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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"

26277 results found.

  1. IPN TRIANGULATION OF GRB010126
  2. Optical Observations of GRB 001018 at Keck
  3. IPN TRIANGULATION OF GRB010119 (SHORT/HARD)
  4. Optical observations of GRB 001018 with JCAM
  5. IPN TRIANGULATION OF GRB010115
  6. IPN TRIANGULATION OF GRB010109
  7. IPN TRIANGULATION OF GRB010109
  8. IPN triangulation of GRB010104
  9. IPN triangulation of GRB010103
  10. H band observation of GRB 001212
  11. IPN triangulation of GRB001219
  12. GRB 001212 Optical Observation
  13. GRB 001212 Optical Observation
  14. GRB 001212 possible OA in 2MASS
  15. IPN triangulation of GRB001212
  16. Confirmation of IPN position for GRB001204
  17. IPN triangulation of GRB001204 (short/hard)
  18. GRB001120, optical observations
  19. WSRT 4.8 GHz observations of GRB001109
  20. IPN triangulation of GRB001120
  21. GRB 001109: deep JHK upper limits
  22. GRB 001109 X-ray afterglow with BeppoSAX
  23. CORRECTION to XMM-Newton observation of GRB001025
  24. GRB001109, Radio observations
  25. GRB001105 BVRI field photometry correction
  26. GRB001105, BVRI field photometry
  27. IPN TRIANGULATION OF GRB001105
  28. GRB 001025B, Optical obervations
  29. GRB 991208: HST Imaging of the Host Galaxy
  30. GRB 001025B, I-band observations
  31. XMM-Newton observation of GRB001025
  32. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  33. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  34. GRB001007: Optical observations
  35. ASM Localization of GRB 001025
  36. GRB001007, Radio observations
  37. GRB 001018, Possible Radio Afterglow
  38. GRB001018, Gamma Ray Observations
  39. IPN TRIANGULATION OF GRB001019
  40. IPN TRIANGULATION OF GRB001018
  41. IPN TRIANGULATION OF GRB 001017
  42. V,R,I band observations of GRB000926
  43. HETE positions added to GCN
  44. GRB000926 - Amateur Optical Observations
  45. CONCAM null result on GRB001005
  46. IPN triangulation of GRB001005
  47. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  48. GRB000926 - Optical observations
  49. GRB000926 - Optical observations
  50. GRB 000926, Optical Decay
  51. GRB000911: VLT infrared observation
  52. GRB 000926, Optical Observations
  53. GRB000926 K'-band Observation
  54. J and K band observations of GRB 000926
  55. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  56. CONCAM crude optical limits before and after GRB000926
  57. GRB 000926: Preliminary R-band Lightcurve
  58. Spectroscopic Redshift of GRB 000926
  59. GRB 000926: Optical candidate
  60. Optical candidate for GRB000926
  61. GRB 000911, BVRI field photometry
  62. GRB000911, Radio and Optical observations
  63. GRB000911: Optical observations
  64. GRB000830, BVRI field photometry
  65. GRB000210, Optical observations
  66. "Snapshot" afterglow IDs and GRB 000830
  67. GRB000730, Gamma Ray Observations
  68. GRB000812, Radio observations
  69. GRB000801, Gamma Ray Observations
  70. GRB000801, VLT-Antu R-band observations
  71. GRB 991208 Host Galaxy Imaging
  72. IPN localization of GRB000730B
  73. GRB 990510: Possible detection of a host galaxy
  74. GRB 990510 Host Galaxy Discovery
  75. IPN localization of GRB000727
  76. GRB 990712: Late time HST/STIS Observations
  77. GRB 991216, HST/STIS observations
  78. GRB000620, Radio Observations
  79. GRB000630, optical observations
  80. GRB000630, Revised BVRI Field Photometry
  81. GRB000630, Optical Observations
  82. GRB000630, optical observations
  83. GRB000630, optical observations
  84. GRB000630, BVRI Field Photometry
  85. GRB000630, optical observations
  86. GRB000630: Optical observations
  87. GRB000630, Radio Observations
  88. possible optical counterpart of GRB 000630
  89. GRB 000620, optical observations
  90. GRB000418, HST/STIS Observations
  91. GRB990123: Late-time HST/STIS observations of the host
  92. GRB000620, optical observations
  93. GRB000615: H-band observations
  94. GRB990308, HST/STIS observations of the host galaxy
  95. GRB000620 - Optical observations
  96. GRB000620 Optical observations
  97. GRB000620: BeppoSAX WFC and GRBM detection
  98. GRB000607, optical observations
  99. GRB 000615: NIR further observations
  100. GRB990123, HST/STIS observations of the host galaxy

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