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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"
  1. GRB110407A: UVOT Upper Limits
  2. GRB 110407A: GROND Detection of the Optical Afterglow
  3. GRB 110407A: MITSuME Okayama and Ishigakijima Optical upper limits
  4. GRB 110407A: NOT optical observations
  5. GRB 110407A: Enhanced Swift-XRT position
  6. GRB 110407A: Swift-BAT refined analysis
  7. GRB 100407A : Errata of afterglow position in GCN 11899
  8. IPN triangulation of the bright GRB110406A
  9. GRB 110407A : Lulin optical afterglow detection
  10. GRB 110407A : Xinglong TNT upper limit
  11. GRB 110407A: MASTER early optical observations
  12. GRB 110407A: Prompt enhanced Swift-XRT position
  13. GRB 110407A: Swift detection of a burst
  14. Konus-Wind observation of GRB 110406A
  15. Redshift of GRB 110402A theoretically estimated (revised)
  16. GRB 110328A/Swift J164449.3+573451: BAT recent rate increase and pre-outburst,light curve
  17. GRB 110406A: An exceptionally bright burst detected by INTEGRAL SPI-ACS
  18. GRB 110402A: fading optical afterglow
  19. Redshift of GRB 110402A theoretically estimated
  20. GRB 110402A: Suzaku WAM observation of the prompt emission
  21. GRB 110328/Swift J164449.3+573451: Chandra observations
  22. GRB 110402A: LOAO Optical Observation
  23. ICSP VLF observation of multiple SGR-like bursts from 1E 1841-045 on Feb. 9, 2011
  24. Comparison of ICSP VLF observation of GRB 090424 with satellite observations
  25. GRB 110328A / Swift J164449.3+573451: Keck LRIS R-band photometry
  26. GRB 110328A / Swift J164449.3+573451, HST Observations
  27. GRB 110328A / Swift J164449.3+573451: millimeter detection at PdBI
  28. GRB 110402A: Konus-Wind spectral lags and detailed energetics
  29. GRB 110401A: Fermi GBM detection
  30. GRB 110402A: Fermi GBM detection
  31. GRB 110402A: optical observations in Mondy
  32. GRB 110402A afterglow observation
  33. GRB 110328A / Swift J164449.3+573451: Keck/DEIMOS Optical Spectroscopy
  34. GRB 110402A: MITSuME Okayama and Ishigakijima Optical upper limits
  35. GRB 110328A/Swift J164449.3+573451: SARA-N detection
  36. GRB 110402A: Swift/UVOT detection of afterglow candidate
  37. GRB 110402A: Spectral lag indicates short hard burst
  38. Konus-Wind observation of GRB 110402A
  39. GRB 110402A: Konkoly observations
  40. GRB 110328A: Konkoly observations.
  41. GRB 110402A: Swift-BAT refined analysis
  42. GRB 110402A: Swift-XRT refined Analysis
  43. GRB 110402A: early optical limit by "Pi of the Sky"
  44. GRB 110402A: further NOT observations
  45. GRB110328A/Swift J164449.3+573451: Fermi LAT Observations
  46. GRB 110402A: PAIRITEL NIR Upper Limits
  47. GRB 110402A: Enhanced Swift-XRT position
  48. GRB 110402A: NOT afterglow confirmation
  49. GRB 110402A: Liverpool Telescope Observations
  50. GRB 110402A: Swift detection of a burst
  51. GRB 110328A / Swift J164449.3+573451: KASINICS NIR Observation
  52. GRB 110328A / Swift J164449.3+57345: Correction to GCN 11850
  53. GRB 110328A / Swift J164449.3+573451: Radio-optical/NIR Astrometry
  54. GRB 110328A / Swift J164449.3+573451: Infrared transient
  55. GRB 110328A / Swift J164449.3+573451: Mondy optical observations
  56. GRB 110328/Swift J164449.3+573451: Fermi observations
  57. GRB 110328A / Swift J164449.3+573451: KASINICS K-band Observation
  58. GRB 110328A / Swift J164449.3+573451
  59. GRB 110328A / Swift J164449.3+573451: EVLA observations of a brightening radio source
  60. GRB 110328A / Swift J164449.3+573451: X-ray analysis and a mini-blazar analogy
  61. GRB 110328A / Swift J164449.3+573451: Gemini and UKIRT IR observations
  62. GRB 110328A / Swift J164449.3+573451: PAIRITEL NIR Detection in 2nd Epoch
  63. GRB 110328A / Swift J164449.3+573451: No optical variability of the optical counterpart
  64. GRB 110328A / Swift J164449.3+573451: beamed emission
  65. GRB 110328A / Swift J164449.3+573451: BAT refined analysis
  66. GRB 110328A / Swift J164449.3+573451: CARMA mm detection
  67. GRB 110328A / Swift J164449.3+573451: Konkoly observations
  68. GRB 110328A / Swift J164449.3+573451: LOAO R-band Observation
  69. GRB 110328A / Swift J164449.3+573451: PAIRITEL NIR Upper Limits
  70. GRB 110328A / Swift J164449.3+573451: optical observations
  71. GRB 110328A / Swift J164449.3+573451: EVLA Detection
  72. GRB 110328B: Fermi-LAT Detection
  73. GRB 110328A / Swift J164449.3+573451: optical spectroscopy from GTC
  74. GRB 110328A: Gemini spectroscopic observations
  75. GRB 110213A, the review of the sky area in plate archives
  76. GRB 110328B: Fermi GBM detection
  77. GRB 110328A / Swift J164449.3+573451: NOT optical observations.
  78. GRB 110328A/ Swift J164449.3+573451 : Xinglong TNT Upper limit
  79. GRB / X-ray transient 110328A: MITSuME OkayamaOptical upper limits
  80. GRB 110328A / Swift J164449.3+573451: PTF Quiescent Optical Counterpart
  81. GRB 110328A: Enhanced Swift-XRT position
  82. GRB / X-ray transient 110328A: Gemini optical observations
  83. GRB 110328A: a second trigger, probably a hard X-ray transient (Swift J164449.3+573451)
  84. GRB 110328A: Swift detection of a burst
  85. GRB110318B : MOA optical upper limit
  86. Fermi Gamma-ray Burst Monitor trigger 322686470 (110324797) is not a GRB
  87. GRB 110319B Swift-XRT afterglow confirmation
  88. GRB 101225A: revised analysis of narrow band imaging
  89. GRB 110319B BAT refined analysis
  90. GRB 110319B: Swift/UVOT Upper Limits
  91. GRB 110318B: Swift/UVOT Upper Limits
  92. GRB 110319B: GROND upper limits
  93. GRB 110319B: Swift-XRT afterglow candidate.
  94. GRB 110319B found in ground analysis of Swift-BAT data
  95. GRB 110319A: Swift/UVOT Detection
  96. GRB 110319A: Swift-BAT refined analysis
  97. GRB 110319A: Swift-XRT refined Analysis
  98. GRB 110318B: GROND upper limits
  99. GRB 110319A: Enhanced Swift-XRT position
  100. GRB 110319A: Swift detection of a burst

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