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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"

32504 results found.

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

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