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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"

20557 results found.

  1. GRB 051103, optical observations
  2. GRB051103: MASTER: OT limit and host galaxy candidates
  3. GRB051028: Swift-XRT refined analysis
  4. GRB 051105A, 2nd epoch optical observations
  5. GRB 051105a: MDM Observations
  6. GRB 051105A: TNG optical observations
  7. GRB051105A: Swift/UVOT Observations
  8. GRB 051105A, radio observations
  9. GRB 051105A, optical observations
  10. XRT observations of GRB 051105A
  11. GRB 051016B host spectroscopy and redshift
  12. GRB051028:MASTER correction and final results
  13. GRB 051022: RTT150 optical observations
  14. GRB 051021A: RTT150 optical observations
  15. GRB051028 SARA Observation
  16. GRB051028: optical observations
  17. GRB051028: WHT optical candidate
  18. GRB051028:MASTER observations
  19. GRB051028:MASTER optical observations
  20. GRB 051022: XRT Refined Spectral and Temporal Analysis--Correction
  21. GRB051022: Swift XRT measurement of jet break
  22. GRB 051021, Optical Observations
  23. GRB 051022: XRT Refined Spectral and Temporal Analysis
  24. GRB 051022, refined optical astrometry
  25. Chandra Observations of GRB 051022
  26. GRB051012: Swift-XRT analysis
  27. GRB 051022 Chandra Observations scheduled
  28. GRB051021B: Swift XRT refined analysis
  29. GRB051021a: optical observations
  30. GRB 051022: WSRT Radio Detection
  31. GRB 051022, mm counterpart
  32. GRB051022: host galaxy redshift
  33. GRB051022: Radio Counterpart
  34. GRB051022: IR observations
  35. GRB 051022: SOAR JKs Observations
  36. GRB051022: Optical Observations
  37. GRB 051021: PROMPT RcIc Observations
  38. GRB 051022, J & K-band observation
  39. GRB 051021, SMARTS optical/IR observations
  40. GRB 051021: P200 Ks Observations
  41. GRB 051022: SSO40 Optical Observations
  42. GRB051022 (=H3590), A GRB Detected By HETE
  43. GRB 051022: Optical observations
  44. GRB 051021: SOAR NIR Observations
  45. GRB051021: Swift XRT analysis
  46. GRB 051021 : optical afterglow observation at Lulin
  47. GRB 051021: Optical observations
  48. GRB 051021: ROTSE-III Confirmation of Optical Counterpart
  49. GRB 051021: Optical observations and candidate afterglow
  50. GRB 051016b: Gemini Near IR Observations
  51. GRB 051016: PROMPT Observations
  52. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  53. GRB051006: optical observations
  54. GRB050805A: Rc optical observations
  55. GRB051008: optical candidate
  56. GRB051008: optical observation
  57. GRB051008: Swift XRT refined analysis
  58. GRB 051008, optical observations
  59. GRB 051006: P60 Observations
  60. GRB 051006: optical observations at Sierra Nevada
  61. GRB 050906, summary of radio observations
  62. GRB 050925: Second Epoch WSRT Radio Observations
  63. GRB 051001: Swift XRT refined analysis
  64. GRB 051001, optical observations at Mt. John
  65. GRB 051001: AAT infra-red observations
  66. GRB 051001: ROTSE-III Optical Limits
  67. GRB050908: optical observations
  68. GRB 050922C: further VLT observations
  69. GRB050922C: UVES/VLT high resolution spectroscopy
  70. GRB/SGR 050925: IR Observations
  71. GRB 050922C: break in the lightcurve
  72. GRB 050925: WSRT Radio Observations
  73. GRB050925: Swift UVOT upper limits
  74. GRB 050925 : I-band observation at Xinglong observatory
  75. GRB050922C: TNG spectroscopic observations
  76. GRB050922C: Optical Observations
  77. GRB 050922C: Swift XRT refined analysis
  78. HETE Fregate observations of GRB 050922C
  79. GRB050922C: optical observations
  80. GRB 050922C: NOT optical observations
  81. GRB 050922C: ROTSE-IIId Refined Analysis
  82. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  83. GRB050918: Possible Swift/XRT detected afterglow
  84. GRB 050915a: Radio Observations
  85. Swift-BAT trigger 155764 is not a GRB
  86. GRB 050915b, SMARTS optical/IR observations of the XRT position
  87. GRB 050915b, SMARTS optical/IR observations
  88. GRB 050915: IR Observations
  89. GRB050915: P60 Optical Observations
  90. GRB050915, optical observations
  91. Swift-BAT trigger 155072 ground analysis
  92. GRB 050911: LCO limits on a variable source
  93. GRB050911: Swift UVOT followup observations
  94. GRB 050911, optical content of Swift/XRT error box
  95. GRB 050911: LCO observations
  96. GRB 050911, optical observations
  97. GRB 050911: z~0.16 cluster in the field
  98. GRB 050910a: TAROT early optical limits
  99. RBO GRB 050908 observations
  100. WIRO observations in I of GRB 050908

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