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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"

25751 results found.

  1. GRB000508B, BVR field photometry
  2. Possible GRB-related phenomenon
  3. RXTE/ASM and IPN localization of GRB 000508B
  4. GRB000424, UBVRI field photometry
  5. GRB000418, UBVRI field photometry update
  6. GRB000424, optical observations
  7. GRB 000429, optical observation
  8. GRB 000429, UBVRI field photometry
  9. GRB 000418, UBVRI field photometry
  10. GRB 000418, optical observation
  11. GRB 000418, Optical Observation
  12. GRB000418, near-infrared observations
  13. Correction to IPN error box for GRB000419
  14. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  15. GRB000416 BRJK observations
  16. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  17. GRB 000408, optical observations
  18. GRB 991208, UBVRI field photometry
  19. GRB000408, lotis optical observations
  20. GRB 000301C: Late-Time HST/STIS CCD Imaging of the field
  21. GRB000301C - Addendum to GCN 623
  22. GRB 000323, optical observations
  23. GRB 000326: Optical Observations
  24. GRB000326, Radio observations
  25. GRB000313, Radio observations
  26. GRB 000313 - optical transient in the BATSE error box
  27. GRB 000307, Optical Observations
  28. GRB 000307, BVRI Field Photometry
  29. GRB 000301C: A Precise Redshift Determination
  30. GRB 000301C, Optical Observation
  31. GRB 000301C: HST/STIS CCD Imaging of the field
  32. IPN error box for GRB000307
  33. GRB000301C, optical R-band observations
  34. GRB 000301C Optical Observations
  35. GRB 000301C: K' Observations
  36. GRB000301C OT candidate optical observations
  37. GRB000301C - Host galaxy not detected in R (?)
  38. Optical observations of GRB000301c
  39. GRB000301C, Radio observations
  40. GRB000301C, Radio observations
  41. GRB000301C, near-infrared observations (JHK' imaging)
  42. GRB 000301c near-IR observations
  43. GRB 000301C, UBVRI field photometry
  44. GRB 000301C: OT confirmed
  45. GRB000301c optical observations
  46. GRB000301C, optical observations
  47. GRB000301C
  48. GRB 000301C : Optical Candidate
  49. GRB000301C: RXTE/ASM and IPN localizations
  50. GRB000226 [IPN Position]
  51. HST Observations of GRB 990712
  52. GRB 000214 near-IR observations
  53. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  54. GRB000210, Radio Observations
  55. GRB 000115, BVRI field photometry
  56. GRB000214: BeppoSAX GRBM and WFC Detection
  57. Optical observations of GRB000210
  58. GRB000210 X-ray afterglow
  59. GRB000214: X-ray afterglow candidate
  60. GRB000214 refined BeppoSAX-WFC position
  61. GRB 000210: BATSE Observations
  62. Optical observations of the Chandra X-ray source for GRB000210
  63. GRB000210, Radio Observations
  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. SAX_WFC_GRB_NOTICE
  69. SAX_WFC_GRB_NOTICE
  70. GRB000201 Optical Observations
  71. GRB 000201: TAROT optical observations
  72. GRB 991208, radio observations
  73. BATSE+IPN location of GRB000131
  74. IPN localization of GRB000131
  75. GRB 000126, optical observations
  76. BATSE Observations of GRB000115
  77. Second RXTE Observation of GRB 000115
  78. GRB991216, UBVRIJHK field photometry
  79. GCN resumes full operations
  80. GRB 991216 VLBA Observations
  81. GRB 991216: J band spectrophotometry
  82. GRB 991216: Detection of the Host and/or Absorber Galaxy
  83. IPN localization of GRB991226
  84. GRB 991216 RXTE ASM Observations
  85. GRB 991216: Updated BATSE parameters
  86. GRB 991217 (SAX J2303.2+0015) Optical observations
  87. Chandra observation of the X-ray afterglow of GRB991216
  88. GRB 991216, optical observations
  89. GRB 991216 Optical spectroscopy/imaging
  90. SAX J2303.2+0015 Optical observations
  91. IR observations of GRB991216
  92. GRB 991217 (SAX J2303.2+0015) Optical observations
  93. GRB991216 Optical and infrared observations of Beethoven Burst
  94. GRB 991216 Radio Observations
  95. GRB 991208 Keck Spectroscopy
  96. GRB 991208 Infrared Detection
  97. GRB991216
  98. GRB 991216--Summary of RXTE Observations
  99. GRB 991216 Optical Observations
  100. GRB 991216, optical observations

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