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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"

16173 results found.

  1. GRB 050315: Swift-BAT further refined analysis
  2. GRB 050315, SMARTS optical/IR afterglow observations
  3. GRB 050315 I-band observations
  4. GRB050315: Radio afterglow
  5. GRB 050315: Optical afterglow identification
  6. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  7. GRB 050315: Early Observations with Swift/UVOT
  8. GRB050223: No XMM-Newton OM detection of afterglow emission
  9. GRB 050306: Radio Observations
  10. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  11. GRB050309: CONCAM pre-trigger and trigger coincident optical
  12. GRB 050306: optical afterglow
  13. GRB 050309, Early optical limits from RAPTOR
  14. GRB 050306: further TAROT optical data
  15. GRB050309: Early optical limit from P60
  16. Swift 107873: P60 Optical Observations
  17. GRB 050306: CORRECTION to date of observation
  18. GRB 050306: No Swift UVOT Optical Counterpart Detected
  19. GRB 050306: REM optical-infrared observations
  20. Swift trigger 107518: optical observation
  21. GRB 050306: TAROT optical observations
  22. GRB 050306,optical observation
  23. GRB050215B: Late-Time Swift UVOT Observations
  24. PROMPT VRcIc Observations of GRB 050223
  25. GRB 050219b: candidate NIR afterglow
  26. GRB 050223: optical observations
  27. GRB050223: No Swift UVOT Detection of Afterglow Emission
  28. GRB050223: ROTSE-III Optical Observations
  29. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  30. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  31. GRB 050219a: Optical observations from LCO
  32. GRB 050219b: Optical and near-IR observations from LCO
  33. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  34. GRB 050219a, optical observations
  35. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  36. GRB050215b: Swift UVOT Detection of Afterglow Emission
  37. GRB 050215B: Radio Observations
  38. GRB 050215b: XRT confirmation of IR afterglow candidate
  39. GRB050215b: P60 Optical Observations
  40. GRB 050215b: Swift XRT Source Variability
  41. GRB 050215b, BOOTES-2 simultaneous optical observations
  42. GRB 050215b: Swift XRT Observations
  43. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  44. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  45. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  46. GRB 050215b, BOOTES-1B optical limit
  47. GRB050215B: ROTSE-III optical observations
  48. GRB050215A: ROTSE-III Optical Observations
  49. GRB050209: TAROT optical observations
  50. GRB 050209(=U11568): Duration and spectrum
  51. short/hard GRB 050202, optical observations
  52. GRB050209: REM optical observations
  53. GRB 050209 Optical observations
  54. GRB050209: P60 Optical Observations
  55. GRB050209 (=U11568): A Long GRB Detected by HETE
  56. GRB 050209: Optical observation
  57. Further analysis of the short Swift-BAT GRB 050202
  58. GRB 050129: Optical observations
  59. GRB 050202: Optical observations with LCO40
  60. GRB 050128 Optical observation with REM
  61. GRB 050128: near-infrared observations with REM
  62. GRB050128,optical observations
  63. GRB 050128: Swift XRT prompt afterglow position
  64. GRB050126: MASTER optical limit for KECK OT
  65. GRB050126: MASTER optical observations
  66. GRB050124: No Swift UVOT Detection of Afterglow Emission
  67. GRB 050124, SMARTS optical/IR observations
  68. GRB050124,optical observation
  69. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  70. GRB050123: optical limit 1.8h before GRB
  71. GRB050123,optical observation
  72. GRB 050123(=H3666): A GRB Localized in Real Time by HETE
  73. CFHTLS optical transient unlikely to be a GRB
  74. Unusual optical transient (GRB ???)
  75. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  76. GRB050117: optical observation
  77. GRB 050117: Optical observation
  78. GRB050117: MASTER optical observations
  79. MASTER:GRB050117 SWIFT
  80. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  81. SGR 1806-20 and extragalactic short-duration GRBs
  82. GRB 041217: Optical observations
  83. GRB041219, early time observations
  84. GRB041228: ROTSE-III Optical Observations
  85. GRB041226: ROTSE-III Optical Observations
  86. GRB041223: decay of the afterglow
  87. GRB041224: ROTSE-III Optical Observations
  88. GRB 041224: near-infrared observations with REM
  89. GRB 041223: XRT afterglow spectrum and light curve
  90. GRB041223: optical and NIR observations with REM
  91. Swift-BAT Time History of GRB041219
  92. GRB 041219: TAROT optical observations
  93. GRB 041218: TAROT optical observations
  94. GRB 041223: Detection of Optical Transient with LCO40
  95. GRB041223: ROTSE-III Optical Observations
  96. GRB 041218: optical observations
  97. GRB 041218: Optical observations
  98. GRB 041219 : optical follow-up observations
  99. Deep RAPTOR observations during GRB 041219
  100. GRB 041218 Optical Observations

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