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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"

25984 results found.

  1. Possible InfraRed Transient of GRB 010214.
  2. GRB 010214, optical observations
  3. GRB010213 detected by HETE
  4. IPN Status Report
  5. HETE Status
  6. IPN/RXTE TRIANGULATION OF GRB010126
  7. GRB010126 Optical Observations
  8. IPN TRIANGULATION OF GRB010126
  9. Optical Observations of GRB 001018 at Keck
  10. IPN TRIANGULATION OF GRB010119 (SHORT/HARD)
  11. Optical observations of GRB 001018 with JCAM
  12. IPN TRIANGULATION OF GRB010115
  13. IPN TRIANGULATION OF GRB010109
  14. IPN TRIANGULATION OF GRB010109
  15. IPN triangulation of GRB010104
  16. IPN triangulation of GRB010103
  17. H band observation of GRB 001212
  18. IPN triangulation of GRB001219
  19. GRB 001212 Optical Observation
  20. GRB 001212 Optical Observation
  21. GRB 001212 possible OA in 2MASS
  22. IPN triangulation of GRB001212
  23. Confirmation of IPN position for GRB001204
  24. IPN triangulation of GRB001204 (short/hard)
  25. GRB001120, optical observations
  26. WSRT 4.8 GHz observations of GRB001109
  27. IPN triangulation of GRB001120
  28. GRB 001109: deep JHK upper limits
  29. GRB 001109 X-ray afterglow with BeppoSAX
  30. CORRECTION to XMM-Newton observation of GRB001025
  31. GRB001109, Radio observations
  32. GRB001105 BVRI field photometry correction
  33. GRB001105, BVRI field photometry
  34. IPN TRIANGULATION OF GRB001105
  35. GRB 001025B, Optical obervations
  36. GRB 991208: HST Imaging of the Host Galaxy
  37. GRB 001025B, I-band observations
  38. XMM-Newton observation of GRB001025
  39. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  40. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  41. GRB001007: Optical observations
  42. ASM Localization of GRB 001025
  43. GRB001007, Radio observations
  44. GRB 001018, Possible Radio Afterglow
  45. GRB001018, Gamma Ray Observations
  46. IPN TRIANGULATION OF GRB001019
  47. IPN TRIANGULATION OF GRB001018
  48. IPN TRIANGULATION OF GRB 001017
  49. V,R,I band observations of GRB000926
  50. HETE positions added to GCN
  51. GRB000926 - Amateur Optical Observations
  52. CONCAM null result on GRB001005
  53. IPN triangulation of GRB001005
  54. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  55. GRB000926 - Optical observations
  56. GRB000926 - Optical observations
  57. GRB 000926, Optical Decay
  58. GRB000911: VLT infrared observation
  59. GRB 000926, Optical Observations
  60. GRB000926 K'-band Observation
  61. J and K band observations of GRB 000926
  62. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  63. CONCAM crude optical limits before and after GRB000926
  64. GRB 000926: Preliminary R-band Lightcurve
  65. Spectroscopic Redshift of GRB 000926
  66. GRB 000926: Optical candidate
  67. Optical candidate for GRB000926
  68. GRB 000911, BVRI field photometry
  69. GRB000911, Radio and Optical observations
  70. GRB000911: Optical observations
  71. GRB000830, BVRI field photometry
  72. GRB000210, Optical observations
  73. "Snapshot" afterglow IDs and GRB 000830
  74. GRB000730, Gamma Ray Observations
  75. GRB000812, Radio observations
  76. GRB000801, Gamma Ray Observations
  77. GRB000801, VLT-Antu R-band observations
  78. GRB 991208 Host Galaxy Imaging
  79. IPN localization of GRB000730B
  80. GRB 990510: Possible detection of a host galaxy
  81. GRB 990510 Host Galaxy Discovery
  82. IPN localization of GRB000727
  83. GRB 990712: Late time HST/STIS Observations
  84. GRB 991216, HST/STIS observations
  85. GRB000620, Radio Observations
  86. GRB000630, optical observations
  87. GRB000630, Revised BVRI Field Photometry
  88. GRB000630, Optical Observations
  89. GRB000630, optical observations
  90. GRB000630, optical observations
  91. GRB000630, BVRI Field Photometry
  92. GRB000630, optical observations
  93. GRB000630: Optical observations
  94. GRB000630, Radio Observations
  95. possible optical counterpart of GRB 000630
  96. GRB 000620, optical observations
  97. GRB000418, HST/STIS Observations
  98. GRB990123: Late-time HST/STIS observations of the host
  99. GRB000620, optical observations
  100. GRB000615: H-band observations

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