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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"

32509 results found.

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

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