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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. GRB 110411A : Xinglong TNT OT candidate
  2. GRB 110412A: Swift detection of a burst
  3. GRB 110411A, Swift-BAT refined analysis
  4. GRB 110411A: Enhanced Swift-XRT position
  5. GRB 110411A: MASTER optical observations
  6. GRB 110411A: Swift detection of a burst
  7. GRB 110328A / Swift J164449.3+573451: R-band Monitoring
  8. GRB 110407A: Swift-XRT refined Analysis
  9. GRB 110328A / Swift J164449.3+573451: MASTER pre, prompt and follow-up observations
  10. GRB 110407A:VLF observations on 20.27kHz
  11. GRB 110328A / Swift J164449.3+573451: optical observations
  12. GRB 110407A: SMARTS optical limit
  13. GRB 110328A / Swift J164449.3+573451: VLBA Observations
  14. GRB 110328A/Swift J164449.3+573451 UVOT Upper Limits
  15. GRB 110406A: Positional coincidence with NGC 404
  16. GRB 110407A: MASTER optical observations
  17. GRB110407A: UVOT Upper Limits
  18. GRB 110407A: GROND Detection of the Optical Afterglow
  19. GRB 110407A: MITSuME Okayama and Ishigakijima Optical upper limits
  20. GRB 110407A: NOT optical observations
  21. GRB 110407A: Enhanced Swift-XRT position
  22. GRB 110407A: Swift-BAT refined analysis
  23. GRB 100407A : Errata of afterglow position in GCN 11899
  24. IPN triangulation of the bright GRB110406A
  25. GRB 110407A : Lulin optical afterglow detection
  26. GRB 110407A : Xinglong TNT upper limit
  27. GRB 110407A: MASTER early optical observations
  28. GRB 110407A: Prompt enhanced Swift-XRT position
  29. GRB 110407A: Swift detection of a burst
  30. Konus-Wind observation of GRB 110406A
  31. Redshift of GRB 110402A theoretically estimated (revised)
  32. GRB 110328A/Swift J164449.3+573451: BAT recent rate increase and pre-outburst,light curve
  33. GRB 110406A: An exceptionally bright burst detected by INTEGRAL SPI-ACS
  34. GRB 110402A: fading optical afterglow
  35. Redshift of GRB 110402A theoretically estimated
  36. GRB 110402A: Suzaku WAM observation of the prompt emission
  37. GRB 110328/Swift J164449.3+573451: Chandra observations
  38. GRB 110402A: LOAO Optical Observation
  39. ICSP VLF observation of multiple SGR-like bursts from 1E 1841-045 on Feb. 9, 2011
  40. Comparison of ICSP VLF observation of GRB 090424 with satellite observations
  41. GRB 110328A / Swift J164449.3+573451: Keck LRIS R-band photometry
  42. GRB 110328A / Swift J164449.3+573451, HST Observations
  43. GRB 110328A / Swift J164449.3+573451: millimeter detection at PdBI
  44. GRB 110402A: Konus-Wind spectral lags and detailed energetics
  45. GRB 110401A: Fermi GBM detection
  46. GRB 110402A: Fermi GBM detection
  47. GRB 110402A: optical observations in Mondy
  48. GRB 110402A afterglow observation
  49. GRB 110328A / Swift J164449.3+573451: Keck/DEIMOS Optical Spectroscopy
  50. GRB 110402A: MITSuME Okayama and Ishigakijima Optical upper limits
  51. GRB 110328A/Swift J164449.3+573451: SARA-N detection
  52. GRB 110402A: Swift/UVOT detection of afterglow candidate
  53. GRB 110402A: Spectral lag indicates short hard burst
  54. Konus-Wind observation of GRB 110402A
  55. GRB 110402A: Konkoly observations
  56. GRB 110328A: Konkoly observations.
  57. GRB 110402A: Swift-BAT refined analysis
  58. GRB 110402A: Swift-XRT refined Analysis
  59. GRB 110402A: early optical limit by "Pi of the Sky"
  60. GRB 110402A: further NOT observations
  61. GRB110328A/Swift J164449.3+573451: Fermi LAT Observations
  62. GRB 110402A: PAIRITEL NIR Upper Limits
  63. GRB 110402A: Enhanced Swift-XRT position
  64. GRB 110402A: NOT afterglow confirmation
  65. GRB 110402A: Liverpool Telescope Observations
  66. GRB 110402A: Swift detection of a burst
  67. GRB 110328A / Swift J164449.3+573451: KASINICS NIR Observation
  68. GRB 110328A / Swift J164449.3+57345: Correction to GCN 11850
  69. GRB 110328A / Swift J164449.3+573451: Radio-optical/NIR Astrometry
  70. GRB 110328A / Swift J164449.3+573451: Infrared transient
  71. GRB 110328A / Swift J164449.3+573451: Mondy optical observations
  72. GRB 110328/Swift J164449.3+573451: Fermi observations
  73. GRB 110328A / Swift J164449.3+573451: KASINICS K-band Observation
  74. GRB 110328A / Swift J164449.3+573451
  75. GRB 110328A / Swift J164449.3+573451: EVLA observations of a brightening radio source
  76. GRB 110328A / Swift J164449.3+573451: X-ray analysis and a mini-blazar analogy
  77. GRB 110328A / Swift J164449.3+573451: Gemini and UKIRT IR observations
  78. GRB 110328A / Swift J164449.3+573451: PAIRITEL NIR Detection in 2nd Epoch
  79. GRB 110328A / Swift J164449.3+573451: No optical variability of the optical counterpart
  80. GRB 110328A / Swift J164449.3+573451: beamed emission
  81. GRB 110328A / Swift J164449.3+573451: BAT refined analysis
  82. GRB 110328A / Swift J164449.3+573451: CARMA mm detection
  83. GRB 110328A / Swift J164449.3+573451: Konkoly observations
  84. GRB 110328A / Swift J164449.3+573451: LOAO R-band Observation
  85. GRB 110328A / Swift J164449.3+573451: PAIRITEL NIR Upper Limits
  86. GRB 110328A / Swift J164449.3+573451: optical observations
  87. GRB 110328A / Swift J164449.3+573451: EVLA Detection
  88. GRB 110328B: Fermi-LAT Detection
  89. GRB 110328A / Swift J164449.3+573451: optical spectroscopy from GTC
  90. GRB 110328A: Gemini spectroscopic observations
  91. GRB 110213A, the review of the sky area in plate archives
  92. GRB 110328B: Fermi GBM detection
  93. GRB 110328A / Swift J164449.3+573451: NOT optical observations.
  94. GRB 110328A/ Swift J164449.3+573451 : Xinglong TNT Upper limit
  95. GRB / X-ray transient 110328A: MITSuME OkayamaOptical upper limits
  96. GRB 110328A / Swift J164449.3+573451: PTF Quiescent Optical Counterpart
  97. GRB 110328A: Enhanced Swift-XRT position
  98. GRB / X-ray transient 110328A: Gemini optical observations
  99. GRB 110328A: a second trigger, probably a hard X-ray transient (Swift J164449.3+573451)
  100. GRB 110328A: Swift detection of a burst

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