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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"

36077 results found.

  1. GRB 000301C: K' Observations
  2. GRB000301C - Host galaxy not detected in R (?)
  3. GRB000301C optical observations
  4. GRB 000301c near-IR observations
  5. GRB 000301C, Optical Color
  6. GRB000301C, Optical Spectroscopy
  7. GRB 000301C, UBVRI field photometry
  8. GRB 000301C, Optical Observation
  9. GRB000301C 250 GHz detection
  10. GRB 000301C R-band observation
  11. GRB 000301C, Optical Observation
  12. GRB000301C, near-infrared observations (JHK' photometry)
  13. GRB 000301C: OT confirmed
  14. GRB000301c optical observations
  15. GRB 000301A, Radio Observations
  16. GRB000301C, optical observations
  17. GRB000301c, near-infrared observations
  18. GRB000301C
  19. GRB 000301C : Optical Candidate
  20. GRB000301C: RXTE/ASM and IPN localizations
  21. GRB000226 [IPN Position]
  22. HST Observations of GRB 990712
  23. GRB 000214 near-IR observations
  24. GRB 000115 Optical observations
  25. GRB 000214, Radio Observations
  26. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  27. GRB 000115, BVRI field photometry
  28. IPN annulus for GRB000214
  29. BATSE GRB trigger criterion changed
  30. GRB000210 X-ray afterglow
  31. GRB000214: X-ray afterglow candidate
  32. BeppoSAX GRB000214 ("S. Valentine's day GRB")
  33. GRB 000210: BATSE Observations
  34. Optical observations of the Chandra X-ray source for GRB000210
  35. Chandra Observations of GRB000210 X-ray Afterglow
  36. IPN triangulation of GRB000210
  37. GRB 000201: TAROT optical observations
  38. GRB 000131 Optical Observations
  39. GRB000126 Optical Observations
  40. BATSE GRB trigger criteria changed
  41. GRB 991208, radio observations
  42. BATSE+IPN location of GRB000131
  43. IPN localization of GRB000131
  44. GRB 000126, optical observations
  45. GRB000126, optical observations
  46. BATSE location of GRB000126
  47. IPN localization of GRB000126
  48. GRB 000115 Optical observations
  49. BATSE Observations of GRB000115
  50. Second RXTE Observation of GRB 000115
  51. GRB991216, UBVRIJHK field photometry
  52. Single IPN error box for GRB991229
  53. GRB 991216 VLBA Observations
  54. BEPPOSAX GRBM Localization of GRB991226
  55. IPN error boxes for GRB991229
  56. GRB 991216: J band spectrophotometry
  57. GRB 991216: Detection of the Host and/or Absorber Galaxy
  58. IPN localization of GRB991226
  59. Single IPN error box for GRB991221
  60. IPN error boxes for GRB991221
  61. GRB 991216 RXTE ASM Observations
  62. IPN error box for GRB991216
  63. GRB 991216: Updated BATSE parameters
  64. Lowell/Perkins observation of GRB 991216
  65. GRB 991217 (SAX J2303.2+0015) Optical observations
  66. Chandra observation of the X-ray afterglow of GRB991216
  67. GRB 991216, optical observations
  68. GRB 991216 Optical Observations
  69. GRB 991216 Optical spectroscopy/imaging
  70. VLT spectra of GRB991216
  71. K observations of GRB991216
  72. GRB 991217 (SAX J2303.2+0015) Optical observations
  73. GRB991216 Spectroscopy
  74. Lowell/Perkins observation of GRB 991216
  75. GRB991216, optical observations
  76. Refined IPN localization of GRB991216
  77. GRB 991216 Radio Observations
  78. GRB 991217
  79. GRB 991208 Keck Spectroscopy
  80. GRB 991208 Infrared Detection
  81. GRB 991216--Summary of RXTE Observations
  82. GRB 991216 Optical Observations
  83. GRB 991216, optical observations
  84. GRB 991208 SAO-RAS Spectroscopy
  85. SAX J2303.2+0015: an x-ray/GRB?
  86. GRB 991216, Optical Transient
  87. GRB 991216, Optical Afterglow
  88. GRB 991216: Comparison with DPOSS images
  89. GRB 991208 optical observations
  90. Lowell/Perkins observation of GRB 991216
  91. GRB 991216 Optical Observation
  92. GRB 991208 Keck Spectroscopy
  93. GRB 991216: Extremely bright BATSE burst
  94. GRB991208, optical observations
  95. GRB 991208 Keck Spectroscopy
  96. GRB991208 - millimeter detection
  97. GRB 991208, Optical Observation
  98. GRB 991208 - OVRO detection
  99. GRB 991208 Optical Decay
  100. GRB 991208 optical observations

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Download all Circulars as a .tar.gz archive (updated once a day):
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