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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"

42572 results found.

  1. GRB 000301C: Optical Spectrum and Redshift
  2. GRB 000301C: A Precise Redshift Determination
  3. GRB 000301C, Optical Observation
  4. GRB 000301C: HST/STIS-PRISM NUV-MAMA spectroscopy
  5. GRB 000301C: HST/STIS CCD Imaging of the field
  6. IPN error box for GRB000307
  7. GRB 000301c: K' observations
  8. GRB000301C, optical R-band observations
  9. GRB000301c - R photometry and nearby faint source confirmation
  10. GRB 000301C, Optical Observation
  11. GRB 000301c: K' observations
  12. GRB 000301C Optical Observations
  13. GRB 000301C: K' Observations
  14. GRB000301C OT candidate optical observations
  15. GRB000301C - Host galaxy not detected in R (?)
  16. Optical observations of GRB000301c
  17. GRB000301C, Radio observations
  18. GRB000301C, Radio observations
  19. GRB000301C optical observations
  20. GRB000301C, near-infrared observations (JHK' imaging)
  21. GRB 000301c near-IR observations
  22. GRB 000301C, Optical Color
  23. GRB000301C, Optical Spectroscopy
  24. GRB 000301C, UBVRI field photometry
  25. GRB 000301C, Optical Observation
  26. GRB000301C, optical observations
  27. GRB000301C 250 GHz detection
  28. GRB 000301C R-band observation
  29. GRB 000301C, Optical Observation
  30. GRB000301C, near-infrared observations (JHK' photometry)
  31. GRB 000301C: OT confirmed
  32. GRB000301c optical observations
  33. GRB 000301A, Radio Observations
  34. GRB000301C, optical observations
  35. GRB000301c, near-infrared observations
  36. GRB000301C
  37. GRB 000301C : Optical Candidate
  38. Radio observations of the error box of GRB000301A
  39. GRB000301C: RXTE/ASM and IPN localizations
  40. GRB000226 [IPN Position]
  41. HST Observations of GRB 990712
  42. GRB 000214 near-IR observations
  43. GRB 000115 Optical observations
  44. GRB 000214, Radio Observations
  45. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  46. GRB000210, Radio Observations
  47. GRB 000115, BVRI field photometry
  48. GRB000214: BeppoSAX GRBM and WFC Detection
  49. IPN annulus for GRB000214
  50. Optical observations of GRB000210
  51. GRB000210 X-ray afterglow
  52. GRB000214: X-ray afterglow candidate
  53. GRB000214 refined BeppoSAX-WFC position
  54. BeppoSAX GRB000214 ("S. Valentine's day GRB")
  55. GRB 000210: BATSE Observations
  56. Correction to Chandra Position of GRB000210 afterglow
  57. Optical observations of the Chandra X-ray source for GRB000210
  58. GRB000210, Radio Observations
  59. Optical candidate for GRB000210
  60. Chandra Observations of GRB000210 X-ray Afterglow
  61. IPN triangulation of GRB000210
  62. GRB000210: possible afterglow detection with BeppoSAX NFI
  63. GRB000201, Radio Observations
  64. GRB000210: BeppoSAX GRBM and WFC Detection
  65. Optical observations of GRB000131
  66. GRB000201 Optical Observations
  67. GRB 000201: TAROT optical observations
  68. GRB 000131 Optical Observations
  69. GRB000126 Optical Observations
  70. BATSE GRB trigger criteria changed
  71. GRB 991208, radio observations
  72. BATSE+IPN location of GRB000131
  73. IPN localization of GRB000131
  74. GRB000126, optical observations
  75. BATSE location of GRB000126
  76. IPN localization of GRB000126
  77. GRB 000115 Optical observations
  78. BATSE Observations of GRB000115
  79. Correction to GCN 520 (IPN annulus for GRB000115)
  80. IPN annulus for GRB000115
  81. Second RXTE Observation of GRB 000115
  82. GRB991216, UBVRIJHK field photometry
  83. GRB991216 late optical observation
  84. GCN resumes full operations
  85. GRB 991216 VLBA Observations
  86. BEPPOSAX GRBM Localization of GRB991226
  87. IPN error boxes for GRB991229
  88. GRB 991216: J band spectrophotometry
  89. GRB 991216: Detection of the Host and/or Absorber Galaxy
  90. IPN localization of GRB991226
  91. IPN error boxes for GRB991221
  92. GRB 991216 RXTE ASM Observations
  93. IPN error box for GRB991216
  94. Lowell/Perkins observation of GRB 991216
  95. GRB 991217 (SAX J2303.2+0015) Optical observations
  96. GRB991217/SAX J2303.2+0015, optical observations
  97. Chandra observation of the X-ray afterglow of GRB991216
  98. GRB 991216, optical observations
  99. GRB 991216 Optical Observations
  100. GRB 991216 Optical spectroscopy/imaging

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