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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"

8474 results found.

  1. GRB 050315, SMARTS optical/IR afterglow observations
  2. GRB 050315: Absorption redshift
  3. Swift-BAT detection of GRB 050315
  4. GRB 050306: Radio Observations
  5. GRB 050306: Confirmation of X-ray afterglow
  6. GRB 050309, Early optical limits from RAPTOR
  7. GRB 050306: CORRECTION to date of observation
  8. GRB 050306: R-band observations
  9. GRB 050306: No Swift UVOT Optical Counterpart Detected
  10. GRB 050306: REM optical-infrared observations
  11. GRB 050306: Possible X-ray Afterglow Position from the Swift
  12. Ongoing activity of SGR 1806-20 after the giant flare
  13. GRB 050126: Confirmation of the NIR afterglow candidate
  14. GRB 050219b: candidate NIR afterglow
  15. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  16. GRB 050215B: Radio Observations
  17. GRB 050215b: XRT confirmation of IR afterglow candidate
  18. GRB050215b: P60 Optical Observations
  19. GRB 050215b: Swift XRT Source Variability
  20. GRB 050215B: candidate afterglow
  21. GRB 050124: Radio Observations
  22. GRB 050126: A NIR afterglow candidate in the revised XRT error circle
  23. GRB 050126: Radio Observations
  24. GRB 050128: Swift XRT prompt afterglow position
  25. GRB 050124: NIR Candidates from Keck/NIRC
  26. GRB 050123 : I-band follow-up observation
  27. Unusual optical transient (GRB ???)
  28. Detection of the SGR 1806-20 giant outburst back-scattered by the
  29. GRB041223: decay of the afterglow
  30. GRB041223: optical and NIR observations with REM
  31. Very high activity of SGR 1806-20
  32. GRB 041219: Keck IR Observations and Astrometric Refinement of the
  33. GRB 041219 : optical follow-up observations
  34. Deep RAPTOR observations during GRB 041219
  35. GRB041218: Continued P60 Optical Observations
  36. GRB 041219: Infrared Afterglow Candidate
  37. GRB 041219: Infrared Afterglow Candidate
  38. GRB 041217: PROMPT Observations
  39. GRB041218: optical observations
  40. GRB 041218; optical candidate
  41. GRB 041218: Optical observations
  42. GRB041211, Faulkes Telescope optical observation
  43. Summary of the recent bursts from SGR 1806-20
  44. Bright bursts from SGR1806-20
  45. GRB041006: Fading X-ray Afterglow Observed with Chandra
  46. GRB 040924: VLT spectroscopy
  47. GRB 041006 : Optical follow-up observation at TAROT
  48. GRB041006: Fading of optical afterglow candidate
  49. GRB 041006 : Optical follow-up observation at KISO
  50. GRB 041006: Finding chart
  51. GRB 041006: Optical afterglow candidate
  52. radio observations, GRB 040924
  53. GRB040924,optical observation
  54. GRB 040924: detection of possible host galaxy by Subaru
  55. GRB040924, RTT150 optical observation
  56. GRB040924: Afterglow magnitude at t=17.5hr
  57. GRB040924 : Optical candidate observations at Lulin observatory
  58. GRB040924 : Optical candidate observations at Lulin observatory
  59. GRB 040924: Subaru NIR observation
  60. GRB040924: Optical afterglow properties
  61. IPN triangulation of GRB040924 (H3564)
  62. GRB040924 (H3564): Optical afterglow candidate
  63. XRF 040912: Radio Observations
  64. XRF 040916: Radio Observations
  65. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  66. XRF040916: continuing decay of OT
  67. TAROT Observations of GRB 040916 (HETE #3558)
  68. GRB040912(=H3557): Candidate Optical Afterglow
  69. XRF040916, optical observations
  70. XRF040916: Optical Transient Candidate by Subaru
  71. XRF040916, Ic observations
  72. XRF040916: optical follow-up observations
  73. GRB040916: Archival optical observations
  74. GRB040916: Optical observations
  75. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  76. GRB 040912, BVRI observations
  77. An intense burst from SGR1806-20
  78. HETE 3557: Optical observations
  79. GRB 040827 - Radio Observations
  80. GRB040825A: Optical observations
  81. GRB040825A: Optical observations
  82. Increase of SGR 1806-20 activity
  83. GRB 040825: Optical observations
  84. XRF040812: possible afterglow second Chandra observation
  85. GRB 040812: Second epoch CXO Observations
  86. XRF040701: Optical Observations at ESO
  87. Ongoing activity of SGR 1806-20
  88. XRF 040701 - optical observations of the decaying Chandra source
  89. XRF040701: Second-Epoch Chandra Observations
  90. XRF040701: VLA Observations
  91. XRF 040701, optical observations
  92. Activivty of SGR 1806-20
  93. GRB 040511, very fast decay?
  94. GRB 030324: Detection and Color of Host Galaxy
  95. GRB040511: Redshift identifcation
  96. GRB 040511: Optical limit
  97. GRB040511: Candidate optical/NIR afterglow
  98. GRB 040403: Optical Observations
  99. GRB040323: NIR Observations and Variable Object
  100. GRB 031203: spectoscopic evidence for a 1998bw-like SN

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