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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"

19534 results found.

  1. GRB 090715B: MASTER optical limit
  2. GRB 090715A: Swift-BAT refined analysis
  3. GRB 090715B: Swift/UVOT followup observations
  4. GRB 090715B: break in the optical afterglow decay
  5. GRB 090715B: Enhanced Swift-XRT position
  6. GRB 090715B: Swift XRT Refined Analysis
  7. GRB 090715B: Swift-BAT refined analysis
  8. GRB 090715B - Liverpool Telescope Optical Afterglow Candidate
  9. Swift problem fixed
  10. GRB 090715B: Swift detection of a burst with a possible optical counterpart
  11. GRB 090715A: ROTSE-III Optical Limits
  12. GRB 090715: Swift detection of a short hard burst
  13. Swift satellite anomaly
  14. GRB 090712: Fermi GBM observation
  15. GRB 090712: Swift-BAT refined analysis
  16. GRB 090712: Swift detection of a burst
  17. GRB 090621B: MTM-500 optical observations
  18. GRB 090709A: deep optical observation with the 10.4m GTC
  19. GRB 090709A: Suzaku WAM observation of the prompt emission
  20. GRB 090709A: Swift UVOT upper limits
  21. GRB 090709B: Fermi GBM detection
  22. GRB 090709A: confirmation of the periodicity in the SPI-ACS data
  23. GRB 090709A: evidence for a very red afterglow at low z
  24. GRB 090709A: RAPTOR Limits During Gamma-Ray Emission
  25. GRB 090709A: Swift XRT Refined Analysis
  26. GRB 090709B, Swift-BAT refined analysis
  27. GRB 090709A: Swift-BAT refined analysis
  28. GRB090709A: High Energy BAT/XRT Analysis Suggests Low to Moderate Redshift
  29. GRB 090709A: Wyoming Infrared Observatory NIR upper limits
  30. GRB 090709A, RIMOTS optical upper limits
  31. GRB 090709A: Enhanced Swift-XRT position
  32. GRB 090709B: Swift detection of a burst
  33. GRB 090708 : Fermi GBM detection
  34. GRB 090709: Faulkes Telescope North Upper Limits
  35. GRB 090709: PAIRITEL NIR Upper Limits
  36. GRB 090709: ROTSE-III Optical Limits
  37. GRB 090709: Swift detection of a bright burst
  38. GRB 090708: Early RAPTOR Optical Limits
  39. GRB 090708, Swift-BAT refined analysis
  40. GRB 090708: ROTSE-III Optical Limits
  41. GRB 090708: Swift detection of a burst
  42. Swift-BAT trigger 356516 is not a GRB
  43. Possible GRB090705: Swift-XRT observations
  44. GRB 090705: PAIRITEL NIR Observations
  45. GRB 090705: Swift detection of a possible burst
  46. XRF 090702 : RTT150 optical observations
  47. GRB 090618: Mondy optical observations
  48. GRB 090529: CrAO optical upper limit
  49. GRB 090529: MTM-500 optical observations
  50. GRB 090529: Mt.Terskol optical observations
  51. XRF 090702: Swift-XRT refined analysis
  52. GRB 090702: UVOT upper limits
  53. XRF 090702: Swift-XRT afterglow position
  54. GRB 090628: Swift XRT refined analysis
  55. GRB 090618: RTT150 optical observations
  56. GRB 090628: Swift/UVOT Upper Limits
  57. GRB 090628: Swift-BAT refined analysis
  58. GRB 090628: GROND upper limits
  59. GRB 090628: Enhanced Swift-XRT position
  60. GRB 090626: IPN localization
  61. GRB 090628: Swift/UVOT Finding Chart Observation
  62. GRB 090628: Swift XRT position
  63. GRB 090628: Swift detection of a burst
  64. GRB 090625B: Swift/UVOT Upper Limits
  65. GRB 090625B: Swift-XRT refined analysis
  66. GRB 090625B: Swift observation of the INTEGRAL GRB 090625B
  67. GRB 090621A: Enhanced Swift-XRT position
  68. GRB 090621B: GRT Optical Observation
  69. GRB 090621A: GRT Optical Observation
  70. PAIRITEL observations of GRB 090618
  71. GRB 090621B: Fermi GBM detection
  72. GRB 090621B: I-band observations from 1.23m CAHA
  73. GRB 090621: Fermi GBM observation
  74. GRB 090621B: Swift/UVOT Upper Limits
  75. GRB 090621B: Swift-BAT refined analysis
  76. GRB 090621B: Swift-XRT refined analysis
  77. GRB 090621B: RTT150 optical observations
  78. GRB 090618: RTT150 optical observations
  79. GRB 090621A: Swift-BAT refined analysis
  80. GRB 090621B: Swift detection of a short hard burst
  81. GRB 090621: Swift/UVOT Upper Limits
  82. GRB 090621: Swift-XRT Team refined analysis
  83. GRB 090621: Swift detection of a burst
  84. GRB 090618: ZTSh optical observations
  85. GRB090618, underlying supernova search
  86. GRB 090618: Fermi GBM observation
  87. GRB 090618, Swift-BAT refined spectral analysis
  88. GRB090618 - Continued optical monitoring and light curve break
  89. GRB 090618: Swift-BAT refined analysis
  90. GRB090618: Swift-XRT team refined analysis
  91. GRB090618: Swift/UVOT bright afterglow detection
  92. Swift XRT observations of GRB 090531A
  93. GRB 090618: AGILE observations
  94. GRB 090618: Enhanced Swift-XRT position
  95. GRB 090618 Faulkes Telescope North observations
  96. GRB 090618: ROTSE-III Detection of Optical Counterpart
  97. GRB090618: P60 Optical Afterglow
  98. GRB 090618: Swift detection of a bright burst with optical afterglow
  99. SGR 0418+5729 Fermi/GBM Detection of Pulsations
  100. RXTE Discovery of Pulsations from SGR 0418+5729

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