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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"

8476 results found.

  1. GRB 050803: RTT150 optical observations
  2. GRB050803: CrAO optical observations, possible OT candidate
  3. GRB 050803, optical observations
  4. GRB 050802: Swift/UVOT optical and UV detections
  5. GRB050801: Optical photometry and decay index
  6. GRB 050730, SMARTS optical/IR afterglow observations
  7. GRB050730: Liverpool Telescope optical observations
  8. GRB 050730, optical candidate
  9. GRB 050724: Optical imaging/astrometry
  10. GRB 050721A: Swift-BAT refined analysis
  11. GRB 050721a: Optical Observations
  12. GRB 050714a: Refined XRT analysis and afterglow confirmation
  13. GRB 050716; J-band observations
  14. GRB 050716 - UKIRT identification of candidate afterglow
  15. GRB 050716: Refined XRT analysis.
  16. GRB050716: Faulkes North Telescope observation
  17. GRB 050714B: refined XRT analysis
  18. GRB 050714B: candidate afterglow does not fade
  19. GRB 050709: optical afterglow candidate
  20. GRB 050714, R-band candidate
  21. GRB 050709: Spectroscopy
  22. GRB 050713B: Swift-BAT Refined Analysis
  23. GRB050713B: Faulkes North Telescope observation
  24. RBO RI observations of GRB 050713A
  25. GRB050709: Candidate X-ray Afterglow from Chandra
  26. GRB 050713: ARC NIR Detections and Identification of Fading
  27. GRB050712: UVOT candidate optical counterpart
  28. GRB 050626: Swift XRT observations
  29. H3804: A Possible New XRB Detected by HETE
  30. Konus-Wind observation of an intermediate burst from SGR 1806-20
  31. GRB 050607: MDM Observations
  32. Limits on a SN in the field of GRB 050509b
  33. GRB 050603: Swift XRT Position
  34. GRB050528, XRT observations
  35. GRB050528: BOOTES optical candidate (retraction)
  36. GRB050528: BOOTES optical candidate
  37. Possible GRB050528: no candidate from Liverpool Telescope
  38. GRB050525: Super-LOTIS observations
  39. GRB 050525a: Gemini/GMOS Spectra
  40. GRB050306: optical afterglow not confirmed
  41. GRB050525: Optical observations
  42. GRB 050525: Optical observation
  43. XRF050522: NIR observations of XRT candidate
  44. XRF 050522: Swift XRT refined analysis
  45. XRF050522: Optical Observations
  46. GRB 050520: Swift XRT refined analysis
  47. XRF 050509c: Swift XRT Upper Limit
  48. GRB050520: Liverpool Telescope follow-up
  49. XRF 050509C: REM NIR and Optical refined analysis
  50. GRB 050504: Swift XRT afterglow candidate has faded
  51. XRF 050509c optical afterglow
  52. Chandra observation of GRB 050509b
  53. GRB 050509b: RAPTOR deep, early limits.
  54. GRB 050509b: Further Analysis of Keck LRIS Images
  55. GRB 050509b: Physical Properties of the Candidate Host galaxy
  56. GRB 050509B, Optical Observations
  57. GRB 050509B: Swift/XRT refined analysis
  58. GRB 050509b: Optical observations
  59. GRB 050509b: Optical Counterpart Candidate
  60. GRB 050505 - Faulkes Telescope North observations
  61. GRB 050502a: Swift XRT Upper Limit
  62. GRB050505: Infrared observations
  63. GRB050505: AAVSO observations
  64. GRB 050505: Keck absorption spectrum and redshift (z=4.27)
  65. GRB050505: Optical Afterglow Candidate
  66. GRB 050416b:Swift XRT afterglow upper limits
  67. GRB 050416b:Swift XRT afterglow upper limits
  68. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  69. GRB050502b: Afterglow Confirmation
  70. Renewal of SGR 1806-20 activity
  71. GRB050502A: Optical Observations
  72. Swift UVOT refined analysis
  73. GRB 050502: Confirmed variability of the afterglow candidate +
  74. GRB050502 - Correction on the Optical Candidate from the Liverpool
  75. GRB050502 - Optical Candidate from the Liverpool Telescope
  76. Swift Detection of GRB 050422
  77. GRB 050421: NIR observations
  78. GRB 050416b: Tentative Swift XRT Position
  79. GRB 050416b: Swift-BAT refined analysis
  80. GRB050416: P200 NIR Observations
  81. GRB 050416: Swift XRT Position
  82. GRB 050416: Radio observations
  83. GRB050416: P60 Afterglow Candidate
  84. GRB 050412 : XingLong optical observation
  85. GRB 050408: Subaru Observations
  86. GRB 050408 Optical Observations
  87. GRB 050408: Magellan astrometry and photometry
  88. GRB 050408: First Optical observations with TFOSC at the RTT150
  89. GRB 050408 optical candidate
  90. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  91. GRB 050401 Optical Observations
  92. GRB050402: XDSS counterpart
  93. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  94. GRB 050401: Optical afterglow confirmed
  95. GRB 050401: Optical afterglow candidate
  96. GRB 050319 R band observations
  97. GRB 050319: NIR afterglow candidate
  98. GRB 050319:Near IR afterglow
  99. GRB050319: BR optical photometry
  100. GRB 050319 : Confirmation of optical afterglow decay

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