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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"

35259 results found.

  1. GRB050813: RTT150 optical observations
  2. GRB 050813: I-band observations
  3. GRB050813, SDSS pre-burst observations
  4. GRB 050813: KAIT optical limit
  5. GRB 050813: Swift-BAT refined analysis
  6. GRB 050813: Photometry of object in XRT error circle
  7. GRB 050813: Swift XRT afterglow localization
  8. RBO GRB 050714A and GRB 050716 observations
  9. GRB 050813: Possible Short Swift-BAT GRB
  10. Swift-BAT trigger 150131 is not a GRB
  11. GRB050807(=H3889): An X-Ray Rich GRB Localized by HETE
  12. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  13. GRB050803: CrAO optical observations, no OT candidate
  14. GRB 050730: WSRT Radio Observations
  15. GRB 050803: PROMPT BVRcIc Observations
  16. GRB 050807: ROTSE-III Optical Limits
  17. GRB 050730, optical observation
  18. GRB050805b: CrAO optical limit
  19. GRB050805a : Null detection report
  20. GRB050730, optical observations
  21. GRB050803, optical observations
  22. Swift-BAT trigger 149118 is very likely not a GRB
  23. Retraction of Swift Trigger 149131 (GRB 050805B)
  24. GRB 050805b: OHP optical limits
  25. GRB 050805b: TAROT optical limits
  26. GRB050805b: MASTER optical observations
  27. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  28. GRB050805a: MASTER optical candidat
  29. Swift-BAT trigger 149118 is probably not a GRB
  30. GRB 050803: RTT150 optical observations
  31. GRB050803: CrAO optical observations, possible OT candidate
  32. GRB 050803: Keck Observations
  33. GRB 050803: Swift-BAT refined analysis
  34. GRB 050802.422: Fading of the afterglow and detection of the host
  35. GRB050803: MASTER further analys
  36. GRB 050803, optical observations
  37. GRB 050803: Magellan Observations
  38. GRB 050803: early Swift XRT analysis results
  39. GRB 050803: TAROT optical limits
  40. GRB050803: MASTER optical observations
  41. GRB050802: Tentative absorption redshift
  42. GCN GRB observation 050713A
  43. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  44. GRB 050802: Swift/UVOT optical and UV detections
  45. GRB050802: CrAO optical observations
  46. GRB050801: Unchanged decay slope
  47. GRB 050730: OHP optical observations
  48. GRB 050802: early Swift XRT analysis results
  49. GRB 050802: Swift/UVOT observations
  50. GRB 050802 : Lulin Optical follow-up observation
  51. GRB 050802: Swift-BAT refined analysis
  52. GRB050801: Optical photometry and decay index
  53. GRB 050802: XRT position
  54. GRB 050802: Swift Gamma-ray Burst
  55. GRB 050730: Preliminary Analysis of MIKE Spectrum
  56. GCN 050801: early Swift XRT analysis results
  57. GRB 050801: Swift-BAT refined analysis
  58. GRB 050801, SMARTS optical/IR afterglow observations
  59. GRB 050801, afterglow observations
  60. GRB 050730, corrected photometry and break?
  61. GRB 050801: ROTSE-III Early Afterglow Break
  62. GRB050801: Swift-BAT detection of a burst
  63. GRB 050801: ROTSE-III Detection of Possible Counterpart
  64. GRB 050730: XRT refined analysis
  65. Correction to GCN Circ 3476 on GRB050525A
  66. GRB 050730: early TAROT optical observations
  67. GRB 050726: PROMPT Rc Observations
  68. GRB 050730: RTT150 optical observations
  69. GRB 050730, spectra and optical photometry
  70. GRB050730: Refined BAT analysis of the Swift-BAT burst
  71. GRB 050730: Swift XRT afterglow observations
  72. GRB 050730 XMM-Newton observation
  73. GRB 050730: PROMPT VRcIc Observations
  74. GRB050730, afterglow observations
  75. GRB050730: confirmation of redshift
  76. GRB 050730: Redshift Measurement based on Magellan/MIKE Observations
  77. GRB 050730, SMARTS optical/IR afterglow observations
  78. GRB 050730 : Planned XMM-Newton observation
  79. GRB050730: Liverpool Telescope optical observations
  80. GRB 050730, optical candidate
  81. GRB050730: Swift-BAT detection of a weak burst
  82. GRB 050713A: Swift XRT extended light curve
  83. GRB 050709: PROMPT Rc Observations
  84. GRB050713b: Maidanak optical observations
  85. GRB 050724: Secure Host Redshift from Keck
  86. GRB 050724: WHT optical observations
  87. GRB 050724: Chandra Observations of the X-ray Afterglow
  88. GRB050713: analysis of the XMM-Newton observation
  89. GRB 050724, SMARTS optical/IR afterglow observations
  90. GRB 050726, SMARTS optical/IR observations
  91. Swift-BAT trigger 147918 is not a real GRB
  92. GRB 050727: RTT150 optical observations
  93. GRB050727: KAIT optical limit
  94. GRB050709: Second Epoch Chandra Observation
  95. GRB 050726: PROMPT Rc Observations
  96. GRB050709: Second Epoch Chandra Observation
  97. GRB 050724: dust-scattered X-ray halo detected in SWIFT/XRT observation
  98. GRB 050726: early Swift XRT analysis results
  99. GRB 050724: Optical Variability in Nearby Galaxy
  100. GRB 050724: J-band observations

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