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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"

32510 results found.

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

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