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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"

35987 results found.

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

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