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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"

28041 results found.

  1. GRB 000418, Optical Observation
  2. GRB000418, near-infrared observations
  3. Correction to IPN error box for GRB000419
  4. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  5. GRB000416 BRJK observations
  6. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  7. GRB 000408, optical observations
  8. GRB 991208, UBVRI field photometry
  9. GRB000408, lotis optical observations
  10. GRB 000301C: Late-Time HST/STIS CCD Imaging of the field
  11. GRB000301C - Addendum to GCN 623
  12. GRB 000323, optical observations
  13. GRB 000326: Optical Observations
  14. GRB000326, Radio observations
  15. GRB000313, Radio observations
  16. GRB 000313 - optical transient in the BATSE error box
  17. GRB 000307, Optical Observations
  18. GRB 000307, BVRI Field Photometry
  19. GRB 000301C: A Precise Redshift Determination
  20. GRB 000301C, Optical Observation
  21. GRB 000301C: HST/STIS CCD Imaging of the field
  22. IPN error box for GRB000307
  23. GRB000301C, optical R-band observations
  24. GRB 000301C Optical Observations
  25. GRB 000301C: K' Observations
  26. GRB000301C OT candidate optical observations
  27. GRB000301C - Host galaxy not detected in R (?)
  28. Optical observations of GRB000301c
  29. GRB000301C, Radio observations
  30. GRB000301C, Radio observations
  31. GRB000301C, near-infrared observations (JHK' imaging)
  32. GRB 000301c near-IR observations
  33. GRB 000301C, UBVRI field photometry
  34. GRB 000301C: OT confirmed
  35. GRB000301c optical observations
  36. GRB000301C, optical observations
  37. GRB000301C
  38. GRB 000301C : Optical Candidate
  39. GRB000301C: RXTE/ASM and IPN localizations
  40. GRB000226 [IPN Position]
  41. HST Observations of GRB 990712
  42. GRB 000214 near-IR observations
  43. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  44. GRB000210, Radio Observations
  45. GRB 000115, BVRI field photometry
  46. GRB000214: BeppoSAX GRBM and WFC Detection
  47. Optical observations of GRB000210
  48. GRB000210 X-ray afterglow
  49. GRB000214: X-ray afterglow candidate
  50. GRB000214 refined BeppoSAX-WFC position
  51. GRB 000210: BATSE Observations
  52. Optical observations of the Chandra X-ray source for GRB000210
  53. GRB000210, Radio Observations
  54. IPN triangulation of GRB000210
  55. GRB000210: possible afterglow detection with BeppoSAX NFI
  56. GRB000201, Radio Observations
  57. GRB000210: BeppoSAX GRBM and WFC Detection
  58. SAX_WFC_GRB_NOTICE
  59. SAX_WFC_GRB_NOTICE
  60. GRB000201 Optical Observations
  61. GRB 000201: TAROT optical observations
  62. GRB 991208, radio observations
  63. BATSE+IPN location of GRB000131
  64. IPN localization of GRB000131
  65. GRB 000126, optical observations
  66. BATSE Observations of GRB000115
  67. Second RXTE Observation of GRB 000115
  68. GRB991216, UBVRIJHK field photometry
  69. GCN resumes full operations
  70. GRB 991216 VLBA Observations
  71. GRB 991216: J band spectrophotometry
  72. GRB 991216: Detection of the Host and/or Absorber Galaxy
  73. IPN localization of GRB991226
  74. GRB 991216 RXTE ASM Observations
  75. GRB 991216: Updated BATSE parameters
  76. GRB 991217 (SAX J2303.2+0015) Optical observations
  77. Chandra observation of the X-ray afterglow of GRB991216
  78. GRB 991216, optical observations
  79. GRB 991216 Optical spectroscopy/imaging
  80. SAX J2303.2+0015 Optical observations
  81. IR observations of GRB991216
  82. GRB 991217 (SAX J2303.2+0015) Optical observations
  83. GRB991216 Optical and infrared observations of Beethoven Burst
  84. GRB 991216 Radio Observations
  85. GRB 991208 Keck Spectroscopy
  86. GRB 991208 Infrared Detection
  87. GRB991216
  88. GRB 991216--Summary of RXTE Observations
  89. GRB 991216 Optical Observations
  90. GRB 991216, optical observations
  91. GRB 991208 SAO-RAS Spectroscopy
  92. SAX J2303.2+0015: an x-ray/GRB?
  93. GRB 991216, Optical Transient
  94. GRB991216 ('Beethoven Burst') B, R, and K Observations
  95. GRB991216, infrared observations
  96. GRB 991208 optical observations
  97. GRB 991216 Optical Observation
  98. GRB 991216: Extremely bright BATSE burst
  99. R-band Observations of GRB991208 at TNG
  100. GRB991208, optical observations

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