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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"

36042 results found.

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

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