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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"

32501 results found.

  1. GRB 010222: Near-IR Observations
  2. GRB 010222: Optical Observations
  3. GRB 010222, Decay Slope Confirmed
  4. GRB010222: Another absorption line system
  5. GRB010222: Optical decay slope
  6. GRB 010214, Optical Observations
  7. GRB010222: Sub-millimeter detection
  8. GRB010222: R-band fading behavior
  9. GRB010222: Optical Observations
  10. GRB010222, radio observations
  11. GRB010222, optical observations
  12. GRB010222: BeppoSAX/NFI Observations
  13. Redshift of the Optical Transient of GRB010222
  14. GRB010222: possible optical counterpart
  15. GRB010222
  16. GRB010222: BeppoSAX refined position
  17. ALERT: GRB010222: the brightest GRB observed by BeppoSAX
  18. GRB010220, Radio and Optical Observations
  19. GRB 010220, simultaneous optical observations
  20. GRB010220: BeppoSAX WFC and GRBM preliminary data
  21. GRB010214, candidate optical afterglow
  22. GRB010214, optical observations
  23. GRB010214: BeppoSAX WFC and GRBM preliminary data
  24. GRB 010214: X-Ray afterglow
  25. GRB 010214, Optical Observations
  26. GRB 010214 optical observation
  27. GRB010213, Radio Observations
  28. GRB010213 Optical Observation
  29. GRB010213, Radio Observations
  30. J-Band Observation of GRB 010214.
  31. GRB010214, Radio Observations
  32. GRB010214, optical observations
  33. GRB010213, optical observations
  34. Possible InfraRed Transient of GRB 010214.
  35. GRB010214 Optical Observation
  36. GRB010213 (HETE) TAROT observations
  37. GRB 010214, optical observations
  38. IPN Status Report
  39. HETE Status
  40. GRB010126 opt. obs.
  41. IPN/RXTE TRIANGULATION OF GRB010126
  42. GRB010126: CONCAM crude optical limits during GRB
  43. GRB010126, TNG R-band observations
  44. GRB010126 Optical Observations
  45. GRB010126 optical observations
  46. GRB010126: Optical observations
  47. IPN/RXTE TRIANGULATION OF GRB010126
  48. GRB 010119, optical observations
  49. GRB010119: Optical observations
  50. Optical Observations of GRB 001018 at Keck
  51. GRB010119, Radio observations
  52. Optical observations of GRB 001018 with JCAM
  53. IPN TRIANGULATION OF GRB010109
  54. GRB 001204: Ks observations
  55. H band observation of GRB 001212
  56. GRB 001212 Optical Observation
  57. GRB 001212 Optical Observation
  58. GRB 001212 optical observation
  59. GRB 001212 possible OA in 2MASS
  60. GRB 001212 possible OA
  61. GRB001204: Optical observations
  62. Confirmation of IPN position for GRB001204
  63. GRB001204, Radio observations
  64. GRB 001105, further optical observations
  65. GRB001120: Gunn-i observations
  66. GRB001109, optical observations
  67. WSRT 4.8 GHz observations of GRB001109
  68. Optical/NIR observations of GRB001109
  69. GRB 001109: deep JHK upper limits
  70. GRB 001109 X-ray afterglow with BeppoSAX
  71. CORRECTION to XMM-Newton observation of GRB001025
  72. GRB001109: Optical observations
  73. GRB001109, R-band optical observations
  74. GRB001109, Radio observations
  75. GRB001105 BVRI field photometry correction
  76. GRB001105, BVRI field photometry
  77. GRB 001105, R-band observation
  78. GRB 991208: HST Imaging of the Host Galaxy
  79. GRB000926: R-image of the host galaxy
  80. GRB 001025B, I-band observations
  81. XMM-Newton observation of GRB001025
  82. GRB001025B, Radio observations
  83. GRB 001025 Optical Observations
  84. GRB 001025A, optical observation
  85. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  86. IPN triangulation of GRB001025
  87. GRB001007: Optical observations
  88. GRB001007, Radio observations
  89. GRB 001018, Possible Radio Afterglow
  90. CORRECTION TO PEAK FLUX OF GRB001018
  91. GRB 000926: Improved Absorber Redshift
  92. V,R,I band observations of GRB000926
  93. The Likely Optical/Infrared Afterglow of GRB 001011
  94. HETE positions added to GCN
  95. GRB 001007, BVR-band observations
  96. GRB001007: Optical observations
  97. CONCAM null result on GRB001005
  98. GRB 000926 : the host galaxy
  99. GRB 000926 Chandra Observation
  100. Public availability of BeppoSAX data of GRB000926

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