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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').
  1. GRB051109B: no UVOT source detected
  2. GRB051109B: XRT refined analysis
  3. GRB 051109B : Lulin Optical Observations
  4. GRB 051109A : Lulin BVRI Optical afterglow observation
  5. GRB051109A: further steepening in the X-ray light curve
  6. GRB051109A: XRT refined analysis
  7. GRB 051109a: BOOTES R & I-band detection of the early afterglow
  8. GRB051109B: XRT position
  9. GRB 051109B: Super-LOTIS Observations
  10. GRB 051109B Kiso optical follow-up observation
  11. GRB051105B: REM Optical observation
  12. GRB 051109B: Swift detection of a burst
  13. GRB 051109: HET Optical Spectrum and Absorption Redshift
  14. GRB 051109: PROMPT Detections
  15. GRB 051109: Rc and Ic observations
  16. GRB051109: Early Super-LOTIS Detection
  17. GRB 051109: Swift-BAT refined analysis
  18. GRB 051109a: IR Photometry and Astrometry
  19. GRB 051109a: MDM Observations
  20. GRB 051109A: ROTSE-III Decline rate for Optical Counterpart
  21. GRB051109: Swift detection of a burst
  22. GRB 051109a: IR Detections
  23. GRB 051109: ROTSE-III Detection of Possible Counterpart
  24. GRB051105B: Swift/XRT upper limit
  25. GRB051105B: Swift/UVOT upper limit
  26. GRB051103: optical observations
  27. GRB 051103, optical observations
  28. GRB051103: MASTER: OT limit and host galaxy candidates
  29. GRB051028: Swift-XRT refined analysis
  30. GRB 051105a, observation from Naini Tal and OSN
  31. GRB 051105A, 2nd epoch optical observations
  32. GRB 051105a: MDM Observations
  33. GRB 051105A: TNG optical observations
  34. GRB051105A: Swift/UVOT Observations
  35. GRB 051105A, radio observations
  36. GRB051103:_MASTER_optical_observations
  37. IPN triangulation and Konus spectrum of the bright short/hard GRB051103
  38. GRB 051105A, optical observations
  39. XRT observations of GRB 051105A
  40. GRB 051105: Swift-BAT improved refined analysis
  41. GRB 051105b: ART optical limits
  42. GRB051105B - A long GRB detected by INTEGRAL
  43. GRB 051105B (INTEGRAL 2701): Optical observation
  44. GRB 051105: Swift-BAT refined analysis
  45. GRB 051105: Optical limit
  46. GRB 051105: Swift detection of a short burst
  47. IBAS Alert 2700: Not a GRB
  48. GRB 051016B host spectroscopy and redshift
  49. GRB051016B: optical observation
  50. Recent GRB UBVRcIc field photometry
  51. Konus-Wind observation of GRB 051028
  52. GRB051028:MASTER correction and final results
  53. GRB 051022: RTT150 optical observations
  54. GRB 051021A: RTT150 optical observations
  55. GRB051028 SARA Observation
  56. GRB051028: optical observations
  57. GRB051028: Swift/UVOT upper limits
  58. GRB051028: confirmation of the afterglow
  59. GRB051028: WHT optical candidate
  60. GRB051028: Swift XRT Position
  61. GRB051028:MASTER observations
  62. GRB 051028 (=H3951): A GRB localized by HETE
  63. GRB051028:MASTER optical observations
  64. GRB 051022: XRT Refined Spectral and Temporal Analysis--Correction
  65. GRB051022: Swift XRT measurement of jet break
  66. SGR 1806-20: continued moderate activity seen with INTEGRAL
  67. GRB051021B: Swift/UVOT Upper limits
  68. GRB 051021, Optical Observations
  69. GRB 051022: XRT Refined Spectral and Temporal Analysis
  70. GRB 051022, refined optical astrometry
  71. Chandra Observations of GRB 051022
  72. GRB051012: Swift-XRT analysis
  73. GRB 051022 Chandra Observations scheduled
  74. GRB051021B: Swift XRT refined analysis
  75. GRB051021a: optical observations
  76. GRB 051022: WSRT Radio Detection
  77. GRB 051022, mm counterpart
  78. GRB051022: host galaxy redshift
  79. GRB 051022: Swift/UVOT Upper Limits
  80. GRB051022: Radio Counterpart
  81. GRB051022: IR observations
  82. GRB 051022: SOAR JKs Observations
  83. GRB051021A: Swift XRT refined analysis
  84. Konus-Wind observation of GRB 051022
  85. GRB051022: Optical Observations
  86. GRB 051022: Magellan NIR imaging
  87. GRB 051021: PROMPT RcIc Observations
  88. GRB051021b: Magellan IR Imaging
  89. GRB 051022: Spectral Analysis Indicates That The Spectrum Is Absorbed
  90. GRB 051021: Correction
  91. GRB 051022, J & K-band observation
  92. GRB 051021, SMARTS optical/IR observations
  93. GRB051022: Swift XRT Position
  94. GRB 051021: P200 Ks Observations
  95. IPN triangulation of GRB051022 (=H3950)
  96. GRB 051021: MDM Upper Limit
  97. GRB 051022 (=H3950): SXC Flight Localization is Valid
  98. GRB051021: Swift/UVOT Upper Limits
  99. GRB 051021B: Refined analysis of the Swift-BAT burst
  100. GRB 051022: SSO40 Optical Observations

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