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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"

34205 results found.

  1. GRB 050820: Early RAPTOR detections
  2. GRB 050820 Swift-BAT refined analysis
  3. GRB 050820: P60 Temporal Decay Index
  4. GRB 050820: High Resolution Spectroscopy from Keck
  5. GRB050819: RTT150 optical observations
  6. GRB 050820: Swift detection of a GRB
  7. GRB 050819 Swift-BAT refined analysis
  8. GRB050819: Swift XRT position
  9. GRB050819: Swift-BAT detection of a weak burst
  10. Swift-BAT trigger 150993 is not a GRB
  11. Swift Trigger 150823 is HETE J1900.1-2455
  12. GRB 050817: Optical observations
  13. GRB 050815: Radio Observation
  14. GRB050814: Radio Observation
  15. GRB050817: Negative Optical Observations
  16. GRB 050814: continued fading
  17. GRB 050813: Radio Observations
  18. GRB050815: Refined analysis of the Swift-BAT burst
  19. GRB 050815: ROTSE-III Optical Limits
  20. GRB050815: Swift XRT afterglow localization
  21. GRB 050730: Third Epoch WSRT Radio Observations
  22. GRB050814: Fading red source
  23. GRB 050813: Gemini Spectra Revisited
  24. GRB 050813: Non-fading of afterglow candidate
  25. GRB 050814: XRT refined analysis
  26. GRB050814: Refined analysis of the Swift-BAT burst
  27. GRB050813: Gemini Imaging
  28. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  29. GRB 050814: Swift XRT Afterglow Localization
  30. GRB 050814: Swift detection of a burst
  31. GRB 050813: Magellan detection of a high redshift galaxy cluster
  32. GRB050813: RTT150 optical observations
  33. GRB 050813: I-band observations
  34. GRB050813, SDSS pre-burst observations
  35. GRB 050813: KAIT optical limit
  36. GRB 050813: Swift-BAT refined analysis
  37. GRB 050813: Photometry of object in XRT error circle
  38. GRB 050813: Swift XRT afterglow localization
  39. RBO GRB 050714A and GRB 050716 observations
  40. GRB 050813: Possible Short Swift-BAT GRB
  41. Swift-BAT trigger 150131 is not a GRB
  42. GRB050807(=H3889): An X-Ray Rich GRB Localized by HETE
  43. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  44. GRB050803: CrAO optical observations, no OT candidate
  45. GRB 050730: WSRT Radio Observations
  46. GRB 050803: PROMPT BVRcIc Observations
  47. GRB 050807: ROTSE-III Optical Limits
  48. GRB 050730, optical observation
  49. GRB050805b: CrAO optical limit
  50. GRB050805a : Null detection report
  51. GRB050730, optical observations
  52. GRB050803, optical observations
  53. Swift-BAT trigger 149118 is very likely not a GRB
  54. Retraction of Swift Trigger 149131 (GRB 050805B)
  55. GRB 050805b: OHP optical limits
  56. GRB 050805b: TAROT optical limits
  57. GRB050805b: MASTER optical observations
  58. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  59. GRB050805a: MASTER optical candidat
  60. Swift-BAT trigger 149118 is probably not a GRB
  61. GRB 050803: RTT150 optical observations
  62. GRB050803: CrAO optical observations, possible OT candidate
  63. GRB 050803: Keck Observations
  64. GRB 050803: Swift-BAT refined analysis
  65. GRB 050802.422: Fading of the afterglow and detection of the host
  66. GRB050803: MASTER further analys
  67. GRB 050803, optical observations
  68. GRB 050803: Magellan Observations
  69. GRB 050803: early Swift XRT analysis results
  70. GRB 050803: TAROT optical limits
  71. GRB050803: MASTER optical observations
  72. GRB050802: Tentative absorption redshift
  73. GCN GRB observation 050713A
  74. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  75. GRB 050802: Swift/UVOT optical and UV detections
  76. GRB050802: CrAO optical observations
  77. GRB050801: Unchanged decay slope
  78. GRB 050730: OHP optical observations
  79. GRB 050802: early Swift XRT analysis results
  80. GRB 050802: Swift/UVOT observations
  81. GRB 050802 : Lulin Optical follow-up observation
  82. GRB 050802: Swift-BAT refined analysis
  83. GRB050801: Optical photometry and decay index
  84. GRB 050802: XRT position
  85. GRB 050802: Swift Gamma-ray Burst
  86. GRB 050730: Preliminary Analysis of MIKE Spectrum
  87. GCN 050801: early Swift XRT analysis results
  88. GRB 050801: Swift-BAT refined analysis
  89. GRB 050801, SMARTS optical/IR afterglow observations
  90. GRB 050801, afterglow observations
  91. GRB 050730, corrected photometry and break?
  92. GRB 050801: ROTSE-III Early Afterglow Break
  93. GRB050801: Swift-BAT detection of a burst
  94. GRB 050801: ROTSE-III Detection of Possible Counterpart
  95. GRB 050730: XRT refined analysis
  96. Correction to GCN Circ 3476 on GRB050525A
  97. GRB 050730: early TAROT optical observations
  98. GRB 050726: PROMPT Rc Observations
  99. GRB 050730: RTT150 optical observations
  100. GRB 050730, spectra and optical photometry

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