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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"

26364 results found.

  1. GRB000604, optical observations
  2. GRB000528, optical observations at ESO
  3. GRB 000604 optical observations
  4. GRB 000418: Detection of the Host Galaxy
  5. GRB000604, optical observations, comparison with DPOSS
  6. GRB000528, Radio Observations
  7. X-ray Afterglow of GRB 000529
  8. GRB000529: BeppoSAX NFI follow-up preliminary analysis
  9. GRB000528: BeppoSAX NFI follow-up preliminary analysis
  10. GRB 000528 - WFC measurements
  11. GRB000519, BVRI field photometry
  12. IPN triangulation of GRB000519
  13. GRB000508B, optical photometry
  14. GRB000508B, BVR field photometry
  15. Possible GRB-related phenomenon
  16. RXTE/ASM and IPN localization of GRB 000508B
  17. GRB000424, UBVRI field photometry
  18. GRB000418, UBVRI field photometry update
  19. GRB000424, optical observations
  20. GRB 000429, optical observation
  21. GRB 000429, UBVRI field photometry
  22. GRB 000418, UBVRI field photometry
  23. GRB 000418, optical observation
  24. GRB 000418, Optical Observation
  25. GRB000418, near-infrared observations
  26. Correction to IPN error box for GRB000419
  27. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  28. GRB000416 BRJK observations
  29. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  30. GRB 000408, optical observations
  31. GRB 991208, UBVRI field photometry
  32. GRB000408, lotis optical observations
  33. GRB 000301C: Late-Time HST/STIS CCD Imaging of the field
  34. GRB000301C - Addendum to GCN 623
  35. GRB 000323, optical observations
  36. GRB 000326: Optical Observations
  37. GRB000326, Radio observations
  38. GRB000313, Radio observations
  39. GRB 000313 - optical transient in the BATSE error box
  40. GRB 000307, Optical Observations
  41. GRB 000307, BVRI Field Photometry
  42. GRB 000301C: A Precise Redshift Determination
  43. GRB 000301C, Optical Observation
  44. GRB 000301C: HST/STIS CCD Imaging of the field
  45. IPN error box for GRB000307
  46. GRB000301C, optical R-band observations
  47. GRB 000301C Optical Observations
  48. GRB 000301C: K' Observations
  49. GRB000301C OT candidate optical observations
  50. GRB000301C - Host galaxy not detected in R (?)
  51. Optical observations of GRB000301c
  52. GRB000301C, Radio observations
  53. GRB000301C, Radio observations
  54. GRB000301C, near-infrared observations (JHK' imaging)
  55. GRB 000301c near-IR observations
  56. GRB 000301C, UBVRI field photometry
  57. GRB 000301C: OT confirmed
  58. GRB000301c optical observations
  59. GRB000301C, optical observations
  60. GRB000301C
  61. GRB 000301C : Optical Candidate
  62. GRB000301C: RXTE/ASM and IPN localizations
  63. GRB000226 [IPN Position]
  64. HST Observations of GRB 990712
  65. GRB 000214 near-IR observations
  66. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  67. GRB000210, Radio Observations
  68. GRB 000115, BVRI field photometry
  69. GRB000214: BeppoSAX GRBM and WFC Detection
  70. Optical observations of GRB000210
  71. GRB000210 X-ray afterglow
  72. GRB000214: X-ray afterglow candidate
  73. GRB000214 refined BeppoSAX-WFC position
  74. GRB 000210: BATSE Observations
  75. Optical observations of the Chandra X-ray source for GRB000210
  76. GRB000210, Radio Observations
  77. IPN triangulation of GRB000210
  78. GRB000210: possible afterglow detection with BeppoSAX NFI
  79. GRB000201, Radio Observations
  80. GRB000210: BeppoSAX GRBM and WFC Detection
  81. SAX_WFC_GRB_NOTICE
  82. SAX_WFC_GRB_NOTICE
  83. GRB000201 Optical Observations
  84. GRB 000201: TAROT optical observations
  85. GRB 991208, radio observations
  86. BATSE+IPN location of GRB000131
  87. IPN localization of GRB000131
  88. GRB 000126, optical observations
  89. BATSE Observations of GRB000115
  90. Second RXTE Observation of GRB 000115
  91. GRB991216, UBVRIJHK field photometry
  92. GCN resumes full operations
  93. GRB 991216 VLBA Observations
  94. GRB 991216: J band spectrophotometry
  95. GRB 991216: Detection of the Host and/or Absorber Galaxy
  96. IPN localization of GRB991226
  97. GRB 991216 RXTE ASM Observations
  98. GRB 991216: Updated BATSE parameters
  99. GRB 991217 (SAX J2303.2+0015) Optical observations
  100. Chandra observation of the X-ray afterglow of GRB991216

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