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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 090709B: Fermi GBM detection
  2. GRB 090709A: confirmation of the periodicity in the SPI-ACS data
  3. GRB 090709A: evidence for a very red afterglow at low z
  4. Konus-Wind and Konus-RF observations of GRB 090709A
  5. GRB 090709A: P60 Observations
  6. GRB 090709A: Quasiperiodic variations in the BAT light curve
  7. GRB 090709A: NOT optical observations
  8. GRB 090709A: RAPTOR Limits During Gamma-Ray Emission
  9. GRB 090709A: Swift XRT Refined Analysis
  10. GRB 090709B, Swift-BAT refined analysis
  11. GRB 090709A: Swift-BAT refined analysis
  12. GRB090709A: High Energy BAT/XRT Analysis Suggests Low to Moderate Redshift
  13. GRB 090709A: Wyoming Infrared Observatory NIR upper limits
  14. GRB 090709A, RIMOTS optical upper limits
  15. GRB 090709A: Enhanced Swift-XRT position
  16. GRB 090709A - PAIRITEL Discovery of a Red Afterglow
  17. GRB 090709A: Subaru NIR observation
  18. GRB 090709B: Swift detection of a burst
  19. GRB 090709 : planned Suzaku-ToO observation
  20. GRB 090708 : Fermi GBM detection
  21. GRB 090709: Faulkes Telescope North Upper Limits
  22. GRB 090626: Suzaku WAM observation of the prompt emission
  23. GRB 090709: PAIRITEL NIR Upper Limits
  24. GRB 090704: Fermi GBM observation
  25. GRB 090709: ROTSE-III Optical Limits
  26. GRB 090709: Swift detection of a bright burst
  27. GRB 090708: Early RAPTOR Optical Limits
  28. GRB 090708, Swift-BAT refined analysis
  29. GRB 090708: ROTSE-III Optical Limits
  30. GRB 090708: Swift detection of a burst
  31. GRB 090704: a long GRB found in INTEGRAL off-line analysis
  32. GRB 090706: Fermi GBM detection
  33. Swift-BAT trigger 356516 is not a GRB
  34. Possible GRB090705: Swift-XRT observations
  35. GRB 090705: PAIRITEL NIR Observations
  36. GRB 090705: Swift detection of a possible burst
  37. XRF 090702 : RTT150 optical observations
  38. GRB 090618: Mondy optical observations
  39. GRB 090529: CrAO optical upper limit
  40. GRB 090529: MTM-500 optical observations
  41. GRB 090529: Mt.Terskol optical observations
  42. XRF 090702: Swift-XRT refined analysis
  43. GRB 090703: Fermi GBM detection
  44. GRB 090702: UVOT upper limits
  45. GRB 090313: optical observations
  46. XRF 090702: VLT imaging
  47. XRF 090702: Swift-XRT afterglow position
  48. XRF 090702: a long soft GRB localized with INTEGRAL
  49. GRB 090404: Deep optical imaging and possible host association (correction)
  50. GRB 090404: Deep optical imaging and possible host association
  51. GRB 090701: Fermi GBM detection
  52. GRB 090628: Swift XRT refined analysis
  53. GRB 090630: Fermi GBM detection
  54. GRB 090618: RTT150 optical observations
  55. GRB 090628: Swift/UVOT Upper Limits
  56. Konus-Wind observation of GRB 090626
  57. GRB080628: SAO RAS optical observations
  58. GRB 090628: Swift-BAT refined analysis
  59. GRB090618: 15GHz radio emission faded
  60. GRB 090628: GROND upper limits
  61. GRB 090628: Enhanced Swift-XRT position
  62. GRB 090628: 1.23m CAHA optical observations
  63. GRB 090626: IPN localization
  64. GRB 090628: Swift/UVOT Finding Chart Observation
  65. GRB 090628: Swift XRT position
  66. GRB 090628: Swift detection of a burst
  67. Fermi LAT observations of GRB 090626
  68. GRB 090625B: Fermi GBM observation
  69. GRB 090423: Spitzer observations of the z~8.3 burst
  70. GRB 090625B: Swift/UVOT Upper Limits
  71. GRB 090625B: Swift-XRT refined analysis
  72. GRB 090626: Fermi GBM detection
  73. GRB 090625B: GROND upper limits
  74. GRB 090623: Suzaku WAM observation of the prompt emission
  75. GRB090618: HCT optical observations
  76. GRB 090618: SARA Second Epoch Observations
  77. GRB 090625B: Faulkes Telescope South observations
  78. GRB 090625B: Swift observation of the INTEGRAL GRB 090625B
  79. GRB 090625B: a long GRB localized by INTEGRAL
  80. GRB 090625: Fermi GBM detection
  81. GRB 090618: Correction to GCN 9568
  82. GRB 090617: Suzaku WAM observation of the prompt emission
  83. GRB 090618: Suzaku WAM observation of the prompt emission
  84. GRB 090621A: Enhanced Swift-XRT position
  85. GRB 090623: Fermi GBM detection
  86. GRB 090621B: GRT Optical Observation
  87. GRB 090621A: GRT Optical Observation
  88. PAIRITEL observations of GRB 090618
  89. GRB 090621B: Fermi GBM detection
  90. GRB 090621B: I-band observations from 1.23m CAHA
  91. GRB 090621D: Fermi GBM detection
  92. GRB 090621B: Gemini spectrum of afterglow candidate
  93. GRB 090621C: Fermi GBM detection
  94. GRB 090621B: P60 Observations
  95. GRB 090621: Fermi GBM observation
  96. GRB 090621B: VLA observations
  97. GRB 090620: Fermi GBM detecion
  98. Konus-Wind and Konus-RF observations of GRB 090618
  99. GRB 090621B: Swift/UVOT Upper Limits
  100. GRB 090621B: Swift-BAT refined analysis

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