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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"

44399 results found.

  1. GRB 000307, BVRI Field Photometry
  2. GRB 000301C: Optical Spectrum and Redshift
  3. GRB 000301C: Optical Spectrum and Redshift
  4. GRB 000301C: A Precise Redshift Determination
  5. GRB 000301C, Optical Observation
  6. GRB 000301C: HST/STIS-PRISM NUV-MAMA spectroscopy
  7. GRB 000301C: HST/STIS CCD Imaging of the field
  8. IPN error box for GRB000307
  9. GRB 000301c: K' observations
  10. GRB000301C, optical R-band observations
  11. GRB000301c - R photometry and nearby faint source confirmation
  12. GRB 000301C, Optical Observation
  13. GRB 000301c: K' observations
  14. GRB 000301C Optical Observations
  15. GRB 000301C: K' Observations
  16. GRB000301C OT candidate optical observations
  17. GRB000301C - Host galaxy not detected in R (?)
  18. Optical observations of GRB000301c
  19. GRB000301C, Radio observations
  20. GRB000301C, Radio observations
  21. GRB000301C optical observations
  22. GRB000301C, near-infrared observations (JHK' imaging)
  23. GRB 000301c near-IR observations
  24. GRB 000301C, Optical Color
  25. GRB000301C, Optical Spectroscopy
  26. GRB 000301C, UBVRI field photometry
  27. GRB 000301C, Optical Observation
  28. GRB000301C, optical observations
  29. GRB000301C 250 GHz detection
  30. GRB 000301C R-band observation
  31. GRB 000301C, Optical Observation
  32. GRB000301C, near-infrared observations (JHK' photometry)
  33. GRB 000301C: OT confirmed
  34. GRB000301c optical observations
  35. GRB 000301A, Radio Observations
  36. GRB000301C, optical observations
  37. GRB000301c, near-infrared observations
  38. GRB000301C
  39. GRB 000301C : Optical Candidate
  40. Radio observations of the error box of GRB000301A
  41. GRB000301C: RXTE/ASM and IPN localizations
  42. GRB000226 [IPN Position]
  43. HST Observations of GRB 990712
  44. GRB 000214 near-IR observations
  45. GRB 000115 Optical observations
  46. GRB 000214, Radio Observations
  47. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  48. GRB000210, Radio Observations
  49. Correction to GCN 557 (GRB000214: BeppoSAX GRBM and WFC Detection)
  50. GRB 000115, BVRI field photometry
  51. GRB000214: BeppoSAX GRBM and WFC Detection
  52. IPN annulus for GRB000214
  53. Optical observations of GRB000210
  54. GRB000210 X-ray afterglow
  55. GRB000214: X-ray afterglow candidate
  56. GRB000214 refined BeppoSAX-WFC position
  57. BeppoSAX GRB000214 ("S. Valentine's day GRB")
  58. GRB 000210: BATSE Observations
  59. Correction to Chandra Position of GRB000210 afterglow
  60. Optical observations of the Chandra X-ray source for GRB000210
  61. GRB000210, Radio Observations
  62. Optical candidate for GRB000210
  63. Chandra Observations of GRB000210 X-ray Afterglow
  64. IPN triangulation of GRB000210
  65. GRB000210: possible afterglow detection with BeppoSAX NFI
  66. GRB000201, Radio Observations
  67. GRB000210: BeppoSAX GRBM and WFC Detection
  68. Optical observations of GRB000131
  69. GRB000201 Optical Observations
  70. GRB 000201: TAROT optical observations
  71. GRB 000131 Optical Observations
  72. GRB000126 Optical Observations
  73. GRB 991208, radio observations
  74. BATSE+IPN location of GRB000131
  75. IPN localization of GRB000131
  76. GRB 000126, optical observations
  77. GRB000126, optical observations
  78. BATSE location of GRB000126
  79. IPN localization of GRB000126
  80. GRB 000115 Optical observations
  81. BATSE Observations of GRB000115
  82. Correction to GCN 520 (IPN annulus for GRB000115)
  83. Second RXTE Observation of GRB 000115
  84. GRB991216, UBVRIJHK field photometry
  85. GRB991216 late optical observation
  86. Single IPN error box for GRB991229
  87. GCN resumes full operations
  88. GRB 991216 VLBA Observations
  89. BEPPOSAX GRBM Localization of GRB991226
  90. IPN error boxes for GRB991229
  91. GRB 991216: J band spectrophotometry
  92. GRB 991216: Detection of the Host and/or Absorber Galaxy
  93. IPN localization of GRB991226
  94. Single IPN error box for GRB991221
  95. IPN error boxes for GRB991221
  96. GRB 991216 RXTE ASM Observations
  97. IPN error box for GRB991216
  98. GRB 991216: Updated BATSE parameters
  99. Lowell/Perkins observation of GRB 991216
  100. GRB 991217 (SAX J2303.2+0015) Optical observations

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