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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"

3999 results found.

  1. GRB051028 SARA Observation
  2. SGR 1806-20: continued moderate activity seen with INTEGRAL
  3. GRB051021.63
  4. GRB 051016b: Optical limit
  5. GRB 051016B: Swift detection of a soft burst
  6. GRB050805A: Rc optical observations
  7. GRB/SGR 050925: IR Observations
  8. GRB050925: Swift-BAT detection of a short burst
  9. GRB 050915: Swift XRT refined analysis
  10. GRB 050915: ROTSE-III optical limits
  11. GRB050911: Upper limit on X-ray afterglow
  12. GRB 050906: Swift-BAT refined analysis
  13. GRB 050906: Bright galaxy in BAT error box
  14. GRB 050824: ROTSE-III Optical Limits
  15. GRB 050822: Swift detection of a long burst
  16. GRB050820: refined XRT analysis
  17. GRB 050820: P60 Temporal Decay Index
  18. GRB 050820: Swift detection of a GRB
  19. GRB050820: Optical afterglow from P60
  20. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  21. Detection of an intermediate burst from SGR 1806-20 on August 8
  22. GRB050805a: MASTER optical candidat
  23. GCN 050801: early Swift XRT analysis results
  24. GRB 050730, corrected photometry and break?
  25. GRB050801: Swift-BAT detection of a burst
  26. GRB 050730: early TAROT optical observations
  27. GRB 050730, spectra and optical photometry
  28. GRB 050724: Secure Host Redshift from Keck
  29. GRB050713: analysis of the XMM-Newton observation
  30. GRB 050721A: Swift-BAT refined analysis
  31. GRB050721A: Swift-BAT detection of a weak burst
  32. GRB050716: Refined analysis of the Swift-BAT burst
  33. Konus-Wind observation of GRB 050713A
  34. GRB 050713A: RAPTOR detection of early optical emission
  35. Swift-BAT Trigger 145729 is not a GRB
  36. GRB 050713A: Swift/UVOT observation
  37. RBO RI observations of GRB 050713A
  38. GRB050713: Liverpool Telescope prompt observations
  39. GRB050713: possible I-band afterglow
  40. GRB 050713: Swift detection of Bright Burst
  41. GRB 050713A: ROTSE-III Optical Limits
  42. GRB050709: A Possible Short-Hard GRB Localized by HETE
  43. GRB 050626: Swift XRT observations
  44. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  45. Konus-Wind observation of an intermediate burst from SGR 1806-20
  46. GRB 050525a, Mid-Infrared Observations
  47. GRB050607: P60 Observations
  48. Konus-Wind observation of GRB 050603
  49. GRB 050603: Swift XRT Position
  50. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  51. GRB 050603: INTEGRAL shows it is not a short GRB
  52. Swift/BAT Detection of GRB050603
  53. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  54. GRB 050525a: SARA Observations
  55. XRF 050522: Swift XRT observation
  56. RBO Observations of GRB050520
  57. GRB 050509b: No Optical Variability in XRT Error Circle
  58. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  59. GRB050509c (=H3751): An X-Ray Flash Localized By HETE
  60. Swift Detection of GRB050509b: A short duration burst
  61. GRB 050502a: Optical Observations
  62. Renewal of SGR 1806-20 activity
  63. GRB 050502A: WSRT Radio Observations
  64. GRB050502A: Optical Observations
  65. GRB 050502: Confirmed variability of the afterglow candidate +
  66. GRB050502 - Correction on the Optical Candidate from the Liverpool
  67. GRB 050502: ROTSE-III Detection of Possible Counterpart
  68. Swift-BAT Trigger 115881 is not a real GRB
  69. Swift/BAT possible detection of a weak burst GRB050430
  70. GRB 050421: IR Observations
  71. Swift Detection of GRB050421
  72. GRB050408: optical observation
  73. GRB050408: Radio Observations
  74. GRB 050408,optical observation
  75. GRB 050408, optical observations
  76. GRB 050319 : Confirmation of optical afterglow decay
  77. GRB050318: Swift XRT position
  78. GRB050309: CONCAM pre-trigger and trigger coincident optical
  79. GRB 050306: further TAROT optical data
  80. Ongoing activity of SGR 1806-20 after the giant flare
  81. GRB050215A: ROTSE-III Optical Observations
  82. GRB 050129: a weak long GRB detected with INTEGRAL
  83. SGR 1806-20: GMRT results at 240 MHz band.
  84. SGR 1806-20: low frequency GMRT results of 2005 Jan 16.
  85. GRB050117: Refined XRT position
  86. SGR 1806-20: RXTE/PCA pulse frequency during flare
  87. SGR 1806-20: Further VLA Observations
  88. SGR 1806-20: Further low frequency GMRT results
  89. SGR 1806-20: Further VLA Observations
  90. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  91. Further VLA observations of SGR 1806-20
  92. SGR 1806-20 and extragalactic short-duration GRBs
  93. Further ATCA observations of SGR 1806-20
  94. Fourth Epoch VLA observations of SGR 1806-20
  95. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  96. SGR 1806-20: Temporal and Spectral behavior of radio transient
  97. ATCA observations of SGR 1806-20
  98. SGR 1806-20, RHESSI observations of the 041227 giant flare
  99. Third epoch observations of SGR 1806-20 with VLA
  100. Second Epoch VLA observations of SGR 1806-20

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