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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"

40744 results found.

  1. GRB000301c - R photometry and nearby faint source confirmation
  2. GRB 000301C, Optical Observation
  3. GRB 000301C Optical Observations
  4. GRB 000301C: K' Observations
  5. GRB000301C OT candidate optical observations
  6. GRB000301C - Host galaxy not detected in R (?)
  7. Optical observations of GRB000301c
  8. GRB000301C, Radio observations
  9. GRB000301C, Radio observations
  10. GRB000301C optical observations
  11. GRB000301C, near-infrared observations (JHK' imaging)
  12. GRB 000301c near-IR observations
  13. GRB 000301C, Optical Color
  14. GRB 000301C, UBVRI field photometry
  15. GRB 000301C, Optical Observation
  16. GRB000301C, optical observations
  17. GRB000301C 250 GHz detection
  18. GRB 000301C R-band observation
  19. GRB 000301C, Optical Observation
  20. GRB000301C, near-infrared observations (JHK' photometry)
  21. GRB 000301C: OT confirmed
  22. GRB000301c optical observations
  23. GRB 000301A, Radio Observations
  24. GRB000301C, optical observations
  25. GRB000301c, near-infrared observations
  26. GRB000301C
  27. GRB 000301C : Optical Candidate
  28. Radio observations of the error box of GRB000301A
  29. GRB000301C: RXTE/ASM and IPN localizations
  30. HST Observations of GRB 990712
  31. GRB 000214 near-IR observations
  32. GRB 000115 Optical observations
  33. GRB 000214, Radio Observations
  34. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  35. GRB000210, Radio Observations
  36. Correction to GCN 557 (GRB000214: BeppoSAX GRBM and WFC Detection)
  37. GRB 000115, BVRI field photometry
  38. GRB000214: BeppoSAX GRBM and WFC Detection
  39. IPN annulus for GRB000214
  40. BATSE GRB trigger criterion changed
  41. Optical observations of GRB000210
  42. GRB000210 X-ray afterglow
  43. BeppoSAX GRB000214 ("S. Valentine's day GRB")
  44. GRB 000210: BATSE Observations
  45. Correction to Chandra Position of GRB000210 afterglow
  46. Optical observations of the Chandra X-ray source for GRB000210
  47. GRB000210, Radio Observations
  48. Optical candidate for GRB000210
  49. Chandra Observations of GRB000210 X-ray Afterglow
  50. IPN triangulation of GRB000210
  51. GRB000201, Radio Observations
  52. GRB000210: BeppoSAX GRBM and WFC Detection
  53. Optical observations of GRB000131
  54. GRB000201 Optical Observations
  55. GRB 000201: TAROT optical observations
  56. GRB 000131 Optical Observations
  57. GRB000126 Optical Observations
  58. BATSE GRB trigger criteria changed
  59. GRB 991208, radio observations
  60. BATSE+IPN location of GRB000131
  61. GRB 000126, optical observations
  62. GRB000126, optical observations
  63. BATSE location of GRB000126
  64. IPN localization of GRB000126
  65. GRB 000115 Optical observations
  66. BATSE Observations of GRB000115
  67. Correction to GCN 520 (IPN annulus for GRB000115)
  68. IPN annulus for GRB000115
  69. Second RXTE Observation of GRB 000115
  70. GRB991216, UBVRIJHK field photometry
  71. GRB991216 late optical observation
  72. Single IPN error box for GRB991229
  73. GCN resumes full operations
  74. GRB 991216 VLBA Observations
  75. BEPPOSAX GRBM Localization of GRB991226
  76. GRB 991216: J band spectrophotometry
  77. GRB 991216: Detection of the Host and/or Absorber Galaxy
  78. Single IPN error box for GRB991221
  79. GRB 991216 RXTE ASM Observations
  80. IPN error box for GRB991216
  81. GRB 991216: Updated BATSE parameters
  82. Lowell/Perkins observation of GRB 991216
  83. GRB 991217 (SAX J2303.2+0015) Optical observations
  84. GRB991217/SAX J2303.2+0015, optical observations
  85. Chandra observation of the X-ray afterglow of GRB991216
  86. GRB 991216, optical observations
  87. GRB 991216 Optical Observations
  88. GRB 991216 Optical spectroscopy/imaging
  89. VLT spectra of GRB991216
  90. GRB991216 Optical and IR observations
  91. K observations of GRB991216
  92. SAX J2303.2+0015 Optical observations
  93. IR observations of GRB991216
  94. GRB991216 radio observations
  95. GRB 991217 (SAX J2303.2+0015) Optical observations
  96. GRB991216 radio observations
  97. Lowell/Perkins observation of GRB 991216
  98. GRB991216, optical observations
  99. GRB991216 Optical and infrared observations of Beethoven Burst
  100. Refined IPN localization of GRB991216

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