation
  28. GRB051117B: Swift XRT refined analysis
  29. GRB051117b: No Swift/UVOT Detection
  30. GRB 051109B: GAO 150cm telescope Optical limit
  31. GRB 051109B : Nainital upper limits
  32. GRB050925: analysis of the XMM-Newton observation
  33. GRB 051109A Milagro GeV/TeV Observations
  34. GRB/SGR 050925: XMM-Newton ToO observation
  35. GRB051111: Swift/UVOT Observations
  36. GRB 051103 Milagro GeV/TeV Observations
  37. GRB 051105a: GETS optical limit
  38. GRB 051109b: GETS observation
  39. GRB051109B: no UVOT source detected
  40. GRB051105B: REM Optical observation
  41. GRB051105B: Swift/XRT upper limit
  42. GRB051105B: Swift/UVOT upper limit
  43. GRB051103: optical observations
  44. GRB 051103, optical observations
  45. GRB051103: MASTER: OT limit and host galaxy candidates
  46. GRB051105A: Swift/UVOT Observations
  47. GRB051103:_MASTER_optical_observations
  48. GRB 051105b: ART optical limits
  49. GRB 051105B (INTEGRAL 2701): Optical observation
  50. GRB 051105: Optical limit
  51. GRB051028: Swift/UVOT upper limits
  52. GRB051021B: Swift/UVOT Upper limits
  53. GRB051012: Swift-XRT analysis
  54. GRB051021a: optical observations
  55. GRB 051022: Swift/UVOT Upper Limits
  56. GRB 051021: MDM Upper Limit
  57. GRB 051022 (=H3950): SXC Flight Localization is Valid
  58. GRB051021: Swift/UVOT Upper Limits
  59. GRB051021.63
  60. GRB051021.6: MASTER optical observation
  61. GRB 050502b: Optical limit
  62. GRB 051016A: Swift/UVOT upper limits
  63. GRB 051016B: Swift/UVOT detection
  64. GRB 051016: LCO optical and near-IR imaging
  65. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  66. GRB051006: optical observations
  67. GRB 051006: Swift/UVOT Upper Limits
  68. GRB 051008 - a low redshift low-luminosity burst?
  69. GRB051011: MASTER optical observation
  70. GRB051008 - Swift UVOT upper limits
  71. GRB 051008: R-band upper limit
  72. GRB051008: Radio Observation
  73. GRB051001: Swift UVOT Upper Limits
  74. GRB050922B: optical limit
  75. GRB050925: Swift/XRT limits
  76. GRB/SGR 050925: IR Observations
  77. GRB050922C - Swift UVOT preliminary analysis
  78. GRB050925: Swift UVOT upper limits
  79. GRB050922B: Swift UVOT early upper limits.
  80. GRB 050922B: optical limit
  81. HETE Fregate observations of GRB 050922C
  82. GRB 050922A: Analysis of Swift/XRT TOO observation
  83. GRB050916: Swift/UVOT Upper Limits
  84. GRB 050915B: Swift/UVOT Upper Limits
  85. GRB 050915a: IR Transient
  86. GRB050915: Swift/UVOT upper limits
  87. GRB050915: P60 Optical Observations
  88. GRB050911: Upper limit on X-ray afterglow
  89. Swift-BAT trigger 155072 ground analysis
  90. GRB050911: Swift UVOT followup observations
  91. GRB050908: detection of Swift/UVOT optical counterpart
  92. GRB050908: Swift/UVOT Early upper limits
  93. GRB 050906: Swift XRT upper limit
  94. GRB 050904: BOOTES early R-band observation
  95. GRB 050904: Swift/UVOT observations
  96. GRB050827: Swift/UVOT upper limits
  97. Subaru Observations of GRB050724
  98. GRB050826: Swift/UVOT early upper limits
  99. GRB050824: First 2 hours of power low optical decay?
  100. GRB050824: CORRECTION to UVOT observing times

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