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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"

42205 results found.

  1. GRB050326: optical limit 33min before GRB
  2. GRB 050326 BAT refined analysis
  3. GRB050326: delayed XRT observation
  4. Swift-BAT detection of a bright GRB 050326
  5. GRB050319, optical observations
  6. GRB050319, color indices
  7. GRB050319: optical observation, March 20-22
  8. GRB050319: RTT150 Optical Observations
  9. Swift-BAT detection of a bright outburst from SGR1806-20
  10. GRB 050319: Absorption redshift from the Nordic Optical Telescope
  11. GRB 050319: ROTSE-III Refined Analysis
  12. GRB 050318: Swift-BAT refined analysis
  13. Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
  14. GRB050319: VLA Observations
  15. GRB050319: radio observation
  16. GRB 050319 R band observations
  17. GRB 050319: Swift-UVOT detection of the afterglow
  18. GRB 050315: Variability Analysis of Swift BAT Time History
  19. GRB050319: Radio Observations
  20. GRB 050319: NIR afterglow candidate
  21. GRB 050319:Near IR afterglow
  22. GRB050319: BR optical photometry
  23. GRB 050318: SWIFT-UVOT refined analysis
  24. GRB 050319: Optical observation
  25. GRB 050319 : Confirmation of optical afterglow decay
  26. GRB050319,optical observation
  27. Swift Detection of GRB 050319
  28. GRB 050319: Detection of Possible Optical Counterpart
  29. GRB 050318: Swift/UVOT detection of afterglow emission
  30. GRB 050318: Magellan optical afterglow identification
  31. GRB050318: Swift XRT position
  32. RXTE Observations of GRB050318
  33. Swift-BAT detection of GRB 050318
  34. GRB 050315, SMARTS optical afterglow decay
  35. GRB050223: analysis of the XMM-Newton observation
  36. GRB050316: MASTER before, simultanious and follow up optical
  37. GRB 050306: ROTSE-III early limits
  38. GRB050316: MASTER optical observations
  39. GRB 050315: Swift-BAT further refined analysis
  40. GRB 050315, SMARTS optical/IR afterglow observations
  41. GRB 050315 I-band observations
  42. GRB050315: Radio afterglow
  43. GRB 050315: Optical afterglow identification
  44. GRB 050315: Swift XRT Position
  45. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  46. GRB 050315: Early Observations with Swift/UVOT
  47. Swift-BAT detection of GRB 050315
  48. GRB050223: No XMM-Newton OM detection of afterglow emission
  49. GRB 050306: Radio Observations
  50. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  51. GRB050309: CONCAM pre-trigger and trigger coincident optical
  52. GRB 050306: optical afterglow
  53. GRB 050126: Redshift determination
  54. Swift-BAT trigger 107873: No Swift XRT counterpart
  55. GRB 050309, Early optical limits from RAPTOR
  56. GRB 050306: further TAROT optical data
  57. GRB050309: Early optical limit from P60
  58. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  59. GRB 050309 : Lulin R-band observation
  60. Swift 107873: P60 Optical Observations
  61. GRB 050306: CORRECTION to date of observation
  62. GRB 050306: R-band observations
  63. GRB 050306: No Swift UVOT Optical Counterpart Detected
  64. GRB 050306: REM optical-infrared observations
  65. GRB 050306: Possible X-ray Afterglow Position from the Swift
  66. Swift trigger 107518: optical observation
  67. GRB 050306: TAROT optical observations
  68. GRB 050306,optical observation
  69. GRB 050306: Swift-BAT detection of a long burst
  70. Ongoing activity of SGR 1806-20 after the giant flare
  71. GRB050215B: Late-Time Swift UVOT Observations
  72. GRB 050126: Confirmation of the NIR afterglow candidate
  73. PROMPT VRcIc Observations of GRB 050223
  74. XRF/GRB 050215B: Radio Observations
  75. GRB 050219b: candidate NIR afterglow
  76. Confirmed XRF nature for GRB050215b
  77. GRB 050223: optical observations
  78. GRB050223 XMM-Newton observation
  79. INTEGRAL detection of GRB 050223
  80. GRB 050223 : Planned XMM-Newton observation
  81. GRB050223: No Swift UVOT Detection of Afterglow Emission
  82. GRB050223: ROTSE-III Optical Observations
  83. GRB 050223 Swift/BAT detection of a burst
  84. GRB 050223: Swift XRT Position
  85. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  86. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  87. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  88. GRB 050219b: CORRECTION to refined XRT position
  89. GRB 050219a: Optical observations from LCO
  90. GRB 050219b: Optical and near-IR observations from LCO
  91. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  92. GRB 050219b: Swift-BAT detection of a burst
  93. GRB 050219b: CORRECTION: Swift XRT Position
  94. GRB 050219b: Swift XRT Position
  95. GRB 050219a, optical observations
  96. GRB 050219a: Refined XRT position
  97. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  98. GRB 050219: Swift-BAT detection of a burst
  99. GRB050215b: Swift UVOT Detection of Afterglow Emission
  100. GRB 050219: Prompt X-ray position

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