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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"

26422 results found.

  1. Support extension to the BeppoSAX mission
  2. GRB 010222 - HEGRA GeV/TeV Observations
  3. GRB010222: Chandra X-ray Observatory Observation
  4. GRB010222: Sub-millimeter vanishing act
  5. GRB010222 - Optical observation
  6. GRB 010222, Optical Observations
  7. GRB010222 - Optical observation
  8. GRB 010222: High-Resolution Keck Spectroscopy
  9. GRB 010214, I-band data
  10. GRB 010222
  11. GRB010222 further R-band photometry
  12. GRB010222: R-band data
  13. GRB 010222: Keck Spectroscopy
  14. GRB010214, field photometry
  15. GRB010222, field photometry
  16. GRB010222 further R-band photometry
  17. GRB010222, possible increase of optical decay slope
  18. GRB 010222 Kyoto optical observation
  19. GRB010222 R-BAND OBSERVATION
  20. GRB010214 follow-up from Hanle
  21. GRB 010222: Near-IR Observations
  22. GRB 010222: Optical Observations
  23. GRB010222: Optical decay slope
  24. GRB 010214, Optical Observations
  25. GRB010222, radio observations
  26. GRB010222, optical observations
  27. GRB010222: BeppoSAX/NFI Observations
  28. GRB010214B,Gamma Ray Observations
  29. GRB 010220, simultaneous optical observations
  30. GRB010220: BeppoSAX WFC and GRBM preliminary data
  31. GRB010214, candidate optical afterglow
  32. GRB010214, optical observations
  33. GRB010214: BeppoSAX WFC and GRBM preliminary data
  34. GRB 010214: X-Ray afterglow
  35. GRB 010214 optical observation
  36. GRB010213, Radio Observations
  37. J-Band Observation of GRB 010214.
  38. GRB010213, Near-IR observations
  39. Possible InfraRed Transient of GRB 010214.
  40. GRB 010214, optical observations
  41. GRB010213 detected by HETE
  42. IPN Status Report
  43. HETE Status
  44. IPN/RXTE TRIANGULATION OF GRB010126
  45. GRB010126 Optical Observations
  46. IPN TRIANGULATION OF GRB010126
  47. Optical Observations of GRB 001018 at Keck
  48. IPN TRIANGULATION OF GRB010119 (SHORT/HARD)
  49. Optical observations of GRB 001018 with JCAM
  50. IPN TRIANGULATION OF GRB010115
  51. IPN TRIANGULATION OF GRB010109
  52. IPN TRIANGULATION OF GRB010109
  53. IPN triangulation of GRB010104
  54. IPN triangulation of GRB010103
  55. H band observation of GRB 001212
  56. IPN triangulation of GRB001219
  57. GRB 001212 Optical Observation
  58. GRB 001212 Optical Observation
  59. GRB 001212 possible OA in 2MASS
  60. IPN triangulation of GRB001212
  61. Confirmation of IPN position for GRB001204
  62. IPN triangulation of GRB001204 (short/hard)
  63. GRB001120, optical observations
  64. WSRT 4.8 GHz observations of GRB001109
  65. IPN triangulation of GRB001120
  66. GRB 001109: deep JHK upper limits
  67. GRB 001109 X-ray afterglow with BeppoSAX
  68. CORRECTION to XMM-Newton observation of GRB001025
  69. GRB001109, Radio observations
  70. GRB001105 BVRI field photometry correction
  71. GRB001105, BVRI field photometry
  72. IPN TRIANGULATION OF GRB001105
  73. GRB 001025B, Optical obervations
  74. GRB 991208: HST Imaging of the Host Galaxy
  75. GRB 001025B, I-band observations
  76. XMM-Newton observation of GRB001025
  77. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  78. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  79. GRB001007: Optical observations
  80. ASM Localization of GRB 001025
  81. GRB001007, Radio observations
  82. GRB 001018, Possible Radio Afterglow
  83. GRB001018, Gamma Ray Observations
  84. IPN TRIANGULATION OF GRB001019
  85. IPN TRIANGULATION OF GRB001018
  86. IPN TRIANGULATION OF GRB 001017
  87. V,R,I band observations of GRB000926
  88. HETE positions added to GCN
  89. GRB000926 - Amateur Optical Observations
  90. CONCAM null result on GRB001005
  91. IPN triangulation of GRB001005
  92. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  93. GRB000926 - Optical observations
  94. GRB000926 - Optical observations
  95. GRB 000926, Optical Decay
  96. GRB000911: VLT infrared observation
  97. GRB 000926, Optical Observations
  98. GRB000926 K'-band Observation
  99. J and K band observations of GRB 000926
  100. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.

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