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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"

40638 results found.

  1. GRB000301C - B and R photometry
  2. GRB000301C - R photometry
  3. GRB 000307, Optical Observations
  4. GRB 000307, BVRI Field Photometry
  5. GRB 000301C: Optical Spectrum and Redshift
  6. GRB 000301C: Optical Spectrum and Redshift
  7. GRB 000301C: A Precise Redshift Determination
  8. GRB 000301C: HST/STIS-PRISM NUV-MAMA spectroscopy
  9. GRB 000301C: HST/STIS CCD Imaging of the field
  10. GRB 000301c: K' observations
  11. GRB000301C, optical R-band observations
  12. GRB000301c - R photometry and nearby faint source confirmation
  13. GRB 000301C, Optical Observation
  14. GRB 000301c: K' observations
  15. GRB 000301C Optical Observations
  16. GRB 000301C: K' Observations
  17. GRB000301C OT candidate optical observations
  18. GRB000301C - Host galaxy not detected in R (?)
  19. Optical observations of GRB000301c
  20. GRB000301C, Radio observations
  21. GRB000301C, Radio observations
  22. GRB000301C optical observations
  23. GRB000301C, near-infrared observations (JHK' imaging)
  24. GRB 000301c near-IR observations
  25. GRB 000301C, Optical Color
  26. GRB000301C, Optical Spectroscopy
  27. GRB 000301C, UBVRI field photometry
  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. HST Observations of GRB 990712
  43. GRB 000214 near-IR observations
  44. GRB 000115 Optical observations
  45. GRB 000214, Radio Observations
  46. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  47. GRB000210, Radio Observations
  48. GRB 000115, BVRI field photometry
  49. GRB000214: BeppoSAX GRBM and WFC Detection
  50. IPN annulus for GRB000214
  51. Optical observations of GRB000210
  52. GRB000210 X-ray afterglow
  53. GRB000214: X-ray afterglow candidate
  54. GRB000214 refined BeppoSAX-WFC position
  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. GRB 991208, radio observations
  71. BATSE+IPN location of GRB000131
  72. GRB 000126, optical observations
  73. GRB000126, optical observations
  74. BATSE location of GRB000126
  75. GRB 000115 Optical observations
  76. BATSE Observations of GRB000115
  77. IPN annulus for GRB000115
  78. GRB991216, UBVRIJHK field photometry
  79. GRB991216 late optical observation
  80. GCN resumes full operations
  81. GRB 991216 VLBA Observations
  82. IPN error boxes for GRB991229
  83. GRB 991216: J band spectrophotometry
  84. GRB 991216: Detection of the Host and/or Absorber Galaxy
  85. GRB 991216 RXTE ASM Observations
  86. Lowell/Perkins observation of GRB 991216
  87. GRB 991217 (SAX J2303.2+0015) Optical observations
  88. GRB991217/SAX J2303.2+0015, optical observations
  89. Chandra observation of the X-ray afterglow of GRB991216
  90. GRB 991216, optical observations
  91. GRB 991216 Optical Observations
  92. GRB 991216 Optical spectroscopy/imaging
  93. VLT spectra of GRB991216
  94. GRB991216 Optical and IR observations
  95. K observations of GRB991216
  96. SAX J2303.2+0015 Optical observations
  97. IR observations of GRB991216
  98. GRB991216 radio observations
  99. GRB 991217 (SAX J2303.2+0015) Optical observations
  100. GRB991216 radio observations

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