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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"

31730 results found.

  1. GRB 000301C: K' Observations
  2. GRB000301C OT candidate optical observations
  3. Optical observations of GRB000301c
  4. GRB000301C, Radio observations
  5. GRB000301C, Radio observations
  6. GRB000301C, near-infrared observations (JHK' imaging)
  7. GRB 000301C, Optical Color
  8. GRB 000301C, UBVRI field photometry
  9. GRB 000301C, Optical Observation
  10. GRB000301C, optical observations
  11. GRB000301C 250 GHz detection
  12. GRB 000301C R-band observation
  13. GRB 000301C, Optical Observation
  14. GRB000301C, near-infrared observations (JHK' photometry)
  15. GRB 000301C: OT confirmed
  16. GRB000301c optical observations
  17. GRB 000301A, Radio Observations
  18. GRB000301C, optical observations
  19. GRB000301c, near-infrared observations
  20. GRB000301C
  21. GRB 000301C : Optical Candidate
  22. Radio observations of the error box of GRB000301A
  23. HST Observations of GRB 990712
  24. GRB 000115 Optical observations
  25. GRB 000214, Radio Observations
  26. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  27. GRB000210, Radio Observations
  28. Correction to GCN 557 (GRB000214: BeppoSAX GRBM and WFC Detection)
  29. IPN annulus for GRB000214
  30. Optical observations of GRB000210
  31. GRB000210 X-ray afterglow
  32. GRB 000210: BATSE Observations
  33. Correction to Chandra Position of GRB000210 afterglow
  34. Optical observations of the Chandra X-ray source for GRB000210
  35. GRB000210, Radio Observations
  36. Optical candidate for GRB000210
  37. Chandra Observations of GRB000210 X-ray Afterglow
  38. IPN triangulation of GRB000210
  39. GRB000201, Radio Observations
  40. Optical observations of GRB000131
  41. GRB000201 Optical Observations
  42. GRB 000131 Optical Observations
  43. GRB000126 Optical Observations
  44. GRB 991208, radio observations
  45. BATSE+IPN location of GRB000131
  46. GRB 000126, optical observations
  47. GRB000126, optical observations
  48. BATSE location of GRB000126
  49. GRB 000115 Optical observations
  50. BATSE Observations of GRB000115
  51. Correction to GCN 520 (IPN annulus for GRB000115)
  52. IPN annulus for GRB000115
  53. GRB991216, UBVRIJHK field photometry
  54. GRB991216 late optical observation
  55. Single IPN error box for GRB991229
  56. GCN resumes full operations
  57. GRB 991216 VLBA Observations
  58. BEPPOSAX GRBM Localization of GRB991226
  59. GRB 991216: J band spectrophotometry
  60. GRB 991216: Detection of the Host and/or Absorber Galaxy
  61. Single IPN error box for GRB991221
  62. GRB 991216 RXTE ASM Observations
  63. IPN error box for GRB991216
  64. Lowell/Perkins observation of GRB 991216
  65. GRB 991217 (SAX J2303.2+0015) Optical observations
  66. GRB991217/SAX J2303.2+0015, optical observations
  67. Chandra observation of the X-ray afterglow of GRB991216
  68. GRB 991216, optical observations
  69. GRB 991216 Optical Observations
  70. GRB 991216 Optical spectroscopy/imaging
  71. VLT spectra of GRB991216
  72. GRB991216 Optical and IR observations
  73. SAX J2303.2+0015 Optical observations
  74. IR observations of GRB991216
  75. GRB991216 radio observations
  76. GRB 991217 (SAX J2303.2+0015) Optical observations
  77. GRB991216 radio observations
  78. Lowell/Perkins observation of GRB 991216
  79. GRB991216, optical observations
  80. Refined IPN localization of GRB991216
  81. GRB 991216 Radio Observations
  82. GRB 991208 Keck Spectroscopy
  83. GRB 991208 Infrared Detection
  84. GRB991216
  85. GRB 991216--Summary of RXTE Observations
  86. GRB 991216 Optical Observations
  87. GRB 991216, optical observations
  88. GRB 991208 SAO-RAS Spectroscopy
  89. GRB 991216, Optical Transient
  90. GRB 991216, Optical Afterglow
  91. GRB991216 ('Beethoven Burst') B, R, and K Observations
  92. GRB 991216: Comparison with DPOSS images
  93. GRB 991208 optical observations
  94. Lowell/Perkins observation of GRB 991216
  95. GRB 991216 Optical Observation
  96. GRB 991208 Keck Spectroscopy
  97. R-band Observations of GRB991208 at TNG
  98. GRB991208, optical observations
  99. GRB 991208 Keck Spectroscopy
  100. GRB991208 - millimeter detection

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