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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 110503A: Centimeter observation from EVLA
  2. GRB 110503A: Millimeter observation from SMA
  3. GRB 110503A: SARA-N Observations and Photometric Calibration
  4. GRB 110503A: Swift/UVOT Observations
  5. GRB 110503A: Swift-XRT refined Analysis
  6. GRB 110503A: PAIRITEL NIR Detection
  7. GRB 110503A: redshift confirmation from TNG
  8. GRB 110503A - TLS Afterglow Observations
  9. GRB 110503A: Swift-BAT refined analysis
  10. GRB 110503A: NOT afterglow photometry
  11. GRB 110503A: Redshift from 10.4m GTC
  12. GRB 110503A: Enhanced Swift-XRT position
  13. GRB 110503A: Swift detection of a burst with a bright optical counterpart
  14. GRB 110426A: Swift/XRT non-detection
  15. GRB 110428A : X-ray afterglow confirmation
  16. GRB 110428A: Suzaku WAM observation of the prompt emission
  17. Fermi-GBM data processing and delivery
  18. GRB 110422A: optical observations in CrAO
  19. GRB 110422A: Update of Herschel FIR observation schedule
  20. GRB 110428A : Swift-XRT observations
  21. Konus-Wind observation of GRB 110428A
  22. GRB 110428A: Fermi-LAT Detection
  23. GRB 110426A: MASTER synchronous with MAXI/GSC observations
  24. GRB 110426A: MAXI/GSC detection of a GRB
  25. GRB 110422A: optical observations in CrAO, second epoch
  26. GRB 110422A: Redshift confirmation from GTC
  27. GRB 110422A: tentative redshift from TNG
  28. GRB 110422A: Suzaku WAM observation of the prompt emission
  29. GRB 110422A: Herschel observation scheduled
  30. GRB110422A: NOT optical follow-ups
  31. GRB 110422A: optical observations in CrAO
  32. GRB110422A: MITSuME Ishigakijima Optical Observation
  33. Konus-Wind observation of GRB 110422A
  34. GRB 110422A: Further NOT observation
  35. GRB 110422A: Swift/UVOT Detection of optical afterglow
  36. GRB 110422A: Swift-XRT refined Analysis
  37. GRB 110422A: CQUEAN griz Observation
  38. GRB 110422A: THO optical observations
  39. GRB 110422A: Enhanced Swift-XRT position
  40. GRB 110422A: correction to the GCN circ. 11958
  41. GRB 110422A: TNG optical observations
  42. GRB 110422A: SAO RAS optical observations
  43. GRB 110422A: NOT optical observation
  44. GRB 110422A: MASTER earlier OT polarization observations
  45. GRB 110422A: Swift-BAT refined analysis
  46. GRB 110422A: Mondy optical observations
  47. GRB 110422A: Swift detection of a burst
  48. GRB 110328A/Swift J164449.3+573451: Maidanak Optical Observation
  49. GRB 110420B: Swift/UVOT Upper Limits
  50. GRB110420A: GROND detection of the Optical/NIR Afterglow Candidate
  51. GRB 110420B: Swift-XRT afterglow candidate retraction
  52. GRB 110420B: Fermi GBM observation
  53. Konus-Wind observation of GRB 110420A
  54. GRB 110420B: Spectral lag indicates short hard burst
  55. GRB 110420B, GROND observations
  56. GRB 110420A Swift/UVOT Observations
  57. GRB 110420B: Swift-XRT afterglow candidate
  58. GRB 110420B: Swift-BAT refined analysis
  59. GRB 110420A: Swift-BAT refined analysis
  60. GRB 110420B: Swift detection of a short hard burst
  61. GRB 110420A: Swift-XRT refined Analysis
  62. GRB 110420A: Enhanced Swift-XRT position
  63. GRB 110420A: Swift detection of a burst with optical counterpart
  64. GRB110414A: MITSuME Ishigakijima Optical upper limits
  65. GRB 110414A: GROND upper limits
  66. GRB110414A: MITSuME Okayama Optical upper limits
  67. GRB 110414A: Swift-BAT Refined Analysis
  68. GRB 110414A: Swift/UVOT Upper limits
  69. GRB 110414A: Swift-XRT refined Analysis
  70. GRB 110414A: Enhanced Swift-XRT position
  71. GRB 110328A / Swift J164449.3+573451: WISE quiescent source upper limit
  72. GRB 110414A : Faulkes Telescope North observations
  73. GRB 110414A: Swift detection of a burst
  74. GRB 110411A: PAIRITEL NIR Upper Limits
  75. GRB 110412A: Swift-BAT refined analysis
  76. GRB 110411A: optical limits from OSN
  77. GRB 110411A: Swift-XRT refined Analysis
  78. GRB 110412A: Fermi GBM observation
  79. GRB 110411A: Swift/UVOT Upper Limits
  80. GRB 110411A: MASTER prompt and follow-up optical limits
  81. GRB 110411A : Xinglong TNT OT candidate
  82. GRB 110412A: Swift detection of a burst
  83. GRB 110411A, Swift-BAT refined analysis
  84. GRB 110411A: Enhanced Swift-XRT position
  85. GRB 110411A: MASTER optical observations
  86. GRB 110411A: Swift detection of a burst
  87. GRB 110328A / Swift J164449.3+573451: R-band Monitoring
  88. GRB 110407A: Swift-XRT refined Analysis
  89. GRB 110328A / Swift J164449.3+573451: MASTER pre, prompt and follow-up observations
  90. GRB 110407A:VLF observations on 20.27kHz
  91. GRB 110328A / Swift J164449.3+573451: optical observations
  92. GRB 110407A: SMARTS optical limit
  93. GRB 110328A / Swift J164449.3+573451: VLBA Observations
  94. GRB 110328A/Swift J164449.3+573451 UVOT Upper Limits
  95. GRB 110406A: Positional coincidence with NGC 404
  96. GRB 110407A: MASTER optical observations
  97. GRB110407A: UVOT Upper Limits
  98. GRB 110407A: GROND Detection of the Optical Afterglow
  99. GRB 110407A: MITSuME Okayama and Ishigakijima Optical upper limits
  100. GRB 110407A: NOT optical observations

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