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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 050803, optical observations
  2. GRB 050802: Swift/UVOT optical and UV detections
  3. GRB050801: Optical photometry and decay index
  4. GRB 050730, SMARTS optical/IR afterglow observations
  5. GRB050730: Liverpool Telescope optical observations
  6. GRB 050730, optical candidate
  7. GRB 050724: Optical imaging/astrometry
  8. GRB 050721A: Swift-BAT refined analysis
  9. GRB 050721a: Optical Observations
  10. GRB 050714a: Refined XRT analysis and afterglow confirmation
  11. GRB 050716; J-band observations
  12. GRB 050716 - UKIRT identification of candidate afterglow
  13. GRB 050716: Refined XRT analysis.
  14. GRB050716: Faulkes North Telescope observation
  15. GRB 050714B: refined XRT analysis
  16. GRB 050714B: candidate afterglow does not fade
  17. GRB 050709: optical afterglow candidate
  18. GRB 050714, R-band candidate
  19. GRB 050709: Spectroscopy
  20. GRB 050713B: Swift-BAT Refined Analysis
  21. GRB050713B: Faulkes North Telescope observation
  22. RBO RI observations of GRB 050713A
  23. GRB050709: Candidate X-ray Afterglow from Chandra
  24. GRB 050713: ARC NIR Detections and Identification of Fading
  25. GRB050712: UVOT candidate optical counterpart
  26. GRB 050626: Swift XRT observations
  27. H3804: A Possible New XRB Detected by HETE
  28. Konus-Wind observation of an intermediate burst from SGR 1806-20
  29. GRB 050607: MDM Observations
  30. Limits on a SN in the field of GRB 050509b
  31. GRB 050603: Swift XRT Position
  32. GRB050528, XRT observations
  33. GRB050528: BOOTES optical candidate (retraction)
  34. GRB050528: BOOTES optical candidate
  35. Possible GRB050528: no candidate from Liverpool Telescope
  36. GRB050525: Super-LOTIS observations
  37. GRB 050525a: Gemini/GMOS Spectra
  38. GRB050306: optical afterglow not confirmed
  39. GRB050525: Optical observations
  40. GRB 050525: Optical observation
  41. XRF050522: NIR observations of XRT candidate
  42. XRF 050522: Swift XRT refined analysis
  43. XRF050522: Optical Observations
  44. GRB 050520: Swift XRT refined analysis
  45. XRF 050509c: Swift XRT Upper Limit
  46. GRB050520: Liverpool Telescope follow-up
  47. XRF 050509C: REM NIR and Optical refined analysis
  48. GRB 050504: Swift XRT afterglow candidate has faded
  49. XRF 050509c optical afterglow
  50. Chandra observation of GRB 050509b
  51. GRB 050509b: RAPTOR deep, early limits.
  52. GRB 050509b: Further Analysis of Keck LRIS Images
  53. GRB 050509b: Physical Properties of the Candidate Host galaxy
  54. GRB 050509B, Optical Observations
  55. GRB 050509B: Swift/XRT refined analysis
  56. GRB 050509b: Optical observations
  57. GRB 050509b: Optical Counterpart Candidate
  58. GRB 050505 - Faulkes Telescope North observations
  59. GRB 050502a: Swift XRT Upper Limit
  60. GRB050505: Infrared observations
  61. GRB050505: AAVSO observations
  62. GRB 050505: Keck absorption spectrum and redshift (z=4.27)
  63. GRB050505: Optical Afterglow Candidate
  64. GRB 050416b:Swift XRT afterglow upper limits
  65. GRB 050416b:Swift XRT afterglow upper limits
  66. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  67. GRB050502b: Afterglow Confirmation
  68. Renewal of SGR 1806-20 activity
  69. GRB050502A: Optical Observations
  70. Swift UVOT refined analysis
  71. GRB 050502: Confirmed variability of the afterglow candidate +
  72. GRB050502 - Correction on the Optical Candidate from the Liverpool
  73. GRB050502 - Optical Candidate from the Liverpool Telescope
  74. Swift Detection of GRB 050422
  75. GRB 050421: NIR observations
  76. GRB 050416b: Tentative Swift XRT Position
  77. GRB 050416b: Swift-BAT refined analysis
  78. GRB050416: P200 NIR Observations
  79. GRB 050416: Swift XRT Position
  80. GRB 050416: Radio observations
  81. GRB050416: P60 Afterglow Candidate
  82. GRB 050412 : XingLong optical observation
  83. GRB 050408: Subaru Observations
  84. GRB 050408 Optical Observations
  85. GRB 050408: Magellan astrometry and photometry
  86. GRB 050408: First Optical observations with TFOSC at the RTT150
  87. GRB 050408 optical candidate
  88. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  89. GRB 050401 Optical Observations
  90. GRB050402: XDSS counterpart
  91. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  92. GRB 050401: Optical afterglow confirmed
  93. GRB 050401: Optical afterglow candidate
  94. GRB 050319 R band observations
  95. GRB 050319: NIR afterglow candidate
  96. GRB 050319:Near IR afterglow
  97. GRB050319: BR optical photometry
  98. GRB 050319 : Confirmation of optical afterglow decay
  99. GRB 050315, SMARTS optical afterglow decay
  100. GRB050316: MASTER optical observations

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