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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"

16161 results found.

  1. GRB010222: fading behavior
  2. GRB 010222 BV optical observations
  3. GRB010220, Optical Observations
  4. GRB010214 follow-up from Hanle
  5. GRB 010222: Near-IR Observations
  6. GRB 010222: Optical Observations
  7. GRB 010222, Decay Slope Confirmed
  8. GRB010222: Another absorption line system
  9. GRB010222: Optical decay slope
  10. GRB 010214, Optical Observations
  11. GRB010222: Sub-millimeter detection
  12. GRB010222: R-band fading behavior
  13. GRB010222: Optical Observations
  14. GRB010222, radio observations
  15. GRB010222, optical observations
  16. GRB010222: BeppoSAX/NFI Observations
  17. Redshift of the Optical Transient of GRB010222
  18. GRB010222: possible optical counterpart
  19. GRB010222
  20. GRB010220, Radio and Optical Observations
  21. GRB 010220, simultaneous optical observations
  22. GRB010214, candidate optical afterglow
  23. GRB010214, optical observations
  24. GRB 010214, Optical Observations
  25. GRB 010214 optical observation
  26. GRB010213 Optical Observation
  27. GRB010213, Radio Observations
  28. GRB010214, optical observations
  29. GRB010213, optical observations
  30. GRB010214 Optical Observation
  31. GRB 010214, optical observations
  32. GRB010213 detected by HETE
  33. HETE Status
  34. GRB010126: CONCAM crude optical limits during GRB
  35. GRB010126, TNG R-band observations
  36. GRB010126 Optical Observations
  37. GRB010126 optical observations
  38. GRB010126: Optical observations
  39. GRB 010119, optical observations
  40. GRB010119: Optical observations
  41. Optical Observations of GRB 001018 at Keck
  42. Optical observations of GRB 001018 with JCAM
  43. GRB010103, optical observations
  44. GRB 001212 Optical Observation
  45. GRB 001212 Optical Observation
  46. GRB 001212 optical observation
  47. GRB 001212 possible OA in 2MASS
  48. GRB 001212 possible OA
  49. GRB001204: Optical observations
  50. GRB 001105, further optical observations
  51. GRB001120: Gunn-i observations
  52. GRB001120: Optical observations
  53. GRB001109, optical observations
  54. GRB001120, optical observations
  55. Optical/NIR observations of GRB001109
  56. GRB 001109: deep JHK upper limits
  57. GRB001109: Optical observations
  58. GRB001109, R-band optical observations
  59. GRB001109, Radio observations
  60. GRB001105, BVRI field photometry
  61. GRB 001105, R-band observation
  62. GRB 001025B, Optical obervations
  63. GRB 991208: HST Imaging of the Host Galaxy
  64. GRB000926: R-image of the host galaxy
  65. GRB 001025 Optical Observations
  66. GRB 001025A, optical observation
  67. GRB001007: Optical observations
  68. GRB001007, Radio observations
  69. GRB001019, Optical Observations
  70. GRB 000926: Improved Absorber Redshift
  71. The Likely Optical/Infrared Afterglow of GRB 001011
  72. GRB 001007, BVR-band observations
  73. GRB000926 - Amateur Optical Observations
  74. GRB001007: Optical observations
  75. CONCAM null result on GRB001005
  76. GRB 000926 : the host galaxy
  77. GRB 000926 Chandra Observation
  78. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  79. GRB000926 - Optical observations
  80. GRB000926 - Optical observations
  81. GRB 000926, Optical Decay
  82. GRB000911: VLT infrared observation
  83. GRB000926 - Optical observations
  84. GRB000926 - Optical observations
  85. GRB 000926: optical observations
  86. GRB 000926, Optical Observations
  87. GRB000926 - Optical observations
  88. GRB000911: optical VLT observations
  89. GRB000926 K'-band Observation
  90. GRB000926 : increasing optical decay slope
  91. GRB000926 optical observations
  92. GRB000926 - Optical observations
  93. Re: GRB 000926, optical observation by Oksanen (vsnet-grb)
  94. J and K band observations of GRB 000926
  95. GRB000911 Optical Observations
  96. GRB 000926: Lightcurve Update and Predictions
  97. GRB 000926, optical observation by Oksanen (vsnet-grb)
  98. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  99. GRB000926: Optical observations
  100. CONCAM crude optical limits before and after GRB000926

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