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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"

28050 results found.

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

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Download all Circulars as a .tar.gz archive (updated once a day):
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