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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"

5812 results found.

  1. GRB 050807: ROTSE-III Optical Limits
  2. GRB 050730 XMM-Newton observation
  3. GRB 050724: Chandra Observations of the X-ray Afterglow
  4. GRB050724: a short-burst detected by Swift
  5. GRB050712: optical limits
  6. GRB 050713B
  7. GRB 050713 : Planned XMM-Newton observation
  8. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  9. GRB 050701: Swift XRT afterglow position
  10. GRB050607: refined analysis of prompt REM observations
  11. GRB 050607: RAPTOR-S Early Optical Limits
  12. GRB050607: KAIT optical limits
  13. GRB 050607: Optical decay and spectral slope
  14. GRB050607,optical observation
  15. GRB 050607 - XRT refined data analysis
  16. Optical Afterglow of GRB 050607
  17. GRB050607: Swift Detection of a long GRB
  18. GRB050607: P60 Observations
  19. GRB050525: Optical observations
  20. GRB 050520: Swift XRT refined analysis
  21. XRF050509C: Chandra Afterglow Detection
  22. Swift-BAT trigger 122203 is not a real GRB
  23. GRB050502b: Early Observation
  24. GRB 050509b: Swift/UVOT follow-up measurements
  25. GRB050509c (=H3751): An X-Ray Flash Localized By HETE
  26. Swift UVOT Follow-up Observations of GRB 050509B
  27. GRB050509a: Swift UVOT observations
  28. GRB 050509b: Optical observations
  29. GRB 050505: Keck I-band Magnitude
  30. GRB 050505: early time observations
  31. GRB 050505 UVOT
  32. GRB050505: Optical Afterglow Candidate
  33. GRB 050505: Swift XRT Position
  34. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  35. GRB050502b: Afterglow Confirmation
  36. GRB 050502b, V band Observations
  37. GRB 050502a: RBO Observations
  38. GRB050502B Swift-BAT refined analysis
  39. GRB050502B: I band source in XRT error circle
  40. GRB 050502b: Swift XRT Position
  41. Swift Detection of the Bright Burst GRB050502b
  42. GRB050326: analysis of the XMM-Newton observation
  43. GRB 050416,optical observation
  44. GRB 050416: KAIT observations
  45. GRB050408: optical observation
  46. GRB 050408: Subaru Observations
  47. GRB 050408: Mercator Optical Observations
  48. GRB 050408, SMARTS optical/IR afterglow observations
  49. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  50. GRB 050402A: IR Observations
  51. GRB050331: No Afterglow Detected
  52. GRB 050331: Swift UVOT Source
  53. GRB 050331: Swift XRT Position
  54. Konus-Wind observation of GRB 050326
  55. GRB 050326 BAT refined analysis
  56. GRB050326: delayed XRT observation
  57. Swift-BAT detection of a bright GRB 050326
  58. GRB 050319: ROTSE-III Refined Analysis
  59. GRB 050319 R band observations
  60. GRB 050319: Swift-UVOT detection of the afterglow
  61. GRB050319,optical observation
  62. Swift Detection of GRB 050319
  63. GRB050223: analysis of the XMM-Newton observation
  64. GRB 050315, SMARTS optical/IR afterglow observations
  65. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  66. GRB050309: CONCAM pre-trigger and trigger coincident optical
  67. GRB 050306: optical afterglow
  68. GRB 050306: Confirmation of X-ray afterglow
  69. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  70. GRB 050306: Possible X-ray Afterglow Position from the Swift
  71. PROMPT VRcIc Observations of GRB 050223
  72. GRB 050223 Swift/BAT detection of a burst
  73. GRB 050223: Swift XRT Position
  74. GRB 050215b: XRT confirmation of IR afterglow candidate
  75. GRB 050215b: Swift XRT Source Variability
  76. GRB 050209 Optical observations
  77. GRB041219: P60 Optical Observations
  78. GRB 041218: Optical observations
  79. GRB 041016: Optical limits
  80. SGR 1806-20 still active
  81. GRB040924: Optical afterglow properties
  82. GRB040916 optical limits 17 min after GRB
  83. GRB040916: Optical observations
  84. GRB/XRF040912,optical observations
  85. An intense burst from SGR1806-20
  86. IBAS GRB Alerts 1978-1980
  87. GRB040903 - A XRF?
  88. MASTER: GRB040827 possible OT
  89. GRB 040827 : Planned XMM-Newton observation
  90. GRB 040827 - A long GRB detected by INTEGRAL
  91. XRF040701: VLA Observations
  92. GRB040709 J,H-band observations
  93. IPN Summary of SGR1806-20 Activity in 2004
  94. GRB 040423 (=H3175): A Long GRB Localized by HETE
  95. GRB 040319 (=H3128): An X-Ray-Rich GRB Localized by the HETE-2 WXM and SXC
  96. GRB031220: Palomar Observations
  97. GRB 031220 : Kyoto Optical Observation
  98. GRB 031220: Optical observation at Tokyo Tech
  99. GRB 031203: Discovery of a dust echo
  100. GRB031203: K' Photometry of the likely GRB host

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