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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"

37512 results found.

  1. GRB 141121A: Mondy optical observations
  2. GRB 141121A: LCO-FTN rebrightening confirmation
  3. GRB 141121A: MITSuME Ishigakijima Optical Observation
  4. GRB 141121A: Continued RATIR Optical Observations - Rebrightening
  5. GRB 141121A: AAO optical observations
  6. GRB 141121A: MITSuME Akeno Optical observation
  7. GRB 141121A: Continued RATIR Optical Observations
  8. GRB 141121A: Swift-XRT refined Analysis
  9. GRB 141121A: Swift/UVOT Detections
  10. GRB 141121A: RATIR Optical Observations
  11. GRB 141121A: Swift-BAT refined analysis
  12. GRB 141121A: LCO-FTN observations
  13. GRB 141121A: Keck redshift
  14. GRB 141121A: Enhanced Swift-XRT position
  15. GRB 141118A: iPTF Optical Observations
  16. GRB 141121A: GROND Afterglow candidate
  17. GRB 141121A: MAXI/GSC detection
  18. GRB141121A: BOOTES-2/TELMA upper limit
  19. GRB 141121A: Swift detection of a burst
  20. Konus-Wind observation of GRB 141118A
  21. IPN Triangulation of GRB 141118A
  22. GRB 141109A: further VLA observations
  23. GRB 141104A: further Swift-XRT observations and afterglow candidate
  24. GRB 141109A: VLA detection
  25. GRB 141109B: optical upper limits
  26. GRB 141015A: TAROT La Silla observatory optical observations
  27. GRB 141022A: TAROT La Silla observatory optical observations
  28. GRB 141031A: TAROT La Silla observatory optical observations
  29. GRB 141109A: TAROT La Silla observatory optical observations
  30. GRB 141109A: AAO optical observations
  31. GRB 141109A: Terskol photometry
  32. GRB 141109B: Swift/UVOT Upper Limits
  33. GRB 141109A: Swift/UVOT Detection
  34. GRB 141109A: NOT r-band observation
  35. Konus-Wind observation of GRB 141109A
  36. GRB 141109B: MITSuME Akeno upper limits
  37. GRB141109A : Xinglong TNT optical observation
  38. GRB 141109B: IRAM 30m millimetre observations
  39. GRB 141109B: Swift-XRT refined Analysis
  40. GRB 141109A: MITSuME Ishigakijima upper limits
  41. GRB 141109A: Swift-XRT refined Analysis
  42. GRB 141109B: BOOTES-4 and TERSKOL optical upper limit
  43. GRB 141109B: Swift-BAT refined analysis
  44. GRB 141109B: Enhanced Swift-XRT position
  45. GRB 141109A: Swift-BAT refined analysis
  46. GRB 141109A: Enhanced Swift-XRT position
  47. GRB 141109A: CQUEAN Detection at 0.85 - 1.05 micron
  48. GRB 141109A: GROND afterglow observation
  49. X-shooter redshift of GRB 141109A
  50. GRB 141109A: REM NIR candidate afterglow
  51. GRB 141109B: Swift detection of a burst
  52. GRB 141109A: Swift detection of a burst
  53. GRB 141104A: Swift-XRT observations
  54. GRB 141028A: Mondy optical observations
  55. GRB 141104A Tiled Swift observations
  56. GRB 141026A: CrAO optical observation
  57. GRB
  58. GRB 141026A: Gemini-North optical and NIR imaging
  59. GRB 141028A: TShAO optical observation
  60. GRB 141031B: TShAO optical observations
  61. GRB 141017A: Skynet PROMPT-CTIO/SSO Observations
  62. Konus-Wind observation of GRB 141104A
  63. IPN Triangulation of GRB 141104A (long/very bright)
  64. GRB 141102A possible precursor was another, known source
  65. Konus-Wind observation of GRB 141102A
  66. GRB 141022A: Skynet PROMPT-CTIO Observations
  67. GRB 141102A: Fermi-LAT detection
  68. GRB 141102A: Fermi GBM detection
  69. GRB 141102A found in ground analysis of BAT data
  70. GRB 141026A: VLA observations
  71. GRB 141031B: RATIR Optical and NIR Observation
  72. GRB 141031B: Swift/UVOT Upper Limits
  73. MAXI GRB 141029A is likely an X-ray flare from 1RXS J043657.1-161258
  74. GRB 141031B: Swift-XRT refined Analysis
  75. GRB 141031B: Bassano Bresciano Observatory upper limit
  76. GRB 141031B: NOT optical observations
  77. GRB 141031B: MITSuME Ishigakijima upper limits
  78. GRB 141031B: Swift-BAT refined analysis
  79. GRB 141031A, Swift-BAT refined analysis
  80. GRB 141031B: Enhanced Swift-XRT position
  81. GRB 141031A: Swift/UVOT Upper Limits
  82. GRB 141031B: TShAO optical upper limit
  83. GRB 141031B: 1.23m CAHA I-band observations
  84. GRB 141031A: Swift-XRT refined Analysis
  85. GRB 141031A: Skynet PROMPT-CTIO Observations
  86. GRB 141004A: Continued Late Time RATIR Optical and NIR Observations
  87. GRB 141031A: VLT/X-shooter optical observations
  88. GRB 141031A: Fermi GBM detection
  89. GRB 141031B: Nanshan optical upper limit
  90. GRB 141031B: MASTER early optical observations
  91. GRB 141031B: Swift detection of a burst
  92. GRB 141031A: Enhanced Swift-XRT position
  93. GRB 141031A: GROND detection of a possible optical afterglow candidate
  94. GRB 141031A: Swift detection of a burst
  95. GRB 141029A: Nanshan optical upper limit
  96. GRB 141028A: SAO RAS Zeiss-1000 photometry
  97. GRB 140509A: GROND afterglow detection
  98. GRB 141028A: Continued RATIR Observations
  99. GRB 141028A: Swift/UVOT followup observations
  100. GRB 141028A: P60 Observations and Decay Index

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