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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"

24850 results found.

  1. SGR 1900+14 : RXTE observations
  2. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  3. SGR 1900+14: Correction to GCN 1049
  4. GRB 010222 /corrections to VBT data
  5. Millimeter observation of SGR 1900+14
  6. SGR 1900+14: Detection of extended X-ray emission
  7. SGR 1900+14, Chandra observations
  8. SGR1900+14, I-band observations
  9. GRB010412, field photometry
  10. Giant flare from SGR1900+14
  11. GRB 010326b Optical Observations
  12. GRB010412: BeppoSAX GRBM and WFC observations
  13. GRB010324, revised field photometry
  14. REVISED LOCATION OF GRB010326A
  15. GRB 980326: Late-time HST/STIS observations
  16. GRB010324, field photometry
  17. GRB010326B, field photometry
  18. GRB010326, field photometry
  19. GRB010220, field photometry
  20. Further Optical Observations of GRB 010324
  21. GRB010222, CXO X-ray observations
  22. GRB010324, optical observations
  23. GRB010326B: Localization by HETE (2nd GRB for this date)
  24. GRB 010326 optical observations
  25. GRB010326: Refined Localization by HETE
  26. GRB010326: Localization by HETE
  27. Optical Observations of GRB 010324
  28. GRB010222, late-time optical observation
  29. Support extension to the BeppoSAX mission
  30. GRB 010222 - HEGRA GeV/TeV Observations
  31. GRB010222: Chandra X-ray Observatory Observation
  32. GRB010222: Sub-millimeter vanishing act
  33. GRB010222 - Optical observation
  34. GRB 010222, Optical Observations
  35. GRB010222 - Optical observation
  36. GRB 010222: High-Resolution Keck Spectroscopy
  37. GRB 010214, I-band data
  38. GRB 010222
  39. GRB010222 further R-band photometry
  40. GRB010222: R-band data
  41. GRB 010222: Keck Spectroscopy
  42. GRB010214, field photometry
  43. GRB010222, field photometry
  44. GRB010222 further R-band photometry
  45. GRB010222, possible increase of optical decay slope
  46. GRB 010222 Kyoto optical observation
  47. GRB010222 R-BAND OBSERVATION
  48. GRB010214 follow-up from Hanle
  49. GRB 010222: Near-IR Observations
  50. GRB 010222: Optical Observations
  51. GRB010222: Optical decay slope
  52. GRB 010214, Optical Observations
  53. GRB010222, radio observations
  54. GRB010222, optical observations
  55. GRB010222: BeppoSAX/NFI Observations
  56. GRB010214B,Gamma Ray Observations
  57. GRB 010220, simultaneous optical observations
  58. GRB010220: BeppoSAX WFC and GRBM preliminary data
  59. GRB010214, candidate optical afterglow
  60. GRB010214, optical observations
  61. GRB010214: BeppoSAX WFC and GRBM preliminary data
  62. GRB 010214: X-Ray afterglow
  63. GRB 010214 optical observation
  64. GRB010213, Radio Observations
  65. J-Band Observation of GRB 010214.
  66. GRB010213, Near-IR observations
  67. Possible InfraRed Transient of GRB 010214.
  68. GRB 010214, optical observations
  69. GRB010213 detected by HETE
  70. IPN Status Report
  71. HETE Status
  72. IPN/RXTE TRIANGULATION OF GRB010126
  73. GRB010126 Optical Observations
  74. IPN TRIANGULATION OF GRB010126
  75. Optical Observations of GRB 001018 at Keck
  76. IPN TRIANGULATION OF GRB010119 (SHORT/HARD)
  77. Optical observations of GRB 001018 with JCAM
  78. IPN TRIANGULATION OF GRB010115
  79. IPN TRIANGULATION OF GRB010109
  80. IPN TRIANGULATION OF GRB010109
  81. IPN triangulation of GRB010104
  82. IPN triangulation of GRB010103
  83. H band observation of GRB 001212
  84. IPN triangulation of GRB001219
  85. GRB 001212 Optical Observation
  86. GRB 001212 Optical Observation
  87. GRB 001212 possible OA in 2MASS
  88. IPN triangulation of GRB001212
  89. Confirmation of IPN position for GRB001204
  90. IPN triangulation of GRB001204 (short/hard)
  91. GRB001120, optical observations
  92. WSRT 4.8 GHz observations of GRB001109
  93. IPN triangulation of GRB001120
  94. GRB 001109: deep JHK upper limits
  95. GRB 001109 X-ray afterglow with BeppoSAX
  96. CORRECTION to XMM-Newton observation of GRB001025
  97. GRB001109, Radio observations
  98. GRB001105 BVRI field photometry correction
  99. GRB001105, BVRI field photometry
  100. IPN TRIANGULATION OF GRB001105

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