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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"

16159 results found.

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

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