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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"

8284 results found.

  1. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  2. GRB 050401: Optical afterglow confirmed
  3. GRB 050401: Optical afterglow candidate
  4. GRB 050319 R band observations
  5. GRB 050319: NIR afterglow candidate
  6. GRB 050319:Near IR afterglow
  7. GRB050319: BR optical photometry
  8. GRB 050319 : Confirmation of optical afterglow decay
  9. GRB 050315, SMARTS optical afterglow decay
  10. GRB050316: MASTER optical observations
  11. GRB 050315, SMARTS optical/IR afterglow observations
  12. GRB 050315: Absorption redshift
  13. Swift-BAT detection of GRB 050315
  14. GRB 050306: Radio Observations
  15. GRB 050306: Confirmation of X-ray afterglow
  16. GRB 050309, Early optical limits from RAPTOR
  17. GRB 050306: CORRECTION to date of observation
  18. GRB 050306: R-band observations
  19. GRB 050306: No Swift UVOT Optical Counterpart Detected
  20. GRB 050306: REM optical-infrared observations
  21. GRB 050306: Possible X-ray Afterglow Position from the Swift
  22. Ongoing activity of SGR 1806-20 after the giant flare
  23. GRB 050126: Confirmation of the NIR afterglow candidate
  24. GRB 050219b: candidate NIR afterglow
  25. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  26. GRB 050215B: Radio Observations
  27. GRB 050215b: XRT confirmation of IR afterglow candidate
  28. GRB050215b: P60 Optical Observations
  29. GRB 050215b: Swift XRT Source Variability
  30. GRB 050215B: candidate afterglow
  31. GRB 050124: Radio Observations
  32. GRB 050126: A NIR afterglow candidate in the revised XRT error circle
  33. GRB 050126: Radio Observations
  34. GRB 050128: Swift XRT prompt afterglow position
  35. GRB 050124: NIR Candidates from Keck/NIRC
  36. GRB 050123 : I-band follow-up observation
  37. Unusual optical transient (GRB ???)
  38. Detection of the SGR 1806-20 giant outburst back-scattered by the
  39. GRB041223: decay of the afterglow
  40. GRB041223: optical and NIR observations with REM
  41. Very high activity of SGR 1806-20
  42. GRB 041219: Keck IR Observations and Astrometric Refinement of the
  43. GRB 041219 : optical follow-up observations
  44. Deep RAPTOR observations during GRB 041219
  45. GRB041218: Continued P60 Optical Observations
  46. GRB 041219: Infrared Afterglow Candidate
  47. GRB 041219: Infrared Afterglow Candidate
  48. GRB 041217: PROMPT Observations
  49. GRB041218: optical observations
  50. GRB 041218; optical candidate
  51. GRB 041218: Optical observations
  52. GRB041211, Faulkes Telescope optical observation
  53. Summary of the recent bursts from SGR 1806-20
  54. Bright bursts from SGR1806-20
  55. GRB041006: Fading X-ray Afterglow Observed with Chandra
  56. GRB 040924: VLT spectroscopy
  57. GRB 041006 : Optical follow-up observation at TAROT
  58. GRB041006: Fading of optical afterglow candidate
  59. GRB 041006 : Optical follow-up observation at KISO
  60. GRB 041006: Finding chart
  61. GRB 041006: Optical afterglow candidate
  62. radio observations, GRB 040924
  63. GRB040924,optical observation
  64. GRB 040924: detection of possible host galaxy by Subaru
  65. GRB040924, RTT150 optical observation
  66. GRB040924: Afterglow magnitude at t=17.5hr
  67. GRB040924 : Optical candidate observations at Lulin observatory
  68. GRB040924 : Optical candidate observations at Lulin observatory
  69. GRB 040924: Subaru NIR observation
  70. GRB040924: Optical afterglow properties
  71. IPN triangulation of GRB040924 (H3564)
  72. GRB040924 (H3564): Optical afterglow candidate
  73. XRF 040912: Radio Observations
  74. XRF 040916: Radio Observations
  75. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  76. XRF040916: continuing decay of OT
  77. TAROT Observations of GRB 040916 (HETE #3558)
  78. GRB040912(=H3557): Candidate Optical Afterglow
  79. XRF040916, optical observations
  80. XRF040916: Optical Transient Candidate by Subaru
  81. XRF040916, Ic observations
  82. XRF040916: optical follow-up observations
  83. GRB040916: Archival optical observations
  84. GRB040916: Optical observations
  85. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  86. GRB 040912, BVRI observations
  87. An intense burst from SGR1806-20
  88. HETE 3557: Optical observations
  89. GRB 040827 - Radio Observations
  90. GRB040825A: Optical observations
  91. GRB040825A: Optical observations
  92. Increase of SGR 1806-20 activity
  93. GRB 040825: Optical observations
  94. XRF040812: possible afterglow second Chandra observation
  95. GRB 040812: Second epoch CXO Observations
  96. XRF040701: Optical Observations at ESO
  97. Ongoing activity of SGR 1806-20
  98. XRF 040701 - optical observations of the decaying Chandra source
  99. XRF040701: Second-Epoch Chandra Observations
  100. XRF040701: VLA Observations

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